130. EFFECT OF DECOMPRESSION ON INTERNAL PRESSURES: DOG 



Unprotected dogs decompressed from 100-200 ft equivalent depth with trachea closed, developed pulmonary interstitial 

 emphysema and air embolism when intratracheal pressure reached a critical level of approximately 80 mm Hg. 

 However, it appears that the critical factor in this development is a transpulmonic pressure of 60-70 mm Hg, or a 

 transatrial pressure in excess of 55-65 mm Hg, rather than an absolute level of the intratracheal pressure. Over- 

 distension of the lung was prevented by application of thoraco-abdominal binders, but not by abdominal binders 

 alone. Group A = animals without binders that developed air embolism; Group B = animals without binders that did 

 not develop air embolism; Group C = animals with abdominal binders that developed air embolism; Group D = 

 animals with thoraco-abdominal binders that did not develop air embolism. Values represent pressures in mm Hg 

 based on means of all animals weighted by the number of ascents. 



III Transpulmonary = intratracheal minus intrapleural. /2/ Transatrial = intratracheal minus left atrial. 

 /3/ Transcapillary = pulmonary arterial minus left atrial. 



Contributor; Schaefer, K. E. 



Reference ; Schaefer, K. E., McNulty, W. P., Jr., Carey, C and Liebow, A. A., J. Appl. Physiol., in press. 



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