We investigated the average operating time and extent of intra-operative blood loss in orthognathic surgeries performed using induced hypotensive general anaesthesia, with the intention of devising a practical guideline for blood unit preparation for these procedures. We prospectively studied 32 Chinese patients undergoing surgery to correct dentofacial deformities at a public hospital in Hong Kong from 1 December 1997 to 1 December 1998. Most patients (72.4%) needed double-jaw surgery. The mean estimated blood loss was approximately 617.6 mL. The blood loss during simple Le Fort I osteotomies was about half that of multiple segmentalised osteotomies. For mandibular ramus osteotomies, the mean blood loss and operating time for were approximately 280 mL and 2 hours, respectively; for anterior mandibular osteotomies, the corresponding values were 171.3 mL and 1 hour 13 minutes. The average drop in the haematocrit value was 15.4%, and the crossmatch to transfusion ratio was 29. A bivariate correlation test between the blood loss and operating time gave a strong correlation (P<0.01), as did blood loss with a drop in haematocrit value (P<0.01). Orthognathic surgeries are thus safe and predictable in terms of intra-operative blood loss and operating time, and a 'type, screen, and save' policy for blood unit preparation is more appropriate than a 'crossmatch' policy.

Obstructive sleep apnoea syndrome is a common but underrecognised disorder with associated substantial morbidity and mortality. Excessive daytime sleepiness caused by the disorder leads to poor work performance and increases the risk of an individual having an automobile accident. The main objective of treatment for sleep apnoea is the relief of disabling daytime sleepiness and the improvement of quality of life. Conservative measures such as weight reduction and the avoidance of alcohol should be initiated when appropriate. Nasal continuous positive airway pressure devices have remained the standard treatment since it was first introduced in 1981. Oral appliances provide an alternative treatment choice in mild-to-moderate cases, whereas surgery is useful in selected cases.

Prospective randomised controlled trials performed in North America and Europe have demonstrated that the risk of future stroke or death is substantially reduced by performing carotid endarterectomy in symptomatic patients who have severe carotid stenosis. An audit was conducted to analyse the results of carotid endarterectomy performed during a 3-year period, at a tertiary referral vascular centre in Hong Kong. A total of 35 patients who had significant carotid stenosis underwent 36 carotid endarterectomies from October 1994 to September 1997. All patients recovered uneventfully without neurological complications or mortality. The audit showed that the current results of carotid endarterectomy at this institution fulfilled the criteria advised by the Stroke Council of the American Heart Association in 1995. Therefore, carotid endarterectomy is a validated therapeutic option for carotid stenosis in Hong Kong.

Leukocyte contamination during blood transfusion can cause many adverse effects, such as the transmission of cell-associated infectious agents, febrile non-haemolytic reactions, graft-versus-host disease, and immunosuppression. While using leukodepleted blood components can minimise some of these adverse effects, the leukodepletion of all cellular blood components is costly. A more cost-effective alternative would be to supply leukodepleted blood components to at-risk patients only.