Mediastinal bleeding after cardiopulmonary bypass in pediatric patients

Forty-eight-hour cold-stored whole blood in paediatric cardiac surgery: Implications for haemostasis and blood donor exposures

BACKGROUND AND OBJECTIVES

Cold-stored whole blood (CS-WB) in paediatric cardiac surgery is making a resurgence, given its identified benefits compared to conventional blood component therapy (CT).

STUDY DESIGN AND METHODS

A single-centre retrospective study was conducted from January 2018 to October 2018 by including children <18 years of age undergoing cardiac surgery requiring cardiopulmonary bypass. ABO-compatible CS-WB from non-directed random donors was leukoreduced with platelet-sparing filters and compared with CT.

RESULTS

Fifty-seven patients (30, 53% CS-WB; 27, 47% CT) were studied. Patient demographics were similar, although CT patients were cooled to a lower intra-operative temperature. Blood product requirements 24 h post operation were less in the CS-WB group (11.1 vs. 26.7 mL/kg, p = 0.048). Twelve (40%) patients in the CS-WB cohort had more than one donor exposure versus 25 (93%) in the CT group (p < 0.001). CT patients compared to CS-WB patients had a greater decrease in pre-operative versus 48-h post-operative haemoglobin, platelets and prothrombin time. Patients who received CT compared to CS-WB had a trend towards higher median (interquartile range [IQR]) chest-tube output (mL/kg/h) in the first 4 h post cardiac intensive care unit (ICU) admission (2.1 [0.8, 3] vs. 1.6 [0.8, 2.2], p = 0.197). There was no difference in antifibrinolytic use, length of stay, sepsis, acute kidney injury or wound infection. Survival to discharge was similar.

CONCLUSION

CS-WB in paediatric cardiac surgery may reduce donor exposure and improve haemostatic balance. Future multi-centre prospective studies are needed to validate these findings and identify patients who would benefit from CS-WB in paediatric cardiac surgery.

Use of low titer O whole blood in infants and young children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Low titer group O whole blood (LTOWB) is commonly used for severe bleeding in trauma patients. LTOWB may also benefit young children requiring cardiac surgery with cardiopulmonary bypass (CPB) at risk of severe bleeding.

STUDY DESIGN AND METHODS

In this retrospective study, children <2 years old who underwent cardiac surgery with CPB were included. Comparisons were performed between those receiving component therapy (CT) versus those receiving LTOWB plus CT (LTOWB+CT). Outcomes included drainage tube (DT) output and total transfusion volumes. Optimization-based weighting was used for adjusted analyses between groups.

RESULTS

There were 117 patients transfused with only CT and 127 patients transfused with LTOWB+CT. In the LTOWB+CT group, 66 were Group non-O and 61 were Group O. Total transfusion volumes given from the start of the operation until the first 24 h in the cardiac intensive care unit was a median (IQR) 41 (10, 93) mL/kg in the CT group and 48 (28, 77) mL/kg in the LTOWB+CT group, (p = .28). Median (IQR) DT output was 22 (15-32) in CT versus 22 (16-28) in LTOWB+CT groups, (p = .27). There were no differences in death, renal failure and a composite of death and renal failure between the two groups, but there were statistically fewer re-explorations for bleeding in the LTOWB+CT group (p < .001).

CONCLUSIONS

The use of LTOWB appears to be safe in <2 years old undergoing cardiac surgery and may reduce re-explorations for severe bleeding. Large trials are needed to determine the efficacy and safety of LTOWB in this population with severe bleeding.

Plasma and Urinary FGF-2 and VEGF-A Levels Identify Children at Risk for Severe Bleeding after Pediatric Cardiopulmonary Bypass: A Pilot Study

Severe bleeding after cardiothoracic surgery with cardiopulmonary bypass (CPB) is associated with increased morbidity and mortality in adults and children. Fibroblast Growth Factor-2 (FGF-2) and Vascular Endothelial Growth Factor-A (VEGF-A) induce hemorrhage in murine models with heparin exposure. We aim to determine if plasma and urine levels of FGF-2 and VEGF-A in the immediate perioperative period can identify children with severe bleeding after CPB. We performed a prospective, observational biomarker study in 64 children undergoing CPB for congenital heart disease repair from June 2015 - January 2017 in a tertiary pediatric referral center. Primary outcome was severe bleeding defined as ≥ 20% estimated blood volume loss within 24-hours. Independent variables included perioperative plasma and urinary FGF-2 and VEGF-A levels. Analyses included comparative (Wilcoxon rank sum, Fisher's exact, and Student's t tests) and discriminative (receiver operator characteristic [ROC] curve) analyses. Forty-eight (75%) children developed severe bleeding. Median plasma and urinary FGF-2 and VEGF-A levels were elevated in children with severe bleeding compared to without bleeding (preoperative: plasma FGF-2 = 16[10-35] vs. 9[2-13] pg/ml; urine FGF-2= 28[15-76] vs. 14.5[1.5-22] pg/mg; postoperative: plasma VEGF-A = 146[34-379] vs. 53 [0-134] pg/ml; urine VEGF-A = 132 [52-257] vs. 45[0.1-144] pg/mg; all p < 0.05). ROC curve analyses of combined plasma and urinary FGF-2 and VEGF-A levels discriminated severe postoperative bleeding (AUC: 0.73-0.77) with mean sensitivity and specificity above 80%. We conclude that the perioperative plasma and urinary levels of FGF-2 and VEGF-A discriminate risk of severe bleeding after pediatric CPB.

Platelet Function Changes during Neonatal Cardiopulmonary Bypass Surgery: Mechanistic Basis and Lack of Correlation with Excessive Bleeding

Thrombocytopenia and platelet dysfunction induced by extracorporeal blood circulation are thought to contribute to postsurgical bleeding complications in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). In this study, we examined how changes in platelet function relate to changes in platelet count and to excessive bleeding in neonatal CPB surgery. Platelet counts and platelet P-selectin exposure in response to agonist stimulation were measured at four times before, during, and after CPB surgery in neonates with normal versus excessive levels of postsurgical bleeding. Relative to baseline, platelet counts were reduced in patients while on CPB, as was platelet activation by the thromboxane A2 analog U46619, thrombin receptor activating peptide (TRAP), and collagen-related peptide (CRP). Platelet activation by adenosine diphosphate (ADP) was instead reduced after platelet transfusion. We provide evidence that thrombocytopenia is a likely contributor to CPB-associated defects in platelet responsiveness to U46619 and TRAP, CPB-induced collagen receptor downregulation likely contributes to defective platelet responsiveness to CRP, and platelet transfusion may contribute to defective platelet responses to ADP. Platelet transfusion restored to baseline levels platelet counts and responsiveness to all agonists except ADP but did not prevent excessive bleeding in all patients. We conclude that platelet count and function defects are characteristic of neonatal CPB surgery and that platelet transfusion corrects these defects. However, since CPB-associated coagulopathy is multifactorial, platelet transfusion alone is insufficient to treat bleeding events in all patients. Therefore, platelet transfusion must be combined with treatment of other factors that contribute to the coagulopathy to prevent excessive bleeding.

Strategies for Prevention and Management of Bleeding Following Pediatric Cardiac Surgery on Cardiopulmonary Bypass: A Scoping Review

OBJECTIVE

We aimed to systematically describe, via a scoping review, the literature reporting strategies for prevention and management of mediastinal bleeding post pediatric cardiopulmonary bypass surgery.

DATA SOURCES

MEDLINE, EMBASE, PubMed, and Cochrane CENTRAL Register.

STUDY SELECTION

Two authors independently screened publications from 1980 to 2016 reporting the effect of therapeutic interventions on bleeding-related postoperative outcomes, including mediastinal drain loss, transfusion, chest re-exploration rate, and coagulation variables. Inclusions: less than 18 years, cardiac surgery on cardiopulmonary bypass.

DATA EXTRACTION

Data from eligible studies were extracted using a standard data collection sheet.

DATA SYNTHESIS

Overall, 299 of 7,434 screened articles were included, with observational studies being almost twice as common (n = 187, 63%) than controlled trials (n = 112, 38%). The most frequently evaluated interventions were antifibrinolytic drugs (75 studies, 25%), blood products (59 studies, 20%), point-of-care testing (47 studies, 16%), and cardiopulmonary bypass circuit modifications (46 studies, 15%). The publication rate for controlled trials remained constant over time (4-6/yr); however, trials were small (median participants, 51; interquartile range, 57) and overwhelmingly single center (98%). Controlled trials originated from 22 countries, with the United States, India, and Germany accounting for 50%. The commonest outcomes were mediastinal blood loss and transfusion requirements; however, these were defined inconsistently (blood loss being reported over nine different time periods). The majority of trials were aimed at bleeding prevention (98%) rather than treatment (10%), nine studies assessed both.

CONCLUSIONS

Overall, this review demonstrates small trial sizes, low level of evidence, and marked heterogeneity of reported endpoints in the included studies. The need for more, higher quality studies reporting clinically relevant, comparable outcomes is highlighted. Emerging fields such as the use of coagulation factor concentrates, goal-directed guidelines, and anti-inflammatory therapies appear to be of particular interest. This scoping review can potentially guide future trial design and form the basis for therapy-specific systematic reviews.

Validation of a definition of excessive postoperative bleeding in infants undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVE

To derive and validate an objective definition of postoperative bleeding in neonates and infants undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

Using a retrospective cohort of 124 infants and neonates, we included published bleeding definitions and cumulative chest tube output over different postoperative periods (eg, 2, 12, or 24 hours after intensive care unit admission) in a classification and regression tree model to determine chest tube output volumes that were associated with red blood cell transfusions and surgical re-exploration for bleeding in the first 24 hours after intensive care unit admission. After the definition of excessive bleeding was determined, it was validated via a prospective cohort of 77 infants and neonates.

RESULTS

Excessive bleeding was defined as ≥7 mL/kg/h for ≥2 consecutive hours in the first 12 postoperative hours and/or ≥84 mL/kg total for the first 24 postoperative hours and/or surgical re-exploration for bleeding or cardiac tamponade physiology in the first 24 postoperative hours. Excessive bleeding was associated with longer length of hospital stay, increased 30-day readmission rate, and increased transfusions in the postoperative period.

CONCLUSIONS

The proposed standard definition of excessive bleeding is based on readily obtained objective data and relates to important early clinical outcomes. Application and validation by other institutions will help determine the extent to which our specialty should consider this definition for both clinical investigation and quality improvement initiatives.

Overview of Heparin and Protamine Management and Dosing Regimens in Pediatric Cardiac Surgical Patients

Compared with adults, infants and children who undergo cardiopulmonary bypass for cardiac surgery present with a myriad of anticoagulation considerations. Inadequate anticoagulation during cardiopulmonary bypass may cause “subclinical” or “overt” thrombosis, while effective anticoagulation decreases excessive bleeding and transfusions. Current strategies for heparinization and its neutralization in pediatric patients undergoing congenital heart repair requiring cardiopulmonary bypass are examined. The coagulation system of the neonate and infant is immature and is further weakened by congenital heart disease. Changes in coagulation and fibrinolytic activity occur during cardiopulmonary bypass as a result of hemodilution and exposure of the blood to the extracorporeal circuit. Adequate anticoagulation is essential to minimize the thrombin generation that will result. The extent of excessive thrombin formation in pediatric patients undergoing cardiopulmonary bypass is better appreciated today than in the past, but no controlled study defines the optimal dose or technique for heparin dosing in these patients. Heparin concentration may even fall to 1.5 U/mL during cardiopulmonary bypass. However, the activated clotting time and heparin concentration correlate poorly. The ideal method to achieve adequate thrombin inhibition is unknown. Additionally, the dangers of excessive protamine are becoming more apparent. Heparin continues to be the most effective agent to achieve anticoagulation and protamine the most effective agent to neutralize it. A technique for heparin and protamine dosing with determination of heparin concentrations, may remove many variables associated with pediatric cardiac surgery that requires cardiopulmonary bypass and may provide clinicians with new therapies to achieve better anticoagulation for patients and consequently better outcomes.

Effect of 22q11.2 deletion on bleeding and transfusion utilization in children with congenital heart disease undergoing cardiac surgery

BACKGROUND

Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD. The deleted segment of chromosome 22q11.2 encompasses the gene encoding glycoprotein (GP) Ibβ, which is required for expression of the GPIb-V-IX complex on the platelet surface, where it functions as the receptor for von Willebrand factor (VWF). Binding of GPIb-V-IX to VWF is important for platelets to initiate hemostasis. It is not known whether hemizygosity for the gene encoding GPIbβ increases the risk for bleeding following cardiac surgery for patients with 22q11.2 DS.

METHODS

We performed a case-control study of 91 pediatric patients who underwent cardiac surgery with cardiopulmonary bypass from 2004 to 2012 at Children's Hospital of Wisconsin.

RESULTS

Patients with 22q11.2 DS had larger platelets and lower platelet counts, bled more excessively, and received more transfusion support with packed red blood cells in the early postoperative period relative to control patients.

CONCLUSION

Presurgical genetic testing for 22q11.2 DS may help to identify a subset of pediatric cardiac surgery patients who are at increased risk for excessive bleeding and who may require more transfusion support in the postoperative period.

Association of blood products administration during cardiopulmonary bypass and excessive post-operative bleeding in pediatric cardiac surgery

Our objectives were to study risk factors and post-operative outcomes associated with excessive post-operative bleeding in pediatric cardiac surgeries performed using cardiopulmonary bypass (CPB) support. A retrospective observational study was undertaken, and all consecutive pediatric heart surgeries over 1 year period were studied. Excessive post-operative bleeding was defined as 10 ml/kg/h of chest tube output for 1 h or 5 ml/kg/h for three consecutive hours in the first 12 h of pediatric cardiac intensive care unit (PCICU) stay. Risk factors including demographics, complexity of cardiac defect, CPB parameters, hematological studies, and post-operative morbidity and mortality were evaluated for excessive bleeding. 253 patients were studied, and 107 (42 %) met the criteria for excessive bleeding. Bayesian model averaging revealed that greater volume of blood products transfusion during CPB was significantly associated with excessive bleeding. Multiple logistic regression analysis of blood products transfusion revealed that increased volume of packed red blood cells (PRBCs) administration for CPB prime and during CPB was significantly associated with excessive bleeding (p = 0.028 and p = 0.0012, respectively). Proportional odds logistic regression revealed that excessive bleeding was associated with greater time to achieve negative fluid balance, prolonged mechanical ventilation, and duration of PCICU stay (p < 0.001) after adjusting for multiple parameters. A greater volume of blood products administration, especially PRBCs transfusion for CPB prime, and during the CPB period is associated with excessive post-operative bleeding. Excessive bleeding is associated with worse post-operative outcomes.

Continuous or discontinuous tranexamic acid effectively inhibits fibrinolysis in children undergoing cardiac surgery with cardiopulmonary bypass

Tranexamic acid is given continuously or discontinuously as an anti-fibrinolytic therapy during cardiac surgery, but the effects on fibrinolysis parameters remain poorly investigated. We sought to assess the effects of continuous and discontinuous tranexamic acid on fibrinolysis parameters in children undergoing cardiac surgery with cardiopulmonary bypass (CPB). Children requiring cardiac surgery or repeat surgery by sternotomy with CPB for congenital heart disease were randomized to receive either continuous or discontinuous tranexamic acid. Blood tranexamic acid, D-dimers, tissue plasminogen activator (tPA), tPA-plasminogen activator inhibitor 1 (tPA-PAI1) complexes, fibrinogen and fibrin monomers were measured and compared to values obtained from children who did not receive tranexamic acid. Tranexamic acid inhibited the CPB-induced increase in D-dimers, with a similar potency between continuous and discontinuous regimens. Time courses for tPA, fibrin monomers, and fibrinogen were also similar for both regimen, and there was a significant difference in tPA-PAI1 complex concentrations at the end of surgery, which may be related to a significantly higher tranexamic acid concentration. Continuous and discontinuous regimen are suitable for an effective inhibition of fibrinolysis in children undergoing cardiac surgery with CPB, but the continuous regimen was previously shown to be more effective to maintain stable tranexamic acid concentrations.

Implementation of a transfusion algorithm to reduce blood product utilization in pediatric cardiac surgery

AIM

The goal of this project is to measure the impact of standardization of transfusion practice on blood product utilization and postoperative bleeding in pediatric cardiac surgery patients.

BACKGROUND

Transfusion is common following cardiopulmonary bypass (CPB) in children and is associated with increased mortality, infection, and duration of mechanical ventilation. Transfusion in pediatric cardiac surgery is often based on clinical judgment rather than objective data. Although objective transfusion algorithms have demonstrated efficacy for reducing transfusion in adult cardiac surgery, such algorithms have not been applied in the pediatric setting.

METHODS

This quality improvement effort was designed to reduce blood product utilization in pediatric cardiac surgery using a blood product transfusion algorithm. We implemented an evidence-based transfusion protocol in January 2011 and monitored the impact of this algorithm on blood product utilization, chest tube output during the first 12 h of intensive care unit (ICU) admission, and predischarge mortality.

RESULTS

When compared with the 12 months preceding implementation, blood utilization per case in the operating room odds ratio (OR) for the 11 months following implementation decreased by 66% for red cells (P = 0.001) and 86% for cryoprecipitate (P < 0.001). Blood utilization during the first 12 h of ICU did not increase during this time and actually decreased 56% for plasma (P = 0.006) and 41% for red cells (P = 0.031), indicating that the decrease in OR transfusion did not shift the transfusion burden to the ICU. Postoperative bleeding, as measured by chest tube output in the first 12 ICU hours, did not increase following implementation of the algorithm. Monthly surgical volume did not change significantly following implementation of the algorithm (P = 0.477). In a logistic regression model for predischarge mortality among the nontransplant patients, after accounting for surgical severity and duration of CPB, use of the transfusion algorithm was associated with a 0.247 relative risk of mortality (P = 0.013).

CONCLUSIONS

These results indicate that introduction of an objective transfusion algorithm in pediatric cardiac surgery significantly reduces perioperative blood product utilization and mortality, without increasing postoperative chest tube losses.

A systematic review of the use of antifibrinolytic agents in pediatric surgery and implications for craniofacial use

A systematic review aimed to evaluate the efficacy and safety of aprotinin, epsilon-aminocaproic acid (EACA), and tranexamic acid (TXA) in reducing perioperative blood loss, risk for transfusion, and total perioperative transfusion volume in major pediatric surgery. Medline, Embase, and Cochrane Reviews were searched for relevant articles published from January 1990 to January 2012. Additional studies were identified by cross-referencing citations and extracting data from recent published reviews. Data were recorded and analyzed using Cochrane's RevMan5.1 software. Thirty-four studies were included in this review of which 21 provided level 1b evidence, 11 were level 2b, and two were level 3b. As compared to control groups, antifibrinolytics reduced perioperative blood loss by standardized mean difference (SMD) of -0.70 (-0.89, -0.50; p<0.00001), total transfusion volume by SMD of -0.78 (-0.95, -0.61; p < 0.00001), and Odds Ratio (OR) for transfusion was 0.39 (0.23, 0.64; p=0.002). The OR for adverse events attributable to treatment was not statistically significant across groups (OR = 0.96; p = 0.58). Antifibrinolytics are effective in reducing blood loss and transfusion requirements in major pediatric surgery. TXA and EACA also appear to have reasonable side-effect profiles. Application to craniofacial surgery is promising, though further investigation is necessary.

Plasmin generation and fibrinolysis in pediatric patients undergoing cardiopulmonary bypass surgery

This prospective, single-centre cohort study aimed to evaluate plasmin generation and fibrinolysis during and after cardiopulmonary bypass (CPB) surgery in a cohort of children up to 6 years of age. Blood samples were drawn at eight time points: after induction of anesthesia, before unfractionated heparin (UFH), after UFH, after initiation of bypass, before protamine, after protamine, after chest closure, and 6 h after chest closure. The study identified an increase in fibrinolysis during CPB and particularly up to 6 h afterward in children. This could be the mechanism for the significant bleeding events observed in this young population after CPB. This study establishes the foundation for future studies in this area, particularly those focusing on clinical outcomes after CPB surgery.

Recombinant activated factor VII for hemorrhage after pediatric cardiac surgery

Postoperative bleeding is a common complication after pediatric cardiac surgery. Use of recombinant activated factor VII for intractable hemorrhage after cardiac, pediatric, and neurosurgery has been shown to decrease postoperative bleeding, but data in children are limited. This retrospective study analyzed 20 children <15 years-old who underwent cardiac surgery and received recombinant activated factor VII for refractory postoperative hemorrhage. All patients underwent mediastinal reexploration before recombinant activated factor VII was administered as a bolus dose over 2–3 min as rescue therapy. If no significant decrease in chest tube drainage was observed, the dose was repeated after an interval of at least 2 h. The median dose of recombinant activated factor VII administered per bleeding episode was 83.33 µg·kg−1 (range, 72.47–87.50 µg·kg−1), and the dose per patient was 154.16 µg·kg−1 (range, 93.06–180.52 µg·kg−1). The median number of doses found to be effective in these children was 1.76. There were significant decreases in mediastinal chest tube drainage and the volume of packed red blood cells, platelet concentrates, and cryoprecipitate administered after recombinant activated factor VII. No complications were observed during the therapy.

Hemostatic response in paediatric patients undergoing cardiopulmonary bypass surgery

This prospective, single-center cohort study aimed to evaluate the hemostatic response during and after Cardiopulmonary Bypass (CPB) surgery in a large cohort of children up to 6 years of age. Blood samples were drawn at eight time points: post-induction of anesthesia, pre-unfractionated heparin (UFH), post-UFH, post-initiation of bypass, pre-protamine, post-protamine, post-chest-closure, and 6 h post-chest-closure. As expected, all measures of the UFH effect increased significantly post-UFH bolus and decreased post-protamine administration. However, thrombin generation remained inhibited compared to baseline values despite the post-UFH reversal by protamine. We also demonstrate that residual UFH effect is not responsible for the ongoing inhibition of thrombin observed post-protamine administration. The significant increase in both free and total tissue factor pathway inhibitor levels during the CPB surgery might contribute to the persistent thrombin generation/endogenous thrombin potential inhibition post-protamine administration. This study makes a significant and novel contribution by investigating the physiological mechanisms behind the degree of thrombin inhibition by UFH and the residual levels of thrombin inhibition that continue despite protamine reversal and provides a new foundation for future interventional studies in the setting of paediatric CPB surgery.

Treatment and monitoring of coagulation abnormalities in children undergoing heart surgery

Bleeding is a considerable clinical problem during and after pediatric heart surgery. While the primary cause of bleeding is surgical trauma, its treatment is often complicated by the presence of coagulopathy. The principle causes of coagulopathy are discussed to provide a context for treatment. The role of laboratory and point of care tests, which aim to identify the cause of bleeding in the individual patient, is also discussed. An attempt is made to examine the current evidence for available therapies, including use of blood products and, more recently proposed, approaches based on human or recombinant factor concentrates.

The Role of Thromboelastography in Directing Blood Product Usage in Infant Open Heart Surgery

Objective

Thromboelastography (TEG) measures the dynamics of clot formation in whole blood and provides data that can guide specific blood component therapy. This study analyzed whether the implementation of TEG affected blood product utilization and overall hemostasis in infants (6 months and younger) undergoing open heart surgery.

Methods

TEG values measured include R (time to fibrin formation), angle (fibrinogen formation), and MA (platelet function). Blood product usage, TEG values, and operative parameters were collected during surgery on 112 consecutive infants (66 acyanotic) undergoing open heart surgery within the first 6 months of life. Controls consisted of chart data on 70 consecutive patients (57 acyanotic) undergoing the same surgical procedures before implementation of TEG (pre-TEG).

Results

Using TEG, the pattern of blood product utilization changed. Compared with the pre-TEG era, TEG era patients demonstrated a significant increase in fresh frozen plasma usage intraoperatively (4.74 vs. 1.83 mL/kg; P < 0.001) and reduced postoperative use of platelets (1.69 vs. 3.74 mL/kg; P = 0.006) and cryoprecipitate (0.89 vs. 1.95 mL/kg; P = 0.149). Chest tube drainage was significantly reduced at 1, 2, and 24 hours in the TEG group. TEG angle and MA measurements suggest that fibrinogen and platelets of cyanotic patients are more sensitive to hemodilution than the acyanotic patients.

Conclusions

TEG allows for proactive, goal-directed blood component therapy with improved postoperative hemostasis in infants undergoing cardiopulmonary bypass.

The effect of aprotinin, tranexamic acid, and aminocaproic acid on blood loss and use of blood products in major pediatric surgery: a meta-analysis

OBJECTIVE

Aprotinin reduces the blood loss and transfusion of blood products in children undergoing major surgery. Aprotinin has been associated with severe side effects in adults, and tranexamic acid and aminocaproic acid have been found to be safer alternatives in adults. This systematic review addresses the question of whether tranexamic acid and aminocaproic acid are equally effective as aprotinin for reducing blood loss and transfusion in children undergoing major surgery.

DATA SOURCES

A systematic review of the literature was conducted to identify all randomized controlled trials of aprotinin, tranexamic acid, and aminocaproic acid involving children undergoing cardiac or scoliosis surgery.

STUDY SELECTION AND DATA EXTRACTION

Twenty-three cardiac studies, totaling 1893 patients, met the inclusion criteria. None of the studies directly compared aprotinin to an alternative antifibrinolytic. Five scoliosis studies, totaling 207 patients, met the inclusion criteria. Data on blood loss and use of blood products in the first 24 postoperative hours were extracted. Only homogenously distributed outcomes were pooled.

DATA SYNTHESIS

Tranexamic acid showed a homogeneously distributed reduction of blood loss by 11 mL/kg (95% confidence interval [CI] 9-13 mL/kg). Outcomes of blood loss reduction by aprotinin and aminocaproic acid were too heterogeneously distributed to be pooled, so the effect on blood loss could not be evaluated. Both aprotinin and tranexamic acid significantly reduced packed red cell transfusion (4 mL/kg, 95% CI 2-7 mL/kg and 7 mL/kg, 95% CI 5-10 mL/kg, respectively). Type of antifibrinolytic was not a determining factor that explained differences in outcome among trials in a meta-regression analysis. In the scoliosis studies, aprotinin and tranexamic acid significantly reduced blood loss compared with placebo (385 mL, 95% CI 727-42 mL and 682 mL, 95% CI 1149-214 mL, respectively).

CONCLUSIONS

There is no evidence that suggests that, compared with aprotinin, alternative antifibrinolytics such as tranexamic acid were less effective in reducing blood loss in major pediatric surgery.

Reconstituted fresh whole blood improves clinical outcomes compared with stored component blood therapy for neonates undergoing cardiopulmonary bypass for cardiac surgery: a randomized controlled trial

OBJECTIVE

This study compared the effects of reconstituted fresh whole blood against standard blood component therapy in neonates undergoing cardiac surgery.

METHODS

Patients less than 1 month of age were randomized to receive either reconstituted fresh whole blood (n = 31) or standard blood component therapy (n = 33) to prime the bypass circuit and for transfusion during the 24 hours after cardiopulmonary bypass. Primary outcome was chest tube drainage; secondary outcomes included transfusion needs, inotrope score, ventilation time, and hospital length of stay.

RESULTS

Patients who received reconstituted fresh whole blood had significantly less postoperative chest tube volume loss per kilogram of body weight (7.7 mL/kg vs 11.8 mL/kg; P = .03). Standard blood component therapy was associated with higher inotropic score (6.6 vs 3.3; P = .002), longer ventilation times (164 hours vs 119 hours; P = .04), as well as longer hospital stays (18 days vs 12 days; P = .006) than patients receiving reconstituted fresh whole blood. Of the different factors associated with the use of reconstituted fresh whole blood, lower platelet counts at 10 minutes and at the end of cardiopulmonary bypass, older age of cells used in the prime and throughout bypass, and exposures to higher number of allogeneic donors were found to be independent predictors of poor clinical outcomes.

CONCLUSIONS

Reconstituted fresh whole blood used for the prime, throughout cardiopulmonary bypass, and for all transfusion requirements within the first 24 hours postoperatively results in reduced chest tube volume loss and improved clinical outcomes in neonatal patients undergoing cardiac surgery.

Minimizing perioperative blood loss and transfusions in children

PURPOSE

To summarize the physiology and pathophysiology relevant to perioperative blood loss in children. Strategies to reduce blood losses are reviewed.

METHODS

The literature was reviewed using the electronic library PUBMED and the Cochrane Database of Systematic Reviews. Relevant studies published in English or French with an English abstract are included. The following keywords were used: children, blood transfusion, surgical blood loss, erythropoietin, autologous blood, red blood cell saver, normovolemic hemodilution, desmopressin, aminocaproic acid, tranexamic acid, aprotinin, cardiac surgery, liver transplantation and scoliosis surgery.

MAIN FINDINGS

For patients with idiopathic scoliosis, predonation with or without the addition of erythropoietin is a safe and effective way to avoid the use of allogenic blood products. For open heart procedures: whole blood of less than 48 hr is helpful for children of less than two years of age undergoing complex procedures; tranexamic acid may be helpful for cyanotic heart disease and, to a lesser degree, for reoperations; while anti-kallikrein blood levels of aprotinin may both reduce the need for allogenic blood transfusions and improve postoperative oxygenation in infants.

CONCLUSION

Reducing perioperative allogenic blood transfusions is possible in pediatric patients provided that prophylactic measures are adapted to age, disease and type of surgery.

Elective administration in infants of low-dose recombinant activated factor VII (rFVIIa) in cardiopulmonary bypass surgery for congenital heart disease does not shorten time to chest closure or reduce blood loss and need for transfusions: a randomized, double-blind, parallel group, placebo-controlled study of rFVIIa and standard haemostatic replacement therapy versus standard haemostatic replacement therapy

We investigated the effectiveness of prophylactic administration of recombinant activated factor VII (rFVIIa) for cardiopulmonary bypass surgery in children under 1 year old with congenital heart disease (CHD) in a double-blinded, placebo-controlled study. The rFVIIa dose was 40 microg/kg and all patients also received standard haemostatic replacement therapy. The primary endpoint was the time to chest closure from neutralization of heparin with protamine sulphate as this could be most objectively and accurately measured during surgery. Secondary endpoints were volumes of transfused blood, platelet concentrates and fresh-frozen plasma. All adverse events were recorded. In the intention-to-treat analysis there were 76 patients (40 in rFVIIa group and 36 in placebo group). The demographics and severity of CHD were similar in both groups. No benefit of rFVIIa prophylaxis was found in the time to chest closure, which was significantly prolonged in the rFVIIa group (rFVIIa mean +/- SE, 98.8 +/- 27.27 versus 55.3 +/- 29.15, P = 0.0263). In the 41 patients available for a follow-up visit 6 weeks after discharge, the chest closure time was also prolonged in the rFVIIa group (P = 0.0515). There were no significant differences in the secondary endpoints. Adverse events were similar in both groups.

Which may be effective to reduce blood loss after cardiac operations in cyanotic children: tranexamic acid, aprotinin or a combination?

BACKGROUND

Children with cyanotic heart disease undergoing cardiac surgery in which cardiopulmonary bypass is used are at increased risk of postoperative bleeding. In this study, the authors investigated the possibility of reducing postoperative blood loss by using aprotinin and tranexamic acid alone or a combination of these two agents.

METHODS

In a prospective, randomized, blind study, 100 children undergoing cardiac surgery were investigated. In group 1 (n = 25) patients acted as the control and did not receive either study drugs. In group 2 (n = 25) patients received aprotinin (30.000 KIU.kg(-1) after induction of anesthesia, 30.000 KIU.kg(-1) in the pump prime and 30.000 KIU.kg(-1) after weaning from bypass). In group 3 (n = 25) patients received tranexamic acid (100 mg.kg(-1) after induction of anesthesia, 100 mg.kg(-1) in the pump prime and 100 mg.kg(-1) after weaning from bypass). In group 4 (n = 25) patients received a combination of the two agents in the same manner. Total blood loss and transfusion requirements during the period from protamine administration until 24 h after admission to the intensive care unit were recorded. In addition, hemoglobin, platelet counts and coagulation studies were recorded.

RESULTS

Postoperative blood loss was significantly higher in the control group (group 1) compared with children in other groups who were treated with aprotinin, tranexamic acid or a combination of the two agents (groups 2, 3 and 4) during the first 24 h after admission to cardiac intensive care unit (40 +/- 18 ml.kg(-1).24 h(-1), aprotinin; 35 +/- 16 ml.kg(-1).24 h(-1), tranexamic acid; 34 +/- 19 ml.kg(-1).24 h(-1), combination; 35 +/- 15 ml.kg(-1).24 h(-1)). The total transfusion requirements were also significantly less in the all treatment groups. Time taken for sternal closure was longer in the control group (68 +/- 11 min) compared with treatment groups 2, 3 and 4, respectively (40 +/- 18, 42 +/- 11, 42 +/- 13 min, P < 0.05). The coagulation parameters were not found to be significantly different between the three groups.

CONCLUSIONS

Our results suggested that both agents were effective to reduce postoperative blood loss and transfusion requirements in patients with cyanotic congenital heart disease. However, the combination of aprotinin and tranexamic acid did not seem more effective than either of the two drugs alone.

Variability of plasma aprotinin concentrations in pediatric patients undergoing cardiac surgery

OBJECTIVES

Infants and children undergoing cardiopulmonary bypass for repair of congenital heart defects are at substantial risk for excessive bleeding, contributing greatly to morbidity and mortality. Aprotinin significantly reduces bleeding and transfusion requirements in adults but is of indeterminate value for pediatric patients. The aim of this study was to determine plasma aprotinin concentrations in these patients with a functional aprotinin assay.

METHODS

Thirty patients less than 16 years of age scheduled for cardiac surgery with aprotinin were enrolled. Aprotinin was administered as a 25,000 KIU/kg bolus, 35,000 KIU/kg cardiopulmonary bypass prime, and 12,500 KIU.kg(-1).h(-1) continuous infusion. Blood samples for aprotinin concentrations (kallikrein-inhibiting units/milliliter) were obtained before aprotinin; 5 minutes post-bolus; 5 minutes after cardiopulmonary bypass initiation; 30 and 60 minutes on cardiopulmonary bypass; on discontinuation of aprotinin; 1 hour after aprotinin discontinuation; and 4 hours after permanent separation from cardiopulmonary bypass. For analysis, patients were grouped according to weight (<10 kg, 10-20 kg, >20 kg). Differences between weight groups were assessed using an exact test for categoric variables and 1-way analysis of variance for continuous variables.

RESULTS

Aprotinin concentrations differed significantly across weight groups. Five minutes after aprotinin bolus and initiation of cardiopulmonary bypass, there was significant correlation between weight and aprotinin concentration (r =.57, P =.003; r =.69, P =.001, respectively).

CONCLUSION

A functional assay reveals significant variability in aprotinin concentration for pediatric patients using current weight-based aprotinin dosing. Additional investigation is necessary to determine target aprotinin concentration dosing regimens to provide better efficacy.

Changes in hemostasis during pediatric heart surgery: impact of a biocompatible heparin-coated perfusion system

BACKGROUND

This study describes the response in hemostasis during open-heart surgery with cardiopulmonary bypass (CPB) in children (<== 10 kg) and tests the hypothesis that the use of a biocompatible perfusion system, in comparison with a conventional system, causes less hemostatic activation.

METHODS

Prospective, randomized, controlled clinical study. Forty consecutive children <== 10 kg were included and divided into two groups: group bioc. (n = 19) treated with a fully heparin-coated system, centrifugal pump, and a closed circuit, and group conv. (n = 21) treated with an uncoated system, roller pump, and a hard shell venous reservoir. Concentrations of plasma thrombin-antithrombin (TAT), D-dimer, tissue plasminogen activator antigen (t-PA ag), and the complex consisting of tissue plasminogen activator and its inhibitor plasminogen activator inhibitor-1 (t-PA-PAI-1) were measured.

RESULTS

The biochemical variables measured increased significantly in both groups during the study period. There was less activation of fibrinolysis during cardiopulmonary bypass (t-PA ag: p = 0.009) in patients treated with the biocompatible perfusion system than in patients treated with the conventional system. A trend in favor of the biocompatible system based on the D-dimer and TAT data (p = 0.07 for both measurements) was observed but no significant intergroup differences regarding these variables or t-PA-PAI-1 were found.

CONCLUSIONS

Open-heart surgery with cardiopulmonary bypass in children (<== 10 kg) causes transient activation of the coagulation and fibrinolytic systems. This study demonstrates that the use of a biocompatible perfusion system results in a lower extent of activation of fibrinolysis during CPB than the use of a conventional system.

Fresh frozen plasma in the pediatric pump prime: a prospective, randomized trial

BACKGROUND

The aim of this study was to determine whether the use of fresh frozen plasma (FFP) in the infant pump prime can avoid dilution of fibrinogen, decrease the need for blood product transfusion after bypass, and decrease exposure to donor blood products.

METHODS

Twenty infants weighing less than 8 kg were prospectively randomized to receive either 1 U of FFP (10 patients) or no FFP (10 patients) in the pump prime. Mean age (4.2 +/- 2.8 months), weight (4.3 +/- 1.1 kg), total prime volume (641 +/- 96 ml), cardiopulmonary bypass time, cross-clamp time, lowest temperature on bypass, and preoperative coagulation parameters did not differ between the two groups.

RESULTS

At the end of bypass, the mean fibrinogen level was significantly higher in the FFP than the no FFP group (123 +/- 20 versus 58 +/- 17 mg/dL; p < 0.0001), whereas the mean platelet count did not differ (60 +/- 25 versus 52 +/- 26 K/mm(3); p = 0.5). Patients in the FFP group received significantly fewer units of cryoprecipitate (0.4 +/- 0.8 versus 2.0 +/- 0.9 U/patient; p < 0.001), and had a mean total donor exposure of 4.1 +/- 1.5 U/patient versus 5.4 +/- 1.4 U/patient in the no FFP group (p = 0.06). The mean chest tube output over the first 24 hours did not differ between groups.

CONCLUSIONS

The use of FFP in the pump prime significantly limited dilutional hypofibrinogenemia, decreased the transfusion of cryoprecipitate after bypass, and tended to decrease the overall mean patient exposure to blood products.

Blood loss in infants and children for open heart operations: albumin 5% versus fresh-frozen plasma in the prime

BACKGROUND

Infants and children undergoing cardiopulmonary bypass become substantially hemodiluted secondary to the volume used to prime the oxygenator. Fresh-frozen plasma has been included in the prime to lessen dilution of clotting factors and correspondingly minimize blood loss and transfusions.

METHODS

We prospectively randomized 56 patients weighing 10 kg or less who required cardiopulmonary bypass to receive either one unit of fresh-frozen plasma or 200 mL of albumin 5% in the prime. After protamine administration, samples for prothrombin time, fibrinogen, platelet count, and thromboelastogram were obtained. Mediastinal chest tube drainage and transfusion requirements were documented.

RESULTS

There were no significant differences between groups regarding demographic or surgical characteristics. Blood loss during the first 24 hours was similar in both groups, but total transfusions were significantly greater in those who received fresh-frozen plasma instead of albumin 5% in the prime (8.0 +/- 4.2 versus 6.1 +/- 4.5 U, respectively; p = 0.035). Post hoc analyses suggest that for cyanotic patients and patients undergoing complex operations, fresh-frozen plasma in the prime results in less blood loss than albumin 5%.

CONCLUSIONS

Substitution of albumin 5% for fresh-frozen plasma in the prime of acyanotic patients weighing 10 kg or less who undergo noncomplex operations requiring cardiopulmonary bypass significantly reduces perioperative transfusions without increasing blood loss. Further investigation is needed to determine whether increased blood loss is associated with increased transfusions when albumin 5% is substituted for fresh-frozen plasma in the prime of infants and children who are cyanotic or undergoing complex operations.

Significant merits of a fibrin sealant in the presence of coagulopathy following paediatric cardiac surgery: randomised controlled trial

OBJECTIVES

The efficacy of a fibrin sealant in paediatric cardiac surgery has been demonstrated. However, its effectiveness in the presence of significant untreated coagulopathy has not been addressed. This study was designed to investigate the role of the topical application of a fibrin sealant, Beriplast P (BP), in the presence of coagulopathy following paediatric cardiac surgery.

METHODS

After confirming the presence of significant post-bypass coagulopathy, patients undergoing repair of congenital heart defects using cardiopulmonary bypass were randomised to the use of BP (group BP) or no intervention (group C). BP was applied over suture lines and microvascular bleeding sites. Criteria for transfusion of blood and blood products were standardised for both groups. Outcome variables were: (1) post-operative bleeding; (2) transfusion of blood and blood products; (3) theatre time to achieve haemostasis; (4) ventilation time, intensive therapy unit (ITU) and hospital stay.

RESULTS

Fifty-two patients (n=26 in each group), aged 3 days to 17.4 years were recruited. There were no hospital deaths and no significant differences in demographic or intraoperative variables that might have affected the chosen endpoints. After protamine, all patients in both groups had significant coagulopathy (P< or = 0.05 versus baseline). There were fewer patients receiving transfusions of fresh frozen plasma (FPP) in the intervention group, when compared to the control group (P< or = 0.05). Patients receiving BP spent less time in theatre to achieve haemostasis (P< or = 0.05), had a lesser amount of bleeding intraoperatively (P< or = 0.01), at 4h (P< or = 0.05) and at 24h (P< or = 0.05), required a lower amount of transfusions of red cells (P< or = 0.01), FPP (P< or = 0.05) and platelets (P< or = 0.05). There were no differences in ventilation time, length of stay in ITU or in hospital.

CONCLUSIONS

Even in the presence of significant coagulopathy, intraoperative use of fibrin sealant in paediatric cardiac surgery reduces the amount of bleeding and need for transfusions of blood and blood products. The theatre time necessary to achieve haemostasis is also significantly reduced. These findings have a potential to improve clinical outcomes and enhance cost benefits.

BioGlue surgical adhesive impairs aortic growth and causes anastomotic strictures

BACKGROUND

BioGlue surgical adhesive (CryoLife, Inc, Kennesaw, GA) is currently being used to secure hemostasis at cardiovascular anastomoses in adults. Interference with vessel growth would preclude its use during congenital heart surgery. The purpose of this study was to determine if BioGlue reinforcement of aortic anastomoses impairs vessel growth and causes strictures.

METHODS

Ten 4-week-old piglets (8.0 +/- 1.4 kg) underwent primary aorto-aortic anastomoses. Five piglets were randomly assigned to anastomotic reinforcement with BioGlue. After a 7-week growth period, the aortas were excised for morphometric analysis and histopathology.

RESULTS

Weight gains were similar in both groups. In BioGlue animals, however, aortic circumference increased only 1.5 +/- 0.8 mm (versus 2.7 +/- 0.8 mm in controls; p = 0.054). BioGlue animals developed a 33.9% stenosis of the aortic lumen area (versus 3.7% in controls, p = 0.038). Adventitial changes reflecting tissue injury and fibrosis were present in all BioGlue animals versus none of the control animals (p = 0.008).

CONCLUSIONS

BioGlue reinforcement impairs vascular growth and causes stricture when applied circumferentially around an aorto-aortic anastomosis. This adhesive should not be used on cardiovascular anastomoses in pediatric patients.

Rational use of blood products

Blood product transfusions can be life saving and must be considered in the supportive care of children of any age with underlying oncological or haematological problems, as well as after major surgery or after serious trauma. Paediatric transfusions are particularly challenging because life-long effects of transfusion complications are more durable and serious in children than in adults, in whom the median age at transfusion is >70 years (Tynell E, Norda R, Shanwell A, Björkman A. Long-term survival in transfusion recipients in Sweden, 1993. Transfusion 2001, 41, 251-255). While the general indications for transfusions in paediatric patients are similar to adults, the threshold, volumes and infusion rates for transfusions vary with age. In this Update, we discuss current blood products, then suggest transfusion "triggers" in major surgery and haematological and oncologic practice. Finally, future developments and new possibilities are considered.

Erythropoietin therapy and preoperative autologous blood donation in children undergoing open heart surgery

We assessed the feasibility and efficacy of subcutaneous erythropoietin alpha (EPO) therapy and preoperative autologous blood donation (ABD) in children undergoing open heart surgery. Thirty-nine children were treated consecutively with EPO (100 U x kg(-1) s.c. three times a week in the 3 weeks preceding the operation and i.v. on the day of surgery) and two ABDs were made (Group 1). As controls to compare transfusion requirements, 39 consecutive age-matched patients who had undergone open heart surgery during the two preceding years were selected (Group 2). In a mean time of 20 (SD 5) days, 96% of scheduled ABDs were performed and only three mild vasovagal reactions were observed. The mean volume of autologous red blood cells (RBC) collected was 6 (1) ml x kg(-1) and the mean volume of autologous RBC produced as a result of EPO therapy before surgery was 7 (3) ml x kg(-1), corresponding to a 28 (11)% increase in circulating RBC volume. The mean volume of autologous RBC collected was not different from that produced [6 (1) vs 7 (3) ml x kg(-1), P=0.4]. Allogenic blood was administered to three out of 39 children in Group 1 (7.7%) and to 24 out of 39 (61.5%) in Group 2. Treatment with subcutaneous EPO increases the amount of autologous blood that can be collected and minimizes allogenic blood exposure in children undergoing open heart surgery.

Aprotinin Use in Pediatric Cardiac Surgery

Aprotinin is a serine protease inhibitor that inhibits kal likrein and plasmin. Aprotinin's plasmin inhibition accounts for its antifibrinolytic and platelet-sparing effects, which are important factors for its homeostatic efficacy. The kallikrein inhibition occurs at higher plasma levels and is the mecha nism accounting for its anti-inflammatory actions. Aprotinin has relatively large acquisition costs, but these costs are offset by potential reductions in transfusions and intensive care costs. This review summarizes the pediatric literature and develops generalized recommendations for the effica cious use of aprotinin.

Efficacy of aprotinin, epsilon aminocaproic acid, or combination in cyanotic heart disease

BACKGROUND

Aprotinin and epsilon aminocaproic acid are antifibrinolytic agents used to reduce postoperative blood loss after cardiopulmonary bypass. We compared low dose aprotinin with epsilon aminocaproic acid and a combination of the two agents to reduce postoperative blood loss in infants with congenital cyanotic heart disease undergoing corrective surgical procedures.

METHODS

This prospective study was conducted randomly on 300 children. Group I (n = 80) acted as the control and did not receive either of the study drugs. Group II (n = 100) received low dose aprotinin, group III (n = 60) received epsilon aminocaproic acid, and group IV (n = 60) received a combination of the two antifibrinolytic agents.

RESULTS

The control group had the longest time for sternal closure, maximum blood loss at 24 hours, and greatest requirements for packed red blood cells and platelets. Fibrinogen levels were significantly lower, and levels of fibrin breakdown products were significantly higher compared with the groups given either or both of the antifibrinolytics.

CONCLUSIONS

Epsilon aminocaproic acid is as efficacious as low dose aprotinin in reducing postoperative blood loss and packed red blood cell and platelet requirements in children with congenital cyanotic heart disease. The combination of the two was slightly more effective.

Blood transfusion support in pediatric cardiovascular surgery

The majority of children who undergo open-heart surgery with cardiopulmonary bypass (CPB) require perioperative blood transfusion. Blood product requirements are affected by factors such as patient age, underlying cardiac disease, complexity of the surgical procedure, and hemostatic alterations induced by CPB. Transfusion support may include the use of whole blood and/or individual blood components with transfusion practices varying widely based on individual preferences and blood product availability. Approaches to limit allogeneic blood exposure include the use of modified ultrafiltration and smaller bypass circuits, preoperative autologous blood donation and intraoperative blood salvage, and adjunctive antifibrinolytic agents. Potential advantages and disadvantages of the different blood products and pharmacological agents must be considered in managing the pediatric cardiac surgery patient.

Coagulation tests during cardiopulmonary bypass correlate with blood loss in children undergoing cardiac surgery

OBJECTIVES

To examine whether coagulation tests, sampled before and during cardiopulmonary bypass (CPB), are related to blood loss and blood product transfusion requirements, and to determine what test value(s) provide the best sensitivity and specificity for prediction of excessive hemorrhage.

DESIGN

Prospective.

SETTING

University-affiliated, pediatric medical center.

PARTICIPANTS

Four hundred ninety-four children.

INTERVENTIONS

Coagulation tests.

MEASUREMENTS AND MAIN RESULTS

Demographic, coagulation test, blood loss, and transfusion data were noted in consecutive children undergoing cardiac surgery. Laboratory tests included hematocrit (Hct), prothrombin time, partial thromboplastin time (PTT), platelet count, fibrinogen concentration, and thromboelastography. Stepwise linear regression analysis indicated that platelet count during CPB was the variable most significantly associated with intraoperative blood loss (in milliliters per kilogram) and 12-hour chest tube output (in milliliters per kilogram). Other independent variables associated with blood loss were thromboelastography maximum amplitude (MA) during CPB, preoperative PTT, preoperative Hct, and preoperative thromboelastography angle and shear modulus values. Thromboelastography MA during CPB was the only variable associated with total products transfused (in milliliters per kilogram). Of all tests studied, platelet count during CPB (< or = 108,000/microL) provided the maximum sensitivity (83%) and specificity (58%) for prediction of excessive blood loss (receiver operating characteristic analysis). Blood loss was inversely related to patient age; neonates received the most donor units (median, 8 units; range, 6 to 10 units).

CONCLUSIONS

During cardiac surgery, coagulation tests (including thromboelastography) drawn pre-CPB and during CPB are useful to identify children at risk for excessive bleeding. Platelet count during CPB was the variable most significantly associated with blood loss.