During an elective procedure that turned into a full day case due to complications and significant bleeding, the patient required a second emergency initiation of CPB. Systemic heparinisation was administered by the anaesthetist. The perfusion team, comprising of the on call perfusionist and an additional perfusionist who remained beyond their scheduled hours added 15,000iu heparin to the CPB circuit. Despite the complex surgical circumstances, the second bypass run was well managed. There were no circuit related complications i.e. elevated arterial line pressures, and the CPB proceeded smoothly. Notably, the ACT remained consistently elevated (>1000 seconds) which is typical in cases of extensive heparinisation.

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Upon termination of bypass, the ACT device displayed a 'Heater Error'. The perfusionist suspected that this was either a device malfunction or overheating due to prolonged continuous use. This was also checked by the second perfusionist. Post bypass, the clinical environment remained highly active and busy, with IABP support, ongoing emergency cell salvage, and volume transfusion. Therefore, the perfusionists did not find it appropriate to inform the surgeons and anaesthetist of this error. Protamine was administered per standard protocol at the surgeon's request to reverse heparin effects. Normally, ACT values return close to baseline following reversal, however, in this instance the ACT continued to rise abnormally (>700 seconds). A repeat ACT sample tested on an alternative machine returned a value of 112 seconds, confirming that the intial device was likely faulty or had overheated. As far as I am aware no further protamine was administered and the case ended as expected.