Intrathecal hyperbaric bupivacaine dose response in postpartum tubal ligation patients

Because of its short duration, hyperbaric lidocaine has been a popular intrathecal drug to provide anesthesia for postpartum tubal ligation (PPTL). However, reports of transient symptoms associated with its use have prompted the search for alternative intrathecal local anesthetics for short procedures. Hyperbaric bupivacaine is rarely associated with transient neurologic symptoms, and we designed this study to determine the optimal dose of bupivacaine for PPTL that assures adequate sensory block and allows the patient the shortest recovery time.

Forty American Society of Anesthesiologists (ASA) I-II patients undergoing spinal anesthesia for PPTL were randomly assigned to receive 5.0, 7.5, 10.0, or 12.5 mg hyperbaric bupivacaine in the right lateral position.

Despite sensory block above T-8 in all groups, 4 of the 5 patients in the 5-mg group developed blocks insufficiently dense for surgery and required general anesthesia. Failed spinals occurred evenly in the remaining groups. Motor regression was significantly more rapid with decreasing doses of bupivacaine. Time in the postanesthesia care unit (PACU) was shorter in the 7.5-mg group.

Hyperbaric bupivacaine 7.5 mg injected in the lateral position provides adequate surgical anesthesia for PPTL with a minimal duration of motor block and recovery time.