Peripheral venous access devices for apheresis: 16-gauge is not always needed.

PVA devices with a size of 16-18G provided the maximum flow admitted by the apheresis system. The 20G provided flow rates for a significant number of procedures, and 22G could be used in some procedures. The hematocrit should be taken into account when selecting the PVA device since, at hematocrit of 25%, the flow can be from 14% to 30% higher than flow rates reached with blood at hematocrit of 45%.