“Low Dose” of bupivacaine vs conventional dose during spinal anesthesia for cesarean section. ¿Do they have the same analgesic effectiveness?

Abstract

Introduction. Spinal anesthesia is the most widely used technique for cesarean section; the use of high doses of local anesthetic is associated with hypotension which affects maternal and fetal welfare. Numerous studies have associated opioids to reduce the dose of local anesthetic seeking greater hemodynamic stability, however, the efficacy of analgesia with low dose is still controversial. Objectives. To compare the efficacy of analgesia in two different patterns of hyperbaric bupivacaine of spinal way for cesarean section. Materials and methods. A prospective, randomized, double blind in 65 pregnant patients undergoing cesarean section with two different regimens of hyperbaric bupivacaine with fentanyl spinal. Group 1: 7.5 mg + 25 mcgr fentanyl and group 2: 12.5 mg + 25 mcgr of fentanyl. Results. The occurrence of side effects was similar between groups, but hypotension during cesarean section occurred in 21 patients (64%) in group 2 (p = 0,001). The relative risk of pain at any time during anesthesia-and surgery-to administer low doses of hyperbaric bupivacaine compared to standard dose is 1.91 (95% CI 1.26-2.9). Conclusions. Spinal anesthesia with low doses of hyperbaric bupivacaine combined with intrathecal fentanyl for spinal anesthesia in cesarean section provides intraoperative hemodynamic conditions acceptable but is associated with the presence of intra-and postoperative pain, intraoperative changing conditions and becoming a factor of dissatisfaction both the patient and the obstetrician. The use of low-dose technique should be practiced by combined spinal-epidural anesthetic.