DISCUSSION
Our results suggest that a low dose protamine infusion given in the immediate postoperative period does not lead to any significant clinical benefits. Both patients receiving and not receiving the infusion had similar postoperative drainage, transfusion requirements, hemorrhagic morbidity, mortality and length of hospital stay. Patients who received Protamine infusion needed less FFP (.044 vs 0.69 unit/patient), P value 0.015 (Table 1)
Even in patients with high BMI who received protamine, there was no significant difference in total and indexed blood loss.
There is limited evidence for the use of additional postoperative protamine administration to combat heparin rebound in the intensive care setting. A single randomised controlled trial has been performed showing a significant biochemical improvement in heparin rebound with a modest reduction of postoperative bleeding with the use of a 6-hour protamine infusion in intensive care. Similar to our study however the clinical benefit of this was unclear with no significant transfusion benefit found. A similar complication profile was noted with no significant difference found between the groups with regards to morbidity and mortality (11)
Whilst little doubt remains regarding the phenomenon of heparin rebound after cardiopulmonary bypass there is little evidence to show a significant number of patients suffer clinical consequences. In addition, our study along with previous evidence fails to show any significant clinical benefit in providing additional protamine in the postoperative phase.
Haemorrhage and the transfusion requirements associated with this continue to have significant morbidity and mortality consequences for our patients post cardiac surgery. This bleeding is multifactorial in aetiology and it appears whilst heparin rebound may have a role in this its clinical significance is limited and the reversal of the effect with protamine infusion lead to little if any significant benefits for our patients. When compared, the two groups did not show any difference in terms of the total postoperative stay.