adequate anesthesia and more effective analgesia by adjusted doses of bupivacaine during cesarean section: a randomized double-blind clinical trial

Background: several adjuvants, added to local anesthetics, were suggested to induce an ideal regional block with high-quality analgesia. the purpose of this study was to evaluate the particular blocking properties of low-dose bupivacaine in combination with meperidine and fentanyl in spinal anesthesia during cesarean sections.methods: a randomized, double-blind clinical trial was conducted at hafez hospital affiliated with shiraz university of medical sciences (shiraz, iran) from february 2015 to february 2016. a total of 120 pregnant women, who underwent spinal anesthesia during elective cesarean section were enrolled in the study. based on block-wise randomization, the patients were randomly assigned to three groups, namely “b” group received 2 ml bupivacaine 0.5% (10 mg), “bm” group received 8 mg bupivacaine and 10 mg meperidine, and “bf” group received 8 mg bupivacaine and 15 µg fentanyl intrathecally. the block onset, the duration of analgesia, and the time of discharge from the post-anesthesia care unit (pacu) were all assessed. data were analyzed using spss software version 21, and p<0.05 were considered statistically significant.results: the mean duration of motor blocks in the b group (150 min) were significantly higher than the bm (102 min) and bf (105 min) groups (p<0.0001). in both the bm and bf groups, the duration of sensory and motor blocks was the same. the length of stay in the pacu was significantly longer in the b group (p<0.001) than the bm and bf groups. when meperidine or fentanyl was added to bupivacaine, the duration of the analgesia lengthened (p<0.001). conclusion: intrathecal low-dose spinal anesthesia induced by bupivacaine (8 mg) in combination with meperidine and/or fentanyl for cesarean section increased maternal hemodynamic stability, while ensuring effective anesthetic conditions, extending effective analgesia, and reducing the length of stay in pacu.trial registration number: irct2015013119470n14.