RBC transfusions in children requiring intensive care admission after traumatic injury*

Recommendations on RBC Transfusions in Critically Ill Children With Acute Respiratory Failure 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 bleeding developed by the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

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

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations as well as research priorities for RBC transfusions in critically ill children. The respiratory subgroup included six 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

Transfusion and Anemia Expertise Initiative experts developed seven recommendations focused on children with acute respiratory failure. All recommendations reached agreement (> 80%). Transfusion of RBCs in children with respiratory failure with an hemoglobin level less than 5 g/dL was strongly recommended. It was strongly recommended that RBCs not be systematically administered to children with respiratory failure who are hemodynamically stable and who have a hemoglobin level greater than or equal to 7 g/dL. Experts could not make a recommendation for children with hemodynamic instability, with severe hypoxemia and/or with an hemoglobin level between 5 and 7 g/dL. Specific RBC transfusion strategies using physiologic-based metrics and biomarkers could not be elaborated.

CONCLUSIONS

The Transfusion and Anemia Expertise Initiative Consensus Conference developed specific recommendations regarding RBC transfusion management in critically ill children with respiratory failure, as well as recommendations to guide future research. Clinical recommendations emphasize relevant hemoglobin thresholds. Research recommendations emphasize the need to identify appropriate physiologic thresholds, suggest a better understanding of alternatives to RBC transfusion, and identify the need for better evidence on hemoglobin thresholds that might be used in specific subpopulations of critically ill children.

Determinants of red blood cell transfusion in pediatric trauma patients admitted to the intensive care unit

BACKGROUND

There are no well-designed prospective studies evaluating transfusion practices in pediatric trauma. We sought to describe red blood cell (RBC) transfusion practices in trauma patients who were admitted to a pediatric intensive care unit (PICU).

STUDY DESIGN AND METHODS

This study is a post-hoc analysis of a prospective, 6-month observational study in 30 PICUs. We studied a total of 580 patients aged less than 18 years who had been admitted to a PICU for more than 48 hours, including 95 who were trauma patients.

RESULTS

Trauma patients more frequently received transfusion before PICU admission (p < 0.001), were older (p < 0.0001), and more frequently were mechanically ventilated (p = 0.05). In the PICU, trauma patients received more transfusions (55% vs. 37%; p < 0.001), although admission hemoglobin levels were similar in both groups (p = 0.86). The mean (± standard deviation) pretransfusion hemoglobin level in the PICU was 9.0 ± 2.4 g/dL for trauma patients compared with 8.3 ± 2.4 g/dL for nontrauma patients (p = 0.09). Among the trauma patients, transfusion was associated with younger age, higher Pediatric Logistic Organ Regression scores, mechanical ventilation, bleeding, and transfusion before PICU admission. Multivariate regression demonstrated that receiving an RBC transfusion before admission was strongly associated with receiving a blood transfusion in the PICU (p = 0.008).

CONCLUSION

Trauma patients are at high risk for receiving an RBC transfusion both before and during their PICU stay, despite a similar transfusion threshold compared with nontrauma patients. Transfusion before PICU admission is a strong determinant, suggesting ongoing bleeding that will require re-transfusion. Further studies are needed to evaluate whether a restrictive transfusion strategy can safely be considered in these patients.

Red blood cell transfusion is associated with increased hemolysis and an acute phase response in a subset of critically ill children

In healthy adults, transfusion of older stored red blood cells (RBCs) produces extravascular hemolysis and circulating non-transferrin-bound iron. In a prospective, observational study of critically ill children, we examined the effect of RBC storage duration on the extent of hemolysis by comparing laboratory measurements obtained before, and 4 hr after, RBC transfusion (N = 100) or saline/albumin infusion (N = 20). Transfusion of RBCs stored for longer than 4 weeks significantly increased plasma free hemoglobin (P < 0.05), indirect bilirubin (P < 0.05), serum iron (P < 0.001), and non-transferrin-bound iron (P < 0.01). However, days of storage duration poorly correlated (R(2) <0.10) with all measured indicators of hemolysis and inflammation. These results suggest that, in critically ill children, most effects of RBC storage duration on post-transfusion hemolysis are overwhelmed by recipient and/or donor factors. Nonetheless, we identified a subset of patients (N = 21) with evidence of considerable extravascular hemolysis (i.e., increased indirect bilirubin ≥0.4 mg/dL). In these patients, transfusion-associated hemolysis was accompanied by increases in circulating non-transferrin-bound iron and free hemoglobin and by an acute phase response, as assessed by an increase in median C-reactive protein levels of 21.2 mg/L (P < 0.05). In summary, RBC transfusions were associated with an acute phase response and both extravascular and intravascular hemolysis, which were independent of RBC storage duration. The 21% of transfusions that were associated with substantial hemolysis conferred an increased risk of inducing an acute phase response.