COMPARISON OF REMIFENTANIL WITH ALFENTANIL FOR INTUBATION IN ADULTS

Abstract

S1 Alfentanil 50 mcg kg-1 has been shown to provide similar conditions for intubation compared with succinylcholine 1mg kg-1. Remifentanil is a new, potent opioid which has a rapid onset and due to rapid metabolism by plasma cholinesterase has a half life of only eight minutes. The aim of this study was to determine if an equipotent dose of remifentanil would provide the same intubating conditions as alfentanil 50mcg kg-1 compared with succinylcholine 1mg kg-1. METHODS: With IRB approval and informed written consent, 40 ASA 1 or 2 patients undergoing general anesthesia and elective orotracheal intubation were studied. All patients were premedicated with midazolam 0.03mg kg-1 iv. Routine monitoring was instituted and the patient preoxygented. Anesthesia was induced with propofol 2mg kg-1 and each patient was randomly allocated to one of three groups. Group S received succinylcholine 1mg kg-1, group A received alfentanil 50mcg kg-1 and group R remifentanil 2mcg kg-1. One minute after administering the preprepared study drug, a blinded anesthesiologist intubated the patient and scored the technique using a three point scale for the following criteria: jaw opening, ease of laryngoscopy, vocal cord position, vocal cord movement, ease of intubation, airway reaction and movement of limbs. Intubation conditions were scored overall as: 0) unable to intubate, 1) poor, 2) fair, 3) good and 4) excellent. Succinylcholine was given if intubation was not possible. Once the intubation had been scored the code was broken to allow the anesthetist to administer drugs appropriate for the remainder of the anesthetic. RESULTS: There was no difference in the demographic data between the three groups. More patients coughed in Group R (n=13), compared with group S (n=14), and A (n=13) (10, 1 and 3 respectively, P=0.0003, Fisher's exact test) and had vocal cord movement (6, 0 and 1 respectively, P=0.003). The number of patients who had intubating scores 3 and 4 in each group were; group S: 14, group A: 12, and group R: 3 (P=0.002,). CONCLUSIONS: Intubation conditions using remifentanil 2mcg kg-1 were significantly worse compared with alfentanil or succinyl choline. This was probably due to a rapid decrease in plasma concentration as a result of the rapid metabolism of remifentanil compared with alfentanil.