scholarly journals Alkaline Liquid Ventilation of the Membrane Lung for Extracorporeal Carbon Dioxide Removal (ECCO2R): In Vitro Study

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 464
Author(s):  
Luigi Vivona ◽  
Michele Battistin ◽  
Eleonora Carlesso ◽  
Thomas Langer ◽  
Carlo Valsecchi ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
In Vitro Study ◽  
Carbon Dioxide Removal ◽  
Co2 Removal ◽  
Liquid Ventilation ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Membrane Lung ◽  
Polypropylene Membrane ◽  
Removal Capacity

Extracorporeal carbon dioxide removal (ECCO2R) is a promising strategy to manage acute respiratory failure. We hypothesized that ECCO2R could be enhanced by ventilating the membrane lung with a sodium hydroxide (NaOH) solution with high CO2 absorbing capacity. A computed mathematical model was implemented to assess NaOH–CO2 interactions. Subsequently, we compared NaOH infusion, named “alkaline liquid ventilation”, to conventional oxygen sweeping flows. We built an extracorporeal circuit with two polypropylene membrane lungs, one to remove CO2 and the other to maintain a constant PCO2 (60 ± 2 mmHg). The circuit was primed with swine blood. Blood flow was 500 mL × min−1. After testing the safety and feasibility of increasing concentrations of aqueous NaOH (up to 100 mmol × L−1), the CO2 removal capacity of sweeping oxygen was compared to that of 100 mmol × L−1 NaOH. We performed six experiments to randomly test four sweep flows (100, 250, 500, 1000 mL × min−1) for each fluid plus 10 L × min−1 oxygen. Alkaline liquid ventilation proved to be feasible and safe. No damages or hemolysis were detected. NaOH showed higher CO2 removal capacity compared to oxygen for flows up to 1 L × min−1. However, the highest CO2 extraction power exerted by NaOH was comparable to that of 10 L × min−1 oxygen. Further studies with dedicated devices are required to exploit potential clinical applications of alkaline liquid ventilation.

Carbon dioxide removal using low bicarbonate dialysis in rodents

Perfusion ◽  
2019 ◽  
Vol 34 (7) ◽  
pp. 578-583 ◽  
Author(s):  
Lien H Vu ◽  
John A Kellum ◽  
William J Federspiel ◽  
Matthew E Cove
Keyword(s):  
Carbon Dioxide ◽  
In Vitro Study ◽  
Blood Gases ◽  
Carbon Dioxide Removal ◽  
Low Flow ◽  
Sprague Dawley ◽  
Bicarbonate Concentration ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Arterial Ph

Background: Extracorporeal carbon dioxide removal may be used to manage hypercapnia, but compared to dialysis, it’s not widely available. A recent in vitro study showed that dialysis with low bicarbonate dialysates removes CO2. Objective: To show that bicarbonate dialysis removes CO2 in an animal model to validate in-vitro findings and quantify the effect on arterial pH. Methods: Male Sprague-Dawley hypercapnic rats were dialyzed with either a conventional dialysate (PrismasolTM) or a bicarbonate-free dialysate (Bicarb0). The effect of dialysis on standard blood gases and electrolytes was measured. Results: Partial pressure of CO2 and bicarbonate concentration in blood decreased significantly after exposure to Bicarb0 compared to PrismasolTM (filter outflow values 12.8 vs 81.1 mmHg; p < 0.01 for CO2 and 3.5 vs 22.0 mmol/L; p < 0.01 for bicarbonate). Total CO2 content of blood was reduced by 459 mL/L during dialysis with Bicarb0 (filter inflow 546 ± 91 vs filter outflow 87 ± 52 mL/L; p < 0.01), but was not significantly reduced with PrismasolTM. Conclusions: Bicarbonate dialysis removes CO2 at rates comparable to existing low-flow ECCO2R.

Regional Blood Acidification Enhances Extracorporeal Carbon Dioxide Removal

2014 ◽  
Vol 120 (2) ◽  
pp. 416-424 ◽  
Author(s):  
Alberto Zanella ◽  
Paolo Mangili ◽  
Sara Redaelli ◽  
Vittorio Scaravilli ◽  
Marco Giani ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Lactic Acid ◽  
Blood Flow Rate ◽  
Carbon Dioxide Removal ◽  
Low Flow ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Membrane Lung ◽  
Extracorporeal Blood ◽  
Patients At Risk

Abstract Background: Extracorporeal carbon dioxide removal has been proposed to achieve protective ventilation in patients at risk for ventilator-induced lung injury. In an acute study, the authors previously described an extracorporeal carbon dioxide removal technique enhanced by regional extracorporeal blood acidification. The current study evaluates efficacy and feasibility of such technology applied for 48 h. Methods: Ten pigs were connected to a low-flow veno-venous extracorporeal circuit (blood flow rate, 0.25 l/min) including a membrane lung. Blood acidification was achieved in eight pigs by continuous infusion of 2.5 mEq/min of lactic acid at the membrane lung inlet. The acid infusion was interrupted for 1 h at the 24 and 48 h. Two control pigs did not receive acidification. At baseline and every 8 h thereafter, the authors measured blood lactate, gases, chemistry, and the amount of carbon dioxide removed by the membrane lung (VCO2ML). The authors also measured erythrocyte metabolites and selected cytokines. Histological and metalloproteinases analyses were performed on selected organs. Results: Blood acidification consistently increased VCO2ML by 62 to 78%, from 79 ± 13 to 128 ± 22 ml/min at baseline, from 60 ± 8 to 101 ± 16 ml/min at 24 h, and from 54 ± 6 to 96 ± 16 ml/min at 48 h. During regional acidification, arterial pH decreased slightly (average reduction, 0.04), whereas arterial lactate remained lower than 4 mEq/l. No sign of organ and erythrocyte damage was recorded. Conclusion: Infusion of lactic acid at the membrane lung inlet consistently increased VCO2ML providing a safe removal of carbon dioxide from only 250 ml/min extracorporeal blood flow in amounts equivalent to 50% production of an adult man.

scholarly journals Comparison of Circular and Parallel-Plated Membrane Lungs for Extracorporeal Carbon Dioxide Elimination

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 398
Author(s):  
Leonie S. Schwärzel ◽  
Anna M. Jungmann ◽  
Nicole Schmoll ◽  
Stefan Caspari ◽  
Frederik Seiler ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Flow ◽  
Removal Rate ◽  
Low Flow ◽  
Chronic Obstructive ◽  
Co2 Removal ◽  
Circular Membrane ◽  
Flow Rates ◽  
Polypropylene Membrane ◽  
Removal Capacity

Extracorporeal carbon dioxide removal (ECCO2R) is an important technique to treat critical lung diseases such as exacerbated chronic obstructive pulmonary disease (COPD) and mild or moderate acute respiratory distress syndrome (ARDS). This study applies our previously presented ECCO2R mock circuit to compare the CO2 removal capacity of circular versus parallel-plated membrane lungs at different sweep gas flow rates (0.5, 2, 4, 6 L/min) and blood flow rates (0.3 L/min, 0.9 L/min). For both designs, two low-flow polypropylene membrane lungs (Medos Hilte 1000, Quadrox-i Neonatal) and two mid-flow polymethylpentene membrane lungs (Novalung Minilung, Quadrox-iD Pediatric) were compared. While the parallel-plated Quadrox-iD Pediatric achieved the overall highest CO2 removal rates under medium and high sweep gas flow rates, the two circular membrane lungs performed relatively better at the lowest gas flow rate of 0.5 L/min. The low-flow Hilite 1000, although overall better than the Quadrox i-Neonatal, had the most significant advantage at a gas flow of 0.5 L/min. Moreover, the circular Minilung, despite being significantly less efficient than the Quadrox-iD Pediatric at medium and high sweep gas flow rates, did not show a significantly worse CO2 removal rate at a gas flow of 0.5 L/min but rather a slight advantage. We suggest that circular membrane lungs have an advantage at low sweep gas flow rates due to reduced shunting as a result of their fiber orientation. Efficiency for such low gas flow scenarios might be relevant for possible future portable ECCO2R devices.

Antilisterial Effects of a Sorbate-Nisin Combination In Vitro and on Packaged Beef at Refrigeration Temperature

1997 ◽  
Vol 60 (9) ◽  
pp. 1075-1080 ◽  
Author(s):  
SHERYL M. AVERY ◽  
SAVA BUNCIC
Keyword(s):  
Carbon Dioxide ◽  
In Vitro Study ◽  
Clinical Strain ◽  
Lag Phase ◽  
Initial Population ◽  
Pathogen Load ◽  
Beef Steaks ◽  
Packaged Beef ◽  
Phosphate Buffered Saline

The antilisterial effects of a sorbate-nisin combination were assessed in vitro and on beef at refrigeration temperature. Three hemolytic pathogenic strains of Listeria monocytogenes, reference strain NCTC 7973, food strain L70, and clinical strain L94, were stored at 4°C in phosphate-buffered saline, pH 5.5, containing a combination of sorbate (0.2% wt/vol) and nisin (40 IU/ml). After 4 weeks, hemolysin production by the strains had ceased, their subsequent lag phases at 37°C were extended from an initial 1.23 to 1.32 h to a final 7.13 to 8.06 h and their pathogenicity for chick embryos had decreased from an initial 93.3 to 95.5% to a final 43.3 to 60.0%. Sterile beef steaks of normal pH (5.4 to 5.5) were inoculated with a cocktail of the three strains at approximately 5 log CFU/cm2 and the surface of half the steaks was treated with the antimicrobial solution 1.0% sorbate plus 1,000 IU of nisin per ml. The meat was packaged under vacuum or 100% carbon dioxide and stored at 4°C for 4 weeks. On untreated meat, L. monocytogenes grew by 1.79 log cycles in vacuum packages, but in CO2 packages the initial population decreased by 0.54 log cycle. On treated vacuum-packaged meat, L. monocytogenes decreased during storage to the extent that 96.5% of the initial pathogen load was eliminated, but the lag phase of the remaining cells at 37°C was unaffected. On treated CO2-packaged meat L. monocytogenes decreased during storage to the extent that 89.3% of the initial pathogen load was eliminated, and for surviving cells the lag phase at 37°C was extended. Treatment with the sorbate-nisin combination did not significantly affect pathogenicity of the L. monocytogenes cocktail recovered from vacuum- or carbon dioxide-packages after storage, in contrast to the in vitro study, where pathogenicity was clearly attenuated. The reason for this difference is unknown.

scholarly journals A Proof of Concept Study, Demonstrating Extracorporeal Carbon Dioxide Removal Using Hemodialysis with a Low Bicarbonate Dialysate

ASAIO Journal ◽  
2019 ◽  
Vol 65 (6) ◽  
pp. 605-613 ◽  
Author(s):  
Matthew E. Cove ◽  
Lien Hong Vu ◽  
Troels Ring ◽  
Alexandra G. May ◽  
William J. Federspiel ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Removal ◽  
Proof Of Concept ◽  
Extracorporeal Carbon Dioxide Removal ◽  
Concept Study
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