Table 1. Mathematical symbols.

Symbol	Description
	Arterial CO2 content
	Arterial O2 content
	End-capillary arterial CO2 content
	End-capillary arterial O2 content
	Mixed venous CO2 content
	Mixed venous O2 content
	Rate of change in mixed venous CO2 content
	Rate of change in mixed venous O2 content
	Fractional inspired O2
	R-L pulmonary shunt fraction ()
	Hemoglobin content of blood
	Barometric pressure, including conversion from STP to BTP, 863 mmHg
	O2 partial pressure at 50% saturation
	O2 partial pressure
	Arterial CO2 partial pressure
	Arterial O2 partial pressure
	Alveolar CO2 partial pressure
	Alveolar N2 partial pressure
	Alveolar O2 partial pressure
	Alveolar water vapour partial pressure, 47 mmHg
	Barometric pressure, 760 mmHg
	End-capillary CO2 partial pressure
	End-capillary O2 partial pressure
	Inspired CO2 partial pressure
	Inspired N2 partial pressure
	Inspired O2 partial pressure
	Mixed venous O2 partial pressure
	Mixed venous CO2 partial pressure
	Rate of change in alveolar CO2 partial pressure
	Rate of change in alveolar N2 partial pressure
	Rate of change in alveolar O2 partial pressure
	Arterial volume
	Blood volume
	Blood volume for CO2
	Blood volume for O2
	Venous (and tissue) volume
	Venous (and tissue) volume for CO2
	Venous (and tissue) volume for O2
	Cardiac output
	Pulmonary blood flow
	Respiratory exchange ratio ()
	O2 saturation
	Arterial O2 saturation
	End-capillary arterial O2 saturation
	Mixed venous O2 saturation
	Rate of arterial O2 desaturation
	Average from t = 0–10 s during apnea
	Peak instantaneous (‘linear’) during apnea; stage 1
	during stage 2
	Rate of mixed-venous O2 desaturation
	Arterial transit time
	Lung volume
	Metabolic CO2 production
	Metabolic O2 consumption
	Expired alveolar ventilation
	Inspired alveolar ventilation
	Pulmonary CO2 uptake (from capillary to alveoli)
	Pulmonary O2 uptake (from alveoli to capillary)
	Net pulmonary gas uptake from alveoli to capillary
	Capacitance co-efficient of blood for CO2
	Capacitance co-efficient of blood for O2 relating changes in to changes in
	Capacitance co-efficient of hemoglobin for O2; slope of the O2-dissociation curve relating changes in to changes in