Higher fibrinogen concentrations for reduction of transfusion requirements during major paediatric surgery: A prospective randomised controlled trial.

BACKGROUND: Hypofibrinogenaemia is one of the main reasons for development of perioperative coagulopathy during major paediatric surgery. The aim of this study was to assess whether prophylactic maintenance of higher fibrinogen concentrations through administration of fibrinogen concentrate would decrease the volume of transfused red blood cell (RBCs). METHODS: In this prospective, randomised, clinical trial, patients aged 6 months to 17 yr undergoing craniosynostosis and scoliosis surgery received fibrinogen concentrate (30 mg kg(-1)) at two predefined intraoperative fibrinogen concentrations [ROTEM(®) FIBTEM maximum clot firmness (MCF) of <8 mm (conventional) or <13 mm (early substitution)]. Total volume of transfused RBCs was recorded over 24 h after start of surgery. RESULTS: Thirty children who underwent craniosynostosis surgery and 19 children who underwent scoliosis surgery were treated per protocol. During craniosynostosis surgery, children in the early substitution group received significantly less RBCs (median, 28 ml kg(-1); IQR, 21 to 50 ml kg(-1)) compared with the conventional fibrinogen trigger of <8 mm (median, 56 ml kg(-1); IQR, 28 to 62 ml kg(-1)) (P=0.03). Calculated blood loss as per cent of estimated total blood volume decreased from a median of 160% (IQR, 110-190%) to a median of 90% (IQR, 78-110%) (P=0.017). No significant changes were observed in the scoliosis surgery population. No bleeding events requiring surgical intervention, postoperative transfusions of RBCs, or treatment-related adverse events were observed. CONCLUSIONS: Intraoperative administration of fibrinogen concentrate using a FIBTEM MCF trigger level of <13 mm can be successfully used to significantly decrease bleeding, and transfusion requirements in the setting of craniosynostosis surgery, but not scoliosis. CLINICAL TRIAL REGISTRY NUMBER: ClinicalTrials.gov NCT01487837.

[Therapy of inherited diseases of platelet function. Interdisciplinary S2K guideline of the Permanent Paediatric Committee of the Society of Thrombosis and Haemostasis Research (GTH e. V.)]. / Therapie hereditärer Thrombozytopathien. Interdisziplinäre S2K-Leitlinie der Ständigen Kommission Pädiatrie der Gesellschaft für Thrombose- und Hämostaseforschung e. V.

Inherited disorders of platelet function are a heterogeneous group. For optimal prevention and management of bleeding, classification and diagnosis of the underlying defect are highly recommended. An interdisciplinary guideline for a diagnostic approach has been published (AWMF # 086-003 S2K; Hämostaseologie 2014; 34: 201-212). Underlying platelet disorder, platelet count, age and clinical situation modify treatment. Exclusive transfusion of platelet concentrates may be inappropriate as potentially adverse effects can outweigh its benefit. A stepwise and individually adjusted approach for restitution and maintenance of haemostasis is recommended. Administration of antifibrinolytics is generally endorsed, but is of particular use in Quebec disease. Restricted to older children, desmopressin is favourable in storage pool disease and unclassified platelet disorders. Although licensed only for patients with Glanzmann thrombasthenia and alloantibodies, in clinical practice rFVIIa is widely used in inherited platelet disorders with severe bleeding tendency. This guideline aims at presenting the best available advice for the management of patients with inherited platelet function disorders.

[Diagnosis of inherited diseases of platelet function. Interdisciplinary S2K guideline of the Permanent Paediatric Committee of the Society of Thrombosis and Haemostasis Research (GTH e. V.)]. / Diagnose angeborener Störungen der Thrombozytenfunktion. Interdisziplinäre S2K-Leitlinie der Ständigen Kommission Pädiatrie der Gesellschaft für Thrombose- und Hämostaseforschung e. V.

Congenital disorders of platelet function are a heterogeneous group of disorders that are often not detected until bleeding occurs. In clinical settings only a few methods have proven to be useful for identification and classification of inherited platelet disorders. For a rational diagnostic approach, a stepwise algorithm is recommended. Patient history and clinical investigation are mandatory. Von Willebrand disease and other coagulation disorders should always be ruled out prior to specific platelet testing. Platelet count, size, volume (MPV) and morphology may guide further investigations. The PFA-100® CT is suited for screening for severe platelet defects. Platelet aggregometry allows assessment of multiple aspects of platelet function. Flow cytometry enables diagnosis of thrombasthenia Glanzmann, Bernard-Soulier syndrome and storage pool defects. Molecular genetics may confirm a putative diagnosis or pave the way for identifying new defects. We present an unabridged version of the interdisciplinary guideline.

T-cell receptor Vß skewing frequently occurs in refractory cytopenia of childhood and is associated with an expansion of effector cytotoxic T cells: a prospective study by EWOG-MDS.

Immunosuppressive therapy (IST), consisting of antithymocyte globulin and cyclosporine A, is effective in refractory cytopenia of childhood (RCC), suggesting that, similar to low-grade myelodysplastic syndromes in adult patients, T lymphocytes are involved in suppressing hematopoiesis in a subset of RCC patients. However, the potential role of a T-cell-mediated pathophysiology in RCC remains poorly explored. In a cohort of 92 RCC patients, we prospectively assessed the frequency of T-cell receptor (TCR) ß-chain variable (Vß) domain skewing in bone marrow and peripheral blood by heteroduplex PCR, and analyzed T-cell subsets in peripheral blood by flow cytometry. TCRVß skewing was present in 40% of RCC patients. TCRVß skewing did not correlate with bone marrow cellularity, karyotype, transfusion history, HLA-DR15 or the presence of a PNH clone. In 28 patients treated with IST, TCRVß skewing was not clearly related with treatment response. However, TCRVß skewing did correlate with a disturbed CD4(+)/CD8(+) T-cell ratio, a reduction in naive CD8(+) T cells, an expansion of effector CD8(+) T cells and an increase in activated CD8(+) T cells (defined as HLA-DR(+), CD57(+) or CD56(+)). These data suggest that T lymphocytes contribute to RCC pathogenesis in a proportion of patients, and provide a rationale for treatment with IST in selected patients with RCC.

Prognostic value of nucleated red blood cells in critically ill children.

QUESTION: Is there an association between the presence of nucleated red blood cells (NRBCs) in the peripheral blood and outcomes in critically ill children? METHODS: Prospective observational study conducted in 2008 (January to December) in a multidisciplinary paediatric intensive care unit (PICU) of a tertiary children's hospital. We provide univariate analysis, stratified by age group (neonates and children >28 days of age), and multiple logistic regression, comparing clinically important outcomes (death, ventilation, renal replacement therapy, inotropic support) with haematological (NRBC, haemoglobin, platelets, leucocytes), illness severity (expected mortality [paediatric index of mortality, PIM2]), demographic (age, sex) and diagnostic parameters and length of stay. Haematological parameters correspond to the first 24 hours of PICU admission. RESULTS: Out of 670 patients, 195 (29.1%) were NRBC positive and 475 (70.9%) were NRBC negative. In the neonatal age group (n = 232), patients who died, were ventilated or received inotropic support had significantly more NRBCs than patients without these conditions (p = 0.032, 0.038 and 0.029, respectively). In the child age group (n = 438), only renal replacement therapy was significantly associated with NRBC (p <0.001). High PIM score (p <0.001) and longer length of stay (p <0.001) were independently associated with bad outcomes (composite endpoint: mortality and/or ventilation and/or renal replacement therapy and/or inotropic support); NRBC positivity was not an independent predictor of bad outcome (odds ratio 1.44, 95% confidence interval 0.62‒3.41). CONCLUSIONS: NRBCs are not an independent risk factor for bad outcomes in paediatric intensive care. However, NRBCs may have some prognostic value in the first month of life. In children >1 month of age, the association between NRBC and outcome is much less pronounced.

Comparison of thromboelastometry (ROTEM®) with standard plasmatic coagulation testing in paediatric surgery.

BACKGROUND: Thromboelastometry (ROTEM(®)) might be useful to detect intraoperative coagulation disorders early in major paediatric surgery. This observational trial compares this technique to standard coagulation tests. METHODS: Intraoperative blood sampling was obtained in children undergoing elective major surgery. At each time point, standard coagulation tests [activated partial thromboplastin time (aPTT), prothrombin time (PT), and fibrinogen level] and ROTEM(®) analyses (InTEM, ExTEM, and FibTEM) were performed simultaneously by trained hospital laboratory staff. RESULTS: A total of 288 blood samples from 50 subjects were analysed. While there was a poor correlation between PT and aPTT to ExTEM clotting time (CT) and InTEM CT, respectively, a good correlation was detected between PT and aPTT to clot formation time, and a very good correlation between fibrinogen level and FibTEM assay (r=0.882, P<0.001). Notably, 64% of PT and 94% of aPTT measurements were outside the reference range, while impaired CT was observed in 13% and 6.3%, respectively. Standard coagulation test results were available after a median of 53 min [inter-quartile range (IQR): 45-63 min], whereas 10 min values of ROTEM(®) results were available online after 23 min (IQR: 21-24 min). CONCLUSIONS: PT and aPTT cannot be interchangeably used with ROTEM(®) CT. Based on the results of ROTEM(®), recommended thresholds for PT and aPTT might overestimate the need for coagulation therapy. A good correlation was found between the fibrinogen level and the FibTEM assay. In addition, ROTEM(®) offered faster turnaround times.

Accuracy and precision of hemoglobin point-of-care testing during major pediatric surgery.

INTRODUCTION: The aim of the study was to compare accuracy and reproducibility of four point-of-care testing (POCT) devices (GEM® Premier 3000, ABL 800 flex, GEM® OPL™, HemoCue® B-Hemoglobin) for hemoglobin (Hb) analyzes as compared with the reference laboratory method (Sysmex XE 2100) in children undergoing major surgery. METHODS: Pediatric patients undergoing craniofacial, spine, hip, or cancer surgery were included. Blood samples for Hb testing were taken at several intraoperative time points and generally withdrawn from the arterial catheter, if accessible. RESULTS: A total of 256 blood samples were taken intraoperatively from 71 pediatric patients. All POCT devices showed very small bias (maximum -0.46 g/dL) to reference method as well as very good reproducibility (maximum coefficient of variation of 0.99%). However, in two cases (HemoCue), potential clinical relevant differences were observed beyond a range of 2 g/dL. CONCLUSION: All POCT devices tested and operated by trained staff for hemoglobinometry showed reliable test results. They all allow for simple, fast, and precise bedside determination of hemoglobin concentration in the intraoperative setting.

Hematopoietic stem cell transplantation for advanced myelodysplastic syndrome in children: results of the EWOG-MDS 98 study.

We report on the outcome of children with advanced primary myelodysplastic syndrome (MDS) transplanted from an HLA-matched sibling (MSD) or an unrelated donor (UD) following a preparative regimen with busulfan, cyclophosphamide and melphalan. Ninety-seven patients with refractory anemia with excess blasts (RAEB, n=53), RAEB in transformation (RAEB-T, n=29) and myelodysplasia-related acute myeloid leukemia (MDR-AML, n=15) enrolled in the European Working Group of MDS in Childhood (EWOG-MDS) 98 study and given hematopoietic stem cell transplantation (HSCT) were analyzed. Median age at HSCT was 11.1 years (range 1.4-19.0). Thirty-nine children were transplanted from an MSD, whereas 58 were given the allograft from a UD (n=57) or alternative family donor (n=1). Stem cell source was bone marrow (n=69) or peripheral blood (n=28). With a median follow-up of 3.9 years (range 0.1-10.9), the 5-year probability of overall survival is 63%, while the 5-year cumulative incidence of transplantation-related mortality (TRM) and relapse is 21% each. Age at HSCT greater than 12 years, interval between diagnosis and HSCT longer than 4 months, and occurrence of acute or extensive chronic graft-versus-host disease were associated with increased TRM. The risk of relapse increased with more advanced disease. This study indicates that HSCT following a myeloablative preparative regimen offers a high probability of survival for children with advanced MDS.

Hyperbilirubinemia and rapid fatal hepatic failure in severe combined immunodeficiency caused by adenosine deaminase deficiency (ADA-SCID).

Adenosin deaminase (ADA) deficiency is the cause for Severe Combined Immunodeficiency (SCID) in about 15% of patients with SCID, often presenting as T (-)B (-)NK (-)SCID. Treatment options for ADA-SCID are enzyme replacement, bone marrow transplantation or gene therapy. We here describe the first patient with ADA-SCID and fatal hepatic failure despite bone marrow transplantation from a 10/10 HLA identical related donor. As patients with ADA-SCID may be at yet underestimated increased risk for rapid hepatic failure we speculate whether hepatitis in ADA-SCID should lead to the immediate treatment with enzyme replacement by pegylated ADA.

Thromboelastometry (ROTEM) in children: age-related reference ranges and correlations with standard coagulation tests.

BACKGROUND: The small sample volume needed and the prompt availability of results make viscoelastic methods like rotational thromboelastometry (ROTEM) attractive for monitoring coagulation in small children. However, data on reference ranges for ROTEM parameters in children are scarce. METHODS: Four hundred and seven children (ASA I and II) undergoing elective surgery were recruited for this prospective, two-centre, observational study. Subjects were grouped as follows: 0-3, 4-12, 13-24 months, 2-5, 6-10, and 11-16 yr. Study objectives were to establish age-dependent reference ranges for ROTEM assays, analyse age dependence of parameters, and compare ROTEM data with standard coagulation tests. RESULTS: Data from 359 subjects remained for final analysis. Except for extrinsically activated clot strength and lysis, parameters for ROTEM assays were significantly different among all age groups. The most striking finding was that subjects aged 0-3 months exhibited accelerated initiation (ExTEM coagulation time: median 48 s, Q1-Q3 38-65 s; P=0.001) and propagation of coagulation (α angle: median 78(o), Q1-Q3 69-84(o); P<0.001) and maximum clot firmness (median 62 mm, Q1-Q3 54-74 mm), although standard plasma coagulation test results were prolonged (prothrombin time: median 13.2 s, Q1-Q3 12.6-13.6 s; activated partial thromboplastin time: median 42 s, Q1-Q3 40-46 s). Lysis indices of <85% were observed in nearly one-third of all children without increased bleeding tendency. Platelet count and fibrinogen levels correlated significantly with clot strength, and fibrinogen levels correlated with fibrin polymerization. CONCLUSIONS: Reference ranges for ROTEM assays were determined for all paediatric age groups. These values will be helpful when monitoring paediatric patients and in studies of perioperative coagulation in children.

In vitro and in vivo stability of diluted recombinant factor VIII for continuous infusion use in haemophilia A.

Factor VIII (FVIII) replacement by continuous infusion (CI) is used postoperatively or after significant bleeding. For young paediatric patients, CI may require FVIII dilution. Variable stabilities of diluted full-length recombinant FVIII Kogenate FS (KG-FS) have been reported under different storage conditions. We investigated the recovery and stability of diluted KG-FS in vitro and in vivo. Kogenate FS was diluted to 50-120 U mL(-1) and its recovery and stability in glass vials or polypropylene syringes was determined. Furthermore, stability of KG-FS diluted to 80 U mL(-1)'administered' via single- and double-pump mock CI systems was tested. Finally, the in vivo stability of KG-FS diluted to approximately 60 U mL(-1) and administered postsurgically by CI with the double-pump to a paediatric patient with severe haemophilia A undergoing implantable venous access device placement was investigated. Initial KG-FS dilution resulted in a 10-20% FVIII loss; a further 25-30% loss occurred over 72 h in vials or syringes. With the double-pump, 1 h recovery was 35%, increasing to 80% by 24 h; the initial losses were because of the Y-infusion of a 10-fold larger volume of saline concomitantly with the FVIII. In vivo, CI resulted in stable FVIII activity levels within the target range. These in vitro results are important for the generation of CI guidelines for diluted KG-FS in the paediatric haemophilic population. That FVIII losses occur upon dilution and with the double-pump does not preclude use of diluted KG-FS. Indeed, stable FVIII levels were maintained when diluted KG-FS was administered by CI with the double-pump to a paediatric patient postsurgically.

[Prevention of infections and thromboses after splenectomy or because of functional loss of the spleen]. / Prävention von Infektionen und Thrombosen nach Splenektomie oder bei Funktionsverlust der Milz.

Overwhelming Post-Splenectomy Infection (OPSI or PSS), most frequently caused by encapsulated Gram-positive pathogens, is a complication after splenectomy. Reasons for splenectomy include trauma, or malignant and non-malignant hematologic diseases. OPSI-inducing bacteria are mainly Streptococcus pneumoniae and less frequently Haemophilus influenzae, Neisseria meningitides and Gram-negative bacilli. There exist very efficient--albeit often neglected--strategies, how to prevent infections in patients after splenectomy. These include vaccination, prophylactic antibiotics (always for 3 years during childhood and adolescence) and prompt antibiotic treatment, if an infection is suspected. Patients need to know the nature and likelihood of PSS and they should seek immediate medical attention if they become ill or febrile. Each patient should carry at all times a letter or card documenting the splenectomy. With these measures and precautions, the PSS-risk can be significantly reduced or at best be completely avoided.

Severe bleeding complications during antiepileptic treatment with valproic acid in children.

Valproic acid (VPA) is an antiepileptic drug frequently used in children. Although VPA can cause a variety of laboratory abnormalities affecting haemostasis, controversy exists about the clinical relevance of such haematological abnormalities. We report on 4 children with severe bleeding complications while on VPA therapy; two presented with intracranial bleeding, while two suffered from severe bleeding postoperatively. Diagnostic and therapeutic measures are discussed that help to avoid severe bleeding complications in children with VPA treatment.

Triple heterozygosity in the integrin alphaIIb subunit in a patient with Glanzmann's thrombasthenia.

We report triple heterozygosity in the integrin alpha(IIb) subunit in a 5-year-old Canadian girl with Glanzmann's thrombasthenia. The patient has a severe bleeding history possibly aggravated by low VWF suggestive of associated type 1 von Willebrand's disease. Platelet aggregation was absent or severely reduced for all physiologic agonists. Flow cytometry showed an approximately 4% residual surface expression of alpha(IIb)beta(3). Western blotting confirmed a low platelet expression of both subunits. PCR-SSCP and direct sequencing showed no abnormalities in the beta(3) gene, but revealed a G-->A transition at a splice site [IVS 19 (+1)] of exon 19 in the alpha(IIb) gene. Of maternal inheritance, the splice site mutation was associated with intermediate levels of alpha(IIb)beta(3) in carriers. Unexpectedly, two G-->A transitions were detected in exon 29 of the alpha(IIb) gene and led to V(951)-->M and A(958)-->T amino acid substitutions. Family studies using restriction enzymes showed that both exon 29 mutations were paternal in origin and cosegregated across three generations. Transient expression in which mutated alpha(IIb) was cotransfected with wild-type beta(3) in COS-7 cells showed that V(951)-->M gave a much reduced surface expression of alpha(IIb)beta(3) and a block in the maturation of pro-alpha(IIb). In contrast, the A(958) substitution appeared to be a novel polymorphism. Our studies highlight an unusual mixture of defects giving rise to severe bleeding in a child and describe the first pathological missense mutation affecting a C-terminal residue of the calf-2 domain of alpha(IIb).

The activity of the von Willebrand factor cleaving protease ADAMTS-13 in newborn infants.

BACKGROUND: Unusually large von Willebrand factor (VWF) multimers have been observed in patients with thrombotic microangiopathies (TMA), and absence of the VWF cleaving protease ADAMTS-13 activity is considered to be involved in the etiology of TMA. Increased amounts of large multimers of VWF have also been identified in neonates. OBJECTIVE: We assessed ADAMTS-13 activity in healthy neonates, children and adults to establish baseline levels. PATIENTS AND METHODS: Cord blood was collected from 38 full-term newborns; venous samples were taken from 15 neonates on day 2-3 of life. Seventeen children, 24 healthy adults and seven patients with TMA were studied as well. ADAMTS-13 activity was quantified by the binding of the subjects' plasma VWF to collagen before and after enzyme activation. The multimer distribution of VWF was also determined. RESULTS: Neonates and children had percentage ADAMTS-13 activity similar to adults. However, two groups were apparent in the cord blood samples: while 28/38 newborns had percentage activity within the normal range of healthy adults (102 +/- 3.0%), 10 had significantly lower percentage activity (53 +/- 1.1%; P < 0.0001) that normalized by day 2-3. The VWF multimer distribution was the same in all cord blood samples and was not different compared with children and adults. High-molecular-weight VWF multimers were significantly increased in the 2-3-day-old neonates and in TMA patients. CONCLUSIONS: Although ADAMTS-13 activity was similar in neonates compared with adults, 26% of neonates had mildly reduced activity. Further studies are needed to investigate the complex interaction of VWF production and secretion with its size control by ADAMTS-13 in different age groups.

Stroke in hemoglobin (SD) sickle cell disease with moyamoya: successful hydroxyurea treatment after cerebrovascular bypass surgery.

An 11-year-old boy with hemoglobin sickle disease (HbSD), bilateral stenosis of the intracranial carotid arteries, and moyamoya syndrome had recurrent ischemic strokes with aphasia and right hemiparesis. His parents (Jehovah's Witnesses) refused blood transfusions. After bilateral extracranial-intracranial (EC-IC) bypass surgery, hydroxyurea treatment increased hemoglobin F (HbF) levels to more than 30%. During a follow-up of 28 months, flow velocities in the basal cerebral arteries remained stable, neurologic sequelae regressed, and ischemic events did not recur. This is the first report of successful hydroxyurea treatment after bypass surgery for intracranial cerebral artery obstruction with moyamoya syndrome in sickle cell disease. The patient's religious background contributed to an ethically challenging therapeutic task. (Blood. 2001;97:2165-2167)