Objective and Subjective Impairment from Often-Used Sedative/Analgesic Combinations in Ambulatory Surgery, Using Alcohol as a Benchmark

Impairment caused by different sedative/analgesic combinations commonly used in ambulatory settings was compared to that of alcohol at blood alcohol concentrations (BACs) higher than or equal to 0.10%. Impairment was measured via subjective (mood) and objective (psychomotor performance) assays. Twelve healthy human volunteers (10 males and 2 females; age range 21-34 yr) participated in this prospective, double-blind, randomized, cross-over study. Each subject was exposed to five drug conditions across 5 wk. Each of the following drug conditions were adjusted for body weight (per 70 kg)fentanyl 50 micro gram and propofol 35 mg (FP), fentanyl 50 micro gram and midazolam 2 mg (FM), fentanyl 50 micro gram, midazolam 2 mg, and propofol 35 mg (FMP), alcohol 56 g (orally administered), and placebo (PLC). With the exception of alcohol, the other drugs were administered via the intravenous route. Tests for psychomotor performance, subjective effects, and short-term memory were done at baseline, and at different intervals until 240 min postinjection. Psychomotor impairment caused by alcohol at 15 min postingestion (at a BAC of 0.11% +/- 0.03% [mean +/- SE]) was used as a benchmark with which impairment caused by other sedative/analgesic combinations was compared. All the study drug combinations produced impairment (i.e., impairment greater than that seen with PLC), similar to that observed with alcohol at a BAC of 0.11%. We have demonstrated that some sedative/analgesic drug combinations used in anesthesia for ambulatory procedures produce impairment similar to or greater than that observed with a large dose of alcohol.(Anesth Analg 1995;80:1092-8)