Lung Recruitment, Individualized PEEP, and Prone Position Ventilation for COVID-19-Associated Severe ARDS: A Single Center Observational Study

Background: Patients with coronavirus disease 2019 (COVID-19) may develop severe acute respiratory distress syndrome (ARDS) The aim of the study was to explore the lung recruitability, individualized positive end-expiratory pressure (PEEP), and prone position in COVID-19-associated severe ARDS Methods: Twenty patients who met the inclusion criteria were studied retrospectively (PaO(2)/FiO(2) 68 0 ± 10 3 mmHg) The patients were ventilated under volume-controlled mode with tidal volume of 6 mL/kg predicted body weight The lung recruitability was assessed via the improvement of PaO(2), PaCO(2), and static respiratory system compliance (C(stat)) from low to high PEEP (5-15 cmH(2)O) Patients were considered recruitable if two out of three parameters improved Subsequently, PEEP was titrated according to the best C(stat) The patients were turned to prone position for further 18-20 h Results: For recruitability assessment, average value of PaO(2) was slightly improved at PEEP 15 cmH(2)O (68 0 ± 10 3 vs 69 7 ± 7 9 mmHg, baseline vs PEEP 15 cmH(2)O;p = 0 31) However, both PaCO(2) and C(stat) worsened (PaCO(2): 72 5 ± 7 1 vs 75 1 ± 9 0 mmHg;p < 0 01 C(stat): 17 5 ± 3 5 vs 16 6 ± 3 9 ml/cmH(2)O;p = 0 05) Only four patients (20%) were considered lung recruitable Individually titrated PEEP was higher than the baseline PEEP (8 0 ± 2 1 cmH(2)O vs 5 cmH(2)O, p < 0 001) After 18-20 h of prone positioning, investigated parameters were significantly improved compared to the baseline (PaO(2): 82 4 ± 15 5 mmHg PaCO(2): 67 2 ± 6 4 mmHg C(stat): 20 6 ± 4 4 ml/cmH(2)O All p < 0 001 vs baseline) Conclusions: Lung recruitability was very low in COVID-19-associated severe ARDS Individually titrated PEEP and prone positioning might improve lung mechanics and blood gasses