The volume of returned red blood cells in a large blood salvage program: where does it all go?

Intraoperative blood salvage is the process whereby shed red blood cells (RBCs) are collected and returned to the patient. We analyzed the trends in the volume of returned RBCs by our blood salvage program across a 12-hospital regional health care system over a 5-year period.

All quality control, RBC recovery, and patient demographic data relating to blood salvage are stored in a large database covering these 12 hospitals. Cases in which blood salvage was performed over a 5-year period were stratified based on patient demographics, hospital, type of surgery, and volume of RBCs recovered.

There were 19,867 surgeries performed during the study period in which blood salvage was used. The median volume of blood returned to each patient was 405 mL (25th-75th percentile, 135-750 mL). Defining the volume of an RBC unit as 200 mL, this represented a median of 1.1 RBC unit equivalents (25th-75th percentile, 0.37-2.1 units) returned to each patient. For the majority of patients, not more than 1 RBC unit equivalent was recovered. Overall, the ratio of cases where at least 1 RBC unit equivalent was recovered to cases where less than 1 RBC equivalent was recovered was 2.5:1; this ratio varied considerably between surgical procedures.

Although overall the mean volumes of RBCs returned to the patients by intraoperative blood salvage were high, the actual volumes returned depended on the case mix. There appears to be an opportunity to use blood salvage more selectively to improve efficiency.