Extra Topic 3.2 -- Blood Transfusion

Question 1

Type and cross-matched blood is not yet available.

What will you transfuse?

Answer 1

If typed and cross-matched blood products were not available and urgent transfusion was needed,

I would transfuse type-O Rh-negative pRBCs and change to type specific pRBC’s when they became available.

Contrary to previous thought, many transfusion specialists consider it safe to convert to type specific blood even when the patient has received 10 or more units of type-O pRBCs.

• The concern is that the administration of large amounts of type-O blood may result in an accumulation of anti-A and anti-B antibodies leading to an incompatibility reaction when the patient’s own blood type is subsequently administered.
• However, this concern is probably more justified following the use of whole type-O blood, which contains a significant amount of plasma, rather than pRBCs, which contain only a very minimal amount of plasma.

Question 2

What is the difference between type & screened blood and type & cross-matched blood?

Answer 2

Type and screened blood mixes recipient plasma with a panel of commercial RBCs to detect the presence of various known antibodies, and carries the advantage of identifying rare antibodies.

Type and cross-matching takes it a step further, and mixes the recipient plasma with donor RBCs to detect incompatibility with a specific unit to be administered.

The risk of hemolytic reaction is 2/1000 for type-specific blood, 6/10,000 for type and screened blood, and 5/10,000 for type and cross-matched blood.

Question 3

Fifteen minutes after you start transfusing the patient with type specific pRBCs, the patient develops hypotension, tachycardia, and hematuria.

What do you think is happening?

Answer 3

The occurrence of hematuria, hypotension, and tachycardia shortly after the administration of non-screened or non-crossmatched blood is consistent with

a hemolytic transfusion reaction,

which is often difficult to detect in patients under general anesthesia.

Given this possibility, I would –

• stop the transfusion,
• treat hypotension with fluids and vasopressors,
• recheck the unit number and patient ID, and
• obtain appropriate lab work to confirm a hemolytic reaction.

I would then consider administering mannitol, furosemide, and NaHCO3 to preven renal injury.

Question 4

What is the cause of hemolytic transfusion reactions?

Answer 4

Hemolytic transfusion reactions are most often due to –

ABO incompatibility secondary to clerical error, and usually result from the binding of anti-A or anti-B IgM antibodies to RBC membranes, causing complement mediated hemolysis.

Other, less common causes of intravascular hemolysis include –

mismatched liver, kidney, or bone marrow transplantations, and incompatible platelets containing anti-A antibodies.