Infectious Complications of Blood Transfusion And Pathology Notes

Blood Transfusion

 

Blood Transfusion Introduction

Blood transfusion is the process of transferring blood/blood products from a donor into the circulating system of the recipient. It is important to properly collect the blood from a donor, prepare its components (if required) store blood/components properly, and transfuse in such a way as to avoid any risks or hazards.

Donor Selection:

Donor selection is based on medical history and a few routine physical examinations (weight, blood pressure, temperature, hemoglobin) are done to know whether the donor is suitable for donating blood.

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• Donors should be healthy. There are three types of donors, namely, voluntary (should be encouraged), replacement, and professional
• It is important to know whether the patient has a history of diseases like hepatitis, AIDS, or syphilis and if so, blood should not be obtained from them.
• In the blood bank, blood is routinely screened for a few common infections.

Anticoagulants used: The different anticoagulants—preservative solutions available are:

• Citrate phosphate dextrose (CPD)
• Citrate phosphate dextrose adenine (CPDA-1)
• Acid citrate dextrose (ACD) is not used nowadays.

Storage of blood: Blood is stored in a refrigerator at 2° to 6 °C.

Predonation check-up:

Donor Blood: The following tests are routinely carried out on the donor’s blood:

• ABO and Rh grouping

Tests for:

• HBsAg, anti-HCV, anti-HIV-1 and HIV-2, and serum alanine amino transferase (ALT)
• Malaria and syphilis.

Recipient Blood: The recipient’s ABO and Rh grouping is also carried out.

Compatibility Testing (Pretransfusion Testing)

• Before the transfusion of any blood or its components, it is essential to know whether they are compatible with the recipient’s blood.
• This is achieved by performing a set of procedures known as compatibility testing.
• Sometimes, the term compatibility test and cross-matching are used interchangeably, but cross-matching is only a part of the compatibility test.

Compatibility tests include:

• Review of patient’s past blood bank history and records (if done earlier)
• ABO and Rh typing of the recipient and donor
• Antibody screening test of recipient’s and donor’s serum
• Cross-matching is very important before any blood transfusion.

Types of cross-match:

Blood Components

• It is possible to separate different components of blood from a single unit of whole blood.
• These components can be used individually to help more than one patient for many purposes.
• Thus, red cells can be transfused to an anemic patient and plasma to a burns patient.
• This also ensures that only the required components are transfused.

Transfusion Reactions

Write a short note on transfusion reactions.

• Blood transfusion is useful and life-saving when performed with caution and with clear indication.
• Sometimes (about 2–4% of cases), unfavorable complications occur despite precaution and preventive measures, which are known as transfusion reactions.
• They may be broadly divided into infectious and non-infectious complications.

Noninfectious Complications

Transfusion reactions may result from immune and nonimmune mechanisms.

Immune-Mediated (Immediate and Delayed) Reactions:

Acute hemolytic transfusion reaction

• ABO incompatibility between recipient and donor, destroying donor cells.
• This is brought out by the naturally occurring (preformed) antibodies, namely, anti-A and
  anti-B (depending on the blood group).
  • Massive intravascular hemolysis: This is one of the serious complications that develop within 1 to 4 hours and with only a few milliliters of incompatible red cells.
  • The preformed IgM antibodies (anti-A and anti-B) in the recipient coat transfused donor red cells and activated the complement system to form a membrane attack complex (C5-9). This results in intravascular destruction (hemolysis) of transfused donor red blood cells.
• Rh’s incompatibility: Because anti-Rh antibodies are not complement-filing, in Rh incompatibility hemolysis develops in the extravascular compartment.

Complications of blood transfusion:

Delayed Hemolytic Transfusion Reaction:

• In the recipient, if antibody titer is too low and weak to be detected during cross-match, it may not cause immediate hemolysis at the time of transfusion.
• Instead, it may lead to a gradual increase in the antibody titer causing delayed, gradual lysis of donor red cells and is known as a delayed hemolytic transfusion reaction.

Febrile Nonhemolytic Reaction:

• The patient develops a fever, chills, rigors, and headache 30 to 60 minutes after transfusion.
• It is due to sensitization to leukocyte antigens.

Allergic Reaction:

• Allergic reaction manifests as urticaria (hives), fever, bronchospasm, and rarely anaphylactic shock.
• It is due to exposure of allergens in the donor’s plasma to IgE antibodies in the recipient’s plasma, which activates mast cells and releases histamine/leukotrienes.

Transfusion Associated Graft Versus Host Disease (TA-GVHD):

• Transfusion-associated GVHD is a rare but potentially fatal complication of blood transfusion.
• This may develop 10 to 12 days after transfusion.

Transfusion-Related Acute Lung Injury (TA RLI):

• It is an uncommon complication of blood transfusion.
• It results from the transfusion of donor plasma containing high levels of anti-HLA antibodies which bind to the HLA of leukocytes of the recipient.
• These leukocytes aggregate in the pulmonary microcirculation and release mediators, causing increased vascular permeability.
• This leads to acute pulmonary edema and signs and symptoms of acute respiratory failure.

Nonimmunological (Immediate and Delayed) Reactions:

• Circulatory Overload:
  • Following a whole blood transfusion, the blood volume and venous pressure also increase.
  • This may be significant in the elderly, pregnant women and those with reduced cardiac function resulting in acute pulmonary edema.
  • This can be avoided using blood components like packed red blood cells.
• Air Embolism:
  • This was common earlier when the transfusion was given from a glass bottle.
  • Presently, due to the use of plastic bags with a closed tubing system, this complication does not develop.
• Iron Overload (Transfusion Sclerosis):
  • This is seen in patients who receive multiple transfusions for a few years
    (for example, Thalassemia).
  • The excess iron gets deposited in reticuloendothelial cells of the spleen, bone marrow, liver, heart, and endocrine glands.
• Thrombophlebitis: Inflammation of the vein may develop in patients with indwelling catheters.

Infectious Complications

Write a short note on infectious complications of blood transfusion.

Transfusion of infected blood may transmit a few diseases like AIDS, hepatitis (HBV, HCV, and HDV), HTLV-I and II, malaria, and cytomegalovirus infection. This is prevented by screening the donors for these common and ominous infections.