Efficacy of noninvasive ventilatory support on exercise tolerance in patients with heart failure: a systematic review

The aim of this study was evaluate the efficacy of noninvasive ventilation (NIV) on improving exercise tolerance of patients with heart failure (HF). A systematic review was performed in PubMed/ MEDLINE, LILACS, Cochrane, CINAHL, Scopus and Web of Science for randomized and quasi-randomized clinical trials, without language and year of publication restrictions. Descriptors were defined as 'heart failure', 'noninvasive ventilation', 'positive-pressure respiration', 'interactive ventilatory support', 'exercise test' in addition to the keywords 'BIPAP', 'CPAP', 'IPAP', 'EPAP', 'NIV' and their Portuguese equivalents. Studies comparing NIV with one or two pressure levels to groups without intervention, other physiotherapy modalities without positive pressure or a sham group were included. Four studies were selected, including HF patients of various etiologies, considering the staging classification of New York Heart Association. Any included work realized the allocation concealment, all studies participants underwent blinding, but only two trials performed assessors blinding. None of the studies have described an intention to treat analysis and did not use appropriate statistical methods. All selected trials assessed functional capacity and in only two, dyspnea was assessed. The intervention protocols of the included trials were heterogeneous, three studies underwent a single intervention with NIV, two immediately before the functional capacity test and another study performed NIV during the exercise evaluation. The last trial held 14 sessions of NIV, with the functional capacity evaluation being performed on day 0, 4, 9 and 14. There is insufficient evidence on the effectiveness of NIV in increasing exercise tolerance.本研究旨在评估无创通气（noninvasive ventilation, NIV）对改善心力衰竭（heart failure, HF）患者运动耐量的疗效。本研究在PubMed/MEDLINE、LILACS、Cochrane、CINAHL、Scopus及Web of Science数据库中开展系统综述，检索无语言及出版年份限制的随机与半随机临床试验。本研究设定的主题词为“心力衰竭”、“无创通气”、“正压呼吸（positive-pressure respiration）”、“交互式通气支持（interactive ventilatory support）”、“运动试验（exercise test）”，同时辅以关键词“BIPAP”、“CPAP”、“IPAP”、“EPAP”、“NIV”及其葡萄牙语对应术语。纳入旨在对比无创通气单/双压力水平与无干预组、非正压其他物理治疗方案组或假干预组的临床试验。最终纳入4项研究，研究对象为符合纽约心脏病协会（New York Heart Association, NYHA）分期标准的不同病因心力衰竭患者。所有纳入研究均实施了分配隐藏，所有研究对象均采用了分组盲法，但仅2项试验实施了评价者盲法。所有纳入研究均未开展意向性治疗分析，且未采用恰当的统计学方法。所有入选试验均评估了患者的功能容量，仅2项试验评估了呼吸困难症状。纳入试验的干预方案异质性较强：3项研究仅实施单次无创通气干预，其中2项于功能容量测试前即刻开展，1项于运动评估过程中实施无创通气；剩余1项试验共开展14次无创通气干预，并于第0、4、9、14天完成功能容量评估。目前尚无充分证据证实无创通气可提升心力衰竭患者的运动耐量。