Cardiovascular Resistance Calculator
The Cardiovascular Resistance Calculator estimates Systemic Vascular Resistance (SVR) and Pulmonary Vascular Resistance (PVR) based on mean arterial pressure, central venous pressure, and cardiac output. This calculator helps medical professionals assess blood flow resistance and heart function. Whether you are managing a patient with hypertension, evaluating heart failure, or monitoring critical care status, this tool provides quick hemodynamic insights.
How Systemic and Pulmonary Vascular Resistance Is Calculated
Vascular resistance represents the opposition to blood flow within the circulatory system. This tool uses the standard hemodynamic formula to determine the workload on the heart.
Resistance = (Mean Pressure - Venous Pressure) ÷ Cardiac Output × 80
Where:
- Mean Pressure = Mean Arterial Pressure (MAP) or Mean Pulmonary Artery Pressure (MPAP)
- Venous Pressure = Central Venous Pressure (CVP) or Pulmonary Capillary Wedge Pressure (PCWP)
- Cardiac Output = Flow rate in liters per minute
- 80 = Conversion factor to dynes·sec·cm⁻⁵
First, calculate the pressure gradient by subtracting the venous pressure from the mean arterial pressure. This step identifies the driving force pushing blood through the vessels. Next, divide this value by the cardiac output to determine flow efficiency relative to pressure. Finally, multiply by 80 to convert the medical units to standard resistance values. This widely accepted method provides a reliable snapshot of vascular tone.
What Your Systemic and Pulmonary Vascular Resistance Means
Your result indicates the level of opposition the heart faces while pumping blood through the body or lungs. This critical measurement helps clinicians understand the "afterload" or specific workload placed on the heart muscle during each beat.
Common Resistance Ranges
- Normal SVR (800-1200 dynes·sec·cm⁻⁵): This value indicates stable vascular tone. The heart is pumping efficiently against normal pressure, suggesting effective circulation.
- High SVR (>1200 dynes·sec·cm⁻⁵): Elevated levels often mean arteries are narrowed. This increases the heart's workload and is common in hypertension, often requiring vasodilators.
- Low SVR (<800 dynes·sec·cm⁻⁵): Low values usually point to widespread vasodilation, such as in sepsis or anaphylaxis, often necessitating vasoconstrictors.
- High PVR (>130 dynes·sec·cm⁻⁵): Suggests pulmonary hypertension, which requires specific clinical management to protect right heart function.
This tool is intended for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
Continue monitoring values regularly to see how the patient responds to fluid therapy or medication adjustments.