Inspiratory pressure support reduces slowing of inspiratory muscle relaxation rate during exhaustive treadmill walking in severe COPD.

When patients with COPD walk to a state of intolerable dyspnea, there is excessive inspiratory muscle loading, as evidenced by slowing of the maximum relaxation rate of the inspiratory muscles, measured from esophageal pressure during a sniff (Sn Pes MRR). In this setting, inspiratory pressure support (IPS) delivered via an orofacial mask increases walking distance and reduces dyspnea, but the mechanism by which this benefit is achieved remains unclear. In this study we compared Sn Pes MRR after equidistant treadmill walking in six men with severe COPD (mean FEV1: 0.

Effect of L-arginine on renal blood flow in normal subjects and patients with hypoxic chronic obstructive pulmonary disease.

Background: L-arginine is the precursor of endothelium derived nitric oxide (NO) and increasing the available substrate may increase the production of NO. This has been shown by local infusion in peripheral vascular beds but there are few studies of the effects during systemic infusion. Renal vasoconstriction is known to be important in the pathogenesis of cor pulmonale in patients with hypoxic chronic obstructive pulmonary disease (COPD).

Exhaustive exercise slows inspiratory muscle relaxation rate in chronic obstructive pulmonary disease.

The excessive load placed on inspiratory muscles when patients with COPD exercise could lead to fatigue and contribute to exercise limitation. Slowing of maximal relaxation rate (MRR) of skeletal muscle is an early index of the fatiguing process. We investigated whether inspiratory muscle MRR slows when patients with COPD walk to exhaustion.