Comparison of induction time and characteristics between sevoflurane and sevoflurane / nitrous oxide

A previous investigation using nitrous oxide with 5% enflurane (3.8 MAC) for single breath induction produced a stage of excitement which may be related to the difference in blood/gas coefficient solubility of these agents. The closer blood/gas solubility coefficient of sevoflurane and nitrous oxide may eliminate this phenomenon. We therefore evaluated 40 volunteers in a randomized study using 7.5% sevoflurane (3.7 MAC) in oxygen (n = 21) or sevoflurane with nitrous oxide (n = 19) using a single breath induction technique. Sevoflurane in nitrous oxide and oxygen reduced induction time by 15% compared to sevoflurane in oxygen alone (41 +/- 16 and 48 +/- 16 sec (s.d.), respectively). This was, however, not statistically significant. There were scarcely induction-related complications, such as coughing, laryngospasm, breath-holding, movements of a limb and excessive salivation, in either group. Thus, the addition of nitrous oxide neither increased the number of complications, nor the speed of induction.