Effect of Impeller Design and Spacing on Gas Exchange in a Percutaneous Respiratory Assist Catheter

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

doi:10.1111/aor.12308

Cited by 11 publications

(10 citation statements)

References 36 publications

(51 reference statements)

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“…Though path length is increased, the increased enhancement is due to velocity increase as residence time is slightly reduced with increasing path length (residence time is 2.1s for FB-F, 2.8s for FB-1). Devices in the past have utilized “active mixing” to reduce boundary layer thickness 23–26 however in this study we achieved this through a simple geometric means thus ensuring low hemolysis.…”

Section: Discussionmentioning

confidence: 99%

“…In other respiratory assist applications, “active mixing” has been used as a means to increase the fluid velocity past fiber surfaces by using ancillary components like rotating impellers adjacent to the fiber bundle or rotating the fiber bundle itself within a stationary housing. 23–26 In this study, we investigated a simpler, passive means to improve mass transfer efficiency in hollow fiber bundles by manipulating their form factor to increase the fluid velocity past fiber surfaces. We used a simple 1D model of blood flow and gas exchange in hollow fiber bundles based on a previously published mass transfer correlation 24 to characterize oxygenation efficiency as a function of fiber bundle diameter.…”

Section: Introductionmentioning

confidence: 99%

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Fiber Bundle Design for an Integrated Wearable Artificial Lung

Madhani¹,

Frankowski²,

Federspiel³

2017

ASAIO Journal

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Mechanical ventilation and ECMO are the only viable treatment options for lung failure patients at the end stage, including ARDS and COPD. These treatments however are associated with high morbidity and mortality due to long wait times for lung transplant. Contemporary clinical literature has shown ambulation improves post-transplant outcomes in lung failure patients. Given this, we are developing the PAAL, a truly wearable artificial lung that allows for ambulation. In this study, we targeted 180 ml/min oxygenation and determined the form factor for a hollow fiber membrane (HFM) bundle for the PAAL. Based on a previously published mass transfer correlation we modeled oxygenation efficiency as a function of fiber bundle diameter. Three benchmark fiber bundles were fabricated to validate the model through in-vitro blood gas exchange at blood flow rates from 1 to 4 L/min according to ASTM standards. We used the model to determine a final design, which was characterized in-vitro through a gas exchange as well as a hemolysis study at 3.5 L/min The percent difference between model predictions and experiment for the benchmark bundles ranged from 3% to 17.5% at the flowrates tested. Using the model, we predicted a 1.75 inch diameter bundle with 0.65 m2 surface area would produce 180 ml/min at 3.5 L/min blood flow rate. The oxygenation efficiency was 278 ml/min/m2 and the Normalized Index of Hemolysis (NIH) was less than 0.05g/100L. Future work involves integrating this bundle into the PAAL for which an experimental prototype is under development in our laboratory.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fiber Bundle Design for an Integrated Wearable Artificial Lung

Madhani¹,

Frankowski²,

Federspiel³

2017

ASAIO Journal

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“…Mechanisms which reduce the diffusional boundary layer resistance and conditions which promote local bicarbonate/CO 2 disequilibrium, such as fluid longer transit times, will result in the largest contribution from the CA coating. Development is underway on CO 2 removal devices which reduce the boundary layer resistance by increasing fluid velocity past HFMs through mechanical mixing independent of fluid flow rate through the device [22–24]. This approach increases delivery of bicarbonate/CO 2 to the HFM surface without decreasing blood transit time, which may take advantage of CA’s rapid catalysis and boost CO 2 removal performance from increased substrate delivery.…”

Section: Discussionmentioning

confidence: 99%

Kinetics of CO2 exchange with carbonic anhydrase immobilized on fiber membranes in artificial lungs

Arazawa

Kimmel

Federspiel

2015

J Mater Sci: Mater Med

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Artificial lung devices comprised of hollow fiber membranes (HFMs) coated with the enzyme carbonic anhydrase (CA), accelerate removal of carbon dioxide (CO2) from blood for the treatment of acute respiratory failure. While previous work demonstrated CA coatings increase HFM CO2 removal by 115 % in phosphate buffered saline (PBS), testing in blood revealed a 36 % increase compared to unmodified HFMs. In this work, we sought to characterize the CO2 mass transport processes within these biocatalytic devices which impede CA coating efficacy and develop approaches towards improving bioactive HFM efficiency. Aminated HFMs were sequentially reacted with glutaraldehyde (GA), chitosan, GA and afterwards incubated with a CA solution, covalently linking CA to the surface. Bioactive CA-HFMs were potted in model gas exchange devices (0.0119 m2) and tested for esterase activity and CO2 removal under various flow rates with PBS, whole blood, and solutions containing individual blood components (plasma albumin, red blood cells or free carbonic anhydrase). Results demonstrated that increasing the immobilized enzyme activity did not significantly impact CO2 removal rate, as the diffusional resistance from the liquid boundary layer is the primary impediment to CO2 transport by both unmodified and bioactive HFMs under clinically relevant conditions. Furthermore, endogenous CA within red blood cells competes with HFM immobilized CA to increase CO2 removal. Based on our findings, we propose a bicarbonate/CO2 disequilibrium hypothesis to describe performance of CA-modified devices in both buffer and blood. Improvement in CO2 removal rates using CA-modified devices in blood may be realized by maximizing bicarbonate/CO2 disequilibrium at the fiber surface via strategies such as blood acidification and active mixing within the device.

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“…Garrett Jeffries et al. of the University of Pittsburgh, Pittsburgh, PA, USA, reported on the effect of impeller design and spacing on gas exchange in a percutaneous respiratory assist catheter (IPRAC). The effects of the design and spacing were carried out using CFD and in vitro deionized water gas exchange testing.…”

Section: Pulmonary Supportmentioning

confidence: 99%

Artificial Organs 2014: A Year in Review

Malchesky¹

2015

Artificial Organs

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In this Editor's Review, articles published in 2014 are organized by category and briefly summarized. We aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. As the official journal of the International Federation for Artificial Organs, the International Faculty for Artificial Organs, the International Society for Rotary Blood Pumps, the International Society for Pediatric Mechanical Cardiopulmonary Support, and the Vienna International Workshop on Functional Electrical Stimulation, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers, the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons, for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.

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Effect of Impeller Design and Spacing on Gas Exchange in a Percutaneous Respiratory Assist Catheter

Cited by 11 publications

References 36 publications

Fiber Bundle Design for an Integrated Wearable Artificial Lung

Fiber Bundle Design for an Integrated Wearable Artificial Lung

Kinetics of CO2 exchange with carbonic anhydrase immobilized on fiber membranes in artificial lungs

Artificial Organs 2014: A Year in Review

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