The major complications of transfusion of blood are the following:
1. Transfusion Reactions :
These reactions may be allergic or haemolytic:
- Haemolytic Reactions
These are again divided in to Delayed Hemolytic reactions and Acute Hemolytic reactions.
- Allergic Reactions
These are usually mild, manifesting as urticaria and are mainly due to plasma proteins.
Treatment: Antihistamines (Avil) + Steroid.
At times (1 in 1.5 lacs) these reactions may be anaphylactic.
Treatment
• Immediately stop the transfusion.
• Adrenaline and steroids.
2. Febrile Reactions
Incidence is I to 3%. These are due to infusion of white cell microaggregates. The incidence of these reactions can be minimized by the use of microfilter blood sets with pore size of 20 to 40 microm instead of conventional blood sets with pore size of 170 microm which permits the infusion of WBC microaggregates. These febrile reactions are mild and generally require no treatment.
3. Infectious Complications of Transfusion
Chances of infectious Complications of Transfusion are more with pooled products (derived from large number of donors) like cryoprecipitate.
- Hepatitis
Incidence is 1 in 3,000.
90% of these are due to non A non B (hepatitis C) virus.
- Acquired Immunodeficiency Disease (AIDS)
Incidence is I in 60,000 to 1 in 2 lacs. It is because of HIV-1.
Other Viral Diseases
- Cytomegalovirus can produce severe infection in immunocompromised patients.
- Epstein Barr virus.
- Human T cell lymphotrophic virus (HTLV-1 and 2).
- Parvovirus.
Bacterial Infections
- Pseudomonas
- Staphylococcus
- Syphilis
- Brucellosis
- Salmonella
- Yersinia
- Rickettsial diseases
Parasite
- Malaria: Malarial parasite may survive for 3 weeks in stored blood.
- Toxoplasma.
- Filariasis.
- Trypanosomiasis.
4. Fluid Overloading and Pulmonary Edema
In cardiac compromised individuals the Complications of Transfusion of blood are mainly in the form of fluid overload that can even result in heart failure.
.5. Metabolic Complications of Transfusion
Metabolic complications are more prominent in massive transfusion. The metabolic Complications of Transfusion of blood are:
1. Hyperkalemia: Stored blood has high potassium levels.
2. Hypocalcemia: Citrate chelates calcium. Hypocalcemia only occurs if rate of infusion is very high (1 unit in less than 5 minute).
The indications for calcium replacement during transfusion are:
- Blood given at a very fast rate.
- Liver diseases (because citrate is metabolised by liver).
- Massive blood transfusion.
- Severe hypothermia (decreases citrate metabolism).
3. Acid base abnormalities: Blood gases shows variable results. Acidic pH of stored blood causes acidosis while citrate metabolism causes alkalosis. In massive transfusion alkalosis is more common due to citrate intoxication (one molecule of citrate generates 3 molecules of bicarbonate).
6. Coagulation Complications of Transfusion
Massive blood transfusion causes dilutional coagulopathies especially dilutional thrombocytopenia (stored blood has no platelets and concentration of other clotting factors is also very less).
Treatment
- Fresh blood.
- Fresh frozen plasma.
- Specific blood component therapy.
- Platelets.
7. Hypothermia
Blood should be warmed to 37°C before infusion.
8. Immunosuppression
Graft versus host reaction.
9. Tissue hypoxia
2,3 DPG in stored blood can shift oxygen dissociation curve to left.
10. Endotoxemia and Septicemia
Can occur if blood is contaminated with bacterial growth and contamination is most commonly due to Pseudomonas (as it can grow at 4°C) but can also with staphylococcus, Yersinia and citrobacter.
11. Adult Respiratory Distress Syndrome (ARDS)
Respiratory Complications of Transfusion are deadly. In particular is TRALI or Transfusion realed acute lung injury. ARDS has very high mortality and causes of ARDS after transfusion may be:
- Mismatched transfusion reaction.
- Anaphylactic reaction.
- Pulmonary vasculature obstruction by micro- aggregates (very rare).
12. Disseminated Intravascular Coagulation (DIC)
Causes of Coagulative Complications of Transfusion may be:
- Mismatched transfusion reaction.
- Dilutional coagulopathies leading to activation of coagulation system.