Sk. Epstein et al., VENTILATORY RESPONSE TO ARM ELEVATION - ITS DETERMINANTS AND USE IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE, American journal of respiratory and critical care medicine, 152(1), 1995, pp. 211-216
Citations number
33
Categorie Soggetti
Emergency Medicine & Critical Care","Respiratory System
During arm elevation, normal individuals predominantly recruit the dia
phragm, whereas chronic obstructive pulmonary disease (COPD) patients
use more the accessory inspiratory and abdominal expiratory muscles. T
o test that arm elevation is useful to study the ventilatory muscle re
sponse in COPD, and to define the factors that determine this response
, we studied 34 patients (FEV(1) 0.95 +/- 0.08 L) during 2 min of arm
elevation. Transnasal balloons were used to determine end-inspiratory
and endexpiratory gastric (Pg), pleural (Ppl) and transdiaphragmatic (
Pdi) pressures. The slope of Delta Pg/Delta Ppl (= Pg(i) - Pg(e)/Ppl(i
) - Ppl(e)) was used to infer respiratory muscle recruitment. With lin
ear regression, the Delta Pg/Delta Ppl during arm elevation significan
tly correlated with resting Delta Pg/Delta Ppl (r = 0.68), hyperinflat
ion (FRC/TLC, r = 0.52), and diaphragmatic tension time index (TTldi)
(r = 0.47). With multiple regression, resting Delta Pg/Delta Ppl, perc
entage predicted FRC (FRC %pred) and TTldi influenced Delta Pg/Delta P
pl during arm elevation (r = 0.84). Over the 2 min of arm elevation, t
he dependency upon resting breathing pattern decreased, while hyperinf
lation and TTldi became increasingly important. Higher resting TTldi v
alues were associated with a faster and shallower breathing pattern (f
/V-T greater than or equal to 38) during arm elevation. We conclude th
at the pattern of respiratory muscle recruitment during arm elevation
depends primarily on the resting breathing pattern. Over 2 min, the de
gree of hyperinflation and the force reserve of the diaphragm increasi
ngly impact on the ability to recruit the diaphragm. Measurement of f/
V-T during arm elevation is useful to determine functional reserve of
the diaphragm in severe COPD.