MOTIVATION FOR INTRA-OPERATIVE BLOOD SALVAGE

Current risks and poorly defined benefits will continue to be problems associated with blood transfusions. Infectious complications, immunological events, and a suggestion of increased mortality all pose as a threat to transfusion recipients, along with blood shortages and the rising cost of blood incurred by the increasingly advanced hemovigilance techniques.

The mechanisms leading to the largely unfavourable outcomes of transfusion therapy remain unclear. Current thinking points to several possibilities, including the effects of storage lesions in stored red blood cells (RBC’s), the long-term persistence of donor leukocytes in the recipient circulation, or a combination of both. Whatever the cause of transfusion-related complications, the increasingly unfavourable safety profile with transfused blood has led to a global movement to minimize the inappropriate use of allogeneic blood and blood products. Although the quest for “blood substitutes: is ongoing, none have attained clinical significance. In the meantime, employing blood conservation techniques is no longer an option but a vital necessity.

Intra-operative blood salvage with intra-operative auto-transfusion is an important and commonly used blood conservation technique in spinal surgery.

With this technique, blood lost during surgery is recuperated and processed through a pump system (Cell Saver) then transfused back to the patient. In this case it is scavenged blood that returns to the patient. It does not contain platelets or coagulation factors. This requires a system that suctions the wound, separates the RBC’s from the other blood products and debris, washes the RBC’s, and returns them to the patient. It is estimated that about half of the lost red blood cells can be salvaged (1).

The main complication is that a dilutional or disseminated coagulopathy can occur, and there is also a question about the complete elimination of tissue residues. Cell saving is therefore contraindicated in the presence of coagulopathies. Other rare complications include pulmonary injuries probably linked to leukoagglutinins (2) and transient hemoglobinuria (1).

The technique has been reported to be effective in spine surgery (3, 4, 5). In a meta-analysis, Huet et al. (6) concluded that cell salvage in orthopaedic surgery decreases the frequency of allogeneic transfusions, and a recent Cochrane review on cell salvage the poor methodological quality of most studies (7).

References:

1. Flynn JC, Metzger CT, Csencsitz TA (1982) Intraoperative autotransfusion (IAT) in spinal surgery. Spine 7:432-435.
2. Walker R (1987) Special report: transfusion risks. AM J Clin Pathol 88:374-378.
3. Behrman MJ, Keim HA (1992) Perioperative red blood cell salvage in spine surgery. A prospective analysis. Clin Orthop 278:51-57.
4. Lennon RK, Hosking MP, Gray JR, Klassen RA, Popovsky MA, Warner MA (1987). The effects of intraoperative blood salvage and induced hypotension on transfusion requirements during spinal surgical procedures. Mayo Clin Proc 62:1090-1094.
5. Mandel RT, Brown MD, McCollough NC 3rd, Pallares V, Varlotta R (1981).
Hypotensive anaesthesia and autotransfusion in spinal surgery Clin Orthop 154:27-33.
6. Huet C, Salmi LR, Ferguson D, Koopman-van Gemert AW, Rubens F, Laupacis A (1999) A meta-analysis of the effectiveness of cell salvage to minimize perioperative allogeneic blood transfusion in cardiac and orthopaedic surgery. International Study of Perioperative Transfusion (ISPOT) Investigators. Anesth Analg 89:861-869.
7. Carless PA, Henry DA, Moxey AJ, O’Connell DL, Ferguson DA (2004) Cell salvage for minimising perioperative allogeneic blood transfusion. IN: The Cochrane Library Issue 1. Wiley, London

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