Effect of sevoflurane concentration on inhalation induction of anaesthesia in the elderly.
We have conducted a randomized, double-blind comparison of 4% and 8% sevoflurane for induction of anaesthesia in unpremedicated patients aged more than 60 yr. Sevoflurane was inhaled in 50% nitrous oxide using a vital capacity breath technique, and mean, systolic and diastolic arterial pressures and heart rate were monitored continuously using a Finapres cuff. In the 8% sevoflurane group, time to successful laryngeal mask insertion was significantly shorter (mean 168 (SD 34) s vs 226 (62) s; P < 0.01) and achieved more often at the first attempt than in the 4% sevoflurane group. Arterial pressures were lower in the 8% group, but this was not significant. No patient had apnoea lasting longer than 1 min. A total of 69% of patients described induction as pleasant and 85% would choose to have it again. We conclude that compared with 8% sevoflurane, the use of 4% sevoflurane in the elderly resulted in greater cardiovascular stability but at the cost of prolonged and occasionally unsuccessful induction.
D000368:Aged; D000369:Aged, 80 and over; D000769:Anesthesia, Inhalation / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000008:administration & dosage* / Q000494:pharmacology; D008875:Middle Aged; D017060:Patient Satisfaction; D000077149:Sevoflurane; D013997:Time Factors