Influence of Alprazolam Premedication on the Occurrence of Postoperative Obstructive Apnea

Abstract

PURPOSE: Obstructive apneas can be a serious perioperative complication. Every anesthesiologist should be aware of the influence of anesthetic medications on the occurrence of such apneas. We studied the effect of an oral premedication with 0.5 mg alprazolam in patients scheduled for day-care colonoscopy. METHODS: After IRB approval and informed consent, 50 patients (ASA I-II) were included. Patients with an OSA (Obstructive Sleep Apnea) syndrome were excluded. Patients were randomized in two groups: group A received an oral premedication using 0.5 mg alprazolam and group C received a placebo. Anesthesia was performed using ketamine (single iv bolus of 0.5 mg kg-1) and a continuous infusion of propofol targeted to achieve a BIS (BISpectral Index) value between 50 and 60. Patients were on spontaneous respiration. Statistics were performed using the Mann-Whitney's test and the Fisher's test. A two-tailed P value lower than 0.05 was considered significant. Data were expressed in mean + standard deviation. RESULTS: 9 patients were excluded (4 in group A, 5 in group C) because of technical problems with recording or patient's wishes. Groups were comparable in terms of demographic data and amount of propofol administered. The recruited patients were not obese (BMI A: 24.87 + 4.2 and BMI C: 24.02 + 3.13). The AHI (Apnea Hypopnea Index which is defined by the number of apnea and hypopnea per hour) was significantly higher in group A than in Group C (A: 20.33 + 10.97, C: 9.63 + 4.67, P = 0.0003). However, these apneas never induced any significant drop in peripheral saturation in oxygen or any mandibular instability. CONCLUSIONS: Our study emphasizes that premedication with 0.5 mg of alprazolam causes an increase in obstructive apneas during at least the first two postoperative hours.