The cardiopulmonary effects of an inelastic chest wall restriction
File(s)
Date
2000-08Author
Miller, Jordan
Advisor(s)
Triplett-McBride, T.
Metadata
Show full item recordAbstract
We examined the effects of an inelastic chest wall restriction (CWR) on
cardiopulmonaxy function during rest and exercise in an attempt to mimic a condition
similar to that seen in chronic heart failure. Forced vital capacities were measured at the
beginning of the study, after which point four canvas straps were applied tightly around
the thorax and abdomen so that vital capacity was reduced by >35%. Data were acquired
during resting, 25%. and 45% of the peak workload achieved during the subjects'
screening visit. Vital capacity, total lung capacity, and residual volume were all
significantly reduced during CWR conditions. Subjects exhibited significant increases in
ventilation brought about by increases in breathing frequency, despite decreases in tidal
volume. This breathing pattern elicited significant increases in the flow resistive work of
breathing and the gastric pressure-time integral (>400%), and resulted in a decrease in the
elastic work of breathing. Significant decreases in cardiac output (>lo%) during CWR
conditions were brought about by decreases in stroke volume. Heart rate, blood pressure,
and calculated a-v& difference were all significantly elevated during CWR exercise
conditions. We conclude that CWR conditions significantly affect pulmonary and
cardiovascular function, although the mechanisms causing the decrease in cardiac output
during CWR exercise conditions remain unclear. Additionally, our data suggest that
CWR conditions elicit breathing patterns and cardiac responses similar to those seen in
chronic heart failure, implying that CWR may be used as a crude model to study CIS.