End-expiratory lung volumes as a potential indicator for COVID-19 associated acute respiratory distress syndrome: a retrospective study

Abstract

Abstract Background End-expiratory lung volume (EELV) has been observed to decrease in acute respiratory distress syndrome (ARDS). Yet, research investigating EELV in patients with COVID-19 associated ARDS (CARDS) remains limited. It is unclear EELV serve as a potential metric for monitoring disease progression and identifying patients with ARDS at increased risk of adverse outcomes. Study Design and Methods: This retrospective study included mechanically ventilated patients with CARDS during the initial phase of epidemic control in Shanghai. EELV was measured within 48 hours post-intubation, followed by regular assessments every 3–4 days. Chest CT scans, performed within a 24-hour window around each EELV measurement, were analyzed using AI software. Differences in patient demographics, clinical data, respiratory mechanics, EELV, and chest CT findings were assessed using linear mixed models (LMM). Results Out of the 38 enrolled patients, 26.3% survived until discharge from the ICU. In the survivor group, EELV, EELV/PBW and EELV/preFRC were significantly higher than those in the non-survivor group (survivor group vs non-survivor group: EELV: 1455 vs 1162 ml, P = 0.049; EELV/PBW: 24.1 vs 18.5 ml/kg, P = 0.011; EELV/preFRC: 0.45 vs 0.34, P = 0.005). Follow-up assessments showed a sustained elevation of EELV/PBW and EELV/preFRC among the survivors. Additionally, EELV exhibited a positive correlation with total lung volume and residual lung volume, while demonstrating a negative correlation with lesion volume determined through chest CT scans analyzed using AI software. Conclusion EELV is a useful indicator for assessing disease severity and monitoring the prognosis of patients with CARDS.