[Isoflurane in spontaneous ventilation (in orthopedic surgery: comparison with halothane)]

Isoflurane and halothane, two anaesthetics agents have been compared. Forty young and healthy patients were divided into two randomly selected group. Each of them was anaesthetized either with isoflurane or with halothane. Anaesthesia was maintained with nitrous-oxide and dextromoramide. During induction, the ventilation was spontaneous. Blood-gas, ventilation rate and tidal-volume were studied before induction, during anaesthesia and at the end of the surgery. Statistical data show a higher PaCO2 and a lower pH with isoflurane. This was increased by dextromoramide. During induction, complications occurred more after than with halothane but the emergence was better.