The acu-men™: A new device for continuous renal replacement therapy in acute renal failure

Manns, Markus; Polaschegg, Hans D.; Schlaeper, Christian; Steinbach, Bernd; Evering, H G

doi:10.1046/j.1523-1755.1998.00959.x

Cited by 4 publications

(4 citation statements)

References 18 publications

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“…The push-pull of pulsatile flow has been shown to increase convective mass transfer across the dialyzer membrane, a desirable attribute (20 -23). Previously, the acu-men® hemofiltration device utilized a pulsatile blood pump in a much larger collapsible chamber (24). The Pulsar pump propels blood by pulsatile flow (25), but there is no dialysis device currently used that implements such a mechanism for both blood and dialysate movement.…”

Section: Discussionmentioning

confidence: 99%

Technical Breakthroughs in the Wearable Artificial Kidney (WAK)

Gura¹,

Macy²,

Beizai³

et al. 2009

Clinical Journal of the American Society of Nephrology

107

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Background: The wearable artificial kidney (WAK) has been a holy grail in kidney failure for decades. Described herein are the breakthroughs that made possible the creation of the WAK V1.0 and its advanced versions V 1.1 and 1.2.Design: The battery-powered WAK pump has a double channel pulsatile counter phase flow. This study clarifies the role of pulsatile blood and dialysate flow, a high-flux membrane with a larger surface area, and the optimization of the dialysate pH. Flows and clearances from the WAK pump were compared with conventional pumps and with gravity steady flow.Results: Raising dialysate pH to 7.4 increased adsorption of ammonia. Clearances were higher with pulsatile flow as compared with steady flow. The light WAK pump, geometrically suitable for wearability, delivered the same clearances as larger and heavier pumps that cannot be battery operated. Beta 2 microglobulin (␤ 2 M) was removed from human blood in vitro. Activated charcoal adsorbed most ␤ 2 M in the dialysate. The WAK V1.0 delivered an effective creatinine clearance of 18.5 ؎ 3.2 ml/min and the WAK V1.1 27.0 ؎ 4.0 ml/min in uremic pigs.Conclusions: Half-cycle differences between blood and dialysate, alternating transmembrane pressures (TMP), higher amplitude pulsations, and a push-pull flow increased convective transport. This creates a yet undescribed type of hemodiafiltration. Further improvements were achieved with a larger surface area high-flux dialyzer and a higher dialysate pH. The data suggest that the WAK might be an efficient way of providing daily dialysis and optimizing end stage renal disease (ESRD) treatment.

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Section: Discussionmentioning

confidence: 99%

Technical Breakthroughs in the Wearable Artificial Kidney (WAK)

Gura¹,

Macy²,

Beizai³

et al. 2009

Clinical Journal of the American Society of Nephrology

107

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“…16 The filtrate is extracted in method (a) either using height adjustment of the collecting bag or via a separate IV pump. This method is not typically favored in pediatric CRRT realm due to the slow nature of the process.…”

Section: Discussionmentioning

confidence: 99%

“…Volumetric balancing has been described previously 16 by enclosing the UF and RF within the same larger compartment separated by an impermeable flexible membrane. UF and RF movement was driven by inertia in the pulsatile blood flow, gravitational head, and membrane tension.…”

Section: Discussionmentioning

confidence: 99%

“…Concern also exists against using independent UF and RF pumps or two electrically linked pumps for FB to avoid excessive patient overload/dehydration, should one of the pumps fail. 16,21,22 Our mechanically coupled FB design gives highest priority to patient safety, followed by accuracy. A novel benefit of our device is the multi-stage approach to ensure perfect fluid balance under varying physiological pressure conditions, through the simultaneous use of mechanically coupled UF and RF pumps and flow control implementation via variable valve timing.…”

Section: Discussionmentioning

confidence: 99%

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Development of an Accurate Fluid Management System for a Pediatric Continuous Renal Replacement Therapy Device

et al. 2013

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Acute kidney injury is common in critically ill children and renal replacement therapies provide a life saving therapy to a subset of these children. However, there is no Food and Drug Administration approved device to provide pediatric continuous renal replacement therapy (CRRT). Consequently, clinicians adapt approved adult CRRT devices for use in children due to lack of safer alternatives. Complications occur using adult CRRT devices in children due to inaccurate fluid balance (FB) between the volumes of ultrafiltrate (UF) removed and replacement fluid (RF) delivered. We demonstrate the design and validation of a pediatric fluid management system for obtaining accurate instantaneous and cumulative FB. Fluid transport was achieved via multiple novel pulsatile diaphragm pumps. The conservation of volume principle leveraging the physical property of fluid incompressibility along with mechanical coupling via a crankshaft was used for FB. Accuracy testing was conducted in vitro for 8-hour long continuous operation of the coupled UF and RF pumps. The mean cumulative FB error was <1% across filtration flows from 300 mL/hour to 3000 mL/hour. This approach of FB control in a pediatric specific CRRT device would represent a significant accuracy improvement over currently used clinical implementations.

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