Prevention of pneumothorax using venovenous ECMO in acute respiratory distress syndrome with emphysematous/cystic changes in the lung

Introduction

Venovenous extracorporeal membrane oxygenation (VV ECMO) is a treatment option for acute respiratory distress syndrome (ARDS) to minimize ventilator-induced lung injury including life- threatening pneumothorax. The purpose of our study was to investigate the safety and efficacy of VV ECMO for preventing pneumothorax in ARDS patients who were complicated with emphysematous/cystic changes in the lung.

Methods

We have retrospectively analyzed data of ARDS patients complicated with emphysematous/cystic changes in the lung who were admitted to our ICU from 2006 through 2012. We divided the subjects into two groups, patients treated with VV ECMO (ECMO group), and those treated only by conventional ventilator management (non- ECMO group). Correlations between age, sex, underlying disease, PaO₂/ FIO₂ ratio on admission, duration of ICU stay, survival and incidence of pneumothorax were evaluated.

Results

Forty-one patients were included in this study (ECMO and non- ECMO group, 21 and 20 patients, respectively). There were no significant differences between ECMO and non-ECMO groups as regards age, sex, underlying disease, PaO₂/FIO₂ ratio, duration of ICU stay, and survival. In the ECMO group, the mean duration of ECMO use was 17 ± 13 days, and bleeding due to anticoagulation was observed in five patients. The mean airway pressure in the ECMO group was significantly lower than in the non-ECMO group (12 ± 6 cmH₂O, 22 ± 6 cmH₂O, respectively; P < 0.0001). The incidence of pneumothorax was also significantly lower in the ECMO group than the non-ECMO group (10%, 45%, respectively; P = 0.015). In Kaplan-Meier analysis, the proportion of pneumothoraxfree patients was significantly higher in the ECMO group (P = 0.014). In multivariate analysis, conventional ventilator management, presence of interstitial pneumonia and the duration of intubation were the independent risk factors of pneumothorax (hazard ratio (HR), 18.0, P = 0.010; HR 33.3, P = 0.025; HR 1.05, P = 0.041, respectively).

Conclusion

Although the survival rate was not statistically different, the use of ECMO for ARDS patients complicated with emphysematous/ cystic changes in the lung markedly reduced the incidence of pneumothorax.