title: Sympathetic influence on alveolar surface activity in hyperventilated dog.
abstract: Hyperventilating IPPB, defined as intermittent positive-pressure breathing with a frequency of 32 beats/min and inspiratory pressure of 30 cmH2O, was administered for 14 h to open-chested anesthetized dogs in which nerves to one bronchus were operatively blocked. In the nerve-intact lungs, the lung stability index calculated from the pressure-volume relationship decreased with the duration of the hyperventilating IPPB (correlation coefficient r = -0.66, P less than 0.001), and atelectasis and hemorrhage appeared. In the nerve-blocked lungs, the index did not decrease during the 14 h of hyperventilating IPPB, and the appearance was almost normal. After pharmacologic sympathetic block with phenoxybenzamine, the lung stability index of both the operatively nerve-blocked lung and the nerve-intact lung was not decreased by hyperventilating IPPB. From these findings, we conclude that sympathetic block can protect pulmonary surface activity from the adverse effects of hyperventilating IPPB.
mesh_terms: D000818:Animals; D001980:Bronchi / Q000294:innervation*; D004285:Dogs; D006985:Hyperventilation / Q000503:physiopathology*; D007384:Intermittent Positive-Pressure Breathing / Q000009:adverse effects*; D008168:Lung / Q000503:physiopathology; D008170:Lung Compliance; D010643:Phenoxybenzamine / Q000494:pharmacology; D011175:Positive-Pressure Respiration / Q000009:adverse effects*; D011663:Pulmonary Surfactants / Q000502:physiology*; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000502:physiology*
chemical_list: D011663:Pulmonary Surfactants; D010643:Phenoxybenzamine