Médecine pulmonaire et respiratoire

Clara Cell Protein and Surfactant Protein D Plasma Levels are Associated with Clinical Outcomes of Mechanically Ventilated Patients

Abstract

Determann RM, Royakkers AANM, Lutter R, Korevaar JC and Schultz MJ

Background: Plasma levels of Clara cell protein (CC16) and Surfactant Protein D (SP–D) are elevated in patients with Acute Lung Injury or Acute Respiratory Distress Syndrome (ALI/ARDS). We investigated the relation between these biomarkers and clinical outcome scores from mechanically ventilated patients at risk for lung injury.

Methods: Data from all 150 patients enrolled in a previously reported preventive randomized controlled trial, comparing a 10 ml/kg with a 6 ml/kg tidal volume strategy in patients without ALI/ARDS at the onset of mechanical ventilation, were used. CC16 and SP–D levels were measured in plasma samples at baseline and on day 2 and 4 after initiation of the mechanical ventilation protocol. The relation between CC16 and SP–D levels and development of ALI/ARDS (North American European Consensus Conference (NAECC) criteria), and of the following clinical scores: lung injury score, Sequential Organ Failure Assessment (SOFA) score, and oxygenation index, was investigated using multivariate regression analysis.

Results: Plasma CC16 and SP–D levels increased after 4 days in patients who developed acute lung injury (NAECC criteria). At all time points the plasma CC16 level was significantly correlated with the lung injury score, SOFA score and oxygenation index. The highest correlations were observed on day 2 (standardized coefficient, β=0.38; β=0.54; and β=0.40; P<0.001 for all, respectively). The systemic SP–D level was correlated with these scores only on day 4 (β=0.29; β=0.26; and β=0.33; P<0.05 for all, respectively).

Conclusion: Plasma CC16 and SP–D levels may be used to monitor the extent of lung injury in mechanically ventilated intensive care unit patients.