Effect of Ambulatory Oxygen on the Respiratory Pattern during the 6 Min Walking Test in Patients with Interstitial Lung Diseases

Introduction: Patients with pulmonary fibrosis experience early oxyhemoglobin desaturation under effort, which limits their ability to exercise and quality of life. Recent studies have shown that in resting normoxaemic patients who become hypoxemic exertion, administration outpatient oxygen significantly improves stress dyspnoea It is unclear how this happens, since does not act directly on dyspnoea, appear much effect the heart rate artery pressure. We tested hypothesis correcting hypoxaemia could reduce increase respiratory effort during 6 min walking test, recording breathing pattern or placebo. Methods: evaluated 20 fibrotic interstitial lung diseases (17 males 3 females; mean age 72 ± 2 years; M SE) a SpO2 ≥92 fell ≤88% walk test (6MWT). After first establishing flow necessary prevent desaturation, underwent two further 6MWT, 15–20 apart, one medical air at same flow, randomized double-blind order. During SpO2, rate, tidal volume minute ventilation (VE) were recorded, using Spiropalm spirometer (Cosmed, Rome, Italy). Results: Oxygen saturation 6MWT decreased minimum value 82.3% (95% CI 80.1–84.5%) placebo 92% (90.3–93.7%) an average difference 9.7% (7.8–11.6%, p < 0.0001). On contrary, showed increasing trend time reaching higher maximum placebo, 5.4 bpm (2.9–8.7, 0.005) compared oxygen. The distance walked was slightly but greater after by 28 m (2–53, 0.05) end 0.6 points (0.1–1.1, 0.05). Respiratory increased over time, without differences between walking, then more (p 0.0005). With rapidly plateau about 48% FVC min, while oxygen, slower, 45% test. Nevertheless, highly significant 0.0005) all points. Minute also remained lower level than Mean reduction VE 4.4 L/min (3.9–4.9, Conclusion: In our ILD patients, related reduced meet requirements, resulting workload cardiovascular system muscles consequent dyspnoea.