Effects of Inspiratory Muscle Training on Inspiratory Muscle Strength in Hospitalized Heart Failure Patients: A Randomized Clinical Trial
Introduction Exercise intolerance is the most common symptom in patients with heart failure (HF), significantly impacting their quality of life and functional capacity. Muscle metabolism may be impaired due to sympathetic hyperactivation, systemic inflammation, and neurohormonal alterations, contributing to ventilatory inefficiency and exercise intolerance. Inspiratory muscle training (IMT) has been shown to improve inspiratory muscle strength and endurance, reducing fatigue and the sensation of dyspnea. There is a gap in the evidence regarding the use of IMT in hospitalized settings, particularly concerning short-term gains in inspiratory muscle strength and the safety of the intervention. This study aims to evaluate the effects of IMT on inspiratory muscle strength, hemodynamic and functional outcomes, as well as the safety of the IMT protocol in hospitalized patients with HF. Methods A randomized, controlled clinical trial will be conducted in the Cardiac Intensive Care Unit of the University Hospital Pedro Ernesto. The study will include individuals of both sexes, aged 18 years or older, who are hospitalized due to heart failure. Exclusion criteria will include: pregnancy; head trauma and/or brain injury; motor disability; signs and/or symptoms of low cardiac output; acute coronary syndrome; advanced HF with left ventricular ejection fraction (LVEF) below 20%; presence of untreated tachyarrhythmias or bradyarrhythmias; use of high-dose inotropes or vasopressors or an increase in their dose within the past 24 hours. Primary outcomes will include inspiratory muscle strength, safety, functional status, length of stay in the ICU, and hospital readmission within 90 days. After randomization, the intervention group will undergo IMT with a load between 30% and 50% of maximal inspiratory pressure (MIP), while the control group will perform IMT without load. It is expected that IMT will be safe and lead to improvements in inspiratory muscle strength and functional status, without significant hemodynamic repercussions.
• Diagnosis of heart failure;
• age over 18 years;
• hospital admission due to heart failure;
• clinical and hemodynamic stability defined as: heart rate \> 40 bpm and \< 130 bpm; systolic blood pressure (SBP) \> 90 mmHg and \< 180 mmHg; mean arterial pressure (MAP) \> 60 mmHg and \< 110 mmHg; respiratory rate \> 5 breaths per minute and \< 40 breaths per minute; peripheral oxygen saturation \> 88%; absence of psychomotor agitation or somnolence