CPAP Versus Bi-level in Chronic Heart Failure
Condition: Heart Failure
MeSH terms: Heart Failure
Study type: Interventional

Summary: 
      Introduction: Dyspnea and fatigue are the main clinical symptoms of heart failure and
      primarily responsible for exercise intolerance found in this syndrome. Now, It is known that
      the use of NIV in CPAP mode applied before exercise increases exercise tolerance in people
      with heart failure; however, it's not yet known if the bi-level mode is able to generate
      similar or even better results, due to pressure increase of the ventilatory support in this
      modality. Moreover, it is possible that there is influence between the pressure levels set in
      the NIV and the magnitude of its effect on the exercise in this population Objective: 1) test
      for differences between the acute effects of NIV on exercise tolerance in patients with HF,
      when applied CPAP or bi-level mode; and 2) check for discrepancies in the acute effects of
      Bi-level mode on the physical performance of these individuals, when applied at different
      pressure levels. Methodology: This is a controlled, randomized, double-blind and cross-over
      clinical trial, to be composed of 45 volunteers of both genders, aged between 30 and 80
      years, with chronic heart failure, functional class II and III (New York Heart Association)
      in clinical stability. The experiment will be carried out on four different days, with a
      48-hour interval between them, in which NIV will be used in the following modes: Bi-level
      with minimum parameters (EPAP = 6 cmH2O and IPAP = 12 cmH2O), Bi-level with maximum
      parameters EPAP = 8 cmH2O and IPAP = 14 cmH2O) and CPAP (6 cmH2O). Thus, all the volunteers
      will participate in the four TGC. During the tests, distance walking, perceived levels of
      fatigue and dyspnea, affective response, as well as other physiological variables will be
      analyzed. Statistical analysis, the ANOVA test for repeated measurements will be used,
      followed by the Bonferroni post-test, considering p-value less than or equal to 0.05 as
      statistically significant. Expected Results: This work is expected to improve the therapeutic
      management of HF patients, assisting in the implementation and improvement of methods to
      improve dyspnea and muscle fatigue, thus increasing tolerance to exercise.
    

Detailed description: 
      This study is a randomized controlled trial, double-blind and cross-over, to be composed of
      45 volunteers of both genders, aged between 30 and 80 years, with CHF will be selected from a
      specialized outpatient clinic with medical consent. Patients should have symptoms of
      compensated CHF; presenting functional capacity II and III (New York Heart Association), with
      left ventricular ejection fraction <50%; not participating in cardiac rehabilitation
      programs; and clinical stability in the last three months, with no history of angina or
      coexistence of obstructive pulmonary disease (Tiffeneau-Pinelli index> 70% in spirometry). In
      addition, they should not present any osteoarticular or neurological disease would prevents
      them from performing the proposed tests, as well as having a score higher than 22 in the
      Leganés cognitive test (20). In the case of NIV or exercise intolerance, as well as in case
      of non-attendance to the experiments on the scheduled days, subjects will be excluded from
      the study.

      The sample will be the result of a non-probabilistic sampling process, calculated based on
      the magnitude of the effect of the main variable (distance traveled) after the use of NIV
      therapy, obtained in a pilot study. In addition, this protocol was aproved by the
      institution's Ethics Committee on Human Research (CAAE: 49324415.0.000.5537).

      Experimental procedure The experimental protocol will occur in three visits, one per day,
      with a minimum interval of 48 hours between them. On the first visit, the volunteers will
      undergo a screening that consists of clinical evaluation (assessment sheet) and cognitive
      (Leganéscognitive test), as well as evaluation of lung function (spirometry) and QoL
      (Minnesota Living with Heart Failure Questionnaire). Next, the Shuttlel Walking Test (SWT)
      control (T-Co) will be performed, without previous use of NIV, in order to determine the
      distance traveled and other physiological variables in the absence of interventions. Finally,
      during the initial visit, a preliminary NIV session will be held to adjust the interface and
      adapt the volunteer to the therapy.

      At each subsequent visit, volunteers will perform a SWT immediately after 30 minutes of NIV,
      one day in Bi-level mode and one in CPAP mode, following a randomized sequence. Thus, all
      volunteers will perform one SWT after CPAP (T-CP) and one SWT after Bi-level (T-Bi). In the
      experiment, the CPAP pressure will be maintained at 6 cmH2O, while at the Bi-level an
      expiratory pressure (EPAP) of 6 cmH2O and an inspiratory pressure (IPAP) of 12 cmH2O will be
      defined.
    

Intervention name(s): Shuttle walk test; Noninvasive ventilation (Bi-pap); Noninvasive ventilation (CPAP)
Intervention type(s): Diagnostic Test; Device; Device
Intervention description(s): A shuttle walk test was performed without any previous intervention.; After 30 minutes of the mentioned intervention, the subject performed a shuttle walk test.; After 30 minutes of the mentioned intervention, the subject performed a shuttle walk test.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: noninvasive ventilation; continuous positive airway pressure; intermittent positive-pressure breathing; exercise test; physical endurance; physical fitness