Remifentanil-Ketamine versus Fentanyl-Ketamine sedation in patients undergoing phacoemulsification with topical anesthesia: comparison of intraocular pressure changes and sedation quality

Background: narcotics and sedatives can reduce intraocular pressure. this study was performed to evaluate the effectof remifentanil plus ketamine on intraocular pressure and sedation quality in comparison with fentanyl plus ketamineduring and after operation in patients undergoing phacoemulsification with topical anesthesia.methods: forty four patients were randomized into two groups to receive either a continuous infusion ofremifentanil(0.2 ug/kg/rnin for 4 min and then 0.1 ug/kg/min: group r, n=22) or bolus intravenous fentanyl (1.5 ug/kg: group f,n=22) for sedation. patients in both groups received low dose ketamine (0.15 mg/kg) intravenously. topical anesthesiawas performed using tetracaine 0.5% eye drop in both eyes. intraocular pressure was measured in non-operative eyebefore sedation (baseline), 2 minutes after sedation, before intraocular lens insertion, at the end of operation and 15minutes after the end of operation using schiotz tonometer. sedation, cooperation, satisfaction and pain scores and alsopostoperative nausea and vomiting were recorded in all patients. surgeon satisfaction scores were evaluated at the endof operation.results: the intraocular pressure did not differ significantly between the two groups throughout the study. the mean(sd) intraocular pressures 2 minutes after sedation, before intraocular lens insertion, at the end of operation and 15minutes after the end of operation in recovery room were all less than that of baseline in both groups, but the baselinevalue was decreased only significantly (p(less than)0.05) in recovery room [13.75 (3.46) tol1.91 (3.43) in group r, respectivelyand 13.74 (3.05) tol1.57 (2.33) in group f, respectively]. the incidence of postoperative nausea and vomiting in groupr was higher than that of group f (7 patients in group r and no patient in group f, p=0.009).conclusions: combination of remifentanil infusion and intravenous ketamine did not offer any advantages over thecombination of intravenous fentanyl and ketamine in order to prevent intraocular pressure rising during phacoemulsification.the lower incidence of postoperative nausea and vomiting and higher rate of appropriate sedation in fentanylgroup suggested fentanyl as a more suitable medication for systemic sedation compared with remifentanil