Non-invasive ventilatory support accelerates the oxygen uptake and heart rate kinetics and improves muscle oxygenation dynamics in COPD-HF patients.

BACKGROUND: The aim of this study was to explore the effects of non-invasive positive pressure ventilation (NIPPV) associated with high-intensity exercise on heart rate (HR) and oxygen uptake (V̇O2) recovery kinetics in in patients with coexistence of chronic obstructive pulmonary disease (COPD) and heart failure (HF). METHODS: This is a randomized, double blinded, sham-controlled study involving 14 HF-COPD 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). During exercise, oxyhemoglobin and deoxyhemoglobin were assessed using near-infrared spectroscopy (Oxymon, Artinis Medical Systems, Einsteinweg, Netherland). RESULTS: The kinetic variables of both V̇O2 and HR during the high-intensity constant workload protocol were significantly faster in the NIPPV protocol compared to Sham ventilation (P < 0.05). Also, there was a marked improvement in oxygenation and lower deoxygenation of both peripheral and respiratory musculature in TLim during NIPPV when contrasted with Sham ventilation. CONCLUSIONS: NIPPV applied during high-intensity dynamic exercise can effectively improve exercise tolerance, accelerate HR and V̇O2 kinetics, improve respiratory and peripheral muscle oxygenation in COPD-HF patients. These beneficial results from the effects of NIPPV may provide evidence and a basis for high-intensity physical training for these patients in cardiopulmonary rehabilitation programs.

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.

Effect of high-intensity exercise on cerebral, respiratory and peripheral muscle oxygenation of HF and COPD-HF patients.

OBJECTIVE: To investigate cerebral oxygenation (Cox) responses as well as respiratory (Res) and active peripheral muscle (Pm) O2 delivery during high-intensity cycling exercise and contrast responses between patients with coexistent chronic obstructive pulmonary disease (COPD)-heart failure (HF) and HF alone. METHODS: Cross-sectional study involving 11 COPD-HF and 11 HF patients. On two different days, patients performed maximal incremental cardiopulmonary exercise testing (CPET) and constant load exercise on a cycle ergometer until the limit of tolerance (Tlim). The high-intensity exercise session was 80% of the peak CPET work rate. Relative blood concentrations of oxyhemoglobin ([O2Hb]), deoxyhemoglobin ([HHb]) of Res, Pm (right vastus lateralis) and Cox (pre-frontal) were measured using near infrared spectroscopy. RESULTS: We observed a greater decrease in [O2Hb] at a lower Tlim in COPD-HF when compared to HF (P < 0.05). [HHb] of Res was higher (P < 0.05) and Tlim was lower in COPD-HF vs. HF. Pm and Cox were lower and Tlim was higher in (P < 0.05) HF vs. COPD-HF. In HF, there was a lower ∆[O2Hb] and higher ∆ [HHb] of Pm when contrasted to Cox observed during exercise, as well as a lower ∆ [O2Hb] and higher ∆ [HHb] of Res when contrasted with Cox (P < 0.05). However, COPD-HF patients presented with a higher ∆ [HHb] of Res and Pm when contrasted with Cox (P < 0.05). CONCLUSION: The coexistence of COPD in patients with HF produces negative effects on Cox, greater deoxygenation of the respiratory and peripheral muscles and higher exertional dyspnea, which may help to explain an even lower exercise tolerance in this multimorbidity phenotype.

Linear and nonlinear analysis of heart rate variability in coronary disease.

OBJECTIVE: Coronary artery disease (CAD) and acute myocardial infarction (AMI) are associated with a reduction of heart rate variability (HRV). The aim of this study was to compare the HRV of CAD patients with and without AMI (CAD-AMI) with health-matched controls by linear (spectral analysis) and nonlinear [Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA)] analysis. METHODS: Fifty-eight men were divided into three groups: healthy (n = 19, 57 ± 4 years), CAD (n = 20, 56 ± 10 years) and CAD-AMI (n = 19, 54 ± 12 years). The RR intervals were recorded at rest in the supine position for 10 min with an HR monitor (Polar(®)S810i). A series of 250 beats was selected to analyze variance, spectral analysis, SE, CE [complexity index (CI), normalized CI (NCI)] and SA (0V, 1V, 2LV and 2ULV patterns), as well as 0V (no significant variation) and 2ULV (two significant unlike variations), which reflect sympathetic and vagal modulation, respectively. One-way ANOVA (or the Kruskal-Wallis test when appropriate) and Pearson correlation were used. RESULTS: The CAD group had higher body mass index and weight than the CAD-AMI group, but no differences were found between the healthy and AMI groups. There were no differences between the groups regarding linear and nonlinear analysis. The 0V and 2ULV patterns were significantly correlated with the SE, CI and NCI of the three groups. INTERPRETATION: There was no difference between the groups regarding cardiac autonomic modulation by linear and nonlinear methods, which may be due to beta-blocker use, coronary angioplasty and the exercise capacity of healthy subjects.