The fact the that the i-STAT reads higher than the Hemochron leads to the recommendation to validate the methods against each other before changing devices. We conclude that the i-STAT provides a more reliable test for heparin activity and assesses safe anticoagulation during cardiac surgery on pump. We found the i-STAT to systematically return higher measurements. We found that the number of occasions where one of the duplicate readings was >1,000 seconds while the other was below or close to the clinically significant threshold of 400 seconds were higher for the Hemochron.

The within-subject coefficient of variation (WSCV) ranged from 8.2 to 13.6% for the Hemochron and from 4.1 to 9.1% for the i-STAT. The correlation coefficient between two Hemochron and two i-STAT devices was. We analyzed duplicate samples on both devices at all standard measuring points during the procedure. We included 402 patients from three institutions (Papworth Hospital, Cambridge, UK Groote Schuur, Cape Town, South Africa University Hospital Basel, Basel, Switzerland) undergoing elective cardiac surgery on CPB in our study.

We compared two different methods of measuring the ACT: i-STAT, which uses amperometric detection of thrombin cleavage, and Hemochron Jr, which is based on detecting viscoelastic changes in blood. Since over 30 years, the activated clotting time (ACT) has been used to assess the level of heparin activity both before and after CPB. Unfractionated heparin is the mainstay of anticoagulation during cardiac surgery on cardiopulmonary bypass (CPB) due to its low cost, quick onset, and ease of reversal.

Istat electronic simulator