Mechanical Power During Pressure Controlled Versus Volume-Controlled Ventilation in Acute Respiratory Failure

Mechanical ventilation is a life-saving intervention for critically ill patients with acute respiratory failure. However, mechanical ventilation can also contribute to ventilator-induced lung injury when excessive energy is delivered to the respiratory system. Mechanical power, which represents the energy transferred from the ventilator to the respiratory system per unit of time, has emerged as a potentially important parameter for assessing the intensity of mechanical ventilation.

The mode of ventilation may influence mechanical power through changes in airway pressure, tidal volume, respiratory rate, and inspiratory flow. Pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) are commonly used modes of invasive mechanical ventilation, but their effects on mechanical power in critically ill patients may differ.

Therefore, this prospective observational cohort study aims to compare mechanical power between PCV and VCV in critically ill adult patients receiving invasive mechanical ventilation and to evaluate the relationship between mechanical power and relevant clinical outcomes.

Inclusion criteria

• Adult patients aged >18 years.
• Patients with acute respiratory failure who are receiving invasive mechanical ventilation.

Exclusion criteria

• Patients whose condition requires shifting between VCV and PCV after enrollment.
• Patients with neurological, neuromuscular, or muscular disorders.
• Neurological disorders, e.g., stroke, multiple sclerosis, Parkinsonism, and Guillain-Barré syndrome.
• Neuromuscular junction disorders, e.g., myasthenia gravis.
• Muscular disorders, e.g., polymyositis and Duchenne muscular dystrophy.
• Chest wall abnormalities, e.g., kyphoscoliosis, scoliosis, and pectus excavatum.
• Tracheostomized patients.
• Patients with raised intra-abdominal pressure (IAP ≥12 mmHg), as estimated by transvesical manometry e.g., massive ascites, bowel obstruction, and postoperative abdominal surgery.
• Patients with documented chronic type 2 respiratory failure, characterized by an elevated partial pressure of carbon dioxide (PaCO₂ >45 mmHg), low partial pressure of oxygen (PaO₂), and chronically elevated bicarbonate (HCO₃-) reflecting renal compensation.