Analysis of mechanical power during pressure-controlled ventilation in patients with severe burns

Introduction: The clinical evolution of severe burns can lead to Acute Respiratory Distress Syndrome (ARDS) with increased requirements for mechanical ventilation, which may lead to the development of Ventilator-Induced Lung Injury (VILI). Together, ARDS and VILI may cause irreversible lung damage. Mechanical power measures the amount of energy transferred from the ventilator to the respiratory system and is considered to be a unifying concept of the etiology VILI. However, doubts are still to be clarified. The goals of this study were to analyze pressure-controlled ventilation (PCV) in severe burn injury patients, to associate the mechanical power values over time with the outcome of burn patients (death or survival) and to associate the components of ventilation with the outcome of burn patients. Methods: A longitudinal, observational, and analytical study of 172 measurements of parameters collected daily from the ventilators of 26 severe burn patients undergoing mechanical ventilation with PCV. Statistical analysis was performed on the obtained values and the components of mechanical ventilation in relation to the outcome of the patients. Results: The mechanical power calculated daily in burn patients was 22.83 ± SD joule per minute (J/min). Higher values of mechanical power were significantly related to the mortality (P 0.029) regardless of ventilation time, as well as higher values of PEEP, peak pressure, plateau pressure and driving pressure, (P <0.001), respiratory rate (P 0.01), variation of inspiratory pressure (P 0.03) and lower values of tidal volume (P 0.005). Conclusion: In this analysis of mechanical ventilation, mean values of mechanical power in burn patients were elevated and that, regardless of mechanical ventilation time, these values are related to mortality, as well as higher values of pressures, driving pressure, respiratory rate and lower values of tidal volume, indicating the importance of stress frequency and propulsion force to overcome lung elastance.