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.