Comparable Ventilatory Inefficiency at Maximal and Submaximal Performance in COPD vs. CHF subjects: An Innovative Approach. / Ineficiência Ventilatória Comparável no Desempenho Máximo e Submáximo em Indivíduos com DPOC e ICC: Uma Abordagem Inovadora.

BACKGROUND: Currently, excess ventilation has been grounded under the relationship between minute-ventilation/carbon dioxide output ( V ˙ E - V ˙ CO 2 ). Alternatively, a new approach for ventilatory efficiency ( η E V ˙ ) has been published. OBJECTIVE: Our main hypothesis is that comparatively low levels of η E V ˙ between chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) are attainable for a similar level of maximum and submaximal aerobic performance, conversely to long-established methods ( V ˙ E - V ˙ CO 2 slope and intercept). METHODS: Both groups performed lung function tests, echocardiography, and cardiopulmonary exercise testing. The significance level adopted in the statistical analysis was 5%. Thus, nineteen COPD and nineteen CHF-eligible subjects completed the study. With the aim of contrasting full values of V ˙ E - V ˙ CO 2 and η V ˙ E for the exercise period (100%), correlations were made with smaller fractions, such as 90% and 75% of the maximum values. RESULTS: The two groups attained matched characteristics for age (62±6 vs. 59±9 yrs, p>.05), sex (10/9 vs. 14/5, p>0.05), BMI (26±4 vs. 27±3 Kg m2, p>0.05), and peak V ˙ O 2 (72±19 vs. 74±20 %pred, p>0.05), respectively. The V ˙ E - V ˙ CO 2 slope and intercept were significantly different for COPD and CHF (27.2±1.4 vs. 33.1±5.7 and 5.3±1.9 vs. 1.7±3.6, p<0.05 for both), but η V ˙ E average values were similar between-groups (10.2±3.4 vs. 10.9±2.3%, p=0.462). The correlations between 100% of the exercise period with 90% and 75% of it were stronger for η V ˙ E (r>0.850 for both). CONCLUSION: The η V ˙ E is a valuable method for comparison between cardiopulmonary diseases, with so far distinct physiopathological mechanisms, including ventilatory constraints in COPD.

FUNDAMENTO: Atualmente, o excesso de ventilação tem sido fundamentado na relação entre ventilação-minuto/produção de dióxido de carbono ( V ˙ E − V ˙ CO 2 ). Alternativamente, uma nova abordagem para eficiência ventilatória ( η E V ˙ ) tem sido publicada. OBJETIVO: Nossa hipótese principal é que níveis comparativamente baixos de η E V ˙ entre insuficiência cardíaca crônica (ICC) e doença pulmonar obstrutiva crônica (DPOC) são atingíveis para um nível semelhante de desempenho aeróbico máximo e submáximo, inversamente aos métodos estabelecidos há muito tempo (inclinação V ˙ E − V ˙ CO 2 e intercepto). MÉTODOS: Ambos os grupos realizaram testes de função pulmonar, ecocardiografia e teste de exercício cardiopulmonar. O nível de significância adotada na análise estatística foi 5%. Assim, dezenove indivíduos elegíveis para DPOC e dezenove indivíduos elegíveis para ICC completaram o estudo. Com o objetivo de contrastar valores completos de V ˙ E − V ˙ CO 2 e η E V ˙ para o período de exercício (100%), correlações foram feitas com frações menores, como 90% e 75% dos valores máximos. RESULTADOS: Os dois grupos tiveram características correspondentes para a idade (62±6 vs 59±9 anos, p>.05), sexo (10/9 vs 14/5, p>0,05), IMC (26±4 vs 27±3 Kg m2, p>0,05), e pico V ˙ O 2 (72±19 vs 74±20 % pred, p>0,05), respectivamente. A inclinação V ˙ E − V ˙ CO 2 e intercepto foram significativamente diferentes para DPOC e ICC (207,2±1,4 vs 33,1±5,7 e 5,3±1,9 vs 1,7±3,6, p<0,05 para ambas), mas os valores médios da η E V ˙ foram semelhantes entre os grupos (10,2±3,4 vs 10,9±2,3%, p=0,462). As correlações entre 100% do período do exercício com 90% e 75% dele foram mais fortes para η E V ˙ (r>0,850 para ambos). CONCLUSÃO: A η E V ˙ é um método valioso para comparação entre doenças cardiopulmonares, com mecanismos fisiopatológicos até agora distintos, incluindo restrições ventilatórias na DPOC.

Diaphragm thickness and mobility elicited by two different modalities of inspiratory muscle loading in heart failure participants: A randomized crossover study.

OBJECTIVES: To analyze diaphragmatic thickness, at end-inspiration and end-expiration, diaphragmatic thickening index and mobility via US under two different modalities of inspiratory muscle loading, in two different modalities of inspiratory muscle loading and different load intensities at full-vital capacity maneuvers and the relationship between diaphragmatic thickness with pulmonary function tests in participants with HF. METHODS: This randomized crossover trial, enrolled with 17 HF subjects, evaluated diaphragm thickness (Tdi, mm), fractional thickness (TFdi, %), and mobility (mm) US during low and high intensities (30% and 60% of maximal inspiratory pressure-MIP) with two modalities of inspiratory muscle loading mechanical threshold loading (MTL) and tapered flow-resistive loading (TFRL). RESULTS: Both MTL and TFRL produced a increase in Tdi, but only with high intensity loading compared to baseline-2.21 (0.26) vs. 2.68 (0.33) and 2.73 (0.44) mm; p = .01. TFdi was greater than baseline under all conditions, except during low intensity of TFRL. Diaphragm mobility was greater than baseline under all conditions, and high intensity of TFRL elicited greater mobility compared to all other conditions. Additionally, baseline Tdi was moderately correlated with pulmonary function tests. CONCLUSIONS: MTL and TFRL modalities elicit similar increases in diaphragm thickness at loads, but only during high intensity loading it was greater than baseline. Diaphragm mobility was significantly greater than baseline under both loads and devices, and at high intensity compared to low intensity, although TFRL produced greater mobility compared to modalities of inspiratory muscle loading. There is an association between diaphragm thickness and pulmonary function tests.

Ineficiência Ventilatória Comparável no Desempenho Máximo e Submáximo em Indivíduos com DPOC e ICC: Uma Abordagem Inovadora / Comparable Ventilatory Inefficiency at Maximal and Submaximal Performance in COPD vs. CHF subjects: An Innovative Approach

Resumo Fundamento: Atualmente, o excesso de ventilação tem sido fundamentado na relação entre ventilação-minuto/produção de dióxido de carbono ( V ˙ E − V ˙ CO 2). Alternativamente, uma nova abordagem para eficiência ventilatória ( η E V ˙) tem sido publicada. Objetivo: Nossa hipótese principal é que níveis comparativamente baixos de η E V ˙ entre insuficiência cardíaca crônica (ICC) e doença pulmonar obstrutiva crônica (DPOC) são atingíveis para um nível semelhante de desempenho aeróbico máximo e submáximo, inversamente aos métodos estabelecidos há muito tempo (inclinação V ˙ E − V ˙ CO 2 e intercepto). Métodos: Ambos os grupos realizaram testes de função pulmonar, ecocardiografia e teste de exercício cardiopulmonar. O nível de significância adotada na análise estatística foi 5%. Assim, dezenove indivíduos elegíveis para DPOC e dezenove indivíduos elegíveis para ICC completaram o estudo. Com o objetivo de contrastar valores completos de V ˙ E − V ˙ CO 2 e η E V ˙ para o período de exercício (100%), correlações foram feitas com frações menores, como 90% e 75% dos valores máximos. Resultados: Os dois grupos tiveram características correspondentes para a idade (62±6 vs 59±9 anos, p>.05), sexo (10/9 vs 14/5, p>0,05), IMC (26±4 vs 27±3 Kg m2, p>0,05), e pico V ˙ O 2 (72±19 vs 74±20 % pred, p>0,05), respectivamente. A inclinação V ˙ E − V ˙ CO 2 e intercepto foram significativamente diferentes para DPOC e ICC (207,2±1,4 vs 33,1±5,7 e 5,3±1,9 vs 1,7±3,6, p<0,05 para ambas), mas os valores médios da η E V ˙ foram semelhantes entre os grupos (10,2±3,4 vs 10,9±2,3%, p=0,462). As correlações entre 100% do período do exercício com 90% e 75% dele foram mais fortes para η E V ˙ (r>0,850 para ambos). Conclusão: A η E V ˙ é um método valioso para comparação entre doenças cardiopulmonares, com mecanismos fisiopatológicos até agora distintos, incluindo restrições ventilatórias na DPOC.

Abstract Background: Currently, excess ventilation has been grounded under the relationship between minute-ventilation/carbon dioxide output ( V ˙ E − V ˙ CO 2). Alternatively, a new approach for ventilatory efficiency ( η E V ˙) has been published. Objective: Our main hypothesis is that comparatively low levels of η E V ˙ between chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) are attainable for a similar level of maximum and submaximal aerobic performance, conversely to long-established methods ( V ˙ E − V ˙ CO 2 slope and intercept). Methods: Both groups performed lung function tests, echocardiography, and cardiopulmonary exercise testing. The significance level adopted in the statistical analysis was 5%. Thus, nineteen COPD and nineteen CHF-eligible subjects completed the study. With the aim of contrasting full values of V ˙ E − V ˙ CO 2 and η V ˙ E for the exercise period (100%), correlations were made with smaller fractions, such as 90% and 75% of the maximum values. Results: The two groups attained matched characteristics for age (62±6 vs. 59±9 yrs, p>.05), sex (10/9 vs. 14/5, p>0.05), BMI (26±4 vs. 27±3 Kg m2, p>0.05), and peak V ˙ O 2 (72±19 vs. 74±20 %pred, p>0.05), respectively. The V ˙ E − V ˙ CO 2 slope and intercept were significantly different for COPD and CHF (27.2±1.4 vs. 33.1±5.7 and 5.3±1.9 vs. 1.7±3.6, p<0.05 for both), but η V ˙ E average values were similar between-groups (10.2±3.4 vs. 10.9±2.3%, p=0.462). The correlations between 100% of the exercise period with 90% and 75% of it were stronger for η V ˙ E (r>0.850 for both). Conclusion: The η V ˙ E is a valuable method for comparison between cardiopulmonary diseases, with so far distinct physiopathological mechanisms, including ventilatory constraints in COPD.

Early Neuromuscular Electrical Stimulation Preserves Muscle Size and Quality and Maintains Systemic Levels of Signaling Mediators of Muscle Growth and Inflammation in Patients with Traumatic Brain Injury: A Randomized Clinical Trial.

Objective: To investigate the effects of an early neuromuscular electrical stimulation (NMES) protocol on muscle quality and size as well as signaling mediators of muscle growth and systemic inflammation in patients with traumatic brain injury (TBI). Design: Two-arm, single-blinded, parallel-group, randomized, controlled trial with a blinded assessment. Setting. Trauma intensive care unit at a university hospital. Participants. Forty consecutive patients on mechanical ventilation (MV) secondary to TBI were prospectively recruited within the first 24 hours following admission. Interventions. The intervention group (NMES; n = 20) received a daily session of NMES on the rectus femoris muscle for five consecutive days (55 min/each session). The control group (n = 20) received usual care. Main Outcome Measures. Muscle echogenicity and thickness were evaluated by ultrasonography. A daily blood sample was collected to assess circulating levels of insulin-like growth factor I (IGF-I), inflammatory cytokines, and matrix metalloproteinases (MMP). Results: Both groups were similar at baseline. A smaller change in muscle echogenicity and thickness (difference between Day 1 and Day 7) was found in the control group compared to the NMES group (29.9 ± 2.1 vs. 3.0 ± 1.2, p < 0.001; -0.79 ± 0.12 vs. -0.01 ± 0.06, p < 0.001, respectively). Circulating levels of IGF-I, pro-inflammatory cytokines (IFN-y), and MMP were similar between groups. Conclusion: An early NMES protocol can preserve muscle size and quality and maintain systemic levels of signaling mediators of muscle growth and inflammation in patients with TBI. This trial is registered with https://www.ensaiosclinicos.gov.br under number RBR-2db.

Inspiratory muscle training on quality of life in individuals with spinal cord injury: A systematic review and meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: The objective was to summarize the effectiveness of Inspiratory Muscle Training (IMT) on the quality of life in individuals with Spinal Cord Injury (SCI). METHODS: An online systematic literature search was conducted in the following databases: PubMed/MEDLINE, PubMed CENTRAL, EMBASE, ISI Web of Science, SciELO, CINAHL/SPORTDiscus, and PsycINFO. Randomized and non-randomized clinical studies investigating the effectiveness of IMT in quality of life were included in the present study. The results used the mean difference and 95% confidence interval for maximal inspiratory pressure (MIP), forced expiratory volume in 1 s (FEV1), maximal expiratory pressure (MEP), and the standardized mean differences for the quality of life and maximum ventilation volume. RESULTS: The search found 232 papers, and after the screening, four studies met the inclusion criteria and were included in the meta-analytical procedures (n = 150 participants). No changes were demonstrated in the quality of life domains (general health, physical function, mental health, vitality, social function, emotional problem, and pain) after IMT. The IMT provided a considerable effect over the MIP but not on FEV1 and MEP. Conversely, it was not able to provide changes in any of the quality of life domains. None of the included studies evaluated the IMT effects on the expiratory muscle maximal expiratory pressure. CONCLUSION: Evidence from studies shows that inspiratory muscle training improves the MIP; however, this effect does not seem to translate to any change in the quality of life or respiratory function outcomes in individuals with SCI.

Efficacy of home-based inspiratory muscle training in patients post-covid-19: Protocol for a randomized clinical trial.

INTRODUCTION: Current evidence suggests the emergence of a novel syndrome (long COVID syndrome) due to sequels and persistent COVID-19 symptoms. Respiratory muscle training improves respiratory muscle strength, exercise capacity, diaphragm thickness, and dyspnea, especially in patients with decreased respiratory muscle strength. This study aims to evaluate the effectiveness of a protocol for home-based inspiratory muscle training to improve respiratory muscle strength, dyspnea, and quality of life of patients post-COVID-19. METHODS AND ANALYSES: This randomized, controlled, double-blind clinical trial will be conducted at the Instituto de Medicina Tropical of Universidade Federal do Rio Grande do Norte (Brazil). Sample size will be determined using maximal inspiratory pressure after a pilot study with five patients per group (total of 10 patients). Patients included in the study will be evaluated in three moments: pre-training (initial), post-training (three weeks), and retention (24 weeks). The sample will be randomized in two groups: active (IMT using 30% of IMT and load increase of 10% of initial IMT every week. Patients will perform 30 repetitions, twice a day (morning and afternoon), for seven consecutive days, and six weeks) and SHAM (IMT without load). The following measurements will be assessed: anthropometry, respiratory muscle strength, pulmonary volume and capacity, dyspnea, perception of effort and lower limb fatigue, handgrip strength, functional capacity, anxiety, depression, and functional status. After initial evaluation, all patients will receive a POWERbreathe® (POWERbreathe®, HaB Ltd, Southam, UK) device to perform the training. Normality will be verified using Shapiro-Wilk or Kolmogorov-Smirnov, according to the number of patients included. Variables presenting nonparametric distribution will be compared using Wilcoxon (intragroup analysis) and Mann-Whitney test (intergroup analysis), whereas repeated measures two-way ANOVA will be performed in case of parametric distribution. Dunn's post hoc test will be used to identify significant differences in the two-way ANOVA test. PRIMARY OUTCOMES: Respiratory muscle strength, dyspnea, and quality of life of post-COVID-19 patients. SECOND OUTCOMES: Pulmonary function, dyspnea, exercise tolerance, handgrip strength, anxiety, depression, and functional status. TRIAL REGISTRATION: Trial register number NCT05077241.

Acute hemodynamic responses from low-load resistance exercise with blood flow restriction in young and older individuals: A systematic review and meta-analysis of cross-over trials.

OBJECTIVE: To summarize the existing evidence on the acute response of low-load (LL) resistance exercise (RE) with blood flow restriction (BFR) on hemodynamic parameters. DATA SOURCES: MEDLINE (via PubMed), EMBASE (via Scopus), SPORTDiscus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Science and MedRxiv databases were searched from inception to February 2022. REVIEW METHODS: Cross-over trials investigating the acute effect of LLRE + BFR versus passive (no exercise) and active control methods (LLRE or HLRE) on heart rate (HR), systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure responses. RESULTS: The quality of the studies was assessed using the PEDro scale, risk of bias using the RoB 2.0 tool for cross-over trials and certainty of the evidence using the GRADE method. A total of 15 randomized cross-over studies with 466 participants were eligible for analyses. Our data showed that LLRE + BFR increases all hemodynamic parameters compared to passive control, but not compared to conventional resistance exercise. Subgroup analysis did not demonstrate any differences between LLRE + BFR and low- (LL) or high-load (HL) resistance exercise protocols. Studies including younger volunteers presented higher chronotropic responses (HR) than those with older volunteers. CONCLUSIONS: Despite causing notable hemodynamic responses compared to no exercise, the short-term LL resistance exercise with BFR modulates all hemodynamic parameters HR, SBP, DBP and MBP, similarly to a conventional resistance exercise protocol, whether at low or high-intensity. The chronotropic response is slightly higher in younger healthy individuals despite the similarity regarding pressure parameters.

Muscle-Skeletal Abnormalities and Muscle Oxygenation during Isokinetic Strength Exercise in Heart Failure with Preserved Ejection Fraction Phenotype: A Cross-Sectional Study.

Exercise intolerance, a hallmark of patients with heart failure (HF), is associated with muscle weakness. However, its causative microcirculatory and muscle characteristics among those with preserved or reduced ejection fraction (HFpEF or HFrEF) phenotype is unclear. The musculoskeletal abnormalities that could result in impaired peripheral microcirculation are sarcopenia and muscle strength reduction in HF, implying lowered oxidative capacity and perfusion affect transport and oxygen utilization during exercise, an essential task from the microvascular muscle function. Besides that, skeletal muscle microcirculatory abnormalities have also been associated with exercise intolerance in HF patients who also present skeletal muscle myopathy. This cross-sectional study aimed to compare the muscle microcirculation dynamics via near-infrared spectroscopy (NIRS) response during an isokinetic muscle strength test and ultrasound-derived parameters (echo intensity was rectus femoris muscle, while the muscle thickness parameter was measured on rectus femoris and quadriceps femoris) in heart failure patients with HFpEF and HFrEF phenotypes and different functional severities (Weber Class A, B, and C). Twenty-eight aged-matched patients with HFpEF (n = 16) and HFrEF (n = 12) were assessed. We found phenotype differences among those with Weber C severity, with HFrEF patients reaching lower oxyhemoglobin (O2Hb, µM) (-10.9 ± 3.8 vs. -23.7 ± 5.7, p = 0.029) during exercise, while HFpEF reached lower O2Hb during the recovery period (-3.0 ± 3.4 vs. 5.9 ± 2.8, p = 0.007). HFpEF with Weber Class C also presented a higher echo intensity than HFrEF patients (29.7 ± 8.4 vs. 15.1 ± 6.8, p = 0.017) among the ultrasound-derived variables. Our preliminary study revealed more pronounced impairments in local microcirculatory dynamics in HFpEF vs. HFrEF patients during a muscle strength exercise, combined with muscle-skeletal abnormalities detected via ultrasound imaging, which may help explain the commonly observed exercise intolerance in HFpEF patients.

Acute and Time-Course Effects of Osteopathic Manipulative Treatment on Vascular and Autonomic Function in Patients With Heart Failure: A Randomized Trial.

OBJECTIVE: The purposed of this study was to valuate the effect of osteopathic manipulative treatment (OMT) on flow-mediated dilation and heart rate variability of patients with heart failure. BACKGROUND: Osteopathic manipulative treatment modulates both the vascular and autonomic nervous system (ANS) in healthy volunteers. However, the acute and time-course effects of the OMT on patients with an overactive ANS remain unclear. METHODS: This randomized controlled trial study included 20 patients with heart failure aged 50 to 60 years, allocated to a single session of OMT (base of the skull, retromaxillary region, heart, and thoracic duct) or sham. Flow-mediated dilation (FMD) at the brachial artery, hemodynamic measures, and heart rate variability were assessed in 3 periods (baseline, immediately after the intervention, and after 15 minutes). Multivariate analysis of variance procedure was used to compare intervention and periods. RESULTS: The OMT group had a greater FMD modulation compared with the sham (FMD,% =  9.5 vs. -5.6, 95% confidence interval (CI): [6.6, -12.35] vs. [-14.25, 2.8]; p = 0.001) and grater peak diameter (PD, mm =  0.77 vs -0.16 mm, 95% CI: [0.31,-1.24] vs [-0.63, 0.29]; P =  0.001), suggesting an important acute and time-course vascular effect from OMT. We also found some relevant heart rate variability modulation after 15 minutes from OMT: high frequency (HF, ms2 = 295 vs -354, 95% CI: [144.2, -769]; P = .001) and low frequency (LF, ms2) = 670 vs 775, 95% CI: [-98, 3591]; P = .001), suggesting a time-course ANS modulation after OMT. CONCLUSIONS: Osteopathic manipulative treatment was effective at increasing brachial blood flow and stimulating the vagal system in patients with heart failure. Moreover, vascular changes seem to precede the autonomic modulation.

Moderate-intensity exercise with blood flow restriction on cardiopulmonary kinetics and efficiency during a subsequent high-intensity exercise in young women: A cross-sectional study.

ABSTRACT: Blood flow restriction (BFR) training applied prior to a subsequent exercise has been used as a method to induce changes in oxygen uptake pulmonary kinetics (O2P) and exercise performance. However, the effects of a moderate-intensity training associated with BFR on a subsequent high-intensity exercise on O2P and cardiac output (QT) kinetics, exercise tolerance, and efficiency remain unknown.This prospective physiologic study was performed at the Exercise Physiology Lab, University of Brasilia. Ten healthy females (mean ±â€ŠSD values: age = 21.3 ±â€Š2.2 years; height = 1.6 ±â€Š0.07 m, and weight = 55.6 ±â€Š8.8 kg) underwent moderate-intensity training associated with or without BFR for 6 minutes prior to a maximal high-intensity exercise bout. O2P, heart rate, and QT kinetics and gross efficiency were obtained during the high-intensity constant workload exercise test.No differences were observed in O2P, heart rate, and QT kinetics in the subsequent high-intensity exercise following BFR training. However, exercise tolerance and gross efficiency were significantly greater after BFR (220 ±â€Š45 vs 136 ±â€Š30 seconds; P < .05, and 32.8 ±â€Š6.3 vs 27.1 ±â€Š5.4%; P < .05, respectively), which also resulted in lower oxygen cost (1382 ±â€Š227 vs 1695 ±â€Š305 mL min-1).We concluded that moderate-intensity BFR training implemented prior to a high-intensity protocol did not accelerate subsequent O2P and QT kinetics, but it has the potential to improve both exercise tolerance and work efficiency at high workloads.

Failure of Noninvasive Ventilation in Acute Respiratory Failure is Associated with Higher Mortality in Patients with Solid Tumors: A Retrospective Cohort Study.

BACKGROUND: Noninvasive Ventilation (NIV) is a well-established treatment for Acute Respiratory Failure (ARF) in hematological cancer. However, the NIV impact on mortality in patients with solid tumors is unclear. OBJECTIVE: To define the factors associated with NIV failure and mortality and to describe the mortality risk of patients with solid tumors requiring NIV for ARF treatment in the intensive care unit (ICU). METHODS: A retrospective cohort study of patients with solid tumors admitted into an ICU between Jan 2016 and Dec 2017, for cancer treatment, with ARF diagnosis that had used the NIV as first-line treatment. Our primary outcome was ICU and in-hospital mortality. The secondary outcome was NIV failure. A Cox proportional hazards regression was used to identify variables associated with mortality and NIV failure. Kaplan-Meier analyses were performed to demonstrate cumulative survival. RESULTS: A total of 226 patients with solid tumors were included. The ICU and hospital mortality rates were 57.5% and 69.5%, respectively. NIV failed in 52.2% of the patients. The use of vasopressors (HR 2.48 [95% CI: 1.43-4.30] p = 0.001), baseline lactate (HR 1.20 [95% CI: 1.07-1.35] p = 0.003), baseline PaO2/FiO2 ratio (HR1.33 [1.11-1.55] p = 0.002), and NIV success (HR0.17 [95% CI: 0.10-0.27] p = 0.005) was independently associated with hospital mortality. The use of vasopressors (HR 2.58 [95% CI: 1.41-4.73] p = 0.02), NIV duration (HR 0.93 [95% CI: 0.89-0.97] p = 0.003), and baseline lactate (HR 1.13 [95% CI: 1.06-1.20] p = 0.001) was associated with NIV failure. CONCLUSIONS: NIV failure was independently associated with an increase in both ICU and hospital mortality rates. In patients with NIV therapy indication, the duration of this intervention was associated with NIV failure.

Maximal Dynamic Inspiratory Pressure Evaluation in Heart Failure: A Comprehensive Reliability and Agreement Study.

OBJECTIVE: The purpose of this study was to analyze the reliability (interrater and intrarater) and agreement (repeatability and reproducibility) properties of tapered flow resistive loading (TFRL) measures in patients with heart failure (HF). METHODS: For this cross-sectional study, participants were recruited from the cardiopulmonary rehabilitation program at the University of Brasilia from July 2015 to July 2016. All patients participated in the study, and 10 were randomly chosen for intrarater and interrater reliability testing. The 124 participants with HF (75% men) were 57.6 (SD = 1.81) years old and had a mean left ventricular ejection fraction of 38.9% (SD = 15%) and a peak oxygen consumption of 13.05 (SD = 5.3) mL·kg·min-1. The main outcome measures were the maximal inspiratory pressure (MIP) measured with a standard manovacuometer (SM) and the MIP and maximal dynamic inspiratory pressure (S-Index) obtained with TFRL. The S-Index reliability (interrater and intrarater) was examined by 2 evaluators, the S-Index repeatability was examined with 10 repetitions, and the reproducibility of the MIP and S-Index was measured with SM and TFRL, respectively. RESULTS: The reliability analysis revealed high S-Index interrater and intrarater reliability values (intraclass correlation coefficients [ICCs] of 0.89 [95% CI = 0.58-0.98] and 0.97 [95% CI = 0.89-0.99], respectively). Repeatability analyses revealed that 8 maneuvers were required to reach the maximum S-Index in 75.81% (95% CI = 68.27-83.34) of the population. The reproducibility of TFRL measures (S-Index = 68.8 [SD = 32.8] cm H2O; MIP = 66 [SD = 32.3] cm H2O) was slightly lower than that of the SM measurement (MIP = 70.1 [SD = 35.9] cm H2O). CONCLUSIONS: The TFRL device provided a reliable intrarater and interrater S-Index measure in patients with HF and had acceptable repeatability, requiring 8 maneuvers to produce a stable S-Index measure. The reproducibilities of the S-Index, MIP obtained with SM, and MIP obtained with TRFL were similar. IMPACT: TRFL is a feasible method to assess both MIP and the S-index as measures of inspiratory muscle strength in patients with HF and can be used for inspiratory muscle training, making the combined testing and training capabilities important in both clinical research and the management of patients with HF.

Neuromuscular electrical stimulation combined with exercise decreases duration of mechanical ventilation in ICU patients: A randomized controlled trial.

BACKGROUND: Early mobilization can be employed to minimize the duration of intensive care. However, a protocol combining neuromuscular electrical stimulation (NMES) with early mobilization has not yet been tested in ICU patients. Our aim was to assess the efficacy of NMES, exercise (EX), and combined therapy (NMES + EX) on duration of mechanical ventilation (MV) in critically ill patients. METHODS: The participants in this randomized double-blind trial were prospectively recruited within 24 hours following admission to the intensive care unit of a tertiary hospital. Eligible patients had 18 years of age or older; MV for less than 72 hours; and no known neuromuscular disease. Computer-generated permuted block randomization was used to assign patients to NMES, EX, NMES + EX, or standard care (control group). The main endpoint was duration of MV. Clinical characteristics were also evaluated and intention to treat analysis was employed. RESULTS: One hundred forty-four patients were assessed for eligibility to participate in the trial, 51 of whom were enrolled and randomly allocated into four groups: 11 patients in the NMES group, 13 in the EX group, 12 in the NMES + EX group, and 15 in the control group (CG). Duration of MV (days) was significantly shorter in the combined therapy (5.7 ± 1.1) and NMEN (9.0 ± 7.0) groups in comparison to CG (14.8 ± 5.4). CONCLUSIONS: NMES + EX consisting of NMES and active EXs was well tolerated and resulted in shorter duration of MV in comparison to standard care or isolated therapy (NMES or EX alone).

Inspiratory muscle strength and six-minute walking distance in heart failure: Prognostic utility in a 10 years follow up cohort study.

BACKGROUND: Maximal inspiratory pressure (PImax) and 6-minutes walk distance test (6MWD) may be more available and feasible alternatives for prognostic assessment than cardiopulmonary testing. We hypothesized that the PImax and 6MWD combination could improve their individual accuracy as risk predictors. We aimed to evaluate PImax ability as a mortality predictor in HF and whether the combination to 6MWD could improve risk stratification. METHODS: Prospective cohort from HF Clinics of three University Hospitals. PImax, 6MWD and pVO2 were obtained at baseline. The end point was all cause mortality. RESULTS: Consecutive 256 individuals (50% woman, 57.4±10.4years) with low ejection fraction (LVEF) (31.8±8.6%) were followed up to 10years. During a median follow-up of 34.7 (IQR 37) months, 110 participants died. Mean±SD values were: pVO2 14.9±5.1mL/kg/min, PImax 5.5±1.3kPa and 6MWD 372±118m. In multivariate Cox regression, pVO2, PImax, 6MWD and LVEF were independent mortality predictors. The pVO2 showed gold standard accuracy, followed by PImax (AUC = 0.84) and 6MWD (AUC = 0.74). Kaplan-Meier mean survival time (MST±SE) for lower (≤5.0kPa) and higher (>6.0kPa) PImax tertiles, were 37.9±2.8months and 105.0±5.2months respectively, and addition of 6MWD did not restratified risk. For intermediate PImax tertile, MST was 81.5±5.5months, but adding 6MWD, MST was lower (53.3±7.6months) if distance was ≤350m and higher (103.1±5.7months) for longer distances. CONCLUSION: PImax is an independent mortality predictor in HF, more accurate than 6MWD and LVEF. Addition of 6MWD empowers risk stratification only for intermediate PImax tertile. Although less accurate than pVO2, this simpler approach could be a feasible alternative as a prognostic assessment.

Current insights of inspiratory muscle training on the cardiovascular system: a systematic review with meta-analysis.

Background: Cardiorespiratory limitation is a common hallmark of cardiovascular disease which is a key component of pharmacological and exercise treatments. More recently, inspiratory muscle training (IMT) is becoming an effective complementary treatment with positive effects on muscle strength and exercise capacity. We assessed the effectiveness of IMT on the cardiovascular system through autonomic function modulation via heart rate variability and arterial blood pressure. Methods: Randomized controlled trials (RCTs) were identified from searches of The Cochrane Library, MEDLINE and EMBASE to November 2018. Citations, conference proceedings and previous reviews were included without population restriction, comparing IMT intervention to no treatment, placebo or active control. Results: We identified 10 RCTs involving 267 subjects (mean age range 51-71 years). IMT programs targeted maximum inspiratory pressure (MIP) and cardiovascular outcomes, using low (n=6) and moderate to high intensity (n=4) protocols, but the protocols varied considerably (duration: 1-12 weeks, frequency: 3-14 times/week, time: 10-30 mins). An overall increase of the MIP (cmH2O) was observed (-27.57 95% CI -18.48, -37.45, I 2=64%), according to weighted mean difference (95%CI), and was accompanied by a reduction of the low to high frequency ratio (-0.72 95% CI-1.40, -0.05, I 2=50%). In a subgroup analysis, low- and moderate-intensity IMT treatment was associated with a reduction of the heart rate (HR) (-7.59 95% CI -13.96, -1.22 bpm, I 2=0%) and diastolic blood pressure (DBP) (-8.29 [-11.64, -4.94 mmHg], I 2=0%), respectively. Conclusion: IMT is an effective treatment for inspiratory muscle weakness in several populations and could be considered as a complementary treatment to improve the cardiovascular system, mainly HR and DBP. Further research is required to better understand the above findings.

Faster oxygen uptake, heart rate, and ventilatory kinetics in stepping compared with cycle ergometry in patients with COPD during moderate-intensity exercise.

Step tests are a stressful and feasible cost-effective modality to evaluate aerobic performance. However, the eccentric in addition to concentric muscle contractions of the legs on stepping emerge as a potential speeding factor for cardioventilatory and metabolic adjustments towards a steady-state, since eccentric contractions would prompt an earlier and stronger mechanoreceptor activation, as well as higher heart rate/cardiac output adjustments to the same metabolic demand. Moreover, shorter tests are ideal for exercise-limited subjects. Nine subjects with chronic obstructive pulmonary disease were invited to participate in comprehensive lung function tests and constant work tests performed on different days at a 90% gas exchange threshold for 6 min, in single-step tests or cycle ergometry. After careful monoexponential regression modelling, statistically relevant faster phase II time constants for oxygen uptake (45 ± 18 s vs 53 ± 17 s, p = 0.017) and minute ventilation (61 ± 13 s vs 74 ± 17 s, p = 0.027) were observed in the 6-min step tests compared with cycle ergometry, respectively. Despite an absence of heart rate time constant difference (43 ± 20 s vs 69 ± 46 s, p = 0.167), there was a significantly faster rate constant toward a steady state for heart rate (p = 0.02). In addition, 4-min compared with 6-min analysis presented similar results (p > 0.05), providing an appropriate steady-state. We conclude that step tests might elicit faster time constants compared with cycle ergometry, at the same average metabolic level, and 4-min analysis has similar mean errors compared with 6-min analysis within an acceptable range. New studies, comprising mechanisms and detailed physiological backgrounds, are necessary.