Relationship Between Transfusion of Blood Products and the Incidence of Thrombotic Complications in Neonates and Infants Undergoing Cardiac Surgery

A case-control study of bleeding risk in children with 22q11.2 deletion syndrome undergoing cardiac surgery

Previous research suggests that individuals with 22q11.2 deletion syndrome (DS) have an increased risk of bleeding following cardiac surgery. However, current guidelines for management of patients with 22q11.2DS do not provide specific recommendations for perioperative management. This study sought to identify specific risk factors for bleeding in this patient population. Examine the factors determining bleeding and transfusion requirements in patients with 22q11.2DS undergoing cardiac surgery. This was a single center review of patients who underwent cardiac surgery at the Children's Hospital of Philadelphia from 2000 to 2016. Data was extracted from the medical record. Frequency of bleeding events, laboratory values, and transfusion requirements were compared. We included 226 patients with 22q11.2DS and 506 controls. Bleeding events were identified in 13 patients with 22q11.2DS (5.8%) and 27 controls (5.3%). Platelet counts were lower among patients with 22q11.2DS than in control patients, but not statistically different comparing bleeding to not bleeding. Patients with 22q11.2DS received more transfusions (regardless of bleeding status). However, multivariate analysis showed only procedure type was associated with increased risk of bleeding (p = .012). The overall risk of bleeding when undergoing cardiac surgery is not different in patients with 22q11.2DS compared to non-deleted patients. Though platelet counts were lower in patients with 22q11.2DS, only procedure type was significantly associated with an increased risk of bleeding.

Effect of In Vivo Administration of Fibrinogen Concentrate Versus Cryoprecipitate on Ex Vivo Clot Degradation in Neonates Undergoing Cardiac Surgery

BACKGROUND

Neonates undergoing cardiac surgery require fibrinogen replacement to restore hemostasis after cardiopulmonary bypass (CPB). Cryoprecipitate is often the first-line treatment, but recent studies demonstrate that fibrinogen concentrate (RiaSTAP; CSL Behring) may be acceptable in this population. This investigator-initiated, randomized trial compares cryoprecipitate to fibrinogen concentrate in neonates undergoing cardiac surgery (ClinicalTrials.gov NCT03932240). The primary end point was the percent change in ex vivo clot degradation from baseline at 24 hours after surgery between groups. Secondary outcomes included intraoperative blood transfusions, coagulation factor levels, and adverse events.

METHODS

Neonates were randomized to receive cryoprecipitate (control group) or fibrinogen concentrate (study group) as part of a post-CPB transfusion algorithm. Blood samples were drawn at 4 time points: presurgery (T1), after treatment (T2), arrival to the intensive care unit (ICU) (T3), and 24 hours postsurgery (T4). Using the mixed-effect models, we analyzed the percent change in ex vivo clot degradation from a patient's presurgery baseline at each time point. Intraoperative blood product transfusions, coagulation factor levels, perioperative laboratory values, and adverse events were collected.

RESULTS

Thirty-six neonates were enrolled (intent to treat [ITT]). Thirteen patients in the control group and seventeen patients in the study group completed the study per protocol (PP). After normalizing to the patient's own baseline (T1), no significant differences were observed in clot degradation at T2 or T3. At T4, patients in the study group had greater degradation when compared to those in the control group (826.5%, 95% confidence interval [CI], 291.1-1361.9 vs -545.9%, 95% CI, -1081.3 to -10.4; P < .001). Study group patients received significantly less median post-CPB transfusions than control group patients (ITT, 27.2 mL/kg [19.0-36.9] vs 41.6 [29.2-52.4]; P = .043; PP 26.7 mL/kg [18.8-32.2] vs 41.2 mL/kg [29.0-51.4]; P < .001). No differences were observed in bleeding or thrombotic events.

CONCLUSIONS

Neonates who received fibrinogen concentrate, as compared to cryoprecipitate, have similar perioperative ex vivo clot degradation with faster degradation at 24 hours postsurgery, less post-CPB blood transfusions, and no increased bleeding or thrombotic complications. Our findings suggest that fibrinogen concentrate adequately restores hemostasis and reduces transfusions in neonates after CPB without increased bleeding or thrombosis risk.

Perioperative Hyper-coagulation and Thrombosis: Cost Analysis After Congenital Heart Surgery

Thrombosis, a major adverse event of congenital heart surgery, has been associated with poor outcomes. We hypothesized that in CHD patients undergoing cardiac surgery, increased perioperative use of pro-coagulant products may be associated with postoperative thrombosis in the setting of hyperfibrinogenemia, leading to greater hospital and blood product costs. Single-center retrospective study. Data from Boston Children's Hospital's electronic health record database was used in this study. All patients undergoing congenital heart surgery between 2015 and 2018 with postoperative fibrinogen levels above 400 mg/dl were reviewed. Of 334 patients with high plasma fibrinogen levels, 28 (8.4%) developed postoperative thrombosis (median age: one year, 59% male). In our cohort, 25 (7%) demonstrated evidence of baseline hypercoagulability by one or more panel test results. Thrombosis was associated with greater hospital and blood product costs, longer ventilation times, and longer hospital and ICU length of stays. Preoperative hypercoagulable state (odds ratio: 2.58, 95% CI [1.07, 9.99], p = 0.002), postoperative red blood cell transfusion (odds ratio: 1.007, 95% CI [1.000, 1.015], p = 0.04), and single ventricle physiology (univariate odds ratio: 2.94, 95% CI [1.09, 7.89], p = 0.03) were predictors of postoperative thrombosis. Preoperative hypercoagulable state and intraoperative platelet transfusion were predictors of hospital cost. Thrombosis was associated with worse in-hospital outcomes and higher costs. Preoperative hypercoagulable state and postoperative red blood cell transfusion were significant predictors of thrombosis. Risk prediction models that can guide thrombosis prevention are needed to improve outcomes of patients undergoing congenital heart surgery.

Approach to red blood cell transfusions in post-operative congenital heart disease surgery patients: when to stop?

BACKGROUND

The best transfusion approach for CHD surgery is controversial. Studies suggest two strategies: liberal (haemoglobin ≤ 9.5 g/dL) and restrictive (waiting for transfusion until haemoglobin ≤ 7.0 g/dL if the patient is stable). Here we compare liberal and restrictive transfusion in post-operative CHD patients in a cardiac intensive care unit.

METHODS

Retrospective analysis was conducted on CHD patients who received liberal transfusion (2019-2021, n=53) and restrictive transfusion (2021-2022, n=43).

RESULTS

The two groups were similar in terms of age, gender, Paediatric Risk of Mortality-3 score, Paediatric Logistic Organ Dysfunction-2 score, Risk Adjustment for Congenital Heart Surgery-1 score, cardiopulmonary bypass time, vasoactive inotropic score, total fluid balance, mechanical ventilation duration, length of cardiac intensive care unit stay, and mortality. The liberal transfusion group had a higher pre-operative haemoglobin level than the restrictive group (p < 0.05), with no differences in pre-operative anaemia. Regarding the minimum and maximum post-operative haemoglobin levels during a cardiac intensive care unit stay, the liberal group had higher haemoglobin levels in both cases (p<0.01 and p=0.019, respectively). The number of red blood cell transfusions received by the liberal group was higher than that of the restrictive group (p < 0.001). There were no differences between the two groups regarding lactate levels at the time of and after red blood cell transfusion. The incidence of bleeding, re-operation, acute kidney injury, dialysis, sepsis, and systemic inflammatory response syndrome was similar.

CONCLUSIONS

Restrictive transfusion may be preferable over liberal transfusion. Achieving similar outcomes with restrictive transfusions may provide promising evidence for future studies.

A Review of Biventricular Repair for the Congenital Cardiac Anesthesiologist

The management of children with a borderline ventricle has been debated for many years. The pursuit of a biventricular repair in these children aims to avoid the long-term sequelae of single ventricle palliation. There is a lack of anesthesia literature relating to the care of this complex heterogenous patient population. Anesthesiologists caring for these patients should have an understanding on the many different forms of physiology and the impact on provision of anesthesia and hemodynamic parameters, the goals of biventricular staging and completion as well as the pre-operative, intra-operative, and post-operative considerations relating to this high-risk group of patients.

Activated 4-Factor Prothrombin Complex Concentrate as a Hemostatic Adjunct for Neonatal Cardiac Surgery: A Propensity Score-Matched Cohort Study

BACKGROUND

Prothrombin complex concentrates are an emerging "off-label" therapy to augment hemostasis after cardiopulmonary bypass (CPB), but data supporting their use for neonatal cardiac surgery are limited.

METHODS

We retrospectively reviewed neonates undergoing open heart surgery with first-time sternotomy between May 2014 and December 2018 from a hospital electronic health record database. Neonates who received activated 4-factor prothrombin complex concentrate (a4FPCC) after CPB were propensity score matched (PSM) to neonates who did not receive a4FPCC (control group). The primary efficacy outcome was total volume (mL/kg) of blood products transfused after CPB, including the first 24 hours on the cardiovascular intensive care unit (CVICU). The primary safety outcome was the incidence of 7- and 30-day postoperative thromboembolism. Secondary outcomes included 24 hours postoperative chest tube output, time to extubation, duration of CVICU stay, duration of hospital stay, 30-day mortality, and incidence of acute kidney injury on postoperative day 3. We used linear regression modeling on PSM data for the primary efficacy outcome. For the primary safety outcome, we tested for differences using McNemar test on PSM data. For secondary outcomes, we used linear regression, Fisher exact test, or survival analyses as appropriate, with false discovery rate-adjusted P values.

RESULTS

A total of 165 neonates were included in the final data analysis: 86 in the control group and 79 in the a4FPCC group. After PSM, there were 43 patients in the control group and 43 in the a4FPCC group. We found a statistically significant difference in mean total blood products transfused for the a4FPCC group (47.5 mL/kg) compared with the control group (63.7 mL/kg) for PSM patients (adjusted difference, 15.3; 95% CI, 29.4-1.3; P = .032). We did not find a statistically significant difference in 7- or 30-day thromboembolic rate, postoperative chest tube output, time to extubation, incidence of postoperative acute kidney injury (AKI), or 30-day mortality between the groups. The a4FPCC group had a significantly longer length of intensive care unit stay (32.9 vs 13.3 days; adjusted P = .049) and hospital stay (44.6 vs 24.1 days; adjusted P = .049) compared with the control group.

CONCLUSIONS

We found that the use of a4FPCC as a hemostatic adjunct for post-CPB bleeding in neonatal cardiac surgery was associated with a decrease in mean total blood products transfused after CPB without an increased rate of 7- or 30-day postoperative thromboembolism. Our findings suggest that a4FPCCs can be considered as part of a hemostasis pathway for refractory bleeding in neonatal cardiac surgery.

Intraoperative blood product transfusion in pediatric cardiac surgery patients: A retrospective review of adverse outcomes

BACKGROUND

Resuscitation with blood products is often required for pediatric cardiac surgery patients following cardiopulmonary bypass. However, data suggest that blood product transfusion is an independent predictor of adverse outcomes. Most studies have specifically found detrimental effects of overall transfusion of red blood cells in particular, but few have analyzed outcomes by the other specific blood product components.

AIMS

The objective of this study is to analyze adverse outcomes associated with intraoperative transfusion of specific blood product components.

METHODS

A retrospective review was performed on 643 pediatric patients who underwent cardiac surgery requiring cardiopulmonary bypass to evaluate the risk of selected adverse outcomes associated with intraoperative blood product transfusion. Adverse outcomes included thrombotic complications, stroke, acute kidney injury, prolonged mechanical ventilation, and death. Univariate logistic and linear regression analyses were performed to explore the association between various blood products and the occurrence of postoperative complications. Multiple logistic and linear regression analyses were performed adjusting for age, cyanotic status, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Score (STAT score), and cardiopulmonary bypass time.

RESULTS

Unadjusted analysis using univariate logistic and linear regressions showed statistically significant associations of almost all blood components (per 10 mL/kg dose increments) with multiple postoperative complications, including mortality, thrombotic complications, stroke, and days of mechanical ventilation. After adjusting for patient age, cyanotic status, STAT score, and cardiopulmonary bypass time, multivariable logistic and linear regression analyses revealed no association between transfusion of blood products with acute kidney injury and stroke. Administration of red blood cells was the only category significantly correlated with increased days of mechanical ventilation (0.5 days increase in mechanical ventilation per 10 mL/kg transfusion of red blood cells). The only blood product to show complete lack of a statistically significant association with any of the studied outcomes was cryoprecipitate.

CONCLUSIONS

Transfusion of blood products following cardiopulmonary bypass is associated with postoperative adverse outcomes. Future studies aimed at strategies to reduce intraoperative bleeding and decrease the amount of blood products administered are warranted.

Chylothorax in newborns after cardiac surgery: a rare complication?

The aim of this study was to analyze patients diagnosed with chylothorax after congenital heart disease surgery among a cohort of neonatal patients, comparing the evolution, complications, and prognosis after surgery of patients who were and were not diagnosed with chylothorax, and to analyze possible risk factors that may predict the appearance of chylothorax in this population. Retrospective and observational study included all neonates (less than 30 days since birth) who underwent congenital heart disease surgery in a level III neonatal intensive care department. We included infants born between January 2014 and December 2019. We excluded those infants who were born before 34 weeks of gestational age or whose birth weight was less than 1800 g. We also excluded catheter lab procedures and patent ductus arteriosus closure surgeries. Included patients were divided into two groups depending on whether they were diagnosed with chylothorax or not after surgery, and both groups were compared in terms of perinatal-obstetrical information, surgical data, and NICU course after surgery. We included 149 neonates with congenital heart disease surgery. Thirty-one patients (20.8%) developed chylothorax, and in ten patients (32.3%), it was considered large volume chylothorax. Regarding the evolution of these patients, 22 infants responded to general dietetic measures, a catheter procedure was performed in 9, and 5 of them finally required pleurodesis. Cardiopulmonary bypass, median sternotomy, and delayed sternal closure were the surgical variables associated with higher risks of chylothorax. Patients with chylothorax had a longer duration of inotropic support and mechanical ventilation and took longer to reach full enteral feeds. As complications, they had higher rates of cholestasis, catheter-related sepsis, and venous thrombosis. Although there were no differences in neonatal mortality, patients with chylothorax had a higher rate of mortality after the neonatal period. In a multiple linear regression model, thrombosis and cardiopulmonary bypass multiplied by 10.0 and 5.1, respectively, the risk of chylothorax and have an umbilical vein catheter decreases risk.

CONCLUSION

We have found a high incidence of chylothorax after neonatal cardiac surgery, which prolongs the average stay and causes significant morbidity and mortality. We suggested that chylothorax could be an underestimated complication of congenital heart disease surgery during the neonatal period.

WHAT IS KNOWN

• Acquired chylothorax in the neonatal period usually appears as a complication of congenital heart disease surgery, being the incidence quite variable among the different patient series (2.5-16.8%). The appearance of chylothorax as a complication of a cardiac surgery increases both mortality and morbidity in these patients, which makes it a quality improvement target in the postsurgical management of this population.

WHAT IS NEW

•Most of the published studies include pediatric patients of all ages, from newborns to teenagers, and there is a lack of studies focusing on neonatal populations. The main strength of our study is that it reports, to the best of our knowledge, one of the largest series of neonatal patients receiving surgery for congenital heart disease in the first 30 days after birth. We have found a high incidence of chylothorax after cardiac surgery during the neonatal period compared to other studies. We suggested that chylothorax could be an underestimated complication of congenital heart disease surgery during this period of life.

Acute Cardiac Care for Neonatal Heart Disease

This manuscript is one component of a larger series of articles produced by the Neonatal Cardiac Care Collaborative that are published in this supplement of Pediatrics. In this review article, we summarize the contemporary physiologic principles, evaluation, and management of acute care issues for neonates with complex congenital heart disease. A multidisciplinary team of authors was created by the Collaborative's Executive Committee. The authors developed a detailed outline of the manuscript, and small teams of authors were assigned to draft specific sections. The authors reviewed the literature, with a focus on original manuscripts published in the last decade, and drafted preliminary content and recommendations. All authors subsequently reviewed and edited the entire manuscript until a consensus was achieved. Topics addressed include cardiopulmonary interactions, the pathophysiology of and strategies to minimize the development of ventilator-induced low cardiac output syndrome, common postoperative physiologies, perioperative bleeding and coagulation, and common postoperative complications.

Association of red blood cell transfusion volume with postoperative complications and mortality in neonatal surgery

INTRODUCTION

Red blood cell transfusion (RBCT) is commonly administered in neonatal surgical care in the absence of clear clinical indications such as active bleeding or anemia. We hypothesized that higher RBCT volumes are associated with worse postoperative outcomes.

METHODS

Neonates within the National Surgical Quality Improvement Program-Pediatric database who underwent inpatient surgery (2012-2016) were stratified by weight-based RBCT volume: <20cc/kg, 20-40cc/kg, and >40cc/kg. Postoperative complications were categorized as wound, systemic infection, central nervous system (CNS), renal, pulmonary, and cardiovascular. Multivariable logistic regression and cubic spline analysis were used to evaluate the association between RBCT volume, postoperative complications, and 30-day mortality. Sensitivity analysis was conducted by performing propensity score matching.

RESULTS

Among 9,877 neonates, 1,024 (10%) received RBCTs. Of those who received RBCT, 53% received <20cc/kg, 27% received 20-40cc/kg, and 20% received >40cc/kg. Relative to neonates who were not transfused, RBCT volume was associated with a dose-dependent increase in renal complications, CNS complications, cardiovascular complications, and 30-day mortality. With cubic spline analysis, a lone inflection point for 30-day mortality was identified at a RBCT volume of 30 - 35 cc/kg. After propensity score matching, the dose-dependent relationship was still present for 30-day mortality.

CONCLUSION

Total RBCT volume is associated with worse postoperative outcomes in neonates with a significant increase in 30-day mortality at a RBCT volume of 30 - 35 cc/kg. Future prospective studies are needed to better understand the association between large RBCT volumes and poor outcomes after neonatal surgery.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Questions about COVID-19 associated coagulopathy: possible answers from the viscoelastic tests

Abnormal coagulation parameters are often observed in patients with coronavirus disease 2019 (COVID-19) and the severity of derangement has been associated with a poor prognosis. The COVID-19 associated coagulopathy (CAC) displays unique features that include a high risk of developing thromboembolic complications. Viscoelastic tests (VETs), such as thromboelastometry (ROTEM), thromboelastography (TEG) and Quantra Hemostasis Analyzer (Quantra), provide "dynamic" data on clot formation and dissolution; they are used in different critical care settings, both in hemorrhagic and in thrombotic conditions. In patients with severe COVID-19 infection VETs can supply to clinicians more information about the CAC, identifying the presence of hypercoagulable and hypofibrinolysis states. In the last year, many studies have proposed to explain the underlying characteristics of CAC; however, there remain many unanswered questions. We tried to address some of the important queries about CAC through VETs analysis.

Plasma and Platelet Transfusions Strategies in Neonates and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass or Neonates and Children Supported by Extracorporeal Membrane Oxygenation: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present the recommendations and consensus statements with supporting literature for plasma and platelet transfusions in critically ill neonates and children undergoing cardiac surgery with cardiopulmonary bypass or supported by extracorporeal membrane oxygenation from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of nine experts developed evidence-based and, when evidence was insufficient, expert-based statements for plasma and platelet transfusions in critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed one good practice statement, two recommendations, and three expert consensus statements.

CONCLUSIONS

Whereas viscoelastic testing and transfusion algorithms may be considered, in general, evidence informing indications for plasma and platelet transfusions in neonatal and pediatric patients undergoing cardiac surgery with cardiopulmonary bypass or those requiring extracorporeal membrane oxygenation support is lacking.

Viscoelastic testing in pediatric patients

A tailored transfusion algorithm based on viscoelastic testing in the perioperative period or in trauma patients is recommended by guidelines for bleeding management. Bleeding management strategies in neonates and children are mostly extrapolated from the adult experience, as published evidence in the youngest age group is scarce. This manuscript is intended to give a structured overview of what has been published on the use of viscoelastic testing to guide bleeding management in neonates and children. Several devices that use either the traditional viscoelastic method or resonance viscoelastography technology are on the market. Reference ranges for children have been evaluated in only some of them. As most of the hemostasis maturation processes can be observed during the first year of life, adult reference ranges for viscoelastic testing could be applied over the age of 1 year. The majority of the published trials in children are based on retrospective analyses describing the correlation between viscoelastic testing and standard laboratory testing or focusing on the prediction of bleeding. Clinically more relevant studies in pediatric patients undergoing cardiac surgery have demonstrated that the implementation of a transfusion algorithm based on viscoelastic testing has significantly reduced transfusion requirements and that this approach has enabled a rapid detection of coagulation disorders in the presence of excessive bleeding. Although further studies are urgently needed, experts have reviewed the use of a transfusion algorithm based on viscoelastic testing in children as a feasible approach, as it has been shown to improve bleeding management and rationalize blood product transfusion.

Neonatal coagulopathies: A review of established and emerging treatments

Despite the relative frequency of both bleeding and clotting disorders among patients treated in the neonatal intensive care unit, few clear guidelines exist for treatment of neonatal coagulopathies. The study and treatment of neonatal coagulopathies are complicated by the distinct hemostatic balance and clotting components present during this developmental stage as well as the relative scarcity of studies specific to this age group. This mini-review examines the current understanding of neonatal hemostatic balance and treatment of neonatal coagulopathies, with particular emphasis on emerging treatment methods and areas in need of further investigative efforts.

Thromboelastography During Rewarming for Management of Pediatric Cardiac Surgery Patients

BACKGROUND

Thromboelastography (TEG) predicts bleeding in pediatric patients undergoing cardiac surgery. We hypothesize that TEG parameters at rewarming correlate with post-protamine values and that rewarming TEG is associated with surrogate endpoints for postoperative bleeding in pediatric patients undergoing complex cardiac surgery.

METHODS

In a retrospective study of pediatric (≤18yrs) patients (N=703) undergoing complex cardiac surgery procedures, TEG obtained during rewarming and following protamine administration were compared using linear regression. A composite endpoint of extended blood product transfusion or surgical re-exploration for bleeding was utilized as a surrogate for post-operative bleeding.

RESULTS

By multivariable analysis, longer cardiopulmonary bypass time and lower TEG maximal amplitude (MA) during rewarming were independently associated with risk of composite endpoint in the operating room or intensive care unit (p<0.05). Among patients with MA<45mm during rewarming, those who received platelet transfusion compared to those who did not in the operating room were less likely to reach composite endpoint within the subsequent 24 hours (8%vs.32% respectively; p<0.01). Good correlation was observed between TEG parameters at rewarming vs. after protamine administration (Pearson r≥0.7). The relationship between platelet transfusion volume (ml/kg) and percent change in MA was determined using linear regression and a platelet transfusion calculator was generated.

CONCLUSIONS

Lower MA during rewarming is associated with increased risk of perioperative bleeding. In patients with rewarming MA<45mm, intraoperative platelet transfusion may reduce the risk of subsequent bleeding. Individualized platelet transfusion therapy based on rewarming TEG may reduce the risk of bleeding while minimizing unnecessary platelet transfusion.

Stratification of Bleeding Risk Using Thromboelastography in Children on Extracorporeal Membrane Oxygenation Support

OBJECTIVES

Patients undergoing extracorporeal membrane oxygenation are at high risk for bleeding and thrombotic complications. Current laboratory methods for assessing the coagulation system may be imprecise and complicate clinical decision-making. We hypothesize that thromboelastography may be more strongly associated with bleeding events than traditional methods and can aid extracorporeal membrane oxygenation coagulation management.

DESIGN

In a retrospective study, 40 patients with congenital heart disease requiring extracorporeal membrane oxygenation support yielded a total of 159 patient days of data for thromboelastography analysis.

SETTING

Pediatric cardiac ICU at a single institution.

SUBJECTS

Pediatric patients (≤ 18 yr) with congenital heart disease requiring extracorporeal membrane oxygenation support.

INTERVENTIONS

None.

METHODS

Thromboelastography was performed on whole blood samples collected 6-12 hours following extracorporeal membrane oxygenation initiation and daily for the duration of extracorporeal membrane oxygenation. Bleeding during each 24-hour period was defined as need for re-exploration or need for blood transfusion. Associations between thromboelastography variables and bleeding over each 24-hour period (bleeding vs nonbleeding days) were assessed using mixed effects logistic regression and classification and regression tree analysis.

MEASUREMENTS AND MAIN RESULTS

Bleeding occurred in 25 patients (63%), contributing 87 bleeding days (55% extracorporeal membrane oxygenation days) for analysis. The probability of bleeding within the 24-hour period was not associated with activated partial thromboplastin time (p = 0.6) or anti-Xa levels (p = 0.3) on that day. The strongest correlate of bleeding was a maximum amplitude less than 55.4 mm on thromboelastography (odds ratio, 3.28; 95% CI, 1.63-6.60; p < 0.001). Bleeding occurred on 73% versus 35% of extracorporeal membrane oxygenation days for maximum amplitude less than 55.4 mm versus greater than or equal to 55.4 mm, respectively. Bleeding occurred on all days when a combination of maximum amplitude less than 55.4 mm and a reaction time greater than 12.9 minutes was present. The lowest risk of bleeding (28% of patient days) was associated with maximum amplitude greater than or equal to 55.4 mm and plasma fibrinogen greater than 345 mg/dL.

CONCLUSIONS

Thromboelastography-derived variables maximum amplitude and reaction time, along with plasma fibrinogen levels, can help predict bleeding events in children on extracorporeal membrane oxygenation support. Research based on larger patient samples is needed to confirm the specific thresholds identified for bleeding risk stratification for extracorporeal membrane oxygenation anticoagulation management.

Transfusion Outcomes in Patients Undergoing Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals

BACKGROUND

Surgical repair of tetralogy of Fallot and major aortopulmonary collaterals (TOF/MAPCAs) involves unifocalization of MAPCAs and reconstruction of the pulmonary arterial circulation. Surgical and cardiopulmonary bypass (CPB) times are long and suture lines are extensive. Maintaining patency of the newly anastomosed vessels while achieving hemostasis is important, and assessment of transfusion practices is critical to successful outcomes.

METHODS

Clinical, surgical, and transfusion data in patients with TOF/MAPCAs repaired at our institution (2013-2018) were reviewed. Types and volumes of blood products used in the perioperative period, in addition to the use of antifibrinolytics and/or procoagulants (factor VIII inhibitor bypassing activity [FEIBA]; anti-inhibitor coagulant complex), were assessed. Outcome measures included days on mechanical ventilation (DOMV), postoperative intensive care unit and hospital length of stay (LoS), and incidence of thrombosis.

RESULTS

Perioperative transfusion data from 279 patients were analyzed. Surgical (879 ± 175 minutes vs 684 ± 257 minutes) and CPB times (376 ± 124 minutes vs 234 ± 122 minutes) were longer in patients who received FEIBA than those who did not. Although the indexed volume of packed red blood cells (128.4 ± 82.2 mL/kg) and fresh frozen plasma (64.2 ± 41.1 mL/kg) was similar in patients who did and did not receive FEIBA, the amounts of cryoprecipitate (5.5 ± 5.2 mL/kg vs 5.8 ± 4.8 mL/kg) and platelets (19.5 ± 20.7 mL/kg vs 20.8 ± 13 mL/kg) transfused were more in those who did receive FEIBA.

CONCLUSION

Perioperative transfusion is an important component in the overall surgical and anesthetic management of patients with TOF/MAPCAs. The intraoperative use of FEIBA was not associated with a decrease in the amount of blood products transfused, DOMV, or LoS or with an increase in thrombotic complications.

COVID-19-Associated Coagulopathy and Inflammatory Response: What Do We Know Already and What Are the Knowledge Gaps?

Patients with coronavirus disease 2019 (COVID-19) frequently experience a coagulopathy associated with a high incidence of thrombotic events leading to poor outcomes. Here, biomarkers of coagulation (such as D-dimer, fibrinogen, platelet count), inflammation (such as interleukin-6), and immunity (such as lymphocyte count) as well as clinical scoring systems (such as sequential organ failure assessment [SOFA], International Society on Thrombosis and Hemostasis disseminated intravascular coagulation [ISTH DIC], and sepsis-induced coagulopathy [SIC] score) can be helpful in predicting clinical course, need for hospital resources (such as intensive care unit [ICU] beds, intubation and ventilator therapy, and extracorporeal membrane oxygenation [ECMO]) and patient's outcome in patients with COVID-19. However, therapeutic options are actually limited to unspecific supportive therapy. Whether viscoelastic testing can provide additional value in predicting clinical course, need for hospital resources and patient's outcome or in guiding anticoagulation in COVID-19-associated coagulopathy is still incompletely understood and currently under investigation (eg, in the rotational thromboelastometry analysis and standard coagulation tests in hospitalized patients with COVID-19 [ROHOCO] study). This article summarizes what we know already about COVID-19-associated coagulopathy and-perhaps even more importantly-characterizes important knowledge gaps.

Use of Coagulation Point-of-Care Tests in the Management of Anticoagulation and Bleeding in Pediatric Cardiac Surgery: A Systematic Review

Bleeding and coagulation management are essential aspects in the management of neonates and children undergoing cardiac surgery. The use of point-of-care tests (POCTs) in a pediatric setting is not as widely used as in the adult setting. This systematic review aims to summarize the evidence showed by the literature regarding the use of POCTs in children undergoing cardiac surgery. We included all studies examining the pediatric population (<18 years old) undergoing cardiac surgery in which the coagulation profile was assessed with POCTs. Three electronic databases (PubMed, Embase, and the Cochrane Controlled Clinical Trials register) were searched. Tests involved were heparin effect tests, viscoelastic tests, and platelet function tests. Due to the wide heterogeneity of the patients and tests studied, a formal meta-analysis was impossible, and the results are therefore presented through a systematic review. Eighty articles were found, of which 47 are presented in this review. At present, literature data are too weak to define POCTs as a "gold standard" for the treatment of perioperative bleeding in pediatric cardiac surgery. Nevertheless, introduction of POCTs into postoperative algorithms has shown to improve bleeding management, patient outcome, and cost efficiency.

Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes

Background Packed red blood cell transfusion may improve oxygen content in single-ventricle neonates, but its effect on clinical outcomes after Stage 1 palliation is unknown. Methods and Results Retrospective multicenter analysis of packed red blood cell transfusion exposures in neonates after Stage 1 palliation, excluding those with intraoperative mortality or need for extracorporeal membrane oxygenation. Transfusion practice variability was assessed, and multivariable regression used to identify transfusion risk factors. After propensity score adjustment for severity of illness, clinical outcomes were compared between transfused and nontransfused subjects. Of 396 subjects, 323 (82%) received 930 postoperative red blood cell transfusions. Packed red blood cell volume (median 9-42 mL/kg [P<0.0001]), donor exposures (1-2 [P<0.0001]), transfusion number (1-3 [P<0.0001]), and pretransfusion hemoglobin (12.1-13 g/dL, P=0.0049) varied between sites. Cyanosis (P=0.02), chest tube output (P=0.0003), and delayed sternal closure (P=0.0033) increased transfusion risk. Transfusion was associated with prolonged mechanical ventilation (6 [interquartile range 4, 12] versus 3 [1, 5] days, P=0.02) and intensive care unit stay (19 [12, 33] versus 9 [6, 19] days, P=0.016). When stratified by number of transfusions (0, 1, or >1), duration of mechanical ventilation (3 [1, 5] versus 4 [3, 6] versus 9 [5, 16] days [P<0.0001]) and intensive care unit stay (9 [6, 19] versus 13 [8, 25] versus 21 [13, 38] days [P<0.0001]) increased for those transfused more than once. Most subjects who died were transfused, though the association with mortality was not significant. Conclusions Packed red blood cell transfusion after Stage 1 palliation is common, and transfusion practice is variable. Transfusion is a significant predictor of longer intensive care unit stay and mechanical ventilation. Further studies to define evidence-based transfusion thresholds are warranted.

Pediatric non-red cell blood product transfusion practices: what's the evidence to guide transfusion of the 'yellow' blood products?

PURPOSE OF REVIEW

Research studies pertaining to the management of pediatric non-red cell blood product transfusion is limited. Clinical practices vary within disciplines and regions. Anesthesiologists need evidence-based guidelines to make appropriate and safe decisions regarding transfusion of the 'yellow' blood products for pediatric patients.

RECENT FINDINGS

This review outlines clinical indications for transfusion of fresh frozen plasma, cryoprecipitate, platelets, and fibrinogen concentrate in pediatrics. Recent studies of non-red blood cell transfusions in critical, but stable situations are highlighted. Recommendations to guide transfusion of the 'yellow' blood products in operative and non-operative settings are summarized. Special attention is drawn to guidelines in massive hemorrhage and trauma situations.

SUMMARY

Evidence-based guidelines and expert consensus recommendations exist to guide the transfusion of pediatric non-red blood products and should be followed when transfusing the 'yellow' blood components. As high-quality studies in neonates, infants and children are limited, future research should broaden our knowledge in this direction with the goal to use restrictive strategies to improve patient outcomes.

A Retrospective Analysis of the Use of 3-Factor Prothrombin Complex Concentrates for Refractory Bleeding After Cardiopulmonary Bypass in Children Undergoing Heart Surgery: A Matched Case-Control Study

The 3-factor prothrombin complex concentrate (3FPCC) may be used off-label to treat refractory bleeding during cardiac surgery in children. This retrospective study examined the rate of clinical complications following the use of 3FPCC. Patients treated with 3FPCC were matched to controls for age, gender, prematurity, weight, cardiopulmonary bypass times, and cross-clamp times. Fifty-nine cases were individually matched to 59 controls based on propensity scores. 3FPCC was not associated with an increased risk of thromboembolic events, mortality, or need for postoperative extracorporeal membrane oxygenator support. These results suggest the safety of 3FPCC when used for refractory bleeding after cardiopulmonary bypass in children undergoing congenital heart surgery.

Transfusing Platelets During Bypass Rewarming in Neonates Improves Postoperative Outcomes: A Randomized Controlled Trial

Background:

In neonates, transfusion of platelets after hemodilution from cardiopulmonary bypass (CPB) has been standard. We hypothesize that platelet administration during the rewarming phase before termination of CPB would reduce coagulopathy, enhance hemostasis, reduce transfusion, and improve postoperative outcomes after neonatal cardiac surgery.

Methods:

A prospective, randomized trial was performed in 46 neonates. Controls received platelets only at the end of bypass with other blood products to assist in hemostasis. The treatment group received 10 mL/kg of platelets during the rewarming phase of bypass after cross-clamp release. After protamine, transfusion and perioperative management protocols were identical and constant among groups.

Results:

Two neonates in each group were excluded secondary to postoperative need for extracorporeal support. Controls (n = 21) and treatment patients (n = 21) were similar in age, weight, case complexity, associated syndromes, single ventricle status, and CPB times. Compared to controls, the treatment group required 40% less postbypass blood products (58 ± 29 vs 103 ± 80 mL/kg, P = .04), and case completion time after protamine administration was 28 minutes faster ( P = .016). The treatment group required fewer postoperative mediastinal explorations for bleeding ( P = .045) and had a lower fluid balance ( P = .04). The treatment group had shorter mechanical ventilation ( P = .016) and length of intensive care unit times ( P = .033). There were no 30-day mortalities in either group.

Conclusion:

Platelet transfusion during the rewarming phase of neonatal cardiac surgery was associated with reduced bleeding and improved postoperative outcomes, compared to platelets given after coming off bypass. Further studies are necessary to understand mechanisms and benefits of this strategy.

The role of evidence-based algorithms for rotational thromboelastometry-guided bleeding management

Rotational thromboelastometry (ROTEM) is a point-of-care viscoelastic method and enables to assess viscoelastic profiles of whole blood in various clinical settings. ROTEM-guided bleeding management has become an essential part of patient blood management (PBM) which is an important concept in improving patient safety. Here, ROTEM testing and hemostatic interventions should be linked by evidence-based, setting-specific algorithms adapted to the specific patient population of the hospitals and the local availability of hemostatic interventions. Accordingly, ROTEM-guided algorithms implement the concept of personalized or precision medicine in perioperative bleeding management (‘theranostic’ approach). ROTEM-guided PBM has been shown to be effective in reducing bleeding, transfusion requirements, complication rates, and health care costs. Accordingly, several randomized-controlled trials, meta-analyses, and health technology assessments provided evidence that using ROTEM-guided algorithms in bleeding patients resulted in improved patient’s safety and outcomes including perioperative morbidity and mortality. However, the implementation of ROTEM in the PBM concept requires adequate technical and interpretation training, education and logistics, as well as interdisciplinary communication and collaboration.

Analysis of the structural and mechanical effects of procoagulant agents on neonatal fibrin networks following cardiopulmonary bypass

Essentials The standard of care (SOC) for treating neonatal bleeding is transfusion of adult blood products. We compared neonatal clots formed with cryoprecipitate (SOC) to two procoagulant therapies. The current SOC resulted in clots with increased stiffness and decreased fibrinolytic properties. Procoagulant therapies may be a viable alternative to SOC treatment for neonatal bleeding. SUMMARY: Background Bleeding is a serious complication of neonates undergoing cardiopulmonary bypass (CPB) and associated with substantial morbidity and mortality. Bleeding is addressed through the transfusion of adult blood products, including platelets and cryoprecipitate. However, significant differences exist between neonatal and adult clotting components, specifically fibrinogen. Our recent ex vivo studies have shown that neonatal fibrinogen does not fully integrate with adult fibrinogen, leading to decreased susceptibility to fibrinolysis. These differences may contribute to ineffective clot formation and/or an increased risk of thrombosis. A need exists to identify more effective and safer methods to promote clotting in neonates. Objectives Procoagulant agents, such as prothrombin complex concentrates (PCCs) and recombinant activated factor VII (rFVIIa), are being used off-label to treat excessive bleeding in neonates after CPB. Because these agents stimulate endogenous fibrin formation, we hypothesize that their addition to post-CPB neonatal plasma will better recapitulate native clot properties than cryoprecipitate. Methods We analyze the structural, mechanical and degradation properties of fibrin matrices formed by neonatal plasma collected after CPB in the presence of an activated four-factor (F) PCC (FEIBA), rFVIIa, or cryoprecipitate using confocal microscopy, atomic force microscopy and a fluidics-based degradation assay. Results The ex vivo addition of FEIBA and rFVIIa to post-CPB neonatal plasma resulted in enhanced clot networks with differences in fibrin alignment, mechanics and degradation properties. Conclusions Our results suggest that these procoagulant agents could be used as an alternative to the transfusion of adult fibrinogen for the treatment of bleeding after CPB in neonates.

Recent innovations in perfusion and cardiopulmonary bypass for neonatal and infant cardiac surgery

The development and refinement of cardiopulmonary bypass (CPB) has made the repair of complex congenital heart defects possible in neonates and infants. In the past, the primary goal for these procedures was patient survival. Now that substantial survival rates have been achieved for even the most complex of repairs in these patients, focus has been given to the reduction of morbidity. Although a necessity for these complex neonatal and infant heart defect repairs, CPB can also be an important source of perioperative complications. Recent innovations have been developed to mitigate these risks and is the topic of this review. Specifically, we will discuss improvements in minimizing blood transfusions, CPB circuit design, monitoring, perfusion techniques, temperature management, and myocardial protection, and then conclude with a brief discussion of how further systematic improvements can be made in these areas.

Noteworthy Literature published in 2017 for Congenital Cardiac Anesthesiologists

This review focuses on the literature published during the 13 months from December 2016 to December 2017 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Five themes are addressed during this time period and 100 peer-reviewed articles are discussed.