P1100

         Physiol Bohemoslov 1977;26(5):417-23

        Effect of anaesthesia on the pattern of breathing.

        Vízek M, Paleček F.

        The pattern of breathing of male rats was studied after stimulating

        respiration with carbon dioxide at different levels of general

        anaesthesia. Anaesthesia was induced by the inhalation of halothane or

        by the i.p. injection of urethane. Ventilation values were measured in

        intubated rats in body plethysmograph. It was found that a linear

        relationship between minute ventilation and tidal volume was maintained

        during the decrease of minute ventilation due to deepening of

        anaesthesia. The slope of the relationship after stimulating respiration

        with carbon dioxide also diminished during deeper anaesthesia. The

        duration of inspiration did not alter significantly, despite marked

        changes in tidal volume. Tidal volume correlated with the duration of

        expiration at different anaesthesia levels. In vagotomized rats, the

        duration of expiration shortened as ventilation was depressed by

        deepening anaesthesia.