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

Alexandra G May; Ryan A Orizondo; Brian J Frankowski; Sang-Ho Ye; Ergin Kocyildirim; William R Wagner; Jonathan D'Cunha; William J Federspiel

doi:10.1186/s40635-020-00329-9

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

Intensive Care Med Exp. 2020 Aug 17;8(1):45. doi: 10.1186/s40635-020-00329-9.

Authors

Alexandra G May^{1

2}, Ryan A Orizondo^{2

3}, Brian J Frankowski², Sang-Ho Ye^{2

4}, Ergin Kocyildirim^{2

5}, William R Wagner^{1

2

4

6}, Jonathan D'Cunha⁷, William J Federspiel^{8

9

10

11

12}

Affiliations

¹ Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, USA.
² McGowan Institute for Regenerative Medicine, University of Pittsburgh, 3025 East Carson Street, Pittsburgh, PA, 15203, USA.
³ Department of Medicine, University of Pittsburgh, Pittsburgh, USA.
⁴ Department of Surgery, University of Pittsburgh, Pittsburgh, USA.
⁵ Department of Cardiothoracic Surgery, Children's Hospital of Pittsburgh, Pittsburgh, USA.
⁶ Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA.
⁷ Division of Lung Transplantation/Lung Failure, Department of Cardiothoracic Surgery, University of Pittsburgh Medical Center, Pittsburgh, USA.
⁸ Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, USA. wfedersp@pitt.edu.
⁹ McGowan Institute for Regenerative Medicine, University of Pittsburgh, 3025 East Carson Street, Pittsburgh, PA, 15203, USA. wfedersp@pitt.edu.
¹⁰ Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA. wfedersp@pitt.edu.
¹¹ Department of Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, USA. wfedersp@pitt.edu.
¹² Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, USA. wfedersp@pitt.edu.

Abstract

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 CO₂ removal devices remove CO₂ 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 CO₂ removal. The objective of this study was to evaluate the in vivo performance of our device to achieve low-flow CO₂ 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 CO₂ 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 CO₂ removal rate (normalized to an inlet pCO₂ 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 CO₂ removal device.

Keywords: Carbon dioxide; Extracorporeal CO2 removal; Hypercapnia.

Abstract

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