Accidental subdural block after epidural anesthesia in obstetric patient: Case report

Background: Although often overlooked, subdural anesthesia is a relatively common complication. It can present with a wide range of symptoms, from unexpectedly high sensory and limited motor blocks to significant hemodynamic and respiratory effects. Case Presentation: This case report documents the labor and delivery of a 26-year-old primigravida at 40 weeks gestation who requested an epidural at 4 cm. A 500 ml lactated Ringer's solution bolus was initiated prior to the procedure and a Tuohy needle, size 18-gauge, was utilized to locate the epidural space. Following a negative aspiration and falling meniscus test, a bolus of 8 ml containing a combination of 0.2% ropivacaine with 2 mcg/ml fentanyl was administered, resulting in a brief drop in blood pressure, which responded to ephedrine. An epidural infusion of 0.2% ropivacaine with 2 mcg/ml fentanyl was then started and continued until the decision was made to perform a caesarean section due to lack of progress. Prior to surgery, the epidural was supplemented with 15 ml of 0.75% ropivacaine and 50 mcg of fentanyl. Following the successful delivery of a healthy baby, the patient reported difficulty breathing, and her oxygen saturation dropped to 90%. She was intubated without medication and later extubated after the completion of surgery. The epidural provided pain relief for six hours postoperatively and the patient recovered fully without any neurological deficits. Conclusion: The case report describes an epidural anesthesia that resulted in respiratory depression and unconsciousness without sympatholysis. The local anesthetic diffused into the dura- arachnoid interface, or the subdural space, which facilitated the movement of the anesthetic cephalad. However, the patient experienced complete neurological recovery. This case demonstrates the importance of careful monitoring and prompt intervention in the event of complications during epidural anesthesia. Keywords: subdural anesthesia, primigravida, ropivacaine, unconsciousness.