Heparin-induced thrombocytopenia in patients on extracorporeal membrane oxygenation and the role of a heparin-bonded circuit.

BACKGROUND: In patients supported with extracorporeal membrane oxygenation, and who develop heparin-induced thrombocytopenia, there is no clear evidence to support changing to a non-heparin-coated extracorporeal membrane oxygenation circuit. Our goal was to evaluate clinical outcomes of patients who were continued on heparin-bonded circuits despite diagnosed heparin-induced thrombocytopenia. METHODS: We completed a single-center retrospective study of all patients who underwent extracorporeal membrane oxygenation support from July 2008 to July 2017 and were tested heparin-induced thrombocytopenia positive while on extracorporeal membrane oxygenation support. After diagnosis of heparin-induced thrombocytopenia, mean platelet count (k/µL) was measured on consecutive days for 14 days. RESULTS: Out of 455 patients, 14 (3.1%) had a diagnosis of heparin-induced thrombocytopenia by serotonin release assay and systemic heparin treatment was discontinued in every case. In total, 11 of the heparin-induced thrombocytopenia patients (78.6%) survived to discharge. The overall survival of all 455 extracorporeal membrane oxygenation patients was 54.1%. Platelets counts after discontinuation of systemic heparin in the heparin-induced thrombocytopenia patients increased from a mean of 59.8 k/µL at time of heparin-induced thrombocytopenia diagnosis to a mean of 280.2 k/µL at 14 days after discontinuation of heparin despite continuation of the heparin-bonded circuit. Platelet count increased in heparin-induced thrombocytopenia patients on extracorporeal membrane oxygenation support after discontinuation of systemic heparin even if maintained on the heparin-bonded circuit. CONCLUSION: Discontinuation of systemic heparin but continuation of heparin-coated extracorporeal membrane oxygenation circuits appeared to be an appropriate response for our extracorporeal membrane oxygenation-supported patients who developed heparin-induced thrombocytopenia. Survival in this group was not significantly different to those patients on extracorporeal membrane oxygenation without heparin-induced thrombocytopenia. Larger studies should evaluate the safety of heparin-bonded extracorporeal membrane oxygenation systems in heparin-induced thrombocytopenia patients.

Non-Cardiac Symptoms of Moderate to Severe Hypokalemia in a Patient with a Syncardia™ Total Artificial Heart.

The Syncardia™ total artificial heart (TAH) is an option for patients as a bridge to transplant in those who are not candidates for left ventricular assist devices (LVAD) due to right ventricular failure. Postoperative course is highly dependent on volume status and aggressive diuresis is often necessary. One complication from aggressive diuresis is hypokalemia; however, in these patients we tolerate a lower potassium level because cardiac arrhythmias are not a concern.  However, in two separate instances non-cardiac symptoms related to severe hypokalemia occurred. These symptoms included nystagmus in one patient and agitation, tremors, and having an "out-of-body" experience in the other patient. Both these patients had resolution of symptoms with potassium replacement.

Percutaneous Endoscopic Gastrostomy Tube in a Syncardia™ Total Artificial Heart.

As a bridge to transplant, the Syncardia™ total artificial heart (TAH) is an option for patients who are not candidates for left ventricular assist devices (LVAD) due to right ventricular failure. The need for nutritional support in these patients is essential for a favorable outcome. Low body mass indexes and albumin levels have been associated with increased morbidity and mortality in cardiac surgery patients [Alverdy 2003]. It is not uncommon for postoperative patients to have difficulty in consuming enough calories after surgery, which is further complicated by a hypermetabolic demand due to surgical stress. Enteral nutrition has typically been favored for gut mucosal integrity and bacterial flora [Alverdy 2003] [Engleman 1999]. We describe the need for prolonged enteral nutritional support in a TAH patient that was accomplished with a percutaneous endoscopic gastrostomy (PEG) tube.