Pulmonary hypertension diagnosis Swan Ganz catheterization
About this video
This video explains how pulmonary hypertension is diagnosed by threading a Swan-Ganz catheter through the venous system into the right heart and pulmonary artery to measure pressure directly. It compares normal pulmonary pressures, around 8 to 20 mmHg, with the much higher systemic pressures on the left side, and defines the diagnostic threshold as above 25 mmHg.
You'll be able to
- describe how a catheter reaches the pulmonary artery to measure pressure.
- compare normal pulmonary artery pressure with systemic blood pressure.
- state the threshold used to define pulmonary hypertension and why it varies between people.
Key words
- Pulmonary artery
- The vessel that carries blood from the right ventricle to the lungs.
- Pulmonary hypertension
- High blood pressure in the arteries that supply the lungs, diagnosed above 25 mmHg here.
- Swan-Ganz catheter
- A pressure-measuring catheter threaded from a vein through the heart to the pulmonary artery.
- mmHg
- Millimeters of mercury, the unit used to report blood pressure.
- Superior vena cava
- The large vein that carries blood from the upper body into the right atrium.
Transcript
- For diagnosing pulmonary hypertension, we actually can advance a catheter all the way into the area and directly measure the pressure in the pulmonary artery. So really quickly, if we have our heart divided into the four chambers, the right atrium, right ventricle, left atrium, and left ventricle, the pulmonary arteries are plugged right into the right ventricle.
In the anatomical heart, it's actually plugged into the top of the right ventricle and it goes out this way. but I've drawn it here just to show you that it's connected to the right ventricle. So this is our pulmonary artery. The right side of the atrium, the right atrium receives venous blood from the body.
So what we can do is access this whole thing from the veins. What we can do is insert a catheter into a big vein, usually one of the veins in this area, in the arm or up here near the shoulder and neck. Wherever it is, the point is to put this catheter into the vein.
Then under imaging we can advance this catheter along our venous tree. It goes along bigger and bigger veins, finally comes to the superior vena cava. This basically goes right into the right atrium. This catheter is designed specifically to measure pressure. We can see the pressure in the right atrium, in the right ventricle, in the pulmonary artery, and we can even measure the left atrium.
These catheters are named after the people who came up with the technique. So they're called the Swan-Ganz catheters. Their purpose is to measure the pulmonary artery pressure, and/or the pressures in the other chambers. This is basically diagnostic for pulmonary hypertension, because we're just worried about if it crosses the threshold into abnormal.
So for an adult living at sea level, let's be specific, the normal pulmonary artery pressure would be somewhere around 8 to 20. Notice how this is a lot less than the pressures on the systemic side. The left side of our heart has to deal with blood pressure levels, which is 120, 140 in some people.
On the right side, we're pumping into an area that's normally 8 to 20 mmHg. For pulmonary hypertension, technically we define it as a value that's above 25 mmHg as well. But this varies widely according to people. It can change based on altitude. It can change based on your height, a lot of different factors.
But in general, the higher it is, then the more hypertensive we are.
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