Am. J. Respir. Crit. Care Med., Vol 151, No. 2, Feb 1995, 399-405.
Normal thoracoabdominal motions. Influence of sex, age, posture, and breath size
JA Verschakelen and MG Demedts
Laboratory of Pneumology, University of Leuven, Belgium.
The purpose of this study was to assess normal values of thoracoabdominal
motions (TAM) during spontaneous breathing and vital capacity (VC)
maneuvers in relation to sex, age, and body position. For this, 120 healthy
subjects from 10 to > 60 yr old were studied using the respiratory
inductive plethysmograph (Respitrace). The volume- motion coefficients
obtained during quiet breathing for the rib cage (RC) were almost twice
those for the abdomen (ABD) and were not influenced by sex or age and also
not by posture, except for the increased ABD coefficients in the supine
posture (p < 0.05). Under most conditions RC motion predominated over
ABD motion, except quiet breathing in the supine position. Sex-related
differences in TAM were not found during quiet breathing, yet during VC
maneuvers the women were slightly more RC breathing (p < 0.01).
Age-related differences were also only significant during VC maneuvers: men
of more than 50 yr old especially became less RC breathing. Posture had a
very significant effect (p < 0.001) during quiet breathing as well as
during VC maneuvers: the RC predominance was greatest in the standing
posture and least in the supine posture. During VC maneuvers the subjects
became more RC breathers than during quiet breathing (p < 0.001). The
X-Y coordinates of RC motion (on the Y axis) versus ABD motion (on the X
axis) showed under all conditions a counterclockwise looping during the
breathing cycle: the looping was elliptic during quiet breathing but was
more irregular and variable during VC maneuvers, and this also depended on
body position.(ABSTRACT TRUNCATED AT 250 WORDS)
