Recovery following general anesthesia with isoflurane or enflurane for outpatient dentistry and oral surgery.

Anesthesia was induced in 120 unpremedicated, healthy patients undergoing outpatient dentistry or oral surgery with methohexital, and endotracheal intubation facilitated with succinylcholine. Anesthesia was maintained randomly with either enflurane or isoflurane in nitrous oxide and oxygen (50%) administered in a nonrebreathing circuit using spontaneous respiration. After both enflurane and isoflurane anesthesia, it took 12-13 minutes before the patients were oriented as to time and place. The patients' ability to walk along a straight line normalized significantly (p < .05) more quickly after isoflurane than after enflurane anesthesia. Long enflurane anesthesia (>90 minutes) was associated with a significantly (p < .05-p < .01) slower recovery of walking ability and of psychomotor performance in a perceptual speed test than was short enflurane anesthesia (<40 minutes). With isoflurane the speed of recovery did not depend on the duration of anesthesia. After both anesthetic techniques, 25-26% of the patients had nausea or vomited. We conclude that using spontaneous respiration recovery is faster after isoflurane anesthesia than after enflurane anesthesia and that isoflurane should be preferred to enflurane for long anesthesia of outpatients.