Canadian Anaesthetists’ Society Journal

, Volume 25, Issue 6, pp 488–494 | Cite as

Subanaesthetic halsothane: Its effect on regulation of ventilation and relevance to the recovery room

  • A. W. Gelb
  • R. L. Knill


Ventilation and the ventilatory response to a steady-state of isocapnic hypoxaemia were measured in six healthy volunteers, both awake and while sedated with low doses of halothane (0.05 and 0.1 MAC). Halothane sedation markedly reduced ventilatory responses to sustained hypoxaemia, in a dose-related fashion.

We estimated the length of time after anaesthesia that halothane 0.1 MAC would be present in patients in the recovery room. In five healthy patients who had halothane anaesthesia with a mean duration of one hour, halothane 0.1 MAC or more persisted for approximately one hour.

We conclude that, during emergence from halothane anaesthesia, patients may have a significant impairment of the ventilatory response to hypoxaemia, which persists for some time even after regaining consciousness.


Halothane Recovery Room Ventilatory Response Minimum Alveolar Concentration Halothane Anaesthesia 


Chez six volontaires en bonne santé tantôt éveillés, tantôt sous sedation légère à faible dose ďHalothane (0,05 et 0,1 MAC), on a mesuré la ventilation et la réponse ventilatoire à ľhypoxémie isocapnique soutenue. Proportionnellement à la dose administrée, ľHalothane a fortement réduit la réponse ventilatoire à ľhypoxémie soutenue.

Dans un deuxième temps, nous avons cherché à estimer combien de temps, au sortir ďune aneslhésieà ľHalothane, on peut encore déceler en salle de réveil des concentrations ďHalothane de ľordre de 0,1 MAC. Chez cinq malades en bonne santé pour une heure ďanesthésie à ľHalothane, des concentrations de 0,1 MAC ou plus ont persisté en salle de réveil pendant à peu près une heure.

Nous en concluons qu’au sortir ďune anesthésie à ľHalothane, la réponse ventilatoire à ľhypoxémie peut être nettement réduite et que ce phénomène persiste même après le retour à la conscience.


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Copyright information

© Canadian Anesthesiologists 1978

Authors and Affiliations

  • A. W. Gelb
    • 1
  • R. L. Knill
    • 2
  1. 1.Department of AnaesthesiaUniversity of TorontoCanada
  2. 2.Department of AnaesthesiaUniversity Hospital, University of Western OntarioLondonCanada

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