A Comparative Study of Three Vasopressors for Maintenance of Blood Pressure during Spinal Anesthesia in Lower Abdominal Surgeries

INTRODUCTION: Subarachnoid block, although being highly efficient with lesser drug doses, often has limitation such as hypotension, continues to be a matter of concern to the anesthetist. The present study was aimed to compare the use of phenylephrine, ephedrine, and mephentermine bolus for maintenance of blood pressure during spinal anesthesia in lower abdominal surgeries. SUBJECTS AND METHODS: In a randomized, prospective study, 90 adult patients of either sex who developed hypotension during surgery under subarachnoid block were allocated into three groups to receive bolus phenylephrine, ephedrine, and mephentermine. The number of boluses and time taken to recover from hypotension was noted. Occurrence of adverse effects in the perioperative and postoperative period was also noted. RESULTS: Results were analyzed by Student's paired t-test and Chi-square test. The ANOVA test was used to compare the group variances among the study groups. P < 0.05 was considered statistically significant. Thirty-four hypotensive events (average 1.03 events/patient) took place in mephentermine group. In phenylephrine group, a total of 53 hypotensive events took place. On an average, the group had a total of 1.61 hypotensive events per patient. No hypotensive event took place in ephedrine group after the first bolus of drug (average 1 event/patient). Mean heart rate in phenylephrine group was significantly lower as compared to the other two groups (P < 0.001). CONCLUSION: Mephentermine and ephedrine were similar in performance, offered a better hypotensive control, and had lower recurring events as compared to phenylephrine.