Fentanyl as an adjunct to bupivacaine in spinal anesthesia to reduce intraoperative nausea during uterine exteriorization and internalization in elective cesarean section
Abstract Number: T 13
Abstract Type: Original Research
Nausea and vomiting are primarily regulated by the chemoreceptor trigger zone and vomiting center in the brain. Physiologic changes during pregnancy such as impaired GI motility, incompetent LES, and stomach compression by a gravid uterus, are some of the causes that can predispose these patients to develop nausea and vomiting. Overall, there are many causes of intraoperative nausea and vomiting during cesarean section under regional anesthesia such as: hypotension, increased vagal activity, neuroaxial opioids, surgical stimuli, uterotonic agents, and motion. It is known fact that uterine exteriorization and internalization of the uterus can cause visceral stimulation, mediated by unmyelinated C-fibers, and induce emesis. Our study aim is to evaluate intraoperative nausea during uterine exteriorization and internalization of the uterus with the addition of 0.4cc (20mcg) of fentanyl or the addition of 0.4cc of preservative-free normal saline to 1.2cc (9mg) to 0.75% bupivacaine in spinal anesthesia, in obstetric patients during the elective cesarean delivery. We also assessed the overall nausea and hemodynamic stability. Sixty-eight patients who underwent elective cesarean section were randomly assigned into these two groups. The degree of nausea was recorded at five minute intervals using the Overall Nausea Scale as well as their vital signs. Results have demonstrated an increased prevalence of nausea during uterine exteriorization and internalization in the saline group (21%) compared to the fentanyl group (8.6%). No significant difference has been observed in recorded vital signs between these groups. Intrathecal fentanyl decreased the incidence of nausea during uterine exteriorization and internalization in a cesarean section. Intrathecal fentanyl enhances analgesia and sensory block and could blunt the visceral stimulation through C-fibers. The decrease of visceral pain may also lead to less nausea during exteriorization and internalization of the uterus.