INTRODUCTION
Arterial oxygen content of the blood:
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0.003*PaO2 represents the fraction of dissolved oxygen in the blood
Venous oxygen content of the blood:
Arterial-mixed venous oxygen content difference:
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CaO2 ∼20 mL/dL
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CvO2 ∼15 mL/dL
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Oxygen extraction is approximately 25%; it can also be estimated by:
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SaO2 − SvO2
Cardiac Output: CO = HR × SV Units: | L/min |
Cardiac Index: CI = CO/BSA in m2 | Nl 3.6 – 6 L/min/m2 |
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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
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If you don’t multiply by 79.9, then use Woods units OR mmHg/L/min
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PAP – Pulmonary artery pressure
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PAOP – Pulmonary artery occlusion pressure
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MAP – Mean arterial pressure
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RAP – Right atrial pressure
SVR Index: SVRI = SVR/BSA | Nl: 800 to 1600 dyne-s/cm5/m2 |
PVR Index: PVRI = PVR/BSA | Nl: 80 to 240 dyne-s/cm5/m2 |

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