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Nonlinear analysis of breathing patterns in development of acute and chronic lung injury
Author(s) -
Palacios Mariana Yvonne,
Jacono Frank J.,
Ceco Ermelinda,
Fishman Mikkel,
Loparo Kenneth A,
Dick Thomas E
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.756.13
Subject(s) - medicine , sample entropy , plethysmograph , expiration , lung , breathing , cardiology , anesthesia , respiratory system , mathematics , statistics , time series
Objective: Determine whether nonlinear analysis can identify breathing pattern trends that are indicative of the progression and outcome of acute lung injury (ALI). Methods: Male Sprague‐Dawley rats (n=10) received intratracheal instillation of either bleomycin (3–4 units/120–160μL PBS) or PBS (160μL). Baseline breathing was recorded in unanesthetized animals using whole‐body plethysmography every other day after surgery. Multiple epochs (600‐s) were selected and breath‐to‐breath variability of expiration (T e ) was assessed systematically by linear (mean, coefficient of variation) and nonlinear (mutual information, sample entropy of intervals and successive differences) tools. At two weeks, lung collagen content was measured. Results: Linear analysis did not discriminate the severity or outcome of injury. In contrast, nonlinear methods showed a trend between decreased average entropy of successive differences of T e across time lags and acute injury. The increase in entropy of breath‐to‐breath magnitude changes of T e across time lags was significantly greater for the animals with fulminant injury compared to resolving injury. Lung collagen content was not different between groups. Conclusion: Nonlinear analysis identified subtle changes in breathing variability, indistinguishable by linear analysis, that correlate to injury acuity prior to development of fibrosis ( HL080138 , VA Research Service & T35 NHLBI Summer Research Program).