Mechanical power and 30-day mortality in mechanically ventilated, critically ill patients with and without Coronavirus Disease-2019: a hospital registry study

Abstract

Background Previous studies linked a high intensity of ventilation, measured as mechanical power, to mortality in patients suffering from “classic” ARDS. By contrast, mechanically ventilated patients with a diagnosis of COVID-19 may present with intact pulmonary mechanics while undergoing mechanical ventilation for longer periods of time. We investigated whether an association between higher mechanical power and mortality is modified by a diagnosis of COVID-19. Methods This retrospective study included critically ill, adult patients who were mechanically ventilated for at least 24 h between March 2020 and December 2021 at a tertiary healthcare facility in Boston, Massachusetts. The primary exposure was median mechanical power during the first 24 h of mechanical ventilation, calculated using a previously validated formula. The primary outcome was 30-day mortality. As co-primary analysis, we investigated whether a diagnosis of COVID-19 modified the primary association. We further investigated the association between mechanical power and days being alive and ventilator free and effect modification of this by a diagnosis of COVID-19. Multivariable logistic regression, effect modification and negative binomial regression analyses adjusted for baseline patient characteristics, severity of disease and in-hospital factors, were applied. Results 1,737 mechanically ventilated patients were included, 411 (23.7%) suffered from COVID-19. 509 (29.3%) died within 30 days. The median mechanical power during the first 24 h of ventilation was 19.3 [14.6–24.0] J/min in patients with and 13.2 [10.2–18.0] J/min in patients without COVID-19. A higher mechanical power was associated with 30-day mortality (ORadj 1.26 per 1-SD, 7.1J/min increase; 95% CI 1.09–1.46; p = 0.002). Effect modification and interaction analysis did not support that this association was modified by a diagnosis of COVID-19 (95% CI, 0.81–1.38; p-for-interaction = 0.68). A higher mechanical power was associated with a lower number of days alive and ventilator free until day 28 (IRRadj 0.83 per 7.1 J/min increase; 95% CI 0.75–0.91; p < 0.001, adjusted risk difference − 2.7 days per 7.1J/min increase; 95% CI − 4.1 to − 1.3). Conclusion A higher mechanical power is associated with elevated 30-day mortality. While patients with COVID-19 received mechanical ventilation with higher mechanical power, this association was independent of a concomitant diagnosis of COVID-19.

Impact of mechanical power on mortality in ventilated critically ill patients. Retrospective study with continuous real-life data

“…Most MP studies with different outcomes included patients with ARDS [20][21][22] and a strong association between MP and mortality was observed. This association has also been observed in patients without ARDS [24][25][26][27] , and recently in patients with COVID-19 23,27 . Our results in the sub-analyses of patients with COVID-19 suggest that MP maintains a close relationship with mortality, although the contribution to IMV days appears to be lower than in non-COVID-19 patients.…”

“…Given that IMV is a continuous process that can result in VILI at any point during IMV, it is logical to expect that the amount of time the lung is exposed to a MP above the safe cut-off point will result in an increased risk of VILI 37,38 . MP data from the rst hours or days of IMV and with spot measurements throughout the day should be interpreted with caution [21][22][23][24][25][26][27]36 . Similar works have been carried out by Serpa et al in 2018 24 and Zhu et al in 2021 25 with data from the MIMIC III an e-ICU database.…”

“…Despite the aforementioned studies [20][21][22][23][24][25][26][27] , the safe threshold of MP and whether MP should be considered a target in IMV or only an expression of the severity of the underlying lung damage remains unclear. More importantly, previous studies [20][21][22][23][24][25][26][27] consider single time-point MP measurements without taking into account intra-patient variations over time, which limits their conclusions.…”

The Impact of Mechanical Energy Assessment on Mechanical Ventilation: A Comprehensive Review and Practical Application

“…A similar study evaluating Vt based on ideal body weight found that even after normalization to the predicted body weight, the same Vt can generate different lung strains and different lung damage based on individual lung conditions [ 38 ]. A retrospective analysis of MP in COVID-19 (coronavirus disease 2019) and non-COVID-19 ARDS patients was performed in 1737 patients with almost 30% mortality [ 39 ]. The median MP during the first 24 h of ventilation was 19.3 [14.6–24.0] J/min in patients with and 13.2 [10.2–18.0] J/min in patients without COVID-19, and higher MP was associated with increased mortality independent of COVID-19.…”

Machine learning model for predicting immediate postoperative desaturation using spirometry signal data

“…AWP and volume form a spirometry loop, providing information regarding lung mechanics. In addition, previous studies reported that mechanical power was associated with ventilator-related lung injury 17 – 19 . AWP and VOL both play an important role in calculating mechanical power 20 .…”