Calculator
Formula Used
MAP from blood pressure:
MAP = (SBP + 2 × DBP) ÷ 3
Pressure gradient:
Pressure Gradient = MAP − CVP
Total peripheral resistance:
TPR = (MAP − CVP) ÷ Cardiac Output
Systemic vascular resistance conversion:
SVR = TPR × 80
Indexed resistance:
SVRI = SVR × BSA
Estimated cardiac output:
Cardiac Output = Heart Rate × Stroke Volume ÷ 1000
How to Use This Calculator
- Enter a case label for your record.
- Select whether MAP should be estimated or entered directly.
- Enter SBP and DBP, or enter direct MAP.
- Enter central venous pressure.
- Choose direct cardiac output or estimate it from HR and stroke volume.
- Enter body surface area if indexed resistance is needed.
- Select decimal places for rounded results.
- Press the calculate button.
- Review the result above the form.
- Download the CSV or PDF file when needed.
Example Data Table
| Example | MAP | CVP | CO | TPR | SVR | Comment |
|---|---|---|---|---|---|---|
| Resting teaching case | 93 mmHg | 3 mmHg | 6.5 L/min | 13.85 mmHg·min/L | 1107.69 dyn·s/cm5 | Common teaching range |
| Low resistance case | 80 mmHg | 5 mmHg | 8 L/min | 9.38 mmHg·min/L | 750 dyn·s/cm5 | Lower range |
| High resistance case | 110 mmHg | 5 mmHg | 4 L/min | 26.25 mmHg·min/L | 2100 dyn·s/cm5 | Higher range |
Understanding Total Peripheral Resistance
Total peripheral resistance describes the opposition to blood flow through the vascular network. The idea is close to an electrical circuit. Pressure difference acts like voltage. Flow acts like current. Resistance links both values. This calculator uses that analogy, while keeping medical units clear. It is useful for physiology lessons, lab reports, and hemodynamic reviews.
Why The Calculation Matters
A higher resistance value can mean the circuit is tighter. A lower value can mean flow meets less opposition. The result depends on mean arterial pressure, central venous pressure, and cardiac output. Small changes in any input can shift the final value. That is why the form shows pressure drop, cardiac output source, indexed value, and conductance. These extra outputs help users review the result instead of reading one number only.
Electrical Analogy
Ohm’s law says resistance equals voltage divided by current. Hemodynamics uses a similar structure. The pressure gradient is MAP minus CVP. Cardiac output is the flow term. Dividing the gradient by flow gives peripheral resistance units. Multiplying by 80 converts the value into dyn·s/cm5. This unit is often used for systemic vascular resistance. When body surface area is entered, the tool also reports an indexed value.
Practical Input Notes
Use measured values when available. If cardiac output is not known, the calculator can estimate it from heart rate and stroke volume. That estimate is only as strong as the supplied data. Use consistent units. Press calculate after entering the values. The result appears above the form. Then use the export buttons to download a CSV or PDF record.
Advanced Review Options
The calculator also reports conductance. Conductance is the inverse of resistance. It can help compare cases with different pressure gradients. The interpretation label is a simple teaching guide. It uses broad ranges only. Rounding control lets you match classroom precision. A case label can make exports easier to sort later.
Safe Use
This page is for education and calculation support. It should not diagnose disease. Clinical interpretation needs trained review and full patient context. Always compare results with local protocols and validated instruments. Recheck unusual values before saving them. Mistyped pressures or flow values can create misleading resistance levels quickly during final review.
FAQs
What is total peripheral resistance?
Total peripheral resistance is the calculated opposition to flow in the vascular system. It uses pressure difference and cardiac output. The calculator presents it with related converted values.
Why is this listed under electrical calculation?
The calculation follows an electrical analogy. Pressure difference behaves like voltage. Cardiac output behaves like current. Resistance links both values in a similar way.
Which MAP method should I choose?
Use direct MAP when you already have a measured mean pressure. Use SBP and DBP when only routine blood pressure values are available.
Can the calculator estimate cardiac output?
Yes. Select the estimated option. Then enter heart rate and stroke volume. The tool multiplies both values and converts milliliters to liters.
What does SVR mean?
SVR means systemic vascular resistance. It is the converted form of total peripheral resistance. The calculator multiplies TPR by 80 to show dyn·s/cm5.
What is indexed resistance?
Indexed resistance adjusts SVR by body surface area. Enter BSA to calculate SVRI. Leave it blank when indexing is not needed.
Is this calculator for diagnosis?
No. It is for education, reports, and calculation review. Medical decisions need professional assessment, patient history, measurements, and local clinical protocols.
Why are CSV and PDF downloads useful?
CSV helps with spreadsheets and datasets. PDF helps with printed reports. Both options save the calculated values for later review.