Children with single-ventricle physiology do not benefit from higher hemoglobin levels post cavopulmonary connection: results of a prospective, randomized, controlled trial of a restrictive versus liberal red-cell transfusion strategy

Abstract

Objective: To examine the impact of a restrictive vs. liberal transfusion strategy on arterial lactate and oxygen content differences in children with single-ventricle physiology post cavopulmonary connection. Children with single-ventricle physiology are routinely transfused postoperatively to increase systemic oxygen delivery, and transfusion thresholds in this population have not been studied.

Design: Prospective, randomized, controlled, clinical trial.

Setting: Pediatric cardiac intensive care unit in a teaching hospital.

Patients: Infants and children (n = 60) with variations of single-ventricle physiology presenting for cavopulmonary connection.

Interventions: Subjects were randomized to a restrictive (hemoglobin of < 9.0 g/dL), or liberal (hemoglobin of ≥ 13.0 g/dL) transfusion strategy for 48 hrs post operation. Primary outcome measures were mean and peak arterial lactate. Secondary end points were arteriovenous (C(a-v)o2) and arteriocerebral oxygen content (C(a-c)o2) differences and clinical outcomes.

Measurements and main results: A total of 30 children were in each group. There were no significant preoperative differences. Mean hemoglobin in the restrictive and liberal groups were 11 ± 1.3 g/dL and 13.9 ± 0.5 g/dL, respectively (p < .01). No differences in mean (1.4 ± 0.5 mmol/L [Restrictive] vs. 1.4 ± 0.4 mmol/L [Liberal]) or peak (3.1 ± 1.5 mmol/L [Restrictive] vs. 3.2 ± 1.3 mmol/L [Liberal]) lactate between groups were found. Mean number of red blood cell transfusions were 0.43 ± 0.6 and 2.1 ± 1.2 (p < .01), and donor exposure was 1.2 ± 0.7 and 2.4 ± 1.1 to (p < .01), for each group, respectively. No differences were found in C(a-v)o2, C(a-c)o2, or clinical outcome measures.

Conclusion: Children with single-ventricle physiology do not benefit from a liberal transfusion strategy after cavopulmonary connection. A restrictive red blood cell transfusion strategy decreases the number of transfusions, donor exposures, and potential risks in these children. Larger studies with clinical outcome measures are needed to determine the transfusion threshold for children post cardiac repair or palliation for congenital heart disease.