Variations in thromboelastography levels in blood exposed to membrane oxygenators

Area of Science:

• Biomedical Engineering
• Hematology
• Cardiovascular Surgery

Background:

• Thromboelastography (TEG) assesses hemostatic ability and is used in monitoring coagulation during extracorporeal circulation (ECC).
• The independent impact of ECC exposure on TEG parameters remains incompletely understood.
• Investigating the effects of membrane oxygenator circuits on blood coagulation is crucial for patient safety.

Purpose of the Study:

• To determine the effects of in vitro exposure to membrane oxygenators on TEG levels in whole human blood.
• To evaluate how different membrane coating types (polymer, heparin, non-coating) influence TEG parameters over time.

Main Methods:

• Heparinized whole blood from healthy volunteers was circulated through ECC circuits with polymer-coating, heparin-coating (HC), or non-coating (NC) membrane oxygenators.
• Thromboelastography (TEG) tests were conducted at 3, 6, 12, and 24 hours of circulation.
• Blood samples were reversed with protamine before TEG analysis; statistical analysis included ANOVA.

Main Results:

• Citrated kaolin with heparinase reaction times (CKHR) shortened at 6 and 12 hours, then prolonged at 24 hours.
• Citrated kaolin with heparinase maximum amplitude (CKHMA) increased from 6 to 12 hours.
• A significant difference in CKHR was noted between HC and NC at 6 hours, but other coating comparisons showed no significance.

Conclusions:

• TEG data suggest that blood's hemostatic capability is maintained after 12 hours of exposure to membrane surfaces in ECC circuits.
• The influence of different membrane coating types on TEG results requires further investigation.
• TEG remains a valuable tool for monitoring coagulation status during ECC.