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 2O). 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 2O (68.0 ± 10.3 vs. 69.7 ± 7.9 mmHg, baseline vs. PEEP 15 cmH 2O; 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 2O; 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 2O vs. 5 cmH 2O, 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 2O. 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.