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Marklund N. Response to Nordström CH, "Rapid Selective Brain Cooling with PolarCap ®-A Commercial Delusion?" (doi: 10.1089/neu.2022.0456). J Neurotrauma 2023. [PMID: 36641636 DOI: 10.1089/neu.2023.0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Niklas Marklund
- Department of Clinical Sciences, Lund, Lund University and Skåne University Hospital, Lund, Sweden
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Nordström CH. Letter to the Editor: Rapid Selective Brain Cooling with PolarCap ®-A Commercial Delusion? J Neurotrauma 2023. [PMID: 36448587 DOI: 10.1089/neu.2022.0456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Affiliation(s)
- Carl-Henrik Nordström
- Department of Clinical Sciences, Neurosurgery, Lund University, Lund, Sweden.,Department of Clinical Science, Neurosurgery, University of Southern Denmark, Odense, Denmark
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Baker TS, Zannou AL, Cruz D, Khadka N, Kellner C, Tyc R, Bikson M, Costa A. Development and Clinical Validation of a Finite Element Method Model Mapping Focal Intracranial Cooling. IEEE Trans Neural Syst Rehabil Eng 2022; 30:2168-2174. [PMID: 35316187 PMCID: PMC9533256 DOI: 10.1109/tnsre.2022.3161085] [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] [Indexed: 11/07/2022]
Abstract
Therapeutic hypothermia (TH) is a common and effective technique to reduce inflammation and induce neuroprotection across a variety of diseases. Focal TH of the brain can avoid the side effects of systemic cooling. The degree and extent of focal TH are a function of cooling probe design and local brain thermoregulation processes. To refine focal TH probe design, with application-specific optimization, we develop precise computational models of brain thermodynamics under intense local cooling. Here, we present a novel multiphysics in silico model that can accurately predict brain response to focal cooling. The model was parameterized from previously described values of metabolic activity, thermal conductivity, and temperature-dependent cerebral perfusion. The model was validated experimentally using data from clinical cases where local cooling was induced intracranially and brain temperatures monitored in real-time with MR thermometry. The validated model was then used to identify optimal design probe parameters to maximize volumetric TH, including considering three stratifications of cooling (mild, moderate, and profound) to produce Volume of Tissue Cooled (VOTC) maps. We report cooling radius increases in a nearly linear fashion with probe length and decreasing probe surface temperature.
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Jiang Y, Xie QS, Wu XJ, Shi XL, Huang JX, Wang SH, Zhao YQ, Hu RR, Chen W, Huang CG, Yu MK, Hou LJ. Introduction of a novel, continuous, non-invasive estimation of intracranial pressure and cerebral perfusion pressure based on tympanic membrane temperature. World Neurosurg 2022; 161:e688-e697. [DOI: 10.1016/j.wneu.2022.02.082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 10/19/2022]
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Kublanov VS, Borisov VI, Babich MV. Simulation the distribution of thermodynamic temperatures and microwave radiation of the human head. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 190:105377. [PMID: 32065933 DOI: 10.1016/j.cmpb.2020.105377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/20/2020] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVE The influence of biophysical parameters on the formation of microwave radiation of the human head is poorly studied. Existing approaches to modeling microwave radiation of the human head have limitations associated with simplifying the geometry of human anatomy. The article proposes methodological solutions for numerical modeling of microwave radiation of the brain biological tissues using the geometry obtained from MRI data. METHODS The geometrical characteristics of biological tissues in model are determined using an MRI image of the head. The methodology proposed in the article allows simulation of a human body voxel models performed the Pennes bio-heat transfer equation using the Fenix software package. RESULTS Modeling evaluations have shown that anatomical tissues heterogeneities on the surface of the head form temperature gradient of up to 2.0 K, and changes of the microwave radiation up to 0.3 K. CONCLUSIONS Verification data made by IR thermograph practically coincide with the results of numerical modeling. The fluctuations of the brain microwave radiation are not only the result of thermal processes in its tissues, but are determined by the dynamics of its thermoregulation processes and are an indicator of changes in the physiological processes occurring in it.
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Dugan EA, Bennett C, Tamames I, Dietrich WD, King CS, Prasad A, Rajguru SM. Therapeutic hypothermia reduces cortical inflammation associated with utah array implants. J Neural Eng 2020; 17:026035. [PMID: 32240985 DOI: 10.1088/1741-2552/ab85d2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Neuroprosthetics hold tremendous promise to restore function through brain-computer interfaced devices. However, clinical applications of implantable microelectrodes remain limited given the challenges of maintaining neuronal signals for extended periods of time and with multiple biological mechanisms negatively affecting electrode performance. Acute and chronic inflammation, oxidative stress, and blood brain barrier disruption contribute to inconsistent electrode performance. We hypothesized that therapeutic hypothermia (TH) applied at the microelectrode insertion site will positively modulate both inflammatory and apoptotic pathways, promoting neuroprotection and improved performance in the long-term. APPROACH A custom device and thermoelectric system were designed to deliver controlled TH locally to the cortical implant site at the time of microelectrode array insertion and immediately following surgery. The TH paradigm was derived from in vivo cortical temperature measurements and finite element modeling of temperature distribution profiles in the cortex. Male Sprague-Dawley rats were implanted with non-functional Utah microelectrodes arrays (UMEA) consisting of 4 × 4 grid of 1.5 mm long parylene-coated silicon shanks. In one group, TH was applied to the implant site for two hours following the UMEA implantation, while the other group was implanted under normothermic conditions without treatment. At 48 h, 72 h, 7 d and 14 d post-implantation, mRNA expression levels for genes associated with inflammation and apoptosis were compared between normothermic and hypothermia-treated groups. MAIN RESULTS The custom system delivered controlled TH to the cortical implant site and the numerical models confirmed that the temperature decrease was confined locally. Furthermore, a one-time application of TH post UMEA insertion significantly reduced the acute inflammatory response with a reduction in the expression of inflammatory regulating cytokines and chemokines. SIGNIFICANCE This work provides evidence that acutely applied hypothermia is effective in significantly reducing acute inflammation post intracortical electrode implantation.
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Affiliation(s)
- Elizabeth A Dugan
- Department of Biomedical Engineering, University of Miami, FL, United States of America
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Kuczynski AM, Demchuk AM, Almekhlafi MA. Therapeutic hypothermia: Applications in adults with acute ischemic stroke. Brain Circ 2019; 5:43-54. [PMID: 31334356 PMCID: PMC6611191 DOI: 10.4103/bc.bc_5_19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/05/2019] [Accepted: 04/09/2019] [Indexed: 12/13/2022] Open
Abstract
The advent of mechanical thrombectomy and increasing alteplase use have transformed the care of patients with acute ischemic stroke. Patients with major arterial occlusions with poor outcomes now have a chance of returning to independent living in more than half of the cases. However, many patients with these severe strokes suffer major disability despite these therapies. The search is ongoing for agents that can be combined with thrombectomy to achieve better recovery through halting infarct growth and mitigating injury after ischemic stroke. Several studies in animals and humans have demonstrated that therapeutic hypothermia (TH) offers potential to interrupt the ischemic cascade, reduce infarct volume, and improve functional independence. We performed a literature search to look up recent advances in the use of TH surrounding the science, efficacy, and feasibility of inducing TH in modern stroke treatments. While protocols remain controversial, there is a real opportunity to combine TH with the existing therapies to improve outcome in adults with acute ischemic stroke.
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Affiliation(s)
| | - Andrew M Demchuk
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, AB, Canada
| | - Mohammed A Almekhlafi
- Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Calgary, AB, Canada
- O'Brien Institute for Public Health, Calgary, AB, Canada
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Theoretical Evaluation and Experimental Validation of Localized Therapeutic Hypothermia Application to Preserve Residual Hearing After Cochlear Implantation. Ear Hear 2019; 39:712-719. [PMID: 29240567 DOI: 10.1097/aud.0000000000000529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Cochlear implantation surgery has been shown to result in trauma to inner ear sensory structures, resulting in loss of residual hearing. Localized therapeutic hypothermia has been shown in clinical care to be a neuroprotective intervention. Previously, we have shown in an experimental model that localized hypothermia protects cochlear hair cells and residual hearing function against surgical and cochlear implantation trauma. Using experimental temperature measurements carried out in human cadaver temporal bones and a finite element model of the inner ear, the present study examined the temperature distribution of a custom-designed hypothermia delivery system in the human inner ear organs. DESIGN The efficacy of the hypothermia probe and resulting heat distribution across human cochlea and surrounding tissues were modeled in three-dimensional in COMSOL. The geometry and dimensions of inner ear and temporal bones were derived from computed tomographic and magnetic resonance imaging images. Model predictions were compared with experimental observations from five human temporal bones. RESULTS In both the modeling and experimental studies, the cochlear temperature was lowered by 4 to 6 °C on the round window from a baseline of 37 °C within 16 to 18 minutes. The model simulations showed uniformly distributed cooling across the cochlea. This study provides insight for design, operation, and protocols for efficacious delivery of mild therapeutic hypothermia to the human cochlea that may significantly benefit patients undergoing surgical cochlear implantation by preserving residual hearing. CONCLUSION There was a close correlation between the results of the numerical simulations and experimental observations in this study. Our custom-designed system is capable of effectively providing mild therapeutic hypothermia locally to the human cochlea. When combined with results from in vivo animal experiments, the present study suggests that the application of localized therapeutic hypothermia may hold potential for patients with an aim to preserve residual hearing after cochlear implantation.
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Inducing therapeutic hypothermia via selective brain cooling: a finite element modeling analysis. Med Biol Eng Comput 2019; 57:1313-1322. [PMID: 30756230 DOI: 10.1007/s11517-019-01962-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 02/04/2019] [Indexed: 02/06/2023]
Abstract
Therapeutic hypothermia is a treatment method to reduce brain injuries after stroke, especially for cerebral ischemia. This study investigates in the temperature distribution of the head within selective brain cooling (SBC). Anatomically accurate geometries based on CT images of head and neck regions are used to develop the 3D geometry and physical model for the finite element modeling. Two cooling methods, the direct head surface cooling strategy and the combination cooling strategy of both head and neck, are evaluated to analyze the inducing hypothermia. The results show that for direct head surface cooling, the scalp and skull temperatures decrease significantly as the blood perfusion rate is constrained, but it is hard to affect the brain core temperature. To achieve a lower cerebral temperature, combination cooling strategy of both head and neck is an effective method in improving deep brain cooling. In normal condition, the cerebral temperature is reduced by about 0.12 °C in 60 min of hypothermia, while the temperature drop is approximately 0.98 °C in ischemic condition. Graphical abstract In this study, the 3D geometry of the head and carotid artery model based on the computed tomography (CT) were derived separately and the corresponding investigations were conducted to validate the reliability of the model. Direct head surface cooling strategy and the combination cooling strategy of both the head and neck were numerically researched.
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Baldry M, Timchenko V, Menictas C. Thermal modelling of controlled scalp hypothermia using a thermoelectric cooling cap. J Therm Biol 2018; 76:8-20. [PMID: 30143301 DOI: 10.1016/j.jtherbio.2018.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/20/2018] [Accepted: 06/21/2018] [Indexed: 11/16/2022]
Abstract
This study presents a novel, thermoelectric cryotherapy cap that aims to provide effective and controlled scalp cooling to prevent hair loss for chemotherapy patients. The cap's design consists of multiple thermoelectric coolers (TECs) evenly spaced and bonded to a soft thermal interface material, tightly fitted to a patient's head. A numerical model is developed to assess the performance of alternative cap designs in relation to their ability to achieve hair follicle hypothermia. Under ideal conditions, 26.5 W of heat removal from the scalp is required to achieve the clinically-significant follicle temperature target of 22 °C. Temperature maps of the subcutaneous tissue are generated to visualise the development of hypothermic follicles, and thereby assess the effectiveness of the cap design. Transient studies show that cooling to the therapeutic temperature can be achieved within 40 min. To avoid the possibility of cold-induced tissue damage, individual thermoelectric cooling modules should not be operated at a cooling flux beyond approximately 3175 W/m2. This may be achieved with 38 modules evenly spaced in a checkerboard arrangement, each providing 0.7 W of cooling to the scalp.
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Affiliation(s)
- Mark Baldry
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington 2033, NSW, Australia
| | - Victoria Timchenko
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington 2033, NSW, Australia
| | - Chris Menictas
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington 2033, NSW, Australia.
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Li H, Chen RK, Tang Y, Meurer W, Shih AJ. An experimental study and finite element modeling of head and neck cooling for brain hypothermia. J Therm Biol 2017; 71:99-111. [PMID: 29301706 DOI: 10.1016/j.jtherbio.2017.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/28/2022]
Abstract
Reducing brain temperature by head and neck cooling is likely to be the protective treatment for humans when subjects to sudden cardiac arrest. This study develops the experimental validation model and finite element modeling (FEM) to study the head and neck cooling separately, which can induce therapeutic hypothermia focused on the brain. Anatomically accurate geometries based on CT images of the skull and carotid artery are utilized to find the 3D geometry for FEM to analyze the temperature distributions and 3D-printing to build the physical model for experiment. The results show that FEM predicted and experimentally measured temperatures have good agreement, which can be used to predict the temporal and spatial temperature distributions of the tissue and blood during the head and neck cooling process. Effects of boundary condition, perfusion, blood flow rate, and size of cooling area are studied. For head cooling, the cooling penetration depth is greatly depending on the blood perfusion in the brain. In the normal blood flow condition, the neck internal carotid artery temperature is decreased only by about 0.13°C after 60min of hypothermia. In an ischemic (low blood flow rate) condition, such temperature can be decreased by about 1.0°C. In conclusion, decreasing the blood perfusion and metabolic reduction factor could be more beneficial to cool the core zone. The results also suggest that more SBC researches should be explored, such as the optimization of simulation and experimental models, and to perform the experiment on human subjects.
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Affiliation(s)
- Hui Li
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China; Electronic Paper Display Institute, South China Normal University, Guangzhou 510006, China.
| | - Roland K Chen
- Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA
| | - Yong Tang
- Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
| | - William Meurer
- Department of Emergency Medicine, Department of Neurology, Michigan Center for Integrative Research in Critical Care, University of Michigan Health System, Ann Arbor, MI 48109-5303, USA
| | - Albert J Shih
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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Lillicrap T, Tahtalı M, Neely A, Wang X, Bivard A, Lueck C. A model based on the Pennes bioheat transfer equation is valid in normal brain tissue but not brain tissue suffering focal ischaemia. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:841-850. [PMID: 29098600 DOI: 10.1007/s13246-017-0595-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 10/18/2017] [Indexed: 11/29/2022]
Abstract
Ischaemic stroke is a major public health issue in both developed and developing nations. Hypothermia is believed to be neuroprotective in cerebral ischaemia. Conversely, elevated brain temperature is associated with poor outcome after ischaemic stroke. Mechanisms of heat exchange in normally-perfused brain are relatively well understood, but these mechanisms have not been studied as extensively during focal cerebral ischaemia. A finite element model (FEM) of heat exchange during focal ischaemia in the human brain was developed, based on the Pennes bioheat equation. This model incorporated healthy (normally-perfused) brain tissue, tissue that was mildly hypoperfused but not at risk of cell death (referred to as oligaemia), tissue that was hypoperfused and at risk of death but not dead (referred to as penumbra) and tissue that had died as a result of ischaemia (referred to as infarct core). The results of simulations using this model were found to match previous in-vivo temperature data for normally-perfused brain. However, the results did not match what limited data are available for hypoperfused brain tissue, in particular the penumbra, which is the focus of acute neuroprotective treatments such as hypothermia. These results suggest that the assumptions of the Pennes bioheat equation, while valid in the brain under normal circumstances, are not valid during focal ischaemia. Further investigation into the heat exchange profiles that do occur during focal ischaemia may yield results for clinical trials of therapeutic hypothermia.
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Affiliation(s)
| | - Murat Tahtalı
- School of Engineering and IT, UNSW Canberra, Canberra, Australia
| | - Andrew Neely
- School of Engineering and IT, UNSW Canberra, Canberra, Australia
| | - Xiaofei Wang
- National University of Singapore, Singapore, Singapore
| | - Andrew Bivard
- Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Christian Lueck
- Medical School, Australian National University, Canberra, Australia.,Neurology Department, The Canberra Hospital, Canberra, Australia
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Cattaneo G, Schumacher M, Maurer C, Wolfertz J, Jost T, Büchert M, Keuler A, Boos L, Shah MJ, Foerster K, Niesen WD, Ihorst G, Urbach H, Meckel S. Endovascular Cooling Catheter for Selective Brain Hypothermia: An Animal Feasibility Study of Cooling Performance. AJNR Am J Neuroradiol 2015; 37:885-91. [PMID: 26705319 DOI: 10.3174/ajnr.a4625] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 10/21/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND PURPOSE Therapeutic hypothermia represents a promising neuroprotective treatment in acute ischemic stroke. Selective cerebral hypothermia applied early, prior to and during endovascular mechanical recanalization therapy, may be beneficial in the critical phase of reperfusion. We aimed to assess the feasibility of a new intracarotid cooling catheter in an animal model. MATERIALS AND METHODS Nine adult sheep were included. Temperature probes were introduced into the frontal and temporal brain cortices bilaterally. The cooling catheter system was introduced into a common carotid artery. Selective blood cooling was applied for 180 minutes. Systemic and local brain temperatures were measured during cooling and rewarming. Common carotid artery diameters and flow were measured angiographically and by Doppler sonography. RESULTS The common carotid artery diameter was between 6.7 and 7.3 mm. Common carotid artery blood flow velocities increased moderately during cooling and after catheter removal. Maximum cerebral cooling in the ipsilateral temporal cortex was -4.7°C (95% CI, -5.1 to -4.0°C). Ipsilateral brain temperatures dropped significantly faster and became lower compared with the contralateral cortex with maximum temperature difference of -1.3°C (95% CI, -1.5 to -1.0°C; P < .0001) and compared with systemic temperature (-1.4°C; 95% CI, -1.7 to -1.0°C; P < .0001). CONCLUSIONS Sheep proved a feasible animal model for the intracarotid cooling catheter. Fast induction of selective mild hypothermia was achieved within the cooled cerebral hemisphere, with stable temperature gradients in the contralateral brain and systemic blood. Further studies are required to demonstrate any therapeutic benefit of selective cerebral cooling in a stroke model.
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Affiliation(s)
- G Cattaneo
- From Acandis (G.C., J.W., T.J., M.B.), Pforzheim, Germany
| | - M Schumacher
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
| | - C Maurer
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
| | - J Wolfertz
- From Acandis (G.C., J.W., T.J., M.B.), Pforzheim, Germany
| | - T Jost
- From Acandis (G.C., J.W., T.J., M.B.), Pforzheim, Germany
| | - M Büchert
- From Acandis (G.C., J.W., T.J., M.B.), Pforzheim, Germany
| | - A Keuler
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
| | - L Boos
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
| | | | | | | | - G Ihorst
- University Study Center (G.I.), University Hospital Freiburg, Freiburg, Germany
| | - H Urbach
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
| | - S Meckel
- Departments of Neuroradiology (M.S., C.M., A.K., L.B., H.U., S.M.)
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The effects of physiological thermoregulation on the efficacy of surface cooling for therapeutic hypothermia. Med Biol Eng Comput 2014; 53:205-13. [DOI: 10.1007/s11517-014-1229-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 11/12/2014] [Indexed: 10/24/2022]
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Esposito E, Ebner M, Ziemann U, Poli S. In cold blood: intraarteral cold infusions for selective brain cooling in stroke. J Cereb Blood Flow Metab 2014; 34:743-52. [PMID: 24517972 PMCID: PMC4013766 DOI: 10.1038/jcbfm.2014.29] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/19/2013] [Accepted: 01/19/2014] [Indexed: 12/29/2022]
Abstract
Hypothermia is a promising therapeutic option for stroke patients and an established neuroprotective treatment for global cerebral ischemia after cardiac arrest. While whole body cooling is a feasible approach in intubated and sedated patients, its application in awake stroke patients is limited by severe side effects: Strong shivering rewarms the body and potentially worsens ischemic conditions because of increased O2 consumption. Drugs used for shivering control frequently cause sedation that increases the risk of aspiration and pneumonia. Selective brain cooling by intraarterial cold infusions (IACIs) has been proposed as an alternative strategy for patients suffering from acute ischemic stroke. Preclinical studies and early clinical experience indicate that IACI induce a highly selective brain temperature decrease within minutes and reach targeted hypothermia 10 to 30 times faster than conventional cooling methods. At the same time, body core temperature remains largely unaffected, thus systemic side effects are potentially diminished. This review critically discusses the limitations and side effects of current cooling techniques for neuroprotection from ischemic brain damage and summarizes the available evidence regarding advantages and potential risks of IACI.
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Affiliation(s)
- Elga Esposito
- Department Neurology & Stroke, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Matthias Ebner
- Department Neurology & Stroke, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ulf Ziemann
- Department Neurology & Stroke, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Sven Poli
- Department Neurology & Stroke, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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Poli S, Purrucker J, Priglinger M, Diedler J, Sykora M, Popp E, Steiner T, Veltkamp R, Bösel J, Rupp A, Hacke W, Hametner C. Induction of cooling with a passive head and neck cooling device: effects on brain temperature after stroke. Stroke 2013; 44:708-13. [PMID: 23339959 DOI: 10.1161/strokeaha.112.672923] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Therapeutic hypothermia improves clinical outcome after cardiac arrest and appears beneficial in other cerebrovascular diseases. We conducted this study to investigate the relationship between surface head/neck cooling and brain temperature. METHODS Prospective observational study enrolling consecutive patients with severe ischemic or hemorrhagic stroke undergoing intracranial pressure (ICP) and brain temperature monitoring. Arterial pressure, ICP, cerebral perfusion pressure, heart rate, brain, tympanic, and bladder temperature were continuously registered. Fifty-one applications of the Sovika cooling device were analyzed in 11 individual patients. RESULTS Sovika application led to a significant decrease of brain temperature compared with baseline with a maximum of -0.36°C (SD, 0.22) after 49 minutes (SD, 17). During cooling, dynamics of brain temperature differed significantly from bladder (-0.25°C [SD, 0.15] after 48 minutes [SD, 19]) and tympanic temperature (-1.79°C [SD, 1.19] after 37 minutes [SD, 16]). Treatment led to an increase in systolic arterial pressure by >20 mm Hg in 14 applications (n=7 patients) resulting in severe hypertension (>180 mm Hg) in 4 applications (n=3). ICP increased by >10 mm Hg in 7 applications (n=3), led to ICP crisis >20 mm Hg in 6 applications (n=3), and a drop of cerebral perfusion pressure <50 mm Hg in 1 application. CONCLUSIONS Although the decrease of brain temperature after Sovika cooling device application was statistically significant, we doubt clinical relevance of this rather limited effect (-0.36°C). Moreover, the transient increases of blood pressure and ICP warrant caution.
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Affiliation(s)
- Sven Poli
- Department of Neurology, University of Heidelberg, Heidelberg, Germany
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Abstract
OPINION STATEMENT Therapeutic hypothermia has proven neuroprotective effects in global cerebral ischemia. Indications for hypothermia induction include cardiac arrest and neonatal asphyxia. The two general methods of induced hypothermia are either surface cooling or endovascular cooling. Hypothermia should be induced as early as possible to achieve maximum neuroprotection and edema blocking effect. Endovascular cooling has the benefit of shorter time to reach target temperature but catheter insertion requires expertise and training, which may be a barrier to widespread availability. The optimum method of cooling is yet to be determined but a multimodal approach is necessary to address three phases of cooling: induction, maintentance, and rewarm. Specifying core practitioners who are well-versed in established guidelines can help integrate the multidisciplinary team that is needed to successfully implement cooling protocols. Reducing shivering to make heat exchange more efficient with tighter temperature control enables quicker time to target temperature and avoids rewarming which can lead to inadvertent increase in intracranial pressure and cerebral edema. Promising applications but yet to be determined is whether hypothermia treatment can improve outcomes in acute ischemic stroke or traumatic brain injury.
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Affiliation(s)
- Shlee S Song
- Department of Neurology, Cedars-Sinai Medical Center, 8730 Alden Drive, Suite E-240, Los Angeles, CA, 90048, USA
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Campos F, Blanco M, Barral D, Agulla J, Ramos-Cabrer P, Castillo J. Influence of temperature on ischemic brain: Basic and clinical principles. Neurochem Int 2012; 60:495-505. [DOI: 10.1016/j.neuint.2012.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Revised: 01/31/2012] [Accepted: 02/04/2012] [Indexed: 12/24/2022]
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Mink S, Schwarz U, Mudra R, Gugl C, Fröhlich J, Keller E. Treatment of resistant fever: new method of local cerebral cooling. Neurocrit Care 2012; 15:107-12. [PMID: 20886310 DOI: 10.1007/s12028-010-9451-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Fever in neurocritical care patients is common and has a negative impact on neurological outcome. The purpose of this prospective observational study was (1) to evaluate the practicability of cooling with newly developed neck pads in the daily setting of neurointensive care unit (NICU) patients and (2) to evaluate its effectiveness as a surrogate endpoint to indicate the feasibility of neck cooling as a new method for intractable fever. METHODS Nine patients with ten episodes of intractable fever and aneurysmal subarachnoid hemorrhage were treated with one of two different shapes of specifically adapted cooling neck pads. Temperature values of the brain, blood, and urinary bladder were taken close meshed after application of the cooling neck pads up to hour 8. RESULTS The brain, blood, and urinary bladder temperatures decreased significantly from hour 0 to a minimum in hour 5 (P < 0.01). After hour 5, instead of continuous cooling in all the patients, the temperature of all the three sites remounted. CONCLUSION This study showed the practicability of local cooling for intractable fever using the newly developed neck pads in the daily setting of NICU patients.
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Affiliation(s)
- Susanne Mink
- Department of Neurosurgery, Neuroscience Intensive Care Unit, University Hospital of Zurich, Zurich, Switzerland.
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Faridar A, Bershad EM, Emiru T, Iaizzo PA, Suarez JI, Divani AA. Therapeutic hypothermia in stroke and traumatic brain injury. Front Neurol 2011; 2:80. [PMID: 22207862 PMCID: PMC3246360 DOI: 10.3389/fneur.2011.00080] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 11/22/2011] [Indexed: 11/30/2022] Open
Abstract
Therapeutic hypothermia (TH) is considered to improve survival with favorable neurological outcome in the case of global cerebral ischemia after cardiac arrest and perinatal asphyxia. The efficacy of hypothermia in acute ischemic stroke (AIS) and traumatic brain injury (TBI), however, is not well studied. Induction of TH typically requires a multimodal approach, including the use of both pharmacological agents and physical techniques. To date, clinical outcomes for patients with either AIS or TBI who received TH have yielded conflicting results; thus, no adequate therapeutic consensus has been reached. Nevertheless, it seems that by determining optimal TH parameters and also appropriate applications, cooling therapy still has the potential to become a valuable neuroprotective intervention. Among the various methods for hypothermia induction, intravascular cooling (IVC) may have the most promise in the awake patient in terms of clinical outcomes. Currently, the IVC method has the capability of more rapid target temperature attainment and more precise control of temperature. However, this technique requires expertise in endovascular surgery that can preclude its application in the field and/or in most emergency settings. It is very likely that combining neuroprotective strategies will yield better outcomes than utilizing a single approach.
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Affiliation(s)
- Alireza Faridar
- Department of Neurology, University of Minnesota Minneapolis, MN, USA
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Kallmünzer B, Beck A, Schwab S, Kollmar R. Local head and neck cooling leads to hypothermia in healthy volunteers. Cerebrovasc Dis 2011; 32:207-10. [PMID: 21822012 DOI: 10.1159/000329376] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 05/03/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Prehospital cooling of acute stroke patients would be ideal when associated with minor or no side effects. Therefore, we evaluated a cooling cap for the surface of head and cervical regions in awake volunteers. METHODS 10 healthy volunteers were treated by external cooling for 190 min using a gel-based cooling device. Vital signs, rectal temperature, tympanic temperature, the extent of shivering and individual perception of frostiness and discomfort were measured. RESULTS All participants (median age 35 years) successfully completed the treatment and experienced only mild to moderate discomfort. No serious adverse events and no shivering were noticed. There was a significant drop in the tympanic temperature to 34.68°C (difference from baseline: 1.7°C, 95% CI: 0.61-2.7°C, p = 0.001), in the rectal temperature to 36.65°C (difference from baseline: 0.65°C, 95% CI: 0.06-1.2°C, p = 0.019) and in the heart rate (difference from baseline: 15 beats/min, 95% CI: 0.63-30 beats/min, p = 0.035). CONCLUSION Treatment with the cooling device was well tolerated by all participants. The technique had measurable effects on core body temperature (rectal) and tympanic temperature (may reflect temperature at the external ear and skin rather than intracranial). It can be considered as a simple therapeutic approach to patients with suspected stroke in the prehospital setting.
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Affiliation(s)
- Bernd Kallmünzer
- Department of Neurology, University Hospital Erlangen, Friedrich Alexander University Erlangen-Nürnberg, Erlangen, Germany.
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Weihs W, Schratter A, Sterz F, Janata A, Högler S, Holzer M, Losert UM, Herkner H, Behringer W. The importance of surface area for the cooling efficacy of mild therapeutic hypothermia. Resuscitation 2011; 82:74-8. [PMID: 21036458 DOI: 10.1016/j.resuscitation.2010.09.472] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 08/31/2010] [Accepted: 09/25/2010] [Indexed: 11/19/2022]
Affiliation(s)
- Wolfgang Weihs
- Department of Emergency Medicine, Medical University of Vienna, Austria
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Current world literature. Curr Opin Anaesthesiol 2010; 23:283-93. [PMID: 20404787 DOI: 10.1097/aco.0b013e328337578e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Therapeutic hypothermia is a means of neuroprotection well established in the management of acute ischemic brain injuries such as anoxic encephalopathy after cardiac arrest and perinatal asphyxia. As such, it is the only neuroprotective strategy for which there is robust evidence for efficacy. Although there is overwhelming evidence from animal studies that cooling also improves outcome after focal cerebral ischemia, this has not been adequately tested in patients with acute ischemic stroke. There are still some uncertainties about crucial factors relating to the delivery of hypothermia, and the resolution of these would allow improvements in the design of phase III studies in these patients and improvements in the prospects for successful translation. In this study, we discuss critical issues relating first to the targets for therapy including the optimal depth and duration of cooling, second to practical issues including the methods of cooling and the management of shivering, and finally, of factors relating to the design of clinical trials. Consideration of these factors should inform the development of strategies to establish beyond doubt the place of hypothermia in the management of acute ischemic stroke.
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