Maintaining the standard: a quality assurance study for new equipment in the Michigan ECMO Program

Activated clotting time (ACT) ranges are targeted to minimize both bleeding and clotting complications during anticoagulation for extracorporeal life support (ECLS) therapy. A change in the equipment used to measure ACT at the bedside prompted a laboratory-based method comparison study in an animal model to compare ACT results from two Hemochron machines. A retrospective, observational cohort study was undertaken to compare bleeding and clotting complications for both "eras" of Hemochron machine. The newer Hemochron Response ACT results were approximately 30 seconds longer than the outgoing Hemochron 401 results at both baseline and heparinization. This prompted a change in the clinical practice standard at the University of Michigan and a shift of the goal ACT range from 180 to 200 seconds to 210 to 230 seconds. Bleeding and clotting complications were less frequent in the Hemochron Response group, although significantly more heparin was infused during the ECLS period. Changes in equipment, which measure important physiologic variables at the bedside, need to be compared with previously established standards to ensure that patient care and safety is maintained, as demonstrated by the longer ACT results obtained with the newer Hemochron Response machine.