EFFECTS OF RESISTIVE LOADING ON THE PATTERN OF BREATHING

In order to determine changes in breathing patterns brought about by r esistive loading, ventilation was recorded in 11 healthy subjects with four linear resistances (3.57, 5.75, 8.76 and 13.13 cmH(2)O L-1 sec) added in a random order throughout the entire breath. At steady state: a breath-by-breath analysis of airflow was used to quantify the patte rn of breathing in terms of respiratory variables: TI, TE, Tt, VT, VT/ TI, TI/Tt, and by taking TI, TE, VT all together (TRIAD) and also the shape of the entire airflow profile quantified by harmonic analysis (A STER). Group analysis using ANOVA showed significant changes in all va riables. There were increasing changes with increasing loads in all va riables, the smallest changes being in TI/Tt. Within to between-indivi dual comparisons between two loads showed that only TI/Tt and the ASTE R were more similar within than between-individuals for all comparison s. It was concluded that at steady state mechanisms of load compensati on come into play inducing changes in the pattern of breathing proport ional to the loads while maintaining some of the individual characteri stics. (C) 1998 Elsevier Science B.V. All rights reserved.