A Comparison of Labetalol and Nitroglycerin for The Management of Intraoperative Hypertension in Ambulatory Surgical Patients Who Underwent Cataract Surgery

Abstract

Background: This is a prospective randomized blinded clinical trial comparing the efficacy and safety of labetalol and nitroglycerin for the management of intraoperative hypertension in ambulatory surgical patients who underwent cataract surgery.
 Methods: A total of 80 hypertensive patients (systolic blood pressure> 200 mmHg or diastolic blood pressure>100 mmHg) who had increased blood pressure during cataract surgery under topical anesthesia were reviewed. Patients were randomized to receive nitroglycerin (group N, n=40) or labetalol (group L, n=40). The initial dose of nitroglycerin was a bolus of 2 µg/kg and repeat dose of 1ug/kg intravenously every 5 minutes. Labetalol was administered as a bolus of 5 mg followed by 5 mg intravenously as needed every five minutes up to maximum dose of 1 mg/kg.
 Results: Systolic blood pressure decreased from 21.4±8.6 mm Hg (200 to 260 mm Hg) to 18.8±6.4 mm Hg with administration of nitroglycerin. Labetalol reduced systolic blood pressure from 21.4±6.7 mm Hg (201 to 258 mm Hg) to 17.6±11.6 (p=0.02). Nitroglycerin increased baseline heart rate from 68±8 beats/min to 82±6 beats/min (p=0.04), however, in the labetalol group heart rate reduced from control 72±6 to 64±9 beats/min (P<0.05). The hypotension episode was 18 (45%) cases in the nitroglycerin group and 2 (5%) cases in the labetalol group respectively (p<0.05). The mean of systolic blood pressure during their stay in the recovery room in nitroglycerin group was 20.7±9.6 mm Hg and in labetalol group was 18.5±10.2 mm Hg (p<0.05).
 Conclusion: Nitroglycerin may produce reflex tachycardia and episode of hypotension especially in elderly patients intraoperatively. Labetalol is a safe and effective antihypertensive agent for management of increased blood pressure during cataract surgery with topical anesthesia.