Maintenance of respiratory modulation by pneumotaxic mechanisms in deep anesthesia

My purpose was to evaluate the hypothesis that the pneumotaxic center should continue to regulate ventilatory activity in deep anesthesia. In decerebrate cats, the respiratory pattern was reversibly altered from eupnea to apneusis by cooling the rostral pons. Such cooling markedly changed phrenic activity even after doses of halothane, pentobarbital, or chloralose-urethane had almost entirely eliminated this activity in eupnea. It is concluded that both pontile and medullary mechanisms control eupneic ventilatory activity in unanesthetized as well as deeply anesthetized preparations.