Impact of body weight on hemoglobin increments in adult red blood cell transfusion

Abstract

Background Though weight is a major consideration when transfusing blood in pediatric patients, it is generally not considered when dosing transfusions in adults. We hypothesized that the change in hemoglobin (Hb) concentration is inversely proportional to body weight when transfusing red blood cells (RBC) in adults. Methods A total of 13,620 adult surgical patients at our institution were assessed in this retrospective cohort study (2009–2016). Patients were stratified based on total body weight (kg): 40–59.9 (16.6%), 60–79.9 (40.4%), 80–99.9 (28.8%), 100–119.9 (11.3%), and 120–139.9 (2.9%). The primary outcome was the change in Hb per RBC unit transfused. Subgroup analyses were performed after stratification by sex (male/female) and the total number of RBC units received (1/2/≥3 units). Multivariable models were used to assess the association between weight and change in Hb. Results As patients' body weight increased, there was a decrease in the mean change in Hb per RBC unit transfused (40–59.9 kg: 0.85 g/dL, 60–79.9 kg: 0.73 g/dL, 80–99.9 kg: 0.66 g/dL, 100–119.9 kg: 0.60 g/dL, 120–139.9 kg: 0.55 g/dL; p < .0001). This corresponded with a 35% difference in the change in Hb between the lowest and highest weight categories on univariate analysis. Similar trends were seen after subgroup stratification. On multivariable analysis, for every 20 kg increase in patient weight, there was a ~6.5% decrease in the change in Hb per RBC unit transfused (p < .0001). Conclusions Patient body weight differentially impacts the change in Hb after RBC transfusion. These findings justify incorporating body weight into the clinical decision‐making process when transfusing blood in adult surgical patients.

Assessing predictors of futility in patients receiving massive transfusions

“…[10][11][12] We acknowledge that the decision to stop transfusing blood is multifactorial in nature and certainly should not be based on laboratory values alone. Patient characteristics, comorbidities, and the nature of the disease process itself should all be taken into consideration, as multiple studies have demonstrated that these factors not only influence the efficacy of RBC transfusion, 32,33 but also impact clinical outcomes. 6,34 It is also important to note that the trend of laboratory values should be considered in conjunction with the absolute values, and that laboratory tests be ordered judiciously based on the clinical picture.…”

From Unit to Dose: A Machine Learning Approach for Precise Prediction of Hemoglobin and Iron Content in Individual Packed Red Blood Cell Units

“…However, the transfusion effect, that is, Hb increase in patient's blood, varies significantly depending on several factors such as patient weight that correlates inversely to the Hb increase. [ 47 ] Moreover, we show here that the active agent of pRBCs, that is, Hb, varies substantially between pRBC units. This is even true for units of identical volume (Figure S2 , Supporting Information).…”

Modeling hemoglobin levels of patients chronically transfused with red blood cells

“…The actual ideal Hb incr per RBC unit depends on many factors, including patient blood volume, RBC unit Hb concentration, and actual RBC mass delivered. 5 Estimates of 24 h-Hb incr based on some of these key inputs has been previously reported. 6 The limitations and consequences of the mean ideal Hb incr of 1 g/dL/unit for each patient population is addressed further in the discussion section.…”

“…In this work 1 RBC unit was assumed to produce a mean ideal Hb incr of 1 g/dL. The actual ideal Hb incr per RBC unit depends on many factors, including patient blood volume, RBC unit Hb concentration, and actual RBC mass delivered 5 . Estimates of 24 h‐Hb incr based on some of these key inputs has been previously reported 6 .…”