Abstract
BackgroundCritically ill patients with acute respiratory distress syndrome and acute exacerbations of chronic obstructive pulmonary disease often develop hypercapnia and require mechanical ventilation. Extracorporeal carbon dioxide removal can manage hypercarbia by removing carbon dioxide directly from the bloodstream. Respiratory hemodialysis uses traditional hemodialysis to remove CO2 from the blood, mainly as bicarbonate. In this study, Stewart’s approach to acid-base chemistry was used to create a dialysate that would maintain blood pH while removing CO2 as well as determine the blood and dialysate flow rates necessary to remove clinically relevant CO2 volumes.MethodsBench studies were performed using a scaled down respiratory hemodialyzer in bovine or porcine blood. The scaling factor for the bench top experiments was 22.5. In vitro dialysate flow rates ranged from 2.2 to 24 mL/min (49.5–540 mL/min scaled up) and blood flow rates were set at 11 and 18.7 mL/min (248–421 mL/min scaled up). Blood inlet CO2 concentrations were set at 50 and 100 mmHg.ResultsResults are reported as scaled up values. The CO2 removal rate was highest at intermittent hemodialysis blood and dialysate flow rates. At an inlet pCO2 of 50 mmHg, the CO2 removal rate increased from 62.6 ± 4.8 to 77.7 ± 3 mL/min when the blood flow rate increased from 248 to 421 mL/min. At an inlet pCO2 of 100 mmHg, the device was able to remove up to 117.8 ± 3.8 mL/min of CO2. None of the test conditions caused the blood pH to decrease, and increases were ≤0.08.ConclusionsWhen the bench top data is scaled up, the system removes a therapeutic amount of CO2 standard intermittent hemodialysis flow rates. The zero bicarbonate dialysate did not cause acidosis in the post-dialyzer blood. These results demonstrate that, with further development, respiratory hemodialysis can be a minimally invasive extracorporeal carbon dioxide removal treatment option.
Highlights
Ill patients with acute respiratory distress syndrome and acute exacerbations of chronic obstructive pulmonary disease often develop hypercapnia and require mechanical ventilation
We explore whether extracorporeal CO2 removal (ECCO2R), in the form of respiratory hemodialysis, is feasible without decreasing blood pH using a custom dialysate developed using Stewart’s model
Carbon dioxide (CO2) removal rates measured from respiratory dialysis are shown in Fig. 2 are presented, by a dual axis, in terms of actual and scaled up CO2 removal rates
Summary
Ill patients with acute respiratory distress syndrome and acute exacerbations of chronic obstructive pulmonary disease often develop hypercapnia and require mechanical ventilation. Ventilating patients with acute respiratory distress syndrome (ARDS) can cause additional lung damage [1]. An ARDS Network clinical trial demonstrated LPV reduced mortality by 8.8% [2], more recent studies have shown that these settings may still cause ventilator-induced lung injury (VILI) [3, 4]. Several studies have demonstrated the safety and feasibility of ultra-protective lung ventilation when used in conjunction with an extracorporeal CO2 removal (ECCO2R) device [5, 6]. In addition to ARDS, chronic obstructive pulmonary disease (COPD) patients frequently develop hypercapnia during acute exacerbations. When combined with the ARDS population, there is a significant unmet need for a simple, minimally invasive therapy to remove CO2
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
