Thrombelastography-Based Monitoring for Massive Blood Loss During Elective Pediatric Surgery for Craniosynostosis Repair, a Pilot Study.
Authors: Appel V Inge M. , Machotta Andreas , Poley Marten , Al Maiwenn J 
Published: October 2019

Abstract
Abstract 2110
Poster Board II-87
The management of massive blood loss in children during trauma or major surgery is still an unsolved problem in pediatric surgery and anesthesia. Primary operative repair of craniosynostosis in infants and young children can serve as a model for excessive acute blood loss. The introduction of thromboelastography (TEG) has led to a significant decrease in transfusion of packed red blood cells (pRBC), fresh frozen plasma (FFP) and platelets in adult surgery, thereby diminishing the risks of infections and immunosuppression. Moreover a significant decrease in accompanying costs has been reported. However, no studies have evaluated the effect of TEG-guided treatment on the amount of transfused blood products in children.
The primary objective of this pilot study is to obtain reference TEG-values in children during surgical repair of primary craniosynostosis. We performed a single-center pilot study on TEG-monitoring in children during craniofacial surgery.

Methods:
The study includes 21 children with craniosynostosis undergoing elective craniofacial repair at the Sophia Children's Hospital, Erasmus Medical Center, Rotterdam, The Netherlands. Blood samples (5 ml blood taken from an arterial line) for TEG (Haemoscope®) measurement were obtained after induction of anesthesia (T1), after the application of Ringer's lactated solution (RLS) 10 ml × kg-1 body weight (T2), after the application of hetastarch 130/0.4 6% (Venofundin®, Fresenius Kabi) (T3), after transfusion of pRBC (T4), and eventually after the application of FFP (T5).

Results:
21 children, less than 20 months of age, with a mean body weight of 8.5 kg underwent surgical repair of craniosynostosis. They were treated according to the local protocol on massive blood loss in children during surgery. Nine children were suffering from scaphocephalie, 4 from trigonocephalie, 3 from plagiocephalie, one from brachycephalie and 4 children had a mixed or complex form of craniosynostosis such as Crouzon disease.
After the induction of anaesthesia (T1) and after the administration of RLS (T2) no changes in clot strength were seen, MA remained mean 62 mm. However, between T2 and T3 all children demonstrated a significant decline in hemoglobine from mean 6.5 to 3.8 mmol/L (p<.0005). The blood loss was mean 380 ml at T3, ranging from 200 to 700 ml, requiring mean 190 ml transfusion of pRBC (range 100-390 ml). The TEG values at T3 showed a concurrent decrease of alpha (from 66° to 57°) and MA (from 62 to 48mm) with an increasing k (from 1.7 to 3.0 min) in kaolin activated TEG measurements. Together with a decrease in MA in TEG–FF at T3 (from 18 to 5.5 mm) this demonstrates a dilutional coagulopathy. All changes were highly significant with p<.0005. Transfusion of pRBC at T4 did not change TEG parameters. No signs of fibrinolysis were seen.

Discussion:
The administration of hetastarch 130/0.4 6% at T3 resulted in a dilutional coagulopathy. This is due to blood loss, consumption of coagulation factors and platelets, and intravascular volume replacement. During blood loss fibrinogen synthesis will be limited. Additionally, the decreasing functional fibrinogen levels (MA-FF) point to reduced strength of the clot. Administering cryoprecipitate or concentrates of fibrinogen in an early phase might maintain clot firmness and thereby decrease blood loss and reduce the number of transfused blood products.

Conclusion:
In an attempt to decrease the amount of transfused blood products TEG will allow tailored interventions during pediatric surgery with specific medications like antifibrinolytic agents, concentrates of fibrinogen, or activated recombinant factor VII. Finally, TEG tailored therapy may decrease blood transfusions and transfusion related complications in children. These data strongly support the evaluation of TEG-guided interventions in children during massive blood loss.

Disclosures:
No relevant conflicts of interest to declare.