GAS EXCHANGE DIAGRAM April Apperson, UCSD SOM OESS Dry air P Gas = F Gas •P B (atmospheric) P O2 = F O2 •P B P CO2 = F CO2 •P CO2 Inspired air P I-Gas = F Gas •(P B- P H2O ) P IO2 = F O2 •(P B- P H2O ) Ventilation (L/min) ˚V E = n(V T ) V T = V A + V D n(V T – V D ) =˚V A = (˚V C02 •K)/P ACO2 P ACO2 ≈ ˚V CO2 /˚V A P AO2 = P IO2- P ACO2 /R Pc’ O2 Pc’ CO2 R = ˚V CO2 /˚V O2 •0.8 at rest •1.0 with exercise CO 2 diffusion rate = D L-CO2 (Pc CO2- P AO2 ) O 2 diffusion rate = D L-O2 (P AO2- Pc O2 ) O 2 diffusion limitations: •Exercise at low P AO2, e.g. at high altitude •Exercise with moderate fibrosis or at rest with severe fibrosis •Max exercise at sea level for trained athlete 1/D L = 1/D M + 1/( θ •V c ) D M ≈ (Sol G )•[(SA)/T] barrier P a O2 %S Hb C a O2 = (%S Hb )[Hb](1.39) + (Pa O2 )(.003) Ca O2- Cv O2 = ˚V
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This note was uploaded on 09/14/2011 for the course PHARM ps taught by Professor Staff during the Spring '11 term at UCSD.