Pattern of respiration in patients recovering from barbiturate overdose.

Ventilation has been recorded in seven patients who were unconscious following self-poisoning. Measurements were obtained on admission to the hospital and repeated daily until the patients regained consciousness. On admission, recordings were characterized by a low minute ventilation as a result of a low tidal volume in spite of a high frequency of respiration. During the period of recovery tidal volume and minute ventilation increased, whereas frequency decreased. The modifications observed during recovery were the reverse of those noted during the induction of anaesthesia wih barbiturates in man. However, these modifications differ from those observed during induction of anaesthesia in cats. Consequently, as far as respiratory control is concerned, models elaborated in animals cannot be extrapolated to deeply anaesthetized human subjects.