Circuit oxygenator contributes to extracorporeal membrane oxygenation-induced hemolysis

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Device Technology

Background:

• Extracorporeal membrane oxygenation (ECMO) is a life-support technology that can cause hemolysis, a condition linked to worse patient outcomes.
• Shear stress from blood flow within ECMO circuits and oxygenators is the suspected cause of this hemolysis.

Purpose of the Study:

• To investigate whether using a smaller oxygenator or an in-line hemofilter impacts hemolysis during ECMO.
• To determine the relationship between oxygenator size, pressure gradients, and ECMO-associated hemolysis.

Main Methods:

• ECMO circuits were tested using either an adult (1.8 m²) or pediatric (0.8 m²) oxygenator, or an adult oxygenator with an in-line hemofilter.
• Circuits were run for 6 hours, with plasma hemoglobin levels measured hourly to quantify hemolysis.
• Hemolysis was calculated as the change in plasma hemoglobin relative to a control, accounting for ECMO run time.

Main Results:

• The smaller pediatric oxygenator led to significantly higher plasma hemoglobin levels compared to the adult oxygenator (p = 0.02).
• A greater pressure gradient was observed with the pediatric oxygenator (p < 0.05).
• The addition of an in-line hemofilter did not alter plasma hemoglobin levels.

Conclusions:

• Employing a smaller dimension pediatric oxygenator during ECMO increases hemolysis and pressure gradients.
• These findings suggest that elevated shear forces from smaller oxygenators augment ECMO-induced hemolysis.