ABSTRACT: The present study aimed to discover potential biomarkers for predicting the prognosis of acute respiratory distress syndrome (ARDS) in conjunction with lung ultrasound (LUS). Blood samples from 112 ARDS patients were collected to compare their partial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2), positive end-expiratory pressure (PEEP), lactic acid, sequential organ failure assessment (SOFA) score, clinical pulmonary infection score (CPIS) and APACHE II score. Kaplan-Meier plots and the log-rank test were performed to analyse the association between the platelet-activating factor acetylhydrolase (PAFAH) G994T polymorphism and the outcome of ARDS regarding mortality. A negative correlation between the LUS score and PaO2/FiO2, PEEP and lactic acid, as well as with the SOFA, CPIS and APACHE II score was confirmed with correlation coefficients of -0.493, -0.548, -0.642, -0.598, -0.566 and -0.567, respectively (all P<0.05). The activity of PAFAH and high-density lipoprotein-PAFAH in the serum collected from subjects of the GG genotype was similar to that in subjects of the GT genotype, but the low-density lipoprotein-PAFAH activity in the serum collected from GG subjects was significantly higher than that in GT subjects. An evident reduction in the PEEP, level of lactic acid, as well as the SOFA, CPIS and APACHE II score was observed in GG subjects, accompanied by a significantly increased PaO2/FiO2. Kaplan-Meier analysis indicated that subjects with a high LUS score had a significantly higher survival rate than those with a low LUS score, and the mortality risk for GG subjects was significantly lower than that for GT subjects. Finally, among all groups (genotype and LUS groups), GG subjects with a high LUS score had the lowest mortality risk, whereas GT subjects with a low LUS score had the highest mortality risk. In addition, the survival rate of GT subjects with a high LUS score was higher than that of GG subjects with a low LUS score. In conclusion, the combination of the LUS score and the G994T polymorphism in exon 9 of the PAFAH gene may be used as a potential prognostic marker for ARDS.