Significant lung injury and its prognostic significance in acute liver failure: A cohort analysis

Background and aims: Respiratory failure complicating acute liver failure (ALF) may preclude liver transplantation (LT). We evaluated the association between significant lung injury (SLI) and important clinical outcomes. Methods: Retrospective cohort study of 947 ALF patients with chest radiograph (CXR) and arterial blood gas (ABG) data enrolled in the US Acute Liver Failure Study Group (US-ALFSG) from January 1998 to December 2016. SLI was defined by moderate hypoxaemia (Berlin classification; PaO₂/FiO₂ < 200 mm Hg) and abnormalities on CXR. Primary outcomes were 21-day transplant-free survival (TFS) and overall survival. Results: Of 947 ALF patients, 370 (39%) had evidence of SLI. ALF patients with SLI (ALF-SLI) had significantly worse oxygenation than controls on admission (median PF ratio 120 vs 300 mm Hg, P <.0001) and higher lactate (6.1 vs 4.6 mmol/l, P =.0008). ALF-SLI patients had higher rates of tracheal (19% vs 14%) and bloodstream (17% vs 11%, P <.005 for both) infections and were more likely to receive transfusions (red cells 55% vs 43%; FFP 74% vs 66%; P <.009 for both). ALF-SLI patients were less likely to receive LT (18% vs 25%, P =.02) and had significantly decreased 21-day TFS (34% vs 42%) and overall survival (49% vs 64%, P <.007 for both). After adjusting for significant covariates (INR, bilirubin, acetaminophen aetiology), the development of SLI was independently associated with decreased 21-day TFS (OR 0.71, P =.03) in ALF patients (C-index 0.78). The incorporation of SLI improved discriminatory ability of the King's College Criteria (P =.0061) but not the ALFSG prognostic index (P =.34). Conclusion: Significant lung injury is a common complication in ALF patients that adversely affects patient outcomes.