Distension of the lungs : its effect on the respiration in man and in normal and vagotomized dogs / by Walter M. Boothby and Frank B. Berry.

  • Boothby, Walter M.
Date:
[1915?]
Catalogue details

Licence: In copyright

Credit: Distension of the lungs : its effect on the respiration in man and in normal and vagotomized dogs / by Walter M. Boothby and Frank B. Berry. Source: Wellcome Collection.

    6/24 (page 436)
    through the branch of the tap leading to the room air, and at various periods in the respiratory cycle the tap was suddenly turned, so as to connect the subject with the air under pressure in the respiration apparatus. By this means the lungs were rapidly distended with air and the intra-pulmonary pressure in¬ creased by a definite amount. The spirometer of the respiration apparatus, though weighted, was perfectly free to move in either direction, so that the response of the subject to the stimulus of lung distension would be unhampered by still further changes in the intrapulmonary pressure, produced by any respiratory movements that might occur. In experiments in which the trachea is clamped or the tap entirely closed after the distension, changes in pressure would naturally follow any respiratory move¬ ments. Movements, therefore, that might be too small to be recorded by a pneumograph or even by a slip of the diaphragm could possibly produce changes in intrapulmonary pressure that would give rise to secondary and confusing reactions. In the case of the dogs, an air-tight mask was applied to the animal’s head, according to the method described by Boothby and Shamoff.8 The mask was connected to the three-way tap by rubber tubing of large bore. The dead space of the mask and tubing was about 150 cc., which was quite large in compari¬ son with the tidal volume of air. The dogs lay quietly on their sides on a table and .were unrestrained. They were perfectly comfortable and did not require anaesthesia. By means of a pneumograph around the thorax, the respira¬ tory movements were recorded qualitatively on the kymograph, both before and after the subject breathed the air under pressure. As soon as the tap was turned to the respiration apparatus a very accurate quantitative curve of the coordinated total respi¬ ratory movements was written by the recording spirometer. In Figure I is given a.typical tracing of the effect, on W. M. B., of distending the lungs by suddenly increasing the intrapul¬ monary pressure. The tap is turned at the end of a normal 8 Boothby and Shamoff: A study of the late effect of division of the pulmo¬ nary branches of the vagus nerve on the gaseous metabolism, gas exchange, and respiratory mechanism in dogs. This Journal, 1915, xxxvii.