Difference of Short Term Survival in Patients with ARDS According to Responsiveness to Alveolar Recruitment

Kim, Ho Cheol; Cho, Dae Hyun; Kang, Gyoung Woo; Park, Dong Jun; Lee, Jong Deok; Hwang, Young Sil

Abstract

BACKGROUND: Lung protective strategies, using low tidal volume in ARDS, improve survival rate in ARDS. However, low tidal volume ventilation may promote alveolar de-recruitment. Therefore, alveolar recruitment is necessary to maintain arterial oxygenation and to prevent repetitive opening and closure of collapsed alveoli in lung protective strategies. There has been a recent report describing improvement in arterial oxygenation with use of recruitment maneuver. However, impact of recruitment on outcome of ARDS is unknown. We evaluated whether short-term survival difference existed in patients with ARDS, who were performed alveolar recruitment maneuver(ARM) and prone position, according to response of alveolar recruitment or not.
METHODS
All patients who were diagnosed with ADRS and received mechanical ventilation were included. ARM were sustained inflation(35-45 cmH2O CPAP for 30-40 sec.) or increasing level of PEEP. If these methods were ineffective, alveolar recruitment with prone position was done for at least 10 hours. PaO2/FiO2(P/F) ratio was determined before and at 0.5 and 2 hours after ARM. We defined a responder if the P/F ratio was increased over 50% of baseline value. We compared 10-days and 30-days survival rate between responders and non-responders.
RESULTS
20 patients(M:F=12:8, 63 +/- 14 age) were included. Among them, 12 patients were responders and 8 patients were non-responders. In responders, P/F ratio was increased from 92 +/- 25 mmHg to 244 +/- 85 mmHg. In non-responders, P/F ratio increased from 138 +/- 37 mmHg to 163 +/- 60 mmHg. Among non-responders, P/F ratio was improved over 50% in 2 patients after prone position. Overall, 14 patients were responders after ARM and prone position. The 10-days and 30-days survival rate in responders was significantly higher than in non-responders(86%, 57% in responders and 33%, 0% in non-responders)(p<0.05). There was no significant difference between responders and non-responders in age(71 +/- 11, 60 +/- 14), lung injury score(2.8 +/- 0.2, 2.9 +/- 0.45), simplified acute physiology score(SAPS) II (35 +/- 4.6, 34 +/- 5.7), positive end-positive pressure level(15.6 +/- 1.9 cmH2O, 14.5 +/- 2.1 cmH2O).
CONCLUSION
ARM may improve arterial oxygenation in some patients with ARDS. These responders in patients with ARDS showed significant higher 10-days and 30-days survival rate than non-responders patients with alveolar recruitment.