Open Access 01-04-2013 | Research
Physiological predictors of survival during high-frequency oscillatory ventilation inadults with acute respiratory distress syndrome
Published in: Critical Care | Issue 2/2013
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Introduction
Data that provide clinical criteria for the identification of patients likely torespond to high-frequency oscillatory ventilation (HFOV) are scarce. Our aim wasto describe physiological predictors of survival during HFOV in adults with severeacute respiratory distress syndrome (ARDS) admitted to a respiratory failurecenter in the United Kingdom.
Methods
Electronic records of 102 adults treated with HFOV were reviewed retrospectively.We used logistic regression and receiving-operator characteristics curve to testassociations with oxygenation and mortality.
Results
Patients had severe ARDS with a mean (SD) Murray's score of 2.98 (0.7). Partialpressure of oxygen in arterial blood to fraction of inspired oxygen(PaO2/FiO2) ratio and oxygenation index improved only insurvivors. The earliest time point at which the two groups differed was at threehours after commencing HFOV. An improvement of >38% inPaO2/FiO2 occurring at any time within the first 72hours, was the best predictor of survival at 30 days (area under the curve (AUC)of 0.83, sensitivity 93%, specificity 78% and a positive likelihood ratio (LR) of4.3). These patients also had a 3.5 fold greater reduction in partial pressure ofcarbon dioxide in arterial blood (PaCO2). Multivariate analysis showedthat HFOV was more effective in younger patients, when instituted early, and inpatients with milder respiratory acidosis.
Conclusions
HFOV is effective in improving oxygenation in adults with ARDS, particularly wheninstituted early. Changes in PaO2/FiO2 during the firstthree hours of HFOV can identify those patients more likely to survive.