Prognostic value of surfactant proteins A and D in patients with acute lung injury.
OBJECTIVE
The primary objective of this study was to test the hypothesis that in patients intubated for acute lung injury, lower concentrations of surfactant proteins A and D in the pulmonary edema fluid and higher concentrations in the plasma are associated with more severe lung injury and worse clinical outcomes.


METHODS
Observational study.


METHODS
Intensive care unit patients in a tertiary university hospital and a university-affiliated city hospital.


METHODS
Thirty-eight intubated, mechanically ventilated intensive care unit patients with acute lung injury or acute respiratory distress syndrome as defined by the North American European Consensus Conference.


METHODS
Undiluted pulmonary edema fluid and plasma samples were collected within 24 hrs of endotracheal intubation in all patients.


RESULTS
The concentrations of surfactant proteins A and D were measured in pulmonary edema fluid and in plasma. Plasma surfactant protein A, but not surfactant protein D, was higher in patients with fewer days of unassisted ventilation (p = .03) and in patients with an absence of intact alveolar fluid clearance (p =.03). In contrast, pulmonary edema fluid surfactant protein D, but not surfactant protein A, was lower in patients with worse oxygenation, as measured by the alveolar-arterial oxygen difference (p = .01) and was lower in the patients who died (2646 ng/mL) compared with those who survived (5503 ng/mL; p = .02).


CONCLUSIONS
These results demonstrate that reduced pulmonary edema fluid surfactant protein D and elevated plasma surfactant protein A concentrations at the onset of acute lung injury may be associated with more severe disease and worse clinical outcome and may serve as valuable biochemical markers of prognosis.
Cheng
Ivan W
IW
Cardiovascular Research Institute and Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, USA.
Ware
Lorraine B
LB
Greene
Kelly E
KE
Nuckton
Thomas J
TJ
Eisner
Mark D
MD
Matthay
Michael A
MA
D000328:Adult; D015415:Biomarkers; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D011654:Pulmonary Edema / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A / Q000097:blood / Q000378:metabolism*; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000378:metabolism; D018709:Statistics, Nonparametric
D015415:Biomarkers; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D