Perfusion Equations & Values

1/2” tubing prime volume

38.61 ml/ft

3/8” tubing prime volume

21.71 ml/ft

1/4” tubing prime volume

9.69 ml/ft

1 in

2.54 cm

1 kg

2.2 lbs

normal PvCO2

41-50 mmHg

normal PaCO2

35-45 mmHg

composition of room air

78% N, 21% O, 0.04% CO2

cardiac index (CI)

CO / BSA

normal arterial pH

7.35-7.45

normal venous pH

7.3-7.4

normal PaO2

80-100 mmHg

normal PvO2

40 mmHg

normal SaO2

95-100%

normal SvO2

65-75%

normal PvCO2

41-50 mmHg

normal arterial HCO3-

22-26 mmEq/L

pulmonary vascular resistance (PVR)

(MPAP - LA) 80 / CO

mean pulmonary arterial pressure (MPAP)

(1/3) systolic + (2/3) diastolic

gas diffusion formula

(SA x diffusion coefficient x partial-pressure gradient) / membrane thickness

CaO2 (vol%)

(1.36 ml O2/g Hgb x Hgb x SaO2) + (0.0031 x PaO2)

DO2

CO x CaO2 x 10 = ml O2/min

DO2i

CI x CaO2 x 10 = ml O2/min/m^2

VO2

CO x 10 x Hgb x 1.36 ml O2/g Hgb x (SaO2 - SvO2)

DuBois Body Surface Area

(height in cm)^0.725 x (weight in kg)^0.425 x 0.007184

tachycardia

HR >100bpm

prime volume formula

V = length x pi x r^2