Showing papers by "James B. Skatrud published in 1982"
TL;DR: NREM abolishes between-b Breath augmentations in P100, within-breath load compensation is operant during both AW and NREM (failure of predicted TI prolongation) by differing mechanisms, and arousal may be a ventilatory compensation to inspiratory resistive loading in NREM.
Abstract: Ventilatory and timing responses to repetitive and sustained inspiratory resistive loading were assessed in six naive male subjects during wakefulness (AW) and non-REM sleep (NREM) In five of six subjects, tidal volume (VT) was maintained or increased with repetitive five-breath loading periods during wakefulness In these five subjects, mouth occlusion pressure (P100) increased with loading during AW (18 +/- 05 control vs 22 +/- 04 cmH2O loaded, P less than 005), but not during NREM (21 +/- 15 control vs 21 + 15 cmH2O loaded) For each state, VT and frequency (f) responses to sustained loads were similar to responses to five-breath loads During sustained loading; a) VT increased 35% during AW, decreased 28% during NREM, b) f decreased 35% during AW, increased 6% during NREM, c) minute ventilation (VE) decreased 12% during AW, decreased 23% during NREM Ventilatory responses persisted until arousal (04--17 min) in NREM With repetitive loading: a) inspiratory duration (TI) increased during AW but did not change during NREM, b) “duty cycle” (TI/TT) increased with loading in both states These findings suggest that a) NREM abolishes between-breath augmentations in P100, b) within-breath load compensation is operant during both AW (preserved VT) and NREM (failure of predicted TI prolongation) by differing mechanisms, c) arousal may be a ventilatory compensation to inspiratory resistive loading in NREM
102 citations
TL;DR: It is concluded that the chest-abdominal coordination is related to the underlying pulmonary abnormality, and the paradoxical pattern seen in some patients (Group III) is associated with very severe exercise limitation.
Abstract: The study was undertaken to evaluate the role of coordination between the chest wall and abdomen during exercise in patients with chronic obstructive pulmonary disease (COPD). There were 40 patients with COPD and 6 control subjects with normal lung function who underwent a progressive exercise stress test on a treadmill ergometer. The normal subjects exhibited symmetrical motion between the chest wall and abdomen. Three separate patient groups were differentiated by differences in abdominal response to increasing exercise. Group I was similar to normal or showed an early abdominal peak. Group II had a prolonged outward motion of the abdomen, and Group III had an inward motion of the abdomen during inspiration. Resting pulmonary function (FEV1, VC, DL, RV/TLC) and exercise response (duration, O2 saturation, and maximal VO2) were progressively more abnormal from Group I through Group III. The addition of oxygen to Group III had no effect on the pattern observed. However, when 2 patients with a Group III response were reexercised flexed 45 degrees at the waist they no longer were completely paradoxical, they were less dyspneic, and they could walk farther. It is concluded that the chest-abdominal coordination is related to the underlying pulmonary abnormality, and the paradoxical pattern seen in some patients (Group III) is associated with very severe exercise limitation.
54 citations