The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

THE CHARACTERISTIC DIFFERENCE BETWEEN SURVIVORS AND NONSURVIVORS IN ACUTE RESPIRATORY DISTRESS SYNDROME PATIENTS WITH HIGH FREQUENCY OSCILLATORY VENTILATION.

Hui-ching Ting1, Ching-Tzu Huang1, Lan-Ti Chou1, Hsiu-Feng Hsiao1, Chung-Chi Huang2,3, Kuo-Chin Kao2,3; 1Respiratory Therapy, Chang Gung Memorial Hospital, Taoyuan, Taiwan; 2Division of Thoracic Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan; 3Department of Respiratory Care, Chang Gung University, Taoyuan, Taiwan

Background: High frequency oscillatory ventilation (HFOV) is an alternative ventilation mode in acute respiratory distress syndrome (ARDS) patients in whom conventional ventilation (CV) strategies have been failed. The purpose of this study is to analyze the characteristic difference between survivors and nonsurviors in ARDS patients with HFOV. Method: A retrospective case series of 34 adult ARDS patients treated with HFOV were enrolled. The HFOV was applied with severe oxygenation failure (PaO2/FiO2 < 120 mm Hg) despite relatively aggressive CV support (characterized by either PaO2 % 65 mm Hg with FiO2 ^0.6 when PEEP > 10 cm H2O or plateau airway pressure ^ 35 cm H2O). The setting were FiO2 of 0.9 to 1, 5 Hz, inspiratory time of 33%, and a bias flow of 40 L/min. Mean airway pressure (Paw) set 3 to 5 cm H2O greater than the mean Paw during CV. Target oxygenation was SpO2 ^ 90%. If SpO2 was ^ 90%, then FiO2 was reduced stepwise to achieve a target FiO2 %0.6. If SpO2 was < 90%, then mean Paw was increased by 1- 2 cm H2O to a maximum of 45 cm H2O. The pressure amplitude was set to achieve and was adjusted to maintain PaCO2 within 35 and 60 mm Hg with a pH above 7.25. The demographics, baseline, oxygenation and ventilation, hemodynamic and outcome data were recorded. Results: The overall mortality rate was 62% (21/34) in our study group. There was an increase in PaO2/FiO2 ratio after HFOV for 30 minutes and maintained after 20-24 hours of HFOV throughout the study. Table 1 shows the comparison of demographics and baseline parameters between survivors and nonsurvivors. The survivors group had less baseline severity such as lung injury score, organ system failure score, sepsis organ failure assessment and multiple organs dysfunction score than nonsurvivors group. Conventional ventilation time before HFOV was significantly shorter in survivors than nonsurvivors (32.77+/-16.69 vs 47.85+/-26.21 hours, p = 0.049). The duration of HFOV was significantly shorter in survivors than nonsurvivors (35.92+/-21.12 vs 64.95+/-47.13 hours, p = 0.045). Conclusion: High frequency oscillatory ventilation was effective for oxygenation failure in some selected ARDS patients. In this study, the initial less severe ARDS patients had better outcome. The survivors had the shorter conventional ventilation time before HFOV and then shorter HFOV time compared with nonsurvivors. We suggested that HFOV may be applied earlier if clinical indicated. Sponsored Research - None Demographics and characteristics in survivors and non-survivors APACHE II:Acute Physiology and Chronic Health Evaluation II, LIS: lung injury score, OSF: organ system failure, SOFA: sepsis organ failure assessment, MOD: multiple organs dysfunction, OI: oxygenation index, MAP: mean airway pressure, CV: conventional ventilation