Pulmonary Resistance Calculator


Pulmonary Resistance Calculator

Ever wondered how your lungs are faring in the grand scheme of things? If you’ve ever pondered over a cup of coffee about the resistance offered by your pulmonary arteries, then you’re in the right place! Welcome to the thrilling world of pulmonary resistance calculation! But hold your horses, this isn’t as easy as calculating how many donuts you can eat in one sitting.

The Formula

The formula is as simple as pie (not really!). Here it is:

Pulmonary Resistance = (Pulmonary Artery Pressure - Left Atrial Pressure) / Cardiac Output

Pulmonary Resistance Categories

Here’s a handy table to interpret your pulmonary resistance value:

Category Range (Wood units)
Normal 1 – 2
Mild Pulmonary Hypertension 2 – 3
Moderate Pulmonary Hypertension 3 – 4
Severe Pulmonary Hypertension 4 – 5
Very Severe Pulmonary Hypertension > 5

Calculation Examples

Let’s see how Bob and Nancy fare in their pulmonary resistance calculations:

Person Pulmonary Artery Pressure (mm Hg) Left Atrial Pressure (mm Hg) Cardiac Output (L/min) Calculation Result
Bob, age 40, loves donuts 25 5 5 (25-5)/5 4
Nancy, age 50, hates exercise 30 5 4 (30-5)/4 6.25

Calculation Methods

Here are the different ways to measure pulmonary resistance:

Method Advantage Disadvantage Accuracy
Right heart catheterization Direct measure Invasive High
Echocardiography Non-invasive Less accurate Moderate

Evolution of the Concept

Let’s take a trip down memory lane and see how the concept of measuring pulmonary resistance has evolved:

Year Development
1950s Idea of measuring pulmonary resistance introduced
1970s First invasive methods developed
1990s Non-invasive methods introduced


Every measurement method has its limitations. Here are some for pulmonary resistance:

  1. Inter-individual Variability: Each person’s body responds differently to measurements.
  2. Invasive Techniques: Some methods can be invasive and carry risks.
  3. Accuracy: Non-invasive methods are less accurate than invasive methods.

Alternative Methods

Don’t like the standard methods? Here are some alternatives:

Method Pros Cons
Echocardiography Non-invasive Less accurate
Magnetic Resonance Imaging (MRI) Non-invasive, accurate Expensive


  1. What is pulmonary resistance? Pulmonary resistance refers to the resistance offered by the blood vessels in the lungs to the flow of blood from the heart.
  2. How is pulmonary resistance calculated? Pulmonary Resistance = (Pulmonary Artery Pressure – Left Atrial Pressure) / Cardiac Output.
  3. What is a normal range for pulmonary resistance? The normal range for pulmonary resistance is 1-2 Wood units.
  4. What are Wood units? Wood units are a measure of pressure used in the field of cardiology.
  5. What is pulmonary hypertension? Pulmonary hypertension is a condition characterized by high blood pressure in the arteries leading to the lungs.
  6. How often should I check my pulmonary resistance? This is something you should discuss with your healthcare provider.
  7. What factors can affect pulmonary resistance? Factors such as age, sex, ethnicity, and overall health can affect pulmonary resistance.
  8. Can pulmonary resistance be improved? Certain lifestyle changes and medications can improve pulmonary resistance.
  9. What are the risks of high pulmonary resistance? High pulmonary resistance can lead to conditions such as pulmonary hypertension, which can be serious if left untreated.
  10. Can exercise affect pulmonary resistance? Yes, regular exercise can help lower pulmonary resistance.


  1. National Heart, Lung, and Blood Institute (www.nhlbi.nih.gov): Provides information on pulmonary resistance and related conditions.
  2. American Heart Association (www.heart.org): Provides resources on heart health, including information on pulmonary resistance.