What is the water vapor pressure used in the alveolar gas equation at body temperature?

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What is the water vapor pressure used in the alveolar gas equation at body temperature?

The water vapor pressure used in the alveolar gas equation is the saturated water vapor pressure at body temperature. At 37°C, inspired air is fully humidified in the conducting airways, so the partial pressure of water vapor in alveolar air is about 47 mmHg. This value is subtracted from barometric pressure in the alveolar gas equation (PAO2 = FiO2 × (PB − PH2O) − PaCO2 × 1.25), reflecting that the gas entering the alveoli is humidified. The standard value used at body temperature is 47 mmHg, which is why this option is correct.

The water vapor pressure used in the alveolar gas equation is the saturated water vapor pressure at body temperature. At 37°C, inspired air is fully humidified in the conducting airways, so the partial pressure of water vapor in alveolar air is about 47 mmHg. This value is subtracted from barometric pressure in the alveolar gas equation (PAO2 = FiO2 × (PB − PH2O) − PaCO2 × 1.25), reflecting that the gas entering the alveoli is humidified. The standard value used at body temperature is 47 mmHg, which is why this option is correct.

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