The U.S. FDA has released the special controls needed for extracorporeal carbon dioxide removal thanks to the successful pursuit of a de novo petition by Pittsburgh-based Alung Technologies Inc., but generating the clinical data for successor 510(k) devices will be no mean feat. While some of the associated in vivo testing may be performed on animal models, the list is extensive and includes testing for hemodynamic instability and inadequate gas exchange, all reasons that Alung and the FDA needed the better part of a decade to bring this device to the U.S. market.