[Subdural spread of a local anesthetic following installation of a peridural catheter].

We report 4 cases of inadvertent subdural injection of local anesthetics among 640 patients receiving epidural anesthesia. In contrast to subarachnoid injection a typical sign was the development of patchy anesthesia in cervical segments and with late onset of symptoms. The case of a 63 year old woman scheduled for aortofemoral bypass surgery in epidural anesthesia is reported. She developed paresthesia, paresis and signs of sympatholysis in both arms 30 min after the injection of 10 ml bupivacaine 0.5% at T10-11. These symptoms lasted for 7 h. Subdural injection was documented using radiopaque dye. Two other cases of probable subdural injection leading to paresthesia and paresis in cervical segments after lumbar injection of 50 or 75 mg bupivacaine are reported. The symptoms began 15-30 min after injection and lasted for 60 min. The fourth case was that of a 26-year-old woman scheduled for cesarean section under epidural anesthesia. Following the injection of 75 mg bupivacaine 0.5% patchy anesthesia extending to T10 developed. By 10 min after an additional injection of 25 mg bupivacaine 0.5% she had paresis and paresthesia in both arms and was unable to cough. Her trachea was therefore intubated; 30 min later the level of anesthesia was below T5 and she could be extubated. Uneventful cesarean section was then performed. These cases demonstrate that as well as subarachnoid injection, inadvertent subdural injection of local anesthetic agents is a potential hazard of epidural anesthesia, not only in patients in an advanced state of pregnancy but also in nonpregnant patients.(ABSTRACT TRUNCATED AT 250 WORDS)