Pulmonary artery pressure at altitude

It has been known for a long time that the pulmonary artery pressure (pressure in the arteries of lung) goes up when one goes to high altitude. If supplemental oxygen is given, the pulmonary artery pressure drops back to normal, but after being at altitude for months or years, a short burst of oxygen (say 30 minutes) does not reduce the pressure back to normal. We would like to see what happens during the first few days here at the Margherita Hut.

We can measure the pulmonary artery pressure (PAP) using echocardiography, a non-invasive technique ? a challenging task for Edith, who is performing the tests. We performed baseline studies in London breathing air and then gas with a low concentration of oxygen. Here at the Hut, we make measurements each day on all of our subjects. First we measure the PAP with the subjects breathing air, followed by 30 minutes of high oxygen concentration which is equivalent to that at sea level.

We expected that on the first day the oxygen would bring the PAP back to sea level values but that after some days at altitude the effect of oxygen might decline or even have no effect at all. Of course life is seldom that simple. Different subjects respond differently and we hope that by the end of our stay here we might see some pattern emerging.

Jim Milledge and Edith Kortekaas

Story by Ali Cobb