Fat removal during cell salvage: an optimized program for a discontinuous autotransfusion device
The study was funded by the Department of Anesthesiology, University Hospital of Regensburg. Sorin Group Italia (Mirandola, Italy) provided materials such as an autotransfusion device XTRA with the modified program “Pfat,” autotransfusion sets, and technical support.
Abstract
BACKGROUND
Fat in wound blood observed in orthopedic or cardiac surgery might pose a risk for fat embolism during blood salvage. Fat removal was optimized in the washing process.
STUDY DESIGN AND METHODS
In an experimental study blood from fresh donations was adjusted to a hematocrit (Hct) of 25% and an admixture of 1.25% human tissue fat. This blood was processed with the cell salvage device XTRA in a modified program mode. Volumetric quantification of fat was performed after centrifugation of blood samples in Pasteur pipettes. From the volumes, the Hct levels and the concentrations of fat and other variables elimination rates and RBC recovery were calculated.
RESULTS
Pretests showed wash volume, wash flow, and process interruptions affecting fat elimination. With the new optimized fat elimination program Pfat removal rate of fat increased to 98.5 ± 0.9% for the 225-mL bowl. The product had a mean Hct of 48.7 ± 1.2% and a RBC recovery rate of 93.5 ± 2.3%. The program conserved the high elimination rates for albumin, heparin, potassium, and free plasma hemoglobin (98.8, 99.3, 95.3, and 94.9%, respectively). Similar high fat removal was also observed with bowls of smaller size, namely, 98.1% for the 175-mL bowl and 98.2% for the 125- and the 55-mL bowls. With test blood of Hct 10% a mean fat elimination of 99.6 ± 01% was observed.
CONCLUSIONS
A special program modification Pfat involving extra washing and RBC concentration steps significantly improves fat removal by the Latham bowl–based autotransfusion device XTRA, thus yielding results equivalent to the continuous cell salvage system.
