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Schaefer TC, Greive S, Mencl S, Heiland S, Kramer M, Möhlenbruch MA, Kleinschnitz C, Bendszus M, Vollherbst DF. Iatrogenic Air Embolisms During Endovascular Interventions: Impact of Origin and Number of Air Bubbles on Cerebral Infarctions. Clin Neuroradiol 2024; 34:135-145. [PMID: 37665351 PMCID: PMC10881616 DOI: 10.1007/s00062-023-01347-2] [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: 05/26/2023] [Accepted: 08/22/2023] [Indexed: 09/05/2023]
Abstract
PURPOSE Cerebral infarctions caused by air embolisms (AE) are a feared risk in endovascular procedures; however, the relevance and pathophysiology of these AEs is still largely unclear. The objective of this study was to investigate the impact of the origin (aorta, carotid artery or right atrium) and number of air bubbles on cerebral infarctions in an experimental in vivo model. METHODS In 20 rats 1200 or 2000 highly calibrated micro air bubbles (MAB) with a size of 85 µm were injected at the aortic valve (group Ao), into the common carotid artery (group CA) or into the right atrium (group RA) using a microcatheter via a transfemoral access, resembling endovascular interventions in humans. Magnetic resonance imaging (MRI) using a 9.4T system was performed 1 h after MAB injection followed by finalization. RESULTS The number (5.5 vs. 5.5 median) and embolic patterns of infarctions did not significantly differ between groups Ao and CA. The number of infarctions were significantly higher comparing 2000 and 1200 injected MABs (6 vs. 4.5; p < 0.001). The infarctions were significantly larger for group CA (median infarction volume: 0.41 mm3 vs. 0.19 mm3; p < 0.001). In group RA and in the control group no infarctions were detected. Histopathological analyses showed early signs of ischemic stroke. CONCLUSION Iatrogenic AEs originating at the ascending aorta cause a similar number and pattern of cerebral infarctions compared to those with origin at the carotid artery. These findings underline the relevance and potential risk of AE occurring during endovascular interventions at the aortic valve and ascending aorta.
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Affiliation(s)
- Tabea C Schaefer
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
- Clinic for small animals, Justus-Liebig-University Gießen, Gießen, Germany
| | - Svenja Greive
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Stine Mencl
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Medicine Essen, Essen, Germany
| | - Sabine Heiland
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Martin Kramer
- Clinic for small animals, Justus-Liebig-University Gießen, Gießen, Germany
| | - Markus A Möhlenbruch
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Christoph Kleinschnitz
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), University Medicine Essen, Essen, Germany
| | - Martin Bendszus
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Dominik F Vollherbst
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany.
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Yuan J, Li Z, Ma Q, Li J, Li Z, Zhao Y, Qin S, Shi X, Zhao L, Yang P, Luo G, Wang X, Teh KS, Jiang Z. Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers. MICROSYSTEMS & NANOENGINEERING 2023; 9:20. [PMID: 36844939 PMCID: PMC9946994 DOI: 10.1038/s41378-023-00491-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/06/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
Ultrasonic fluid bubble detection is important in industrial controls, aerospace systems and clinical medicine because it can prevent fatal mechanical failures and threats to life. However, current ultrasonic technologies for bubble detection are based on conventional bulk PZT-based transducers, which suffer from large size, high power consumption and poor integration with ICs and thus are unable to implement real-time and long-term monitoring in tight physical spaces, such as in extracorporeal membrane oxygenation (ECMO) systems and dialysis machines or hydraulic systems in aircraft. This work highlights the prospect of capacitive micromachined ultrasonic transducers (CMUTs) in the aforementioned application situations based on the mechanism of received voltage variation caused by bubble-induced acoustic energy attenuation. The corresponding theories are established and well validated using finite element simulations. The fluid bubbles inside a pipe with a diameter as small as 8 mm are successfully measured using our fabricated CMUT chips with a resonant frequency of 1.1 MHz. The received voltage variation increases significantly with increasing bubble radii in the range of 0.5-2.5 mm. Further studies show that other factors, such as bubble positions, flow velocities, fluid medium types, pipe thicknesses and diameters, have negligible effects on fluid bubble measurement, demonstrating the feasibility and robustness of the CMUT-based ultrasonic bubble detection technique.
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Affiliation(s)
- Jiawei Yuan
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Zhikang Li
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, 265503 Yantai, China
| | - Qi Ma
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Jie Li
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical and Electrical Engineering, Shaanxi University of Science and Technology, Xi’an, 710049 Xi’an, China
| | - Zixuan Li
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Yihe Zhao
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Shaohui Qin
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Xuan Shi
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Libo Zhao
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, 265503 Yantai, China
| | - Ping Yang
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, 265503 Yantai, China
| | - Guoxi Luo
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, 265503 Yantai, China
| | - Xiaozhang Wang
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Kwok Siong Teh
- School of Engineering, San Francisco State University, San Francisco, CA 94132 USA
| | - Zhuangde Jiang
- State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and Systems, Xi’an Jiaotong University, 710049 Xi’an, China
- School of Mechanical Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, 265503 Yantai, China
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Abstract
An air embolism is induced by intravascular bubbles that block the blood flow in vessels, which causes a high risk of pulmonary hypertension and myocardial and cerebral infarction. However, it is still unclear how a moving bubble is stopped in the blood flow to form an air embolism in small vessels. In this work, microfluidic experiments, in vivo and in vitro, are performed in small vessels, where bubbles are seen to deform and stop gradually in the flow. A clot is always found to originate at the tail of a moving bubble, which is attributed to the special flow field around the bubble. As the clot grows, it breaks the lubrication film between the bubble and the channel wall; thus, the friction force is increased to stop the bubble. This study illustrates the stopping process of elongated bubbles in small vessels and brings insight into the formation of air embolism.
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Puthettu M, Vandenberghe S, Demertzis S. Effect of cannulation site on emboli travel during cardiac surgery. J Cardiothorac Surg 2021; 16:181. [PMID: 34162399 PMCID: PMC8220729 DOI: 10.1186/s13019-021-01564-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/06/2021] [Indexed: 11/10/2022] Open
Abstract
Background During cardiac surgery, micro-air emboli regularly enter the blood stream and can cause cognitive impairment or stroke. It is not clearly understood whether the most threatening air emboli are generated by the heart-lung machine (HLM) or by the blood-air contact when opening the heart. We performed an in vitro study to assess, for the two sources, air emboli distribution in the arterial tree, especially in the brain region, during cardiac surgery with different cannulation sites. Methods A model of the arterial tree was 3D printed and included in a hydraulic circuit, divided such that flow going to the brain was separated from the rest of the circuit. Air micro-emboli were injected either in the HLM (“ECC Bubbles”) or in the mock left ventricle (“Heart Bubbles”) to simulate the two sources. Emboli distribution was measured with an ultrasonic bubble counter. Five repetitions were performed for each combination of injection site and cannulation site, where air bubble counts and volumes were recorded. Air bubbles were separated in three categories based on size. Results For both injection sites, it was possible to identify statistically significant differences between cannulation sites. For ECC Bubbles, axillary cannulation led to a higher amount of air bubbles in the brain with medium-sized bubbles. For Heart Bubbles, aortic cannulation showed a significantly bigger embolic load in the brain with large bubbles. Conclusions These preliminary in vitro findings showed that air embolic load in the brain may be dependent on the cannulation site, which deserves further in vivo exploration.
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Affiliation(s)
- Mira Puthettu
- Foundation for Cardiovascular Research and Education (FCRE), Cardiovascular Engineering, Istituto Cardiocentro Ticino, Via ai Söi 24, 6807, Torricella-Taverne, Switzerland.
| | - Stijn Vandenberghe
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland.,Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
| | - Stefanos Demertzis
- Department of Cardiac Surgery, Istituto Cardiocentro Ticino, Lugano, Switzerland.,Faculty of Biomedical Sciences, Università della Svizzera Italiana, Lugano, Switzerland
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Casoni D, Mirra A, Goepfert C, Petruccione I, Spadavecchia C. Iatrogenic cerebral arterial gas embolism from flushing of the arterial line in two calves. Acta Vet Scand 2018; 60:51. [PMID: 30189865 PMCID: PMC6127953 DOI: 10.1186/s13028-018-0405-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 08/25/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Measurement of invasive blood pressure as reflection of blood flow and tissue perfusion is often carried out in animals during general anesthesia. Intravascular cannulation offers the potential for gas to directly enter the circulation and lead to arterial gas embolism. Cerebral arterial gas embolism may cause a spectrum of adverse effects ranging from very mild symptoms to severe neurological injury and death. Although several experimental models of arterial gas embolism have been published, there are no known published reports of accidental iatrogenic cerebral arterial gas embolism from flushing of an arterial line in animals. CASE PRESENTATION A 7-day-old Red Holstein-Friesian calf (No. 1) and a 28-day-old Holstein-Friesian calf (No. 2) underwent hot iron disbudding and sham disbudding, respectively, under sedation and cornual nerve anesthesia. Invasive arterial blood pressure was measured throughout the procedure and at regular intervals during the day. Before disbudding, a sudden and severe increase of blood pressure was observed following flushing of the arterial line. Excitation, hyperextension of the limbs and rapid severe horizontal nystagmus appeared shortly thereafter. Over the following minutes, symptoms ameliorated and blood pressure normalized in both cases. Prompt diagnosis was missed in calf 1; supportive fluid therapy was provided. Severe deterioration of neurologic status occurred in the following 24 h and culminated with stupor. The calf was euthanized for ethical reasons and the histological examination revealed extensive cerebral injury. Treatment of calf 2 consisted of supportive fluid and oxygen therapy; furosemide (1 mg/kg IV) was injected twice. Calf 2 appeared clinically normal after 2 h and showed no neurologic sequelae on a 3-month-follow up period. CONCLUSIONS There are no known reports of cerebral arterial gas embolism following flushing of the auricular arterial line in calves. The injection of a small amount of air at high pressure in a peripheral artery may lead to a significant cerebral insult. The clinical presentation is non-specific and can favour misdiagnosis and delay of therapy.
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Inci K, Koutouzi G, Chernoray V, Jeppsson A, Nilsson H, Falkenberg M. Air bubbles are released by thoracic endograft deployment: An in vitro experimental study. SAGE Open Med 2016; 4:2050312116682130. [PMID: 27994872 PMCID: PMC5153025 DOI: 10.1177/2050312116682130] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/09/2016] [Indexed: 11/15/2022] Open
Abstract
Purpose: Embolic stroke is a dreaded complication of thoracic endovascular aortic repair. The prevailing theory about its cause is that particulate debris from atherosclerotic lesions in the aortic wall are dislodged by endovascular instruments and embolize to the brain. An alternative source of embolism might be air trapped in the endograft delivery system. The aim of this experimental study was to determine whether air is released during deployment of a thoracic endograft. Methods: In an experimental benchtop study, eight thoracic endografts (five Medtronic Valiant Thoracic and three Gore TAG) were deployed in a water-filled transparent container drained from air. Endografts were prepared and deployed according to their instructions for use. Deployment was filmed and the volume of air released was collected and measured in a calibrated syringe. Results: Air was released from all the endografts examined. Air volumes ranged from 0.1 to 0.3 mL for Medtronic Valiant Thoracic and from <0.025 to 0.04 mL for Gore TAG. The largest bubbles had a diameter of approximately 3 mm and came from the proximal end of the Medtronic Valiant device. Conclusion: Air bubbles are released from thoracic endografts during deployment. Air embolism may be an alternative cause of stroke during thoracic endovascular aortic repair.
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Affiliation(s)
- Kamuran Inci
- Department of Surgery, Varberg Hospital, Varberg, Sweden
| | - Giasemi Koutouzi
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Valery Chernoray
- Department of Applied Mechanics, Chalmers University of Technology, Gothenburg, Sweden
| | - Anders Jeppsson
- Department of Thoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Håkan Nilsson
- Department of Applied Mechanics, Chalmers University of Technology, Gothenburg, Sweden
| | - Mårten Falkenberg
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden
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Cheng CK, Chang TY, Liu CH, Chang CH, Huang KL, Chin SC, Wu HC, Chang YJ, Lee TH. Presence of Gyriform Air Predicts Unfavorable Outcome in Venous Catheter-Related Cerebral Air Embolism. J Stroke Cerebrovasc Dis 2015. [PMID: 26219843 DOI: 10.1016/j.jstrokecerebrovasdis.2015.04.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND This study aimed to investigate the clinical predictors of unfavorable prognosis in patients with venous catheter-related cerebral air embolism. METHODS An extensive review of English literature was performed to obtain reports on cerebral air embolism published between January 1982 and July 2014 through PubMed, Journal at Ovid, and Web of Science using the Mesh terms and keywords "cerebral air embolism" and "cerebral gas embolism." Reports not fulfilling the diagnosis of cerebral air embolism and iterant articles were excluded. Demographics, clinical manifestations, and imaging findings were recorded. The air distribution on initial brain computed tomography (CT) was recorded as gyriform air (GF), cavernous sinus bubble, venous sinus bubble, and parenchymal and subarachnoid bubble. The enrolled subjects were further divided into favorable and unfavorable outcome groups for analyses. RESULTS Of the 33 cases enrolled, 31 had documented follow-up outcomes, including 14 with favorable and 17 with unfavorable prognoses. Patients with unfavorable outcome had older onset age (67.5 ± 15.8 versus 46.7 ± 17.0 years, P < .001), higher frequency of GF on brain CT (58.8% versus 0%, P < .01), initial consciousness disturbance (100% versus 42.9%, P < .001), and hemiparesis (100% versus 42.9%, P < .001), but lower frequency of cardiopulmonary symptoms (5.9% versus 64.3%, P < .01). In patients with central venous catheter-related cerebral air embolism, the retrograde mechanism had a tendency for worse outcomes (43.8% versus 0%, P = .023). CONCLUSIONS In patients with venous catheter-related cerebral air embolism, the presence of GF on brain CT imaging, old age, initial conscious disturbance, and hemiparesis may predict unfavorable outcomes.
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Affiliation(s)
- Chih-Kuang Cheng
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ting-Yu Chang
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Hung Liu
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan; Division of Medical Education, Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
| | - Chien-Hung Chang
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuo-Lun Huang
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shy-Chyi Chin
- Department of Medical Imaging and Intervention, Linkou Medical Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Hsiu-Chuan Wu
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yeu-Jhy Chang
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsong-Hai Lee
- Stroke Center and Department of Neurology, Linkou Medical Center, Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
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Bothma P, Schlimp C. II. Retrograde cerebral venous gas embolism: are we missing too many cases? Br J Anaesth 2014; 112:401-4. [DOI: 10.1093/bja/aet433] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Severe cerebral arterial gas embolism can be fatal; what about cerebral venous gas embolism? Crit Care Med 2014; 42:e250-1. [PMID: 24534990 DOI: 10.1097/ccm.0000000000000086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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10
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Juenemann M, Yeniguen M, Schleicher N, Blumenstein J, Nedelmann M, Tschernatsch M, Bachmann G, Kaps M, Urbanek P, Schoenburg M, Gerriets T. Impact of bubble size in a rat model of cerebral air microembolization. J Cardiothorac Surg 2013; 8:198. [PMID: 24139539 PMCID: PMC4016598 DOI: 10.1186/1749-8090-8-198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 09/24/2013] [Indexed: 11/16/2022] Open
Abstract
Background Cerebral air microembolization (CAM) is a frequent side effect of diagnostic or therapeutic interventions. Besides reduction of the amount of bubbles, filter systems in the clinical setting may also lead to a dispersion of large gas bubbles and therefore to an increase of the gas–liquid-endothelium interface. We evaluated the production and application of different strictly defined bubble diameters in a rat model of CAM and assessed functional outcome and infarct volumes in relation to the bubble diameter. Methods Gas emboli of defined number and diameter were injected into the carotid artery of rats. Group I (n = 7) received 1800 air bubbles with a diameter of 45 μm, group II (n = 7) 40 bubbles of 160 μm, controls (n = 6) saline without gas bubbles; group I and II yielded the same total injection volume of air with 86 nl. Functional outcome was assessed at baseline, after 4 h and 24 h following cerebral MR imaging and infarct size calculation. Results Computer-aided evaluation of bubble diameters showed high constancy (group I: 45.83 μm ± 2.79; group II: 159 μm ± 1.26). Animals in group I and II suffered cerebral ischemia and clinical deterioration without significant difference. Infarct sizes did not differ significantly between the two groups (p = 0.931 u-test). Conclusions We present further development of a new method, which allows reliable and controlled CAM with different bubble diameters, producing neurological deficits due to unilateral cerebral damage. Our findings could not display a strong dependency of stroke frequency and severity on bubble diameter.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Tibo Gerriets
- Department of Neurology, Justus-Liebig-University Giessen, Giessen, Germany.
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11
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Hyperbaric oxygen does not improve cerebral function when started 2 or 4 hours after cerebral arterial gas embolism in swine. Crit Care Med 2013; 41:1719-27. [PMID: 23632435 DOI: 10.1097/ccm.0b013e31828a3e00] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Hyperbaric oxygenation is the accepted treatment for cerebral arterial gas embolism. Although earlier start of hyperbaric oxygenation is associated with better outcome, it is unknown how much delay can be tolerated before start of hyperbaric oxygenation. This study investigates the effect of hyperbaric oxygenation on cerebral function in swine when initiated 2 or 4 hours after cerebral arterial gas embolism. DESIGN Prospective interventional animal study. SETTING Surgical laboratory and hyperbaric chamber. SUBJECTS Twenty-two Landrace pigs. INTERVENTIONS Under general anesthesia, probes to measure intracranial pressure, brain oxygen tension (PbtO2), and brain microdialysis, and electrodes for electroencephalography were placed. The electroencephalogram (quantified using temporal brain symmetry index) was suppressed during 1 hour by repeated injection of air boluses through a catheter placed in the right ascending pharyngeal artery. Hyperbaric oxygenation was administered using U.S. Navy Treatment Table 6 after 2- or 4-hour delay. Control animals were maintained on an inspiratory oxygen fraction of 0.4. MEASUREMENTS AND MAIN RESULTS Intracranial pressure increased to a mean maximum of 19 mm Hg (SD, 4.5 mm Hg) due to the embolization procedure. Hyperbaric oxygenation significantly increased PbtO2 in both groups treated with hyperbaric oxygenation (mean maximum PbtO2, 390 torr; SD, 177 torr). There were no significant differences between groups with regard to temporal brain symmetry index (control vs 2-hr delay, p = 0.078; control vs 4-hr delay, p = 0.150), intracranial pressure, and microdialysis values. CONCLUSIONS We did not observe an effect of hyperbaric oxygenation on cerebral function after a delay of 2 or 4 hours. The injury caused in our model could be too severe for a single session of hyperbaric oxygenation to be effective. Our study should not change current hyperbaric oxygenation strategies for cerebral arterial gas embolism, but further research is necessary to elucidate our results. Whether less severe injury benefits from hyperbaric oxygenation should be investigated in models using smaller amounts of air and clinical outcome measures.
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12
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Hague JP, Banahan C, Chung EML. Modelling of impaired cerebral blood flow due to gaseous emboli. Phys Med Biol 2013; 58:4381-94. [PMID: 23743635 DOI: 10.1088/0031-9155/58/13/4381] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Bubbles introduced to the arterial circulation during invasive medical procedures can have devastating consequences for brain function but their effects are currently difficult to quantify. Here we present a Monte Carlo simulation investigating the impact of gas bubbles on cerebral blood flow. For the first time, this model includes realistic adhesion forces, bubble deformation, fluid dynamical considerations, and bubble dissolution. This allows investigation of the effects of buoyancy, solubility, and blood pressure on embolus clearance. Our results illustrate that blockages depend on several factors, including the number and size distribution of incident emboli, dissolution time and blood pressure. We found it essential to model the deformation of bubbles to avoid overestimation of arterial obstruction. Incorporation of buoyancy effects within our model slightly reduced the overall level of obstruction but did not decrease embolus clearance times. We found that higher blood pressures generate lower levels of obstruction and improve embolus clearance. Finally, we demonstrate the effects of gas solubility and discuss potential clinical applications of the model.
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Affiliation(s)
- J P Hague
- Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK.
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