Massive blood transfusion

Massive transfusion defined as replacement of >1 blood volume (5L) in less than 24h. Haemostatic failure may result from dilution or consumption of coagulation factors and platelets, DIC, systemic fibrinolysis or acquired platelet dysfunction.

Pathophysiology

• Dilution/consumption e.g. replacement of intravascular volume with fluids lacking coagulation factors or platelets e.g. packed red cells and crystalloids.

• DIC may follow tissue damage, hypoxia, acidosis, sepsis or haemolytic transfusion reaction. Causes coagulopathy due to consumption of platelets and coagulation factors, fibrinolysis and circulating fibrin degradation products (see p512).

• Systemic fibrinolysis particularly associated with liver disease; causes rapid lysis of thrombi at surgical sites and plasmin-induced fibrinogenol-ysis; may be assessed by the euglobulin lysis time.

• Platelet dysfunction may be due to circulating FDPs, exhausted platelets activated by intravascular trauma or effects of transfusion of stored platelets.

Investigations

• Baseline tests

- Haematocrit.

- Platelet count.

- Fibrinogen.

524 • Frequent reassessment of tests to monitor effect of, and need for, further replacement therapy.

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