Comparision the Effect of Remifentanil and Alfentanil on Intraocular Pressure after Induction and During Anesthesia of Patients Undergoing Cataract Surgery

Anesthesia for ophthalmic surgery requires management of intraocular pressure (IOP) during preoperative period. Any degree of IOP increasing could reduce visual acuity. Administration of narcotics concomitant with anesthetics has the ability to reduce this increase of IOP. This clinical trial aims to compare the efficacy of Remifentanil and Alfentanil in preventing an increase in IOP after administration of succinylcholine, intubation and during anesthesia. This double blind clinical trial was intended to 50 patients undergoing elective general surgery for cataracts. Patients were randomly divided to two groups; Alfentanil (20µg/Kg in 30 second) for group 1 and Remifentanil (1µg/kg in 30 second) for group 2 were injected before induction of anesthesia and 0.5µg/kg/min Alfentanil for group 1 and 0.1µg/kg/min Remifentanil for group 2 were infused during the anesthesia. Systolic and diastolic blood pressure, heart rate and IOP from normal eye were measured before the induction, after administration of thiopental and succinylcholine, after tracheal intubation and 2 minutes later and were repeated in 2-minute intervals until the end of operation. IOP decreased after injection of anesthetics and remitted lower all through the operation in both groups, but IOP decreased after injection of succinylcholine in Remifentanil group while it increased in Alfentanil group (P<0.05). Results of this study indicate benefits of both Remifentanil and Alfentanil for managing IOP after induction and during anesthesia. It seems that Remifentanil is better than Alfentanil in controlling the IOP after injection of succinylcholine.