Comparison of Hypobaric Bupivacaine, With and Without Fentanyl for Patients Undergoing Surgeries around Hip: A Randomized Double Blind Study from North India

Hypobaric Bupivacaine for Patients Undergoing Surgeries around Hip

Abstract

Background: Hip surgeries are frequently performed using single shot spinal anesthesia with 15-17.5 mg plain bupivacaine 0.5% which provides surgical anesthesia for 3-4 hours but is difficult to make the patients with hip fractures to lie in lateral decubitus position with the operating side dependent and to make them sit also. Using hypobaric local anesthetic for surgeries around hip, preparation time may be reduced for performing spinal anesthesia and surgery in the same position without waiting for establishment of spinal anesthesia in the supine position. Furthermore, hypobaric local anesthetics can produce more selective block on the operating side and avoid unnecessary paralysis of the nonoperating side potentially resulting in hemodynamic stability and better mobilization of patients during recovery period.Subjects and Methods:In the present study, we compared the anesthetic and hemodynamic effects of hypobaric bupivacaine with and without fentanyl in 100 ASA physical status I and II patients undergoing surgeries around hip. Patients received spinal injection of either 2.5ml (12.5mg) of isobaric bupivacaine with 1.5ml of distilled water (total 4ml) making it hypobaric or 2.5 ml (12.5mg) of isobaric bupivacaine with 1ml of distilled water and 0.5ml(25 g) of fentanyl (total 4ml) with operative side up, in a double blinded manner. Sensory level and motor block were evaluated on the operative and non-operative sides until regression to L2 and full motor recovery. Hemodynamic changes after spinal injection and the first analgesic request for VAS >3 were noted.Results:Demographic characteristics of both the groups were comparable. Time to maximal fall in MAP and patients requiring vasopressor were similar in both the groups. None of the patients in any of the two group required atropine for bradycardia. Co-administration of fentanyl in hypobaric bupivacaine hastened the onset of sensory block (123 vs. 209.0, p value <0.001) and the time required was less on the operative side than on the contralateral (non-operative) side in both the groups. The median upper level of block was higher on the operative than on the contralateral side in both the groups. Co-administration of fentanyl in hypobaric bupivacaine prolonged the sensory regression to L2 (29840 vs. 25635, p value <0.001). Co-administration of fentanyl had no effect on the time to complete motor recovery as at the end of surgery, all the patients had complete motor recovery on the contralateral (non-operative) side, while none of the patient in any of the two groups had complete motor recovery on the operative side. Time to first analgesic requirement was significantly higher (31827 vs. 28828, p value <0.001) with the addition of fentanyl to the hypobaric bupivacaine.Conclusion:So we conclude that the use of hypobaric bupivacaine produces spinal anesthesia with a faster sensory motor recovery on the contralateral (non-operative) side. Co-administration of fentanyl further prolongs the sensory block on the operative side without significantly affecting the motor block, so delays the use of first analgesic without further compromising the systemic hemodynamics.