TITLE: COMPARISON OF REMIFENTANIL VERSUS ISOFLURANE GENERAL ANESTHESIA FOR SHORT OUTPATIENT UROLOGIC PROCEDURES

AUTHORS: A.L. Kovac, MD, K. Summers, SRNA, C. Elliott, CRNA, H. Mathewson, MD
AFFILIATION: University of Kansas Medical Center, Kansas City, KS.

INTRODUCTION: Patient emergence, extubation and discharge from the operating room (OR) and postanesthesia care unit (PACU) are important time points for recovery of outpatients receiving general anesthesia.
PURPOSE: To compare the effect of remifentanil versus isoflurane anesthesia on Aldrete scores, emergence, extubation and discharge times from OR and PACU following short outpatient urologic procedures (P&C, bladder dilatation, stent placement).
METHODS: Following IRB approval and written informed consent, 40 ASA physical class 1-3 adult outpatients were enrolled in this randomized, prospective, single-blind study. Study subjects were equally divided (n=20 each) into remifentanil and isoflurane groups. All subjects received intravenous (IV) midazolam 1-2mg preoperatively and were induced with propofol 2mg/kg IV. Muscle relaxation was with succinylcholine, rocuronium or cisatracurium. The remifentanil group received 1mg/kg IV at induction and a maintenance dose of 0.1 to 2mg/kg/min IV in the presence of 60% N₂O/40% O₂ and end-tidal isoflurane of 0.4% (for amnesia). The isoflurane group received fentanyl 1-2mg/kg IV at induction, maintenance of fentanyl 2-3mg/kg IV, and titration of 1-2% end-tidal isoflurane with 60% N₂O/ 40% O₂. Muscle relaxation was reversed at the end of anesthesia as needed. Times for OR entry, emergence, extubation, total OR (entry to exit) and PACU discharge, as well as Aldrete scores at time of OR exit and PACU discharge were determined. Data was evaluated by ANOVA, t-test and Chi square test. A p<0.05 value was considered statistically sig- nificant.
RESULTS: There was no significant difference between groups in age, gender, weight, ASA class, PACU analgesic or antiemetic use, or times of emergence, extubation, OR exit and PACU discharge. There was a significant difference (p<0.05) in OR exit Aldrete scores but not PACU discharge Aldrete scores (Table). No adverse effects were noted.
CONCLUSIONS: While there was no difference between the remifentanil and isoflurane groups regarding recovery time points from OR and PACU, remifentanil patients had significantly better OR exit Aldrete scores with less sedation than the isoflurane group. This may prove helpful for fast-track eligibility of these patients.

Op=operation *p<0.05 compared to isoflurane group
Extub=Extubation Data values = mean±SD