48. RESPIRATORY DEAD SPACE AND CHANGE IN FUNCTIONAL RESIDUAL CAPACITY: DOG 

 Determinations made on 11 dogs; tidal volume was held constant at iOO ml and rate at 10 or 12 respirations per min. 

 Anatomic dead space is proportional to end inspiratory lung volume, while physiologic dead space is approximately 

 constant over range of lung volumes studied. For definitions and clarifying information on various dead space con- 

 cepts, see Page 46. 



100 r- 



80 



. 60 



a 



40 



ZO 



physiologic dead space 

 anatomic dead space 



Pneumothorax 

 _i I > L 



Normal 



I I 



Distended 



_L 



_!_ 



-300 -200 -100 +100 +200 



Change in Functional Residual Capacity, ml 



+ 300 



Contributor : Severinghaus, J. W. 



Reference : Severinghaus, J. W., and Stupfel, M., J. Appl. Physiol. ^:335. 1957. 



Male subjects. V 



D 



49. SOME FACTORS AFFECTING RESPIRATORY DEAD SPACE: MAN 



Part I: EFFECT OF BREATHHOLDING 

 volume of dead space gas. For definitions and clarifying information on various dead space 



concepts, see Page 46. 



/I/ Foreign gas method (hydrogen), 

 method (Lilly nitrogen meter). 



/2/ Nitrogen method (Lilly nitrogen meter). /3/ Recording mass spectrometer 



48 



