Interaction Between the Mechanical Properties of the Respiratory System and Drive in the Control of Breathing of Anesthetized Man
Anesthesia induces changes in the mechanical characteristics of the respiratory system and in the ventilatory control setting. Since ventilation depends not only on neural output and muscle contraction but also on the impedance of the system, one could assume that mechanical and ventilatory modifications could interact. It is well known that both passive1, 2 and effective elastance3 are increased under anesthesia. Yet there is still some controversy about the time course of these changes. On the other hand, sighs or augmented big breaths have been reported to be scarce, and this low frequency of periodic inflation of the lungs is assumed to be responsible at least for part of the increased elastance of the lungs4. In the present study, we have investigated the time course of the changes in the mechanical properties of the respiratory system and the nature and frequency of sighs in the awake and anesthetized state.
KeywordsTidal Volume Respiratory Muscle Ventilatory Response Inspiratory Flow Occlusion Pressure
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