Introduction: One of the side effects of non steroidal anti-inflammatory drugs (NSAIDs) is the inhibition of platelet aggregation, which could increase bleeding after cardiac surgery . The aim of our study was to analyse the effects of diclofenac on coagulation, platelet function and blood loss after cardiac surgery.
Method: In a controlled, blinded, randomized trial we studied 39 patients undergoing elective cardiac surgery using an extracorporeal circuit. Patients were randomly assigned to one of the two treatment groups. The diclofenac (D) group received 75 mg of diclofenac intravenously 3 hours after surgery and the control (C) group received no diclofenac. We registered haemodynamic data and blood loss hourly for 16 hours after surgery. Blood samples for coagulation tests including platelet function were taken before, immediately after, 5 hours after and 16 hours after surgery. Statistical analysis was by ANOVA, Student's t-test and X2 test.
Results: 21 patients were in the D group and 18 patients in the C group. There were no differences between the groups with respect to demographic data, concurrent disease and medication used by the patients.
The time course of blood loss (Figure 1) and the volume of blood lost within 16 hours after surgery were similar in both groups. PTT, aPTT and platelet count decreased significantly after surgery and recovered gradually after 16 hours but no differences were found between the groups. Aggregation of platelets decreased significantly after surgery. After administration of diclofenac aggregation of platelets to hidon and nefrin decreased in the D but not in the C group. The difference between the groups was significant only for the nefrin test 5 hours after surgery.
Discussion: The impairment of platelet function caused by diclofenac was not associated with clinically important increase in bleeding after cardiac surgery. The power of the study was set to 0.8 to detect a difference in bleeding of 300 mL within 16 hours between the two groups.
1 Griffin M. Con: Nonsteroidal anti-inflammatory drugs should not be routinely administered for postoperative analgesia after cardiac surgery. J Cardiothorac Vasc Anesth