Single breath induction of anaesthesia, using a vital capacity breath of halothane, nitrous oxide and oxygen.

Inhalational induction of anaesthesia, using a single vital capacity breath of 4% halothane in 66% nitrous oxide and 33% oxygen was evaluated in 100 unpremedicated outpatients. The technique was found to be acceptable to most (91%) of the patients studied, with a mean (SD) induction time (measured from beginning of inspiration to loss of 'eyelash reflex') of 83(21) seconds. Relative cardiovascular stability was a notable finding of the technique, with a slight decrease in the mean arterial pressure of only 10%. Anaesthetic induction time was unaffected by age, weight or smoking habits. The technique of single breath induction is therefore proposed as a safe and acceptable alternative to intravenous induction in co-operative adult patients.