Hemostatic response in paediatric patients undergoing cardiopulmonary bypass surgery

Area of Science:

• Pediatric Cardiac Surgery
• Hemostasis and Thrombosis
• Anesthesiology

Background:

• Cardiopulmonary bypass (CPB) surgery is critical for pediatric cardiac procedures.
• Understanding hemostatic balance during and after CPB is essential for patient outcomes.
• Heparin and protamine are standard agents, but their precise effects on coagulation in children require further elucidation.

Purpose of the Study:

• To prospectively evaluate the hemostatic response in children aged up to 6 years undergoing CPB surgery.
• To investigate the mechanisms of thrombin generation inhibition during and after CPB, particularly post-protamine administration.
• To determine if residual unfractionated heparin (UFH) contributes to persistent thrombin inhibition.

Main Methods:

• Prospective, single-center cohort study involving children up to 6 years old undergoing CPB.
• Collection of blood samples at eight distinct time points during the perioperative period.
• Analysis of coagulation parameters, including unfractionated heparin (UFH) effect, thrombin generation, and tissue factor pathway inhibitor (TFPI) levels.

Main Results:

• UFH administration significantly increased its effect, which was subsequently reduced by protamine.
• Thrombin generation remained significantly inhibited post-protamine compared to baseline.
• Increased levels of free and total tissue factor pathway inhibitor (TFPI) were observed during CPB, suggesting a role in persistent thrombin inhibition.

Conclusions:

• Protamine effectively reverses the direct effects of UFH, but does not fully restore thrombin generation to baseline levels in pediatric CPB patients.
• Persistent thrombin inhibition post-protamine is not attributable to residual UFH.
• Elevated TFPI levels during CPB may be a key factor contributing to the ongoing inhibition of thrombin generation after protamine reversal, necessitating further investigation.