The Effect of Adding Noninvasive Ventilation to High-Intensity Exercise on Peripheral and Respiratory Muscle Oxygenation.

BACKGROUND: We sought to assess whether noninvasive ventilation (NIV) as an adjunct with high-intensity exercise (HIEx) is more effective than exercise alone or exercise + sham on respiratory and peripheral oxygenation and vascular function in subjects with coexisting COPD and heart failure (HF). METHODS: On separate days, subjects performed incremental cardiopulmonary exercise testing and 3 constant load tests: HIEx, HIEx+NIV, and HIEx+sham (bi-level mode, Astral 150). Subjects were randomized with a 1:1 block allocation for the HIEx+NIV group and HIEx+sham group until the limit of tolerance (Tlim). Peripheral and respiratory oxygenation were assessed by oxyhemoglobin (O2Hb) and deoxyhemoglobin (Hb) using near-infrared spectroscopy in the respiratory and peripheral musculature. Vascular function was assessed by endothelial function using the flow-mediated vasodilation (FMD) method. RESULTS: There was a significant increase in FMD (mm), FMD (%), and shear stress in the HIEx+NIV group when compared to HIEx or HIEx+sham (P < .05). Less extraction of O2 (Hb) in the peripheral and respiratory muscles was observed in the HIEx+NIV group (P < .05). We also found correlations between peripheral muscle oxygenation (O2Hb) at the moment 80% of Tlim (r = 0.71, P = .009) and peak of Tlim (100%) (r = 0.76, P = .004) with absolute FMD (mm) immediately after HIEx+NIV. CONCLUSIONS: NIV as an adjunct to HIEx can acutely unload the respiratory musculature with better redistribution of available blood flow and beneficially modulate endothelial function. These results may influence the approach to cardiopulmonary rehabilitation in patients with coexisting COPD-HF.

Non-invasive ventilation improves exercise tolerance and peripheral vascular function after high-intensity exercise in COPD-HF patients.

AIM: Evaluate the acute effects of non-invasive positive pressure ventilation (NiPPV) during high-intensity exercise on endothelial function in patients with coexisting chronic obstructive pulmonary disease (COPD) and heart failure (HF). METHODS: This is a randomized, double blinded, sham-controlled study involving 14 COPD-HF patients, who underwent a lung function test and Doppler echocardiography. On two different days, patients performed incremental cardiopulmonary exercise testing (CPET) and two constant-work rate tests (80% of CPET peak) receiving Sham or NiPPV (bilevel mode - Astral 150) in a random order until the limit of tolerance (Tlim). Endothelial function was evaluated by flow mediated vasodilation (FMD) at three time points: 1) Baseline; 2) immediately post-exercise with NiPPV; and 3) immediately post-exercise with Sham. RESULTS: Our patients had a mean age of 70 ± 7 years, FEV1 1.9 ± 0.7 L and LVEF 41 ± 9%. NIPPV resulted in an increased Tlim (NiPPV: 130 ± 29s vs Sham: 98 ± 29s p = 0.015) and SpO2 (NiPPV: 94.7 ± 3.5% vs Sham: 92.7 ± 5.2% p = 0.03). Also, NiPPV was able to produce a significant increase in FMD (%) (NiPPV: 9.2 ± 3.1 vs Sham: 3.6 ± 0.7, p < 0.05), FMD (mm) (NiPPV: 0.41 ± 0.18 vs Sham: 0.20 ± 0.11, p < 0.05), Blood flow velocity (NiPPV: 33 ± 18 vs Baseline: 20 ± 14, p < 0.05) and Shear Stress (SS) (NiPPV: 72 ± 38 vs Baseline: 43 ± 25, p < 0.05). We found correlation between Tlim vs. ΔSS (p = 0.03; r = 0.57). Univariate-regression analysis revealed that increased SS influenced 32% of Tlim during exercise with NiPPV. CONCLUSION: NiPPV applied during high-intensity exercise can acutely modulate endothelial function and improve exercise tolerance in COPD-HF patients. In addition, the increase of SS positively influences exercise tolerance.