title: Higher mini-BAL total protein concentration in early ARDS predicts faster resolution of lung injury measured by more ventilator-free days.
abstract: The protein concentration of alveolar edema fluid in acute respiratory distress syndrome (ARDS) is dynamic. It reflects alveolar flooding during acute injury, as well as fluid and protein clearance over time. We hypothesized that among ARDS patients treated with low tidal volume ventilation, higher concentrations of protein in mini-bronchoalveolar lavage (mBAL) samples would predict slower resolution of lung injury and worse clinical outcomes. Total protein and IgM concentrations inday 0mBAL samples from 79 subjects enrolled in the aerosolized albuterol (ALTA) ARDS Network Albuterol Trial were measured by colorimetric assay and ELISA, respectively. Linear regression models were used to test the association of mBAL proteins with clinical outcomes and measures of length of illness, including ventilator-free days (VFDs). Median mBAL total protein concentration was 1,740 μg/ml [interquartile range (IQR): 890-3,170]. Each 500 μg/ml increase inday 0mBAL total protein was associated with an additional 0.8 VFDs [95% confidence interval (CI): 0.05-1.6,Pvalue = 0.038]. Median mBAL IgM concentration was 410 ng/ml (IQR: 340-500). Each 50 ng/ml increase in mBAL IgM was associated with an additional 1.1 VFDs (95% CI 0.2-2.1,Pvalue = 0.022). These associations remained significant and were not attenuated in multivariate models adjusted for age, serum protein concentration, and vasopressor use in the 24 h before enrollment. Thus, higher mBAL total protein and IgM concentrations atday 0are associated with more VFDs in patients with ARDS and may identify patients with preserved alveolar epithelial mechanisms for net alveolar fluid clearance.
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California; carolyn.hendrickson@ucsf.edu.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Hendrickson
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.
authors.forename: Jason
authors.initials: J
authors.lastname: Abbott
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.
authors.forename: Hanjing
authors.initials: H
authors.lastname: Zhuo
authors.affiliation: Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.|Department of Anesthesia, University of California, San Francisco; San Francisco, California; and.|Department of Medicine, Division of Nephrology, University of California, San Francisco, San Francisco, California.
authors.forename: Kathleen D
authors.initials: KD
authors.lastname: Liu
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.|Department of Anesthesia, University of California, San Francisco; San Francisco, California; and.
authors.forename: Carolyn S
authors.initials: CS
authors.lastname: Calfee
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco, California.|Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.|Department of Anesthesia, University of California, San Francisco; San Francisco, California; and.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Matthay
mesh_terms: D015415:Biomarkers / Q000097:blood; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism; D016014:Linear Models; D055370:Lung Injury / Q000097:blood / Q000150:complications* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011506:Proteins / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000097:blood / Q000150:complications* / Q000378:metabolism*; D016896:Treatment Outcome; D012122:Ventilators, Mechanical
chemical_list: D015415:Biomarkers; D007075:Immunoglobulin M; D011506:Proteins
keywords: acute respiratory distress syndrome; alveolar fluid clearance; immunoglobulin M; mini-bronchoalveolar lavage