Functional condition of efferent part of respiratory neuromotor system in patients with chronic obstructive pulmonary diseases

Abstract

The functional condition of efferent part of respiratory neuromotor system (RNS) was examined in 67 patients with chronic obstructive pulmonary diseases (COPD) using transcerebral and transspinal magnetic stimulation of diaphragm. The research resultes demonstrated that in spite of the absence of clinical features of respiratory muscles failure (RMF) in 28 COPD patients the maximal transdiaphragmic pressure (P_{di max}) was decreased, cerebral and spinal response amplitudes were reduced (0.74±0.43 mV; p<0.05 and 0.8±0.43 mV; p < 0.05 respectively) under the reliable prolongation of latent time of the spinal motor response (6.4±0.35 ms; p<0.01). Thirty six patients with RMF showed the increased latention of the cerebral and spinal motor responses (17.5±0.9 and 7.9±0.42 ms; p<0.01) against the background of the apparent drop in their amplitudes (0.44±0.039 and 0.51±0.004 mV; p<0.01 in both the cases). Furthermore, the central conduction time was increased by 12.3±1.1% (p<0.05) in 8 (23%) patients with RMF. The study results demonstrated the central and peripheral disturbances of the efferent part of RNS in COPD patients.