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Omlor AJ, Caspari S, Omlor LS, Jungmann AM, Krawczyk M, Schmoll N, Mang S, Seiler F, Muellenbach RM, Bals R, Lepper PM. Comparison of Serial and Parallel Connections of Membrane Lungs against Refractory Hypoxemia in a Mock Circuit. MEMBRANES 2023; 13:809. [PMID: 37887981 PMCID: PMC10608735 DOI: 10.3390/membranes13100809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 09/13/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023]
Abstract
Extracorporeal membrane oxygenation (ECMO) is an important rescue therapy method for the treatment of severe hypoxic lung injury. In some cases, oxygen saturation and oxygen partial pressure in the arterial blood are low despite ECMO therapy. There are case reports in which patients with such instances of refractory hypoxemia received a second membrane lung, either in series or in parallel, to overcome the hypoxemia. It remains unclear whether the parallel or serial connection is more effective. Therefore, we used an improved version of our full-flow ECMO mock circuit to test this. The measurements were performed under conditions in which the membrane lungs were unable to completely oxygenate the blood. As a result, only the photometric pre- and post-oxygenator saturations, blood flow and hemoglobin concentration were required for the calculation of oxygen transfer rates. The results showed that for a pre-oxygenator saturation of 45% and a total blood flow of 10 L/min, the serial connection of two identical 5 L rated oxygenators is 17% more effective in terms of oxygen transfer than the parallel connection. Although the idea of using a second membrane lung if refractory hypoxia occurs is intriguing from a physiological point of view, due to the invasiveness of the solution, further investigations are needed before this should be used in a wider clinical setting.
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Affiliation(s)
- Albert J. Omlor
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Stefan Caspari
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Leonie S. Omlor
- Department of Anaesthesiology and Critical Care, University Hospital of Saarland, 66424 Homburg, Germany
| | - Anna M. Jungmann
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Marcin Krawczyk
- Department of Internal Medicine II, University Hospital of Saarland, 66424 Homburg, Germany
- Laboratory of Metabolic Liver Diseases, Department of General, Transplant and Liver Surgery, Centre for Preclinical Research, Medical University of Warsaw, 02091 Warsaw, Poland
| | - Nicole Schmoll
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Sebastian Mang
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Frederik Seiler
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
| | - Ralf M. Muellenbach
- Department of Anaesthesiology and Critical Care, Campus Kassel of the University of Southampton, 34125 Kassel, Germany
| | - Robert Bals
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Philipp M. Lepper
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany
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Caspari S, Schwärzel LS, Jungmann AM, Schmoll N, Seiler F, Muellenbach RM, Krawczyk M, Dinh QT, Bals R, Lepper PM, Omlor AJ. A Novel Mock Circuit to Test Full-Flow Extracorporeal Membrane Oxygenation. MEMBRANES 2022; 12:membranes12050493. [PMID: 35629818 PMCID: PMC9147719 DOI: 10.3390/membranes12050493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 02/04/2023]
Abstract
Extracorporeal membrane oxygenation (ECMO) has become an important therapeutic approach in the COVID-19 pandemic. The development and research in this field strongly relies on animal models; however, efforts are being made to find alternatives. In this work, we present a new mock circuit for ECMO that allows measurements of the oxygen transfer rate of a membrane lung at full ECMO blood flow. The mock utilizes a large reservoir of heparinized porcine blood to measure the oxygen transfer rate of the membrane lung in a single passage. The oxygen transfer rate is calculated from blood flow, hemoglobin value, venous saturation, and post-membrane arterial oxygen pressure. Before the next measuring sequence, the blood is regenerated to a venous condition with a sweep gas of nitrogen and carbon dioxide. The presented mock was applied to investigate the effect of a recirculation loop on the oxygen transfer rate of an ECMO setup. The recirculation loop caused a significant increase in post-membrane arterial oxygen pressure (paO2). The effect was strongest for the highest recirculation flow. This was attributed to a smaller boundary layer on gas fibers due to the increased blood velocity. However, the increase in paO2 did not translate to significant increases in the oxygen transfer rate because of the minor significance of physically dissolved oxygen for gas transfer. In conclusion, our results regarding a new ECMO mock setup demonstrate that recirculation loops can improve ECMO performance, but not enough to be clinically relevant.
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Affiliation(s)
- Stefan Caspari
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Leonie S. Schwärzel
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Anna M. Jungmann
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Nicole Schmoll
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Frederik Seiler
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Ralf M. Muellenbach
- Department of Anaesthesiology and Critical Care, Campus Kassel of the University of Southampton, 34125 Kassel, Germany;
| | - Marcin Krawczyk
- Department of Internal Medicine II, University Hospital of Saarland, 66424 Homburg, Germany;
- Laboratory of Metabolic Liver Diseases, Department of General, Transplant and Liver Surgery, Centre for Preclinical Research, Medical University of Warsaw, 02091 Warsaw, Poland
| | - Quoc Thai Dinh
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Robert Bals
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
| | - Philipp M. Lepper
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
- Correspondence:
| | - Albert J. Omlor
- Department of Internal Medicine V—Pneumology, Allergology and Intensive Care Medicine, University Hospital of Saarland, 66424 Homburg, Germany; (S.C.); (L.S.S.); (A.M.J.); (N.S.); (F.S.); (Q.T.D.); (R.B.); (A.J.O.)
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