Platelet activation in warm and cold heart surgery
C D Mazer1, A Hornstein, J Freedman
1Department of Anaesthesia, St. Michael's Hospital, University of Toronto, Ontario, Canada.
The Annals of Thoracic Surgery
|June 1, 1995
Summary
Warm heart surgery may reduce bleeding by affecting platelet activation similarly in both warm and cold cardiopulmonary bypass. This study investigated platelet changes during these procedures.
Area of Science:
- Cardiovascular Surgery
- Hematology
- Surgical Research
Background:
- Warm heart surgical procedures are anecdotally linked to reduced postoperative bleeding.
- Platelet activation is a potential mechanism influencing bleeding post-cardiac surgery.
Purpose of the Study:
- To investigate platelet activation and integrity differences during normothermic versus hypothermic cardiopulmonary bypass.
- To determine if observed differences in platelet markers correlate with postoperative blood loss.
Main Methods:
- Measured platelet count, membrane glycoproteins (GPIb, GPIIb/IIIa, GMP 140), and fragments.
- Assessed these markers before, during, and after normothermic (37°C) and hypothermic (28-30°C) cardiopulmonary bypass.
- Monitored granulocyte response and 24-hour postoperative blood loss.
Main Results:
- Cardiopulmonary bypass significantly decreased platelet count, GPIb, and fragments, while increasing GMP 140 (p < 0.05).
- Normothermic bypass showed an early granulocyte increase; hypothermic bypass showed a delayed increase post-rewarming.
- Mean 24-hour postoperative blood loss was similar between cold (786 mL) and warm (547 mL) groups (p=NS).
Conclusions:
- Cardiopulmonary bypass impacts platelet activation and integrity irrespective of temperature.
- The observed changes in platelet markers and blood loss were comparable between normothermic and hypothermic techniques.
- Temperature during cardiopulmonary bypass does not appear to significantly alter platelet response or bleeding outcomes.
