THE EFFECTS OF EVA AND LONG-TERM EXPOSURE TO MICROGRAVITY ON
PULMONARY FUNCTION (PUFF)
Research Area: Cardiovascular and Respiratory Systems
Expeditions: 3-6
Principal Investigator(s): ● John B. West, MD, PhD, University of California, San Diego,
La Jolla, California
RESEARCH OBJECTIVES
Various breathing tests are performed before, during, and after flight to see if pulmonary
function is affected by long-term exposure to microgravity or extravehicular activity (EVA or
spacewalks). Changes because of long stays in-orbit, either from removal of gravity itself or
from exposure to contaminants in the closed spacecraft environment, adversely affect crew
health. Changes associated with spacewalks could indicate an increased risk of decompression
sickness, commonly known as the bends.
EARTH BENEFITS
On Earth, many people experience decompression
sickness or “the bends” while diving. This is a result from
the gases (oxygen, nitrogen, and small amounts of other
gases) that are breathed in while diving. The gases are
under pressure, causing not all the oxygen to be
absorbed. Plus, nitrogen produces bubbles in the blood
stream when the body is decompressed. The results
from PuFF may help develop an improved SCUBA system
that can maximize the amount of oxygen absorbed by the
body while diving.
SPACE BENEFITS
There is a large difference in pressure between the inside
of the International Space Station (ISS) and in the
spacesuit used for EVA. The effects of that difference in pressure pose a significant risk of
decompression sickness for spacewalking astronauts (similar to a scuba diver getting the bends)
including bubble formation within the blood. Even if symptoms of decompression sickness do
not occur, venous gas micro bubbles can alter pulmonary function. Noninvasive tests of
pulmonary function that are altered by changes in the pulmonary blood vessels are an ideal
way to follow a subject over the course of multiple EVAs, especially since many EVAs are
required for ISS construction and maintenance. This study also investigates the effects on
pulmonary function of the buildup of particulates or other contaminating gases that can occur
in the closed spacecraft environment. Results from this experiment help to develop
countermeasures for pulmonary problems that occur aboard the ISS, further safeguarding crew
health.
ISS006E07133 – Expedition 6 Flight
Engineer Donald Pettit is performing a
Pulmonary Function in Flight (PuFF) in
the U.S. Laboratory/Destiny. The
purpose is to measure changes in the
evenness of gas exchange in the lungs
and detecting changes in respiratory
muscle strength.