INTRAOPERATIVE VALIDITY OF POINT OF CARE DURING PARTIAL HEPARIN NEUTRALIZATION

Introduction Since 2019, at our Universitary Hospital, an unusual rate of patients had hemostasis abnormalities in immediate postoperative period of cardiac surgery. There was no change in practices explaining these anomalies. In order to assess our professional practices, we conducted a prospective study during one month with complete careful hemostasis monitoring: aPTT, AntiXa activity, Activited Clotting Time (ACT) by Hemostasis Management System (HMS) Plus and Quantra if relevant in the operating room after heparin neutralization. Our analyses frequently showed a defect of heparin antagonization. Indeed, several weeks later, a pharmacovigilance alert indicated a 30% under-dosage of the protamine batches. Therefore, we could evaluate the validity of these monitoring devices with incomplete heparin neutralization. Methods The analysis of coagulation in the operating room was recorded on a collection form. Heparin-induced anticoagulation level and calculation for dose of protamine was tested by the HMS Plus (Medtronic,Minneapolis, MN, USA) device, for all consecutive patients undergoing cardiac surgery. From the same blood sample 15 minutes after the end of protamine infusion, an assay of ACT, aPPT and anti Xa weas performed. In case of unusual clinical bleeding, an additional analysis by Quantra was performed. The study protocol has been submitted and approved by the Ethics Committee of the French Society of Anesthesia and intensive care. Results During the study period, 33 procedures were included, consisting in 26 surgeries with cardiopulmonary bypass and 7 Off-pump coronary artery bypass grafting. Considering a 30% underdosing for protamine, the initial protamine / initial heparin ratio was 0.56 [0.48-0.64]. ACT, APPT and CTR (Quantra) correlated all well with AntiXa activity(Fig). Spearman coefficients were 0.85 [CI: 0.69-0.93] (p 0.5 UI. To detect anti-Xa activity> 0.2, HMS detected residual heparinemia with a sensitivity of 62% [45-78%], a specificity of 94%[50-100%], a positive predictive value of 88% and a negative predictive value of 75%. For ACT, a threshold of 150 sec had a sensitivity of 85% [58-97] and a specificity of 85% [58-97%] for the detection of an antiXa>0.2 UI and a sensitivity of 100% [72-100] and a specificity of 81% [61-93] for the detection of aPTT>100. A threshold of 1.4 CTR had a sensitivity of 67% [30-94] and a specificity of 100% [18-100] for the detection of antiXa activity>0.2 and a sensitivity of 100% [56-100] and a specificity of 100% [61-100] for the detection of aPTT>100. Discussion Despite a limited number of assays, we found that both Quantra and HMS were efficient to detect residual heparinemia in the operating room.