Comparison of mechanical power estimations in mechanically ventilated patients with ARDS: a secondary data analysis from
- PDF / 621,855 Bytes
- 3 Pages / 595.276 x 790.866 pts Page_size
- 64 Downloads / 225 Views
LETTER
Comparison of mechanical power estimations in mechanically ventilated patients with ARDS: a secondary data analysis from the EPVent study Maximilian S. Schaefer1,2* , Stephen H. Loring1, Daniel Talmor1 and Elias N. Baedorf‑Kassis3 © 2020 Springer-Verlag GmbH Germany, part of Springer Nature
Dear Editor, Our understanding of lung injury in mechanically ventilated patients has been expanded by the concept of mechanical power, a calculation integrating strain (tidal volume), stress (pressure) and the rate of lung deformation [1]. Mechanical power estimates energy applied to the respiratory system per minute, which has been associated with mortality [2]. However, the components from which to calculate mechanical power remain controversial: animal studies suggested including positive end-expiratory pressure (PEEP) into the calculation [1, 3], but clinical data point towards driving pressure as a key variable for VILI [4]. Calculations from airway pressure (Pao), here termed Respiratory System (RS)-directed Power (Fig. 1A, B), include work to overcome the elastic recoil of the chest wall and do not account for spontaneous breathing. Alternative estimations of mechanical power might address these limitations: RS-directed Driving Power excludes PEEP and isolates “dynamic” power (Fig. 1C, D). With transpulmonary pressure (PL) measurements, Lung-directed Driving Power (Fig. 1E, F) can be calculated, isolating power applied to the lung and accounting for spontaneous breathing. We conducted secondary analyses of flow/pressure recordings from 53 patients in the EPVent study [5], comparing these three estimates in patients with the *Correspondence: [email protected] 1 Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA Full author information is available at the end of the article
acute respiratory distress syndrome. Mechanical power was calculated from 4,803 breathing cycles as the area between the inspiratory limb of the pressure and the volume (electronic supplementary material). At a median PEEP of 13.1 [IQR 10.6; 16.6] cmH2O, RS-directed Power was 37.2 [24.1; 51.4] J*min−1 compared to 14.2 [11; 19.8] J*min−1 for RS-directed Driving Power and 13.4 [9.9; 18.8] J*min−1 for Lung-directed Driving Power, p
Data Loading...
