Propofol decreases ocular pressure in outpatients undergoing trabeculectomy

Abstract

Study Objective: To examine the effect of a continuous low-dose intravenous (IV) infusion of propofol on ocular pressure in outpatients undergoing trabeculectomy. Design: Randomized, prospective study. Setting: Teaching hospital. Patients: 40 unpremedicated outpatients with history of primary open angle glaucoma undergoing trabeculectomy. Interventions: In the operating room, an infusion of 5% dextrose into a peripheral vein was started. The propofol group (n = 20) received 0.5 mg/kg IV propofol bolus followed immediately by a continuous 0.5 mg/kg/hr infusion. The control group (n = 20) received only the dextrose solution. A peribulbar block was performed with bupivacaine with added adrenaline, plus lidocaine. The ocular pressure (tonometer) on the eye undergoing trabeculectomy and the other eye, blood pressure (BP), and heart rate (HR) were measured at the following times: (1) preoperatively; (2) 2 minutes; (3) 5 minutes; (4) 10 minutes; (5) 15 minutes after propofol bolus administration for the propofol group (approximately 4 minutes after the peribulbar blockade on the eye undergoing surgery for the propofol and control groups). Measurements and Main Results: Ocular pressure decreased 2 minutes after propofol infusion ( p < 0.0001) and remained significantly lower than in the control group throughout the study period. All patients remained awake and cooperative during all procedures. Mean BP and HR were kept constant throughout the study. Conclusion: Low-dose propofol sedation resulted in a decrease in ocular pressure, was quick in onset, and was unrelated to BP and HR. The decrease in ocular pressure may be due to relaxation of extraocular muscles by propofol.