Protocol for Epidural Extension Anesthesia
pain
A blinded investigator (N.S. or M.W.) confirmed that participants had at least a bilateral T10 sensory level preoperatively. Alternative neuraxial anesthesia was offered if the block had not reached a T10 level. Participants were then transferred to the operating room, and routine monitoring was reapplied. The sensory and motor block were assessed according to the Modified Bromage score.Epidural extension anesthesia was standardized on the basis of institutional practice. A co-load of lactate ringers solution (500 mL) was given intravenously over approximately 15 minutes. After confirming negative aspiration of the epidural catheter, a test dose of 5 mL of 3% chloroprocaine was given, and the patient was monitored for signs of accidental intrathecal injection. If no abnormal signs were observed after 3 minutes, a further 15 mL of 3% chloroprocaine was injected over approximately 1 minute. The start of this injectate was defined as time zero and the beginning of epidural extension. A blinded investigator (N.S. or M.W.) assessed the block at 1-minute intervals, initially moving from a caudal to a cranial direction and then more frequently as the block ascended. A Neurotip (Owen Mumford) provided a standardized sharp-pain stimulus.If a T6 bilateral block was not achieved within 10 minutes after the start of epidural extension, then 5-mL aliquots of epidural 3% chloroprocaine were administered every 5 minutes up to a total maximum cumulative dose of 30 mL. If the block did not reach a T6 level within 20 minutes, the attending anesthesiologist provided a different anesthetic technique according to clinical discretion. A phenylephrine infusion was started at 25 µg per minute, and the dose was titrated to maintain systolic blood pressure within 15% of preoperative baseline.Intraoperatively all patients received intravenous cefazolin (2 g), dexamethasone (4 mg), ondansetron (4 mg), and ketorolac (30 mg) in the absence of contraindications. After delivery of the infant, an intravenous oxytocin infusion was commenced, and 3 mg of epidural morphine was administered for postoperative analgesia, followed by oral acetaminophen (650 mg every 6 hours), ibuprofen (600 mg every 6 hours), and oxycodone (5-10 mg every 4 hours) for breakthrough pain as required.