Cardiovascular Formulas and Parameters




INTRODUCTION



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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





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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





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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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Jan 14, 2019 | Posted by in PEDIATRICS | Comments Off on Cardiovascular Formulas and Parameters

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