Children undergoing cardiac surgery are at increased risk for perioperative bleeding and allogeneic blood product transfusion. Although coagulopathy induced by cardiopulmonary bypass (CPB) is complex and multifactorial, post-bypass hypofibrinogenemia is an independent predictor of postoperative bleeding.

Fibrinogen concentrate has been proposed as an alternative to cryoprecipitate and fresh frozen plasma (FFP) in different clinical settings. Galas et al. compared fibrinogen concentrate with cryoprecipitate as first-line therapy in children with post-bypass bleeding. Children who underwent cardiac surgery with CPB were allocated to receive either fibrinogen concentrate (60 mg/kg) or cryoprecipitate (10 mL/kg) if bleeding was associated with fibrinogen levels <1 g/dL after CPB. Although this study was not sufficiently powered to detect any significant difference in postoperative bleeding and blood product transfusion requirements, it provides relevant information. About 40% of children included in both groups received additional doses of cryoprecipitate, which may indicate that the initial dose of both cryoprecipitate (10 mL/kg) and fibrinogen concentrate (60 mg/kg) was not adequate to significantly increase fibrinogen concentration within the first hour after administration. In addition, these results could be explained by the relatively low fibrinogen trigger used by the authors (<1.0 g/L) and the increased fibrinogen consumption observed in bleeding situations. Despite the fact that no studies have yet evaluated the dose-response relationship of fibrinogen concentrate in children undergoing cardiac surgery, several recent trials suggest that fibrinogen concentrate should be administered at a dose ≥100 mg/kg to significantly increase fibrinogen concentration and decrease postoperative bleeding. This study also confirms that, although fibrinogen concentrate is a promising alternative to increase fibrinogen level in bleeding situations, several questions remain unanswered, particularly in children undergoing cardiac surgery: 1) What component should be used for fibrinogen supplementation? 2) What is the safe and effective fibrinogen level to be targeted? 3) Which test should be used to guide fibrinogen administration? In conclusion, although fibrinogen concentrate could be considered as first-line therapy in children with bleeding after cardiac surgery, further studies are urgently needed to confirm which dose might be used to significantly and safely reduce postoperative bleeding. – David Faraoni
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