APPENDIX V. RESPIRATORY EQUATIONS (Concluded) 



II. Alveolar gas equations: 

 'co. 



IfVlrOj = 0, 



O) Paoj = Fioj(Pb-Pahjo)-Pacoj 



Fir 



(l-FiOj) 

 Ra 



(4) Pao^ = Pio^- 



•SfiSVojd-Fioj) 

 Va 



-FIqjxPacOj- 



IfVlrn >0, 



(5) Pao, 



Pio,R+Paco, Flo (1 -R) + Pico,- Paco, 



Ficoja-R)+R 



III. Alveolar ventilation equations (Vlj-Q = 0): 



(6) Va = (Vt - VD)f. 

 Vcoj 



(7) Va =. 



(8) Va = 



Fa, 



Ra 



Vo, 



Fa, 



(9) Va = (Pb- Pahjo)- 



Ra 



PAr 



Vo, 



[11 



[2] 



[2] 



[1] 



[1] 



[1] 



[1] 



In equations ('i)-(9), Va and VCO2 are under the same conditions and in the same units. However, 

 the general condition for VcOj is at STPD and for Va at BTPS. If, furthermore, we express the 

 former in ml/min and the latter in L/min and change Fa^o, t° PAco,. "« *<»'« customary units 

 for all parameters at any barometric pressure. After these changes, equation (7) becomes 



Vco,(ml/min, STPd) x .863 



(10) Va (L/min, BTPS) = , and [2] 



PAcOj 



X .863 



[2] 



(II) Va = 



Vo, X R X .863 



Pa, 



IV. Respiratory dead space equations: 



Va 



(12) Va = (Vt ). 



f 



Bohr Equation using any gas x (at BTPS ): 



(Fe,-Fa.) 



[1] 



Vt. 



[1] 



(13) Vd. =- 



(Fi, -Fa.) 



Contributors: (a) Swann, M. G., (b) Cassin, S. W. 



References : [ll Comroe, J. H., Jr., et al. Fed. Proc. 9:602, 1950. [2] Rahn, H., and Fenn, W. 0., "A 

 Graphical Analysis of the Respiratory Gas Exchange: The O2 - CO2 Diagram," Washington, D. C: 

 The American Physiological Society, 1955. 



391 



