Has anyone else been experiencing difficulty de-airing the Quadrox-iD? We have had 4 instances where we were either unable to de-air, or extreme difficulty de-airing the pre-membrane side. We have seen an air bubble as big as a quarter in 1, and then the others were full of champagne bubbles. It has occurred with both the BioLine and the SoftLine within the past 1-2 months. We have been using these oxygenators for our ECMO circuit for over 6 years, and have never had an issue until recently.