EDITOR—The prevention of deep vein thrombosis and pulmonary embolism is a major consideration in all surgical patients. Unfortunately, the anaesthetic implications of thromboprophylaxis are rarely discussed, and this was once again the case in the article by Gorman et al.1

The authors recommend low dose unfractionated heparin for the prevention of deep vein thrombosis in general surgical patients. The regimen described causes little risk of serious surgical bleeding. However, spinal or epidural anaesthesia performed in a patient who had received this treatment would be potentially dangerous, as this is the time of high or peak anticoagulant activity. This increases the risk of vertebral canal haematoma, which can lead to permanent paraplegia. The risk can …