Silver-Russell syndrome (SRS) [OMIM 180860] is a clinically and genetically heterogeneous congenital imprinting disorder. It was first described in 1953 by Dr Henry Silver and his colleagues, who reported two children with short stature and congenital hemihypertrophy.1 In the following year, Dr Alexander Russell reported five similar cases with intrauterine dwarfism and craniofacial dysostosis.2 The term SRS has been used since 1970 to describe a constellation of features with intrauterine growth retardation without postnatal catch-up, distinct facial characteristics, relative macrocephaly, body asymmetry, and/or fifth finger clinodactyly.3 4 The prevalence of SRS was estimated to be 1 in 100 000,5 but was probably underestimated due to the diverse and variable clinical manifestations. The majority of SRS cases are sporadic, although occasional familial cases have been reported.

Two major molecular mechanisms have been implicated in SRS—maternal uniparental disomy of chromosome 7 (mUPD7)6 and loss of DNA methylation (LOM) of the imprinting control region 1 (ICR1) on the paternal allele of chromosome 11p15 region that regulates the IGF2/H19 locus.6 7 8 9 According to the studies, LOM of ICR1 and mUPD7 roughly account for 45% to 50% and 5% to 10% of SRS cases, respectively.6 7 8 9 Rare cytogenetic rearrangements have also been reported in 1% to 2% of cases.4 10 11 There remain 30% to 40% of SRS cases in which the molecular mechanisms remain elusive, however.

Owing to the wide spectrum of clinical presentations of SRS, there is considerable clinical overlap with other growth retardation syndromes. At present there is no consensus for the diagnostic criteria, so diagnosing SRS is challenging. Several scoring systems have been proposed to facilitate clinical diagnosis and to guide genetic testing.7 11 12 13 14 Based on the prevalence of different molecular mechanisms, methylation study of the 11p15 region is the recommended first-tier investigation for patients with suspected SRS, and mUPD7 analysis is the second tier.14

The comprehensive clinical spectrum and molecular study of SRS have not been reported in the Chinese population. Therefore, a retrospective review that aimed to summarise the clinical and genetic findings of all SRS patients in Hong Kong was conducted. The sensitivity and specificity of different scoring systems7 11 12 13 14 in identifying Hong Kong Chinese SRS patients have also been studied.

The Clinical Genetic Service (CGS), Department of Health and the clinical genetic clinic at Queen Mary Hospital (QMH), The University of Hong Kong, are the only two tertiary genetic referral centres that provide comprehensive genetic counselling, and diagnostic and laboratory service for the Hong Kong population. Patients with a clinical suspicion of growth failure due to genetic causes or possibly SRS were referred for assessment and genetic testing.

In this review, all records of patients with suspected SRS seen at the CGS or clinical genetic clinic of QMH between January 2010 and September 2015 were retrieved from the computer database system using the key words of “Silver Russell syndrome” and “failure to thrive and growth retardation”. The clinical and laboratory data of these patients were retrospectively analysed. Patients with alternative diagnoses after assessment and genetic investigation were excluded. This study was done in accordance with the principles outlined in the Declaration of Helsinki.

Currently, there is no universal consensus on the diagnostic criteria of SRS, but the Hitchins et al’s criteria15 are the most commonly used clinically. The diagnosis of SRS in this study was made when a patient fulfilled three major, or two major and two minor criteria.

Major criteria included (1) intrauterine growth retardation/small for gestational age (<10th percentile); (2) postnatal growth with height/length <3rd percentile; (3) normal head circumference (3rd-97th percentile); and (4) limb, body, and/or facial asymmetry.

Minor criteria included (1) short arm span with normal upper-to-lower segment ratio; (2) fifth finger clinodactyly; (3) triangular facies; and (4) frontal bossing/prominent forehead.

Investigation of the methylation status and copy number change of the H19 differentially methylated region (H19 DMR) and KvDMR1 at chromosome 11p15 region was done with methylation specific–multiplex ligation-dependent probe amplification (MS-MLPA) method, using SALSA MLPA ME030-B1 BWS/RSS kit (MRC-Holland, Amsterdam, The Netherlands). Following the manufacturer’s instructions, approximately 100 ng genomic DNA was first denatured and hybridised overnight with the probe mixture supplied with the kit. The samples were then split into two portions, treated either with ligase alone or with ligase and HhaI. Polymerase chain reactions (PCR) were then performed with the reagents and primers supplied in the kit. The PCR products were separated by capillary electrophoresis (model 3130xl; Applied Biosystems, Foster City [CA], US). The electropherograms were analysed using GeneScan software (Applied Biosystems, Foster City [CA], US), and the relative peak area was calculated using the Coffalyser version 9.4 software (MRC-Holland, Amsterdam, The Netherlands).

We studied mUPD7 with eight polymorphic microsatellite markers, three on 7p and five on 7q (D7S531, D7S507, D7S2552, D7S2429, D7S2504, D7S500, D7S2442, and D7S2465), using a standard protocol. Haplotype analysis was then performed. A diagnosis of mUPD7 required evidence of exclusive maternal inheritance at two or more informative markers.

Epidemiological data, physical characteristics, growth records, and molecular findings were then collected for analysis. Clinical photographs were taken during consultation (Fig 1). In order to delineate the (epi)genotype-phenotype correlation, we divided the patients according to their (epi)genotype, namely H19 LOM, mUPD7, mosaic maternal uniparental disomy of chromosome 11 (mUPD11), or SRS of unexplained origin. The SRS of unexplained origin was defined as negative for 11p15 region epimutation and mUPD7 study. For statistical calculation, Student’s t test was used for continuous variables and Fisher’s exact test for categorical variables. Two-tailed P values were also computed. Differences were considered to be statistically significant when P≤0.05.

Three clinical scoring systems were applied to all patients referred with suspected SRS and included Netchine et al score,7 Bartholdi et al score,12 and the Birmingham score.14 An overview of the three SRS scoring systems is summarised in Table 1. Using the Hitchins et al’s criteria15 as standard in this study, the sensitivity and specificity of these three scoring systems in identifying SRS were compared.

During the study period, 83 patients with suspected SRS were referred to both genetic clinics. After clinical assessment and investigations, 54 patients had an alternative diagnosis. The remaining 29 patients were clinically diagnosed with SRS using the Hitchins et al’s criteria.15 All were Chinese. One was a prenatal case with maternal H19 duplication. Since termination of pregnancy was performed at 23 weeks of gestation, it was excluded for downstream analysis. For the remaining 28 SRS patients, their age at the end of the study (September 2015) ranged from 2 years to 22 years 9 months, with a median of 9 years 4 months. The male-to-female ratio was 9:5. Sequential MS-MLPA study on chromosome 11p15 region and mUPD7 study were performed on all SRS patients. Among the 28 live-birth SRS patients, 35.7% (n=10) had H19 LOM, 21.4% (n=6) had mUPD7, 3.6% (n=1) had mosaic mUPD11, and 39.3% (n=11) were of SRS of unexplained origin. The clinical features of the SRS cohort are summarised in Table 2. The clinical features of some molecularly confirmed SRS patients in this study and one illustrative microsatellite electropherogram in mUPD7 analysis are shown in Figure 1.

In order to study the (epi)genotype-phenotype correlation among the H19 LOM and mUPD7 groups, the clinical features were compared. There was no significant difference among the two groups (data not shown). When comparing the 28 molecularly confirmed SRS and 54 SRS of unexplained origin patients, postnatal microcephaly (P=0.01) and café-au-lait spots (P=0.05) were more common among SRS of unexplained origin, while body asymmetry (P<0.01) and limb asymmetry (P<0.01) were more common among the molecularly confirmed group.

The performance of the three clinical scoring systems namely Netchine et al score,7 Bartholdi et al score,12 and Birmingham score14 in identifying SRS in our cohort was compared. The proportion of molecularly confirmed cases in those ‘likely SRS’ and ‘unlikely SRS’ based on the scoring system are summarised in Table 3. The sensitivity and specificity among different scoring systems for identifying SRS are summarised in Table 4.

Silver-Russell syndrome is a clinically and genetically heterogeneous disorder. This is the first comprehensive clinical and epigenetic study of SRS in Hong Kong. With sequential 11p15 epimutation analysis and mUPD7 study of SRS patients in this cohort, molecular confirmation was achieved in 60.7% of cases; H19 LOM and mUPD7 accounted for 35.7% and 21.4% of the cases, respectively. Although the proportion of H19 LOM–related SRS cases was similar to the western and Japanese populations,6 7 8 9 16 the proportion of mUPD7 in our cohort was significantly higher. Nonetheless, due to the small sample size, this observation might not reflect the true ethnic-specific epigenetic alteration in the Chinese population. Further studies are necessary to confirm this difference.

In previous studies of (epi)genotype-phenotype correlation4 7 12 17 18 19 20 in SRS, patients with mUPD7 had a milder phenotype but were more likely to have developmental delay. On the contrary, patients with H19 LOM appeared to have more typical SRS features such as characteristic facial profile and body asymmetry. Such a correlation could not be demonstrated in our cohort. When comparing the molecularly confirmed and SRS of unexplained origin groups, postnatal microcephaly and café-au-lait spots were more common in the group of SRS of unexplained origin, while body/limb asymmetry was more common in the molecularly confirmed group. This observation has also been reported in Japanese SRS patients.16 This might be due to the greater clinical and genetic heterogeneity in the molecularly negative SRS.

Although SRS has been extensively studied, there remains no universal consensus on the clinical diagnostic criteria. Hitchins et al’s criteria15 are currently the most commonly used. In order to facilitate the clinical diagnosis, several additional scoring systems have been proposed which include the Netchine et al,7 Bartholdi et al,12 and Birmingham scores.14 Each of them has its advantages and limitations. The major caveats of those scoring systems include relative subjectivity of clinical signs, and time-dependent and evolving clinical features. The heterogeneity of clinical manifestations also limits their application. In order to validate these scoring systems, several studies have been performed to evaluate their accuracy in predicting the molecular genetic testing result.14 21 We also evaluated the performance of these three scoring systems in this Chinese cohort. All three scoring systems are 100% specific in diagnosing SRS, but the sensitivity for Netchine et al score,7 Bartholdi et al score,12 and Birmingham score14 is 75%, 53.6%, and 71.4%, respectively when compared with Hitchins et al’s criteria.15 This suggests that Hitchins et al’s criteria15 remain the most sensitive diagnostic criteria for SRS when used clinically.

The management of SRS is challenging and requires multidisciplinary input. Growth hormone (GH) treatment is the current recommended therapy for children with small for gestational age without spontaneous catch-up growth and those with GH deficiency. In SRS, abnormalities in spontaneous GH secretion and subnormal responses to provocative GH stimulation have been well reported.20 The proposed mechanism is dysregulation of the growth factors and its major binding protein,4 particularly in the H19 LOM group. Besides, SRS patients are expected to have poor catch-up growth. Nonetheless, GH therapy is not a universal standard treatment for SRS. In Hong Kong, the indications for GH therapy under Hospital Authority guidelines do not include SRS22 without GH response abnormalities. In our cohort, only three patients who had a suboptimal GH provocative stimulation test are currently receiving GH treatment. The long-term outcome is not yet known.

Although tissue-specific epigenetic manifestation has been reported in SRS,23 mosaic genetic or epigenetic alteration is uncommon.24 We have one patient with mUPD11 confirmed by molecular testing with peripheral blood and buccal swab samples. Mosaicism should be considered when a patient has typical SRS phenotype but negative routine testing. Testing of other tissue should be pursued so as to provide an accurate molecular diagnosis that can guide subsequent genetic counselling and clinical management.

Finally, upon review of the literature, it is well known that gain of function of the CDKN1C gene25 and maternal UPD14 (Temple syndrome)26 27 can result in a phenotype mimicking SRS. There are also other syndromic growth retardation disorders with many overlapping clinical features with those of SRS, such as mulibrey nanism and 3-M syndrome.28 29 Therefore, with the latest understanding of the molecular pathogenetic mechanisms of SRS, together with evidence21 30 31 and results from this study, we propose the diagnostic algorithm for Chinese SRS patients as depicted in Figure 2. All clinically suspected SRS patients should be assessed by a clinical geneticist. Although the Netchine et al score,7 Bartholdi et al score,12 and Birmingham score14 are highly specific, they are less sensitive than the Hitchins et al’s criteria15 for diagnosing SRS in our Chinese cohort. Therefore, the Hitchins et al’s criteria15 should be used clinically to classify those suspected SRS patients into ‘likely’ or ‘unlikely’ SRS. For those ‘likely SRS’ patients, sequential 11p15 region methylation study and mUPD7 analysis should be performed because 11p15 region epigenetic alteration is more prevalent than mUPD7 in SRS. For those molecularly unconfirmed SRS, further testing for other SRS-like syndromes including Temple syndrome or CDKN1C-related disorder should be pursued if indicated.

This 5-year review is the first territory-wide study of Chinese SRS patients in Hong Kong. It showed that the clinical features and underlying epigenetic mechanisms of Chinese SRS are similar to those of other western populations. Early diagnosis and multidisciplinary management are important for managing SRS patients. Vigilant clinical suspicion with confirmation by molecular testing is essential. Based on the current evidence and performance evaluation of different clinical scoring systems, a comprehensive diagnostic algorithm is proposed. We hope that with an increase in understanding of the underlying pathophysiology and the (epi)genotype-phenotype correlation in Chinese SRS patients, the quality of medical care will be greatly improved in the near future.

We thank all the paediatricians and physicians who have referred their SRS patients to our service and QMH. We are also grateful to all the laboratory staff in CGS for their technical support. This work in HKU is supported by HKU small project funding and The Society for the Relief of Disabled Children in Hong Kong.

All authors have disclosed no conflicts of interest.

1. Silver HK, Kiyasu W, George J, Deamer WC. Syndrome of congenital hemihypertrophy, shortness of stature, and elevated urinary gonadotropins. Pediatrics 1953;12:368-76.

2. Russell A. A syndrome of intra-uterine dwarfism recognizable at birth with cranio-facial dysostosis, disproportionately short arms, and other anomalies (5 examples). Proc R Soc Med 1954;47:1040-4.

3. Wollmann HA, Kirchner T, Enders H, Preece MA, Ranke MB. Growth and symptoms in Silver-Russell syndrome: review on the basis of 386 patients. Eur J Pediatr 1995;154:958-68. Crossref

4. Wakeling EL, Amero SA, Alders M, et al. Epigenotype-phenotype correlations in Silver-Russell syndrome. J Med Genet 2010;47:760-8. Crossref

5. Christoforidis A, Maniadaki I, Stanhope R. Managing children with Russell-Silver syndrome: more than just growth hormone treatment? J Pediatr Endocrinol Metab 2005;18:651-2. Crossref

6. Kotzot D, Schmitt S, Bernasconi F, et al. Uniparental disomy 7 in Silver-Russell syndrome and primordial growth retardation. Hum Mol Genet 1995;4:583-7. Crossref

7. Netchine I, Rossignol S, Dufourg MN, et al. 11p15 Imprinting center region 1 loss of methylation is a common and specific cause of typical Russell-Silver syndrome: clinical scoring system and epigenetic-phenotypic correlations. J Clin Endocrinol Metab 2007;92:3148-54. Crossref

8. Gicquel C, Rossignol S, Cabrol S, et al. Epimutation of the telomeric imprinting center region on chromosome 11p15 in Silver-Russell syndrome. Nat Genet 2005;37:1003-7. Crossref

9. Schönherr N, Meyer E, Eggermann K, Ranke MB, Wollmann HA, Eggermann T. (Epi)mutations in 11p15 significantly contribute to Silver-Russell syndrome: but are they generally involved in growth retardation? Eur J Med Genet 2006;49:414-8. Crossref

10. Azzi S, Abi Habib W, Netchine I. Beckwith-Wiedemann and Russell-Silver Syndromes: from new molecular insights to the comprehension of imprinting regulation. Curr Opin Endocrinol Diabetes Obes 2014;21:30-8. Crossref

11. Price SM, Stanhope R, Garrett C, Preece MA, Trembath RC. The spectrum of Silver-Russell syndrome: a clinical and molecular genetic study and new diagnostic criteria. J Med Genet 1999;36:837-42.

12. Bartholdi D, Krajewska-Walasek M, Ounap K, et al. Epigenetic mutations of the imprinted IGF2-H19 domain in Silver-Russell syndrome (SRS): results from a large cohort of patients with SRS and SRS-like phenotypes. J Med Genet 2009;46:192-7. Crossref

13. Eggermann T, Gonzalez D, Spengler S, Arslan-Kirchner M, Binder G, Schönherr N. Broad clinical spectrum in Silver-Russell syndrome and consequences for genetic testing in growth retardation. Pediatrics 2009;123:e929-31. Crossref

14. Dias RP, Nightingale P, Hardy C, et al. Comparison of the clinical scoring systems in Silver-Russell syndrome and development of modified diagnostic criteria to guide molecular genetic testing. J Med Genet 2013;50:635-9. Crossref

15. Hitchins MP, Stanier P, Preece MA, Moore GE. Silver-Russell syndrome: a dissection of the genetic aetiology and candidate chromosomal regions. J Med Genet 2001;38:810-9. Crossref

16. Fuke T, Mizuno S, Nagai T, et al. Molecular and clinical studies in 138 Japanese patients with Silver-Russell syndrome. PLoS One 2013;8:e60105. Crossref

17. Bliek J, Terhal P, van den Bogaard MJ, et al. Hypomethylation of the H19 gene causes not only Silver-Russell syndrome (SRS) but also isolated asymmetry or an SRS-like phenotype. Am J Hum Genet 2006;78:604-14. Crossref

18. Bruce S, Hannula-Jouppi K, Peltonen J, Kere J, Lipsanen-Nyman M. Clinically distinct epigenetic subgroups in Silver-Russell syndrome: the degree of H19 hypomethylation associates with phenotype severity and genital and skeletal anomalies. J Clin Endocrinol Metab 2009;94:579-87. Crossref

19. Kotzot D. Maternal uniparental disomy 7 and Silver-Russell syndrome—clinical update and comparison with other subgroups. Eur J Med Genet 2008;51:444-51. Crossref

20. Binder G, Seidel AK, Martin DD, et al. The endocrine phenotype in Silver-Russell syndrome is defined by the underlying epigenetic alteration. J Clin Endocrinol Metab 2008;93:1402-7. Crossref

21. Azzi S, Salem J, Thibaud N, et al. A prospective study validating a clinical scoring system and demonstrating phenotypical-genotypical correlations in Silver-Russell syndrome. J Med Genet 2015;52:446-53. Crossref

22. But WM, Huen KF, Lee CY, Lam YY, Tse WY, Yu CM. An update on the indications of growth hormone treatment under Hospital Authority in Hong Kong. Hong Kong J Paediatr 2012;17:208-16.

23. Azzi S, Blaise A, Steunou V, et al. Complex tissue-specific epigenotypes in Russell-Silver Syndrome associated with 11p15 ICR1 hypomethylation. Hum Mutat 2014;35:1211-20. Crossref

24. Bullman H, Lever M, Robinson DO, Mackay DJ, Holder SE, Wakeling EL. Mosaic maternal uniparental disomy of chromosome 11 in a patient with Silver-Russell syndrome. J Med Genet 2008;45:396-9. Crossref

25. Brioude F, Oliver-Petit I, Blaise A, et al. CDKN1C mutation affecting the PCNA-binding domain as a cause of familial Russell Silver syndrome. J Med Genet 2013;50:823-30. Crossref

26. Ioannides Y, Lokulo-Sodipe K, Mackay DJ, Davies JH, Temple IK. Temple syndrome: improving the recognition of an underdiagnosed chromosome 14 imprinting disorder: an analysis of 51 published cases. J Med Genet 2014;51:495-501. Crossref

27. Kagami M, Mizuno S, Matsubara K, et al. Epimutations of the IG-DMR and the MEG3-DMR at the 14q32.2 imprinted region in two patients with Silver-Russell Syndrome–compatible phenotype. Eur J Hum Genet 2015;23:1062-7. Crossref

28. Hämäläinen RH, Mowat D, Gabbett MT, O’brien TA, Kallijärvi J, Lehesjoki AE. Wilms’ tumor and novel TRIM37 mutations in an Australian patient with mulibrey nanism. Clin Genet 2006;70:473-9. Crossref

29. van der Wal G, Otten BJ, Brunner HG, van der Burgt I. 3-M syndrome: description of six new patients with review of the literature. Clin Dysmorphol 2001;10:241-52. Crossref

30. Scott RH, Douglas J, Baskcomb L, et al. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) robustly detects and distinguishes 11p15 abnormalities associated with overgrowth and growth retardation. J Med Genet 2008;45:106-13. Crossref

31. Spengler S, Begemann M, Ortiz Brüchle N, et al. Molecular karyotyping as a relevant diagnostic tool in children with growth retardation with Silver-Russell features. J Pediatr 2012;161:933-42. Crossref

Violence, which has been ever present throughout the history of humanity, is defined as a threat or application of possessed power or strength towards another person, self, a group, or a community in order to cause injury and/or loss.1 The World Health Organization defines violence as “physical assault, homicide, verbal assault, emotional, sexual or racial harassment”.2

Workplace violence is defined as “abuse or attacks by one or more people on an employee within the workplace”.3 The health care field, which encompasses a wide range of employees, is among those in which workplace violence is common.4 Violence in the health care field is defined as “risk to a health worker due to threatening behaviour, verbal threats, physical assault and sexual assault committed by patients, patient relatives, or any other person”.3

According to the 2002 Workplace Violence in the Health Sector report, 25% of all violent incidents occurred in the health care sector.5 A study conducted in the United States determined that the risk of being subjected to violence is 16 times higher in the health care sector relative to other service sectors.6 Within the health care field, the department that is most frequently exposed to violence is the emergency department (ED).3 7 8 9 In this context, verbal and physical attacks by dissatisfied patients and their relatives are at the forefront.10 11

In this study we aimed to determine the extent of violence towards ED employees, analyse the attitude of the staff exposed to violence, and propose possible solutions.

This cross-sectional study was conducted in the EDs of Şevket Yilmaz Training and Research Hospital and Sakarya University between 1 July and 15 August 2012. Employees of ED—including doctors, nurses, health care officials, Emergency Medical Technicians (EMT), secretaries, laboratory technicians, radiology technicians, and security and cleaning staff—were included in the study. The questionnaire was prepared in accordance with previous publications3 10 11 and distributed to participants. All study participants were provided with information regarding the objectives of the study and were given instructions for completing the form. Of the 437 ED employees working in the two hospitals, 323 (73.9%) agreed to participate in the study and returned a completed questionnaire.

In addition to demographic information, the questionnaire contained questions about the number of violent incidents to which the individual had been subjected to, the type of violence, and whether the subject reported the incident or the reason for not reporting. Additional questions concerned a description of the person(s) responsible for the violence, the estimated age of the person(s) responsible for the violence, and the severity of the violence. We also asked participants about their attitude following the violent incident and suggestions for reducing violence in the ED.

This study was conducted in accordance with the principles of the 2008 Helsinki Declaration. The data were analysed using the Statistical Package for the Social Sciences (Windows version 15.0; SPSS Inc, Chicago [IL], US). Both proportions and mean ± standard deviation were used to represent the results. The Student’s t test, Pearson’s Chi squared test, and the Monte Carlo Chi squared tests were used to evaluate observed differences between groups and a P value of <0.05 was considered to represent a statistically significant difference.

Among the 323 participants included in the study, 189 (58.5%) were male and 134 (41.5%) were female. The mean age of the male participants was 31.5 ± 6.5 years (range, 18-55 years) and that of the female participants was 32.0 ± 6.9 years (range, 20-52 years). There was no significant difference in the age distribution between the male and female participants (P=0.476).

When participants were asked if they had ever been exposed to verbal or physical violence in the workplace during the course of their career, 239 (74.0%) indicated that they had been subjected to one or the other, and 57 (17.6%) reported being subjected to both verbal and physical violence. Among the participants who were subjected to violence, 162 (67.8%) reported being the victim of more than five violent incidents (Table 1).

The frequency of exposure to violence and the frequency of exposure to more than five violent incidents were similar for both men and women (P=0.185 and 0.104, respectively). Nonetheless, 25.9% of men reported both verbal and physical violence compared with only 6.0% of women, suggesting that the incidence of verbal and physical violence against men was greater than that against women (P<0.001) [Table 1].

We investigated the frequency of exposure to violence and the reported incidence of violence among various occupation groups (Table 2). The prevalence of exposure to violence was the highest among health care officials, EMTs, doctors, and security staff (P<0.001). In addition, only 102 (42.7%) out of 239 participants reported these violent incidents. It is notable that although the rate of incident reporting was 100% among security staff, none of the laboratory technicians reported the violent incidents (P<0.001).

A total of 43 (31.4%) out of the 137 study participants who had been exposed to violence but had not reported the incident provided reasons (Table 3). The most common reason for not notifying the authorities was the perception that “no resolution will be reached”. Other important reasons included the heavy workload, not wanting to deal with the legal process, disregarding verbal attacks, understanding/sympathising with the emotions of patients and their relatives, fear of the threat from patients and their relatives, and not knowing how and where to report such incidents.

A total of 248 participants responded to a question regarding the identity of the person who was to blame for the violence in ED in general (not their own experiences). Accordingly, 65.3% (n=162) stated that the patient’s relatives were responsible, 27.0% (n=67) stated that both the patients and their relatives were responsible, and 5.2% (n=13) placed sole responsibility on the patients. Six (2.4%) participants stated that they had been subjected to violence from other health care professionals.

When we asked individuals to estimate the age of the person(s) causing the violence that they had experienced, respondents who were exposed to multiple violent incidents answered this question by selecting multiple options and a total of 405 answers were obtained. As shown in Table 4, the majority (71.4%) of people responsible for violent incidents were young patients and patient relatives between the ages of 18 and 39 years.

When participants who were exposed to violence were asked who caused the violent incident, three (1.3%) participants stated that they themselves were responsible, five (2.1%) indicated that both sides were responsible, and the remaining 231 (96.7%) held the attacker responsible.

Participants were asked “What do you think is the reason for the violence?”. A total of 181 (56.0%) participants responded to this question. Some participants indicated more than one reason and a total of 188 answers were obtained. The top 10 most common responses to this question are given in descending order of frequency in Table 5. The most common cause of violence was ignorance and lack of education of patients and their relatives (28.7%), followed by the impatient attitudes and demanding priorities (23.4%) and the heavy workload and prolonged waiting time (10.6%).

Participants were asked “How do you think violence against health care workers can be reduced?”. Some participants indicated more than one reason and a total of 509 answers were obtained. They considered the most important steps suggested to reduce violence against ED employees were the enactment of deterrent legislation (42.6%), increased security measures in hospitals (28.5%), and improved public education (16.7%) [Table 5].

Participants were asked about their attitude after experiencing violence. Some respondents gave more than one answer and a total of 498 answers were obtained. There were 27.1% of participants who did not enjoy working in their current profession, 25.7% wanted to work in non–health care field, and 21.5% did not want to work in the ED (Table 6).

A total of 96.3% (n=311) of participants answered “Yes” to the question “Do you think that the violence against health care workers has increased in recent years?” Moreover, 90.7% (n=293) of the participants answered “Yes” to the question “Do news reports regarding violence against health care workers affect you?”. Then, when participants were asked “How does the news affect you?”, 64.7% (n=209) reported that they were “sad”, 44.3% (n=143) said they were “angry”, and 18.9% (n=61) said they were “scared”.

When participants were asked “Are there sufficient security measures in your workplace?”, only 66 (20.4%) participants gave a positive response, while 257 (79.6%) responded negatively. Among the 41 participants working as security staff, 33 (80.5%) found the safety measures inadequate. Thus, both the security staff and the general employee population agreed that hospital security was inadequate.

Workplace violence is the most prevalent in the health care sector.4 The ED is the health care unit with the highest frequency of exposure to violence.3 7 8 9 According to several previous studies, the proportion of health care professionals who report prior exposure to violence in the workplace ranges from 45% to 67.6%.3 8 12 13 14 The rate of violence against ED employees (79%-99%), however, is higher than the average for the health care field.15 16 17

Emergency services are high-risk areas for patients and staff with regard to workplace violence18 19 20 21; 24-hour accessibility, a high-stress environment, and the apparent lack of trained security personnel are underlying factors.22 Workplace violence negatively affects the morale of health care workers and negatively affects the health and effectiveness of presentation.23 24 25 26

Our study was conducted among ED employees of two different hospitals. We investigated the rate of exposure to verbal or physical violence. Among the participants, 239 (74.0%) stated that they had been subjected to exposure to violence, and 57 (17.6%) reported having been exposed to both verbal and physical violence. A study in Turkey found that among ED employees, including nurses, in the İzmir province of Turkey, 98.5% of respondents had been subjected to verbal violence and 19.7% were exposed to physical violence.16 In another study conducted in Turkey, 88.6% of ED employees were subjected to verbal violence and 49.4% reported having been the victim of physical violence.17

In the present study, the rate of exposure to violence by profession was 95.7% among health care officials/EMTs, 90.7% among doctors, and 80.5% among security personnel. According to Ayrancı et al,3 exposure to violence was most common among practitioners (67.6%) and nurses (58.4%). In another study, Alçelik et al27 reported that nurses were exposed to violence 3 times more often than other health care professionals. In the present study, the frequency of exposure to violence among nurses was 62.7%, which is lower than that in other professional groups.

In the present study, the estimated age distribution of patients and patient relatives responsible for violent incidents showed that the majority (71.4%) were between 18 and 39 years of age. Other studies have reported that individuals prone to violence are generally younger than 30 years.28

Health care workers are often subjected to verbal and physical attacks from patients and their relatives who are dissatisfied with the services provided.10 11 In the present study, the most common cause of violence was the lack of education and ignorance of the patients and their relatives. Heavy workload was identified as another cause of workplace violence. Factors such as patient stress and anxiety regarding their condition, high expectations of the patients and their relatives, lack of effective institutional and legal arrangements aimed at preventing violence, and the failure to effectively document the extent of workplace violence contribute to the high frequency of violence.12 There are several factors that increase the risk of violence in health care institutions, including 24-hour service, long waiting time for patients, poor access to health care services, heavy workload, limited staff, inadequate employee training, and lack of security personnel.29 30

Previous studies conducted in Turkey revealed that 60% of ED employees who were exposed to violence did not report the incident. Among the reasons for not reporting was a lack of confidence in health care and executive leadership as well as the justice system.12 In the present study, the incident reporting rate was also low (42.7%) and the most important reason (34.9%) for not reporting was the perception that “no resolution will be reached”. Indeed, a study found that there were no repercussions for the attacker in 77% of instances.12 This suggests the perception that “no resolution will be reached” is a valid one.

A heavy workload consumes the energy of employees and reduces their ability to empathise with patients and tolerate violent situations. Sometimes verbal or physical conflicts may arise between a stressed patient who may be subject to long waiting times and exhausted and stressed health care workers. Training regarding communication with patients helps health care professionals to avoid these problems.31 Effective communication alone, however, is not sufficient and additional steps must be taken to reduce waiting time of patients. Previous studies have indicated that the most important reason for patient dissatisfaction in the ED is the waiting time.32 33 Yet, the most important reason for long waiting times is the heavy workload caused, in part, by the discourteous attitude of patients and their relatives. Studies have also shown that more than half of patients who present to the ED are not ‘emergency patients’.34 35 36 Further education regarding the definition of “emergency” and the practice of effective triage may reduce the heavy workload in the ED and associated violent incidents.

One previous study reported that verbal and physical attacks by patients and their relatives are the most important factors contributing to stress among ED employees.37 Consistent exposure to high-stress conditions resulting from exposure to verbal and physical violence results in both physical and mental exhaustion. As a result, a situation known commonly as ‘burnout syndrome’ emerges.38 39 The burnout syndrome is defined as holding a negative view of current events, frequent despair, and lost productivity and motivation.40 Reluctance among physicians to work in the ED is one consequence of burnout syndrome.41 In the present study, among the participants who were subjected to violence, 21.5% indicated that they wanted to work in a department other than the ED, while 25.7% stated a desire to work outside the health care field. In a study conducted in Canada, 18% of participants who had been exposed to violence stated that they did not want to work in the ED, and 38% wanted to work outside the health care field.9 Others indicated that they had quitted their jobs because of workplace stress.9 In the present study, 10.4% of ED employees stated that they were afraid of patients and their relatives. In the same Canadian study, 73% of respondents stated that after experiencing violence they were afraid of patients.9 In our study, 96.3% of respondents thought that there had been an increase in violence against ED health care workers in recent years. Moreover, 79.6% of respondents stated that the safety measures in their institutions were insufficient. The participants in the present study suggested that the preparation of deterrent legislation, increased security measures, and efforts to better educate the general population regarding the appropriate use of ED resources will help to reduce violence against health care workers.

The study was carried out in only two hospitals in Turkey that may not be representative of all hospitals. In addition, participants could decide whether or not to answer all questions and some questionnaires were incomplete. The response rate was only 74% and this might give rise to self-selection bias, that is, those who did not respond may have had a higher (or lower) exposure to violence than those who responded. Hence, the various percentages reported in this paper might be over- or under-estimated.

The results of the current study as well as those of earlier studies indicate that the prevalence of violence against ED employees is high. Factors such as patient and stress of health care provider, prolonged waiting times due to overcrowding in the ED, negative attitude of discourteous patients and their relatives, insufficient security measures, and the lack of sufficiently dissuasive legal regulations may contribute to increased violence in the ED. These factors in turn increase stress among ED employees, reduce job satisfaction, and lower the quality of services provided. Measures to decrease the workload in the ED and shorten waiting time of patients, the adoption of legal policies that deter violent behaviour, and increased security measures in health care facilities should be reassessed. Steps should be taken to educate the public in order to reduce violence against health care workers.

All authors have disclosed no conflicts of interest.

1. Kocacik F. On violence [in Turkish]. Cumhuriyet Univ J Econ Adm Sci 2001;2:1-2.

2. Violence and injury prevention. Available from: http://www.who.int/violence_injury_prevention/violence/activities/workplace/documents/en/index.html. Accessed Nov 2012.

3. Ayrancı Ü, Yenilmez Ç, Günay Y, Kaptanoğlu C. The frequency of being exposed to violence in the various health institutions and health profession groups. Anatol J Psychiatry 2002;3:147-54.

4. Wells J, Bowers L. How prevalent is violence towards nurses working in general hospitals in the UK? J Adv Nurs 2002;39:230-40. Crossref

5. Workplace violence in the health sector. Framework guidelines for addressing workplace violence in the health sector. Available from: http://www.ilo.org/wcmsp5/groups/public/---ed_dialogue/---sector/documents/publication/wcms_160912.pdf. Accessed Nov 2012.

6. Kingma M. Workplace violence in the health sector: a problem of epidemic proportion. Int Nurs Rev 2001;48:129-30. Crossref

7. Gülalp B, Karcıoğlu, Köseoğlu Z, Sari A. Dangers faced by emergency staff: experience in urban centers in southern Turkey. Ulus Travma Acil Cerrahi Derg 2009;15:239-42.

8. Lau J, Magarey J, McCutcheon H. Violence in the emergency department: a literature review. Aust Emerg Nurs J 2004;7:27-37. Crossref

9. Fernandes CM, Bouthillette F, Raboud JM, et al. Violence in the emergency department: a survey of health care workers. CMAJ 1999;161:1245-8.

10. Yanci H, Boz B, Demirkiran Ö, Kiliççioğlu B, Yağmur F. Medical personal subjected to the violence in emergency department—enquiry study. Turk J Emerg Med 2003;3:16-20.

11. Sucu G, Cebeci F, Karazeybek E. Violence by patient and relatives against emergency service personnel. Turk J Emerg Med 2007;7:156-62.

12. Çamci O, Kutlu Y. Determination of workplace violence toward health workers in Kocaeli. J Psychiatr Nurs 2011;2:9-16.

13. Stirling G, Higgins JE, Cooke MW. Violence in A&E departments: a systematic review of the literature. Accid Emerg Nurs 2001;9:77-85. Crossref

14. Sönmez M, Karaoğlu L, Egri M, Genç MF, Günes G, Pehlivan E. Prevalence of workplace violence against health staff in Malatya. Bitlis Eren Univ J Sci Technol 2013;3:26-31.

15. Stene J, Larson E, Levy M, Dohlman M. Workplace violence in the emergency department: giving staff the tools and support to report. Perm J 2015;19:e113-7. Crossref

16. Senuzun Ergün F, Karadakovan A. Violence towards nursing staff in emergency departments in one Turkish city. Int Nurs Rev 2005;52:154-60. Crossref

17. Boz B, Acar K, Ergin A, et al. Violence toward health care workers in emergency departments in Denizli, Turkey. Adv Ther 2006;23:364-9. Crossref

18. Joa TS, Morken T. Violence towards personnel in out-of-hours primary care: a cross-sectional study. Scand J Prim Health Care 2012;30:55-60. Crossref

19. Magnavita N, Heponiemi T. Violence towards health care workers in a Public Health Care Facility in Italy: a repeated cross-sectional study. BMC Health Serv Res 2012;12:108. Crossref

20. Arimatsu M, Wada K, Yoshikawa T, et al. An epidemiological study of work-related violence experienced by physicians who graduated from a medical school in Japan. J Occup Health 2008;50:357-61. Crossref

21. Taylor JL, Rew L. A systematic review of the literature: workplace violence in the emergency department. J Clin Nurs 2011;20:1072-85. Crossref

22. Gacki-Smith J, Juarez AM, Boyett L, Homeyer C, Robinson L, MacLean SL. Violence against nurses working in US emergency departments. J Nurs Adm 2009;39:340-9. Crossref

23. Kowalenko T, Gates D, Gillespie GL, Succop P, Mentzel TK. Prospective study of violence against ED workers. Am J Emerg Med 2013;31:197-205. Crossref

24. Position statement: violence in the emergency care setting. Available from: https://www.ena.org/government/State/Documents/ENAWorkplaceViolencePS.pdf. Accessed Nov 2012.

25. Workplace violence. Washington, DC: United States Department of Labor; 2013. Available from: http://www.osha.gov/SLTC/workplaceviolence/index.html. Accessed Nov 2012.

26. Adib SM, Al-Shatti AK, Kamal S, El-Gerges N, Al-Raqem M. Violence against nurses in healthcare facilities in Kuwait. Int J Nurs Stud 2002;39:469-78. Crossref

27. Alçelik A, Deniz F, Yeşildal N, Mayda AS, Ayakta Şerifi B. Health survey and life habits of nurses who work at the medical faculty hospital at AIBU [in Turkish]. TAF Prev Med Bull 2005;4:55-65.

28. Young GP. The agitated patient in the emergency department. Emerg Med Clin North Am 1987;5:765-81.

29. Stathopoulou HG. Violence and aggression towards health care professionals. Health Sci J 2007;2:1-7.

30. Hoag-Apel CM. Violence in the emergency department. Nurs Manage 1998;29:60,63.

31. Yardan T, Eden AO, Baydın A, Genç S, Gönüllü H. Communication with relatives of the patients in emergency department. Eurasian J Emerg Med 2008;7:9-13.

32. Al B, Yıldırım C, Togun İ, et al. Factors that affect patient satisfaction in emergency department. Eurasian J Emerg Med 2009;8:39-44.

33. Yiğit Ö, Oktay C, Bacakoğlu G. Analysis of the patient satisfaction forms about Emergency Department services at Akdeniz University Hospital. Turk J Emerg Med 2010;10:181-6.

34. Kiliçaslan İ, Bozan H, Oktay C, Göksu E. Demographic properties of patients presenting to the emergency department in Turkey. Turk J Emerg Med 2005;5:5-13.

35. Ersel M, Karcıoğlu Ö, Yanturali S, Yörüktümen A, Sever M, Tunç MA. Emergency Department utilization characteristics and evaluation for patient visit appropriateness from the patients’ and physicians’ point of view. Turk J Emerg Med 2006;6:25-35.

36. Aydin T, Aydın ŞA, Köksal Ö, Özdemir F, Kulaç S, Bulut M. Evaluation of features of patients attending the Emergency Department of Uludağ University Medicine Faculty Hospital and emergency department practices. Eurasian J Emerg Med 2010;9:163-8. Crossref

37. Kalemoglu M, Keskin O. Evaluation of stress factors and burnout in the emergency department staff [in Turkish]. Ulus Travma Derg 2002;8:215-9.

38. Ferns T, Stacey C, Cork A. Violence and aggression in the emergency department: Factors impinging on nursing research. Accid Emerg Nurs 2006;14:49-55. Crossref

39. Keser Özcan N, Bilgin H. Violence towards healthcare workers in Turkey: A systematic review [in Turkish]. Turkiye Klinikleri J Med Sci 2011;31:1442-56. Crossref

40. Maslach C. Burned-out. Hum Behav 1976;5:16-22.

41. Dwyer BJ. Surviving the 10-year ache: emergency practice burnout. Emerg Med Rep 1991;23:S1-8.

Advances in medical management now enable children with developmental disabilities (DD) who may previously have died to live well into adulthood.1 Such disabilities are defined as any condition that is present before the age of 22 years and due to physical or cognitive impairment or a combination of both that significantly affects self-care, receptive and expressive language, mobility, learning, independent living, or the economic independence of the individual.2 The transition from adolescence to adulthood is a critical period for all young people.3 In a clinical context, adult transition is “the purposeful, planned movement of adolescents and young adults with chronic physical and medical conditions from child-centered to adult-oriented health-care systems”.4 In 2001, a consensus statement with guidelines was endorsed to ensure adolescents with DD, who depend on coordinated health care services, make a smooth transition to the adult health care system in order to receive the services that they need in developed countries such as the United States.5

Researchers have identified needs and factors necessary for the successful transition of adolescents with DD.6 7 From the adolescent’s perspective, barriers to success include their dependence on others, reduced treatment time and access to specialists in the adult health service, lack of information about transition, and lack of involvement in the decision-making process. Parents of adolescents with DD were reluctant or confused about changing responsibilities during the transition period. The majority of challenges came from the service systems and included unclear eligibility criteria and procedures, limited time and lack of carer training, fragmented adult health service provision, lack of communication between service providers, and inaccessibility to resources including information.6 7

Based on the 2015 census of ‘Persons with disabilities and chronic diseases in Hong Kong’ from the Hong Kong Census and Statistics Department, there were 22 100 (3.8%) people with disability (excluding cognitive impairment) aged between 15 and 29 years, ie who were transitioning from the paediatric to adult health service.8 According to the Hospital Authority, Hong Kong, all public hospitals, and specialist and general out-patient clinics are organised into seven hospital clusters based on geographical location.9 The Duchess of Kent Children’s Hospital (DKCH) is a tertiary centre that provides specialised services for children with orthopaedic problems, spinal deformities, cerebral palsy and neurodevelopmental disorders, and neurological and degenerative diseases. Unlike overseas health care, there is no children’s hospital in Hong Kong that provides an acute health service. All paediatric patients go to the same hospital as adult patients but are triaged into the paediatric section for management by both in-patient and out-patient services. The specialised out-patient clinic list under each hospital cluster varies. Children with DD might receive services from general paediatrics clinic, a cerebral palsy clinic, Down’s clinic, behavioural clinic, or paediatric neurology out-patient clinic. Once a child reaches the age of 18 years, they are referred to the adult section of the same hospital for continued care. They will be followed up in neurology or movement disorder clinics, where other patients with adult-onset neurological conditions or movement disorders, such as stroke, Parkinson’s disease, multiple sclerosis are followed up. There is no separate specialised clinic for complex child-onset DD.10

Although adult transition for adolescents with DD has been recognised as a crucial area in health care overseas, it is an under-developed service in Hong Kong.11 A local study found that there is a service gap in adult transition for young people with chronic medical conditions, such as asthma, diabetes, and epilepsy. Training and education are urgently required for both service providers and young people with chronic health conditions and their families.11 It is unclear if the challenges and barriers identified in overseas literature6 7 are applicable to Hong Kong, where the paediatric and adult health services, especially the medical services, are located in the same building. At present, no study has been conducted with adolescents with DD and their families in Hong Kong about the issues they face during clinical transition. As a start, in this pilot study, we aimed to explore the acceptance of clinical transition and identify the main barriers to successful clinical transition for adolescents with DD and their caregivers in Hong Kong.

A survey study was conducted on a convenience sample of adolescents and/or their caregivers, who were recruited from two special high schools (Hong Kong Red Cross John F Kennedy Centre [JFK] and Haven of Hope Sunnyside School [HOH]) in Hong Kong. Students from JFK have primarily physical and multiple disabilities including cerebral palsy or muscular dystrophy and those from HOH have severe cognitive impairment. Both schools provide rehabilitation services on site including physiotherapy, occupational therapy, speech therapy, nursing support, and family support via the school social workers. The medical out-patient services for the students fall under different hospital clusters, depending on where the students’ families live. The parents are responsible for taking their adolescent children for medical review. As there was no previous study on which basis to calculate the required sample size and as a pilot study, we aimed to recruit 10 adolescents and their parents/caregivers in each school.

The inclusion criteria of the adolescents were: (1) aged 16 to 19 years and (2) a diagnosis of DD. All participating adolescents and/or their parents or legal guardians gave written informed consent before the survey. For adolescents with severe cognitive impairment, consent was sought from their parents as proxy and only their parents participated in the survey. This pilot study was approved by the Human Subjects Ethics Sub-committee of the Hong Kong Polytechnic University.

A specific questionnaire was developed for this pilot study to collect information relative to: (1) demographic characteristics of the participants; (2) whether or not the study participants were aware of the transition and the information source(s); (3) if the study participants were willing to transition to the adult health service and the underlying reasons; (4) for those who had transitioned, if they were satisfied with the adult health service and the underlying reasons; and (5) the opinion of the study participants of the clinical transition service. As a pioneer pilot study, health service included both medical and rehabilitation services and the study aimed to explore the general issues faced by this group of adolescents and their families during clinical transition. Lastly, as we predicted that the competency level of the adolescents and their caregivers in managing their disabilities might influence their perception of clinical transition, information about their self-rated competency level was also collected. Questions in the latter part were based on information from the Adolescent Transition Care Assessment Tool and were designed to assist health care professionals to provide a better transition for adolescents with chronic illness.12 The whole survey was administered by interviewers for the study adolescents and/or their caregivers separately in Cantonese. All interviews were recorded for data analyses.

The survey comprised closed- and open-ended questions. The closed-ended questions were designed to require a dichotomous answer, ie ‘yes’ or ‘no’, or an answer from a set of choices. For example, when asked about the sources of information about clinical transition, the study participants could choose their answers from a list of professionals such as paediatricians, social workers, physiotherapists, and school teachers. The open-ended questions focused on the reasons for an earlier response. For example, when asked if they wished to move to the adult health service, the individual would first answer ‘yes’ or ‘no’, then give their reasons. For the questions about self-perceived competency level, study participants read a number of statements (8 for the adolescents and 14 for parents) and indicated how much they agreed with the statement using a Likert-scale from ‘strongly disagree’ to ‘strongly agree’.

Descriptive statistics—including mean, median, standard deviation, or quartiles—were used to analyse the responses to the closed-ended questions. Discussion of the open-ended questions was transcribed and summarised by five team members (CLC, KHF, KHWF, LKL, and TCLT). The content was analysed and themes were identified independently by two other team members (TWP and WLSC). These themes were discussed and a consensus reached by all team members.

Thirteen potential families were approached at the JFK via the physiotherapist of the school anticipating possible refusal by some. All the students and their parents agreed to participate, so all were included. Ten families were approached at the HOH via the social worker at the school but one parent declined the offer and no other family was interested in participating in the study. Since the students from HOH, who were cognitively impaired, were not able to be interviewed, only their parents/caregivers were interviewed. As a result, 22 parents (13 from the JFK and 9 from the HOH) and 13 adolescents (all from the JFK) were asked to complete the face-to-face survey. The demographic data of the participants are listed in Table 1. Cerebral palsy and cognitive impairment were the principal types of DD. All adolescents received rehabilitation from the Hospital Authority and/or from their special school. All the adolescents accessed between four and seven paediatric medical specialists (eg paediatrician, neurologist, orthopaedic surgeon) and rehabilitation services (eg physiotherapy, occupational therapy, speech therapy) indicating their complex needs. Over 90% of the JFK students were followed up at the DKCH that is within walking distance of the school (personal communication, Senior Physiotherapist at JFK).

Table 2 summarises the participant responses about clinical transition. The majority of the parents (77%) and adolescents (85%) knew that clinical transition to adult care would occur at 18 years of age. They were mainly informed by their paediatrician (50% of parents and 69% of adolescents). Most parents (77%) were reluctant to make this move. Ten parents stated that their adolescent child was already receiving care from the adult sector and over half of them (60%) were dissatisfied with the service. Four of the 13 adolescents clearly stated that they had transitioned to the adult health service during the survey and all of them were happy with the transition. Among those 17 families who knew that clinical transition to adult care would occur at 18 years of age, 10 adolescents were all over 18 years old, whereas those in another seven (41%) families were also over 18 years old and still receiving services from the paediatric sector at the time of the study.

When asked why they were not willing to the transition or why they were dissatisfied after the transition, the parent responses could be summed up as two main areas of concern: reluctance to change and dissatisfaction with the adult health services. Most parents (16/22, 73%) did not want to change their existing care circumstances. When asked why, some parents cited dissatisfaction with the adult health service or health system (for the latter, 13/22, 59% of parents). For example, parents found it difficult to attend the follow-up appointments using public transport. Although there was a free shuttle bus service for families who needed it, parents were frustrated by the limited service.

Some parents also wanted more flexible visiting hours in the adult hospital so that they could look after their adolescent children, especially those who were cognitively impaired. The parents worried about the quality of care for their children who were entirely dependent for their daily activities. They were also unhappy about the waiting time for medical appointments and stated that their children with DD had a short attention span and were unable to control their behaviour. Long waiting times in a crowded waiting area, which is commonly observed in the adult setting, could easily trigger their behavioural problems.

There was also dissatisfaction with the adult health service providers (13/22, 59% of parents). Parents often found that the adult medical staff demonstrated limited understanding and knowledge of their child’s clinical presentation and abilities, especially for those with severe cognitive impairment. The adult health service providers did not know how to communicate with the cognitively impaired adolescents and treated them as other normal adults.

There is no formal clinical transition service in Hong Kong but when asked, the majority of parents (21/22, 95%) and adolescents (11/13, 85%) stated that they would welcome such a service. About two thirds of the study parents and adolescents (23/35, 66%) would like the clinical transition service to support them during the clinical transition. About one third of the parents (7/22, 32%) believed that the service could act as a bridge linking the paediatric and adult health services, providing information about available services in the adult sector.

The Figure summarises the responses of adolescents for self-perceived competency in managing their disability, and Table 3 summarises the study parents’ responses. Most adolescents demonstrated understanding of instructions (11/13, 85%), confidence in communicating with the service providers about their condition (10/13, 77%), and understanding the importance of treatments for their condition (12/13, 92%) [Fig]. About half were confident in seeking help from different specialties according to their condition (6/13, 46%) and making medical decisions (7/13, 54%) [Fig]. Over half of the adolescents, however, lacked the confidence to attend routine medical visits on their own (8/13, 62%) and worried about the unfamiliar adult medical service (6/13, 46%) [Fig]. Most parents stated that they were familiar with their children’s medical conditions and treatments (20/22, 91%) and able to seek help from different medical specialties based on their child’s condition (14/22, 64%) [Table 3]. Only a minority of parents (1/22, 5%), however, believed that their children were capable of attending medical appointments on their own. Less than half of the parents believed that their children would be able to explain their medical condition (9/22, 41%) or make independent clinical decisions in the future (7/22, 32%). None of the parents of an adolescent with cognitive impairment believed that the child would ever be able to manage their own health.

The present pilot study aimed to determine how adolescents with DD and their parents in Hong Kong accept the clinical transition and identify the main barriers to successful transition. This was the first step to understanding the issues of this population group during clinical transition and to enable planning for the future. As far as we know, this study is the first to be conducted in Hong Kong for this population group. Overall, 22 parents and 13 adolescents were recruited from two special schools (one for primarily physically disabled children and the other for severe physically and/or cognitively impaired individuals), aiming to understand what was the acceptance level and barriers faced by these two vastly different groups with DD. The results were very similar between these two subgroups, indicating that the study parents had similar issues during clinical transition, regardless of the type of DD of their child. Hence, the results from these two subgroups were discussed as one group.

Most of the study participants were aware of the clinical transition necessary at the age of 18 years. Only 10 (45%) of the 22 families shifted to the adult health service, despite the fact that their adolescent child was close to or over 18 years old (Tables 1 and 2). The reasons for this delay were not thoroughly explored but it has been suggested that medical practitioners in the paediatric service felt that the adolescents were not ready for the transition so they continued to see them well into adulthood while the parents and the adolescents were reluctant to make the move.11 The latter appeared to be true because when asked, most study participants did not want to change and move to the adult health service. This contradicts the results of a previous local study of adolescents with chronic medical conditions, in which over 80% of the study participants (adolescents and parents) were willing to move to the adult health service.11 The difference is likely due to the complexity of the health conditions of the present cohort. Adolescents with DD usually have varying degrees of physical and/or cognitive impairment and so depend more on others for managing their health condition, making them and their carers more anxious about any change.6 7 For those with chronic medical conditions, the physical and cognitive abilities of the adolescent were unlikely affected and hence the adolescents could manage their condition more independently and more readily after the transition.13 This speculation was supported by the findings about self-perceived competency level. Most study adolescents, who had mainly physical disabilities, were not confident about attending a medical appointment alone because of their limited physical abilities (Fig). The reluctance for change may also be due to fear of the unknown and of not being well prepared.11 In Hong Kong, clinical transition is non-structured and unplanned.11 Parents are often informed just before the transition, leading to poor preparation and confusion. Early and continuous clinical transition from early adolescence can enable parents and adolescents with DD to be prepared and actively participate in the transition planning.7 14 Although the clinical transition service is not well-known in Hong Kong, the study participants had a positive attitude towards a clinical transition service to help them navigate the process by bridging the paediatric and adult health services. In addition, the study parents wished to have more information about available adult health services, eg rehabilitation services, wheelchair maintenance services, etc. More information about the unknown has been shown to reduce the reluctance of parents and adolescents to change and to further improve their confidence about moving to adult care.5 6 15 16

Another barrier was dissatisfaction with the health care system and service providers in the adult setting (Table 2), and is in line with present literature.7 Some parents found it difficult to arrange transport to the adult hospital for follow-up while most of the appointments were currently at the special school. More accessible public transport might help, especially in Hong Kong, where private vehicles are not a common option. Flexible visiting hours in the adult hospital that would enable parents to care for their dependent adolescent child may also reduce their dissatisfaction. Longer waiting times for medical appointments in the adult setting was frequently mentioned by the study parents. In the adult sector, patients with all kinds of neurological conditions, both child-onset and adult-onset, are reviewed in the same clinic. The number of patients attending the clinic is vastly increased compared with the paediatric setting. In addition, patients with adult-onset neurological conditions and their family may not understand the characteristics of DD. Stressed behaviour of an adolescent child with DD may be perceived by other families as impatience. In the paediatric clinic, where all clinic attendees were children or adolescents with DD and their parents, the waiting time was shorter. Families as well as clinic staff had a full understanding of DD and would be more tolerant. It is likely that this lack of support in the adult setting further discouraged the study parents to make the transition willingly. Changes to the existing health care system, such as a separate clinic for child-onset DD conditions, may be a possible small step to assist this group in making a smooth transition. Education about clinical transition for staff in both the paediatric and adult settings allows them to prepare the families in advance. Education about paediatric conditions and communication with adolescents with DD can also equip adult staff with confidence so they develop a strong rapport with the families.16

Interestingly, from the perspective of the adolescents, the four adolescents who had transitioned stated that they were happy with the adult health service. Two (50%) adolescents indicated that because the ‘new’ doctors did not know them well, they paid more attention to them and one adolescent did not give any reason to support his statement. It is likely that in the paediatric sector, these adolescents had been followed up from early childhood by the same medical staff who virtually watched them grow up. A change of scene and people in the adult sector is welcomed by these adolescents. In addition, they might welcome the idea that they have started to actively participate in the consultation as a ‘patient’, unlike in the paediatric sector, where the consultation was directed at their parents, not them.14

Parents of adolescents who had physical and/or cognitive impairment had a similar perception of their adolescent child, that they would never be able to attend a medical appointment alone, presumably because of their disability (responses to questions 9 to 10 in Table 3). None of the parents of a cognitively impaired adolescent child believed their child to be capable of explaining their medical condition to others or making an independent medical decision. On the contrary, parents of a physically disabled child thought that while it may not apply at present, their child would be able to make their own decisions in future (responses to questions 11 to 14 in Table 3). Nonetheless, there was a discrepancy in this perception between the study adolescents and parents (Fig and Table 3). Most adolescents believed they could explain their condition to others (question 2 in the Fig) and over half believed that they could make an independent medical decision at the time of the study (question 7 in the Fig). Further studies are needed to determine whether this discrepancy is due to confusion on the part of the parents because of changing responsibilities during the transition.13 While western literature emphasises the importance of active participation by adolescents during clinical transition,14 it would be interesting to see if this can be endorsed in a parent-dominant Chinese society such as Hong Kong, where cultural differences may influence attitudes towards clinical transition.17

We were unable to analyse other challenges identified in overseas literature, such as unclear eligibility criteria and procedures and limited time for clinical transition, because comparable data were not available for Hong Kong. In other developed countries, adolescents are shifted with the assistance of a clinical transition service based in the children’s hospital (if any) or by applying clinical guidelines for best service.18 In Hong Kong, adolescents are referred from the paediatric section to the adult section within the same hospital. Each hospital cluster may have different procedures for this ‘transition’ and there is no defined department within the hospital structure to assist adolescents and their families through this process. Nor do the families receive any advice about how to negotiate this process. A future in-depth study is recommended to understand the existing situation of clinical transition in different hospital clusters and determine how to establish a more formal approach among all the hospital clusters in Hong Kong to support this group of adolescents and their families during this confusing time.

There may have been a selection bias in the study sample as the families were approached by convenience through the school staff. Due to the small sample size, no statistical analysis was conducted to compare the subgroups of adolescents with physical and cognitive impairments. Although the sample size was small, the purpose of the present pilot study was not to generalise the findings to all adolescents with DD but to begin to understand the acceptance of clinical transition and the main barriers to success for adolescents with DD and their family in Hong Kong. The present results are also in line with the literature in this area.4 7 11 14 17 Future studies with a larger sample size and more in-depth qualitative data are required to verify the present results. The potential subjective bias of the results, especially for the open-ended questions, was another limitation but we attempted to minimise this through consensus agreement among the team.

In the present explorative study, close to half of the study families had a delayed clinical transition to the adult health service. Most study parents were reluctant for their adolescent children to shift to the adult health service due to unwillingness to change and dissatisfaction with the adult medical service. A structured and well-planned clinical transition was urged by the study participants to bridge the paediatric and adult health services and to provide support to the family. Further studies are required to analyse the needs and concerns of adolescents with DD and their families as well as the service providers in the adult medical setting to facilitate the future development of a clinical transition service in Hong Kong.

The authors would like to thank all the participating families from the Hong Kong Red Cross John F Kennedy Centre and Haven of Hope Sunnyside School.

All authors have disclosed no conflicts of interest.

1. Westbom L, Bergstrand L, Wagner P, Nordmark E. Survival at 19 years of age in a total population of children and young people with cerebral palsy. Dev Med Child Neurol 2011;53:808-14. Crossref

2. Public Law 98-527, Developmental Disabilities Act of 1984.

3. Staff J, Mortimer JT. Diverse transitions from school to work. Work Occup 2003;30:361-9. Crossref

4. Blum RW, Garell D, Hodgman CH, et al. Transition from child-centered to adult health-care systems for adolescents with chronic conditions. A position paper of the Society for Adolescent Medicine. J Adolesc Health 1993;14:570-6. Crossref

5. American Academy of Pediatrics, American Academy of Family Physicians, American College of Physicians-American Society of Internal Medicine. A consensus statement on health care transitions for young adults with special health care needs. Pediatrics 2002;110(6 Pt 2):1304-6.

6. Bindels-de Heus KG, van Staa A, van Vliet I, Ewals FV, Hilberink SR. Transferring young people with profound intellectual and multiple disabilities from pediatric to adult medical care: parents’ experiences and recommendations. Intellect Dev Disabil 2013;51:176-89. Crossref

7. Stewart D, Stavness C, King G, Antle B, Law M. A critical appraisal of literature reviews about the transition to adulthood for youth with disabilities. Phys Occup Ther Pediatr 2006;26:5-24. Crossref

8. Persons with disabilities and chronic diseases in Hong Kong. Hong Kong: Hong Kong Census and Statistics Department; 2016. Available from: http://www.statistics.gov.hk/pub/B71501FB2015XXXXB0100.pdf. Accessed Jul 2016.

9. Clusters, hospitals & institutions. Hospital Authority. 2016. Available from: http://www.ha.org.hk/visitor/ha_visitor_index.asp?Content_ID=10036&Lang=ENG&Dimension=100&Parent_ID=10004. Accessed Jul 2016.

10. Hospital Authority Statistical Report 2012-2013. Hong Kong: Hospital Authority; 2013.

11. Wong LH, Chan FW, Wong FY, et al. Transition care for adolescents and families with chronic illnesses. J Adolesc Health 2010;47:540-6. Crossref

12. Hong Kong Society for Adolescent Health. Adolescent Transition Care Assessment Tool, Public Education Series No. 12 (2013). Available from: http://hksah.blogspot.hk/2013/11/adolescent-transition-care-assessment.html. Accessed 6 Feb 2016.

13. Stewart DA, Law MC, Rosenbaum P, Willms DG. A qualitative study of the transition to adulthood for youth with physical disabilities. Phys Occup Ther Pediatr 2002;21:3-21. Crossref

14. Viner RM. Transition of care from paediatric to adult services: one part of improved health services for adolescents. Arch Dis Child 2008;93:160-3. Crossref

15. Blum RW. Introduction. Improving transition for adolescents with special health care needs from pediatric to adult-centered health care. Pediatrics 2002;110(6 Pt 2):1301-3.

16. Stewart D. Transition to adult services for young people with disabilities: current evidence to guide future research. Dev Med Child Neurol 2009;51 Suppl 4:169-73. Crossref

17. Barnhart RC. Aging adult children with developmental disabilities and their families: challenges for occupational therapists and physical therapists. Phys Occup Ther Pediatr 2001;21:69-81. Crossref

18. Department of Health. National Service Framework for Children, Young People and Maternity Services. Transition: getting it right for young people. Improving the transition of young people with long term conditions from children’s to adult health services. 2006. Available from: http://dera.ioe.ac.uk/8742/1/DH_4132145%3FIdcService%3DGET_FILE%26dID%3D23915%26Rendition%3DWeb. Accessed Jul 2016.

Obese patients are particularly sensitive to the sedative and respiratory depressive effects of long-acting opioids. Many obese patients also have obstructive sleep apnoea syndrome (OSAS) and will be prone to airway obstruction and desaturation in the postoperative period, especially if opioids have been given.1 2 Given this background, multimodal analgesia is advocated for bariatric surgery with the aim of reducing opioid use.3 4 At the time of writing, no studies were able to demonstrate a technique that can consistently remove the need for any postoperative opioid analgesia. In this study, we report the use of an anaesthesia protocol that allowed a significant proportion of our patients undergoing laparoscopic sleeve gastrectomy to be completely free from any long-acting potent opioids in the intra-operative and postoperative period.

This was a prospective observational study. The study was conducted in a private hospital in Hong Kong that has been accredited as a Centre of Excellence for Bariatric Surgery. All patients scheduled for laparoscopic sleeve gastrectomy for management of obesity or type 2 diabetes from 1 January 2015 onwards were anaesthetised using the same protocol. We analysed 30 consecutive cases between 1 January 2015 and 31 March 2015 to investigate the postoperative opioid requirements using this anaesthesia protocol. Patients were excluded from the case series if they had contra-indications or allergy to any of the anaesthetic or analgesic drugs, or if anaesthesia deviated from the standard protocol for any reason. Three patients were excluded—one was taking serotonin-specific reuptake inhibitor antidepressants and pethidine was avoided to prevent serotonin syndrome (morphine given instead); one was allergic to non-steroidal anti-inflammatory drugs (NSAIDs), so intravenous parecoxib and oral etoricoxib were not given; one accidentally had a larger dose of ketamine given intra-operatively than allowed by the protocol. Concomitant laparoscopic cholecystectomy was performed with laparoscopic sleeve gastrectomy in three patients who were included in the study.

All patients were fasted from midnight on the night before surgery. All operations were scheduled in the morning. Patients were premedicated with oral pantoprazole 40 mg on the night before surgery, and 2 g of oral paracetamol and 150 mg or 300 mg of oral pregabalin (for patients of body mass index <35 kg/m² or ≥35 kg/m², respectively) 2 hours before surgery.

Upon arrival in the operating theatre, intravenous access was established and 1 to 2 mg of intravenous midazolam was administered followed by an infusion of dexmedetomidine. The dose of dexmedetomidine was titrated according to the calculated lean body weight (LBW) using the Hume formula.5 The starting dose of the dexmedetomidine was 0.2 µg/kg/h using LBW.6 No loading dose was given.

Standard monitoring was applied to the patient together with a bispectral index (BIS) monitor and peripheral nerve stimulation monitor. Graduated compression stockings and sequential compression devices were used for all patients. Induction of anaesthesia was accomplished with fentanyl 100 µg, a titrated dose of propofol, and either suxamethonium or rocuronium as appropriate. The trachea was intubated and patients were ventilated with a mixture of air, oxygen, and desflurane.

Intra-operatively, desflurane was titrated to maintain BIS value between 40 and 60. Muscle relaxation was maintained with a rocuronium infusion to keep a train-of-four count of 1. Dexmedetomidine infusion continued at 0.2 µg/kg/h or higher if necessary. Shortly after induction, the various supplementary analgesic drugs were given. A loading dose of ketamine 0.3 mg/kg LBW was given followed by intermittent boluses roughly equivalent to 0.2 to 0.3 mg/kg/h of LBW. Intravenous parecoxib 40 mg and tramadol 100 mg were given. Dexamethasone 8 mg and tropisetron 5 mg were given intravenously for prophylaxis of postoperative nausea and vomiting (PONV).

For intravenous fluids, patients were given 10 mL/kg actual body weight of either lactated Ringer’s solution or normal saline, then more were given as appropriate. Hypotension was treated with either ephedrine or phenylephrine.

When the surgeon started to close the wounds, rocuronium infusion was stopped and dexmedetomidine infusion rate was reduced to 0.1 µg/kg/h. Wounds were infiltrated with 20 mL of 0.5% levobupivacaine. When all wounds were closed, dexmedetomidine infusion was stopped and desflurane switched off, muscle relaxation reversed by neostigmine and atropine. Patients were extubated when awake and able to obey command.

After extubation, patients were transferred to the post-anaesthetic care unit (PACU) for observation for 30 minutes, or longer if appropriate. If a patient required rescue analgesia, intravenous pethidine 20 mg with intravenous ketamine 5 mg was given, and the dose repeated if necessary. When 10 mg of intravenous ketamine had been given, further rescue analgesia was intravenous pethidine 20 mg without any more ketamine. This avoided administration of too much ketamine in an awake patient causing dizziness or hallucinations. When patients had good pain control and stable vital signs, they were transferred back to the ward. The standard postoperative protocol was initiated: if patients requested analgesics, an intramuscular injection of pethidine 50 mg was given, and repeated after 4 hours if necessary. By early evening, when vital signs were stable, patients were allowed sips of water followed by a fluid diet of 60 mL/h. Regular oral paracetamol and etoricoxib were given, and oral pregabalin was added to the protocol the next day. Opioid requirements were reviewed for 24 hours after surgery.

As part of the standard postoperative protocol, patients were asked to get off the bed and walk around the ward with the assistance of nursing or physiotherapy staff by the evening of the day of surgery. Provided there were no complications, patients were discharged on the second postoperative day. The anaesthesia protocol is summarised in Table 1.

Patient characteristics are shown in Table 2, and postoperative opioid requirements are listed in Table 3.

Of the 30 patients, no opioid rescue analgesia was required in 14 (46.7%) throughout the postoperative period; six (20%) required intravenous pethidine for rescue analgesia in the PACU, but not after their return to the ward. The remaining 10 (33.3%) patients were given intramuscular pethidine injections in the ward on request.

The mean postoperative opioid requirement per patient in the whole case series was 32 mg of pethidine. Among the 16 patients who required rescue analgesia in the ward or in the PACU, their mean opioid requirement was 60 mg of pethidine, with a range of 20 to 150 mg.

This anaesthetic protocol included a dexmedetomidine infusion that might cause hypotension and bradycardia due to its alpha-2 adrenoceptor blocking action. In our case series, 11 (36.7%) patients developed transient hypotension despite intravenous fluid loading and required either intravenous ephedrine or phenylephrine. One patient had transient intra-operative bradycardia requiring atropine, probably due to preoperative use of a beta blocker and low resting heart rate.

Opioids are among the world’s oldest known drugs. They have been used in anaesthesia traditionally as part of a balanced anaesthesia, to provide hypnosis and analgesia, to blunt the sympathetic response to surgery, and are the mainstay of postoperative analgesia in many situations. Morbidly obese patients, however, are particularly sensitive to the respiratory depressant effects of opioids. Taylor et al2 found that the use of opioids per se is a risk factor for respiratory events in the first 24 hours after surgery. Ahmad et al1 demonstrated in their study of 40 morbidly obese patients who presented for laparoscopic bariatric surgery, that in using desflurane and remifentanil-morphine–based anaesthesia, hypoxaemic episodes in the first 24 hours were common, and 14 of their 40 patients had more than five hypoxic episodes per hour despite supplementary oxygen.

Another concern with use of opioids in bariatric patients is the high incidence (>70%) of OSAS.7 In our study, 30% (n=9) of patients had OSAS confirmed by an overnight sleep study. The remaining patients were not tested although many had varying symptoms of OSAS. These untested patients were assumed to have OSAS unless proven otherwise. The American Society of Anesthesiologists recommends that in patients with OSAS, methods should be used to reduce or eliminate the requirement for systemic opioids.8 Hence, reducing perioperative opioid use by these obese patients can potentially reduce morbidity.

How can the anaesthetist avoid or reduce the use of perioperative opioids, and yet still provide balanced anaesthesia with hypnosis, analgesia, haemodynamic stability, and satisfactory postoperative analgesia? The first method is to combine general anaesthesia with regional analgesia techniques, such that anaesthetic agents will provide hypnosis while the regional blocks will provide analgesia and block sympathetic responses to surgery. Any form of major regional block in a morbidly obese patient can be technically challenging, however. Furthermore, with respect to bariatric surgery, most procedures are now performed laparoscopically, so that thoracic epidural analgesia techniques have become largely unnecessary.

Putting aside the use of regional analgesia, the second method to reduce perioperative opioid use is to use a combination of non-opioid agents with volatile agents or propofol to achieve analgesia and haemodynamic control.3 A point to note here is that as acute tolerance to the analgesic effects of opioids can rapidly develop (such as after 90 minutes of remifentanil infusion),9 any attempts to reduce postoperative opioid requirement must include an effort to either eliminate or reduce the use of intra-operative opioids. These techniques are now often described as opioid-free anaesthesia or non-opioid techniques.

Paracetamol, NSAID, or COX-2 inhibitors, gabapentinoids, ketamine and alpha-2 agonists, when used individually, have all been shown to reduce postoperative opioid requirement and improve pain relief.10 11 12 13 14 Different combinations of these agents, together with local anaesthetic infiltration of the wounds, have been reported for bariatric surgery, as discussed below.

In 2003, Feld et al15 described a technique of using sevoflurane combined with ketorolac, clonidine, ketamine, lignocaine, and magnesium for patients undergoing open gastric bypass. Compared with the control group where sevoflurane was used with fentanyl, they found the non-opioid group to be less sedated, with less morphine use in PACU although the total morphine use at 16 hours was not significantly different to the opioid group.

In 2006 Feld et al16 again described using desflurane combined with dexmedetomidine infusion, and compared it with a control group using desflurane and fentanyl, for patients undergoing open gastric bypass. In the dexmedetomidine group, there were lower pain scores and less morphine use in the PACU.

In 2005, Hofer et al17 described a case report of a super-obese patient weighing 433 kg who underwent open gastric bypass. No opioids were used but instead replaced with a high-dose dexmedetomidine infusion together with isoflurane.

As laparoscopic techniques have become more common in bariatric surgery, more studies have been carried out of non-opioid anaesthetic techniques for laparoscopic bariatric surgery. Tufanogullari et al18 described a technique in which either fentanyl or varying doses of dexmedetomidine were used with desflurane for laparoscopic bariatric surgery. All patients were also given celecoxib. Postoperatively, patients were given fentanyl boluses in PACU, then intravenous morphine via a patient-controlled analgesia system. The only statistical difference was decreased PACU fentanyl use in the dexmedetomidine groups.

Ziemann-Gimmel et al19 looked at 181 patients undergoing laparoscopic gastric bypass. In the treatment group, volatile anaesthetics were used together with intravenous paracetamol and ketorolac. Postoperatively patients were given regular paracetamol and ketorolac. If there was breakthrough pain, intermittent oral oxycodone or intravenous hydromorphone was given. A small number of patients in this treatment group (3/89) were able to remain opioid-free throughout, and 15 patients did not require opioid medications when they were back to the ward.

In another study where the primary outcome was the incidence of PONV, Ziemann-Gimmel et al20 evaluated 119 patients undergoing laparoscopic bariatric surgery. The treatment group was managed with propofol infusion, dexmedetomidine infusion, paracetamol, ketorolac, and ketamine. The other group was managed with volatile anaesthetic and opioids. Postoperative analgesia regimen was the same as the previous study.19 They reported a large reduction in PONV in their treatment group.

While most studies reported decreased requirement of opioids for postoperative analgesia in their non-opioid groups, very few studies could achieve zero postoperative opioid use. Only Ziemann-Gimmel et al19 could achieve total opioid sparing in a small proportion (3 out of 92 patients) of the treatment group by using intra-operative and postoperative intravenous paracetamol and ketorolac.

Most of these earlier studies used a combination of only a few of the available non-opioid adjuncts. Dexmedetomidine remains a mainstay of non-opioid adjunct in most of these studies. We hence proposed the use of a wider mix of non-opioid adjuncts, using a combination of paracetamol, COX-2 inhibitor, pregabalin, ketamine, dexmedetomidine, and local anaesthesia infiltration. In contrast to the earlier studies, in our study we were able to achieve zero postoperative opioid use in a significant percentage of patients (46.7%).

In our protocol, the only opioid given during anaesthesia was fentanyl 100 µg for intubation, and tramadol 100 mg, a weak opioid, shortly after induction. All other opioid analgesics, if required, were given after the patient was awake. This avoided having to blindly give intra-operative long-acting opioids during anaesthesia, and allowed better titration of the drug by giving small boluses each time with the patient awake.

Dexmedetomidine was a useful agent in our protocol. Before the addition of this agent to our protocol, total opioid sparing was very difficult to achieve. Dexmedetomidine is a highly selective alpha-2 adrenoceptor blocker, with analgesic and sedative properties.21 Previous study of its use in bariatric anaesthesia has failed to show any reduction in opioid requirements.18 In our protocol, we used more non-opioid adjuncts, and since we calculated the infusion dose using LBW instead of total body weight (TBW), overall we administered a much lower dose of dexmedetomidine.

Infusion of dexmedetomidine may cause initial hypertension and tachycardia (especially during a loading dose infusion), followed by hypotension and bradycardia. In our study, no loading dose was given. Of the 30 patients, 11 (36.7%) developed transient hypotension despite intravenous fluid loading and required either intravenous ephedrine or phenylephrine. This transient hypotension was also aggravated by putting the patient in a steep reverse trendelenburg position to facilitate surgical exposure, which decreases the venous return. When using dexmedetomidine in bariatric surgery, care must be taken to ensure the patient is euvolaemic.

Ketamine was another useful adjunct in our protocol. Ketamine is an N-methyl-D-aspartate receptor antagonist with strong analgesic properties when given at subanaesthetic doses.22 The use of ketamine has advantages in morbidly obese patients as it causes little respiratory depression compared with opioids. In our protocol, we used LBW to calculate the ketamine dose, and used relatively low ketamine doses (0.3 mg/kg bolus followed by 0.2-0.3 mg/kg/h with intermittent boluses). This resulted in a low total ketamine dose, with a mean of 31 mg ketamine per patient (range, 25-50 mg). Midazolam 1 to 2 mg was also given at induction to prevent any psychomimetic reactions caused by ketamine. No patient developed any hallucinations or dysphoria and there was no delay in emergence noted in our patients.

In our protocol, we chose to use LBW to calculate the dose for dexmedetomidine and ketamine. The classic teaching is that for obese patients, anaesthetic drugs can be dosed according to the TBW versus ideal body weight or LBW according to lipid solubility. Lipophilic drugs are better dosed according to actual body weight due to an increase in volume of distribution, whereas hydrophilic drugs are better dosed according to LBW or ideal body weight.23 Lean body weight is significantly correlated with cardiac output, and drug clearance increases proportionately with LBW.6

There is insufficient information regarding the pharmacokinetics and pharmacodynamics of dexmedetomidine and ketamine in the morbidly obese patient. In the few previous studies regarding dexmedetomidine and bariatric anaesthesia, TBW was used as dosing scalars. For example, Feld et al16 used 0.5 µg/kg TBW loading dose followed by 0.4 µg/kg/h infusion in their series of 10 patients with open gastric bypass. Ziemann-Gimmel et al20 used 0.5 µg/kg TBW loading dose followed by 0.1 to 0.3 µg/kg/h infusion for their group of 60 patients undergoing a variety of bariatric procedures. Tufanogullari et al18 gave no loading dose and infused from 0 to 0.8 µg/kg/h in their series of 80 patients undergoing laparoscopic banding or bypass. There were little data regarding ketamine dose in bariatric surgery. We chose to dose these two drugs using LBW to see how our results would differ from the other published studies.

Our study has several limitations. It was a prospective observational study with a relatively small number of cases. We do not have data to compare this protocol with our previous protocols, nor do we have data in the form of a randomised controlled trial to look at the isolated effect of any of the drugs used.

The opioid that we used for rescue analgesia was pethidine, given intravenously in the recovery room by the anaesthetist, or given intramuscularly on the ward by the nurses upon standing order. One can argue that the mean opioid dose per patient was not accurate as some were given small intravenous boluses and others were given intramuscular injections of fixed dose. To accurately assess the postoperative parenteral opioid requirements in theory, all patients should be given a patient-controlled analgesia system to deliver boluses of parenteral opioids as required. This, however, is not practical and not necessary for the patient, given that two thirds of our patients did not require any opioids at all. This would also represent a lot of drug wastage when the whole cassette of drugs was unused.

We were able to demonstrate that a significant proportion of patients did not require any opioids, but we do not have data to demonstrate a reduction in respiratory complications or an improvement in time to ambulation or discharge. This could be the basis for further studies.

All authors have disclosed no conflicts of interest.

1. Ahmad S, Nagle A, McCarthy RJ, et al. Postoperative hypoxaemia in morbidly obese patients with and without obstructive sleep apnea undergoing laparoscopic bariatric surgery. Anesth Analg 2008;107:138-43. Crossref

2. Taylor S, Kirton OC, Staff I, Kozol RA. Postoperative day one: a high risk period for respiratory events. Am J Surg 2005;190:752-6. Crossref

3. Mulier JP. Perioperative opioids aggravate obstructive breathing in sleep apnea syndrome: mechanisms and alternative anaesthesia strategies. Curr Opin Anaesthesiol 2016;29:129-33. Crossref

4. Alvarez A, Singh PM, Sinha AC. Postoperative analgesia in morbid obesity. Obes Surg 2014;24:652-9. Crossref

5. Hume R. Prediction of lean body mass from height and weight. J Clin Pathol 1966;19:389-91. Crossref

6. Ingrande J, Lemmens HJ. Dose adjustment of anaesthetics in the morbidly obese. Br J Anaesth 2010;105 Suppl 1:i16-23. Crossref

7. Lopez PP, Stefan B, Schulman CI, Byers PM. Prevalence of sleep apnea in morbidly obese patients who presented for weight loss surgery evaluation: more evidence for routine screening for obstructive sleep apnea before weight loss surgery. Am Surg 2008;74:834-8.

8. American Society of Anesthesiologists Task Force on Perioperative Management of patients with obstructive sleep apnea. Practice guidelines for the perioperative management of patients with obstructive sleep apnea: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Management of patients with obstructive sleep apnea. Anesthesiology 2014;120:268-86. Crossref

9. Vinki HR, Kissin I. Rapid development of tolerance to analgesia during remifentanil infusion in humans. Anesth Analg 1998;86:1307-11. Crossref

10. Dahl JB, Nielsen RV, Wetterslev J, et al. Post-operative analgesic effects of paracetamol, NSAIDs, glucocorticoids, gabapentinoids and their combinations: a topical review. Acta Anaesthesiol Scand 2014;58:1165-81. Crossref

11. Blaudszun G, Lysakowski C, Elia N, Tramèr MR. Effect of perioperative systemic α2 agonists on postoperative morphine consumption and pain intensity: systematic review and meta-analysis of randomized controlled trials. Anesthesiology 2012;116:1312-22. Crossref

12. Cabrera Schulmeyer MC, de la Maza J, Ovalle C, Farias C, Vives I. Analgesic effects of a single preoperative dose of pregabalin after laparoscopic sleeve gastrectomy. Obes Surg 2010;20:1678-81. Crossref

13. Weinbroum AA. Non-opioid IV adjuvants in the perioperative period: pharmacological and clinical aspects of ketamine and gabapentinoids. Pharmocol Res 2012;65:411-29. Crossref

14. Alimian M, Imani F, Faiz SH, Pournajafian A, Navadegi SF, Safari S. Effect of oral pregabalin premedication on post-operative pain in laparoscopic gastric bypass surgery. Anesth Pain Med 2012;2:12-6. Crossref

15. Feld JM, Laurito CE, Beckerman M, Vincent J, Hoffman WE. Non-opioid analgesia improves pain relief and decreases sedation after gastric bypass surgery. Can J Anaesth 2003;50:336-41. Crossref

16. Feld JM, Hoffam WE, Stechert MM, Hoffman IW, Anada RC. Fentanyl or dexmedetomidine combined with desflurane for bariatric surgery. J Clin Anesth 2006;18:24-8. Crossref

17. Hofer RE, Sprung J, Sarr MG, Wedel DJ. Anesthesia for a patient with morbid obesity using dexmedetomidine without narcotics. Can J Anaesth 2005;52:176-80. Crossref

18. Tufanogullari B, White PF, Peixoto MP, et al. Dexmedetomidine infusion during laparoscopic bariatric surgery: the effect on recovery outcome variables. Anesth Analg 2008;106:1741-8. Crossref

19. Ziemann-Gimmel P, Hensel P, Koppman J, Marema R. Multimodal analgesia reduces narcotic requirements and antiemetic rescue medication in laparoscopic Roux-en-Y gastric bypass surgery. Surg Obes Relat Dis 2013;9:975-80. Crossref

20. Ziemann-Gimmel P, Goldfarb AA, Koppman J, Marema RT. Opioid-free total intravenous anaesthesia reduces postoperative nausea and vomiting in bariatric surgery beyond triple prophylaxis. Br J Anaesth 2014;112:906-11. Crossref

21. Carollo DS, Nossaman BD, Ramadhyani U. Dexmedetomidine: a review of clinical applications. Curr Opin Anaesthesiol 2008;21:457-61. Crossref

22. Gammon D, Bankhead B. Perioperative pain adjuncts. In: Johnson KB, editor. Clinical pharmacology for anesthesiology. McGraw-Hill Education; 2014: 157-78.

23. Sinha AC, Eckmann DM. Anesthesia for bariatric surgery. In: Miller RD, Eriksson LI, Fleisher LA, Wiener-Kronish JP, Young WL, editors. Miller’s anesthesia. 7th ed. Philadelphia: Churchill Livingston; 2015: 2089-104.

Ventriculoperitoneal (VP) shunting is one of the most common neurosurgical procedures performed to treat patients with hydrocephalus, which is a disorder related to an abnormal accumulation of cerebrospinal fluid (CSF) in the brain. The operation involves diverting CSF from the ventricles of the brain to the peritoneal cavity of the abdomen by catheter implantation. Despite being a well-established procedure, shunt failure can be as high as 70% in the first year with an annual occurrence rate of 5% thereafter.1 One of the main causes for failure is shunt infection, a potentially debilitating complication that more than doubles the risk of death and exposes affected patients to 3 times as many neurosurgical procedures as non-infected patients.2 Shunt infection varies and occurs in 3% to 17% of patients. Standard management involves intravenous antibiotic therapy, shunt removal, insertion of an external ventricular drain, and replacement with a new shunt once the patient’s CSF is free of microbial infection.1 3 4 5 6 The economic impact of VP shunt infection can be considerable. In the US, the median cost per episode per patient has been reported as US$23 500, accountable for US$2.0 billion in annual hospital charges.7 8 Evidence suggests that the adoption of a strict institutional implantation protocol can significantly reduce the risk of this most challenging shunt complications.9 10 11 12 This retrospective study aimed to determine the frequency of primary VP shunt reinsertions and infection among patients treated in Hong Kong’s public health system and to identify risk factors for shunt infection.

This was a multicentre retrospective study of patients who underwent VP shunt implantation at all seven Hong Kong Hospital Authority neurosurgical units. The Hospital Authority is a public service highly subsidised by the Hong Kong Special Administrative Region Government, and responsible for delivering health care for 90% of inpatient bed days in the city.13 Clinical research ethics committee approval was obtained from the participating centres. Patients who underwent primary VP shunting from 1 January 2009 to 31 December 2011 were included in this study. Those who underwent alternative CSF diversion procedures or those with a history of VP shunt implantation were excluded from this review. Data from clinical records, operation notes, medication-dispensing records, CSF biochemistry, cell counts, and microbiological cultures were collected. The primary endpoint for this study was primary VP shunt infection. The criteria for shunt infection were: (1) CSF or shunt hardware culture that yielded the pathogenic micro-organism with associated compatible symptoms and signs of central nervous system (CNS) infection or shunt malfunction5 14 15; or (2) surgical incision site infection, as defined by the National Nosocomial Infection Surveillance System, requiring shunt reinsertion (even in the absence of a positive culture)16; or (3) intraperitoneal pseudocyst formation (even in the absence of a positive culture). Secondary endpoints were shunt malfunction, defined as unsatisfactory CSF drainage that required shunt reinsertion, and 30-day mortality. Potential risk factors for shunt infection were classified as patient-, disease-, or surgical-related factors. All subjects were followed up for at least 30 days from the operation date or until death.

Statistical analysis was carried out using Pearson’s Chi squared test, Fisher’s exact test, and binary logistic regression to identify risk factors for shunt infection. The Kaplan-Meier (log-rank) and Cox proportional hazards models were employed for survival analysis. Patient, disease, and surgical factors were used as covariates and a stepwise regression strategy was adopted (Table 1). P values of <0.05 were considered statistically significant. All tests were performed using the Statistical Package for the Social Sciences (Windows version 16.0.1; SPSS Inc, Chicago [IL], US).

During the 3-year period, 538 patients underwent primary VP shunt implantation and 87% (n=470) had complete clinical follow-up with a median duration of 37 months (range, 3 days to 76 months). Seven (1%) patients were transferred to other hospitals within 30 days of the procedure. The median duration of hospitalisation was 42 days (range, 3 days to 36 months) and the median length of time from admission to shunting was 18 days (range, <1 day to 21 months). The clinical features and surgical variables are presented in Table 1. The mean (± standard deviation) age of patients was 48 ± 13 years (range, 13-88 years) and the male-to-female ratio was 1:1. In the study group, 80 (15%) were paediatric patients and 48 (9%) were infants. Overall, primary VP shunting was performed for post-aneurysmal subarachnoid haemorrhage communicating hydrocephalus in 169 (31%) patients, for CNS neoplasms in 164 (30%) patients, and for spontaneous intracerebral or intraventricular haemorrhage in 64 (12%) patients. For patients who had preoperative CSF sampling performed, the mean red blood cell count was 1900/µL, white cell count was 17/µL, total protein level was 0.78 g/L, and glucose level was 3.6 mmol/L.

Over one quarter of patients (n=155, 29%) had never had prior cranial neurosurgery and approaching half had undergone either one (n=141, 26%) or two (n=115, 21%) previous procedures. Antiseptic skin preparation was povidone-iodine 10% combined with another antiseptic in 422 (78%) patients and with povidone iodine alone in the remainder. The mean operating time for VP shunting was 75 ± 29 minutes. All patients had antibiotic prophylaxis of whom 328 (61%) were prescribed a third-generation cephalosporin and 40 (7%) had vancomycin. Twelve (2%) patients had a rifampicin-clindamycin antibiotic-impregnated ventricular catheter as part of the shunt system. The majority of operations were performed in an emergency setting (n=312, 58%) and shunt implantation was the sole procedure performed (n=514, 96%). The burr hole was most frequently positioned at the parietal location in 320 (59%) patients and 135 (25%) had a frontal burr hole. New burr holes were fashioned for shunt placement 95% of the time. The median number of surgeons was two, with a third of shunts performed by higher neurosurgical trainees (n=174, 32%) and the remaining performed by a neurosurgical specialist. Almost three quarters of VP shunts had a fixed-pressure valve (n=390, 72%) and the predominant design utilised was the Integra Pudenz flushing valve (Integra LifeSciences Corporation, Plainsboro [NJ], US) in 324 (60%) patients.

The rate of VP shunt reinsertion was 16% (n=87) and infection was 7% (n=36). The main causes for reinsertion were malfunction (9%) followed by infection. The annual proportion of shunts that required reoperation or were infected was comparable (P=0.87) [Fig 1]. The median time from shunt implantation to shunt removal for infection was 64 days (range, 2 days to 10 months). A cumulative risk for infection was noted affecting 3% of shunts in the first 30 days, 6% in 6 months, and 7% in 1 year. Although 68 (13%) patients were lost to follow-up, attrition analysis revealed that this did not affect infection rates. The mean follow-up duration in this subgroup between those with infection and those without was comparable at 526 days and 554 days, respectively (P=0.43). In addition, the incidence of shunt infection in patients with incomplete follow-up (5%) was similar to those with complete follow-up (7%) [P=0.42].

Most infections manifested as meningitis or ventriculitis (n=19, 53%), followed by wound breakdown (n=15, 42%) and peritonitis (n=2, 6%). The most common causative bacteria were coagulase-negative staphylococci (CoNS) [n=25, 69%] of which methicillin resistance was detected in 19 (76%) patients (Table 2). All CoNS species were sensitive to vancomycin with a quarter of methicillin-resistant (MR) species susceptible to aminoglycosides such as gentamicin or amikacin. The second most common infective agent affecting four (11%) patients was MR Staphylococcus aureus (MRSA). Polymicrobial infection was evident in six (17%) patients. One patient with peritonitis had mixed Gram-positive and -negative micro-organisms from CSF cultures.

The only patient risk factor for shunt infection was sex (Table 1). Male patients had a greater than two-fold increased odds of infection (odds ratio [OR]=2.2; 95% confidence interval [CI], 1.1-4.5). Traumatic brain injury (TBI) was the only disease risk factor (OR=7.8; 95% CI, 2.9-18.1). Surgical factors included the use of vancomycin as the prophylactic antibiotic (OR=3.7; 95% CI, 1.3-10.5) and shunts implanted as an emergency procedure (OR=2.2; 95% CI, 1.0-4.7). After adjusting for confounding factors, the independent risk factors for primary VP shunt infection were TBI (adjusted OR=6.2; 95% CI, 2.3-16.8), the use of vancomycin (adjusted OR=3.4; 95% CI, 1.1-11.0), and emergency shunting (adjusted OR=2.3; 95% CI, 1.0-5.1) [Table 3].

With respect to shunt infection, there was a difference in duration of shunt implantation for patients with the aforementioned risk factors as demonstrated by the significant separation of Kaplan-Meier survival curves (Fig 2). This was ascertained by Cox regression analysis (Table 3). Median shunt survival for trauma patients was 35 days (vs 154 days in non-trauma patients), 32 days for patients who received vancomycin (vs 124 days for alternative antibiotics), and 65 days for emergency operations (vs 208 days for elective operations).

In this study, 30-day all-cause mortality was 6% (n=32), but none was directly procedure-related. Almost half of these patients (n=15, 47%) had an underlying malignant CNS tumour; the majority being brain metastases (n=12, 80%). After accounting for patient age, sex, disease aetiology, shunt reinsertion and infection, a diagnosis of malignant brain tumour was the only significant independent predictor for 30-day mortality with an adjusted OR of 5.6 (95% CI, 2.6-11.7).

Ventriculoperitoneal CSF shunting has considerably reduced the morbidity and mortality of patients with hydrocephalus since its first description in 1908.17 More than a century later the operation remains the mainstay treatment for this condition. Despite the introduction of antibiotics, improvements in shunt materials and surgical techniques, VP shunt complications are common. Long-term epidemiological studies have indicated that more than half of all patients with CSF shunts will require a surgical revision in their lifetime.4 18 Shunt infection is a serious complication with potentially devastating consequences. Observational studies have recorded infection rates ranging between 3% and 17%, but more consistent estimates from larger patient cohorts cite rates of 6% to 8%.1 3 4 5 Our local shunt infection rate of 7% is relatively lower than other previously published findings and is in keeping with the results from other developed countries.

The wide range of shunt infection rates quoted in the literature is due in part to the diverse definitions adopted for shunt infection and the patient populations studied. Many studies have defined infection as a positive CSF microbial culture or the presence of CSF pleocytosis or low CSF glucose levels with clinical features of CNS infection.3 11 19 Due to the study design, a more pragmatic definition was adopted whereby infection was determined retrospectively by either a positive CSF or shunt hardware microbial culture in the presence of shunt malfunction.5 14 15 Nonetheless, it is acknowledged that the true incidence of shunt infection may be overestimated by false-positive cultures from skin flora. The reasons for selecting this interpretation for shunt infection were three-fold. First, it allowed for micro-organism identification and consequent epidemiological analysis; second, infection may not be clinically apparent with malfunctioning shunts; and third, CSF cultures alone cannot exclude infection in cases of shunt malfunction.15

The only disease risk factor independently associated with VP shunt infection was TBI. This may be due to two reasons. Delayed post-traumatic hydrocephalus invariably occurs in severe TBI patients and develops in over a third of those subject to decompressive craniectomies.20 Such patients often have a prolonged hospital stay and undergo multiple operations before a shunt is eventually implanted. In this cohort, TBI patients had a mean duration of hospitalisation of 89 days, which was 2 weeks more than the mean stay of 74 days for hydrocephalic patients with alternative neurosurgical conditions. Protracted hospitalisation may lead to skin colonisation with drug-resistant organisms that can evade single-agent conventional antibiotic prophylaxis.21 This is supported by evidence from this study where causative bacteria of shunt infection were resistant to the prescribed prophylactic antibiotic in 80% of TBI patients. These patients also had a mean number of three prior cranial procedures before shunting compared with two operations in patients with non-traumatic hydrocephalus aetiology. Previous surgery is well known to be a main cause of CSF leak in shunted patients and contributes to an increased risk of infection.5 22 Although in this patient series, the number of prior cranial procedures per se did not impart greater risk, detailed clinical data regarding CSF leak in TBI patients were not collected and therefore the influence of TBI on infection can only be inferred.

An unexpected finding was that patient age was not a risk factor for shunt infection. This is in contrast to several larger studies that identified paediatric patients, especially infants (younger than a year), to be particularly at risk.11 23 Infants have less-developed humoral and cellular immune systems with immature skin growth rendering them more vulnerable to shunt infection. A likely reason for this observation is the small number of paediatric patients (n=80, 15%) in this cohort with only 9% (n=48) being infants. Larger sample size may delineate more distinctive differences among age-groups.

There is little doubt that systemic antibiotic prophylaxis can prevent shunt infection.24 We, however, interestingly identified the sole use of vancomycin as a risk factor for shunt infection, a novel observation that has not been previously reported in the literature. The antibiotic was regularly reserved for patients allergic to penicillin-group antibiotics or for those with documented penicillin-resistant microbial infection or colonisation. This finding apparently seems counter-intuitive especially when all causative CoNS identified in this cohort were sensitive to vancomycin. The issue may lie with the timing of its administration before the procedure and its dosage. With regard to timing, systemic vancomycin requires slow intravenous infusion to reduce the risk of a hypersensitivity reaction that manifests as either red man syndrome or anaphylaxis and occurs in 3.7% to 47% of patients.25 To further illustrate the incidence of these symptoms, the first randomised controlled trial investigating its efficacy in shunt procedures was prematurely discontinued due to these adverse effects.26 Most hospital protocols require infusion rates over an hour as a minimum, but clinical trials have demonstrated that even lengthier 2-hour infusions can further reduce the frequency and severity of these reactions.25 27 Furthermore, the efficacy of vancomycin to treat CoNS and MRSA infections has been questioned due to observations of slower bactericidal activity, compared with nafcillin, than was previously recognised.28 To address this issue we suggest that rigid guidelines should be adhered to with respect to the adequate timing of vancomycin infusion before skin incision. Should more rapid infusions be required, for example, in the emergency setting, pre-administration of intravenous diphenhydramine before vancomycin infusion can prevent the development of red man syndrome.25

Limited data are available about the pharmacokinetics and CSF concentrations of vancomycin in neurosurgical patients. In a study reviewing intra-operative serum and CSF vancomycin concentrations of paediatric patients undergoing shunt implantation, the authors noted that CSF penetration was negligible in patients with non-inflamed meninges despite presumed adequate loading doses.29 This was echoed in a later study determining that among non-meningitic patients, vancomycin CNS penetration was poor with a CSF-to-serum ratio of only 18%.30 Its increasing use over the course of decades has also led to a corresponding rise in minimum bactericidal concentrations of CoNS.28 These unique findings should prompt an extensive review of prophylactic vancomycin use as there is currently no consensus on a recommended loading dose for neurosurgical procedures. In the meantime, researchers have attempted to improve the bactericidal activity in patients treated with vancomycin with varying measures of success. Vancomycin in combination with gentamicin results in more rapid bactericidal rates in animal models28 and has been proven to be as effective as third-generation cephalosporins in preventing surgical site infection for neurosurgical procedures in a randomised trial.31 Others have proposed intra-operative combined vancomycin-aminoglycoside administration either intraventricularly, for shunt hardware antibiotic bath immersion prior to implantation or applied in powder form within the subgaleal space of the wound with tenable positive results.11 32 33 34

Antibiotic-impregnated (by rifampicin with either clindamycin or minocycline) and silver-coated ventricular catheters offer the greatest promise in preventing shunt infection.35 36 There exists a growing body of evidence in support of antibiotic-impregnated ventricular catheters and they are gradually replacing conventional plain silicone catheters in daily practice with considerable cost savings.37 38 39 40 There are also accompanying concerns about the development of antibiotic-resistant micro-organisms and a recent meta-analysis has elucidated the higher risk of Gram-negative and MRSA shunt infections.38 In this series, only 12 patients received antibiotic-impregnated catheters during the study period so it is difficult to draw any conclusion about their effectiveness.

Emergency VP shunting is another surgical-related risk factor for infection and was performed in more than half of patients who underwent the procedure. Its significance is the greatest among the three independent factors identified and is possibly the most amenable to change in current practice. The clinical condition of most patients with hydrocephalus who require primary VP shunting does not warrant emergency surgery although a few indications exist, for example, obstructive pineal region or cerebellar tumours that may present with acute symptoms. More than two thirds of patients (70%) in this study had conditions that necessitated delayed shunting when the primary disease had been treated and the patients stabilised. It is most likely because of limited availability of operating theatre among other related resources and the general practice that VP shunting is delegated to more junior members of the surgical team that this phenomenon prevails. Several reasons support why ‘emergency’ primary shunting should be discouraged. It has long been established by several protocol-driven trials that shunting should be performed as the first procedure of the operative day to minimise the risk of contamination.9 10 11 To illustrate, a surgical incision time after 10 am was observed to be a predictor for infection.5 In elective procedures the neurosurgeon in-charge and other responsible operating theatre staff are likely to be more experienced in comparison with personnel involved in emergencies. In particular, it has been shown that individual surgical experience is an important factor for infection with researchers stating a higher incidence among neurosurgical trainees or in surgeons who performed fewer than 147 shunts within a decade.4 41 Nonetheless, using the former stratification of trainee versus specialist, this was not evident in our cohort. Another argument against ‘emergency’ VP shunting could be the location where the procedure is performed. For a variety of resource allocation reasons, shunting scheduled as an emergency procedure is often not performed in neurosurgery-designated operating theatres. A study investigating the distribution of bacteria in the operating room environment and its relationship with ventricular shunt infections concluded that positive environmental cultures were more likely to occur in a theatre not devoted to neurosurgery.42 Although procedure timing and location were not explored in this audit, it is believed that they were the principal explanations why shunts implanted as an emergency were more likely to become infected.

The time interval from shunt implantation to revision for infection in our study is longer than most published data with a median shunt survival of 64 days.5 34 Our data show that 92% (n=33) of shunt infections occurred within 6 months and is compatible with the commonly held belief that the infection begins intra-operatively with the inoculation of skin flora, either from the patient or surgeon, into the surgical wound.42 43 44 This is further substantiated by the predominance of CoNS and S aureus in 81% of bacterial cultures in this patient series and similarly in several previous reports.4 5 9 10 11 12 32 35 36 43 Coupled with positive research findings that theatre discipline during surgery reduces infection risk, it seems reasonable to conclude that institutional shunt implantation protocols should be established.9 10 11 12 32

Even though the performance of our neurosurgical community with regard to primary VP shunt infection meets international standards, there is room for improvement. The implementation of a standardised shunt surgery protocol that covers preoperative preparation as well as intra-operative and postoperative management has consistently been proven to be effective in reducing infection.9 10 11 12 32 The landmark study by Choux at al10 first demonstrated that meticulous measures—such as adopting a no-touch technique for shunt handling, limiting the length of shunt exposure time and the number of people in the operating room—have dramatically decreased shunt infection rates from 16% to less than 1%. It is our belief that a similarly comprehensive protocol should be developed and based on the findings of this preliminary study.

This study has several limitations. Data collection was retrospective so key clinical information such as the presence of CSF leak and patient co-morbidities were missing. This may have led to inadequate control for confounding factors. An additional limitation inherent in studies of this nature is the potential presence of observational bias where data were collected without blinding after outcomes were known. Follow-up was incomplete with 68 (13%) patients defaulting from clinical review over the course of 3 years. Inadequate follow-up duration was also noted; seven (1%) patients were transferred to other hospitals within 30 days of the procedure and this might have influenced 30-day all-cause mortality findings. Finally, our definition of shunt infection did not include abnormal CSF biochemistry criteria that could have confirmed or refuted positive culture results of specimens that might have been contaminated during collection.

This is the first territory-wide review of infection in primary VP shunts conducted in Hong Kong’s public health care setting. This study is also one of the largest in the literature examining shunt infection complications among a predominantly Chinese population. Shunt infection was the second most common cause for reinsertion occurring in 7% of patients. Significant independent predictors for shunt infection were TBI, vancomycin administration for prophylaxis, and procedures performed in an emergency setting. Although VP shunt infection rates meet international standards, there are areas of improvement that can be readily addressed such as the timing or dosage of vancomycin and the avoidance of performing the procedure as an emergency. The best approach to reducing shunt infection may be the design and adoption of a standardised shunt surgery protocol customised to local practice.

We would like to thank members of the Hospital Authority Head Office (HAHO) Co-ordinating Committee (Neurosurgery), the Clinical Effectiveness & Technology Management Department, the Division of Quality and Safety, and the Clinical Data Analysis and Reporting System Team, HAHO IT Service for their administrative advice and data collection. We also wish to thank Drs Chris YW Liu, Alphon HY Ip, and Claudia Law for their contributions in data collection and entry. This study was supported by the Tung Wah Group of Hospitals Neuroscience Research Fund.

All authors have disclosed no conflicts of interest.

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