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1
Zakhary, Bishoy, Jayne Sheldrake, and Vincent Pellegrino. "Extracorporeal membrane oxygenation and V/Q ratios: an ex vivo analysis of CO2 clearance within the Maquet Quadrox-iD oxygenator." Perfusion 35, no. 1_suppl (May 2020): 29–33. http://dx.doi.org/10.1177/0267659120906767.
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While hypercapnia is typically well treated with modern membrane oxygenators, there are cases where respiratory acidosis persists despite maximal extracorporeal membrane oxygenation support. To better understand the physiology of gas exchange within the membrane oxygenator, CO2 clearance within an adult Maquet Quadrox-iD oxygenator was evaluated at varying blood CO2 tensions and V/Q ratios in an ex vivo extracorporeal membrane oxygenation circuit. A closed blood-primed circuit incorporating two Maquet Quadrox-iD oxygenators in series was attached to a Maquet PLS Rotaflow pump. A varying blend of CO2 and air was connected to the first oxygenator to provide different levels of pre-oxygenator blood CO2 levels (PvCO2) to the second oxygenator. Varying sweep gas flows of 100% O2 were connected to the second oxygenator to provide different V/Q ratios. Exhaust CO2 was directly measured, and then VCO2 and oxygenator dead space fraction (VD/VT) were calculated. VCO2 increased with increasing gas flow rates with plateauing at V/Q ratios greater than 4.0. Exhaust CO2 increased with PvCO2 in a linear fashion with the slope of the line decreasing at high V/Q ratios. Oxygenator dead space fraction varied with V/Q ratio—at lower ratios, dead space fraction was 0.3-0.4 and rose to 0.8-0.9 at ratios greater than 4.0. Within the Maquet Quadrox-iD oxygenator, CO2 clearance is limited at high V/Q ratios and correlated with elevated oxygenator dead space fraction. These findings have important implications for patients requiring high levels of extracorporeal membrane oxygenation support.
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Ratnaningsih, Enny, Putu T. P. Aryanti, Nurul F. Himma, Anita K. Wardani, K. Khoiruddin, Grandprix T. M. Kadja, Nicholaus Prasetya, and I. Gede Wenten. "Membrane Oxygenator for Extracorporeal Blood Oxygenation." Journal of Engineering and Technological Sciences 53, no. 5 (October 4, 2021): 210502. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.5.2.
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Extracorporeal blood oxygenation has become an alternative to supply O2 and remove CO2 from the bloodstream, especially when mechanical ventilation provides insufficient oxygenation. The use of a membrane oxygenator offers the advantage of lower airway pressure than a mechanical ventilator to deliver oxygen to the patient’s blood. However, research and development are still needed to find appropriate membrane materials, module configuration, and to optimize hydrodynamic conditions for achieving high efficient gas transfer and excellent biocompatibility of the membrane oxygenator. This review aims to provide a comprehensive description of the basic principle of the membrane oxygenator and its development. It also discusses the role and challenges in the use of membrane oxygenators for extracorporeal oxygenation on respiratory and cardiac failure patients.
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Mellgren, K., M. Skogby, Å. Järnås, LG Friberg, H. Wadenvik, and G. Mellgren. "Platelet activation and degradation in an experimental extracorporeal system. A comparison between a silicone membrane and a hollow-fibre oxygenator." Perfusion 11, no. 5 (September 1996): 383–88. http://dx.doi.org/10.1177/026765919601100505.
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Blood platelets are rapidly activated in contact with biomaterials and, therefore, can be used as markers of the biocompatibility of various components in an extracorporeal system. In the present work, two different oxygenators, one membrane oxygenator (Avecor) and one hollow-fibre oxygenator ('Lilliput', Dideco) were compared. Complete in vitro extracorporeal membrane oxygenation circuits were perfused with fresh, heparinized human blood for 24 h. Eight experiments were performed with the hollow-fibre oxygenator and five experiments with the membrane oxygenator. Blood gases, electrolytes, glucose and haematocrit were kept within physiological limits. Platelet count, plasma concentration of β-thromboglobulin, platelet serotonin content, platelet membrane glycoprotein Ib and its degradation product glycocalicin, as well as plasma haemoglobin concentration were assayed. As regards most of these variables, significant differences in favour of the hollow- fibre oxygenator were observed.
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Hendrix, Rik H. J., Eva R. Kurniawati, Sanne F. C. Schins, Jos G. Maessen, and Patrick W. Weerwind. "Dynamic oxygenator blood volume during prolonged extracorporeal life support." PLOS ONE 17, no. 2 (February 2, 2022): e0263360. http://dx.doi.org/10.1371/journal.pone.0263360.
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Current methods for identification of oxygenator clotting during prolonged extracorporeal life support include visual inspection, evaluation of oxygenator resistance and oxygen exchange performance, and assessment of clotting-related laboratory parameters. However, these observations do not provide a quantitative assessment of oxygenator clot formation. By measuring changes in the dynamic oxygenator blood volume this study aimed to evaluate the relation to oxygenator resistance and oxygen transfer performance. Sixty-seven oxygenators were studied during adult extracorporeal life support. Oxygenator blood volume, oxygenator resistance, and oxygen transfer efficiency were monitored. Oxygenator blood volume decreased with increasing runtime (r = -0.462; p <0.001). There was a statistically significant, fair negative correlation between oxygenator blood volume and oxygenator resistance (r = -0.476; p<0.001) in all oxygenators, which became stronger analyzing only exchanged oxygenators (r = -0.680; p<0.001) and oxygenators with an oxygenator blood volume <187 mL (r = 0.831; p<0.001). No relevant correlation between oxygenator blood volume and O2 transfer was found. Oxygenator blood volume declined over time and was clearly associated with an increasing oxygenator resistance during prolonged extracorporeal life support, though O2 transfer was less affected.
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Philipp, Alois, Christoph Wiesenack, Renate Behr, Franz X. Schmid, and Dietrich E. Birnbaum. "High risk of intraoperative awareness during cardiopulmonary bypass with isoflurane administration via diffusion membrane oxygenators." Perfusion 17, no. 3 (May 2002): 175–78. http://dx.doi.org/10.1191/0267659102pf566oa.
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In cardiac surgery with the aid of extracorporeal circulation (ECC), inhalation anaesthetics can be administered via the oxygenator. Until the recent advent of a new type of diffusion membrane oxygenator, we routinely added the inhalation agent, isoflurane, to the gas flow of a micro-porous capillary membrane-type oxygenator. Applying this procedure to the diffusion-type oxygenators, the depth of anaesthesia appeared to be affected, which manifested itself through unusually high intraoperative perfusion pressures. This observation led to a prospective randomized study comprising 60 patients and two models of a microporous capillary membrane oxygenator, as well as two models of a diffusion membrane oxygenator. Simultaneous isoflurane concentration measurements at both the gas inlet and outlet ports of the oxygenators showed that, whereas in the microporous capillary-type oxygenators the isoflurane administered was reduced by about 50% during the passage of gas through the device, there was only a minimal transfer of isoflurane in the diffusion-type membrane oxygenators.
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Cies, Jeffrey J., Wayne S. Moore, Nadji Giliam, Tracy Low, Daniel Marino, Jillian Deacon, Adela Enache, and Arun Chopra. "Oxygenator impact on voriconazole in extracorporeal membrane oxygenation circuits." Perfusion 35, no. 6 (July 6, 2020): 529–33. http://dx.doi.org/10.1177/0267659120937906.
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Introduction: To determine the oxygenator impact on alterations of voriconazole in a contemporary neonatal/pediatric (1/4 inch) and adolescent/adult (3/8 inch) extracorporeal membrane oxygenation circuit including the Quadrox-i® oxygenator. Methods: Simulated closed-loop extracorporeal membrane oxygenation circuits (1/4 and 3/8 inch) were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. In addition, 1/4- and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of voriconazole was administered into the circuits, and serial pre- and post-oxygenator concentrations were obtained at 5 minutes, 1, 2, 3, 4, 5, 6, and 24 hour time points. Voriconazole was also maintained in a glass vial and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation Results: For the 1/4-inch circuit, there was an approximate mean of 64-67% voriconazole loss with the oxygenator in series and mean of 15-20% voriconazole loss without an oxygenator in series at 24 hours. For the 3/8-inch circuit, there was an approximate mean of 44-51% voriconazole loss with the oxygenator in series and a mean of 8-12% voriconazole loss without an oxygenator in series at 24 hours. The reference voriconazole concentrations remained relatively constant during the entire study period demonstrating that the drug loss in each size of the extracorporeal membrane oxygenation circuit with or without an oxygenator was not a result of spontaneous drug degradation. Conclusion: This ex vivo investigation demonstrated substantial voriconazole loss within an extracorporeal membrane oxygenation circuit with an oxygenator in series with both sizes of the Quadrox-i oxygenator at 24 hours and no significant voriconazole loss in the absence of an oxygenator. Further evaluations with multiple dose in vitro and in vivo investigations are needed before specific voriconazole dosing recommendations can be made for clinical application with extracorporeal membrane oxygenation.
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Pearson, Derek T., Michael P. Holden, Stefan J. Poslad, Alan Murray, and Philip S. Waterhouse. "A clinical evaluation of the performance characteristics of one membrane and five bubble oxygenators: gas transfer and gaseous microemboli production." Perfusion 1, no. 1 (January 1986): 15–27. http://dx.doi.org/10.1177/026765918600100103.
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The gas transfer characteristics and gaseous microemboli (GME) production of five different bubble oxygenators (Polystan Venotherm, Harvey H-1700, Bentley BIO-10, Gambro 10 and Shiley S-100A HED) and one membrane oxygenator (Cobe CML) have been assessed during standardized clinical perfusion for open-heart surgery in 60 adult patients. The perfusionist attempted to maintain physiological levels of PaCO 2 (5 ± 1 kPa) and PaO2 (12 ± 2 kPa). Only 3% of blood gas values were within the normal range in the Bentley BIO-10 group compared with 17% for the Gambro 10, 20% for the Shiley S-100A HED, 31% for the Polystan Venotherm, 33% for the Cobe CML and 36% for the Harvey H-1700. The number of GME detected in the arterial line was significantly lower in the Cobe CML membrane oxygenator when compared with any of the five different bubble oxygenators (p < 0·001). The Polystan Venotherm released significantly less GME (p < 0·02) than the other oxygenators and the Shiley S-100A HED released significantly more GME (p < 0·02) than the other oxygenators except the Gambro 10. Low gas-blood flow ratios were not necessarily associated with low GME levels and inadequate oxygenation. This study provides meaningful data on which to base the choice of oxygenator, for clinical perfusions.
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Pearson, D. T., and B. McArdle. "Haemocompatibility of membrane and bubble oxygenators." Perfusion 4, no. 1 (January 1989): 9–24. http://dx.doi.org/10.1177/026765918900400103.
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During clinical hypothermic cardiopulmonary bypass (CPB), the haemocompatibility of six groups of membrane oxygenators (Cobe CML2, Shiley M2000, Maxima, Bard HF4000, Bard HF5000, Capiox E has been studied in 60 patients having open-heart surgery. A standardized anaesthetic and perfusion protocol was used, during which the abilityof the perfusionist to achieve target blood gas values (PaO2 20kPa and PaCO2 5.3kPa: alpha-stat) using inline electrodes was assessed. Haemocompatibility was evaluated by measurement of platelet numbers and function, betathromboglobulin (BTG), plasma haemoglobin, complement (C3a des Arg) and white blood cell (WBC) count pre- and post-CPB. Platelet and WBC numbers were also measured every five minutes throughout CPB. All oxygenators allowed the perfusionist to control blood gases adequately to prescribed levels. There were only minor differences in the degree and pattern of platelet depletion, reduction in platelet aggregation, elevation of BTG and C3a des Arg observed between oxygenator groups, which did not appear to be influenced by membrane type (flat plate versus hollow fibre). The membrane oxygenator haematological data was amalgamated with that obtained in previous clinical studies using membrane and bubble oxygenators (Cobe CML, Polystan Venotherm, Harvey H 1700, Bentley BIO-10, Bentley 1 0B, Bentley 1 OPlus, Gambro 10 and Shiley S100A HED) in which a similar evaluation protocol was employed. Comparison of the percentage change in platelet count when the pre- and post-CPB values were compared, demonstrated statistically significantly less platelet depletion (p <0.001 ) in the membrane oxygenator groups (-0.2 ± 8.3%) when compared to the bubble oxygenator groups (-21.7 ± 8.7%). A significantly lower percentage rise in BTG was also observed in the membrane oxygenator group when compared to the bubble oxygenator groups (p <0.001 ). All oxygenator groups showed elevation of both WBC count and plasma haemoglobin with a nonspecific fall in platelet aggregation over the period of bypass but no significant differences could be found between the two types of oxygenator. Membrane oxygenators, when compared to bubble oxygenators, exhibit lower GME production and improved haemocompatibility and allow superior blood gas control. Membrane oxygenators manifestly must be the oxygenator type of choice for clinical CPB.
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Aittomäki, Juha. "Monitoring of CO2 exchange during cardiopulmonary bypass: the effect of oxygenator design on the applicability of capnometry." Perfusion 8, no. 4 (July 1993): 337–44. http://dx.doi.org/10.1177/026765919300800409.
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The correlation between pCO2 values in blood and in exhaust gas from the oxygenators was examined during cardiopulmonary bypass (CPB) using one bubble oxygenator and three membrane oxygenators. Forty-seven CPBs were performed, 17 with Compactflow® (Dideco, ltaly), 10 with Maxima® (Medtronic Inc., USA), 10 with Cobe CML®(Cobe Laboratories, USA) membrane oxygenators and 10 with Hi-Flex® (Dideco, Italy) bubble oxygenators. Blood samples were taken both from arterial and venous lines of the oxygenator. A capnometer was connected to the oxygenator gas exhaust port and CO2 fraction was measured at the time of drawing blood samples. CO2 pressure in the gas phase was calculated from the product of the CO2 fraction and water vapour- corrected barometric pressure. Blood gases were measured at 37°C and the pCO2 value was corrected to the temperature of the arterial line. The correlation between blood and exhaust gas pCO2 was good in all the oxygenators examined, ranging from 0.921 to 0.976. The standard error of estimate (SEE) was in the range of about ± 2 mmHg for all the oxygenators. The systematic error (slope and intercept of the correlation line) varied depending on the construction of the oxygenator, with countercurrent design having the best overall correspondence. Based on the results of this study it can be concluded that arterial or venous CO 2 pressure can be monitored with a capnometry device coupled to the oxygenator gas outlet port. The use of a 'target FCO2 line' or a calculator program is proposed in order to aid the perfusionist in adjusting the oxygenator gas flow to attain normocarbia during CPB.
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Walczak, Richard, D. Scott Lawson, David Kaemmer, Craig McRobb, Patty McDermott, Greg Smigla, Ian Shearer, Andrew Lodge, and James Jaggers. "Evaluation of a preprimed microporous hollow-fiber membrane for rapid response neonatal extracorporeal membrane oxygenation." Perfusion 20, no. 5 (September 2005): 269–75. http://dx.doi.org/10.1191/0267659105pf819oa.
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Delays in initiating extracorporeal membrane oxygenation (ECMO) in the critically ill pediatric patient may lead to adverse outcomes. Maintaining a primed ECMO circuit can considerably reduce the initiation time. The predominant concerns precluding this practice are a decrease in oxygenator efficiency due to the saturation of microporous hollow fibers and compromised sterility when the oxygenator has been primed for 30 days. For institutions using a hollow-fiber oxygenator for ECMO, there are no data reporting pre-primed hollow-fiber oxygenator viability. This study reports the efficiency of oxygen transfer and the sterility of the Carmeda Minimax Plus (Medtronic, Inc, Minneapolis, MN) oxygenator after being crystalloid primed for 30 days. A total of 10 Minimax Plus oxygenators were tested for oxygen transfer in a laboratory setting utilizing fresh whole bovine blood. The control group ( n=5) were tested immediately after priming. The test group ( n=5) were oxygenators primed for 30 days with crystalloid solution and left stagnant until tested. Prior to testing, all oxygenators were circulated for 5 min and samples drawn to test for circuit sterility. Venous inlet saturations were manipulated to achieve three levels of testing: venous saturation (SvO2) of 55% for an oxygen challenge, SvO2 of 65% to comply with AAMI standards, and SvO2 of 75% to assess oxygen transfer rates and peak PaO2 achievement. Blood flow for all tests was maintained at 2 L/min with 1:1 blood to gas flow ratio and 100% FiO2. Samples were drawn pre- and postoxygenator at 1- and 6-hour time intervals to compute actual oxygen transfer values. All cultures from the test group priming solution produced no microbial growth after 30 days of stagnant prime. Average oxygen transfer values (ml/O2/min) for the control group after 1 hour of continuous use were 130.1±15.5 (@55% SvO2), 113.7±10.4 (@65% SvO2),97.7±8.9 (@75% SvO2). After 6 hours, the average transfer values increased to 134.2±13.2 (@55% SvO2), 118.76±6.6 (@65% SvO2) and 98.9±8.3 (@75% SvO2). The average oxygen transfer values after 1 hour for oxygenators primed for 30 days were 114.9±10.0 (@55% SvO2), 112.4±8.2 (@65% SvO2) and 89.6±16.0 (@75% SvO2). After 6 hours of use, the average transfer values all decreased to 111.4±2.1 (@55% SvO2, p <0.05 versus control), 104.0±5.6 (@65% SvO2, p<0.05 versus control) and 88.4±3.2 (@75% SvO2, p<0.05 versus control). In conclusion, there was a decrease in the average oxygen transfer values for the test group after 6 hours versus the control. The modest loss of oxygen transfer ability observed can be considered acceptable due to the amount of surface area of the Minimax Plus oxygenator when used on a neonate, making it feasible to adopt the practice of prepriming the Minimax oxygenator for neonatal ECMO.
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Wiesenack, Christoph, Gunther Wiesner, Cornelius Keyl, Michael Gruber, Alois Philipp, Markus Ritzka, Christopher Prasser, and Kai Taeger. "In Vivo Uptake and Elimination of Isoflurane by Different Membrane Oxygenators during Cardiopulmonary Bypass." Anesthesiology 97, no. 1 (July 1, 2002): 133–38. http://dx.doi.org/10.1097/00000542-200207000-00019.
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Background Volatile anesthetics are frequently used during cardiopulmonary bypass (CPB) to maintain anesthesia. Uptake and elimination of the volatile agent are dependent on the composition of the oxygenator. This study was designed to evaluate whether the in vivo uptake and elimination of isoflurane differs between microporous membrane oxygenators containing a conventional polypropylene (PPL) membrane and oxygenators with a new poly-(4-methyl-1-pentene) (PMP) membrane measuring isoflurane concentrations in blood. Methods Twenty-four patients undergoing elective coronary bypass surgery with the aid of CPB were randomly allocated to one of four groups, using either one of two different PPL-membrane oxygenators for CPB or one of two different PMP-membrane oxygenators. During hypothermic CPB, 1% isoflurane in an oxygen-air mixture was added to the oxygenator gas inflow line (gas flow, 3 l/min) for 15 min. Isoflurane concentration was measured in blood and in exhaust gas at the outflow port of the oxygenator. Between-group comparisons were performed for the area under the curve (AUC) during uptake and elimination of the isoflurane blood concentrations, the maximum isoflurane blood concentration (C(max)), and the exhausted isoflurane concentration (F(E)). Results The uptake of isoflurane, expressed as AUC of isoflurane blood concentration and a function of F(E), was significantly reduced in PMP oxygenators compared to PPL oxygenators (P < 0.01). C(max) was between 8.5 and 13 times lower in the PMP-membrane oxygenator groups compared to the conventional PPL-membrane oxygenator groups (P < 0.01). Conclusions The uptake of isoflurane into blood via PMP oxygenators during CPB is severely limited. This should be taken into consideration in cases using such devices.
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Mehra, AP, A. Akins, A. Maisuria, and BE Glenville. "Air handling characteristics of five membrane oxygenators." Perfusion 9, no. 5 (September 1994): 357–62. http://dx.doi.org/10.1177/026765919400900508.
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This project looked at the potential of five different membrane oxygenators to allow passage of catastrophic quantities of air in a clinically simulated environment. All the oxygenators were set up in an identical circuit using heparinized human blood as the perfusate. The study was carried out at flow rates ranging from 1.0 to 6.0 I/min. The clinical situation of obstructed venous drainage was simulated by clamping the venous return line at each respective flow rate, while the initial level of blood in the open system hard shell venous reservoir was maintained at 600 ml. The time interval between the application of the clamp on the venous line and the first appearance of macroscopic air in the arterial line was recorded at each level of flow rate. A graph of time versus flow rate was plotted for each oxygenator type. At a flow rate of 6 I/min, the Safe II oxygenator took 20 seconds to allow passage of air after the venous line was clamped, while it took the Bentley Univox Oxygenator only 10 seconds. The Dideco oxygenator, which has a valve incorporated in its reservoir, did not, however, allow any air to be pumped forward at all. At low flow rates, some of the oxygenators offered protection against passage of air into the arterial line. Thus the Cobe oxygenator offered protection at flow rates of less than 2 I/min, the Safe II oxygenator at flow rates of up to 2.5 I/min and the Bard oxygenator at flow rates up to 3 I/min. This study has demonstrated the potential of membrane oxygenators to allow passage to clinical quantities of air into the arterial line. This study also has demonstrated that the top to bottom flow feature offers protection against passage of air at low flow rates only, while a simple valve is quite effective in preventing passage of air at a wide range of clinically relevant flow rates.
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Durila, Miroslav, Tomas Smetak, Pavel Hedvicak, and Jan Berousek. "Extracorporeal membrane oxygenation–induced fibrinolysis detected by rotational thromboelastometry and treated by oxygenator exchange." Perfusion 34, no. 4 (January 11, 2019): 330–33. http://dx.doi.org/10.1177/0267659118824218.
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Coagulopathy and bleeding is a frequent phenomenon in patients on extracorporeal membrane oxygenation. The cause may be multifactorial and it may change over time. We present a case when bleeding was caused by hyperfibrinolysis induced by oxygenator. The diagnosis was established by comparing thromboelastometry result from blood obtained before and after oxygenator. Hyperfibrinolysis and bleeding could be successfully treated merely by oxygenator exchange.
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Hendrix, Rik HJ, Alexander KS Yeung, Yuri M. Ganushchak, and Patrick W. Weerwind. "The effect of flow and pressure on the intraoxygenator flow path of different contemporary oxygenators: an in vitro trial." Perfusion 35, no. 7 (February 14, 2020): 658–63. http://dx.doi.org/10.1177/0267659119899883.
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Introduction: This study analyzed the effect of different flows and pressures on the intraoxygenator flow path in three contemporary oxygenators and its consequences for oxygen transfer efficiency. Methods: In an experimental setup, intraoxygenator flow path parameters were analyzed at post-oxygenator pressures of 150, 200, and 250 mm Hg and at flows ranging from 2 L/min to the oxygenators’ maximum permitted flow, with and without pulsatility. The oxygen gradient and the oxygen transfer per minute and per 100 mL blood were calculated using previously collected clinical data and compared with the flow path parameters. Results: Increasing pressure did not affect the flow path parameters, whereas pulsatile flow led to significantly increased dynamic oxygenator blood volumes. Increased flow resulted in decreased values of the flow path parameters in all oxygenators, indicating increased flow through short pathways in the oxygenator. In parallel, oxygen transfer/100 mL blood decreased in all oxygenators (average 2.5 ± 0.4 to 2.4 ± 0.3 mL/dL, p > 0.001) and the oxygen gradient increased from 229 ± 45 to 287 ± 29 mm Hg, p > 0.001, indicating decreased oxygen transfer efficiency. Oxygen transfer/min increased (101 ± 15 to 143 ± 20 mL/min/m2, p > 0.001), however, due to the increased flow through the oxygenator. Conclusion: Varying trans-membrane oxygenator pressures did not lead to changes in the intraoxygenator flow path, while an increased flow exhibited lower flow path parameters resulting in less efficient use of the gas exchange compartment. The latter was confirmed by a decrease in O2 transfer efficiency during higher blood flows.
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Fukuda, Makoto, Asako Tokumine, Kyohei Noda, and Kiyotaka Sakai. "Newly Developed Pediatric Membrane Oxygenator that Suppresses Excessive Pressure Drop in Cardiopulmonary Bypass and Extracorporeal Membrane Oxygenation (ECMO)." Membranes 10, no. 11 (November 21, 2020): 362. http://dx.doi.org/10.3390/membranes10110362.
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This article developes a pediatric membrane oxygenator that is compact, high performance, and highly safe. This novel experimental approach, which imaging the inside of a membrane oxygenator during fluid perfusion using high-power X-ray CT, identifies air and blood retention in the local part of a membrane oxygenator. The cause of excessive pressure drop in a membrane oxygenator, which has been the most serious dysfunction in cardiovascular surgery and extracorporeal membrane oxygenation (ECMO), is the local retention of blood and air inside the oxygenator. Our designed blood flow channel for a membrane oxygenator has a circular channel and minimizes the boundary between laminated parts. The pressure drop in the blood flow channel is reduced, and the maximum gas transfer rates are increased by using this pediatric membrane oxygenator, as compared with the conventional oxygenator. Furthermore, it would be possible to reduce the incidents, which have occurred clinically, due to excessive pressure drop in the blood flow channel of the membrane oxygenator. The membrane oxygenator is said to be the “last stronghold” for patients with COVID-19 receiving ECMO treatment. Accordingly, the specification of our prototype is promising for low weight and pediatric patients.
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Pearson, Derek T., Brian McArdle, Stefan J. Poslad, and Alan Murray. "A clinical evaluation of the performance characteristics of one membrane and five bubble oxygenators: haemocompatibility studies." Perfusion 1, no. 2 (July 1986): 81–98. http://dx.doi.org/10.1177/026765918600100203.
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The haemocompatibility of five different bubble oxygenators (Polystan venotherm, Harvey H-1700, Bentley BIO-10, Gambro 10 and Shiley S-100A HED) and one membrane oxygenator (Cobe CML) have been evaluated during standardized clinical perfusion for open-heart surgery in 48 adult patients. Control of arterial PO2 and PCO2 was an important feature of the evaluation protocol. Over the period of cardiopulmonary bypass (CPB) there was a marked difference in the mean percentage reduction in platelet count in the different oxygenator groups. Only 1% reduction in platelet count occurred with the Cobe CML membrane oxygenator group compared with, in the bubble oxygenator groups, 7% for the Gambro 10, 16% for the Harvey H-1700, 19% for the Shiley S-100A HED, 24% for the Bentley BIO-10 and 31% for the Polystan venotherm. The post bypass platelet count was significantly lower than the prebypass value in all oxygenator groups ( p < 0.05) except the Cobe CML and Gambro 10. The two oxygenator groups with the largest percentage reduction in platelet count (Polystan venotherm and Bentley BIO-1 0) demonstrated a significant reduction ( p < 0.05) in platelet aggregation over the period of bypass. Platelet depletion in the Harvey H-1700. Shiley S-100A HED, Bentley BIO-10 and Polystan venotherm oxygenators was associated with a significant fall ( p < 0.05) in mean platelet volume during the first 35 minutes of CPB due to the removal from the circulation of large, young, functionally more active platelets. Erythrocyte damage was minimal in all oxygenator groups and only a minor degree of leucopenia could be demonstrated during the first five minutes of CPB. Cardiotomy suction was not associated with significant changes in platelet numbers or platelet aggregation. When selecting the oxygenator for use in patients undergoing open-heart surgery, gas transfer characteristics and GME production together with the superior preservation of platelet numbers and function in the membrane oxygenator group and variable degree of platelet depletion and reduction in platelet aggregability demonstrated in the five bubble oxygenator groups, must be taken into account.
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Ündar, Akif, Marian C. Holland, Russel V. Howelton, Cherie K. Benson, Jose R. Ybarra, O. LaWayne Miller, Mario M. Rossbach, et al. "Testing neonate-infant membrane oxygenators with the University of Texas neonatal pulsatile cardiopulmonary bypass system in vitro." Perfusion 13, no. 5 (September 1998): 346–52. http://dx.doi.org/10.1177/026765919801300511.
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Neurologic complications are already well documented after cardiopulmonary bypass (CPB) procedures in neonates and infants. Physiologic pulsatile flow CPB systems may be the alternative to the currently used steady-flow CPB circuits. In addition to the pulsatile pump, a membrane oxygenator should be chosen carefully, because only a few membrane oxygenators are suitable for physiologic pulsatile flow. We have tested four different types of neonate-infant membrane oxygenators for physiologic pulsatility with The University of Texas neonate-infant pulsatile CPB system in vitro. Evaluation criteria were based on mean ejection time, extracorporeal circuit (ECC) pressure, and upstroke of d p/d t. The results suggested that the Capiox 308 hollow-fibre membrane oxygenator produced the best physiologic pulsatile waveform according to the ejection time, ECC pressure, and the upstroke of d p/d t. The Minimax Plus and Masterflo Infant hollow-fibre membrane oxygenators also produced adequate pulsatile flow. Only the Variable Prime Cobe Membrane Lung (VPCML) Plus flat-sheet membrane oxygenator failed to reach the criteria for physiologic pulsatility. Depending on the oxygenator used, the lowest priming volume of the infant CPB circuit was 415 ml and the highest 520 ml.
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von Segesser, Ludwig. "Determination of significant differences in performance of the Bentley BOS-CM 40 hollow fibre membrane oxygenator and the Polystan VT5000 venotherm bubble oxygenator." Perfusion 2, no. 4 (October 1987): 289–95. http://dx.doi.org/10.1177/026765918700200408.
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Ten mongrel dogs were connected to cardiopulmonary bypass by cavoaortic cannulation, classic roller pump and either Bentley BOS-CM 40 hollow fibre membrane oxygenator or Polystan VT5000 Venotherm bubble oxygenator for eight hours, with mean flow rate of 100 ml/kg min. Platelet counts (all values corrected by prebypass haematocrit) were significantly lower in the bubble oxygenator group after two hours of cardiopulmonary bypass (p < 0·01). Plasma haemoglobin production was significantly higher after two hours of cardiopulmonary bypass in the bubble oxygenator group (p < 0·01). Venous oxygen saturation (SvO2) was above 65% during the eight hours perfusion in the membrane oxygenator group. In the bubble oxygenator group, however, SvO2 was below 60% after six hours of cardiopulmonary bypass. After eight hours perfusion the difference in SvO2 between the two groups was significant (p < 0·05). Thus membrane oxygenators such as the Bentley BOS-CM 40 appear to be indicated in cardiopulmonary bypass of more than two hours duration.
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Fried, David W., Michael A. Wilgus, and Steven J. Weiss. "The proposed use of a 'screening test' to assess oxygenator performance." Perfusion 8, no. 4 (July 1993): 299–306. http://dx.doi.org/10.1177/026765919300800404.
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This study aimed to assess whether the use of the physiological shunt equation could (within the first five minutes of initiating CPB) serve as a 'screen' to differentiate normal and dysfunctional oxygenator performance. If dysfunction severe enough to require replacement was necessary, the normothermic patient could be weaned from CPB and replacement would be carried out under safe, controlled conditions. This technique would require postponing the induction of hypothermia (if used), aortic cross-clamping, and arresting the heart until after this screen was completed. This study demonstrates that a strong negative correlation exists between the degree of blood shunting and the membrane's O2 transfer performance (r = -0.874). This relation enables us to predict O 2 transfer performance when only the shunt fraction is known. Of the 41 oxygenators used in this study, 40 demonstrated normal, or below-normal, shunt fractions. Oxygen transfer performance at or above predicted levels would be anticipated for these oxygenators. One of the 41 oxygenators had mildly elevated shunt fractions, which we predicted would be associated with mild O2 transfer dysfunction. Based on the performance screen worksheet we created, replacement was not necessary since the oxygenator maintained high levels of O2 transfer in reserve despite its marginal performance dysfunction. Assessment of oxygenator performance dysfunction in this earliest phase of CPB would greatly reduce the incidence of emergency oxygenator replacement secondary to actual or perceived oxygenator failure later in the course of the procedure.
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Steinberg, Carl, and Robert Dragan. "Clinical experience with the Sorin Monolyth Oxygenator at high altitude." Perfusion 14, no. 1 (January 1999): 77–81. http://dx.doi.org/10.1177/026765919901400111.
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High altitude combined with low barometric pressure can present unique challenges during cardiopulmonary bypass (CPB), not only for the perfusionist, but also for the oxygenator. Manufacturers of cardiopulmonary devices have responded to the requests from the perfusion community with a variety of oxygenators which balance low priming volumes and low pressure drops against high gas transfer. This paper will feature the first author’s clinical studies using the Sorin Monolyth Oxygenator in a selected group of patients at an altitude of approximately 5200 feet and an average barometric pressure of 634 mmHg (sea level is 760 mmHg). A review of the 47 charts on patients requiring CPB and who met the selection criteria was performed retrospectively. To qualify for this study, the patient needed to weigh more than 91 kg. The data reviewed included type of surgery, age, weight, bypass time, crossclamp time, pump flows (l/min/m2), hematocrits pre- and post-CPB, and pressure drop across the membrane. The PaO2, PaCO2, FiO2 and sweep gas flow at hypothermia and normothermia were recorded. Data concerning oxygen transfer were obtained from the manufacturer’s report to the Food and Drug Administration. All patients had adequate blood gases while on CPB. We feel that the design of the Sorin Monolyth Oxygenator met our criteria for an oxygenator: low priming volume, low pressure drop, and sufficient gas transfer to provide safe oxygenation of all patients at high altitude.
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Ni, Lei, Yu Feng Zhang, and Hong Ming Zhao. "Microporous Polypropylene Hollow Fiber Membrane Application in Membrane Oxygenator Model." Applied Mechanics and Materials 633-634 (September 2014): 541–44. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.541.
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In order to test the performance of the resulting membrane oxygenator, a model was constructed to simulate the inner and extracorporeal gas exchange of the human body. The oxygenation capacity of the membrane oxygenator was studied using fresh bovine blood with added anticoagulants as the test medium. The oxygenation performance of the prepared membrane was equal to that of the commercial membrane. After six hours of operation, the oxygen saturation (SaO2) was above 95%, and the partial pressure of oxygen (PaO2) was over 13.5 kPa (100 mmHg). This model was constructed in accordance with the basic principles of extracorporeal circulation, and could be used to investigate the oxygenation performance of a membrane oxygenator, as well as to study the basic principles of extracorporeal circulation.
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Issitt, R., T. Cumberland, A. Clements, and J. Mulholland. "Clinical evaluation of the Admiral 1.35m2 hollow-fibre membrane oxygenator." Perfusion 23, no. 1 (January 2008): 33–38. http://dx.doi.org/10.1177/0267659108093880.
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This prospective study was designed to evaluate the fundamental clinical performance of a new, small surface area oxygenator. Data were collected from twenty patients undergoing first-time coronary artery bypass grafting using this device. This study focuses on how the reduction of surface area and prime volume affects the essential function of the oxygenator in terms of oxygenation efficiency, heat transference, membrane pressure drops, haemolysis and safety. Oxygenation efficiency was deemed to be well within acceptable margins, even at high flows, over a temperature range of 32-36°C. Heat-exchanger performance was assessed by recording the heater/chiller water temperature compared to retrospective data from a current standard oxygenator. Heater/chiller water temperatures were on average 0.3°C higher with the small surface oxygenator than the standard data. The air handling of the device was excellent and extremely safe. Haemolysis, measured as plasma free haemoglobin, did not increase during bypass (p>0.05). This new oxygenator offers a reduced surface area and priming volume while still ensuring an acceptable safety reserve and performance.
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Lamm, Wolfgang, Bernhard Nagler, Alexander Hermann, Oliver Robak, Peter Schellongowski, Nina Buchtele, Andja Bojic, et al. "Propofol-based sedation does not negatively influence oxygenator running time compared to midazolam in patients with extracorporeal membrane oxygenation." International Journal of Artificial Organs 42, no. 5 (February 28, 2019): 233–40. http://dx.doi.org/10.1177/0391398819833376.
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Objective: Patients on extracorporeal membrane oxygenation are frequently in need for sedation. Use of propofol has been associated with impaired oxygenator function due to adsorption to the membrane as well as lipid load. The aim of our retrospective analysis was to compare two different sedation regimens containing either propofol or midazolam with respect to oxygenator running time. Methods: Midazolam was used in 73 patients whereas propofol was used in 49 patients, respectively. In the propofol group, veno-arterial–extracorporeal membrane oxygenation was used predominantly (84%), while veno-venous–extracorporeal membrane oxygenation was used more often in the midazolam group (64%). Results: Oxygenator running time until first exchange was 7 days in both groups ( p = 0.759). No statistically significant differences could be observed between the subgroup of patients receiving lipid-free (n = 24) and lipid-containing (n = 31) parenteral nutrition, respectively. Laboratory parameters like triglycerides, free hemoglobin, fibrinogen, platelets, and activated partial thromboplastin time were not significantly different between both sedation regimens ( p = 0.462, p = 0.489, p = 0.960, p = 0.134, and p = 0.843) and were not associated with oxygenator running time. Conclusion: The use of propofol as sedative seems suitable in patients undergoing extracorporeal membrane oxygenation therapy.
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Gu, Y. J., P. W. Boonstra, C. Akkerman, H. Mungroop, I. Tigchelaar, and W. Van Oeveren. "Blood compatibility of two different types of membrane oxygenator during cardiopulmonary bypass in infants." International Journal of Artificial Organs 17, no. 10 (October 1994): 543–48. http://dx.doi.org/10.1177/039139889401701006.
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The contact of blood with the artificial extracorporeal circuit causes a systemic inflammatory response due to blood activation. In this study, we compared two different paediatric membrane oxygenators used for extracorporeal circulation: a hollow fibre membrane oxygenator (Dideco Masterflo D-701, n=10), and a flat sheet silicone membrane oxygenator (Avecor Kolobow 800-2A, n=10). Blood compatibility was indicated by measuring complement activation as well as leukocyte and platelet activation. In patients perfused with a flat sheet membrane oxygenator, concentrations of complement split products C3a were significantly increased 30 minutes after the start of bypass (p<0.01), whereas only a mild increase of C3a was found in patients perfused with a hollow fibre membrane oxygenator. Leukocyte and platelet counts dropped uniformly in both groups after the start of bypass mainly due to hemodilution. Activation of leukocytes and platelets identified by both plasma β-glucuronidase and β-thromboglobulin was similar in both groups. Infants perfused with a flat sheet membrane oxygenator received significantly more donor blood than those perfused with a hollow fibre oxygenator (p<0.05). These results indicate that when used during paediatric cardiopulmonary bypass, a flat sheet membrane oxygenator has a higher complement activity than a hollow fibre membrane oxygenator, which is probably due to the relatively larger blood-surface contacting area of the oxygenator.
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Fisher, A. R. "The incidence and cause of emergency oxygenator changeovers." Perfusion 14, no. 3 (May 1999): 207–12. http://dx.doi.org/10.1177/026765919901400309.
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Emergency oxygenator changeover presents as an important potential hazard during cardiopulmonary bypass. In order to assess the frequency and possible causes of this event a retrospective survey was conducted of cardiothoracic units in the UK and Ireland. The survey was sent to these units in 1993 to cover the period from 1990 to 1992 inclusive and again in 1997 to cover the period from 1994 to 1996 inclusive. The total number of procedures reported in 1993 was 68 937 (response of 63%), among which there were 17 emergency oxygenator changeovers representing an incidence of one for every 4055 cases. The use of aprotinin was associated with nine of these incidents. Two other incidents occurred due to leaking oxygenators. The total number of procedures reported in 1997 was 97 313 (response of 70%), among which there were 21 emergency oxygenator changeovers, representing an incidence of one for every 4634 cases. The use of aprotinin was only associated with two of these incidents while seven were due to the development of a high trans-oxygenator pressure gradient and six occurred due to leaking oxygenators.
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Wendel, Hans P., Albertus M. Scheule, Friedrich S. Eckstein, and Gerhard Ziemer. "Haemocompatibility of paediatric membrane oxygenators with heparin-coated surfaces." Perfusion 14, no. 1 (January 1999): 21–28. http://dx.doi.org/10.1177/026765919901400104.
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Extracorporeal circulation (ECC) in paediatric patients with heparin-coated oxygenation systems is rarely investigated. The objective of this study was to evaluate, preclinically, the haemocompatibility of paediatric membrane oxygenators with heparin-coated surfaces. We compared 16 paediatric membrane oxygenators (Minimax, Medtronic) in an in vitro heart-lung machine model with fresh human blood. Eight of these oxygenation systems had a covalent heparin coating (Carmeda bioactive surface). After 90 min simulated ECC, the heparin-coated systems showed significantly higher platelet count, lower platelet-factor 4 release, reduced contact activation (factor XIIa and kallikrein), and lower neutrophil elastase levels ( p < 0.05), compared to the noncoated oxygenator group. More biocompatible materials for paediatric operations may ameliorate the various postperfusion syndromes arising from ECC procedures, particularly unspecific inflammation, hyperfibrinolysis and blood loss.
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Dallefeld, Samantha H., Jennifer Sherwin, Kanecia O. Zimmerman, and Kevin M. Watt. "Dexmedetomidine extraction by the extracorporeal membrane oxygenation circuit: results from an in vitro study." Perfusion 35, no. 3 (August 21, 2019): 209–16. http://dx.doi.org/10.1177/0267659119868062.
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Background: Dexmedetomidine is a sedative administered to minimize distress and decrease the risk of life threatening complications in children supported with extracorporeal membrane oxygenation. The extracorporeal membrane oxygenation circuit can extract drug and decrease drug exposure, placing the patient at risk of therapeutic failure. Objective: To determine the extraction of dexmedetomidine by the extracorporeal membrane oxygenation circuit. Materials and methods: Dexmedetomidine was studied in three closed-loop circuit configurations to isolate the impact of the oxygenator, hemofilter, and tubing on circuit extraction. Each circuit was primed with human blood according to standard practice for Duke Children’s Hospital, and flow was set to 1 L/min. Dexmedetomidine was dosed to achieve a therapeutic concentration of ~600 pg/mL. Dexmedetomidine was added to a separate tube of blood to serve as a control and evaluate for natural drug degradation. Serial blood samples were collected over 24 hours and concentrations were quantified with a validated assay. Drug recovery was calculated at each time point. Results: Dexmedetomidine was highly extracted by the oxygenator evidenced by a mean recovery of 62-67% at 4 hours and 23-34% at 24 hours in circuits with an oxygenator in-line. In contrast, mean recovery with the oxygenator removed was 96% at 4 hours and 93% at 24 hours. Dexmedetomidine was stable over time with a mean recovery in the control samples of 102% at 24 hours. Conclusion: These results suggest dexmedetomidine is extracted by the oxygenator in the extracorporeal membrane oxygenation circuit which may result in decreased drug exposure in vivo.
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Palanzo, David A., Debra L. Zarro, Ralph M. Montesano, and Norman J. Manley. "Albumin in the cardiopulmonary bypass prime: how little is enough?" Perfusion 14, no. 3 (May 1999): 167–72. http://dx.doi.org/10.1177/026765919901400303.
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Previous studies have demonstrated high transoxygenator pressures with noncoated hollow-fiber membrane oxygenators. These reports have been associated with dramatic platelet count drops during cardiopulmonary bypass (CPB). It has also been shown that adding human albumin to the prime of the bypass circuit reduces, if not eliminates, these problems. This study was conducted to determine what is the smallest amount of albumin added to the prime that will still display its protective effects. Eighty patients undergoing nonemergency open-heart surgery were randomly divided into four groups. Groups I and II received the Sarns Turbo 440 oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Groups III and IV received the Medtronic Maxima-PRF oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Pre-CPB, on CPB (15-20 min after the initiation of bypass) and warming hemoglobin, hematocrit and platelet counts were drawn on all patients. Net platelet count drop, which accounted for hemodilutional effects, was calculated for all specimens and compared to previous results obtained from the test oxygenators without albumin in the prime. The net platelet count drops for the study groups were as follows: • Sarns oxygenator with no albumin in the prime = 11.8 ± 12.5%; • Sarns oxygenator with 0.0375 g of albumin/100 ml prime = -3.7 ± 10.8%; • Sarns oxygenator with 0.125 g of albumin/100 ml prime = -2.0 ± 12.6%; • Medtronic oxygenator with no albumin in the prime = 20.1 ± 14.5%; • Medtronic oxygenator with 0.0375 g albumin/100 ml prime = -6.9 ± 8.7%; and • Medtronic oxygenator with 0.125 g albumin/100 ml prime = -14.0 ± 12.4%. Our results illustrate that adding as little as 0.0375 g albumin/100 ml prime (3 ml of 25% solution/2000 ml of prime) to the pump prime illicits the beneficial effects of surface coating on platelet loss during CPB.
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Lonský, Vladimír, Jiří Manďák, Jaroslav Kubíček, Martin Volt, Egon Procházka, and Jan Dominik. "Use of Two Parallel Oxygenators in a Very Large Patient (2.76 m2) for an Acute “A” Dissecting Aortic Aneurysm Repair." Acta Medica (Hradec Kralove, Czech Republic) 48, no. 2 (2005): 95–98. http://dx.doi.org/10.14712/18059694.2018.39.
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The very large patient (weight 142 kg, height 197 cm, body surface 2.76 m2) was referred to acute operation with dissecting type A ascending aortic aneurysm. The calculated blood flow was 6.63 l/min. To anticipate potential difficulties with perfusion and oxygenation two oxygenators connected in parallel were incorporated into the circuit. Bentall procedure with ACB to the RCA was performed. The perfusion was uneventful. Bypass time was 259 minutes, cross – clamp time 141 minutes, circulatory arrest 7 minutes. The highest oxygenators gas flow was 2.6 l/min with maximum FiO2 0.42. The use of two in parallel connected oxygenators is a very effective, easy and safe method in such extreme perfusions, offering to the perfusionist a great reserve of oxygenator output.
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Wagner, D., D. Pasko, K. Phillips, J. Waldvogel, and G. Annich. "In vitro clearance of dexmedetomidine in extracorporeal membrane oxygenation." Perfusion 28, no. 1 (August 13, 2012): 40–46. http://dx.doi.org/10.1177/0267659112456894.
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Dexmedetomidine (DMET) is a useful agent for sedation, both alone and in combination with other agents, in critically ill patients, including those on extracorporeal membrane oxygenation (ECMO) therapy. The drug is a clonidine-like derivative with an 8-fold greater specificity for the alpha 2-receptor while maintaining respiratory and cardiovascular stability. An in vitro ECMO circuit was used to study the effects of both “new” and “old” membrane oxygenators on the clearance of dexmedetomidine over the course of 24 hours. Once primed, the circuit was dosed with 840 μg of dexmedetomidine for a final concentration of 0.9 μg/ml. Serial samples, both pre- and post-oxygenator, were taken at 5, 60, 360, and 1440 minutes. Concentrations of the drug were expressed as a percentage of the original concentration remaining at each time point, both for new and old circuits. The new circuits were run at a standard flow for 24 hours, after which time the circuit was considered old and re-dosed with dexmedetomidine and the trial repeated. Results show that dexmedetomidine losses occur early in the circuits and then continue to decline. Initial losses in the first hour were 11+-65% and 59-73% pre- and post-oxygenator in the new circuit and 36-50% and 42-72% in the old circuit. The clearance of the drug through the membrane oxygenator exhibits no statistical difference between pre and post or new and old circuits. Dexmedetomidine can be expected to exhibit concentration changes during ECMO therapy. This effect appears to be more related to adsorption to the polyvinyl chloride (PVC) tubing rather than the membrane oxygenator. Dosage adjustments during dexmedetomidine administration during ECMO therapy may be warranted in order to maintain adequate serum concentrations and, hence, the desired degree of sedation.*(Lack of equilibrium)
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Jirschik, Mario, Cornelius Keyl, and Friedhelm Beyersdorf. "A clinical comparison of bubble elimination in Quadrox and Polystan oxygenators." Perfusion 24, no. 6 (November 2009): 423–27. http://dx.doi.org/10.1177/0267659109358206.
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Background: Microbubbles generated during heart surgery on extracorporeal circulation have been implicated as a possible cause of postoperative neurocognitive dysfunction and negative outcome. The main sources of microbubbles in the extracorporeal circuit are air leaking from the venous cannulation site, air delivered by drug and volume administration, during the taking of blood samples, during hemofiltration, and by using vacuum-assisted venous drainage (VAVD). Membrane oxygenators, although not designed for the elimination of gaseous microbubbles, can eliminate much of this air. Aim of the study / hypothesis: The aim of this study was to test the hypothesis that the amount of microbubbles passing through the oxygenator varies depending on the oxygenator design. Methods: one hundred patients undergoing aortic valve replacement with cardiopulmonary bypass (CPB) were included in a retrospective clinical trial assessing the bubble elimination of the two oxygenators routinely used in our clinic. The oxygenators (Quadrox-i Adult / Polystan Safe Maxi) are manufactured with the same hollow-fiber material, but display different designs. Bubbles were detected by a two-channel ultrasound bubble counter. The probes were placed directly at the inlet and the outlet of the oxygenators. The filtration index was calculated by the bubble counter as a measure of the percentage reduction of bubble volume and number. Results: The Quadrox has a significantly higher filtration index (92.3% [89.7; 95.1], median [25th,75th percentile]) than the Polystan (74.9% [64.2;80.9], p<0.001), indicating the superior ability of the Quadrox to eliminate microbubbles. Conclusion: Our study demonstrates major differences in the capacity of bubble elimination of the oxygenators being investigated, possibly depending on oxygenator design.
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Ündar, Akif, Bingyang Ji, Branka Lukic, Conrad M. Zapanta, Allen R. Kunselman, John D. Reibson, Tigran Khalapyan, et al. "Comparison of hollow-fiber membrane oxygenators with different perfusion modes during normothermic and hypothermic CPB in a simulated neonatal model." Perfusion 21, no. 6 (November 2006): 381–90. http://dx.doi.org/10.1177/0267659106073996.
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Purpose: The objectives of this investigation were (1) to compare two hollow-fiber membrane oxygenators (Capiox Baby RX versus Lilliput 1-D901) in terms of pressure drops and surplus hemodynamic energy (SHE) during normothermic and hypothermic cardiopulmonary bypass (CPB) in a simulated neonatal model; and (2) to evaluate pulsatile and non-pulsatile perfusion modes for each oxygenator in terms of SHE levels. Methods: In a simulated patient, CPB was initiated at a constant pump flow rate of 500 mL/min. The circuit was primed with fresh bovine blood. After 5 min of normothermic CPB, the pseudo-patient was cooled down to 25°C for 10 min followed by 30 min of hypothermic CPB. The pseudo-patient then underwent 10 min of rewarming and 5 min of normothermic CPB. At each experimental site (pre- and post-oxygenator and pre-aortic cannula), SHE was calculated using the following formula {SHE (ergs/cm3) = 1332 [((ffpdt)/(ffdt))-mean arterial pressure]} (f = pump flow and p = pressure). A linear mixed-effects model that accounts for the correlation among repeated measurements was fit to the data to assess differences in SHE between oxygenators, pumps, and sites. Tukey’s multiple comparison procedure was used to adjust p-values for post-hoc pairwise comparisons. Results: The pressure drops in the Capiox group compared to the Lilliput group were significantly lower during hypothermic non-pulsatile (21.3∓0.5 versus 50.7∓0.9 mmHg, p B < 0.001) and pulsatile (22∓0.0 versus 53.3∓0.5 mmHg, p < 0.001) perfusion, respectively. Surplus hemodynamic energy levels were significantly higher in the pulsatile group compared to the non-pulsatile group, with Capiox (1655∓92 versus 10 008∓1370 ergs/cm3, p < 0.001) or Lilliput (1506∓112 versus 7531∓483 ergs/cm3, p < 0.001) oxygenators. During normothermic CPB, both oxygenators had patterns similar to those observed under hypothermic conditions. Conclusions: The Capiox oxygenator had a significantly lower pressure drop in both pulsatile and non-pulsatile perfusion modes. For each oxygenator, the SHE levels were significantly higher in the pulsatile mode.
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Subraveti, Sai Nikhil, V. Vinod Kumar, Harish Pothukuchi, P. S. T. Sai, and B. S. V. Patnaik. "Numerical investigation of membrane oxygenation using sub-channel analysis." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 12 (December 3, 2018): 2942–59. http://dx.doi.org/10.1108/hff-10-2017-0431.
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PurposeBetter membrane oxygenators need to be developed to enable efficient gas exchange between venous blood and air.Design/methodology/approachOptimal design and analysis of such devices are achieved through mathematical modeling tools such as computational fluid dynamics (CFD). In this study, a control volume-based one-dimensional (1D) sub-channel analysis code is developed to analyze the gas exchange between the hollow fiber bundle and the venous blood. DIANA computer code, which is popular with the thermal hydraulic analysis of sub-channels in nuclear reactors, was suitably modified to solve the conservation equations for the blood oxygenators. The gas exchange between the tube-side fluid and the shell-side venous blood is modeled by solving mass, momentum and species conservation equations.FindingsSimulations using sub-channel analysis are performed for the first time. As the DIANA-based approach is well known in rod bundle heat transfer, it is applied to membrane oxygenators. After detailed validations, the artificial membrane oxygenator is analyzed for different bundle sizes (L/W) and bundle porosity (epsilon) values, and oxygen saturation levels are predicted along the bundle. The present sub-channel analysis is found to be reasonably accurate and computationally efficient when compared to conventional CFD calculations.Research limitations/implicationsThis approach is promising and has far-reaching ramifications to connect and extend a well-known rod bundle heat transfer algorithm to a membrane oxygenator community. As a variety of devices need to be analyzed, simplified approaches will be attractive. Although the 1D nature of the simulations facilitates handling complexity, it cannot easily compete with expensive and detailed CFD calculations.Practical implicationsThis work has high practical value and impacts the design community directly. Detailed numerical simulations can be validated and benchmarked for future membrane oxygenator designs.Social implicationsFuture membrane oxygenators can be designed and analyzed easily and efficiently.Originality/valueThe DIANA algorithm is popularly used in sub-channel analysis codes in rod bundle heat transfer. This efficient approach is being implemented into membrane oxygenator community for the first time.
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Busek, Mathias, Stefan Grünzner, Tobias Steege, Udo Klotzbach, and Frank Sonntag. "Hypoxia-on-a-chip." Current Directions in Biomedical Engineering 2, no. 1 (September 1, 2016): 71–75. http://dx.doi.org/10.1515/cdbme-2016-0019.
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AbstractIn this work a microfluidic cell cultivation device for perfused hypoxia assays as well as a suitable controlling unit are presented. The device features active components like pumps for fluid actuation and valves for fluid direction as well as an oxygenator element to ensure a sufficient oxygen transfer. It consists of several individually structured layers which can be tailored specifically to the intended purpose. Because of its clearness, its mechanical strength and chemical resistance as well as its well-known biocompatibility polycarbonate was chosen to form the fluidic layers by thermal diffusion bonding. Several oxygen sensing spots are integrated into the device and monitored with fluorescence lifetime detection. Furthermore an oxygen regulator module is implemented into the controlling unit which is able to mix different process gases to achieve a controlled oxygenation. First experiments show that oxygenation/deoxygenation of the system is completed within several minutes when pure nitrogen or air is applied to the oxygenator. Lastly the oxygen input by the pneumatically driven micro pump was quantified by measuring the oxygen content before and after the oxygenator.
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Papanikolaou, Dimitra, Chris Savio, Mohammad A. Zafar, Leon Freudzon, Jinlin Wu, Mohamed Abdelbaky, Keith J. Pelletier, et al. "Left Atrial to Femoral Artery Full Cardiopulmonary Bypass: A Novel Technique for Descending and Thoracoabdominal Aortic Surgery." International Journal of Angiology 29, no. 01 (December 9, 2019): 019–26. http://dx.doi.org/10.1055/s-0039-3400479.
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AbstractLeft atrial-femoral artery (LA-FA) bypass with a centrifugal pump and no oxygenator is commonly used for descending and thoracoabdominal aortic (DTAA) operations, mitigating the deleterious effects of cross-clamping. We present our initial experience performing DTAA replacement under LA-FA (left-to-left) cardiopulmonary bypass (CPB) with an oxygenator. DTAA replacement under LA-FA bypass with an oxygenator was performed in 14 consecutive patients (CPB group). The pulmonary vein and femoral artery (or distal aorta) were cannulated and the full CPB machine were used, including oxygenator, roller pump, pump suckers, and kinetically enhanced drainage. The CPB group was compared with 50 consecutive patients who underwent DTAA replacement utilizing traditional LA-FA bypass without an oxygenator (LA-FA group). Perioperative data were collected and statistical analyses were performed. All CPB patients maintained superb cardiopulmonary stability. The pump sucker permitted immediate salvage and return of shed blood. Superb oxygenation was maintained at all times. High-dose full CPB heparin was reversed without difficulty. The CPB group required markedly fewer blood transfusions than the LA-FA group (2.21 vs. 5.88 units, p < 0.004). The 30-day mortality rate was 7.1% (n = 1) and there were no paraplegia cases in the CPB group versus 7 (14%) deaths and 3 (6%) paraplegia cases in the LA-FA group. Traditional LA-FA bypass without an oxygenator avoids high-dose heparin. In the present era, heparin reversal is more secure. Our experience finds that the novel application of LA-FA CPB with an oxygenator is safe and suggests improved hemodynamics (immediate return of shed blood) and a hemostatic advantage (avoidance of loss of coagulation factors in the cell saver).
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Abednejad, Atiye Sadat, Ghasem Amoabediny, and Azadeh Ghaee. "Surface Modification of Polypropylene Blood Oxygenator Membrane by Poly Ethylene Glycol Grafting." Advanced Materials Research 816-817 (September 2013): 459–63. http://dx.doi.org/10.4028/www.scientific.net/amr.816-817.459.
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Blood oxygenators play key role in Extra Corporeal Membrane Oxygenator (ECMO) system using for patients with acute respiratory problems, immature fetal and also in open heart surgery. Interaction between blood and blood oxygenator polymeric membrane surface lead to fouling phenomena which have negative effect on performance of this important medical device. A modification comprising surface activation, PEG immersing and PEG graft polymerization carried out to provide acceptable blood oxygenator performance, blood compatibility and reduction in heparin consumption at the same time. Modified membranes characterized by FTIR, contact angle measurements and Atomic Force Microscopy (AFM) analyses. Blood compatibility of modified surface was also detected by SEM images. Results clearly indicate that modifying membranes by PEG is an effective way for anti-fouling properties. Water contact angel reduction from 110ْ to 72ْ shows hydrophilicity enhancement, roughness increasing from 15 to 20 and blood compatibility improvement was investigated by SEM and AFM analysis results respectively.
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Fisher, Anthony Richard, Mya Baker, Mike Buffin, Patrick Campbell, Stephen Hansbro, Steven Kennington, Angela Lilley, and Michael Whitehorne. "Normal and abnormal trans-oxygenator pressure gradients during cardiopulmonary bypass." Perfusion 18, no. 1 (January 2003): 25–30. http://dx.doi.org/10.1191/0267659103pf635oa.
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A prospective study was conducted with the aims of 1) determining the normal trans-oxygenator pressure gradient characteristics for a range of oxygenators and 2) determining the characteristics, incidence and outcome of abnormally raised gradients. The trans-oxygenator pressure gradient was monitored in 3684 patients undergoing open-heart surgery in eight different hospitals. When the normal pressure gradient was measured during cardiopulmonary bypass in mmHg/L blood flow, a constant figure was obtained which was specific for each oxygenator. This gradient was abnormally raised in 16 cases (one in every 230 cases) and was raised to such an extent in three of these cases that an emergency oxygenator changeout was required (one in every 1228 cases). Among the 16 reported incidents, three different patterns of gradient changes occurred, suggesting the possibility that there were three different aetiologies. In nine of these incidents, the pressure gradient was normal immediately upon going on bypass, but rose rapidly to a plateau value, which then returned to the normal value within 40 minutes. In three cases, the pressure gradient was raised immediately upon going on bypass and then rapidly returned to the baseline. In one case, the pressure gradient was raised immediately upon going on bypass and stayed raised throughout the operation.
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Kuwana, Katsuyuki. "Membrane for Oxygenation and Development of Membrane Oxygenator." membrane 25, no. 3 (2000): 107–17. http://dx.doi.org/10.5360/membrane.25.107.
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Hamilton, Carole, Denise Marin, Frank Weinbrenner, Branka Engelhardt, Dow Rosenzweig, Ulrich Beck, Pavel Borisov, and Stephen Hohe. "A new method to measure oxygenator oxygen transfer performance during cardiopulmonary bypass: clinical testing using the Medtronic Fusion oxygenator." Perfusion 32, no. 2 (September 24, 2016): 133–40. http://dx.doi.org/10.1177/0267659116668400.
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Background: There is no acceptable method of testing oxygen transfer performance in membrane oxygenators quickly and easily during cardiopulmonary bypass. Pre-clinical testing of oxygenators is performed under controlled situations in the laboratory, correlating oxygen transfer to blood flow using 100% oxygen. This laboratory method cannot be used clinically as oxygen transfer values vary significantly at each blood flow and the FiO2 is not kept at 1. Therefore, a formula was developed which corrects the existing FiO2 to attain a PaO2 of 150 mmHg: the corrected FiO2 at 150 mmHg. In graph form, this corrected FiO2 (x-axis) is correlated to the patient’s oxygen consumption levels (y-axis), which determines the membrane oxygenator oxygen transfer performance. Methods: Blood gas and hemodynamic parameters taken during cardiopulmonary bypass using the Medtronic Fusion were used to calculate the oxygen consumption (inlet conditions to the oxygenator) and the corrected FiO2 for a PaO2 of 150 mmHg. Validation of the formula “FiO2-PaO2/(Pb−pH2O)+0.21” was carried out by plotting the calculated values on a graph using PaO2 values between 145 to 155 mmHg and then, using the corrected FiO2 for PaO2s outside of this range. Results: All trend-lines correlated significantly to confirm that the Medtronic Fusion had an extrapolated oxygen transfer of 419 milliliters O2/min at an FiO2 of 1 to achieve a PaO2 of 150 mmHg. Conclusions: Use of the corrected FiO2 correlated to the oxygen transfer conditions of the membrane oxygenator can easily be used on a routine basis, providing valuable information clinically. When used by the manufacturer under laboratory conditions, further clinically relevant data is provided in terms of FiO2 and resultant PaO2s instead of the present limitations using blood flow. In this way, a clinically justifiable method has been developed to finally establish a standard in testing membrane oxygenator performance.
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Liu, Anxin, Zhiquan Sun, Qier Liu, Ning Zhu, and Shigang Wang. "Pumping O2 with no N2: An Overview of Hollow Fiber Membrane Oxygenators with Integrated Arterial Filters." Current Topics in Medicinal Chemistry 20, no. 1 (January 22, 2020): 78–85. http://dx.doi.org/10.2174/1568026619666191210161013.
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The advancement of cardiac surgery benefits from the continual technological progress of cardiopulmonary bypass (CPB). Every improvement in the CPB technology requires further clinical and laboratory tests to prove its safety and effectiveness before it can be widely used in clinical practice. In order to reduce the priming volume and eliminate a separate arterial filter in the CPB circuit, several manufacturers developed novel hollow-fiber membrane oxygenators with integrated arterial filters (IAF). Clinical and experimental studies demonstrated that an oxygenator with IAF could reduce total priming volume, blood donor exposure and gaseous microemboli delivery to the patient. It can be easily set up and managed, simplifying the CPB circuit without sacrificing safety. An oxygenator with IAF is expected to be more beneficial to the patients with low body weight and when using a minimized extracorporeal circulation system. The aim of this review manuscript was to discuss briefly the concept of integration, the current oxygenators with IAF, and the in-vitro / in-vivo performance of the oxygenators with IAF.
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Krivitski, Nikolai, Gregory Galyanov, Deborah Cooper, Mariam M. Said, Oswaldo Rivera, Gerald T. Mikesell, and Khodayar Rais-Bahrami. "In vitro and in vivo assessment of oxygenator blood volume for the prediction of clot formation in an ECMO circuit (theory and validation)." Perfusion 33, no. 1_suppl (May 2018): 51–56. http://dx.doi.org/10.1177/0267659118765883.
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Introduction: Clotting is one of the major causes of mortality and morbidity during extracorporeal membrane oxygenation (ECMO). A large meta-analysis study suggests that 29% of patients require the oxygenator to be replaced during ECMO. As clots usually form in the oxygenator, the oxygenator blood volume (OXBV) decreases over time. The currently used pressure gradient as a predicator of clot formation is unreliable. Objective: The aim of this study was to develop and validate ultrasound dilution technology in a quantitative assessment of clotting, using measurements of OXBV. Methods: OXBV was measured using the ELSA monitor (Transonic Systems Inc., Ithaca, NY, USA) from the transit time of a saline bolus passing through the oxygenator as recorded by a sensor placed after the oxygenator. The accuracy and reproducibility (coefficient of variation [CV]) of OXBV measurement and its independence from ECMO flow was assessed in vitro in lambs and from a clinical data archive. Results: The in vitro accuracy compared with volumetric measurements of OXBV of 22-134 ml at flows of 300-700 ml/min was −0.8±6.6%. For an OXBV of 355 ml at flows of 1020-7000 ml/min, accuracy was −0.4±1.6%. In 88 animal OXBV measurements, the CV was 1.49±1.12%. For an OXBV of 153 (range 42-387 ml), clinical measurements at flow ranged from 210-5960 ml/min, with a CV of 3.20±2.44 %. Conclusion: Dilution technology has the ability to accurately and reproducibly assess the clotting process in the oxygenator. Larger studies are needed to establish guidelines for the prediction of imminent clotting and may help to avoid unnecessary circuit changes.
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Mueller, Xavier M., Hendrick T. Tevaearai, Monique Augstburger, Judith Horisberger, and L. K. von Segesser. "Experimental evaluation of the Dideco D903 Avant 1.7 hollow-fibre membrane oxygenator." Perfusion 13, no. 5 (September 1998): 353–59. http://dx.doi.org/10.1177/026765919801300512.
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Membrane oxygenators have now gained wide acceptance. A new hollow-fibre membrane oxygenator, the Dideco D903 Avant 1.7, with an optimized membrane surface (1.7 m2) and a wavy blood flow pattern, was tested for gas transfer and blood path resistance in a standardized setting with surviving animals. Three calves (mean body weight 63.29 ± 2.9 kg) were connected to cardiopulmonary bypass by jugular venous and carotid arterial cannulation, classic roller pump and the Dideco D903 oxygenator with a mean flow rate of 53 ± 0.1 ml/kg/min for 6 h. After this time, the animals were weaned from the CPB and thereafter from the ventilator. After 7 days, the animals were killed electively. Blood gas analysis was performed before bypass, after mixing (10 min) and then hourly for the 6 h of perfusion. Further samples were taken 30 min (spontaneous breathing) and 60 min after bypass (extubated). Physiological blood gas values could be maintained throughout perfusion in all animals. Mean arterial oxygen saturation varied between 99.3% and 99.7% for the arterial side of the oxygenator compared to 64.6% and 71% for the venous side. The highest mean pressure drop through the oxygenator was 54 mmHg. Postbypass blood gas analysis showed physiological values and no evidence of major lung trauma or pulmonary oedema in relation to the 6 h perfusion. The hollow-fibre membrane oxygenator, Dideco D903, offers excellent gas exchange capabilities and a low pressure drop under experimental conditions, despite reduced membrane surface area. The post mortem examination did not show any deleterious lesion.
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Yildirim, Funda, Dilsad Amanvermez Senarslan, Seyhmus Yersel, Barıs Bayram, Fatma Taneli, and Omer Tetik. "Systemic inflammatory response during cardiopulmonary bypass: Axial flow versus radial flow oxygenators." International Journal of Artificial Organs 45, no. 3 (January 31, 2022): 278–83. http://dx.doi.org/10.1177/03913988221075043.
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Background: The objective of this study was to investigate the inflammatory effects of different oxygenator flow pattern types in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Methods: We designed this randomized, single-blind, prospective study of patients with coronary artery disease. We compared the systemic inflammatory effects of oxygenators with two types of flow: axial flow and radial flow. Therefore, we divided the patients into two groups: 24 patients in the axial group and 28 patients in the radial group. IL-1, IL-6, IL-10, and TNF-α were examined for cytokine activation leading to a systemic inflammatory reaction. The samples were collected at three different time intervals: T1, T2, and T3 (T1 was taken before cardiopulmonary bypass, T2 just 1 h after CPB onset, and T3 was taken 24 h after the surgery). Results: There were no significant differences in demographic characteristics between the two groups. We observed that there were notably lower levels of humoral inflammatory response parameters (IL-1, IL-6, and TNF-α) in the radial flow oxygenator group than in the axial flow group at the specific sampling times. For IL-10, there was no significant difference for any time period. Conclusion: It might be advantageous to use a radial-flow-patterned oxygenator to limit the inflammatory response triggered by the oxygenators in cardiopulmonary bypass.
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Kurusz, Mark, Vincent R. Conti, and James F. Arens. "Oxygenator failure." Annals of Thoracic Surgery 49, no. 3 (March 1990): 511–12. http://dx.doi.org/10.1016/0003-4975(90)90283-c.
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Crowley, Jeffrey C., and James Brown. "Oxygenator failure." Annals of Thoracic Surgery 50, no. 5 (November 1990): 859. http://dx.doi.org/10.1016/0003-4975(90)90720-q.
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Meidert, Agnes S., Alexander Choukèr, Siegfried Praun, Gustav Schelling, and Michael E. Dolch. "Exhaled Breath and Oxygenator Sweep Gas Propionaldehyde in Acute Respiratory Distress Syndrome." Molecules 26, no. 1 (December 31, 2020): 145. http://dx.doi.org/10.3390/molecules26010145.
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Background: Oxidative stress-induced lipid peroxidation (LPO) due to neutrophil-derived reactive oxygen species plays a key role in the early stage of the acute respiratory distress syndrome (ARDS). Monitoring of oxidative stress in this patient population is of great interest, and, ideally, this can be done noninvasively. Recently, propionaldehyde, a volatile chemical compound (VOC) released during LPO, was identified in the breath of lung transplant recipients as a marker of oxidative stress. The aim of the present study was to identify if markers of oxidative stress appear in the oxygenator outflow gas of patients with severe ARDS treated with veno-venous extracorporeal membrane oxygenation (ECMO). Methods: The present study included patients with severe ARDS treated with veno-venous ECMO. Concentrations of acetone, isoprene, and propionaldehyde were measured in inspiratory air, exhaled breath, and oxygenator inflow and outflow gas at corresponding time points. Ion-molecule reaction mass spectrometry was used to measure VOCs in a sequential order within the first 24 h and on day three after ECMO initiation. Results: Nine patients (5 female, 4 male; age = 42.1 ± 12.2 year) with ARDS and already established ECMO therapy (pre-ECMO PaO2/FiO2 = 44.0 ± 11.5 mmHg) were included into analysis. VOCs appeared in comparable amounts in breath and oxygenator outflow gas (acetone: 838 (422–7632) vs. 1114 (501–4916) ppbv; isoprene: 53.7 (19.5–244) vs. 48.7 (37.9–108) ppbv; propionaldehyde: 53.7 (32.1–82.2) vs. 42.9 (24.8–122) ppbv). Concentrations of acetone, isoprene, and propionaldehyde in breath and oxygenator outflow gas showed a parallel course with time. Conclusions: Acetone, isoprene, and propionaldehyde appear in breath and oxygenator outflow gas in comparable amounts. This allows for the measurement of these VOCs in a critically ill patient population via the ECMO oxygenator outflow gas without the need of ventilator circuit manipulation.
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Santos, Jose, Else M. Vedula, Weixuan Lai, Brett C. Isenberg, Diana J. Lewis, Dan Lang, David Sutherland, et al. "Toward Development of a Higher Flow Rate Hemocompatible Biomimetic Microfluidic Blood Oxygenator." Micromachines 12, no. 8 (July 28, 2021): 888. http://dx.doi.org/10.3390/mi12080888.
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The recent emergence of microfluidic extracorporeal lung support technologies presents an opportunity to achieve high gas transfer efficiency and improved hemocompatibility relative to the current standard of care in extracorporeal membrane oxygenation (ECMO). However, a critical challenge in the field is the ability to scale these devices to clinically relevant blood flow rates, in part because the typically very low blood flow in a single layer of a microfluidic oxygenator device requires stacking of a logistically challenging number of layers. We have developed biomimetic microfluidic oxygenators for the past decade and report here on the development of a high-flow (30 mL/min) single-layer prototype, scalable to larger structures via stacking and assembly with blood distribution manifolds. Microfluidic oxygenators were designed with biomimetic in-layer blood distribution manifolds and arrays of parallel transfer channels, and were fabricated using high precision machined durable metal master molds and microreplication with silicone films, resulting in large area gas transfer devices. Oxygen transfer was evaluated by flowing 100% O2 at 100 mL/min and blood at 0–30 mL/min while monitoring increases in O2 partial pressures in the blood. This design resulted in an oxygen saturation increase from 65% to 95% at 20 mL/min and operation up to 30 mL/min in multiple devices, the highest value yet recorded in a single layer microfluidic device. In addition to evaluation of the device for blood oxygenation, a 6-h in vitro hemocompatibility test was conducted on devices (n = 5) at a 25 mL/min blood flow rate with heparinized swine donor blood against control circuits (n = 3). Initial hemocompatibility results indicate that this technology has the potential to benefit future applications in extracorporeal lung support technologies for acute lung injury.
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Fried, David W., Benjamin N. DeBenedetto, Joseph J. Leo, Gabriel J. Mattioni, Hasratt Mohamed, and Theodore L. Zombolas. "Clinical oxygen transfer performance of the Sorin Monolyth membrane oxygenator." Perfusion 9, no. 2 (March 1994): 119–26. http://dx.doi.org/10.1177/026765919400900206.
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Oxygen transfer performance of the Sorin Monolyth membrane oxygenator was evaluated. Similar to previous oxygen transfer performance studies conducted at this institution, our purpose was sixfold: (1) to construct an oxygen transfer slope (OTS); (2) to find the maximum extrapolated oxygen transfer; (3) to calculate the oxygenator performance index (OPI); (4) to generate a shunt fraction line; (5) to determine the percentage of predicted shunt (POPS); and (6) to compare the Monolyth's performance to several previously studied membrane oxygenators. From the OTS, the maximum extrapolated oxygen transfer was 346.4 ml O2/min. This absolute value was the lowest of the four oxygenators compared. When maximum oxygen transfer was compared relative to membrane surface area, the Monolyth ranked third (157.5 ml O2/Min). The Monolyth produced a relatively narrow range for the OPI (81.64-130.47%) and had the lowest standard deviation (SD) in this group. The Monolyth exhibited higher shunt fractions over the range of clinical blood flows when compared to our three previously studied oxygenators. The range of POPS values (71.65-128.77%) was relatively narrow and the SD was the lowest of the four. We concluded from our evaluation that the Monolyth had relatively low top end oxygen transfer capabilities, but provided very consistent and predictable oxygen transfer performance.
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Bellancini, Michele, Laura Cercenelli, Stefano Severi, Guido Comai, and Emanuela Marcelli. "Development of a CO2 Sensor for Extracorporeal Life Support Applications." Sensors 20, no. 13 (June 27, 2020): 3613. http://dx.doi.org/10.3390/s20133613.
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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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Bernard, Philip, Sean Skinner, Prasad Bhandary, Ana Ruzic, Matthew Bacon, Hubert Ballard, and John Daniel. "Hollow Fiber Oxygenator Composition Has a Significant Impact on Failure Rates in Neonates on Extracorporeal Membrane Oxygenation: A Retrospective Analysis." Journal of Pediatric Intensive Care 07, no. 01 (March 7, 2017): 007–13. http://dx.doi.org/10.1055/s-0037-1599150.
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AbstractIn extracorporeal life support (ECLS), there are two main types of oxygenators in clinical use for neonates: polymethylpentene (PMP) hollow fiber and polypropylene (PP) hollow fiber. A retrospective study was performed on neonates (n = 44) who had undergone ECLS for noncardiac indications from 2009 to 2015. Between the two groups (PMP n = 21, PP n = 23), the PP oxygenators failed 91% of the time, whereas the PMP oxygenators failed 43% of the time (p < 0.05). Analysis suggests PMP oxygenators are less prone to failure than PP oxygenators, and they require fewer number of oxygenator changes during a neonatal ECLS.