*Thrombelastography-based monitoring for massive blood loss during pediatric surgery, a pilot study*

The management of massive blood loss in children during trauma or craniofacial
surgery is a huge and unsolved problem in pediatric surgery and anesthesia(1).
No clear strategies and no evidence-based treatment protocol exist. The
classical approach of volume replacement with crystalloid and colloid solutions
can seriously alter hemostatic function by diluting clotting factors and
further increasing intraoperative bleeding(2, 3). Therefore, it is common
practice to use also packed red blood cells (pRBC), fresh frozen plasma (FFP)
and concentrated platelets (CP) according to the clinical situation and
laboratory parameters. Unfortunately, transfusion of allogenic blood and blood
products is associated with a number of serious risks such as transmission of
infections, possible immunosuppressance and immunomodulation,
transfusion-related lung injury and adverse outcome associated to allogenic
transfusion(1, 4). High costs of blood and blood products and an increasing
awareness of these risks over the past years have led to develop management
strategies to minimize blood loss and to decrease the use of blood products(5).
In addition, the ongoing concerns regarding the availability of the national
and international blood supply and the remarkable increase in prices of blood
products during the past 10 to 15 years due to blood safety measures have
further boosted the call for alternative algorithms(6-8). Preoperative
assessment of hemostatic parameters has not been successful for identifying
patients who are at risk and will bleed excessively(9).
Primary non-syndromic craniosynostosis occurs in 1:2000 births. It affects the
child*s morphology and can lead to functional impairments. Primary operative
repair of craniosynostosis in infants and young children is recommended.
Unfortunately, this procedure can lead to excessive blood loss and is
associated with an average loss of 60 to 100 % (!) of the estimated blood
volume(10, 11). Therefore, these well-planned operations are a model for
excessive acute blood loss especially in children. Our institution performs
more than 100 of these craniofacial surgeries per year, which accounts for
nearly 90% of such operations in The Netherlands.
Thromboelastography (TEG) is a clinical monitoring method which quantifies the
effects of blood loss on blood coagulation(12). It is based on the interaction
of platelets and plasma coagulation factors and their ability to form a
functional clot and then dissolve the clot through fibrinolysis. Nowadays, two
thromboelastographic techniques are available (ROTEM® and TEG®). The efficacy
of both techniques has been found to be highly comparable (oral communication
April 2008 by Michael Spannagl, Klinikum der Universität München, Germany).
However, the feasibility in a pediatric laboratory has to be established. The
introduction of TEG has led to a significant decrease in red cell transfusions,
use of fresh frozen plasma (FFP) and platelet transfusions in adult surgery and
thereby diminishing the risks of infections and immunosuppression and moreover
a significant decrease in accompanying costs(4, 13). These data strongly
support the evaluation of TEG-guided interventions in children. In the future
TEG during pediatric surgery will allow for tailored interventions that will
include the transfusion of crystalloid and colloid solutions, pRBC, FFP, and
CP, as well as the administration of specific medications like antifibrinolytic
agents, concentrates of fibrinogen, or activated recombinant factor VII.
Finally, TEG tailored therapy may decrease transfusion related complications in
children.
We plan this pilot study to establish pediatric reference values for TEG
analysis parameters during craniofacial surgery, and to compare the
feasibility of two thromboelastographic techniques in our pediatric laboratory.

REFERENCES
1.New HV. Paediatric transfusion. Vox Sang 2006;90(1):1-9.
2.Hobisch-Hagen P. Hemodilution and coagulation. An overview. Minerva
Anestesiol 2002;68(4):178-81.
3.Ng KF, Lam CC, Chan LC. In vivo effect of haemodilution with saline on
coagulation: a randomized controlled trial. Br J Anaesth 2002;88(4):475-80.
4.Spiess BD, Gillies BS, Chandler W, Verrier E. Changes in transfusion therapy
and reexploration rate after institution of a blood management program in
cardiac surgical patients. J Cardiothorac Vasc Anesth 1995;9(2):168-73.
5.CBO KvdG. Richtlijn Bloedtransfusie, Kwaliteitsinstituut voor de
Gezondheidszorg CBO. 2004.
6.Goodnough LT, Shander A, Brecher ME. Transfusion medicine: looking to the
future. Lancet 2003;361(9352):161-169.
7.Greinacher A, Fendrich K, Alpen U, Hoffmann W. Impact of demographic changes
on the blood supply: Mecklenburg-West Pomerania as a model region for Europe.
Transfusion 2007;47(3):395-401.
8.McCarthy LJ. How do I manage a blood shortage in a transfusion service?
Transfusion 2007;47(5):760-2.
9.Dorman BH, Spinale FG, Bailey MK, Kratz JM, Roy RC. Identification of
patients at risk for excessive blood loss during coronary artery bypass
surgery: thromboelastography versus coagulation screen. Anesth Analg
1993;76(4):694-700.
10.Tuncbilek G, Vargel I, Erdem A, Mavili ME, Benli K, Erk Y. Blood loss and
transfusion rates during repair of craniofacial deformities. J Craniofac Surg
2005;16(1):59-62.
11.Hildebrandt B, Machotta A, Riess H, Kerner S, Ahlers O, Haberl H, et al.
Intraoperative fresh-frozen plasma versus human albumin in craniofacial
surgery--a pilot study comparing coagulation profiles in infants younger than
12 months. Thromb Haemost 2007;98(1):172-7.
12.Salooja N, Perry DJ. Thrombelastography. Blood Coagul Fibrinolysis
2001;12(5):327-37.
13.Shore Lesserson L, DePerio M, Francis S, Vela Cantos F, Ergin A.
Thromboelastography guided transfusion algorithm reduces transfusions in
complex cardiac surgery. Anaesth Analg 1999;88:312-319.

We plan a pilot study to obtain normal reference values of TEG parameters
during craniofacial surgery. Two machines will be tested: the TEG and the
ROTEM.

We will perform a single-center pilot study to obtain TEG-values in 50 children
during surgical repair of primary craniosynostosis. The anesthetic management,
fluid replacement and transfusion of blood components will be done according to
clinical routine. All children will receive a standardized infusion protocol.
During surgery six times 5 ml of blood will be drawn from an in situ infusion
line. TEG data will not be used for patiet treatment but only used for this
study.

no burden and / or risks as the children are under anesthesia.