Bench Validation of a Compact Low-Flow CO2 Removal Device

May, Alexandra; Jeffries, R. Garrett; Frankowski, Brian J.; Burgreen, Greg W.; Federspiel, William J.

doi:10.1186/s40635-018-0200-7

Cited by 16 publications

(28 citation statements)

References 32 publications

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“…Low HCT resulting from a shoulder hematoma (animal 3), pulmonary embolism (animal 4), and subcutaneous bleeding (animal 5) resulted in slightly diminished CO 2 removal rates [24,25] and increased blood flow rates during the latter half of the study. The in vivo CO 2 removal performance on POD 7 was within ALT alanine transferase, ALP alkaline phosphatase, AST aspartate aminotransferase, BUN blood urea nitrogen, CK creatine kinase, HCT hematocrit, PAF platelet-activating factor, WBC white blood cell count 5% of previously published benchtop ModELASV CO 2 data [17,25], hence validating benchtop performance. The adult low-flow ECCO 2 R ModELAS was generally well tolerated by the animals.…”

Section: Discussionsupporting

confidence: 67%

“…1a). The benchtop results of our previously reported ECCO 2 R device utilized an identical bundle [17]. The primary difference between the previous and current version of the device are washout holes within the impeller.…”

Section: Methodsmentioning

confidence: 99%

“…1 and normalized to an inlet pCO 2 of 45 mmHg according to Eq. 2 in order to reduce variability resulting from fluctuations of the inlet pCO 2 [17]:…”

Section: Methodsmentioning

confidence: 99%

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In vivo testing of the low-flow CO2 removal application of a compact, platform respiratory device

May

Orizondo

Frankowski

et al. 2020

ICMx

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Background: Non-invasive and lung-protective ventilation techniques may improve outcomes for patients with an acute exacerbation of chronic obstructive pulmonary disease or moderate acute respiratory distress syndrome by reducing airway pressures. These less invasive techniques can fail due to hypercapnia and require transitioning patients to invasive mechanical ventilation. Extracorporeal CO 2 removal devices remove CO 2 independent of the lungs thereby controlling the hypercapnia and permitting non-invasive or lung-protective ventilation techniques. We are developing the Modular Extracorporeal Lung Assist System as a platform technology capable of providing three levels of respiratory assist: adult and pediatric full respiratory support and adult low-flow CO 2 removal. The objective of this study was to evaluate the in vivo performance of our device to achieve low-flow CO 2 removal. Methods: The Modular Extracorporeal Lung Assist System was connected to 6 healthy sheep via a 15.5 Fr dual-lumen catheter placed in the external jugular vein. The animals were recovered and tethered within a pen while supported by the device for 7 days. The pump speed was set to achieve a targeted blood flow of 500 mL/min. The extracorporeal CO 2 removal rate was measured daily at a sweep gas independent regime. Hematological parameters were measured pre-operatively and regularly throughout the study. Histopathological samples of the end organs were taken at the end of each study. Results: All animals survived the surgery and generally tolerated the device well. One animal required early termination due to a pulmonary embolism. Intra-device thrombus formation occurred in a single animal due to improper anticoagulation. The average CO 2 removal rate (normalized to an inlet pCO 2 of 45 mmHg) was 75.6 ± 4.7 mL/min and did not significantly change over the course of the study (p > 0.05). No signs of consistent hemolysis or end organ damage were observed. Conclusion: These in vivo results indicate positive performance of the Modular Extracorporeal Lung Assist System as a low-flow CO 2 removal device.

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Section: Discussionsupporting

confidence: 67%

Section: Methodsmentioning

confidence: 99%

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In vivo testing of the low-flow CO2 removal application of a compact, platform respiratory device

May

Orizondo

Frankowski

et al. 2020

ICMx

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“…Similar to our approach, de Villiers Hugo et al have created a dual mock to investigate a low-flow system with a modified dialysis unit [8]. Unlike most of the described mocks, our construction allows to measure continuously [1,10,13]. Using N 2 and CO 2 as sweep gases on the primary circuit, a constant venous milieu with a p v CO 2 of 45 ± 5 mmHg can be established throughout the whole measurement series.…”

Section: Impact Of Hcl Infusion On Co 2 Removalmentioning

confidence: 99%

A mock circulation loop to test extracorporeal CO2 elimination setups

Schwärzel

Jungmann

Schmoll

et al. 2020

ICMx

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Background Extracorporeal carbon dioxide removal (ECCO2R) is a promising yet limited researched therapy for hypercapnic respiratory failure in acute respiratory distress syndrome and exacerbated chronic obstructive pulmonary disease. Herein, we describe a new mock circuit that enables experimental ECCO2R research without animal models. In a second step, we use this model to investigate three experimental scenarios of ECCO2R: (I) the influence of hemoglobin concentration on CO2 removal. (II) a potentially portable ECCO2R that uses air instead of oxygen, (III) a low-flow ECCO2R that achieves effective CO2 clearance by recirculation and acidification of the limited blood volume of a small dual lumen cannula (such as a dialysis catheter). Results With the presented ECCO2R mock, CO2 removal rates comparable to previous studies were obtained. The mock works with either fresh porcine blood or diluted expired human packed red blood cells. However, fresh porcine blood was preferred because of better handling and availability. In the second step of this work, hemoglobin concentration was identified as an important factor for CO2 removal. In the second scenario, an air-driven ECCO2R setup showed only a slightly lower CO2 wash-out than the same setup with pure oxygen as sweep gas. In the last scenario, the low-flow ECCO2R, the blood flow at the test membrane lung was successfully raised with a recirculation channel without the need to increase cannula flow. Low recirculation ratios resulted in increased efficiency, while high recirculation ratios caused slightly reduced CO2 removal rates. Acidification of the CO2 depleted blood in the recirculation channel caused an increase in CO2 removal rate. Conclusions We demonstrate a simple and cost effective, yet powerful, “in-vitro” ECCO2R model that can be used as an alternative to animal experiments for many research scenarios. Moreover, in our approach parameters such as hemoglobin level can be modified more easily than in animal models.

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“…It should be noted that insufficient elimination of CO 2 causes blood acidosis (blood's pH reduction) and leads to hypercapnia, whereas excess elimination of CO 2 may result in blood alkalosis and some other pathophysiological problems . Moreover, several state‐of‐art therapeutical applications of HFMOs are basically designed to eliminate a part of blood's carbon dioxide content, such as arteriovenous CO 2 removal and venovenous CO 2 removal, jointly referred as extracorporeal CO 2 removal (ECCO 2 R) . In fact, ECCO 2 R reduces the CO 2 concentration of mixed venous blood and as a consequence, the respiration frequency of patient declines, which in turn, facilitates the amelioration of diseased lung …”

Section: Introductionmentioning

confidence: 99%

A pH‐based experimental method for carbon dioxide exchange evaluation in cylindrical hollow fiber membrane oxygenators

Tabesh

Gholami

Torabi

et al. 2019

Asia-Pacific J Chem Eng

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Carbon dioxide transfer rate (CTR) is an important performance characteristic of a hollow fiber membrane oxygenator (HFMO), which is used as an artificial lung in clinical practices. In vitro measurement of CTR through HFMOs is challenging specifically in investigations with natural blood. In this study, a straightforward and applicable method is presented in order to simulate blood CO 2 exchange through HFMOs and consequently calculate the corresponding CTR. The method is based on CO 2 dissociation in deionized water resulting in pH drop of the aqueous solution. The results of proposed method are then validated comparing with in vitro investigations using native porcine blood (NPB) in two types of commercially available HFMOs. Moreover, an innovative relationship between effective membrane surface area, blood retention time, and mixing ratio of CO 2 and N 2 gases in pH drop experiment is introduced in order to simulate the CTR of complicated NPB investigations. The results reveal a good agreement between pH-based calculated CTRs and those investigated conventionally using NPB. This method would be principally applicable not only for other cylindrical HFMOs but also for other configurations of hollow fiber membrane contactors.

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Bench Validation of a Compact Low-Flow CO2 Removal Device

Cited by 16 publications

References 32 publications

In vivo testing of the low-flow CO2 removal application of a compact, platform respiratory device

In vivo testing of the low-flow CO2 removal application of a compact, platform respiratory device

A mock circulation loop to test extracorporeal CO2 elimination setups

A pH‐based experimental method for carbon dioxide exchange evaluation in cylindrical hollow fiber membrane oxygenators

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