Lung ultrasound to evaluate aeration changes in response to recruitment maneuver and prone positioning in intubated patients with COVID-19 pneumonia: preliminary study

BACKGROUND: This single-center preliminary prospective observational study used bedside ultrasound to assess the lung aeration modifications induced by recruitment maneuver and pronation in intubated patients with acute respiratory disease syndrome (ARDS) related to coronavirus 2019 disease (COVID-19). All adult intubated COVID-19 patients suitable for pronation were screened. After enrollment, patients underwent 1 h in a volume-controlled mode in supine position (baseline) followed by a 35-cmH(2)O-recruitment maneuver of 2 min (recruitment). Final step involved volume-controlled mode in prone position set as at baseline (pronation). At the end of the first two steps and 1 h after pronation, a lung ultrasound was performed, and global and regional lung ultrasound score (LUS) were analyzed. Data sets are presented as a median and 25th–75th percentile. RESULTS: From January to May 2022, 20 patients were included and analyzed. Global LUS reduced from 26.5 (23.5–30.0) at baseline to 21.5 (18.0–23.3) and 23.0 (21.0–26.3) at recruitment (p < 0.001) and pronation (p = 0.004). In the anterior lung regions, the regional LUS were 1.8 (1.1–2.0) following recruitment and 2.0 (1.6–2.2) in the supine (p = 0.008) and 2.0 (1.8–2.3) in prone position (p = 0.023). Regional LUS diminished from 2.3 (2.0–2.5) in supine to 2.0 (1.8–2.0) with recruitment in the lateral lung zones (p = 0.036). Finally, in the posterior lung units, regional LUS improved from 2.5 (2.3–2.8) in supine to 2.3 (1.8–2.5) through recruitment (p = 0.003) and 1.8 (1.3–2.2) with pronation (p < 0.0001). CONCLUSIONS: In our investigation, recruitment maneuver and prone positioning demonstrated an enhancement in lung aeration when compared to supine position, as assessed by bedside lung ultrasound. Trial registration: www.clinicaltrials.gov, Number NCT05209477, prospectively registered and released on 01/26/2022.