Engineering perspective on the evolution of push/pull-based dialysis treatments

Abstract

The incidence of kidney disease is rapidly increasing worldwide, and techniques and devices for treating end-stage renal disease (ESRD) patients have been evolving. Better outcomes achieved by convective treatment have encouraged the use of synthetic membranes with high water permeability in clinical setups, and high-flux hemodialysis (HD) and hemodiafiltration (HDF) are now preferred forms of convective therapy in ESRD patients. Push/pull-based dialysis strategies have also been examined to increase convective mass transfer in ESRD patients. The push/pull technique uses the entire membrane as a forward filtration domain for a period of time. However, backfiltration must accompany the forward filtration to compensate for the fluid depletion resulting from the forward filtration, making it necessary to switch the membranes to a backfiltration domain. This paper attempts to describe the advancement of push/pull-based renal supportive treatments in terms of their technical description, hemodialytic efficacy including fluid management accuracy and applicability for clinical use. How the optimization of push and pull actions could translate into better convective efficiency will also be discussed in depth.

Safety and Efficacy of Short Daily Hemodialysis with Physidia S3 System: Clinical Performance Assessment during the Training Period

“…This technical feature is intended to enhance the convective transport phenomenon and can increase the clearance of middle and larger molecular weight substances. Total convective volume obtained from both ultrafiltration as weight loss and forced internal filtration transport ("push-pull" technology) could achieve 4.3 L/session (1.3 weight loss and 3.0 push-pull system), corresponding to 26 L/week, which is in agreement with high-flux HD in ultrafiltration-controlled mode [21,[30][31][32]. Of note, the convective volume given by the machine corresponds to the total volume ultrafiltered (without the weight loss), including the additional ultrafiltration performed via the push-pull-like technique.…”

“…The blood flow pump operates from 100 to 350 mL/min and dialysate flow is set from 150 to 200 mL/min. The balance chamber technology with adjustable ultrafiltration rate is able to provide substantial convective volume-enhancing internal filtration relying on a "push-pull" technology also called SeCoHD for "self-convective hemodialysis" which allows a better removal and a limited membrane fouling [21]. In addition, S 3 has a cartridge set-up, automated prime function, removable tablet with a touch-screen patient interface, and the ability to store and transmit treatment data to the clinic patient file after treatment.…”

“…This holds true for fitting the dialyzer and tubing set, as well as loading dialysate bags and setting the S 3 dialysis monitor via the tablet interface. The total handling time to set the S 3 monitor and launch dialysis session was about 25 (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) minutes, including bag installation, rinsing, and priming phases.…”

Portable, wearable and implantable artificial kidney systems: needs, opportunities and challenges

“…For effective clearance of middle molecules with intermittent use of the WAK, the addition of convection may be required, which is challenging in a closed-loop system with a small dialysate volume. To accomplish such convection, ‘push-pull’ techniques may be used based on alternating transmembrane pressure and half-cycle differences in dialysate volume (created by moving a small volume of liquid back and forth across the dialyser within seconds) 113 . The compact Physidia home dialysis system actively uses ‘push-pull’ technology for ‘self-convective haemodialysis’ 19 .…”