Archivos de bronconeumología
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Arch. Bronconeumol. · Jan 1996
[Abdominal respiratory muscle activity in patients with stable chronic obstructive pulmonary disease].
With the purpose of defining the pattern of abdominal respiratory muscle activity in patients with chronic obstructive pulmonary disease (COPD), we studied the electromyogram of the rectus abdominis (RA), the external oblique (EO) and transversus (TM) muscles in 14 patients with different degrees of airways obstruction (FEV1: 41 +/- 12%; FEV1/FVC: 45 +/- 10%; RV: 198 +/- 38%; PaO2: 75.8 +/- 12 y PaCO2: 41.4 +/- 5.7 mmHg). The EMG was obtained by insertion of bipolar electrodes guided by an ultrasound image of the abdominal wall to locate the position of the muscles. The measurements were recorded in supine decubitus position in 5 situations: a) breathing at tidal volume; b) slow expiration until RV; c) with inspiratory load; d) with expiratory load, and e) during relaxed breathing with the arms raised. ⋯ The phasic activity pattern recorded when patients were sitting was very similar to that obtained in supine position. In summary, some patients with stable COPD have phasic expiratory activity of the abdominal muscles when resting. These muscles do not appear to act as a unit and this phasic expiratory activity is related to severity of upper airways obstruction.