Experience and results with VV-ECMO for severe acute respiratory failure: weaning vs. non-weaning.

In a retrospective review of 45 cases where patients were placed on VV ECMO, investigators from Seoul performed a multivariate analysis of pre-ECMO risk factors  that might be predictive of  an unsuccessful ECMO wean.  Notably, successful weaning from ECMO was only 46%, and overall survival was only 18%.   Importantly, higher platelet counts at ICU admission and the day prior to initiating ECMO were predictive of successful weaning.  Specifically, patients with a platelet count > 70K had an 11X greater likelihood of a successful wean.  Why?  Is the low platelet count a surrogate for the severity of illness?