alveolar_PAO2_mmHg {physiology}

alveolar gas equation

Description

Estimate PAO2 in alveolus based on atmospheric pressure, fraction of oxygen in inspired air, partial pressure of carbon dioxide in the alveolus, and the respiratory quotient

Usage

alveolar_PAO2_mmHg(fi_o2 = 0.209, rq = 0.8, PACO2_mmHg = 40,
  Patm_mmHg = 760, PAH2O_mmHg = 47)

Arguments

fi_o2

fraction of oxygen in inspired gas, from 0 to 1, default reflects (dry) room air

rq

respiratory quotient, i.e., the ratio of CO2 produced to oxygen consumed, usually between around 0.7 and 1.0, but can legitimately be greater than 1.0. Default it 0.8.

PACO2_mmHg

partial pressure of CO2 in alveolus, which can be roughly approximated as the end-tidal pCO2

Patm_mmHg

atmospheric pressure in kPa

PAH2O_mmHg

partial pressure of water vapor at sea level, defaults to 6.25 kPa (47 mmHg) which is appropriate for body temperature

See Also

Other respiratory: deadspace_total

Examples

# vary RQ
rq <- seq(0.6, 1.4, 0.05)
plot(rq, alveolar_PAO2_mmHg(rq = rq))

# 100% fi_o2 at typical atmospheric pressure
alveolar_PAO2_mmHg(fi_o2 = 1)

# hyperbaric oxygen at 100%, 2 atmospheres
alveolar_PAO2_mmHg(fi_o2 = 1, Patm_mmHg = 1520)