Blood flow distribution in sorbent beds: analysis of a new sorbent device for hemoperfusion

A new polymer-based sorbent cartridge has been recently developed for enhan cing middle molecule removal during hemodialysis. The cartridge (Betasorb(R ), Renaltech, New York, USA) has been designed to be placed in series with the dialyzer in the blood circuit. It is therefore important to evaluate th e distribution of flow into the blood compartment of the device in order to assess if the surface of the sorbent is utilized to the best for this purp ose, a special imaging technique was utilized. Cartridges were analyzed dur ing a simulated in vitro circulation at 250 and 350 ml/min of blood flow an d 25% and 40% hematocrit. Cartridges were placed in vertical position and a cross longitudinal section 1 cm thick was analyzed in sequence by a helica l scanner. Dye was injected into the arterial inlet and the progressive dis tribution was evaluated by sequential densitometrical measures carried out automatically by the machine. The sequential images analyzed by the scanner demonstrated excellent distribution of the flow in the blood compartment w ith minimal difference between the central and the peripheral regions of th e compartment. In particular the following flow velocity pattern could be o bserved under the different experimental conditions tested [GRAPHICS] We may conclude that the cartridge design is adequate and no channelling ef fects could be detected in the blood compartment. The flow distribution is slightly affected by changes in flow rate and hematocrit showing an optimal utilization of the available surface for molecule adsorption.