Can Non-invasive Ventilation Modulate Cerebral, Respiratory, and Peripheral Muscle Oxygenation During High-Intensity Exercise in Patients With COPD-HF?

AIM: To evaluate the effect of non-invasive positive pressure ventilation (NIPPV) on (1) metabolic, ventilatory, and hemodynamic responses; and (2) cerebral (Cox), respiratory, and peripheral oxygenation when compared with SHAM ventilation during the high-intensity exercise in patients with coexisting chronic obstructive pulmonary disease (COPD) and heart failure (HF). METHODS AND RESULTS: On separate days, patients performed incremental cardiopulmonary exercise testing and two constant-work rate tests receiving NIPPV or controlled ventilation (SHAM) (the bilevel mode-Astral 150) in random order until the limit of tolerance (Tlim). During exercise, oxyhemoglobin (OxyHb+Mb) and deoxyhemoglobin (DeoxyHb+Mb) were assessed using near-infrared spectroscopy (Oxymon, Artinis Medical Systems, Einsteinweg, The Netherlands). NIPPV associated with high-intensity exercise caused a significant increase in exercise tolerance, peak oxygen consumption ( V · O 2 in mlO2·kg-1·min-1), minute ventilation peak ( V · E in ml/min), peak peripheral oxygen saturation (SpO2, %), and lactate/tlim (mmol/s) when compared with SHAM ventilation. In cerebral, respiratory, and peripheral muscles, NIPPV resulted in a lower drop in OxyHb+Mb (p < 0.05) and an improved deoxygenation response DeoxyHb+Mb (p < 0.05) from the half of the test (60% of Tlim) when compared with SHAM ventilation. CONCLUSION: Non-invasive positive pressure ventilation during constant work-rate exercise led to providing the respiratory muscle unloading with greater oxygen supply to the peripheral muscles, reducing muscle fatigue, and sustaining longer exercise time in patients with COPD-HF.

Reliability of Cardiorespiratory and Metabolic Responses During Incremental Shuttle Walk Test in Adult Subjects With Asthma.

BACKGROUND: The incremental shuttle walk test (ISWT) has been widely used to assess exercise capacity of subjects with COPD. However, to date, no studies have assessed its reliability in the asthmatic population. This study aimed to assess the test-retest reliability of ISWT for the distance walked (ISWD) and cardiorespiratory and metabolic responses in adult subjects with asthma. METHODS: This was a cross-sectional observational study. Thirty-four subjects of both genders, 18-45 y old, with a diagnosis of controlled asthma, were recruited from March 2012 to December 2015. The subjects performed 3 ISWTs on different days, with a minimum interval of 48 h and a maximum of 1 week between the second and third ISWT. For the reliability analysis, the values of the second and third ISWTs were used, eliminating the influence of any learning effect from the first test. RESULTS: The intraclass correlation coefficients were > 0.75 (P < .001) for ISWD (m), speed (km/h),oxygen uptake (V̇O2 ), ventilatory equivalent carbon dioxide (V̇E/V̇CO2 ), and minute ventilation (V̇E) at the ISWT peak. The Bland-Altman plot presented a mean error close to zero, and measurement distribution was within acceptable limits of variation. CONCLUSION: The ISWT presented excellent reliability for the ISWD and metabolic responses. The cardiorespiratory responses in the ISWTs presented good reliability. We concluded that the ISWT was reliable for young adult subjects with controlled asthma.