Important Cardiovascular Formulas

Alveolar-arterial gradient = [(P_atm - P_H2O)(FIO₂) - (PCO₂/0.8)] - P_a02

Blood pressure = CO x SVR

CO = SV x HR (units: 1/min)

CI = CO/BSA (units: l/min/m²) (where BSA is the body surface area in m²)

LDL cholesterol = total cholesterol- (HDL + TG/5) (providing TG are >400 mg/dl)

Maximum predicted heart rate = 220 - age

Mean pulmonary artery pressure = 1/3 PA systolic pressure + 2/3 PA diastolic pressure

Mean systemic arterial pressure = 1/3 systemic systolic pressure + 2/3 systemic diastolic pressure

Pulmonary vascular resistance = [(mean PAP - PCWP)/CO] x 80 (units: dynes-sec-cm^-5 )

Pulse pressure = systolic BP - diastolic BP

Stroke volume = LV end diastolic volume - LV end systolic volume

Systemic vascular resistance = [(MAP - CVP)/CO] x 80 (units: dynes-sec-cm^-5 )
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BP: blood pressure
CI: cardiac index
CO: cardiac output
CVP: central venous pressure
FIO₂: percent inspired oxygen (21 % on room air)
HR: heart rate
MAP: mean arterial pressure
P_ATM : atmospheric pressure (760 mmHg at sea level)
P_H20: partial pressure of water (47 mmHg)
P_aCO₂: arterial CO, concentration
PA: pulmonary artery
PAP: pulmonary arterial pressure
PCWP: pulmonary capillary wedge pressure
SV: stroke volume
SVR: systemic vascular resistance
TG: triglycerides