Red blood cell mass: indications and features of transfusion

Red blood cell (RBC) concentrate is a complex of red blood cells obtained from donor blood by removing most of the plasma and some of the white blood cells. The purpose of transfusion is to restore oxygen transport in cases of symptomatic anemia or acute blood loss, when the body's own compensatory mechanisms are exhausted. Unlike whole blood, this component provides targeted red blood cell replenishment without excess plasma, reducing the risk of volume overload. Standardized descriptions of the component, including composition, storage, and general principles of use, are provided in the current "Circle of Information" on the Use of Blood and Blood Components. [1]

Typically, one standard dose of packed red blood cells in an adult weighing approximately 70 kg increases hemoglobin concentration by approximately 1 gram per deciliter. This guideline is used as a rule of thumb for dose planning and reassessment of the effect after each unit. If a slow infusion is required, it is recommended to order smaller aliquoted doses to avoid exceeding the maximum infusion time. [2]

Storage and properties depend on the preservative solution. With modern additive solutions, the shelf life is typically up to 42 days at 1 to 6 degrees Celsius, while with citrate-phosphate-dextrose-adenine solution, the shelf life can be up to 35 days. These parameters are important for logistics and quality control, but "freshness" alone does not improve outcomes for most patients compared to standard first-in, first-out dispensing. [3]

When to transfuse: thresholds and clinical indications

The current strategy is "restrictive": transfusion is considered at a hemoglobin concentration of approximately 7 grams per deciliter in hemodynamically stable adults, and at 8 grams per deciliter in patients with cardiovascular disease or in perioperative situations in orthopedics and cardiac surgery. The decision is always made based on symptoms of tissue hypoxia, comorbidities, and the dynamics of blood loss, rather than on a single blood test result. [4]

National transfusion guidelines emphasize a "one unit, then reassess" approach: transfuse one unit, remeasure hemoglobin, and assess symptoms before administering the next. This approach reduces overall exposure to donor blood and the risk of complications while maintaining clinical effectiveness. [5]

In acute coronary syndrome, the optimal threshold remains a subject of debate. Recent research suggests that a more liberal approach, maintaining hemoglobin levels closer to 10 grams per deciliter, may numerically reduce ischemic events but does not provide a statistically significant benefit. Therefore, in real-world practice, the threshold is guided by ischemic symptoms and hemodynamics, adhering to moderately restrictive limits. [6]

For children and patients weighing less than 50 kg, calculated doses are administered in milliliters per kilogram. A standard range of 10-15 milliliters per kilogram typically increases hemoglobin by 10-20 grams per liter, depending on the component's hematocrit, allowing for precise volume selection in small patients and avoiding volume overload. [7]

How to Prescribe Dose and Rate: Practical Steps

For an adult weighing approximately 70 kg, a hemoglobin increase of 1 gram per deciliter per standard dose is targeted. For severe symptomatic anemia, start with a single dose, then reassess the clinical effect and laboratory parameters. To minimize the risk of volume overload, especially in the elderly or with heart failure, a slow regimen and diuretic prophylaxis as clinically indicated are advisable. [8]

The infusion rate is adjusted to the circulatory status, but each unit of the component should be fully administered no longer than 4 hours after the system is connected. If a longer infusion is anticipated, smaller portions of the dose are ordered in advance. At the beginning of the transfusion, close monitoring is essential to detect any reactions promptly. [9]

For children, the dose is calculated based on body weight. Using a range of 10-15 milliliters per kilogram allows for predicting hemoglobin increases and planning a safe rate, including through syringe pumps in newborns and infants. In pediatrics, strict blood group identification and minimizing donor exposure are particularly important to reduce the risk of immunization. [10]

In iron deficiency management programs, it is recommended to initiate iron therapy before elective surgery, and in cases of intolerance or time constraints, consider intravenous iron supplements and, if indicated, erythropoiesis stimulating agents. This reduces the risk of transfusion and improves outcomes during elective surgery. [11]

Pretransfusion testing and component selection

Before transfusion, the ABO blood group and Rh factor are confirmed, antibody screening is performed, and a cross-test is conducted. If the screening is negative, electronic cross-checking is permitted according to approved protocols. In life-threatening situations, it is permissible to begin with untested red blood cell mass of type O or a group corresponding to the patient, with mandatory revision of testing as the blood stabilizes. [12]

The choice of blood type and Rh factor depends on gender and reproductive status. In women of childbearing age, Rh-negative red blood cells are preferred if there is no time for full testing to reduce the risk of immune sensitization. Once the results are available, a fully compatible component is selected based on the antibodies detected. [13]

In cases of massive blood loss, massive transfusion protocols with a balanced ratio of red blood cells, plasma, and platelets (approximately one to one) are used. This approach reduces mortality from exanguination and improves hemostasis compared to more "plasma-poor" regimens. Calcium, temperature, and acid-base balance are monitored simultaneously. [14]

In institutions where low-titer anti-A and anti-B whole blood kits are available, initial resuscitation in trauma patients may be performed before the patient's group is determined according to local safety standards. This requires clear procedures for selection and labeling based on antibody titers. [15]

Modified Components: When Special Requirements Are Needed

Leukofiltered red blood cell mass is now the standard in most countries. Preventive leukoreduction reduces the risk of febrile non-hemolytic reactions, decreases the transmission of cytomegalovirus, and decreases the likelihood of immunization to leukocyte antigens. For many patients, leukofiltration provides a "safe" level for cytomegalovirus, comparable to that of cytomegalovirus-seronegative components. [16]

Irradiated red blood cell (RBC) concentrate is indicated for the prevention of transfusion-associated graft-versus-host disease (GVHD) in immunocompromised patients, during intrauterine and neonatal transfusions, and in a number of hematological conditions. Following irradiation, the shelf life of the component is reduced to 28 days from the date of irradiation or the original shelf life, if shorter.[17]

Washed red blood cell mass is used in severe recurrent allergic reactions, including in patients with immunoglobulin A deficiency with clinically significant antibodies to immunoglobulin A, as well as in exchange transfusions in newborns. The product, washed in an open system, should be transfused within 24 hours. [18]

Protection against cytomegalovirus is especially important for pregnant women and their fetuses. In obstetrics, it is common to use "CMV-safe" components, with preference given to CMV-seronegative components where available, or leukocyte-filtered components as an acceptable alternative. Specific requirements depend on the local blood service. [19]

Reactions and Safety: Recognition and Prevention

Transfusion-associated volume overload presents with dyspnea, hypoxemia, and signs of heart failure during or shortly after transfusion. Risk is increased in the elderly, those with chronic kidney disease, and those with heart failure. Prevention includes a "one unit per dose" strategy, slow rates, dose splitting, and appropriate use of diuretics. Standard Hemovigilan criteria are used for diagnosis. [20]

Transfusion-associated acute lung injury (TALI) is noncardiogenic pulmonary edema that occurs within 6 hours of transfusion. Current classifications distinguish between those with and without preexisting respiratory failure. Prevention involves donor selection and reduction of exposure to potentially immunoreactive plasma. Treatment includes supportive oxygen therapy and ventilation.

An acute hemolytic reaction is usually associated with ABO incompatibility due to identification errors. Immediately discontinue the transfusion, maintain the system, notify the laboratory, and initiate supportive measures. Delayed hemolytic reactions are often milder but require monitoring for a decrease in hemoglobin and an increase in bilirubin. [21]

Febrile non-hemolytic and allergic reactions are usually mild and respond to slowing the infusion, antipyretics, or antihistamines. In cases of severe anaphylaxis or documented immunoglobulin A deficiency with clinically significant antibodies to immunoglobulin A, further transfusions are planned using washed components or components deficient in immunoglobulin A, depending on availability. [22]

Special patient groups and controversies

In cardiac surgery and major orthopedic procedures, periprocedural thresholds are often slightly higher than in general therapy; however, even here, current guidelines generally support restrictive strategies tailored to the individual patient's risk of ischemia. Integrating principles of patient-centered blood management reduces the need for transfusions and complications, including through correction of iron deficiency and blood-sparing protocols. [23]

In patients with sickle cell disease, indications for simple or exchange transfusion are determined by clinical presentation, the targeted reduction of abnormal hemoglobin levels, and stroke prevention. In this cohort, phenotypic or genotypic extended matching is particularly important to reduce the risk of alloimmunization. The general sections on red blood cell dosing and safety remain relevant. [24]

The debate over "old" versus "fresh" red blood cells has been resolved by large studies: in intensive care patients and in mixed cohort samples, early distribution of "fresher" units did not improve outcomes compared to standard logistics. Therefore, routine prioritization of "fresh" units without specific indications is unnecessary.

In preparation for elective surgery, correction of iron deficiency and treatment of concomitant anemia reduce the need for transfusions. In some studies in patients undergoing major abdominal surgery, the effect of preoperative iron infusions was inconclusive, so the decision is made on an individual basis, assessing the time before surgery and the patient's tolerability of oral therapy. [25]

Table 1. Main characteristics of red blood cell mass

Parameter	Typical value	Comment
Volume of one unit	about 250-350 milliliters	Depends on the method of preparation and the additive solution. [26]
Hematocrit	about 55-65% in additive solutions, 65-80% in citrate-phosphate-dextrose-adenine solution	Affects the expected increase in hemoglobin. [27]
Shelf life	up to 42 days in additive solutions, up to 35 days in citrate-phosphate-dextrose-adenine	At temperatures from 1 to 6 degrees Celsius. [28]
Expected increase in hemoglobin	about 1 gram per deciliter in an adult per unit	Practical guideline for dosing. [29]
Maximum infusion time	no more than 4 hours per unit	If necessary, smaller portions of the dose. [30]

Table 2. Threshold values for initiating transfusion in adults

Clinical situation	Recommended hemoglobin target	Notes
Hemodynamically stable patients without active ischemia	about 7 grams per deciliter	Restrictive strategy. [31]
Orthopedic or cardiac surgery, presence of cardiovascular disease	about 8 grams per deciliter	Consider symptoms and blood loss. [32]
Acute coronary syndrome	personalized, usually 8-10 grams per deciliter	Data suggest potential benefit at higher levels, but without statistical significance.[33]
The one-unit-revaluation approach	always use unless there is massive bleeding	Reduces exposure to donor blood. [34]

Table 3. Dosage and expected effect

Patient group	Dose	Expected increase in hemoglobin
Adults	1 standard unit	about 1 gram per deciliter 30-60 minutes after infusion with subsequent monitoring. [35]
Children and adolescents weighing less than 50 kilograms	10-15 milliliters per kilogram	about 10-20 grams per liter, depending on the hematocrit of the component. [36]
Newborns and infants	individually, in small portions	strict monitoring of electrolytes and temperature is required.[37]

Table 4. Compatibility selection and emergency situations

Scenario	Recommended action	Base
Planned transfusion with negative antibody screening	Electronic cross-checking according to the protocol, fully compatible	Reduces time without compromising safety. [38]
Life-threatening, tests not ready	Start with group O red blood cells, then move to fully compatible	Permitted subject to local procedures. [39]
Women of childbearing age with no data available	Rh-negative red blood cells are preferred.	Reducing the risk of immune sensitization. [40]
Massive blood loss	A protocol with a component ratio of approximately one to one to one	Improving hemostasis and survival. [41]

Table 5. Component modifications and indications

Modification	Main indications	Peculiarities
Leukofiltration	Reduction of febrile reactions, risk of cytomegalovirus transmission, immunization to leukocyte antigens	Standard for most patients. [42]
Irradiation	Prevention of transfusion-associated graft-versus-host disease in immunocompromised individuals, intrauterine and neonatal transfusions, and a range of hematological conditions	The shelf life after irradiation is limited to 28 days. [43]
Washing	Severe allergic reactions, immunoglobulin A deficiency with antibodies, exchange transfusions in newborns	The product washed in an open system is usable for 24 hours. [44]
“Safe for cytomegalovirus”	Pregnancy, fetus, neonatology, transplantation	Seronegative for cytomegalovirus or pre-preventively leukocyte-filtered samples are acceptable. [45]

Table 6. Common transfusion reactions and management strategies

Reaction	Key Features	Prevention and action
Transfusion-related volume overload	Dyspnea, hypoxemia, signs of pulmonary circulation overload	Slow rate, one unit with re-evaluation, split dose, diuretics when indicated. [46]
Transfusion-associated acute lung injury	Non-cardiogenic pulmonary edema within 6 hours	Donor selection, reduction of plasma exposure, maintenance therapy.
Acute hemolytic reaction	Fever, pain, hemoglobinuria, hypotension	Stop transfusion immediately, laboratory investigation, support. [47]
Febrile non-hemolytic, allergic	Chills, hives, itching, mild fever	Leukofiltration reduces the risk; in severe allergies, washed components are used. [48]

Table 7. Storage and “age” of red blood cells: what is important in practice

Question	Current state of knowledge	Practice
Is there any benefit to "very fresh" red blood cells?	Large studies have shown no benefit over standard issuance	The first-in, first-out principle remains acceptable.
Shelf life after irradiation	Limited to 28 days from the date of irradiation or the original period, if shorter	Consider when ordering for patients requiring irradiated components. [49]
Shelf life after washing	In an open system - 24 hours	Plan logistics for the clinical task. [50]