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Stiers M, Vercauteren J, Schepens T, Mergeay M, Janssen L, Hoogmartens O, Neyrinck A, Marinus BG, Sabbe M. Design of a flow modulation device to facilitate individualized ventilation in a shared ventilator setup. J Clin Monit Comput 2024; 38:679-690. [PMID: 38557919 PMCID: PMC11164813 DOI: 10.1007/s10877-024-01138-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/08/2024] [Indexed: 04/04/2024]
Abstract
This study aims to resolve the unmet need for ventilator surge capacity by developing a prototype device that can alter patient-specific flow in a shared ventilator setup. The device is designed to deliver a predictable tidal volume (VT), requiring minimal additional monitoring and workload. The prototyped device was tested in an in vitro bench setup for its performance against the intended use and design criteria. The ventilation parameters: VT and airway pressures, and ventilation profiles: pressure, flow and volume were measured for different ventilator and device settings for a healthy and ARDS simulated lung pathology. We obtained VTs with a linear correlation with valve openings from 10 to 100% across set inspiratory pressures (IPs) of 20 to 30 cmH2O. Airway pressure varied with valve opening and lung elastance but did not exceed set IPs. Performance was consistent in both healthy and ARDS-simulated lung conditions. The ventilation profile diverged from traditional pressure-controlled profiles. We present the design a flow modulator to titrate VTs in a shared ventilator setup. Application of the flow modulator resulted in a characteristic flow profile that differs from pressure- or volume controlled ventilation. The development of the flow modulator enables further validation of the Individualized Shared Ventilation (ISV) technology with individualization of delivered VTs and the development of a clinical protocol facilitating its clinical use during a ventilator surge capacity problem.
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Affiliation(s)
- Michiel Stiers
- Department of Public Health and Primary Care, Research unit Emergency Medicine, KU Leuven, 3000, Leuven, Belgium.
- Department of Emergency Medicine, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Jan Vercauteren
- Department of Mechanical Engineering, Royal Military Academy, Renaissancelaan 30, Brussels, Belgium
| | - Tom Schepens
- Department of Intensive Care Medicine, Ghent University Hospital, C Heymanslaan 10, Ghent, Belgium
| | - Matthias Mergeay
- Department of Anesthesiology and Critical Care Medicine, St-Dimpna, J.-B. Stessensstraat 2, 2440, Geel, Belgium
| | - Luc Janssen
- Department of Anesthesiology and Critical Care Medicine, St-Dimpna, J.-B. Stessensstraat 2, 2440, Geel, Belgium
| | - Olivier Hoogmartens
- Department of Public Health and Primary Care, Research unit Emergency Medicine, KU Leuven, 3000, Leuven, Belgium
- Department of Emergency Medicine, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Arne Neyrinck
- Department of Cardiovascular Sciences, Research unit Anesthesiology and Algology, KU Leuven, 3000, Leuven, Belgium
- Department of Anesthesiology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Benoît G Marinus
- Department of Mechanical Engineering, Royal Military Academy, Renaissancelaan 30, Brussels, Belgium
| | - Marc Sabbe
- Department of Public Health and Primary Care, Research unit Emergency Medicine, KU Leuven, 3000, Leuven, Belgium
- Department of Emergency Medicine, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
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2
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McMahon JW, Doukas DJ, Hanuscin C, Quale J, Eason J, Asrat H, Silverberg M, Paladino L. Re-Evaluating Cross-Contamination: Additional Trials on Co-Ventilation. J Emerg Med 2024; 66:e477-e482. [PMID: 38433037 DOI: 10.1016/j.jemermed.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 09/02/2023] [Accepted: 10/01/2023] [Indexed: 03/05/2024]
Abstract
BACKGROUND Medical equipment can become scarce in disaster scenarios. Prior work has reported that four sheep could be ventilated together on a single ventilator. Others found that this maneuver is possible when needed, but no one has yet investigated whether cross-contamination occurs in co-ventilated individuals. OBJECTIVE Our goal was to investigate whether an infection could spread between co-ventilated individuals. METHODS Four 2-L anesthesia bags were connected to a sterilized ventilator circuit that used heat and moisture exchange filters and bacterial and viral filters, as would be expected in this dire scenario. Serratia marcescens was inoculated into "lung" no. 1. After running for 24 h, each lung and three additional points in the circuit were cultured to see whether S. marcescens had spread. These cultures were examined at 24 and 48 h to assess for cross-contamination. This entire procedure was performed three times. RESULTS S. marcescens was not found in lung no. 2, 3, or 4 or the three additional sites on the expiratory limb at 24 and 48 h in all three trials. CONCLUSIONS Cross-contamination does not occur within 24 h using the described ventilator circuit configuration.
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Affiliation(s)
- Jonathan W McMahon
- Department of Emergency Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York; Department of Internal Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - Donald J Doukas
- Department of Emergency Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York; Department of Internal Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - Christopher Hanuscin
- Department of Emergency Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - John Quale
- Department of Infectious Disease, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - Julie Eason
- Department of Respiratory Therapy, SUNY Downstate Health Sciences University, Brooklyn, New York
| | - Habtamu Asrat
- Department of Infectious Disease, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - Mark Silverberg
- Department of Emergency Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
| | - Lorenzo Paladino
- Department of Emergency Medicine, SUNY Downstate Health Sciences University and Kings County Hospital Center, Brooklyn, New York
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Zieliński K, Lisowska B, Siewruk K, Sady M, Ferenc K, Barwijuk M, Olszewski J, Anusz K, Jabłoński A, Gajewska M, Okrzeja P, Michnikowski M, Pijanowska DG, Pluta K, Remiszewska E, Darowski M, Zabielski R, Liebert A, Kramek-Romanowska K, Stecka A, Kozarski M, Pasledni R, Gajewski Z, Ładyżyński P. Automatic air volume control system for ventilation of two patients using a single ventilator: a large animal model study. Sci Rep 2022; 12:22591. [PMID: 36585425 PMCID: PMC9801355 DOI: 10.1038/s41598-022-26922-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/21/2022] [Indexed: 12/31/2022] Open
Abstract
The COVID-19 pandemic outbreak led to a global ventilator shortage. Hence, various strategies for using a single ventilator to support multiple patients have been considered. A device called Ventil previously validated for independent lung ventilation was used in this study to evaluate its usability for shared ventilation. We performed experiments with a total number of 16 animals. Eight pairs of pigs were ventilated by a ventilator or anesthetic machine and by Ventil for up to 27 h. In one experiment, 200 ml of saline was introduced to one subject's lungs to reduce their compliance. The experiments were analyzed in terms of arterial blood gases and respiratory parameters. In addition to the animal study, we performed a series of laboratory experiments with artificial lungs (ALs). The resistance and compliance of one AL (affected) were altered, while the tidal volume (TV) and peak pressure (Ppeak) in the second (unaffected) AL were analyzed. In addition, to assess the risk of transmission of pathogens between AL respiratory tracts, laboratory tests were performed using phantoms of virus particles. The physiological level of analyzed parameters in ventilated animals was maintained, except for CO2 tension, for which a permissive hypercapnia was indicated. Experiments did not lead to injuries in the animal's lungs except for one subject, as indicated by CT scan analysis. In laboratory experiments, changes in TV and Ppeak in the unaffected AL were less than 11%, except for 2 cases where the TV change was 20%. No cross-contamination was found in simulations of pathogen transmission. We conclude that ventilation using Ventil can be considered safe in patients undergoing deep sedation without spontaneous breathing efforts.
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Affiliation(s)
- Krzysztof Zieliński
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Barbara Lisowska
- Department of Anesthesiology and Intensive Medical Care, National Geriatrics, Rheumatology and Rehabilitation Institute, Warsaw, Poland
| | - Katarzyna Siewruk
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Maria Sady
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Karolina Ferenc
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Maciej Barwijuk
- grid.13339.3b0000000113287408I Department of Anesthesiology and Intensive Care, Medical University of Warsaw, Warsaw, Poland
| | - Jarosław Olszewski
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Krzysztof Anusz
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Artur Jabłoński
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Magdalena Gajewska
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13339.3b0000000113287408Medical University of Warsaw, Warsaw, Poland
| | - Piotr Okrzeja
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Marcin Michnikowski
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Dorota G. Pijanowska
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Krzysztof Pluta
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Elżbieta Remiszewska
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Marek Darowski
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Romuald Zabielski
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Adam Liebert
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Katarzyna Kramek-Romanowska
- grid.1035.70000000099214842Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland
| | - Anna Stecka
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Maciej Kozarski
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Raman Pasledni
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
| | - Zdzisław Gajewski
- grid.13276.310000 0001 1955 7966Veterinary Research Center, Center for Biomedical Research and Research Center for Regenerative Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland ,grid.13276.310000 0001 1955 7966Center of Translational Medicine, Warsaw University of Life Sciences – SGGW, Warsaw, Poland
| | - Piotr Ładyżyński
- grid.413454.30000 0001 1958 0162Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 4 Ks. Trojdena Str. 02109, Warsaw, Poland
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4
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Arellano DH, Tobar EA, Lazo MT, Rojas VA, Gajardo AIJ, Montecinos N, Regueira T, Cornejo RA. Assessment of a splitter for protective dual-patient ventilation in patients with acute respiratory distress syndrome. Br J Anaesth 2022; 128:e314-e317. [PMID: 35300864 PMCID: PMC8858692 DOI: 10.1016/j.bja.2022.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Daniel H Arellano
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile; Departamento de Kinesiología, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Eduardo A Tobar
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Marioli T Lazo
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Veronica A Rojas
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile
| | - Abraham I J Gajardo
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile
| | | | - Tomás Regueira
- Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Rodrigo A Cornejo
- Unidad de Pacientes Críticos, Departamento de Medicina, Hospital Clínico Universidad de Chile, Santiago, Chile; Center of Acute Respiratory Critical Illness (ARCI), Santiago, Chile.
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5
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Duke DJ, Clarke AL, Stephens AL, Djumas L, Gregory SD. A computational fluid dynamics assessment of 3D printed ventilator splitters and restrictors for differential multi-patient ventilation. 3D Print Med 2022; 8:2. [PMID: 34985624 PMCID: PMC8727976 DOI: 10.1186/s41205-021-00129-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 11/18/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The global pandemic of novel coronavirus (SARS-CoV-2) has led to global shortages of ventilators and accessories. One solution to this problem is to split ventilators between multiple patients, which poses the difficulty of treating two patients with dissimilar ventilation needs. A proposed solution to this problem is the use of 3D-printed flow splitters and restrictors. There is little data available on the reliability of such devices and how the use of different 3D printing methods might affect their performance. METHODS We performed flow resistance measurements on 30 different 3D-printed restrictor designs produced using a range of fused deposition modelling and stereolithography printers and materials, from consumer grade printers using polylactic acid filament to professional printers using surgical resin. We compared their performance to novel computational fluid dynamics models driven by empirical ventilator flow rate data. This indicates the ideal performance of a part that matches the computer model. RESULTS The 3D-printed restrictors varied considerably between printers and materials to a sufficient degree that would make them unsafe for clinical use without individual testing. This occurs because the interior surface of the restrictor is rough and has a reduced nominal average diameter when compared to the computer model. However, we have also shown that with careful calibration it is possible to tune the end-inspiratory (tidal) volume by titrating the inspiratory time on the ventilator. CONCLUSIONS Computer simulations of differential multi patient ventilation indicate that the use of 3D-printed flow splitters is viable. However, in situ testing indicates that using 3D printers to produce flow restricting orifices is not recommended, as the flow resistance can deviate significantly from expected values depending on the type of printer used. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- Daniel J. Duke
- Department of Mechanical & Aerospace Engineering, Monash University, Clayton, 3800 Victoria Australia
| | - Alexander L. Clarke
- Department of Anaesthesia, Royal Women’s Hospital, Parkville, 3052 Victoria Australia
- Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, 3052 Victoria Australia
| | - Andrew L. Stephens
- CardioRespiratory Engineering and Technology Laboratory (CREATElab), Baker Heart and Diabetes Institute, Melbourne, 3004 Victoria Australia
| | - Lee Djumas
- Department of Materials Engineering, Monash University, Clayton, 3800 Victoria Australia
| | - Shaun D. Gregory
- Department of Mechanical & Aerospace Engineering, Monash University, Clayton, 3800 Victoria Australia
- CardioRespiratory Engineering and Technology Laboratory (CREATElab), Baker Heart and Diabetes Institute, Melbourne, 3004 Victoria Australia
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6
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Raredon MSB, Fisher C, Heerdt PM, Schonberger RB, Nargi A, Nivison S, Fajardo E, Deshpande R, Akhtar S, Greaney AM, Belter J, Raredon T, Zinter J, McKee A, Michalski M, Baevova P, Niklason LE. Pressure-Regulated Ventilator Splitting for Disaster Relief: Design, Testing, and Clinical Experience. Anesth Analg 2021; 134:1094-1105. [PMID: 34928890 DOI: 10.1213/ane.0000000000005825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has revealed that even the best-resourced hospitals may lack sufficient ventilators to support patients under surge conditions. During a pandemic or mass trauma, an affordable, low-maintenance, off-the-shelf device that would allow health care teams to rapidly expand their ventilator capacity could prove lifesaving, but only if it can be safely integrated into a complex and rapidly changing clinical environment. Here, we define an approach to safe ventilator sharing that prioritizes predictable and independent care of patients sharing a ventilator. Subsequently, we detail the design and testing of a ventilator-splitting circuit that follows this approach and describe our clinical experience with this circuit during the COVID-19 pandemic. This circuit was able to provide individualized and titratable ventilatory support with individualized positive end-expiratory pressure (PEEP) to 2 critically ill patients at the same time, while insulating each patient from changes in the other's condition. We share insights from our experience using this technology in the intensive care unit and outline recommendations for future clinical applications.
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Affiliation(s)
- Micha Sam Brickman Raredon
- From the Department of Biomedical Engineering, Yale University, New Haven, Connecticut.,Medical Scientist Training Program
| | - Clark Fisher
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Paul M Heerdt
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | | | - Alyssa Nargi
- Division of Respiratory Care, Yale-New Haven Hospital, New Haven, Connecticut
| | - Steven Nivison
- Division of Respiratory Care, Yale-New Haven Hospital, New Haven, Connecticut
| | - Elaine Fajardo
- Division of Pulmonary, Critical Care, and Sleep Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Ranjit Deshpande
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Shamsuddin Akhtar
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Allison M Greaney
- From the Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Joseph Belter
- Center for Engineering Innovation and Design, Yale University, New Haven, Connecticut
| | | | - Joseph Zinter
- Center for Engineering Innovation and Design, Yale University, New Haven, Connecticut
| | - Andrew McKee
- Headland Strategy Group, San Francisco, California
| | | | - Pavlina Baevova
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Laura E Niklason
- From the Department of Biomedical Engineering, Yale University, New Haven, Connecticut.,Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
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7
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Sharing Mechanical Ventilator: In Vitro Evaluation of Circuit Cross-Flows and Patient Interactions. MEMBRANES 2021; 11:membranes11070547. [PMID: 34357197 PMCID: PMC8307053 DOI: 10.3390/membranes11070547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 12/31/2022]
Abstract
During the COVID-19 pandemic, a shortage of mechanical ventilators was reported and ventilator sharing between patients was proposed as an ultimate solution. Two lung simulators were ventilated by one anesthesia machine connected through two respiratory circuits and T-pieces. Five different combinations of compliances (30–50 mL × cmH2O−1) and resistances (5–20 cmH2O × L−1 × s−1) were tested. The ventilation setting was: pressure-controlled ventilation, positive end-expiratory pressure 15 cmH2O, inspiratory pressure 10 cmH2O, respiratory rate 20 bpm. Pressures and flows from all the circuit sections have been recorded and analyzed. Simulated patients with equal compliance and resistance received similar ventilation. Compliance reduction from 50 to 30 mL × cmH2O−1 decreased the tidal volume (VT) by 32% (418 ± 49 vs. 285 ± 17 mL). The resistance increase from 5 to 20 cmH2O × L−1 × s−1 decreased VT by 22% (425 ± 69 vs. 331 ± 51 mL). The maximal alveolar pressure was lower at higher compliance and resistance values and decreased linearly with the time constant (r² = 0.80, p < 0.001). The minimum alveolar pressure ranged from 15.5 ± 0.04 to 16.57 ± 0.04 cmH2O. Cross-flows between the simulated patients have been recorded in all the tested combinations, during both the inspiratory and expiratory phases. The simultaneous ventilation of two patients with one ventilator may be unable to match individual patient’s needs and has a high risk of cross-interference.
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8
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Sorg ME, Branson RD, Hatipoğlu U, Chatburn RL. Multiplex Ventilation: Solutions for Four Main Safety Problems. Respir Care 2021; 66:1074-1086. [PMID: 33906955 DOI: 10.4187/respcare.08749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The COVID-19 pandemic has led to an increased demand for mechanical ventilators and concerns of a ventilator shortage. Several groups have advocated for 1 ventilator to ventilate 2 or more patients in the event of such a shortage. However, differences in patient lung mechanics could make sharing a ventilator detrimental to both patients. Our previous study indicated failure to ventilate in 67% of simulations. The safety problems that must be solved include individual control of tidal volume (VT), individual measurement of VT, individualization of PEEP settings, and individual PEEP measurement. The purpose of this study was to evaluate potential solutions developed at our institution. METHODS Two separate lung simulators were ventilated with a modified multiplex circuit using pressure control ventilation. Parameters of the lung models used for simulations (resistance and compliance) were evidence-based from published studies. Individual circuit-modification devices were first evaluated for accuracy. Devices were an adjustable flow diverter valve, a prototype dual volume display, a PEEP valve, and a disposable PEEP display. Then the full modified multiplex circuit was assessed by ventilating 6 pairs of simulated patients with different lung models and attempting to equalize ventilation. Ventilation was considered equalized when VT and end-expiratory lung volume were within 10% for each simulation. RESULTS The adjustable flow diverter valve allowed volume adjustment to 1 patient without affecting the other. The average error of the dual volume display was -17%. The PEEP valves individualized PEEP, but the PEEP gauge error ranged from 17% to 41%. Using the multiplex circuit, ventilation was equalized regardless of differences in resistance or compliance, reversing the "failure modes" of our previous study. CONCLUSIONS The results of this simulation-based study indicate that devices for individual control and display of VT and PEEP are effective in extending the usability and potential patient safety of multiplex ventilation.
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Affiliation(s)
- Morgan E Sorg
- Cleveland Clinic, Cleveland, Ohio. Mr Branson is affiliated with the University of Cincinnati, Cincinnati, Ohio and is Editor-in-Chief of Respiratory Care.
| | - Richard D Branson
- Cleveland Clinic, Cleveland, Ohio. Mr Branson is affiliated with the University of Cincinnati, Cincinnati, Ohio and is Editor-in-Chief of Respiratory Care
| | - Umur Hatipoğlu
- Cleveland Clinic, Cleveland, Ohio. Mr Branson is affiliated with the University of Cincinnati, Cincinnati, Ohio and is Editor-in-Chief of Respiratory Care
| | - Robert L Chatburn
- Cleveland Clinic, Cleveland, Ohio. Mr Branson is affiliated with the University of Cincinnati, Cincinnati, Ohio and is Editor-in-Chief of Respiratory Care
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