In a blood transfusion, blood or its components are transferred from a donor to a recipient. It is a medical procedure for individuals who have experienced significant blood loss, have anemia, or require extra blood components. Blood transfusion replenishes or replaces blood components in individuals who require medical intervention that can save lives and improve patients’ conditions.

Process of blood transfusion

If your doctor believes you or a loved one may need a blood transfusion, there are several steps to expect before and after the blood transfusion process to ensure the safe and effective transfer of blood. Some of the general steps are:

Pre-transfusion testing

To evaluate the needs and medical condition of the recipient, healthcare professionals conduct complete blood assessments and determine the compatible blood components, blood type, and any additional precautions or risks.

Donor blood screening and testing

Donated blood undergoes the process of screening and blood tests to ensure its safety and compatibility. Donor plasma is tested for deadly diseases such as HIV, hepatitis B, hepatitis C, syphilis, West Nile virus, and other bacterial contamination. Donor blood is also cross-checked for compatibility with blood type and blood group, antibodies, and other risk factors.

Blood typing and compatibility

The recipient's blood type (A, B, AB, or O) and Rh factor (positive or negative) are essential to evaluate. Blood typing helps to determine whether the donor's plasma and the patient set to receive blood have adequate compatibility. Crossmatching reduces the risk of adverse reactions such as allergic reactions, delayed hemolytic reaction, and other life-threatening transfusion reactions.

Blood extraction

Once a compatible donor is found and matched with the recipient, the whole blood or blood components (such as red blood cells, platelets, or plasma) may be collected from the donor.

Transfusion of blood

The blood is administered through a sterile tube system to the recipient. A sterile tubing system contains a blood bag that transfuses blood through a needle or catheter into the recipient's vein. The rate of transfusion is pre-set to minimize any potential risks and hazards. The transfusion rate is closely monitored to ensure a controlled and safe delivery of blood.

Post-transfusion monitoring

Monitoring and observation of vital signs like blood pressure, heart rate, and oxygen levels is essential. This will help to evaluate any adverse reactions or complications to the recipient.

Blood transfusion benefits

Blood transfusions have many benefits that improve overall health and well-being. Some of them are:

Restores blood volume and oxygen-carrying capacity

Blood transfusion helps restore blood volume in blood loss due to trauma or surgical procedures. Blood transfusion regulates blood pressure and circulation, helping blood vessels carry oxygen to various body organs and tissues.

Treats anemia and blood loss

Transfusing blood helps to treat various types of anemia, meaning low levels of red blood cells or hemoglobin. A blood transfusion replaces lost blood due to certain injuries and diseases and prevents complications or risks associated with low blood volume and unbalanced oxygen supply.

Improves vital signs and symptoms

Blood transfusion can alleviate mild symptoms such as fatigue and weakness, as well as severe symptoms, such as difficulty breathing, and clammy skin.

Works as a supportive treatment

Blood transfusion offers supportive treatment for various medical conditions, such as cancer and blood disorders characterized by low blood count. They also enhance low energy levels due to chemotherapy or radiation. 

Effects of blood transfusion on your body

Improve circulation and organ function

The performance of body organs depends on adequate blood volume so that they carry oxygen inside the body. Transfusion replenishes blood volume and promotes the optimal performance of these organs by ensuring sufficient oxygen levels and nutrients. 

Replenish red blood cells

Transfusions help replenish red blood cells (RBCs), which carry oxygen to body tissues. Additional blood cells increase the oxygen-carrying capacity of the blood. Blood cell replenishment addresses anemia and acute blood loss, and helps restore energy levels.

Recipient's immune system response to transfused blood

The person’s immune system reacts with the blood they received. There are various types of reactions to transfused blood. They are discussed separately below. 

Hemolytic transfusion reaction

A hemolytic reaction is when the immune system attacks and destroys the red blood cells. This reaction may lead to fever, chills, jaundice, kidney damage, chest or back pain, hemoglobinuria (presence of hemoglobin in the urine), jaundice, shock, and even death.

How the immune system attacks transfused red blood cells

The recipient’s immune system launches an immune reaction when its system recognizes the donor blood RBCs as foreign bodies. The antigens in the donated blood stimulate this type of response when the same antigens are absent in the recipient’s blood. The recipient's immune system produces antibodies due to these antigens and destroys the transfused red blood cells. This reaction happens due to certain blood disorders or previous blood typing incompatibility.

Allergic reaction

An allergic reaction can happen due to the presence of plasma proteins in the donated blood. These blood transfusion reactions are characterized by mild symptoms like itching and hives, as well as life-threatening symptoms like difficulty breathing, and anaphylaxis.

Delayed hemolytic reactions

These reactions are characterized by low hemoglobin levels, fever, and jaundice. Delayed hemolytic reactions occur when the recipient's immune system has previous exposure to the antigen from multiple blood transfusions or pregnancy. 

Compatibility and blood typing

It is crucial to transfuse compatible blood to prevent adverse reactions. The ABO and Rh blood group systems ensure compatibility between the donor's blood and the recipient's blood. All the parameters must match the blood types to reduce the risk of incompatible transfusions that may lead to potential complications and risks. 

Risk factors associated with incompatible blood transfusions

Mismatching or incompatibility in choosing the right blood can lead to various risks and complications, such as 

• Acute hemolytic transfusion reaction
• Delayed hemolytic transfusion reaction
• Other complications associated with non-immune-mediated reactions, such as transfusion-related acute lung injury (TRALI), allergic reactions, and transfusion-associated circulatory overload (TACO)

Potential Blood Transfusion Risks

While there are many benefits to a blood transfusion, the procedure comes with some risks as well. These include:

Transmission of infectious diseases

Blood transfusions rarely transmit infectious diseases through donated blood. Screening for HIV, hepatitis B and C, and other infectious agents, are required to reduce this risk.

Precautions include the prior screening of donor plasma, proper handling and storage of blood products, and following protocols to ensure safe and effective blood transfusions without bacterial contamination. 

Iron overload

Iron load or hemochromatosis happens when repeated blood transfusion accumulates too much iron in the body. It can damage the endocrine system, liver and heart functions. Some common symptoms include fatigue, arthritis, abdominal pain, loss of sex drive or impotence, weakness, weight loss, skin color changes (bronzing), diabetes, and increased risk of infections. 

Blood clotting factors and the risk of blood clot formation

Certain clotting factors can become part of the recipient's blood after transfusion. This may increase the risk of blood clot formation leading to deep vein thrombosis, pulmonary embolism, or even stroke. 

Lung injury and respiratory complications

Blood transfusion can rarely cause transfusion-related acute lung injury (TRALI), characterized by respiratory distress and lung injury.

Kidney failure and its impact on the body

Blood transfusion can contribute to kidney failure or injury for individuals with compromised kidney functions.

Low blood pressure and related symptoms

Blood transfusions affect blood pressure, potentially leading to low blood pressure, which can cause dizziness and fainting.

Chest pain and severe back pain 

A blood transfusion may rarely cause chest pain and backache during or after a transfusion and requires prompt medical attention. 

Precautions and Monitoring

To ensure safe and effective blood transfusions, here are some key aspects of precautions and monitoring:

Meticulous screening and testing of blood donors

Blood banks must follow screening procedures and protocols to ensure the safety of donated blood. Donors are assessed, including medical history, lifestyle factors, and potential risk factors for infectious diseases. 

Donated blood is also tested for deadly agents like HIV, hepatitis B and C, syphilis, bacterial contamination, and more to reduce the risk of getting infectious diseases through transfusions.

Safety measures during the blood transfusions process

The safety measures and process include identifying the donor blood and recipient to ensure compatibility, proper handling, and storage procedures. Sterile techniques should also be employed while attaching the blood bag to the recipient's vein.

Monitoring vital signs, symptoms, and adverse reactions

Monitoring of blood pressure, heart rate, oxygen saturation, and temperature throughout the transfusion process is essential to reduce the encounter of any adverse reactions or complications. Observation of fever, chills, shortness of breath, chest pain, or other signs of transfusion reactions of the recipient is crucial. Regular monitoring will ensure the identification and management of any potential complications. 

Immediate medical attention in case of complications

It is important to seek prompt medical attention if any complications or adverse reactions occur. Immediate intervention could help mitigate the severity of the complication and ensure the recipient's well-being and avoid trasfusion-related death. 

Meticulous screening of blood donors, adherence to safety protocols during the transfusion process, vigilant monitoring of vital signs and symptoms, and prompt medical attention in case of complications collectively contribute to the successful and safe administration of blood transfusions.

References

• https://www.nhs.uk/conditions/blood-transfusion/
• https://www.britannica.com/science/blood-transfusion
• https://www.cancer.org/cancer/managing-cancer/treatment-types/blood-transfusion-and-donation/how-blood-transfusions-are-done.html
• https://www.blood.gov.au/system/files/documents/companion-21-pbm-guidelines.pdf
• https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/blood-transfusions-in-adults
• https://www.drugs.com/cg/blood-transfusion.html