Anaesthesia
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Recent studies have demonstrated significant variation in bilateral jugular venous oxygen saturation measurements which may be of clinical significance. We have therefore measured variations in normal dural sinus venous drainage to assess the possible effects of normal anatomical variations on measured jugular venous oxygen saturation. Normal volunteers (n = 25) were imaged using magnetic resonance venography to demonstrate variations in venous anatomy. ⋯ The effect of the observed asymmetry on jugular venous oxygen saturation was modelled based on the assumption of either a supratentorial or infratentorial lesion. This model predicted significant asymmetry in jugular venous oxygen saturation measurements (> 10%) in 65% of cases with a supratentorial lesion which is in close agreement with clinical observations. This study suggests that normal variations in venous drainage may account for observed asymmetry in jugular venous oxygen saturation measurements.
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Case Reports
Epidural haematoma following anticoagulant treatment in a patient with an indwelling epidural catheter.
We report the occurrence of an epidural haematoma after the removal of a lumbar epidural catheter, which had been inserted 2 days previously for surgery to revise a thrombosed femoral-popliteal graft. Pre-operatively the patient received intravenous heparin by infusion, but this was stopped 7 h prior to epidural insertion. Coagulation studies were normal. ⋯ The epidural catheter was inadvertently removed while the patient was anticoagulated and paraparesis developed overnight. After a significant delay, an epidural haematoma was diagnosed and treated by decompressive laminectomy. At operation an epidural haematoma extending posteriorly from T12 to L3 was removed.