Bedside Washing of Stored Red Blood Cells: A Simple Apparatus Based on Microscale Sedimentation in Normal Gravity

The aim of this study was to develop and evaluate a simple, inexpensive bedside RBC washer with the capability to process multiple pRBC units within a short period without any alteration to current blood collection and storage practices. Washing pRBC units prior to transfusion is recommended for hypersensitive patients who have a higher susceptibility towards Allergic Transfusion Reactions (ATR) due to residual plasma proteins. Unfortunately, conventional washing is bulky, expensive and laborious, due to concentrating washed units through centrifugation. In response, we developed a bedside RBC washer that utilizes gravitational sedimentation of RBCs within a saline suspension. We evaluated its ability to concentrate washed pRBC units to a therapeutic hematocrit of 65%, but it optimally concentrated to a physiological hematocrit of 41%. Concentration was found to be dependent on initial morphology of the unit. In terms of improved quality, the gravity-driven washing system performed comparably with conventional washing.