A simple method of mechanical power calculation: using mean airway pressure to replace plateau pressure.

The reference method for mechanical power (MP) calculation proposed by Gattinoni et al. is based on plateau pressure (P) which needs an inspiratory hold. This study aims to introduce and validate a simple surrogate for MP calculation without any intervention in ventilated patients with or without acute respiratory distress syndrome (ARDS). The introduced equation is as:[Formula: see text]where P is mean airway pressure, VE is minute ventilation, PEEP is positive end-expiratory pressure, and T/T is expiratory-to-inspiratory ratio. 50 patients with ARDS and 50 post-operative patients without ARDS were enrolled. P-derived MP and reference MP were obtained at the inspiratory plateau time (T) of 0 and 0.5 s (s). When T was adjusted from 0 to 0.5 s, higher P [non-ARDS cases: 9.3 (8.8-9.9) cmHO versus 8.2 (7.9-8.8) cmHO, P < 0.001; ARDS cases: 14 (13-16) cmHO versus 13 (11-14) cmHO, P < 0.001] and shorter T/T [non-ARDS cases: 1.4 (1.2-1.7) versus 2.4 (2.0-3.0), P < 0.001; ARDS cases: 1.3 (1.2-1.5) versus 2.5 (2.3-2.9), P < 0.001] were found. At both T levels, the P-derived MP correlated well with the reference MP both in patients with or without ARDS (non-ARDS: slopes = 1.05, 0.94, R = 0.95, 0.93, bias + 0.76, + 0.51; ARDS: slopes = 1.03, 0.95, R = 0.96, 0.96, bias + 0.97, + 0.78. P < 0.0001 for all). In patients with or without ARDS, P-derived MP allows rapid and dynamic estimation of mechanical power without any intervention at the bedside.