Effects of EVA and Long-Term Exposure to Microgravity on Pulmonary Function (PuFF): Results
Results
On
Monday, February 18, 2002, Dan Bursch and Carl Walz, Expedition 4 flight
engineers, performed pre-spacewalk lung-function tests in preparation
for their third EVA on the 20th. That EVA, which was the first EVA conducted
from the Quest airlock without an orbiter present, was recorded by Commander
Yuri Onufrienko using video cameras mounted to the Canadian robotic arm.
The EVA was broadcast live on NASA TV as part of the 40th anniversary
celebration of John Glenn’s Mercury-6 mission as the first U.S. astronaut
to orbit Earth. No other EVAs are planned for the Expedition 4 crew.
On
Thursday, December 27, 2001, Bursch and Walz took computer-based refresher
training on operation of the Puff equipment. The following day, both conducted
their first sessions, which consisted of five lung-function tests. Walz
completed a Puff session on Tuesday, January 15, 2002, after conducting
the first Expedition 4 spacewalk with Onufrienko on Monday. Bursch also
volunteered to perform a session, and the science team were pleased to
receive the additional data. Both participated in additional tests for
the EVA on January 25.
The
Expedition 3 crew conducted two Puff sessions during the week of October
8. They completed one session on Monday, October 8th, before Vladimir
Dezhurov and Mikhail Tyurin conducted spacewalks to continue installation
of the newly-arrived Russian docking compartment, Pirs. A second Puff
session was conducted the next day. For the first time, ground controllers
were able to activate and deactivate the Puff support equipment, saving
the crew a total of 20 minutes work time. With only three crew members
available to conduct all Station operations,
remote operations is an invaluable and necessary tool for completing the
experiments manifested on each mission. Two more Puff sessions were conducted
before and after spacewalk 2, on Monday, October 15, when Dezhurov and
Tyurin attached Russian commercial materials experiments (similar to MISSE)
to the exterior of Pirs.
Results
from previous studies have shown that the lungs are profoundly affected
in space. Gravity causes blood to move primarily through the bottom
portion of the lungs and the weight of the rib cage affects the shape
of the lungs. Without the pull of gravity, the lungs reshape slightly
and blood flows through them differently. Furthermore, chest muscles
that help pump the lungs begin to atrophy in the weightlessness of low
Earth orbit. The ISS crew, who may perform multiple EVAs during
their stay, provide a excellent opportunity to study the cumulative effects
of decompression on the pulmonary system. Additional tests conducted
on the ISS will allow researchers to determine how long-duration space
flight further alters pulmonary function.
Applications
Gravity
tends to distort the lung’s anatomy and exaggerate lung disorders. Removing
the stresses of gravity provides unique insight into lung performance.
Puff will not only provide data that helps researchers understand fundamental
pulmonary physiology, but will also provide data that shows the effects
of decompression and contaminants from closed air systems on lung performance.
Thorough testing under challenging microgravity conditions is the first
step toward developing countermeasures that will protect crews during
long-duration space flight. The countermeasures designed for human
space exploration can also be applied to similar conditions on Earth (variable
air pressure and closed-loop environments), such as on high-altitude aircraft
or submarines.
Related Publications
J.B. West. 2000. Physiology in microgravity. J. Appl. Physiol. 89: 379-384.
J.B. West and G.K. Prisk. 1999. Chest volume and shape and intrapleural pressure in microgravity [letter]. J. Appl. Physiol. 87: 1240.
G.K. Prisk, H.J. Guy, A.R. Elliott, and J.B. West. 1994. Cardiopulmonary adaptation to weightlessness. J Gravit Physiol. 1(1):P118-21. [Abstract]
J.B. West. 1993. Acclimatization and tolerance to extreme altitude. J Wilderness Med. 4(1):17-26. [Abstract]
