Aa.gradient.cal: Calculates the alveolar-arterial gradient.

In CCVR/inteRn: What the package does (short line)

Description

Calculates the difference in partial pressure of oxygen between the alveolus and arteries.

Usage

Aa.gradient.cal(
  age = 81,
  FiO2 = 0.4,
  PaO2 = 146.3,
  PaCO2 = 33.2,
  Patm = 760,
  R = 0.8, 
  PH2O = 47
)

Arguments

age	Accepts an integer value (numerical value also accepted). The patient's age, in years. The function will accept any integer value, but the values should be between 1-120.
FiO2	Accepts a numerical value. The fraction of inspired oxygen. The function will accept any numerical value, but the result will be nonsense if its not between 0-1. The FiO2 is 0.21 in room air. If the patient is on mechanical ventilation, please use the FiO2 parameter on the ventilator. Similarly, if the patient is on v-mask or nasal canula, please use the fraction of oxygen provided. For example, if the patient is on 70 percent oxygen via v-mask, please use 0.70.
PaO2	Accepts a numerical value. The partial pressure of oxygen in arterial gas. Please use the reported PaO2 on arterial blood gases.
PaCO2	Accepts a numerical value. The partial pressure of CO2 in arterial gas. Please use the reported PaCO2 on arterial blood gases.
Patm	Accepts a numerical value. The atmospheric pressure in mmHg. The default is 760 (at sea level).
R	Accepts a numerical value. The respiratory quotient. Generally a constant variable. Shouldn't be changed unless you understand what you are doing.
PH2O	Accepts a numerical value. Partial pressure of water vapor. Default is 47.

Value

Returns a numerical value. The value corresponds to the alveolar-arterial gradient.

Author(s)

Carlos C Vera Recio

References

Helmholz HF Jr. The abbreviated alveolar air equation. Chest. 1979 Jun;75(6):748

Examples

Aa.gradient.cal(
  age = 81,
  FiO2 = 0.4,
  PaO2 = 146.3,
  PaCO2 = 33.2,
  Patm = 760,
  R = 0.8, 
  PH2O = 47
)

CCVR/inteRn documentation built on Dec. 17, 2021, 12:51 p.m.