## INTRODUCTION

Arterial oxygen content of the blood:

$CaO2(mL O2​/dL)=(SaO2× Hemoglobin × 1.36) + 0.003*(PaO2)$
• 0.003*PaO2 represents the fraction of dissolved oxygen in the blood

Venous oxygen content of the blood:

$CvO2(mL O2​/dL)=(SvO2× Hemoglobin × 1.36) + 0.003*(PvO2)$

Arterial-mixed venous oxygen content difference:

$avDO2=CaO2−CvO2$
• CaO2 ∼20 mL/dL

• CvO2 ∼15 mL/dL

• Oxygen extraction is approximately 25%; it can also be estimated by:

• SaO2 − SvO2

 Cardiac Output: CO = HR × SV Units: L/min Cardiac Index: CI = CO/BSA in m2 Nl 3.6 – 6 L/min/m2

• CI more used for children as it normalizes for size

Oxygen Delivery: DO2 = CO × CaO2 × 10

Oxygen Consumption: VO2 = CO × (CaO2 − CvO2) × 10

Oxygen Extraction Ratio: O2ER = VO2/DO2 = [(CaO2 − CvO2)/CaO2]

Pulmonary Vascular Resistance: PVR = (PAP − PAOP)/CO × 79.9 dynes*sec/cm5

Systemic Vascular Resistance: SVR = (MAP – RAP)/CO × 79.9 dynes*sec/cm5

• If you don't multiply by 79.9, then use Woods units OR mmHg/L/min

• PAP – Pulmonary artery pressure

• PAOP – Pulmonary artery occlusion pressure

• MAP – Mean arterial pressure

• RAP – Right atrial pressure