A Conceptual Framework for Evaluating Patients Who May Need Red Cell Transfusion
Authors: Badawi Maha A. 
Published: November 2021

Abstract
Blood transfusion is an extremely common procedure that may be associated with significant risks, and orders for transfusion are common targets for "Choosing Wisely" Campaigns. Evaluating a patient for the need for red blood cells (RBCs) transfusion is not always a simple process. Although several guidelines are published to aid in determining which patients need a transfusion of RBCs, the decision can be complicated and must be individualized. Guidelines are frequently updated based on current published literature, but several elements must always be considered during patient evaluation for the possible need for RBC transfusion. We suggest using the acronym HOPES 2 C as a reminder of these elements (Hemoglobin level, Onset of anemia, Patient view, Extremes of age, Symptoms, Cause of anemia, and Co-morbidities).
Hemoglobin level must always be taken into account when evaluating a patient for the need for RBC transfusion. Many randomized clinical trials (RCTs) have shown that following a restrictive transfusion strategy (avoiding transfusion until Hb reaches 7 or 8 g/dL) is either equal or superior when compared with a liberal transfusion strategy (transfusion for Hb of 9-10 g/dL). The lower the hemoglobin, the more likely the patient will require a transfusion.
Onset of anemia: Patients with chronic anemia rarely require rapid transfusion, allowing time for investigation and provision of other effective treatments, such as iron or B12. These patients are also at increased risk of transfusion-associated circulatory overload. On the other hand, most patients with acute blood loss will require transfusion as part of resuscitation efforts.
Patient view: Patient caremust be guided by the individual patient's values and preferences.
Extremes of age: Patients at extremes of age (newborns and geriatric patients) may require different transfusion thresholds. This point needs further evaluation through RCTs.
Symptoms: The presence of hypotension, tachycardia, and end-organ dysfunction secondary to anemia indicate the need for transfusion.
Cause: Patients with anemia must not be transfused without an attempt to understand the cause of anemia. History, physical examination, and laboratory tests must be reviewed to evaluate for cause of anemia that may be correctable through effective alternatives to transfusions, such as iron or B12.
Co-morbidities: Patients with acute coronary syndrome or other diseases affecting oxygen delivery may need special consideration at the time of assessment. RCTs were published about a number of these settings, such as acute coronary syndrome, but further evidence is awaited for others.
It must be emphasized that this conceptual framework does not apply to patients with thalassemia and hemoglobinopathies, as care of these patients must follow disease-specific guidelines.
We hope that this conceptual framework helps physicians capture all assessment elements of a patient who may need a blood transfusion. We expect that this will reduce unnecessary transfusions while maintaining patient safety and quality of care.

Disclosures
No relevant conflicts of interest to declare.