scholarly journals Development of a biomimetic microfluidic oxygen transfer device

Lab on a Chip ◽  
2016 ◽  
Vol 16 (17) ◽  
pp. 3227-3234 ◽  
Author(s):  
A. A. Gimbel ◽  
E. Flores ◽  
A. Koo ◽  
G. García-Cardeña ◽  
J. T. Borenstein
Keyword(s):  
Gas Exchange ◽  
Oxygen Transfer ◽  
Gas Transfer ◽  
Blood Gas ◽  
Endothelial Lining ◽  
Assist Device ◽  
Blood Compartment ◽  
Exchange Properties ◽  
Transfer Device

A microfluidic respiratory assist device is demonstrated, with blood gas transfer as a function of the size and number of transfer layers demonstrated, along with anti-coagulation and gas exchange properties of a confluent endothelial lining of the blood compartment.

Conceptual and Design Features of a Practical, Clinically Effective Intravenous Mechanical Blood Oxygen/Carbon Dioxide Exchange Device (Ivox)

1989 ◽  
Vol 12 (6) ◽  
pp. 384-389 ◽  
Author(s):  
JD Mortensen ◽  
G. Berry
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Venous Blood ◽  
Vena Cava ◽  
Hollow Fibers ◽  
Carbon Dioxide Exchange ◽  
Gas Transfer ◽  
Blood Gas ◽  
Design Features ◽  
Planning Stage

Conceptual and design features of a new intravascular blood gas exchange device include: placing multiple, thin-walled microporous hollow fibers in an elongated arrangement with a small overall outside diameter; covering the outer surface of each microporous hollow fiber with an ultrathin continuous silicone coating; forming the hollow fibers into a configuration that produces disturbed flow of blood over the external surface of each fiber; placing the device in the subject's vena cava through a femoral or jugular venotomy; producing a flow of oxygen through the lumens of the hollow fibers, permitting exchange of oxygen and carbon dioxide between the venous blood outside and the gas inside the hollow fibers. Based on these principles, a practical, easily insertible, disposable, intravenacaval blood gas exchange device (IVOX) has been fabricated. Currently, devices with from 2,000 to 6,000 square centimeters of gas transfer surface area are being placed in the vena cavae of dogs and sheep for up to 7 days without altering the animal's hemodynamics, without producing serious hematologic sequelae, and with the capability of transferring in excess of 100 ml of oxygen and carbon dioxide to and from the venous blood of an intact, awake, standing animal. Clinical trials on human subjects with severe, acute, potentially reversible respiratory failure are in the planning stage.

scholarly journals Towards a Biohybrid Lung: Endothelial Cells Promote Oxygen Transfer through Gas Permeable Membranes

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Sarah Menzel ◽  
Nicole Finocchiaro ◽  
Christine Donay ◽  
Anja Lena Thiebes ◽  
Felix Hesselmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Gas Exchange ◽  
Oxygen Transfer ◽  
Umbilical Vein ◽  
Test Fluid ◽  
Gas Transfer ◽  
Extracorporeal Lung Support ◽  
Custom Made ◽  
Lung Endothelial Cells ◽  
Umbilical Vein Endothelial Cells

In patients with respiratory failure, extracorporeal lung support can ensure the vital gas exchange via gas permeable membranes but its application is restricted by limited long-term stability and hemocompatibility of the gas permeable membranes, which are in contact with the blood. Endothelial cells lining these membranes promise physiological hemocompatibility and should enable prolonged application. However, the endothelial cells increase the diffusion barrier of the blood-gas interface and thus affect gas transfer. In this study, we evaluated how the endothelial cells affect the gas exchange to optimize performance while maintaining an integral cell layer. Human umbilical vein endothelial cells were seeded on gas permeable cell culture membranes and cultivated in a custom-made bioreactor. Oxygen transfer rates of blank and endothelialized membranes in endothelial culture medium were determined. Cell morphology was assessed by microscopy and immunohistochemistry. Both setups provided oxygenation of the test fluid featuring small standard deviations of the measurements. Throughout the measuring range, the endothelial cells seem to promote gas transfer to a certain extent exceeding the blank membranes gas transfer performance by up to 120%. Although the underlying principles hereof still need to be clarified, the results represent a significant step towards the development of a biohybrid lung.

scholarly journals d-Cystine di(m)ethyl ester reverses the deleterious effects of morphine on ventilation and arterial blood gas chemistry while promoting antinociception

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin Gaston ◽  
Santhosh M. Baby ◽  
Walter J. May ◽  
Alex P. Young ◽  
Alan Grossfield ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Intracellular Signaling ◽  
Dimethyl Ester ◽  
Diethyl Ester ◽  
Blood Gas ◽  
Negative Effects ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Gas Chemistry ◽  
Ventilatory Drive

AbstractWe have identified thiolesters that reverse the negative effects of opioids on breathing without compromising antinociception. Here we report the effects of d-cystine diethyl ester (d-cystine diEE) or d-cystine dimethyl ester (d-cystine diME) on morphine-induced changes in ventilation, arterial-blood gas chemistry, A-a gradient (index of gas-exchange in the lungs) and antinociception in freely moving rats. Injection of morphine (10 mg/kg, IV) elicited negative effects on breathing (e.g., depression of tidal volume, minute ventilation, peak inspiratory flow, and inspiratory drive). Subsequent injection of d-cystine diEE (500 μmol/kg, IV) elicited an immediate and sustained reversal of these effects of morphine. Injection of morphine (10 mg/kg, IV) also elicited pronounced decreases in arterial blood pH, pO2 and sO2 accompanied by pronounced increases in pCO2 (all indicative of a decrease in ventilatory drive) and A-a gradient (mismatch in ventilation-perfusion in the lungs). These effects of morphine were reversed in an immediate and sustained fashion by d-cystine diME (500 μmol/kg, IV). Finally, the duration of morphine (5 and 10 mg/kg, IV) antinociception was augmented by d-cystine diEE. d-cystine diEE and d-cystine diME may be clinically useful agents that can effectively reverse the negative effects of morphine on breathing and gas-exchange in the lungs while promoting antinociception. Our study suggests that the d-cystine thiolesters are able to differentially modulate the intracellular signaling cascades that mediate morphine-induced ventilatory depression as opposed to those that mediate morphine-induced antinociception and sedation.

Eddy covariance flux measurements of momentum, heat and carbon dioxide in Hudson Bay at the onset of sea ice melt 

2021 ◽  
Author(s):  
Richard Sims ◽  
Brian Butterworth ◽  
Tim Papakyriakou ◽  
Mohamed Ahmed ◽  
Brent Else
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Open Water ◽  
The Arctic ◽  
Gas Transfer ◽  
Hudson Bay ◽  
Flux Measurements ◽  
Ice Fraction

<p>Remoteness and tough conditions have made the Arctic Ocean historically difficult to access; until recently this has resulted in an undersampling of trace gas and gas exchange measurements. The seasonal cycle of sea ice completely transforms the air sea interface and the dynamics of gas exchange. To make estimates of gas exchange in the presence of sea ice, sea ice fraction is frequently used to scale open water gas transfer parametrisations. It remains unclear whether this scaling is appropriate for all sea ice regions. Ship based eddy covariance measurements were made in Hudson Bay during the summer of 2018 from the icebreaker CCGS Amundsen. We will present fluxes of carbon dioxide (CO<sub>2</sub>), heat and momentum and will show how they change around the Hudson Bay polynya under varying sea ice conditions. We will explore how these fluxes change with wind speed and sea ice fraction. As freshwater stratification was encountered during the cruise, we will compare our measurements with other recent eddy covariance flux measurements made from icebreakers and also will compare our turbulent CO<sub>2 </sub>fluxes with bulk fluxes calculated using underway and surface bottle pCO<sub>2</sub> data. </p><p> </p>

Gas exchange in healthy rabbits during high-frequency oscillatory ventilation

1989 ◽  
Vol 66 (3) ◽  
pp. 1343-1351 ◽  
Author(s):  
B. R. Boynton ◽  
M. D. Hammond ◽  
J. J. Fredberg ◽  
B. G. Buckley ◽  
D. Villanueva ◽  
...  
Keyword(s):  
Gas Exchange ◽  
High Frequency ◽  
High Frequency Oscillatory Ventilation ◽  
Blood Gas ◽  
Mean Airway Pressure ◽  
Oscillatory Ventilation ◽  
Dead Space Volume ◽  
Alveolar Hypoventilation ◽  
High Frequency Oscillatory ◽  
Space Volume

We examined the effects of oscillatory frequency (f), tidal volume (VT), and mean airway pressure (Paw) on respiratory gas exchange during high-frequency oscillatory ventilation of healthy anesthetized rabbits. Frequencies from 3 to 30 Hz, VT from 0.4 to 2.0 ml/kg body wt (approximately 20–100% of dead space volume), and Paw from 5 to 20 cmH2O were studied. As expected, both arterial partial pressure of O2 and CO2 (PaO2 and PaCO2, respectively) were found to be related to f and VT. Changing Paw had little effect on blood gas tensions. Similar values of PaO2 and PaCO2 were obtained at many different combinations of f and VT. These relationships collapsed onto a single curve when blood gas tensions were plotted as functions of f multiplied by the square of VT (f. VT2). Simultaneous tracheal and alveolar gas samples showed that the gradient for PO2 and PCO2 increased as f. VT2 decreased, indicating alveolar hypoventilation. However, venous admixture also increased as f. VT2 decreased, suggesting that ventilation-perfusion inequality must also have increased.

scholarly journals Sea-to-air and diapycnal nitrous oxide fluxes in the eastern tropical North Atlantic Ocean

2012 ◽  
Vol 9 (3) ◽  
pp. 957-964 ◽  
Author(s):  
A. Kock ◽  
J. Schafstall ◽  
M. Dengler ◽  
P. Brandt ◽  
H. W. Bange
Keyword(s):  
Nitrous Oxide ◽  
Gas Exchange ◽  
Mixed Layer ◽  
North Atlantic Ocean ◽  
Gas Transfer ◽  
Potential Contribution ◽  
Transfer Velocity ◽  
N2o Production ◽  
Gas Transfer Velocity ◽  
Upwelled Water

Abstract. Sea-to-air and diapycnal fluxes of nitrous oxide (N2O) into the mixed layer were determined during three cruises to the upwelling region off Mauritania. Sea-to-air fluxes as well as diapycnal fluxes were elevated close to the shelf break, but elevated sea-to-air fluxes reached further offshore as a result of the offshore transport of upwelled water masses. To calculate a mixed layer budget for N2O we compared the regionally averaged sea-to-air and diapycnal fluxes and estimated the potential contribution of other processes, such as vertical advection and biological N2O production in the mixed layer. Using common parameterizations for the gas transfer velocity, the comparison of the average sea-to-air and diapycnal N2O fluxes indicated that the mean sea-to-air flux is about three to four times larger than the diapycnal flux. Neither vertical and horizontal advection nor biological production were found sufficient to close the mixed layer budget. Instead, the sea-to-air flux, calculated using a parameterization that takes into account the attenuating effect of surfactants on gas exchange, is in the same range as the diapycnal flux. From our observations we conclude that common parameterizations for the gas transfer velocity likely overestimate the air-sea gas exchange within highly productive upwelling zones.

Study on the Intravenous Lung Assist Device (ILAD) Using PZT Actuators and PVDF Sensors

2008 ◽  
Vol 381-382 ◽  
pp. 353-356
Author(s):  
Gi Beum Kim ◽  
S.J. Kim ◽  
Y.C. Lee ◽  
C.U. Hong ◽  
H.S. Kang ◽  
...  
Keyword(s):  
Transfer Rate ◽  
Semipermeable Membrane ◽  
Gas Transfer ◽  
Scaling Analysis ◽  
Membrane Oxygenator ◽  
Assist Device ◽  
Dimensionless Groups ◽  
Membrane Vibrations ◽  
Insight Into ◽  
Membrane Vibration

The purpose of this study was to investigate the effect of vibration device in gas transfer rate for usage as intravenous lung assist device. Specific attention was focused on the effect of membrane vibration. Quantitative experimental measurements were performed to evaluate the performance of the device, and to identify membrane vibration dependence on hemolysis. Scaling analysis was then used to infer the dimensionless groups that correlate the performance of a vibrated hollow tube membrane oxygenator. The experimental design and procedure are then given for a device for assessing the effectiveness of membrane vibrations. This ILAD is used to provide some insight into how wall vibrations might enhance the performance of an intravascular lung assist device. The time and the frequency response of PVDF sensor were investigated through various frequencies in the ILAD. In these devices, the flow of blood and the source of oxygen were separated by a semipermeable membrane allows oxygen to diffuse into and out of the f1uid, respectively. The results of experiments have shown vibrating ILAD performs effectively.

Gas exchange in nonperfused dog lungs

1981 ◽  
Vol 51 (5) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. W. Shepard ◽  
V. D. Minh ◽  
G. F. Dolan
Keyword(s):  
Gas Exchange ◽  
Minute Ventilation ◽  
Left Lung ◽  
Co2 Concentration ◽  
Gas Transfer ◽  
O2 Uptake ◽  
Tissue Metabolism ◽  
End Tidal

Gas exchange was studied under conditions of zero perfusion both in situ and in vitro. Six dogs, anesthetized with pentobarbital sodium, underwent surgical interruption of both pulmonary and bronchial circulations to the left lung. Despite the absence of perfusion, O2 uptake for the left lung ranged from 0.76 to 0.98 ml/min, whereas CO2 elimination greatly exceeded O2 uptake ranging from 1.68 to 4.34 ml/min. In addition, CO2 output was observed to vary directly with the level of minute ventilation (VE) and inversely with end-tidal CO2 concentration. To investigate the mechanisms responsible for these findings we studied 20 excised, ventilated, but nonperfused dog lungs to evaluate the relative roles of tissue metabolism and transpleural diffusion to gas exchange. The results obtained with these excised lungs under conditions of varying VE and extrapleural gas concentrations indicate that the high respiratory exchange ratios observed in situ can be explained by the greater rate with which CO2 diffuses through the pleura, and that reduced ventilation decreases total gas transfer by decreasing the transpleural partial pressure driving gradient. Our data further document that the concentration of CO2 in alveolar gas may differ significantly from that present in inspired gas under conditions of ventilation-perfusion ratio equal to infinity, and that tissue metabolism as well as transpleural diffusion contribute to gas exchange in nonperfused lung.

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