Efficacy of a criterion-driven transfusion protocol in patients having pediatric cardiac surgery

Recommendations on RBC Transfusion in Infants and Children With Acquired and Congenital Heart Disease From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting literature for RBC transfusions in critically ill children with acquired and congenital heart disease developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of 38 international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

Experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations and research priorities for RBC transfusions in critically ill children. The cardiac disease subgroup included three experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA appropriateness method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

Twenty-one recommendations were developed and reached agreement. For children with myocardial dysfunction and/or pulmonary hypertension, there is no evidence that transfusion greater than hemoglobin of 10 g/dL is beneficial. For children with uncorrected heart disease, we recommended maintaining hemoglobin greater than 7-9.0 g/dL depending upon their cardiopulmonary reserve. For stable children undergoing biventricular repairs, we recommend not transfusing if the hemoglobin is greater than 7.0 g/dL. For infants undergoing staged palliative procedures with stable hemodynamics, we recommend avoiding transfusions solely based upon hemoglobin, if hemoglobin is greater than 9.0 g/dL. We recommend intraoperative and postoperative blood conservation measures. There are insufficient data supporting shorter storage duration RBCs. The risks and benefits of RBC transfusions in children with cardiac disease requires further study.

CONCLUSIONS

We present RBC transfusion management recommendations for the critically ill child with cardiac disease. Clinical recommendations emphasize relevant hemoglobin thresholds, and research recommendations emphasize need for further understanding of physiologic and hemoglobin thresholds and alternatives to RBC transfusion in subpopulations lacking pediatric literature.

Accuracy of predicted haemoglobin concentration on cardiopulmonary bypass in paediatric cardiac surgery: effect of different formulae for estimating patient blood volume

Introduction:

When applying a blood-conserving approach in paediatric cardiac surgery with the aim of reducing the transfusion of homologous blood products, the decision to use blood or blood-free priming of the cardiopulmonary bypass (CPB) circuit is often based on the predicted haemoglobin concentration (Hb) as derived from the pre-CPB Hb, the prime volume and the estimated blood volume. We assessed the accuracy of this approach and whether it may be improved by using more sophisticated methods of estimating the blood volume.

Patients and Methods:

Data from 522 paediatric cardiac surgery patients treated with CPB with blood-free priming in a 2-year period from May 2013 to May 2015 were collected. Inclusion criteria were body weight <15 kg and available Hb data immediately prior to and after the onset of CPB. The Hb on CPB was predicted according to Fick’s principle from the pre-CPB Hb, the prime volume and the patient blood volume. Linear regression analyses and Bland-Altman plots were used to assess the accuracy of the Hb prediction. Different methods to estimate the blood volume were assessed and compared.

Results:

The initial Hb on CPB correlated well with the predicted Hb (R2=0.87, p<0.001). A Bland-Altman plot revealed little bias at 0.07 g/dL and an area of agreement from -1.35 to 1.48 g/dL. More sophisticated methods of estimating blood volume from lean body mass did not improve the Hb prediction, but rather increased bias.

Conclusion:

Hb prediction is reasonably accurate, with the best result obtained with the simplest method of estimating the blood volume at 80 mL/kg body weight. When deciding for or against blood-free priming, caution is necessary when the predicted Hb lies in a range of ± 2 g/dL around the transfusion trigger.

Intraoperative tranexamic acid in pediatric bloodless cardiac surgery

OBJECTIVE

The aim of this study was to evaluate the clinical effects of intraoperative tranexamic acid administration in cardiac surgery without blood transfusion (bloodless cardiac surgery) in children.

METHODS

Seventy-one consecutive patients weighing less than 20 kg, who underwent bloodless cardiac surgery for simple atrial or ventricular septal defects at Kobe Children's Hospital from January 2011 to June 2013, were enrolled in this retrospective study. Tranexamic acid was administered during surgery from January 2012 (TXA group; n = 31), whereas it was not administered before January 2012 (control group; n = 40). Perioperative variables were compared between the TXA and control groups.

RESULTS

There were no significant differences in patient characteristics or preoperative data between the 2 groups. Serial changes in perioperative hemoglobin and hematocrit levels, mixed venous oxygen saturation, and regional cerebral oxygenation during cardiopulmonary bypass were significantly higher in the TXA group compared to the control group. There were significant reductions in operative time, dopamine dose, peak serum lactate level, intubation time, chest tube drainage and duration, and hospital stay in the TXA group.

CONCLUSIONS

Intraoperative tranexamic acid administration was effective for blood conservation, and improved postoperative clinical outcomes in pediatric bloodless cardiac surgery.

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.

Blood transfusion determines postoperative morbidity in pediatric cardiac surgery applying a comprehensive blood-sparing approach

OBJECTIVE

Recently we suggested a comprehensive blood-sparing approach in pediatric cardiac surgery that resulted in no transfusion in 71 infants (25%), postoperative transfusion only in 68 (24%), and intraoperative transfusion in 149 (52%). We analyzed the effects of transfusion on postoperative morbidity and mortality in the same cohort of patients.

METHODS

The effect of transfusion on the length of mechanical ventilation and intensive care unit stay was assessed using Kaplan-Meier curves. To assess whether transfusion independently determined the length of mechanical ventilation and length of intensive care unit stay, a multivariate model was applied. Additionally, in the subgroup of transfused infants, the effect of the applied volume of packed red blood cells was assessed.

RESULTS

The median length of mechanical ventilation was 11 hours (interquartile range, 9-18 hours), 33 hours (interquartile range, 18-80 hours), and 93 hours (interquartile range, 34-161 hours) in the no transfusion, postoperative transfusion only, and intraoperative transfusion groups, respectively (P < .00001). The corresponding median lengths of intensive care unit stay were 1 day (interquartile range, 1-2 days), 3.5 days (interquartile range, 2-5 days), and 8 days (interquartile range, 3-9 days; P < .00001). The multivariate hazard ratio for early extubation was 0.24 (95% confidence interval, 0.16-0.35) and 0.37 (95% confidence interval, 0.25-0.55) for the intraoperative transfusion and postoperative transfusion only groups, respectively (P < .00001). In addition, the cardiopulmonary time, body weight, need for reoperation, and hemoglobin during cardiopulmonary bypass affected the length of mechanical ventilation. Similar results were obtained for the length of intensive care unit stay. In the subgroup of transfused infants, the volume of packed red blood cells also independently affected both the length of mechanical ventilation and the length of intensive care unit stay.

CONCLUSIONS

The incidence and volume of blood transfusion markedly affects postoperative morbidity in pediatric cardiac surgery. These results, although obtained by retrospective analysis, might stimulate attending physicians to establish stringent blood-sparing approaches in their institutions.

Effects of a comprehensive blood-sparing approach using body weight-adjusted miniaturized cardiopulmonary bypass circuits on transfusion requirements in pediatric cardiac surgery

OBJECTIVES

Transfusion-free pediatric cardiac surgery remains a challenge, mainly owing to the mismatch between the cardiopulmonary bypass (CPB) priming volume and the infants' blood volume. Within a comprehensive blood-sparing approach, we developed body weight-adjusted miniaturized CPB circuits with priming volumes of 95, 110, and 200 mL for, respectively, infants weighing less than 3 kg, 3 to 5 kg and 5 to 16 kg. We analyzed the effects of this approach on transfusion requirements and risk factors predisposing for blood transfusion.

METHODS

A total of 288 children with body weights between 1.7 and 15.9 kg were included and divided into 3 groups: No transfusion, postoperative transfusion only, and intraoperative and postoperative transfusion. Groups were compared by analysis of variance or analysis of variance on ranks. Risk factors predisposing for transfusion were identified by multivariate logistic regression.

RESULTS

Of the infants, 24.7% required no transfusion, 23.6% received postoperative transfusion only and 51.7% received intraoperative and postoperative transfusion. Groups differed by age, body weight, and size and by duration of surgery, CPB, and aortic crossclamp (P<.00001). Body weight (P<.00001), CPB duration (P<.00001), and persisting cyanosis (P=.03) were predictors of intraoperative and postoperative transfusion, whereas body weight (P=.00095), reoperations (P=.0051), and cyanotic heart defects (P=.035) were associated with postoperative transfusion only.

CONCLUSIONS

Our blood-sparing approach allows for transfusion-free surgery in a substantial number of infants. The strongest predictors of transfusion requirement, body weight and complexity of surgery as reflected by CPB duration, are not amenable to further improvements. Better preservation of the coagulatory system might allow for reduction of postoperative transfusion requirements.

Minimizing intraoperative hemodilution by use of a very low priming volume cardiopulmonary bypass in neonates with transposition of the great arteries

OBJECTIVE

Owing to the mismatch between cardiopulomary bypass priming volume and infants' blood volume, pediatric cardiac surgery is often associated with transfusion of homologous blood, which may increase the risk of perioperative complications. Here we report the impact of a very low volume (95-110 mL) cardiopulmonary bypass circuit during arterial switch operations in neonates with transposition of the great arteries on blood requirements, tissue oxygenation, and patient outcome.

METHODS

Twenty-three consecutively treated neonates aged 2 to 17 days were treated with the blood-sparing approach. Asanguineous priming was used in all cases and packed red blood cells were added when hemoglobin concentration decreased below 7 g/dL. Cerebral and lower body tissue oxygenation was monitored by near-infrared spectroscopy. Intraoperative and postoperative transfusion, duration of ventilation and intensive care unit stay, wound infection, and 30-day mortality were assessed for patient outcome.

RESULTS

Intraoperative blood transfusion was necessary in 6 of 23 neonates. An additional 11 neonates received postoperative blood transfusions on the intensive care unit, leaving 6 infants who received no blood at all. Preoperative hemoglobin concentration was the only predictor for intraoperative transfusion requirement (11.6 ± 0.9 and 13.3 ± 0.4 g/dL in infants with and without intraoperative transfusion, respectively). Despite marked differences in hemoglobin concentrations between infants with and without transfusion, regional tissue oxygenation increased in both groups during cardiopulmonary bypass and returned to baseline at the end of surgery. In-hospital patient outcome was similar in both groups.

CONCLUSIONS

Transfusion-free complex cardiac surgery can be achieved even in neonates without jeopardizing tissue oxygenation or patient safety.

Red blood cell transfusion for infants with single-ventricle physiology

The purpose of this study was to assess how red blood cell (RBC) transfusions impact hemodynamic parameters in infants with single-ventricle lesions. This was a retrospective chart review. The setting was a pediatric cardiac intensive care unit at a tertiary care children's hospital. Fifty-nine patients <1 year of age with single-ventricle physiology who received a blood transfusion between December 2007 and April 2009 were analyzed. They received a total of 183 transfusions. Exclusion criteria included transfusions given within 72 h of cardiac surgery or transfusions given to patients with active bleeding. There were no interventions. The study population was divided into terciles based on pretransfusion hemoglobin (Hgb) concentration. The pretransfusion Hgb concentration in group A was 7.8 to 12.3 gm/dl, in group B was 12.4 to 13.2 gm/dl, and in group C was 13.3 to 15.7 gm/dl. Heart rate, blood pressure, arterial saturation, and cerebral near-infrared spectroscopy (cNIRS) values before transfusion, as well as at 1, 2, 4, 8, and 12 h after transfusion, were collected. There was significant improvement in diastolic blood pressure, arterial saturation, and cNIRS in group A after 12 h. Transfusions given in group B also resulted in improvement in diastolic blood pressure and arterial saturation, with less robust response of cNIRS. In group C, only arterial saturation values increased significantly. RBC transfusions can improve hemodynamics and markers of oxygen delivery in infants with single-ventricle physiology, but further studies are needed to determine an optimal Hgb level in this population. Interventions to increase Hgb above this level may be of limited benefit.

Pediatric cardiac surgery without homologous blood transfusion, using a miniaturized bypass system in infants with lower body weight

OBJECTIVE

We have established a low-priming volume cardiopulmonary bypass system for pediatric heart surgery to avoid homologous blood transfusion. The priming volume of our system is down to 140 mL for patients weighing less than 7 kg. We can prime the bypass circuits without blood products for patients weighing more than 4 kg.

METHODS

Seventy consecutive patients weighing 4 to 7 kg underwent heart surgery with a bloodless prime from October 2003 to September 2006. The type of procedures (Risk Adjustment in Congenital Heart Surgery category) included the following: category 1: atrial septal defect (n = 3); category 2: ventricular septal defect, tetralogy of Fallot, bidirectional Glenn shunt, and others (n = 55); category 3: atrioventricular septal defect, double-outlet right ventricle, and others (n = 8); category 4: Rastelli procedure for transposition of the great arteries (n = 3); and category 6, Damus-Kaye-Stansel procedure (n = 1). Transfusion criteria were hematocrit less than 20%, mixed venous oxygen saturation less than 70%, regional cerebral oxygenation less than 50%, and plasma lactate level greater than 4.0 mmol/L during bypass.

RESULTS

The mean age and body weight were 7.3 +/- 5.4 months and 5.4 +/- 0.8 kg, respectively. Forty-five patients (64%) underwent transfusion-free procedures. Preoperative hematocrit, age, body weight, complexity of procedure and cardiopulmonary bypass time were compared between patients with and without transfusion. Bypass time and Risk Adjustment in Congenital Heart Surgery risk category in patients with transfusion were significantly greater than those in patients without (P < .0001, and P < .05, respectively). Body weight in patients without transfusion was significantly greater than that in patients with (P < .01). In multiple regression analysis, the determinants of blood transfusion were the bypass time and body weight (odds ratio 1.026, 95% confidence interval 1.011-.040, P < .0001, and odds ratio 0.366, 95% confidence interval 0.171-0.785, P < .01).

CONCLUSIONS

It is possible to do complex transfusion-free procedures safely for patients weighing more than 4 kg by using the low-priming volume circuit. The limiting factors of bloodless heart surgery are not preoperative hematocrit and complexity of procedure but the cardiopulmonary bypass time and the patient's body weight.

The Efficacy of Preoperative Administration of a Single Dose of Recombinant Human Erythropoietin in Pediatric Cardiac Surgery

BACKGROUND

Preoperative autologous blood donation with recombinant human erythropoietin (rHuEPO) is effective in adults. However, there are problems concerning the blood access, cost, and blood storage in children. The purpose of this study was to evaluate the efficacy of administering a single dose of rHuEPO without blood donation in children undergoing pediatric cardiac surgery.

METHODS

Eighty-two children (72 with noncyanotic heart disease, and 10 with cyanotic heart disease) whose hematocrit values were less than 45% were included in this prospective, nonrandomized study. The children were divided into 3 groups: group E0 (n = 20) was not treated with rHuEPO and iron sulfate; group E2 (n = 27) was treated with 200 IU/kg of rHuEPO and 2 mg/kg of iron sulfate; and group E4 (n = 35) was treated with 400 IU/kg of rHuEPO and 4 mg/kg of iron sulfate. Administration of rHuEPO was performed subcutaneously 7 days before the operation. The hematological and iron parameters were measured perioperatively.

RESULTS

A lower proportion of children treated with rHuEPO (group E2, 14.8%; group E4, 22.9%) than children without rHuEPO (group E0, 40.0%) were exposed to RBC transfusions; however, there was no significance. The elevations of the hematocrit levels were 0.7% in group E0, 1.3% in group E2, and 1.9% in group E4. The elevation of the hematocrit was greater in patients with anemia (hematocrit < or =37%).

CONCLUSIONS

Although the effectiveness for avoiding transfusion was not clear, the administration of a single dose of rHuEPO without autologous blood donations had an effect by increasing hematocrit levels.

Blood Conservation in Pediatric Anesthesia

This review focuses on perioperative blood conservation techniques and the role of transfusion triggers and algorithms, preoperative autologous donation, acute normovolemic hemodilution, intraoperative blood salvage, deliberate hypotension, and preoperative recombinant human erythropoietin in avoiding allogeneic blood transfusion in pediatric patients.