Background: Mechanical power (MP) is a promising tool for guidance of lung protective ventilation. Different equations have been proposed to calculate MP in pressure control ventilation (PCV). The aim of this study is to introduce an easy to use MP equation MP<inf>pcv(m-simpl)</inf> and compare it to an equation proposed by Van der Meijden et al. (MP<inf>pcv</inf>) which considered as the reference equation in PCV.
Methods: Ventilatory parameters of 206 Covid-19 ARDS patients recorded between 24-72 hours after admission to intensive care unit. The PCV data from these patients were retrospectively investigated. MP in PCV was calculated with a modified equation (MP<inf>pcv(m-simpl)</inf>) derived from the equation (MP<inf>pcv</inf>) of Van der Meijden et al.: 0.098xRRx∆Vx(PEEP+∆P<inf>insp</inf> - 1). The results from MP<inf>pcv(slope)</inf>, MP<inf>pcv(simpl)</inf>, and<inf> </inf>MP<inf>pcv(m-simpl) </inf>were compared to MP<inf>pcv</inf> at 15 cmH<inf>2</inf>O ∙ s/L inspiratory resistance levels by univariable regression and Bland-Altman analysis.
Results: Inspiratory resistance levels at 15 cmH<inf>2</inf>O s/L was found to be correlated between the power values calculated by MP<inf>pcv(simpl)</inf>/MP<inf>pcv(m-simpl)</inf> and the MP<inf>pcv(slope)</inf>/MP<inf>pcv</inf> based on univariable logistic regression (R2≥98) analyses. In the comparison of all patients average MP values computed by the MP<inf>pcv(m-simpl)</inf> equation and the MP<inf>pcv</inf> reference equation. Bland-Altman analysis mean difference and p values at 15 cmH<inf>2</inf>O s/L inspiratory resistance values (J/min) were found to be MP<inf>pcv(m-simpl)</inf> vs MP<inf>pcv</inf>=-0,04 (P=0.014); MP<inf>pcv(slope)</inf> vs. MP<inf>pcv</inf>=0.63 (P<0.0001); MP<inf>pcv(simpl)</inf> vs. MP<inf>pcv</inf>=0.64 J/min (P<0.0001), respectively.
Conclusions: The results of this study confirmed that the MP<inf>pcv(m-simpl)</inf> equation can be used easily to calculate MP at bedside in pressure control ventilated COVID-19 ARDS patients.