Ventilator-based Inspiratory Muscle Training for Patients With Respiratory Failure

Acute respiratory failure (ARF) remains a leading contributor to morbidity and mortality in intensive care settings. It accounts for approximately 10% to 15% of medical ICU admissions and up to 50% to 75% of prolonged ICU stays exceeding seven days, with a reported mortality rate of around 40%. Inspiratory muscle weakness is common in mechanically ventilated patients, particularly with prolonged ventilation. Inspiratory muscle training could limit or reverse these detrimental effects and promote quicker, successful weaning. Unfortunately, especially when the weaning process started late, the significant loss of muscle strength means that between 5% and 15% of patients being weaned repeatedly fail to regain respiratory autonomy. Several strategies aim to reduce weaning duration and MV time in patients requiring prolonged ventilation, including inspiratory muscle training (IMT); however, evidence for its effectiveness remains limited and inconsistent. Alternatively, ventilator-based approaches such as trigger sensitivity optimization or gradual pressure support (PS) reduction offer valid equipment-free methods that may preserve muscle activity and enhance synchrony. Despite their potential, these strategies have not been rigorously evaluated in randomized controlled trials.

Inclusion criteria

• Acute respiratory failure patients in the ICU are receiving MV for 48 h or more in a controlled mode.
• Their ages will range from 40 to 55 years old, and both sexes will be included.
• Conscious and oriented patients with a Glasgow coma score ≥13 (≥9T).
• Alertness score with a Richmond Agitation-Sedation Scale (RASS) will be from 0 to -1.
• All patients in this study must be hemodynamically and medically stable.
• Patients must be able to trigger spontaneous breaths on the ventilator but couldn't generate maximum inspiratory pressure more than -15 mbar.

Exclusion criteria

• Persistent hemodynamic instability as life-threatening conditions or comorbidities interfere with and compromise weaning, like cardiac arrhythmia, pericardial effusion, congestive heart failure, or acute coronary syndrome.
• Severe breathlessness when spontaneously breathing.
• Any progressive neuromuscular disease, such as myopathy or neuropathy, that would interfere with responding to inspiratory muscle training due to inadequate training performance of the inspiratory muscle.
• Spinal cord injury.
• Skeletal pathology (scoliosis, flail chest, spinal instrumentation) that would seriously impair the movement of the chest wall and ribs.
• Patients in a coma or under heavy sedation (RASS ≤ -2) and with respiratory muscle paralysis.
• High peak airway pressure (barotrauma), high PEEP >10, or active pneumothorax.