Morphological subphenotypes of acute pancreatitis-related acute respiratory distress syndrome

BACKGROUND: Acute Respiratory Distress Syndrome (ARDS) encompasses heterogenous subphenotypes. We assessed whether morphological subphenotypes of Acute Pancreatitis-related ARDS have differential responses to prone position and positive end-expiratory pressure (PEEP). METHODS: We analyzed a retrospective cohort of all consecutive critically ill adults with Acute Pancreatitis-related ARDS and early CT-scan admitted to ICU from 2003 to 2023. ARDS was classified according to CT-scan as “Focal ARDS” or “Non-Focal ARDS.” The primary outcome was 90-day mortality. Treatment effects for prone position and high PEEP were assessed. Adjusted Hazard Ratios (aHR) were calculated with a multivariate Cox analysis. Machine-learning models were developed with XGBoost and explained with SHAP. RESULTS: Among the 5,865 patients screened, 151 Acute Pancreatitis-related ARDS were included in the analysis. Eighty-one patients (54%) were classified as Focal ARDS and 70 patients (46%) as Non-Focal ARDS. There was no significant difference in ARDS management. The overall 90-day mortality was of 37% (56/151). There was no significant difference in 90-day mortality between Focal and Non-Focal ARDS (33/81 [41%] vs 33/70 [34%], adjusted Hazard Ratio (aHR): 1.01 [0.58–1.76], p = 0.98). Prone position was associated with lower 90-day mortality in Focal ARDS (aHR: 0.25 [0.08 – 0.76], p = 0.015) but not in Non-Focal ARDS. High PEEP was associated with lower 90-day mortality in Non-Focal ARDS (aHR: 0.22 [0.06–0.85], p = 0.029) but not in Focal ARDS. Machin-learning models concurred with differential responses to prone position and PEEP. CONCLUSION: Two morphological subphenotypes of Acute Pancreatitis–related ARDS were identified and were evenly distributed. Although their clinical characteristics and outcomes were comparable, they exhibited treatment-specific responses: prone positioning was associated with lower mortality in Focal ARDS, whereas high PEEP was associated with lower mortality in Non-Focal ARDS. These findings suggest that morphology may help guide personalized ventilatory strategies in this specific ARDS population.