Microaggregate content and flow rates of packed red blood cells

Platelet rich red cells (PRRC) and platelet poor red cells (PPRC) are both prepared in the course of red cell production. PRRC tend to have a higher hematocrit (82 +/- 7) than PPRC (77 +/- 5), (p less than .001). There are more microaggregates present in PRRC (2.48 +/- 1.41 gm) than in PPRC (1.46 +/- 0.61 gm), (p less than .001). The infusion rate for PRRC was 4.0 X 1.8 ml/minute, and this was significantly smaller than for PPRC which was 9.7 +/- 1.7 m/minute, (p less than .001). This compares to a rate for whole blood of 32.8 ml/minute. The difference in flow rate of the two types of red blood cells is in part due to a difference in viscosity, but more inportantly due to a difference in microaggregate content. Flow rate is normalized for both types of packed cells by the addition of 100 to 150 ml of saline, while infusion time is normalized by the addition of only 50 to 100 ml of saline to the packed cell units.