Patient Blood Management Guidelines: Module 1

Critical Bleeding Massive Transfusion

| Background |

3.1 Definitions

3.1.2 Massive transfusion

Massive transfusion has been defined based on the volume of blood loss or on the volume transfused. The most widely used definition proposes the loss or transfusion of one blood volume (about 7% of body weight in adults) over 24 hours;11-14 or approximately 10 units of red blood cells (RBCs). Alternative, ‘real time’ definitions include replacement of half a blood volume within 4 hours,15,16 or blood loss of more than 150 mL per minute.13

The different definitions reflect the diverse clinical scenarios in which critical bleeding occurs. Ultimately, the importance of defining critical bleeding or massive transfusion is to facilitate early recognition of this condition, or its potential, so that appropriate management can be instituted.

In adults, ‘massive transfusion’ may be defined as a transfusion of half of one blood volume in 4 hours, or more than one blood volume in 24 hours (adult blood volume is approximately 70 mL/kg).