College Answer

Massive transfusion (eg. replacement of more than 50% of blood volume in 12 to 24 hours, or  one  circulation blood volume in  24 hrs  [T Oh]) is  associated with  many potential problems which are related to a number of factors including the volume of resuscitation, factors related to the storage blood, and many other related issues. Problems include:

•    Volume  overload  (careful  monitoring  of  filling  pressure,  response  to  volume, diuresis)

•    Over-transfusion (monitor Hb regularly, titrate according to needs)

•    Hypothermia (use of fluid warmers and general measures to minimise heat loss)

•    Dilutional coagulopathy of both clotting factors and platelets (regular and early monitoring of coagulation, and involvement of haematology for replacement therapy [better than according to protocol])

•    Transfusion related lung injury (consider use of filters, leukodepletion)

•    Excessive citrate causing metabolic alkalosis and hypocalcemia (monitor pH and ionised calcium, replace calcium as necessary)

•    Hyperkalaemia (use of “younger” blood, monitor regularly, may require specific therapy)

•    Disease transmission (use of  products on  as  needed basis  only,  standard blood banking precautions)

•    Distractions resulting in not controlling source of haemorrhage, and risks of hurried cross-checking and incompatibility (allocation of sufficient resources and personnel, standard programs in place to facilitate process and anticipate needs)

•    Other problems include loss of identity (cross matching issues, loss of baseline haematological information etc.)

Discussion

Massive transfusion is discussed in greater detail elsewhere. Several definitions exist, but the replacement of 1 blood volume is a popular one.

In fact, and excellent article from Chest (2010) has a nice table (Table 1) of complications from massive transfusion. That table was a strong (dominating) influence on the following list of complications:

Acute complications

• Acute hemolytic transfusion reactions
• Febrile nonhemolytic transfusion reactions
• Tranfusion-associated lung injury (TRALI)
• Transfusion-associated circulatory overload (TACO)
• Allergic reactions to blood products
• Bacterial sepsis due to contaminated blood products
• Hypocalcemia due to citrate
• Hyperkalemia due to high PRBC K⁺ content
• Acidosis due to high PRBC lactate content
• Hypothermia due to use of recently refrigerated PRBCs
• Dilutional coagulopathy due to inappropriate blood product replacement proportions
• Dilutional thrombocytopenia due to lack of platelet replacement

Delayed complications

• Delayed hemolytic transfusion reactions
• Transfusion-related immune modulation (TRIM)  
• Microchimerism - the persistence of an allogeneic cell population of leucocytes
• Transfusion-transmitted diseases, eg. HIV, Hep C
• Posttransfusion graft-vs-host disease (due to non-leukodepleted PRBCs)
• Posttransfusion purpura

The college allso asks the candidate to "outline your management for each".

This requires a large table. The Australian Red Cross Blood Service have a nice table for management steps of transfusion reactions.