Abstract #: 25 Spinal anesthesia for cesarean delivery: Study of equivalence using bupivacaine withor without fentanyl

: 25 Spinal anesthesia for cesarean delivery: Study of equivalence using bupivacaine with or without fentanyl Presenting Author: Rachel A Meyer BSc, MD Presenting Author's Institution: University of Toronto Toronto, Ontario Co-Authors: Alison J Macarthur BMSc, MSc, MD Mount Sinai Hospital Toronto, Ontario Kristi Downey MSc Mount Sinai Hospital Toronto, Ontario Abstract Body: Spinal anesthesia is the most popular form of anesthetic used for elective cesarean deliveries. The addition of fentanyl to spinal anesthetics allows for a lower dose of local anesthetic and reduces the incidence of maternal hypotension. Intrathecal fentanyl, however, has several disadvantages including increased risk of nausea, vomiting and pruritus. The evaluation of whether fentanyl is necessary has not been completely studied. This study tested the hypothesis that 15mg of intrathecal hyperbaric bupivacaine would produce equivalent spinal anesthesia for cesarean delivery as the combination of 12mg of bupivacaine with 15μg of fentanyl. This was a single center, double-blind, randomized clinical trial of equivalence. Consent was obtained from non-laboring, healthy parturients scheduled for elective cesarean delivery. Patients were randomized to receive either 15mg of intrathecal hyperbaric bupivacaine (Group B) or 12mg of bupivacaine with 15μg of fentanyl (Group BF). Both groups’ injectate also included 150μg of morphine. The primary outcome was the subject’s description of degree of sensation at 20 minutes after spinal injection. This description was classified into 1 of 4 categories: 1=complete absence of sensation; 2=sensation of motion only; 3=mild discomfort but the patient declined offer for additional analgesia; 4=the patient expressed a wish or exhibited an obvious need for additional analgesia. Secondary outcomes included spinal block characteristics, side effects, maternal hemodynamics, need for supplemental analgesia and patient satisfaction. One hundred thirty-eight women, enrolled between January and August 2009, were analyzed. There was no difference in the quality of anesthesia between the groups as assessed by degree of sensation at 20 minutes. Sixty-eight of 69 and 69/69 patients in Group B and Group BF respectively had anesthesia classified as successful (categories 1-3). The majority of patients in each group had “sensation of motion only” (category 2). The only two secondary outcomes that were different between the groups were change in MAP and incidence of nausea (Table 1). The important finding of this study is that 15mg of intrathecal hyperbaric bupivacaine alone produced spinal anesthesia for cesarean delivery equivalent to 12mg of intrathecal hyperbaric bupivacaine in combination with 15μg of intrathecal fentanyl. The larger decrease in MAP seen in Group B was likely due to inadequate vasopressor therapy. Additional File: