# Prognostic value of surfactant protein D and biochemical markers in BALF and plasma of ARDS patients undergoing mechanical ventilation

## TL;DR

This study shows that surfactant protein D levels in lung fluid and blood, along with lactate and pH, can predict survival in ARDS patients on ventilators.

## Contribution

The study demonstrates the prognostic value of SP-D in BALF and plasma for ARDS patients.

## Key findings

- SP-D levels in BALF and plasma were significantly higher in non-survivors.
- Lactate levels were elevated and pH was lower in the death group.
- A combined biomarker model achieved an AUC of 0.883 for predicting 28-day mortality.

## Abstract

Surfactant protein D (SP-D) and circulating exosomes have emerged as potential biochemical indicators of lung injury severity in acute respiratory distress syndrome (ARDS). This study aimed to evaluate the prognostic value of SP-D levels and selected biochemical parameters in bronchoalveolar lavage fluid (BALF) and plasma among ARDS patients receiving mechanical ventilation.

A total of 103 mechanically ventilated ARDS patients were enrolled between February 2020 and February 2023. Patients were classified into survival (n = 59) and death (n=44) groups based on 28-day mortality. On the day of diagnosis, SP-D and exosome levels in BALF and plasma, along with pH, lactate, and oxygenation-related indices, were measured and analyzed for prognostic relevance.

SP-D levels in both BALF and plasma were significantly higher in non-survivors (P < 0.001), while exosome levels did not differ significantly. The death group also showed elevated lactate and lower pH levels (P< 0.05). ROC analysis demonstrated high predictive value for SP-D in BALF (AuC=0.804) and plasma (AU C= 0.864), as well as for lactate and oxygenation indices. A combined biomarker model yielded an AUC of 0.883 for predicting 28-day mortality.

SP-D concentrations in BALF and plasma, along with lactate and acid-base markers, serve as valuable biochemical predictors of short-term prognosis in ARDS patients undergoing mechanical ventilation.