[A case of gastrectomy under continuous subdural anesthesia]

Unintentional subdural block, while attempting epidural block, is known as a complication. The authors used a catheter which had happened to be introduced into the subdural space, for clinical anesthesia and postoperative pain relief. For a 75-year-old male patient, gastrectomy was scheduled under epidural anesthesia. Epidural puncture was at the T 7 and T 8 interspace using loss of resistance method with saline under fluoroscopic guidance. We examined the catheter position by injecting iopamidol and confirmed subdural catheterization by subsequent computed tomography. After obtaining informed consent and agreement from the patient, "subdural anesthesia" was conducted. Ten ml of 0.5% bupivacaine was injected with 20 mg ephedrine as an initial dose. Twenty min after the injection, pin pricking revealed that analgesia had extended from the C 5 to S 1 dermatoms. Consciousness was clear and blood pressure was stable. Then, surgery was started. Since blood pressure tended to fall down gradually, we injected 40 mg of ephedrine subcutaneously 45 min after the subdural injection. At a 2 hours interval from the initial subdural injection, 5 ml of 0.5% bupivacaine was additionally injected. Respiration was stable throughout the surgery and the surgery was finished uneventfully. Analgesic level was from C 5 through S 3 at the end of surgery. Bupivacaine 0.25% was continuously infused at a rate of 2 ml.h-1 for 7 days for postoperative pain relief. The patient never complained of pain during the period. This report demonstrates that subdural block has a potential capability as an anesthesia for laparotomy as far as it is managed properly.