Transfusion Strategies in Pediatric Cardiothoracic Surgery

Objective: To compare mean post-operative arterial lactate levels, oxygen utilization, and outcome measures in pediatric patients undergoing cavopulmonary connection managed with two different red blood cell transfusion strategies.

Methods: We propose a prospective, randomized clinical trial of sixty-six pediatric patients with cyanotic, complex congenital cardiac disease undergoing cavopulmonary connection as their operative repair. Thirty-three patients will be randomly assigned to a low Hb strategy of transfusion, in which red cells are transfused if the hemoglobin concentration falls below 9.0 g/dL, and hemoglobin concentrations are maintained about 8.5 g/dL. Thirty-three additional patients will be randomly assigned to the high Hb transfusion strategy, where red cells are transfused if the hemoglobin concentration falls below 13.0 g/dL, and hemoglobin concentrations are maintained about 12.5 g/dL. The primary endpoint will be comparison of mean arterial lactate levels from 8 to 72 hours post-operatively. The secondary endpoints will be oxygen utilization reflected by the arterio-venous oxygen difference (AV-difference) and arterio-cerebral oxygen difference (AC-difference). Measures of oxygen utilization will be derived from arterial oxygen saturation (SaO2), mixed venous oxygen saturation (SvO2), and cerebral oxygen saturation (ScO2) collected at various time points throughout the study. Tertiary outcome measures will be length of mechanical ventilation, length of oxygen use and of vasoactive agent administration, length pediatric cardiac intensive care unit (PCICU) admission, volume of blood transfused, and mortality. Data from each group will be compared using analysis of variance to assess for the presence of a difference between the two transfusion strategies. If a significant difference between the two groups exists, T-tests will be performed to compare data points between each group to assess for a significant difference.

Hypothesis: A more restrictive (low Hb) strategy of red cell transfusion will be as effective as, and possibly superior to, the historical (high Hb) approach. Allowing a lower Hb concentration will decrease RBC donor exposure and may decrease the known complications of RBC transfusions. We postulate that no significant difference will exist between the two transfusion groups in regards to hemodynamic and cardiopulmonary status (as evidenced by mean lactate levels) and oxygen utilization.

Inclusion criteria

• 4 months to 6.99 years of age
• surgical candidates for cavopulmonary connection
• English speaking

Exclusion criteria

• presence of known bleeding disorder
• presence of known coagulopathy
• age < 4 months
• age > 7 years
• non-English speaking