Single Lumen Alternating Micro-Batch Hemodiafiltration (SLAMB-HDF): A Device for Minimally Invasive Renal Replacement Therapy

Abstract

Blood-based RRT, such as hemodialysis, requires access to the bloodstream and adequate blood flow to enable the requisite clearance. As such, nearly all RRT systems require two lumens, enabling a blood circuit that pulls blood from one lumen or needle and returns it via another lumen or needle. The proposed single lumen alternating micro-batch (SLAMB) technique uses a small single lumen to draw a "micro" batch of blood into a single reservoir. In the reservoir, the "batch" of blood is circulated at a high blood flow rate through a hemofilter or hemodialyzer, enabling efficient small- and middle-molecule clearance. Thereafter, the "purified" blood is returned to the patient and the cycle is repeated. Each batch comprises 20-300 ml of blood, which is adjusted to the vascular access, hemodynamic status, and size of the patient. Up to 15 cycles can be done per hour, allowing this system to achieve a blood clearance level comparable to modern continuous RRT systems. Because the system can function with a small-bore single lumen, this device can work with existing central lines, thus allowing for less invasive vascular access. Because of their size and relative simplicity, SLAMB-based systems are less expensive, smaller, and have improved portability. Lastly, a similar, manual SLAMB-hemofiltration kit, which requires no electricity or battery, can be developed at low cost (<$25) for use in austere medical conditions, thus expanding the availability of RRT for patients with AKI.