Chest, Vol 99, 1186-1192, Copyright © 1991 by American College of Chest Physicians

ARTICLES

Suppression of ventilatory muscle activity in healthy subjects and COPD patients with negative pressure ventilation

F Gigliotti, R Duranti, A Fabiani, M Schiavina and G Scano
Istituto di Clinica Medica III, Universita degli Studi, Florence, Italy.

We evaluated the ability of NPV to suppress EMGd and EMGint in seven patients with severe COPD and five normal subjects. Subjects were studied either without (A) or with mouthpiece and nose clip (B). Electromyographic suppression was assessed comparing EMG activity during NPV with the control activity without a mouthpiece and prior to the initiation of the NPV run. In normal subjects, in A, NPV resulted in a partial suppression of EMGd; in B, prior to NPV, EMGd rose compared with A prior to NPV. In patients, in A, NPV resulted in a suppression of both EMGd and EMGint. In B, prior to NPV, both EMGd and EMGint rose compared with A prior to NPV. Thus, it seems that NPV is able to produce a consistent reduction in inspiratory muscle EMG activity. This variable NPV ability would have to be assessed for better selection criteria for patient candidates in a rehabilitation program.