1. What is Total Peripheral Resistance (TPR)?

Total Peripheral Resistance (TPR) is the resistance to blood flow offered by all of the systemic vasculature, excluding the pulmonary vasculature. It represents the total opposition to blood flow through the systemic circulatory system.

2. How Does the Calculator Work?

The calculator uses the TPR formula:

Where:

• \( \Delta P \) — Pressure difference (mmHg)
• \( Q \) — Cardiac output (L/min)

Explanation: TPR is calculated by dividing the pressure gradient (typically mean arterial pressure minus central venous pressure) by the cardiac output.

3. Importance of TPR Calculation

Details: TPR is a crucial hemodynamic parameter that helps assess vascular tone, diagnose hypertension, evaluate cardiovascular function, and guide treatment decisions in various clinical conditions.

4. Using the Calculator

Tips: Enter pressure difference in mmHg and cardiac output in L/min. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What are normal TPR values?
A: Normal TPR ranges from 900-1400 dyn·s·cm⁻⁵ or approximately 11-17 mmHg·min/L in Wood units.

Q2: How does TPR relate to blood pressure?
A: TPR is a major determinant of blood pressure according to the formula: BP = CO × TPR, where BP is blood pressure and CO is cardiac output.

Q3: What factors affect TPR?
A: TPR is influenced by vessel diameter, blood viscosity, vessel length, and autonomic nervous system activity.

Q4: When is TPR measurement clinically important?
A: TPR assessment is crucial in managing hypertension, heart failure, shock states, and during cardiovascular surgical procedures.

Q5: How is TPR measured clinically?
A: TPR is typically calculated during cardiac catheterization using measured pressures and cardiac output derived from thermodilution or Fick methods.