Prophylactic ondansetron for prevention of maternal hypotension following spinal anesthesia in women undergoing cesarean section

Abstract

Background: Spinal anesthesia induced hypotension is a common problem that occurs in the parturient undergoing elective cesarean section. Prevention of maternal hypotension (MH) could improve safety of spinal anesthesia and satisfaction for both the patient and anesthesia provider. Many techniques have been researched and utilized to reduce the occurrence of hypotension; nevertheless, no single intervention has surfaced to be entirely successful. Ondansetron, a 5-hydroxytryptamine-3 (5-HT3 or serotonin) receptor antagonist, is a commonly used antiemetic medication in obstetric anesthesia for prevention or treatment of nausea and vomiting but its use for prevention of hypotension is still in question. Objective: The objective of this systematic review was to synthesize the best available evidence on the clinical effectiveness of prophylactic ondansetron on diminishing hypotension following spinal anesthesia. Methods: Types of participants Patients irrespective of ethnicity and age undergoing spinal anesthesia for elective cesarean section who received intravenous prophylactic ondansetron or placebo prior to subarachnoid cannulation and anesthetic administration. Types of intervention(s)/phenomena of interest The review included studies that explored the use of ondansetron to a control group and reported frequency of hypotension. Types of outcomes The review considered studies that reported the incidence of hypotension as defined by the researchers and met the hypotension definition detailed in this review: decrease in systolic, diastolic or mean arterial blood pressure more than 20% compared to baseline, or a systolic measurement less than 90 mmHg or diastolic less than 60 mmHg. Search strategy A comprehensive search strategy was utilized to find both published and unpublished studies in the English language, due to resource constraints, from January 1980 through July 2015. A search of PubMed, EMBASE, Cochrane Central Trials Register, Web of Science, Wiley online Library, TRIP, [email protected], and ScienceDirect was carried out. New York Academy of Medicine Grey Literature Report, AHRQ, and ProQuest Dissertations and Theses were utilized for unpublished research. Methodological quality Two independent reviewers utilized the Joanna Briggs Institute Critical Appraisal Checklist for Randomized Controlled Trials. Data extraction Incidence of hypotension for both the ondansetron and placebo groups was extracted from the studies using the Joanna Briggs Institute Data Extraction Form from JBI-MAStARI. Data Synthesis DerSimonian and Laird random and fixed effects model using the CMA software was applied to the extracted quantitative data after it was pooled for meta-analysis. Standard chi-square test was used to assess for heterogeneity. Results: Two common doses (4 mg and 8 mg) of ondansetron surfaced from the nine included studies in this systemic review. Pooling of data from 7 RCTs indicated a statistically significant decrease in hypotension, p = 0.002 and relative risk (RR) of 0.494, (95% CI 0.314 to 0.779) in the parturient that received 4 mg of ondansetron. Data pooled from 4 RCTs indicated no statistically significant decrease in hypotension when 8 mg of ondansetron was administered, p = 0.753 and RR of 0.964 (95% CI 0.767 to 1.212). Discussion/Conclusion: Administration of ondansetron (4 mg) prior to spinal anesthesia can be recommended to help prevent the incidence of hypotension in the pregnant patient undergoing elective cesarean section. Implications for practice Anesthesia professionals utilizing ondansetron (4 mg) will realize a reduction in spinal anesthesia induced hypotension in the parturient for an elective cesarean section. This may impact patient outcomes and current practices by decreasing the adverse events associated with hypotension in this population and satisfaction in both patient and anesthesia provider.