Blood Trauma Induced by Clinically Accepted Oxygenators

Kawahito, Shinji; Maeda, Takeshi; Yoshikawa, Masaharu; Tamaki, Toru; Nonaka, Kenji; Linneweber, Joerg; Mikami, Masayuki; Motomura, Tadashi; Ichikawa, Shuhei; Glueck, Julie; Nosé, Yukihiko

doi:10.1097/00002480-200109000-00019

Cited by 35 publications

(34 citation statements)

References 15 publications

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“…Normalized index of hemolysis (NIH) calculations, indicating the estimated grams of hemoglobin released to plasma per 100 L of blood flow, did not exceed 0.005 g/100 L for any impeller or arrangement evaluated. NIH values at this level are considered acceptable when compared with clinically available oxygenator devices (34,35); however, conclusive in vitro testing has not been completed to verify or dispute the CFD predictions. Subsequent to all in vitro testing, both gas exchange and hemocompatibility of full IPRAC prototypes will be verified in acute in vivo bovine studies.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2014

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Providing partial respiratory assistance by removing carbon dioxide (CO2) can improve clinical outcomes in patients suffering from acute exacerbations of chronic obstructive pulmonary disease and acute respiratory distress syndrome. An intravenous respiratory assist device with a small (25 Fr) insertion diameter eliminates the complexity and potential complications associated with external blood circuitry and can be inserted by nonspecialized surgeons. The impeller percutaneous respiratory assist catheter (IPRAC) is a highly efficient CO2 removal device for percutaneous insertion to the vena cava via the right jugular or right femoral vein that utilizes an array of impellers rotating within a hollow-fiber membrane bundle to enhance gas exchange. The objective of this study was to evaluate the effects of new impeller designs and impeller spacing on gas exchange in the IPRAC using computational fluid dynamics (CFD) and in vitro deionized water gas exchange testing. A CFD gas exchange and flow model was developed to guide a progressive impeller design process. Six impeller blade geometries were designed and tested in vitro in an IPRAC device with 2- or 10-mm axial spacing and varying numbers of blades (2–5). The maximum CO2 removal efficiency (exchange per unit surface area) achieved was 573 ± 8 mL/min/m2 (40.1 mL/min absolute). The gas exchange rate was found to be largely independent of blade design and number of blades for the impellers tested but increased significantly (5–10%) with reduced axial spacing allowing for additional shaft impellers (23 vs. 14). CFD gas exchange predictions were within 2–13% of experimental values and accurately predicted the relative improvement with impellers at 2- versus 10-mm axial spacing. The ability of CFD simulation to accurately forecast the effects of influential design parameters suggests it can be used to identify impeller traits that profoundly affect facilitated gas exchange.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2014

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“…In-vitro the PAAL produced sufficient oxygenation (180 ml/min) as well as CO 2 removal (150 ml/min) at 3.5 L/min while still maintaining a low level of hemolysis (NIH 0.054 g/100L) compared to clinically accepted oxygenators 23 . Of the measured in-vitro hemolysis, only a portion (60%) is due the device, the rest is attributed to the cannula.…”

Section: Discussionmentioning

confidence: 93%

“…The fiber bundle is manufactured using commercially available Membrana® PMP 90/200 type hollow fiber sheets (44 fibers/inch) (Membrana GmbH, Wuppertal, Germany) and is potted round to eliminate corners. Bundle manufacturing further described elsewhere 23 . The device components are designed in SolidWorks (Dassault Systèmes, Waltham, MA) and CNC-machined from clear polymethyl methacrylate.…”

Section: Methodsmentioning

confidence: 99%

In vitro and in vivo evaluation of a novel integrated wearable artificial lung

Madhani

Frankowski

Burgreen

et al. 2017

The Journal of Heart and Lung Transplantation

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Background Conventional ECMO is cumbersome and is associated with high morbidity and mortality. We are developing the Paracorporeal Ambulatory Assist Lung (PAAL), designed to ambulate lung failure patients during bridge to transplant or recovery. In this study, we investigated the in-vitro and acute in-vivo performance of the PAAL. Methods The PAAL features a 1.75 inch diameter cylindrical HFM bundle of stacked sheets, with a surface area of 0.65 m2 integrated with a centrifugal pump. The PAAL was tested on the bench for hydrodynamic performance, gas exchange and hemolysis. The PAAL was then tested in 40–60 kg adult sheep (n=4) for 6h. The animals were cannulated with an Avalon Elite 27 Fr. DLC inserted through the right external jugular into the SVC, RA and IVC. Results The PAAL pumped over 250 mmHg at 3.5 L/min at a rotation speed of 2100 RPM. Oxygenation performance met the target of 180 ml/min at 3.5 L/min of blood flow in vitro, resulting in a gas exchange efficiency of 278 ml/min/m2. The normalized index of hemolysis (NIH) for the PAAL and cannula was 0.054 g/100L (n=2) at 3.5 L/min, as compared to 0.020 g/100L (n=2) for control (DLC cannula and a Centrimag pump). Plasma-free hemoglobin (pfHb) was below 20 mg/dL for all animals. Blood left the device 100% oxygenated in vivo and oxygenation reached 181 ml/min at 3.8 L/min. Conclusions The PAAL met in vitro and acute in vivo performance targets. 5 day chronic sheep studies are planned in the near term.

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“…Further, these NIH values are within the acceptable limits (NIH < 0.05 g/100L) of hemolysis for clinically approved oxygenators. 31 As blood flows over HFMs, a fluid boundary layer forms at the surface of the fibers. The thickness of the boundary layer is related to flow velocity past fibers.…”

Section: Discussionmentioning

confidence: 99%

“…The PAAL requirements based on other device used clinically and under research development include 19–21 a small form factor, long-term (1–3 month) durability, 180 ml/min oxygenation at 3.5 L/min for providing partial to complete lung support, compatibility with the Avalon Elite ® DLC and a normalized index of hemolysis (NIH) under 0.05 g/100L. 31 The small form factor can be achieved by minimizing the size of the HFM bundle, which typically represents the largest component of the pump oxygenator system. In turn, a smaller HFM bundle requires a design with increased gas exchange efficiency.…”

Section: Introductionmentioning

confidence: 99%

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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Blood Trauma Induced by Clinically Accepted Oxygenators

Cited by 35 publications

References 15 publications

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

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

In vitro and in vivo evaluation of a novel integrated wearable artificial lung

Fiber Bundle Design for an Integrated Wearable Artificial Lung

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