To analyze the predictive value of the lung injury prediction score (LIPS) and angiopoietin-2 (Ang-2) for the development of acute respiratory distress syndrome (ARDS) in patients with pulmonary infection.

A total of 90 patients with pulmonary infection who were admitted to the Respiratory Intensive Care Unit (RICU) and Emergency Intensive Care Unit (EICU) of the Second, First, and Third Affiliated Hospitals of Army Medical University between March 2013 and May 2022 were enrolled. Thirty-one patients who developed ARDS within one week were assigned to the observation group, and fifty-nine patients who did not develop ARDS were assigned to the control group. Clinical data were collected from both groups, including age, sex, smoking and drinking history, comorbidities (hypertension, diabetes, coronary heart disease), underlying respiratory diseases(chronic obstructive pulmonary disease and bronchiectasis), oxygenation index, APACHE Ⅱ score, LIPS score, ARDS incidence, and the expression levels of four biomarkers. Receiver operating characteristic (ROC) curves were plotted to evaluate and compare the predictive value of LIPS, Ang-2, and their combination for ARDS in patients with pulmonary infection.

The oxygenation index in the observation group was lower than that in the control group [(167.88±74.99)mmHg vs. (265.94±96.91) mmHg, P<0.05]. Fourteen patients (45.16%) died in the observation group compared with eight patients (13.56%) in the control group, with a significantly higher mortality in the observation group (P<0.05). The observation group also had higher APACHE Ⅱ scores (19.68±7.69 vs. 15.81 ±6.25), higher LIPS scores [6.50(5.50~7.50) vs. 3.50(2.50~5.50)], higher Ang-2 levels [6.01(2.50~12.32) vs. 1.64(0.75~3.29)ng/ml], and higher IL-8 levels [54.43(3.9~118.11) vs. 3.91(3.91~44.78)pg/ml], with statistically significant differences (P<0.05). Multivariate logistic regression analysis showed that LIPS and Ang-2 were independent risk factors for ARDS in patients with pulmonary infection (P<0.05). Both LIPS and Ang-2 had predictive value for ARDS, with no significant difference between the two (AUROC: 0.82 vs. 0.77, P=0.518). The combined use of LIPS and Ang-2 achieved a higher area under the curve (AUC=0.90, 95%CI: 0.82~0.96, P=0.000), which was significantly greater than that of either LIPS or Ang-2 alone (Z=2.65, P=0.008; Z=2.44, P=0.015, respectively). The combined model yielded a positive predictive value of 76.46%.

LIPS and Ang-2 can serve as predictive indicators for ARDS in patients with pulmonary infection. The combined application of LIPS and Ang-2 provides a identification of high-risk patients for developing ARDS.