Low PEEP Mechanical Ventilation and PaO(2)/FiO(2) Ratio Evolution in COVID-19 Patients

Ceruti, Samuele; Roncador, Marco; Saporito, Andrea; Biggiogero, Maira; Glotta, Andrea; Maida, Pier Andrea; Urso, Patrizia; Bona, Giovanni; Garzoni, Christian; Mauri, Romano; Borgeat, Alain

Invasive mechanical ventilation (IMV) is the standard treatment in critically ill COVID-19 patients with acute severe respiratory distress syndrome (ARDS). When IMV setting is extremely aggressive, especially through the application of high positive-end-expiratory respiration (PEEP) values, lung damage can occur. Until today, in COVID-19 patients, two types of ARDS were identified (L- and H-type); for the L-type, a lower PEEP strategy was supposed to be preferred, but data are still missing. The aim of this study was to evaluate if a clinical management with lower PEEP values in critically ill L-type COVID-19 patients was safe and efficient in comparison to usual standard of care. A retrospective analysis was conducted on consecutive patients with COVID-19 ARDS admitted to the ICU and treated with IMV. Patients were treated with a lower PEEP strategy adapted to BMI: PEEP 10 cmH(2)O if BMI < 30 kg m(−2), PEEP 12 cmH(2)O if BMI 30–50 kg m(−2), PEEP 15 cmH(2)O if BMI > 50 kg m(−2). Primary endpoint was the PaO(2)/FiO(2) ratio evolution during the first 3 IMV days; secondary endpoints were to analyze ICU length of stay (LOS) and IMV length. From March 2 to January 15, 2021, 79 patients underwent IMV. Average applied PEEP was 11 ± 2.9 cmH(2)O for BMI < 30 kg m(−2) and 16 ± 3.18 cmH(2)O for BMI > 30 kg m(−2). During the first 24 h of IMV, patients’ PaO(2)/FiO(2) ratio presented an improvement (p<0.001; CI 99%) that continued daily up to 72 h (p<0.001; CI 99%). Median ICU LOS was 15 days (10–28); median duration of IMV was 12 days (8–26). The ICU mortality rate was 31.6%. Lower PEEP strategy treatment in L-type COVID-19 ARDS resulted in a PaO(2)/FiO(2) ratio persistent daily improvement during the first 72 h of IMV. A lower PEEP strategy could be beneficial in the first phase of ARDS in critically ill COVID-19 patients.