An extracorporeal carbon dioxide removal (ECCO2R) device operating at hemodialysis blood flow rates

R Garrett Jeffries,Laura Lund,William J Federspiel,Brian Frankowski

doi:10.1186/s40635-017-0154-1

Abstract

BackgroundExtracorporeal carbon dioxide removal (ECCO2R) systems have gained clinical appeal as supplemental therapy in the treatment of acute and chronic respiratory injuries with low tidal volume or non-invasive ventilation. We have developed an ultra-low-flow ECCO2R device (ULFED) capable of operating at blood flows comparable to renal hemodialysis (250 mL/min). Comparable operating conditions allow use of minimally invasive dialysis cannulation strategies with potential for direct integration to existing dialysis circuitry.MethodsA carbon dioxide (CO2) removal device was fabricated with rotating impellers inside an annular hollow fiber membrane bundle to disrupt blood flow patterns and enhance gas exchange. In vitro gas exchange and hemolysis testing was conducted at hemodialysis blood flows (250 mL/min).ResultsIn vitro carbon dioxide removal rates up to 75 mL/min were achieved in blood at normocapnia (pCO2 = 45 mmHg). In vitro hemolysis (including cannula and blood pump) was comparable to a Medtronic Minimax oxygenator control loop using a time-of-therapy normalized index of hemolysis (0.19 ± 0.04 g/100 min versus 0.12 ± 0.01 g/100 min, p = 0.169).ConclusionsIn vitro performance suggests a new ultra-low-flow extracorporeal CO2 removal device could be utilized for safe and effective CO2 removal at hemodialysis flow rates using simplified and minimally invasive connection strategies.

Highlights

Extracorporeal carbon dioxide removal (ECCO2R) systems have gained clinical appeal as supplemental therapy in the treatment of acute and chronic respiratory injuries with low tidal volume or non-invasive ventilation
CO2 is predominantly carried in the form of highly soluble bicarbonate ion that rapidly restores depleting CO2 as it is eliminated, and the CO2 dissociation curve is essentially linear and does not saturate like the oxyhemoglobin dissociation curve [8,9,10]. These differences provide the opportunity to augment CO2 removal efficiency with gas exchanger design features aimed at reducing the thickness of the diffusive boundary layer at the gas exchange surface, where gas transport through blood is limited to diffusion [11]
This paper reports on the design and bench testing of an ultra-low-flow ECCO2R device (ULFED) utilizing the rotating impeller concept

Summary

Introduction

Extracorporeal carbon dioxide removal (ECCO2R) systems have gained clinical appeal as supplemental therapy in the treatment of acute and chronic respiratory injuries with low tidal volume or non-invasive ventilation. ECMO performs the function of blood oxygenation and carbon dioxide (CO2) removal independently of the lungs, allowing injured tissue to rest and heal [2]. CO2 is predominantly carried in the form of highly soluble bicarbonate ion that rapidly restores depleting CO2 as it is eliminated, and the CO2 dissociation curve is essentially linear and does not saturate like the oxyhemoglobin dissociation curve [8,9,10] These differences provide the opportunity to augment CO2 removal efficiency with gas exchanger design features aimed at reducing the thickness of the diffusive boundary layer at the gas exchange surface, where gas transport through blood is limited to diffusion [11]

Methods

Results

Discussion

Conclusion