Introduction: Heparin is a requirement of cardiopulmonary bypass as it prevents contact activation, however, it increases patients risk of bleeding. Cardiotomy suction combats this by reducing patient blood loss during surgery. Protamine is used to reverse the effects of heparin post-surgery. Discrepancies exist within the perfusion community regarding the appropriate time to turn off cardiotomy suction. If cardiotomy suction is left on during protamine administration, there is concern that the circuit may become compromised due to clot development. The primary focus of this study is to evaluate if this assumption is valid. Additionally, a survey questionnaire investigating the common practices around this topic was also conducted.

Method: An observational study was conducted where 20 patients were selected to have multiple ACT samples taken during protamine administration and compared against a control sample before protamine had been given. The samples taken from each patient included the last ACT on bypass, a control sample before protamine administration, and a sample after the test dose of 50mg, half of the protamine, and all of the protamine had been given. As well as samples at 1.5 mins, 2.5 mins, 3 mins, and 4 mins after all protamine had been given. ACT results were used as our primary endpoint as they correlate to the coagulation status of the patient and the quality of the blood being sucked back into the CPB circuit via the cardiotomy suction.

Results: The ACT results showed that 95% of samples were outside the therapeutic range for cardiotomy suction to be turned on after the test dose of protamine had been given (95% C.I. = 75, 99). 100% of the samples returned to baseline ACT values after half of the protamine was given (95% C.I.= 83,100).  

Conclusion: It is unsafe to leave cardiotomy suction on during protamine administration.

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