Red blood cell salvage analysis from clotted blood.

BACKGROUND: Blood clots discovered within body cavities intra-operatively are often manually broken up and placed in an autotransfusion device to recover autologous blood cells. This study evaluated the efficiency at which these red blood cells can be recovered from clot and to determine if these cells would be free of fibrin and clumping which might pose a risk of micro-emboli.

MATERIALS AND METHODS: Whole blood was aliquoted into 25 mL volume samples. The blood was then allowed to clot, and after 24 hours the clotted blood was manually kneaded by hand for 1, 2, 3, or 5 minutes. One mL of the harvested blood was fixed and processed for scanning electron microscope imaging. Plasma from the rest of the sample was then separated and underwent spectrophotometry for analysis of relative free haemoglobin.

RESULTS: Blood recovered from the clotted blood ranged from 60 to 80% as time increased from 1 to 5 minutes of kneading. Volume of erythrocytes recovered from 1 minute compared to 2 minutes was statistically significant but not significant between 2 minutes or any longer period of time. Imaging did not show any evidence of fibrin strands or significant cell fragmentation. Spectrophotometry showed a steady increase of observed absorption at 540 nm, indicative of free haemoglobin, as manual kneading time increased.

DISCUSSION: Red blood cells were able to be efficiently recovered from clotted blood. Imaging studies did not show any evidence of red blood cells trapped within fibrin mesh.