2006 OPEN FORUM Abstracts
Early Oxygenation Index Improvement is Associated with Favorable Outcome of Acute Respiratory Distress Syndrome in Adults Receiving High Frequency Oscillatory Ventilation
Chun-Cheih Yang MD, John
D. Davies RRT FAARC, Yuh-Chin
T. Huang MD, Michael A. Gentile RRT
FAARC, Ira M. Cheifetz MD FAARC, Neil R. MacIntyre MD, FAARC Duke University Medical Center Durham, NC
Background: Patients with acute respiratory distress syndrome (ARDS) often require escalating ventilatory support such as high-frequency oscillatory ventilation (HFOV). The purpose of this study is to evaluate the association of 30-day mortality and the average oxygenation index (OI) (mPaw × FiO2/PaO2) change between the 12th hour and 24th hour after initiation of HFOV in adults with ARDS.
Methods: We retrospectively reviewed ARDS patients managed with HFOV from March, 2001 to October, 2005.
Results: 75 adult patients with ARDS were treated with HFOV. All 75 patients had severe ARDS as evidenced by a pre-HFOV mean PaO2 / FiO2 ratio of 84 ± 27 mmHg, and an OI of 27.7 ± 12.9. The most common etiology of ARDS was pneumonia (44 patients). The mean (± SD) APACHE II score was 23.9 ± 6.1. The mean duration of conventional ventilation prior to HFOV was 4.2 ± 5.5 days. The 30-day mortality rate was 25.3%. The OI change (baseline OI - OI at 12-24 hours post-HFOV) was the only significant index between survivors and non-survivors (p = 0.002). Based on the receiver operating characteristic (ROC) curve, the OI change of ≥ 0.035 had specificity, sensitivity, positive predictive value and negative predictive value of 74%, 68%, 88% and 44%, respectively for predicting survival.
Conclusions: Improvement in OI from 12 to 24 hours after initiation of HFOV is associated with better survival. Monitoring OI during the first day of HFOV may identify a subgroup of patients who mostly likely would benefit from HFOV.