Extracorporeal membrane oxygenation for life-threatening asthma refractory to mechanical ventilation: analysis of the Extracorporeal Life Support Organization registry

The use of extracorporeal membrane oxygenation (ECMO) in cases of near-fatal asthma (NFA) has increased, but the benefits and potential complications of this therapy have yet to be fully investigated.

Cases were extracted from the Extracorporeal Life Support Organization Registry between March 1992 and March 2016. All patients with a diagnosis of asthma (according to the International Classification of Diseases 9th edition), who also received ECMO, were extracted. Exclusion criteria included patients who underwent multiple courses of ECMO; those who received ECMO for cardiopulmonary resuscitation or cardiac dysfunction; and those with another primary diagnosis, such as sepsis. We analyzed survival to hospital discharge, complications, and clinical factors associated with in-hospital mortality, in patients with severe life-threatening NFA requiring ECMO support.

In total 272 patients were included. The mean time spent on ECMO was 176.4 hours. Ventilator settings, including rate, fraction of inspired oxygen (FiO₂), peak inspiratory pressure (PIP), and mean airway pressure, significantly improved after ECMO initiation (rate (breaths/min), 19.0 vs. 11.3, p < 0.001; FiO₂ (%), 81.2 vs. 48.8, p < 0.001; PIP (cmH₂O), 38.2 vs. 25.0, p < 0.001; mean airway pressure (cmH₂O): 21.4 vs. 14.2, p < 0.001). In particular, driving pressure was significantly decreased after ECMO support (29.5 vs. 16.8 cmH₂O, p < 0.001). The weaning success rate was 86.7%, and the rate of survival to hospital discharge was 83.5%. The total complication rate was 65.1%, with hemorrhagic complications being the most common (28.3%). Other complications included renal (26.8%), cardiovascular (26.1%), mechanical (24.6%), metabolic (22.4%), infection (16.5%), neurologic (4.8%), and limb ischemia (2.6%). Of the hemorrhagic complications, cannulation site hemorrhage was the most common (13.6%). Using multivariate logistic regression analysis, it was found that hemorrhage was associated with increased in-hospital mortality (odds ratio, 2.97; 95% confidence interval, 1.07–8.24; p = 0.036). Hemorrhage-induced death occurred in four patients (1.5%). The most common reason for death was organ failure (37.8%).

ECMO can provide adequate gas exchange and prevent lung injury induced by mechanical ventilation, and may be an effective bridging strategy to avoid aggressive ventilation in refractory NFA. However, careful management is required to avoid complications.