Monocyte programmed death-ligand 1 upregulation in early post-out-of-hospital cardiac arrest is associated with increased risk of acute respiratory distress syndrome.

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a major public health problem. Acute respiratory distress syndrome (ARDS) is a common condition in OHCA patients. We investigated the relationship between the expression of programmed death-1 (PD-1) related molecules and the development and prognosis of ARDS.

METHODS

Between January 2021 and December 2023, post-resuscitated patients were screened for eligibility in the study. PD-1 related molecules expression was measured by flow cytometry at 48 h of admission in patients with OHCA. The prognostic variables were the development of ARDS during hospitalization and the 28-day patient mortality rate. We analyzed the relationship between the expression of PD-1-related molecules and the development of secondary ARDS in OHCA patients, and assessed the correlation of this expression with the prognosis of ARDS patients.

RESULTS

In total, 107 consecutive OHCA patients were enrolled in this study. The median age of the enrolled patients was 60 years, with an age range of 53 to 67 years, and 71 % were male. Among the cardiac arrest patients, 44.8 % had a cardiac etiology, 30.8 % were witnessed, 17.8 % received bystander CPR, and 66.4 % had an initial rhythm of asystole. Our results showed that only monocyte ligand programmed death ligand-1 (PD-L1) expression was significantly elevated in the ARDS group of OHCA patients (P < 0.001). Among patients with ARDS, the expression of PD-L1 on monocytes in non-survivors was significantly higher than in survivors (P < 0.05). The Receiver operating characteristic curves analysis demonstrates that monocyte PD-L1 expression has predictive potential for the development and prognosis of ARDS. Multivariate logistic regression analysis showed that monocyte PD-L1 expression was an independent predictor of mortality in OHCA patients with ARDS.

CONCLUSIONS

This study indicates that patients with increased PD-L1 on monocytes after OHCA may be more likely to develop ARDS. The expression of PD-L1 on monocytes was an independent predictive factor for the incidence of ARDS and mortality rate in OHCA patients.