RED-BLOOD-CELL DEFORMABILITY IN SEPSIS

The microcirculatory disturbances in sepsis have prompted micropore bu lk-filtration studies of red blood cell (RBC) mechanical behavior (i.e ., deformability). However, these prior reports may not solely reflect RBC behavior because of possible white blood cell (WBC) occlusion of the filter pores. The present study was designed to examine RBC mechan ical alterations in human and experimental sepsis using techniques tha t are not affected by WBC artifacts. RBC were obtained from adult pati ents with sepsis and from healthy control donors. RBC were also obtain ed from Swiss-albino rats in which experimental sepsis was induced via cecal ligation-puncture. Red cell mechanical behavior was tested usin g a computerized micropore filtration system (CTA) and a laser-diffrac tion shearing device (LORCA); the latter provides the extent of RBC de formation at various stresses and the time constant for RBC shape reco very. Salient findings include: (1) for human RBC, significantly decre ased deformability at fluid shear stresses < 5 Pa (LORCA) yet no diffe rences from control with the CTA; (2) for rat RBC in experimental seps is, significant decreases of deformability and shape-recovery time con stant (LORCA) but no differences with the CTA. We conclude that RBC de formability is reduced in sepsis but that micropore bulk-filtration me thods may not be appropriate for detecting these changes.