Impact of reductive ventilatory strategies on mechanical power in severely burned patients undergoing pressure-controlled ventilation

Background: Burn patients frequently require invasive mechanical ventilation, often using pressure-controlled ventilation (PCV), and are vulnerable to ventilator-induced lung injury. Mechanical power (MP) has emerged as an integrative measure of ventilatory load and lung stress, and elevated MP is common early in the course of burn-related respiratory failure. Small adjustments in inspiratory pressure variation (ΔPinsp) and RR may influence MP, but their short-term physiological effects under PCV remain unclear. Objective: To compare three MP-reductive ventilatory adjustments (reducing ΔPinsp, RR, or both) to determine which most effectively lowers MP without impairing gas exchange in burn patients receiving PCV. Methods: A randomized short-term physiological study was conducted in 41 burn patients on PCV. Each patient underwent three ventilatory adjustments on consecutive days in a repeated-measures design: a 2 cmH2O reduction in ΔPinsp, a 2 breaths/min reduction in RR, or a combined 1 cmH2O + 1 breath/min reduction. Arterial blood gases and MP were measured at baseline and after 1 h PEEP, FiO2, and inspiratory time remained constant. Results: PaO2 and SaO2 remained stable. PaCO2 increased modestly in all groups without clinically relevant effects. No desaturation, hypoventilation, or asynchrony occurred. All strategies significantly reduced MP, with mean decreases of 4.06 J/min (ΔPinsp), 2.99 J/min (ΔPinsp + RR), and 2.22 J/min (RR), with significant differences across groups (P < 0.001). Conclusion: All three adjustments reduced MP without affecting gas exchange. The greatest reduction occurred with decreasing ΔPinsp, followed by the combined ΔPinsp + RR reduction and RR alone, identifying ΔPinsp reduction as the most effective short-term strategy for lowering MP under PCV.