How much blood is given to patients in the most common surgical operations?

The volume of blood reserved for surgery is affected by the difficulty and scope of the operation. For example, in a bypass operation or hip replacement surgery, patients usually need two to three bags of red cells.

When possible, bleeding is always avoided in surgery. Also, blood is not given nowadays, if it is not really necessary. For this reason, many surgical operations (e.g. appendectomy, endoscopy of the knee) do not require blood transfusion at all.

Sometimes, though, the patient is given ample volumes of blood. For example in a liver transplant operation, tens of litres of blood may be required. Situations such as these are rare, however.​