From the Guidelines
A transfusion of 10 ml.kg-1 of RBC should increase Hb by approximately 20 g.l-1 in pediatric patients. This is based on the most recent and highest quality study available, which provides guidance on the use of blood components in children 1. When considering the increase in hemoglobin (Hgb) with packed red blood cells (pRBC) transfusion in pediatric patients, several factors come into play, including the patient's weight, the volume of blood transfused, and the hematocrit of the transfused unit.
Key Considerations
- The volume of blood to be administered requires modification depending on the size of the patient, with blood in children prescribed in volume rather than number of units 1.
- A dose of 10 ml.kg-1 of RBC is recommended, which should increase Hb by approximately 20 g.l-1 1.
- The response to transfusion should be assessed by checking a post-transfusion hemoglobin level, typically 1-2 hours after completion of the transfusion.
- Factors that may reduce the expected Hgb rise include ongoing bleeding, hemolysis, splenic sequestration, or fluid shifts.
Transfusion Thresholds
- Transfusion thresholds generally being lower (7-8 g/dL) for stable patients and higher for those with cardiac disease or acute blood loss 1.
- Higher transfusion thresholds are often applied to neonates and children with congenital heart disease 1.
- ‘Restrictive’ approaches to transfusion are appropriate for almost all children older than 3 months of age 1.
Administration
- Devices for vascular access and rapid administration of blood should be appropriate for the size of the child and rate of blood loss 1.
- Children are at particular risk of electrolyte imbalance and hypothermia during rapid administration of blood products 1.
From the Research
Increase in Hemoglobin (HGB) with PRBC Transfusion
- The increase in HGB with PRBC transfusion can vary depending on several factors, including the patient's initial HGB level, the number of units transfused, and the patient's weight 2, 3.
- A study published in 2008 found that each unit of PRBCs is expected to raise circulating HGB by approximately 1 g/dL 2.
- Another study published in 2007 found that the correlation gradient between mL per kg blood transfused and increase in HGB was 5.02, and that 10 mL/kg of PRBCs can be expected to increase HGB by approximately 2 g/dL 3.
- A study published in 2018 found that the average increase in HGB after PRBC transfusion was 1.91 g/dL, with a mean of 4.23 units of PRBCs transfused over 7 days 4.
Factors Affecting HGB Increase
- The initial HGB level can affect the increase in HGB after PRBC transfusion, with lower initial HGB levels resulting in a greater increase in HGB 2, 5.
- The number of units transfused can also affect the increase in HGB, with more units resulting in a greater increase in HGB 2, 3.
- Patient weight can also be a factor, with the equation weight (kg) x increment in HGB (g/dL) x 3/(hematocrit level of RBCs) used to calculate transfusion volumes 3.
Pediatric Patients
- There is limited specific data on the increase in HGB with PRBC transfusion in pediatric patients.
- However, the study published in 2007 found that the correlation gradient between mL per kg blood transfused and increase in HGB was consistent across different patient weights and ages 3.
- It is likely that the increase in HGB with PRBC transfusion in pediatric patients will be similar to that in adult patients, with the same factors affecting the increase in HGB 2, 3, 4, 5.