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

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.

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Biological treatment characteristics of benzene and toluene in a biofilter packed with cylindrical activated carbon

Water Science & Technology ◽

10.2166/wst.2002.0716 ◽

2002 ◽

Vol 46 (11-12) ◽

pp. 51-56 ◽

Cited By ~ 3

Author(s):

G.-W. Li ◽

H.-Y. Hu ◽

J.-M. Hao ◽

H.-Q. Zhang

Keyword(s):

Carbon Dioxide ◽

Activated Carbon ◽

Gas Flow ◽

Removal Rate ◽

Carbon Dioxide Concentration ◽

Organic Load ◽

Filler Materials ◽

Removal Capacity ◽

Bacillus Spore ◽

Maximum Removal

The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas flow rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3.h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3.h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m−3.h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.

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Development of a CO2 Sensor for Extracorporeal Life Support Applications

Sensors ◽

10.3390/s20133613 ◽

2020 ◽

Vol 20 (13) ◽

pp. 3613

Author(s):

Michele Bellancini ◽

Laura Cercenelli ◽

Stefano Severi ◽

Guido Comai ◽

Emanuela Marcelli

Keyword(s):

Carbon Dioxide ◽

Gas Flow ◽

Life Support ◽

Removal Rate ◽

Extracorporeal Life Support ◽

Co2 Concentration ◽

Co2 Removal ◽

Exhaust Gas ◽

Membrane Oxygenator

Measurement of carbon dioxide (CO2) in medical applications is a well-established method for monitoring patient’s pulmonary function in a noninvasive way widely used in emergency, intensive care, and during anesthesia. Even in extracorporeal-life support applications, such as Extracorporeal Carbon Dioxide Removal (ECCO2R), Extracorporeal Membrane Oxygenation (ECMO), and cardiopulmonary by-pass (CPB), measurement of the CO2 concentration in the membrane oxygenator exhaust gas is proven to be useful to evaluate the treatment progress as well as the performance of the membrane oxygenator. In this paper, we present a new optical sensor specifically designed for the measurement of CO2 concentration in oxygenator exhaust gas. Further, the developed sensor allows measurement of the gas flow applied to the membrane oxygenator as well as the estimation of the CO2 removal rate. A heating module is implemented within the sensor to avoid water vapor condensation. Effects of temperature on the sensor optical elements of the sensors are disclosed, as well as a method to avoid signal–temperature dependency. The newly developed sensor has been tested and compared against a reference device routinely used in clinical practice in both laboratory and in vivo conditions. Results show that sensor accuracy fulfills the requirements of the ISO standard, and that is suitable for clinical applications.

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

Membranes ◽

10.3390/membranes11070464 ◽

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.

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Evaluation of a New Extracorporeal CO2 Removal Device in an Experimental Setting

Membranes ◽

10.3390/membranes11010008 ◽

2020 ◽

Vol 11 (1) ◽

pp. 8

Author(s):

Matteo Di Nardo ◽

Filippo Annoni ◽

Fuhong Su ◽

Mirko Belliato ◽

Roberto Lorusso ◽

...

Keyword(s):

Blood Flow ◽

Gas Flow ◽

High Surface ◽

Surface Membrane ◽

Respiratory Acidosis ◽

Chronic Obstructive ◽

Gas Flows ◽

Co2 Removal ◽

Extracorporeal Co2 Removal ◽

Membrane Lung

Background: Ultra-protective lung ventilation in acute respiratory distress syndrome or early weaning and/or avoidance of mechanical ventilation in decompensated chronic obstructive pulmonary disease may be facilitated by the use of extracorporeal CO2 removal (ECCO2R). We tested the CO2 removal performance of a new ECCO2R (CO2RESET) device in an experimental animal model. Methods: Three healthy pigs were mechanically ventilated and connected to the CO2RESET device (surface area = 1.8 m2, EUROSETS S.r.l., Medolla, Italy). Respiratory settings were adjusted to induce respiratory acidosis with the adjunct of an external source of pure CO2 (target pre membrane lung venous PCO2 (PpreCO2): 80–120 mmHg). The amount of CO2 removed (VCO2, mL/min) by the membrane lung was assessed directly by the ECCO2R device. Results: Before the initiation of ECCO2R, the median PpreCO2 was 102.50 (95.30–118.20) mmHg. Using fixed incremental steps of the sweep gas flow and maintaining a fixed blood flow of 600 mL/min, VCO2 progressively increased from 0 mL/min (gas flow of 0 mL/min) to 170.00 (160.00–200.00) mL/min at a gas flow of 10 L/min. In particular, a high increase of VCO2 was observed increasing the gas flow from 0 to 2 L/min, then, VCO2 tended to progressively achieve a steady-state for higher gas flows. No animal or pump complications were observed. Conclusions: Medium-flow ECCO2R devices with a blood flow of 600 mL/min and a high surface membrane lung (1.8 m2) provided a high VCO2 using moderate sweep gas flows (i.e., >2 L/min) in an experimental swine models with healthy lungs.

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The impact of fresh gas flow on wash-in, wash-out time and gas consumption for sevoflurane and desflurane, comparing two anaesthesia machines, a test-lung study.

F1000Research ◽

10.12688/f1000research.13064.2 ◽

2017 ◽

Vol 6 ◽

pp. 1997 ◽

Cited By ~ 2

Author(s):

Fredrik Leijonhufvud ◽

Fredrik Jöneby ◽

Jan G. Jakobsson

Keyword(s):

Gas Flow ◽

Anaesthetic Agent ◽

Point Of View ◽

Low Flow ◽

Test Lung ◽

Minimal Alveolar Concentration ◽

Flow Rates ◽

Optimal Flow ◽

Gas Consumption ◽

The Impact

Low-flow anaesthesia is considered beneficial for the patient and the environment, and it is cost reducing due to reduced anaesthetic gas consumption. An initial high-flow to saturate the circle system ( wash-in) is desirable from a clinical point of view. We measured the wash-in and wash-out times (time to saturate and to eliminate the anaesthetic agent, AA), for sevoflurane and desflurane, in a test-lung with fixed 3 MAC vaporizer setting at different fresh gas flow (FGF) and calculated the consumption of AA. We tried to find an optimal flow rate for speed and gas consumption, comparing two anaesthesia machines (AMs): Aisys and Flow-i. Time to reach 1 minimal alveolar concentration (MAC) (wash-in) decreased (p<0.05) at higher flow rates (1 – 2 – 4) but plateaued at 4-4.8 l/min. The consumption of AA was at its lowest around 4-4.8 l/min (optimal flow) for all but the Aisys /desflurane group. Wash-out times decreased as FGF increased, until reaching plateau at FGF of 4-6 l/min. Aisys had generally shorter wash-in times at flow rates < 4 l/min as well as lower consumption of AA. At higher flow rates there were little difference between the AMs. The “optimal FGF” for wash-out, elimination of gas from the test-lung and circle system, plateaued with no increase in speed beyond 6 l/min. A fresh gas flow of 4 l/min. seems “optimal” taking speed to reach a 1 MAC ET and gas consumption into account during wash-in with a fixed 3 MAC vaporizer setting, and increasing fresh gas flow beyond 6 l/min does not seem to confirm major benefit during wash-out.

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Multiple propane gas flow rates procedure to determine accuracy and linearity of indirect calorimetry systems : An experimental assessment of a method.

10.7287/peerj.preprints.27550v1 ◽

2019 ◽

Author(s):

Mohammad Ismail ◽

Alsubheen A Sana'a ◽

Angela Loucks-Atlinson ◽

Matthew Atkinson ◽

Liam P Kelly ◽

...

Keyword(s):

Carbon Dioxide ◽

Indirect Calorimetry ◽

Energy Production ◽

Gas Flow ◽

Carbon Dioxide Production ◽

Whole Body ◽

Gas Flows ◽

Flow Rates ◽

Ventilation Rates ◽

Body Energy

Objective: Indirect calorimetry (IC) systems measure the fractions of expired carbon dioxide (FECO2) and oxygen (FEO2) recorded at the mouth in order to estimate whole body energy production (EP). The fundamental principal of IC relates to oxidative mechanisms, expressed as rate of oxygen uptake (V̇O2) and carbon dioxide production (V̇CO2). From these volumes we calculate energy production and respiratory exchange ratio which is used to estimate substrate utilization rates. The accuracy of IC systems is critical to detect small changes in respiratory gas exchanges. The aim of this technical report was to assess the accuracy and linearity of IC systems using multiple propane gas flow rates procedure. Approach: A series of propane gas with different flow rates and ventilation rates were run on three different IC systems. The actual experimental V̇O2 and V̇CO2 were calculated and compared to stoichiometry theoretical values. Results: showed a linear relationship between gas volumes (V̇O2 and V̇CO2) and propane gas flows (99.6%, 99.2%, 94.8% for the Sable, Moxus, and Jaeger metabolic carts, respectively). In terms of system error, Jaeger system had significantly (p < 0.001) greater V̇O2 (M = -0.057, SE = 0.004), and V̇CO2 (M = -0.048, SE = 0.002) error compared to either the Sable (V̇O2, M = 0.044, SE = 0.004; V̇CO2, M = 0.024, SE = 0.002) or the Moxus (V̇O2, M = 0.046, SE = 0.004; V̇CO2, M = 0.025, SE = 0.002) metabolic carts. There were no significant differences between the Sable or Moxus metabolic carts. Conclusion: The multiple flow rates approach permitted the assessment of linearity of IC systems in addition to determining the accuracy of fractions of expired gases.

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Experimental research of the carbon circle features in “atmosphere – vegetation” system over the wetland area within the forest – steep zone in Ukraine using remote spectro- and gasometry under the global climate changes

Ukrainian journal of remote sensing ◽

10.36023/ujrs.2020.24.166 ◽

2020 ◽

pp. 15-23

Author(s):

Vadim Lyalko ◽

Galyna Zholobak ◽

Stanislav Dugin ◽

Oksana Sybirtseva ◽

Stanislav Golubov ◽

...

Keyword(s):

Carbon Dioxide ◽

Removal Rate ◽

Climatic Changes ◽

Activity Period ◽

Test Plant ◽

Forest Steppe ◽

Co2 Removal ◽

Regional Warming ◽

Vegetative Period ◽

Concentration Changes

Operation of the indicators for the reliable regional carbon dioxide content in atmosphere is the important factor for the computer simulation of climatic changes at the appropriate scale. A goal is the experimental study of the processes for carbon dioxide gas exchange (photosynthesis and respiration) of wetland vegetation for the forest-steppe zone in Ukraine under recent climatic changes in order to determine the quantitative indicators for the CO2 removal rate from the atmosphere by this vegetation. For this the CO2 Qubit Systems s151 (Canada) are used to measure СО2 in air end spectroradiometer FieldSpec® 3FR (USA). This system has got the respiratory flow-through camber, where the test plant is placed. The CO2 concentration changes in this chamber are measured by IR gas analyzer for the certain timespan. Data are processed by LabProInterface. The results obtained for the main wetland plants (Carex riparia and Phragmites australis ) during the spring-summer vegetative period show that the growth of their productivity (CO2 removal rate from atmosphere) takes place only under the environmental temperature of 18-22 о С. Also, it is certain that the positive indicator for these systems is their appreciably longer photosynthetic activity period as compared with the different ecosystems due to the cooling effect of soil moisture in their habitat. It should be taking into account when the measures for minimization of regional warming effects are implemented with the maximally contributing to the reclamation and revivification of the wetlands.

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A mock circulation loop to test extracorporeal CO2 elimination setups

Intensive Care Medicine Experimental ◽

10.1186/s40635-020-00341-z ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Leonie S. Schwärzel ◽

Anna M. Jungmann ◽

Nicole Schmoll ◽

Frederik Seiler ◽

Ralf M. Muellenbach ◽

...

Keyword(s):

Animal Models ◽

Removal Rate ◽

Hemoglobin Concentration ◽

Low Flow ◽

Pure Oxygen ◽

Second Step ◽

Chronic Obstructive ◽

Removal Rates ◽

Porcine Blood ◽

Mock Circulation

Abstract 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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Update on extracorporeal carbon dioxide removal: a comprehensive review on principles, indications, efficiency, and complications

Perfusion ◽

10.1177/0267659120906048 ◽

2020 ◽

Vol 35 (6) ◽

pp. 492-508

Author(s):

Thomas Staudinger

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Removal ◽

Low Flow ◽

Chronic Obstructive ◽

Extracorporeal Carbon Dioxide Removal ◽

Obstructive Pulmonary Disease ◽

Blood Flows ◽

Non Invasive ◽

Non Invasive Ventilation ◽

Exchange Membrane

Technology: Extracorporeal carbon dioxide removal means the removal of carbon dioxide from the blood across a gas exchange membrane without substantially improving oxygenation. Carbon dioxide removal is possible with substantially less extracorporeal blood flow than needed for oxygenation. Techniques for extracorporeal carbon dioxide removal include (1) pumpless arterio-venous circuits, (2) low-flow venovenous circuits based on the technology of continuous renal replacement therapy, and (3) venovenous circuits based on extracorporeal membrane oxygenation technology. Indications: Extracorporeal carbon dioxide removal has been shown to enable more protective ventilation in acute respiratory distress syndrome patients, even beyond the so-called “protective” level. Although experimental data suggest a benefit on ventilator induced lung injury, no hard clinical evidence with respect to improved outcome exists. In addition, extracorporeal carbon dioxide removal is a tool to avoid intubation and mechanical ventilation in patients with acute exacerbated chronic obstructive pulmonary disease failing non-invasive ventilation. This concept has been shown to be effective in 56-90% of patients. Extracorporeal carbon dioxide removal has also been used in ventilated patients with hypercapnic respiratory failure to correct acidosis, unload respiratory muscle burden, and facilitate weaning. In patients suffering from terminal fibrosis awaiting lung transplantation, extracorporeal carbon dioxide removal is able to correct acidosis and enable spontaneous breathing during bridging. Keeping these patients awake, ambulatory, and breathing spontaneously is associated with favorable outcome. Complications: Complications of extracorporeal carbon dioxide removal are mostly associated with vascular access and deranged hemostasis leading to bleeding. Although the spectrum of complications may differ, no technology offers advantages with respect to rate and severity of complications. So called “high-extraction systems” working with higher blood flows and larger membranes may be more effective with respect to clinical goals.

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Effect of expiratory flow patterns on lung emptying

Journal of Applied Physiology ◽

10.1152/jappl.1963.18.1.47 ◽

1963 ◽

Vol 18 (1) ◽

pp. 47-50 ◽

Cited By ~ 9

Author(s):

A. C. Young ◽

C. J. Martin ◽

William R. Pace

Keyword(s):

Carbon Dioxide ◽

Flow Pattern ◽

Body Position ◽

Volume Ratio ◽

Flow Patterns ◽

High Flow ◽

Low Flow ◽

Flow Rates ◽

Single Breath ◽

Expiratory Flow

Differences in expired alveolar gas concentrations with changes in expiratory flow were studied in single-breath experiments using nitrogen and carbon dioxide meters. High flow rates preferentially emptied lung areas having low ventilation-to-volume ratios and high ventilation-to-perfusion ratios, whereas low flow rates preferentially emptied areas of high ventilation-to-volume and low ventilation-to-perfusion ratios. Selective emptying of different lung areas by varying the expiratory flow pattern was not affected by age, sex, or body position. A model of the lung is proposed to explain how ventilation-to-volume ratio differences can be seen at mouth level during constant slow, varying, and constantly increasing or decreasing expiratory flow. Submitted on May 4, 1962

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