Reappearance of Circulating Heparin in Whole Blood Heparin Concentration-Based Management Does Not Correlate With Postoperative Bleeding After Cardiac Surgery

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

“…Therefore, a 1 : 1 ratio between primary heparin dose and protamine dose cannot be recommended. Here, a heparin to protamine ratio of 1 : 0.6-0.8 seems to be more effective [56,61,62]. Additional protamine administration is definitively not beneficial in patients with a prolonged ACT due to a protamine overdose.…”

“…Ichikawa et al [56] reported a very weak correlation between ACT (r = 0.12) as well as activated partial thromboplastin time (APTT) (r = 0.36) and the heparin concentration determined by the anti-Xa activity. In contrast, the CT IN /CT HEP -ratio correlated well (r = 0.72) with the anti-Xa activity.…”

Anticoagulant and side-effects of protamine in cardiac surgery: a narrative review

“…It was recently shown that heparin rebound might be of less importance as cause for postoperative bleeding than previously assumed, showing no correlation between postprotamine heparin concentrations and the total volume of blood loss (r¼0.35; P¼0.106). 117 Others showed that different protamine-to-heparin dosing ratios ranging from 1.1 to 0.8 are associated with similar incidences of heparin rebound. 110 Additionally, we showed that post-protamineeheparin concentrations at 3 min after protamine administration were similar in high [1.04 (0.50) IU,ml À1 ] and low [1.21 (0.45) IU,ml À1 ; P¼0.246] protamine dosing ratio groups, and no heparin rebound in the late postoperative period was reported.…”

In Response to: Calculating the Protamine Dose Necessary to Neutralize Heparin in All Patients Under All Circumstances by Jan R de Jong and Christa Boer

“…The heparin concentration calculation made by the HMS probably also is associated with inherent errors, which are most significant at lower concentrations. 5 Hence, the derived HMS protamine dose calculation may deviate from a theoretical true dose value. It should, at the same time, be emphasised that the HMS-based protamine dose is very predictable; why, the same information can be obtained by using a statistical model, in which the information about the patient's body surface area and dose of administered heparin are closely linked to the estimated blood volume and the circulating concentration of heparin, respectively.…”

“…A PK model requires easily accessible and well-defined input variables, such as patient length and weight, to calculate blood volume, heparin strength (IU/mg), the priming volume of the heart-lung machine, the timing and dosing of heparin administration, timing of protamine administration, and information regarding fluid shifts. Despite the different methods available to calculate blood volume, 2,4,5 this model would be relatively insensitive to errors in the calculation of this volume because its starting point is the same as its endpoint: the amount of heparin administered to the patient. An additional advantage of a PK approach is that it enables a correction for body temperature, which allows implementation during situations of deep hypothermia.…”