Significance of Biological Markers in Patients With Acute Lung Injury/Acute Respiratory Disease

BACKGROUND:

Respiratory failure due to ALI and acute respiratory distress syndrome (ARDS) remains a major health problem despite significant progress in intensive care unit (ICU) care and ventilator management. It is also characterized by an unacceptably high mortality rate despite enormous expenditure of health care resources. Survivors of respiratory failure face long-term consequences concerning their quality of life. New therapies are needed to improve early survival and to decrease long-term sequelae of this syndrome. The purpose of this study is to identify biological markers of disease in patients with ALI that are predictive of either disease susceptibility or prognosis, or that identify novel targets of therapeutic intervention.

DESIGN NARRATIVE:

As soon as possible after case identification, informed consent will be obtained from the patient or next of kin. Physiologic measurements and specimen collection will begin at the time of entry into the study. The inclusion criteria for this study allow entry of patients who have fulfilled criteria for ALI/ARDS for up to 48 hours. Bronchoalveolar lavage (BAL) fluid and blood will be collected at various times after the onset of ALI/ARDS in order to measure levels of a predetermined set of biological markers. In addition, DNA will be collected from patients and analysed for the presence of specific genetic polymorphisms that might alter either disease susceptibility or clinical expression of disease. The levels of these markers or the presence of specific genetic polymorphisms will be correlated with measure of pulmonary inflammation and extent of lung injury, as defined by: 1) PaO2/FiO2 ratios; 2) lung compliance; 3) plateau pressures; and 4) calculation of the Murray Lung Injury Score (obtained at entry and Days 1, 2, 3, 5, 7,10, 14, and 21). Secondary outcome measures to be directly correlated with biomarker expression will include indicators of maladaptive responses to ALI (including the development of multiple organ dysfunction syndrome [MODS]), fibroproliferation, and nosocomial pneumonia (events which greatly impact the clinical course of patients with ALI/ARDS). Thus, the secondary outcome measures include: 1) the development of organ failure (using the Sequential Organ Failure Assessment [SOFA] score); 2) time on ventilator; 3) ventilator-free days; 4) ICU and hospital length of stay; 5) hospital mortality; 6) development of pneumonia; 7) development of lung fibrosis (as determined by high-resolution computed tomography [HRCT] and pulmonary function testing); and 8) health related and lung-specific quality of life (as assessed with the Medical Outcome Studies 36-Item Short form Health Survey Standard Form [SF-36] and St. George's Respiratory Questionnaire).