Acute effect of oxygen therapy on exercise tolerance and dyspnea perception in ILD patients.

Ambulatory oxygen therapy (AOT) is commonly prescribed in interstitial lung disease (ILD) patients, with the aim of reducing dyspnea and increasing exercise tolerance. Despite its frequent use and a reasonable physiological rationale, there is a lack of evidence supporting the effect of AOT on improving dyspnea during exercise. Moreover, dyspnea encompasses distinct sensory (intensity, quality) and affective (anxiety, fear) components with different underlying neurophysiological mechanisms. The aim of this study was to evaluate the effect of oxygen supplementation on exercise tolerance and dyspnea in ILD patients with exercise induced hypoxia (EIH). Forty-seven ILD patients performed a six-minute walk test (6MWT) on room air (RA) and with oxygen supplementation (Ox). The 6MWT distance (6MWD) was significantly greater with oxygen supplementation (RA: 242±143 m vs Ox: 345±106 m p<0,01). With oxygen supplementation, the overall dyspnea and anxiety significantly decreased both at rest [1.1±1.4 Borg Unit (BU)] vs 0.4±0.9BU, p.<0.01, and 1.1±1.6BU vs 0.5±1.3 BU, p.<0.05, respectively) and at the end of exercise (5.1±2.6 BU vs 3.7±2.5 BU, p<0.001 and 3.4 ±2.9 vs 2.5±2.8, p.<0.01, respectively) despite a greater walked distance. In ILD patients with EIH, oxygen supplementation increases the exercise tolerance and reduces overall dyspnea perception and the anxiety component of breathlessness.

The impact of long-acting muscarinic antagonists on mucus hypersecretion and cough in chronic obstructive pulmonary disease: a systematic review.

Patients suffering from chronic obstructive pulmonary disease (COPD) clinically manifest airway mucus hypersecretion as sputum expectoration and cough. Evidence accumulated in the past decade has shown that the cholinergic system not only regulates airway smooth muscle contraction but also the activity of inflammatory and airway epithelial cells, including goblet cells, and submucosal gland activity. Long-acting muscarinic antagonists (LAMAs) with the most favourable M3/M2 muscarinic acetylcholine (ACh) receptors residency properties are not only excellent bronchodilators but potentially also mucus-modifying agents, able to positively impact on mucus hypersecretion and cough. The aim of this systematic review was to investigate the impact of LAMAs on mucus hypersecretion and cough in COPD patients. The evidence confirmed that LAMAs, mainly tiotropium and aclidinium, improved sputum production and cough in moderate to severe COPD. Thus, LAMAs not only antagonise the ACh-induced bronchoconstriction of the airways but also appear to limit the production of mucus secreted in response to ACh by airway goblet cells and/or submucosal glands. Further clinical studies are necessary to evaluate the impact of LAMAs exclusively on sputum symptoms and cough as primary end-points and to investigate whether LAMAs have a modulatory action on the rheological properties of mucus.