Comparing prophylactic effect of phenylephrine and ephedrine on hypotension during spinal anesthesia for hip fracture surgery

Background: Spinal anesthesia is an accepted technique in hip fracture surgery and prevention of this complication by sympathomimetic agents is of potential clinical significance. The aim of this study is to compare the effect of prophylactic phenylephrine versus ephedrine in the prevention of hypotension during spinal anesthesia in hip fracture surgery.
Materials and Methods: Ninety-two patients undergoing hip fracture surgery with the American Society of Anesthesiologists I and II were randomized to receive prophylaxis with ephedrine or phenylephrine immediately before the spinal anesthesia. Patients in the ephedrine group received an intravenous (IV) bolus of 10 mg ephedrine, and patients in the phenylephrine group received an IV bolus of 50 μg phenylephrine. We recorded mean arterial pressure (MAP), systolic and diastolic blood pressure, heart rate every 3 min in the first 10 min and then every 5 min until 30 min after spinal anesthesia, nausea and vomiting, additional vasopressor, and atropine administration.
Results: The frequency of hypotension was significantly lower in MAP, systolic and diastolic pressure in group phenylephrine in 3, 6, and 9 min after spinal anesthesia (P = 0.002, P = 0.001). There were no significant differences between two groups in heart rate at different time of study. In the phenylephrine group, lower additional vasopressor was used (8.7% and 23.9%) (P = 0.04). There were no significant differences between two groups in the use of atropine (P = 0.24), nausea and vomiting.
Conclusion: At the doses of ephedrine and phenylephrine administered in this trial, phenylephrine was better to prevent hypotension during hip fracture surgery with spinal anesthesia. Higher frequency of hypotension was observed in the ephedrine group.