Hemolysis during long-term extracorporeal membrane oxygenation

Area of Science:

• Pediatric critical care medicine
• Cardiopulmonary bypass technology
• Hematology and coagulation

Background:

• Extracorporeal membrane oxygenation (ECMO) is a life-support measure for infants with severe cardiorespiratory failure.
• Hemolysis, or red blood cell destruction, is a known complication of ECMO, but its precise cause remains unclear.
• Understanding hemolysis during ECMO is crucial for improving patient outcomes and device safety.

Purpose of the Study:

• To investigate the underlying causes of hemolysis in infants undergoing ECMO.
• To correlate hematologic and coagulation changes with the occurrence of hemolysis during ECMO.
• To identify factors contributing to hemolysis in the ECMO circuit.

Main Methods:

• Prospective monitoring of hematologic and coagulation profiles in seven infants receiving ECMO.
• Utilized a constrained vortex pump for all ECMO procedures.
• Measured plasma free hemoglobin, fibrinogen levels, and fibrin degradation products over time.

Main Results:

• Plasma free hemoglobin remained low initially but increased significantly after 48 hours in conjunction with visible circuit clots.
• Elevated fibrin degradation products and decreased fibrinogen levels were observed concurrently with rising plasma hemoglobin.
• Complete circuit changes normalized hemolysis markers, while component changes or transfusions did not.

Conclusions:

• Prolonged ECMO use can lead to circuit thrombosis, which subsequently causes hemolysis in infants.
• Circuit thrombosis, not just pump mechanics or blood transfusions, appears to be the primary driver of hemolysis.
• Further research is warranted to elucidate the specific role of the constrained vortex pump in ECMO-related hemolysis.