Iatrogenic: Transfusions- Emergency Conditions, Signs, Causes And Differentials

Question 1

What are the most common complications following discharge from an extended stay in intensive care?

Answer 1

Muscle weakness and wasting (total immobility in IC ward)

Nutritional deficiencies

Sleep disorders (pain killer usage and the atmosphere)

Inability to swallow effectively, and microaspiration of food (Parenteral feeding or intubation)

Recurrent chest infections (intubation)

Question 2

What is transfusion related acute lung injury?

Answer 2

Transfusion related acute lung injury (TRALI), is a result of granulocyte activation in the pulmonary vasculature which results in increased vascular permeability.

Occurs after transfusion (within 6 hours), any plasma-containing blood products can cause this.

MOA - activation of patients neutrophils by donor antibodies that target human neutrophil antigen or HLA. This causes endothelial damage and capillary leak causing pulmonary oedema.

Question 3

What are the symptoms/signs of transfusion related acute lung injury (TRALI)?

Answer 3

Dyspnoea

Tachypnoea

Fever

Cyanosis

Hypotension

(Signs of hypoxia respiratory distress)

Bilateral pulmonary crackles

Question 4

What is transfusion association circulatory overload (TACO)?

Answer 4

A clinical syndrome of reduced cardiac output, tissue hypoperfusion, increased pulmonary pressure and tissue congestion.

It is a common differential for transfusion related acute lung injury (TRALI), both cause pulmonary oedema and present similarly.

However elevated BNP, high central venous pressure (raised JVP) or high pulmonary artery wedge pressure indicate it is TACO. (TRALI Only has the lungs affected, TACO affects the entire circulatory system)

Question 5

A patient has major haemorrhage and is given IV fluids to stabilise their haemodynamic system, why are their coagulation results abnormal?

Answer 5

An abnormal coagulation result is an extended PT and/or APTT.

In transfusion, the person is often left with diluted blood (most fluid used isn’t blood products), the dilution of platelets and clotting factors lengthens both APTT and PT.

Question 6

What constitutes a massive transfusion?

Answer 6

Receiving more than 10 units of blood in 24 hours or more than 4 units of blood in 4 hours

Question 7

What are the complications of a massive blood transfusion?

Answer 7

1. Transfusion related acute lung injury (TRALI) - most common cause of death post-transfusion, presents as acute respiratory distress within 6 hours of transfusion
2. Hypocalcemia - due to the citrate preservative in blood products binding calcium
3. Hypothermia (enzyme dysfunction at low temp)
4. Dilutional coagulopathy - factor/platelet depletion
5. Delayed/immediate haemolytic reactions
   - immediate; ABO incompatibility
   - delayed; reactions to minor blood antigens

Question 8

What are the effects of hypothermia on the body?

Answer 8

HYPOCALCEMIA: Reduction in the metabolism of citrate, increasing risk of hypocalcemia (citrate binds calcium)

ACIDOSIS/ARRYTHMIA: Reduction in the metabolism of lactate, increasing risk of metabolic acidosis and cardiac arrythmias

ISCHEMIA: Shifting the oxyhemoglobin dissociation curve, reducing tissue perfusion

Question 9

Why is hypocalcemia a risk in blood transfusion?

Answer 9

The blood products (especially FFP and plasma) contain a lot of citrate, this binds calcium and causes hypocalcemia.

Presentation:
Parasthesia
Muscle cramps or spasms
Seizures 
Cognitive impairment