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Cui HC, Chang ZQ, Zhao SK. Atypical cervical spondylotic radiculopathy resulting in a hypertensive emergency during cervical extension: A case report and review of literature. World J Orthop 2024; 15:981-990. [DOI: 10.5312/wjo.v15.i10.981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 09/06/2024] [Accepted: 09/14/2024] [Indexed: 10/11/2024] Open
Abstract
BACKGROUND Extensive research revealed the absence of reports documenting hypertensive emergencies precipitated by changes in the cervical spine posture.
CASE SUMMARY We here present a 57-year-old woman diagnosed as having cervical spondylotic radiculopathy (CSR) who was scheduled for anterior cervical decompression and fusion. During post-anesthetic positioning, a sudden hypertensive surge was observed when the patient was in a supine position with the neck being slightly extended. This surge was promptly reversed through cervical flexion and head elevation. This event however required an alternate surgical approach for recovery—posterior laminoplasty and endoscopy-assisted nucleus pulposus removal. Following the 6-month outpatient follow-up period, cervical flexion and extension activities substantially improved in the patient without any episodes of increase in acute blood pressure.
CONCLUSION Maintaining a safe hypotensive posture and performing rapid, thorough decompression surgery may serve as effective interventions for patients presenting symptoms similar to those of CSR accompanied by hypertensive emergencies (HE). This would mitigate the underlying causes of these HEs.
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Affiliation(s)
- Hao-Cheng Cui
- Department of Orthopedic Surgery, 960th Hospital of PLA, Jinan 250031, Shandong Province, China
| | - Zheng-Qi Chang
- Department of Orthopedic Surgery, 960th Hospital of PLA, Jinan 250031, Shandong Province, China
| | - Shao-Ke Zhao
- Department of Orthopedic Surgery, 960th Hospital of PLA, Jinan 250031, Shandong Province, China
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2
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Trimmel NE, Podgoršak A, Oertel MF, Jucker S, Arras M, Schmid Daners M, Weisskopf M. The Sheep as a Comprehensive Animal Model to Investigate Interdependent Physiological Pressure Propagation and Multiparameter Influence on Cerebrospinal Fluid Dynamics. Front Neurosci 2022; 16:868567. [PMID: 35431780 PMCID: PMC9008349 DOI: 10.3389/fnins.2022.868567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/09/2022] [Indexed: 11/18/2022] Open
Abstract
The present study aims to develop a suitable animal model for evaluating the physiological interactions between cerebrospinal fluid (CSF) dynamics, hemodynamics, and abdominal compartment pressures. We seek to contribute to the enhanced recognition of the pathophysiology of CSF-dependent neurological disorders like hydrocephalus and the improvement of available treatment options. To date, no comprehensive animal model of CSF dynamics exists, and establishing an accurate model will advance our understanding of complex CSF physiology. Persisting knowledge gaps surrounding the communication and pressure propagation between the cerebrospinal space and adjacent anatomical compartments exacerbate the development of novel therapies for neurological diseases. Hence, the need for further investigation of the interactions of vascular, craniospinal, and abdominal pressures remains beyond dispute. Moreover, the results of this animal study support the optimization of in vitro test benches for medical device development, e.g., ventriculoperitoneal shunts. Six female white alpine sheep were surgically equipped with pressure sensors to investigate the physiological values of intracranial, intrathecal, arterial, central venous, jugular venous, vesical pressure, and four differently located abdominal pressures. These values were measured simultaneously during the acute animal trial with sheep under general anesthesia. Both carotid and femoral arterial blood pressure indicate a reliable and comparable representation of the systematic blood pressure. However, the jugular venous pressure and the central venous pressure in sheep in dorsal recumbency do not correlate well under general anesthesia. Furthermore, there is a trend for possible comparability of lateral intraventricular and lumbar intrathecal pressure. Nevertheless, animal body position during measurements must be considered since different body constitutions can alter the horizontal line between the cerebral ventricles and the lumbar subarachnoid space. While intra-abdominal pressure measurement in the four different abdominal quadrants yielded greater inter-individual variability, intra-vesical pressure measurements in our setting delivered comparable values for all sheep. We established a novel and comprehensive ovine animal model to investigate interdependent physiologic pressure propagation and multiparameter influences on CSF dynamics. The results of this study will contribute to further in vitro bench testing, the derivation of novel quantitative models, and the development of a pathologic ovine hydrocephalus model.
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Affiliation(s)
- Nina Eva Trimmel
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Anthony Podgoršak
- Department of Mechanical and Process Engineering, ETH Zürich, Zurich, Switzerland
| | - Markus Florian Oertel
- Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Simone Jucker
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Margarete Arras
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Miriam Weisskopf
- Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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3
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Janes F, Lorenzut S, Bevilacqua F, de Biase S, Zilli M, Gigli GL, Valente M. Cerebrovascular Risk in Restless Legs Syndrome: Intima-Media Thickness and Cerebral Vasomotor Reactivity: A Case-Control Study. Nat Sci Sleep 2021; 13:967-975. [PMID: 34234599 PMCID: PMC8254097 DOI: 10.2147/nss.s302749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/22/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Although some studies have suggested an association between cardiovascular disease and restless legs syndrome (RLS), the mechanisms underlying this relationship remain unclear. The intima-media thickness (IMT) and vasomotor reactivity are two simple, non-invasive tools to investigate preclinical atherosclerosis and microangiopathy, respectively. The aims of this study were to evaluate carotid IMT and to explore vasomotor reactivity in idiopathic RLS (iRLS) patients. PATIENTS AND METHODS We enrolled 44 iRLS after exclusion of patients with secondary causes of RLS, history of vascular events, known uncontrolled vascular risk factors and other neurological disorders. Forty-four age and sex matched controls were therefore recruited. No significant differences in demographic data and vascular risk factors were found between the two groups. Carotid IMT was measured with a high-resolution B-mode ultrasound on the far-wall of common carotid artery, 10 mm and 30 mm to the carotid bulb. Vasomotor reactivity to hypo- and hypercapnia was assessed, by right middle cerebral artery transcranial Doppler, accordingly to the changes in peak systolic velocity, peak diastolic velocity and mean blood flow velocity. RESULTS Mean IMT was significantly increased in patients with iRLS when measured immediately proximally to carotid bifurcation (0.73; sd=0.17), versus controls (0.65; sd=0.13); p=0.035. Patients showed higher cerebrovascular flow velocities (CBFVs) compared to controls. After multivariate analysis, age, hypertension and iRLS proved to be independent IMT predictors. CONCLUSION Increased IMT and higher CBFVs in iRLS support the association of iRLS with vascular damage, possibly through enhanced atherogenesis and sympathetic hyperactivity. However, to clarify a causal relationship, further longitudinal assessment of these parameters is needed, trying to control all their physiological modifying factors.
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Affiliation(s)
- Francesco Janes
- Department of Neuroscience, S. Maria della Misericordia University Hospital, Udine, Italy
| | - Simone Lorenzut
- Department of Neuroscience, S. Maria della Misericordia University Hospital, Udine, Italy
| | | | | | - Michela Zilli
- Department of 'Area MEdica', University of Udine, Udine, Italy
| | - Gian Luigi Gigli
- Department of Neuroscience, S. Maria della Misericordia University Hospital, Udine, Italy.,Department of 'Area MEdica', University of Udine, Udine, Italy
| | - Mariarosaria Valente
- Department of Neuroscience, S. Maria della Misericordia University Hospital, Udine, Italy.,Department of 'Area MEdica', University of Udine, Udine, Italy
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Zavhorodnia VA, Androshchuk OI, Kharchenko TH, Kudii LI, Kovalenko SO. Haemodynamic effects of hyperventilation on healthy men with different levels of autonomic tone. REGULATORY MECHANISMS IN BIOSYSTEMS 2020. [DOI: 10.15421/022002] [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] Open
Abstract
The topicality of the research is stipulated by insufficient study of the correlation between the functional state of the cardiorespiratory system and autonomic tone. The goal of the research was to analyze the changes of central haemodynamics with 10-minute regulated breathing at the rate of 30 cycles per minute and within 40 minutes of recovery after the test in healthy young men with different levels of autonomic tone. Records of the chest rheoplethysmogram were recorded on a rheograph KhAI-medica standard (KhAI-medica, Kharkiv, Ukraine), a capnogram - in a lateral flow on a infrared capnograph (Datex, Finland), and the duration of R-R intervals was determined by a Polar WIND Link in the program of Polar Protrainer 5.0 (Polar Electro OY, Finland). Systolic and diastolic blood pressure were measured by Korotkov’s auscultatory method by mercury tonometer (Riester, Germany). The indicator of the normalized power of the spectrum in the range of 0.15–0.40 Hz was evaluated by 5-minute records; three groups of persons were distinguished according to its distribution at rest by the method of signal deviation, namely, sympathicotonic, normotonic and parasympathicotonic. The initial level of autonomic tone was found to impact the dynamics of СО2 level in alveolar air during hyperventilation and during recovery thereafter. Thus, PetCО2 was higher (41.3 mm Hg) in parasympathicotonic than in sympathicotonic (39.3 mm Hg) and normotonic (39.5 mm Hg) persons. During the test, R-R interval duration decreased being more expressed in normotonic persons. At the same time, the heart index was found to increase in three groups, and general peripheral resistance – to decrease mostly in normo- and parasympathicotonic persons. In addition, the reliable increase of stroke index and heart index was found in these groups. In the recovery period after hyperventilation, the decrease of tension index and ejection speed was found in normo- and, particularly, parasympathicotonic compared with sympathicotonic men and the increase of tension phase and ejection phase duration.
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Zheng S, Muheremu A, Sun Y, Tian W, Wu CA. Preoperative imaging differences of patients with cervical spondylosis with cervical vertigo indicate the prognosis after cervical total disc replacement. J Int Med Res 2019; 48:300060519877033. [PMID: 31640443 PMCID: PMC7607185 DOI: 10.1177/0300060519877033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To evaluate the relationship between the preoperative imaging differences and prognosis in patients with cervical spondylosis with cervical vertigo who underwent total disc replacement (TDR). METHODS This was a retrospective study of patients with cervical spondylosis with cervical vertigo treated with single-segment TDR. The severity of pre- and postoperative cervical vertigo was evaluated separately. Paired samples t-tests were used to compare the severity of the symptoms before and after surgery. Characteristics of plain films, computed tomography myelography and magnetic resonance imaging were compared between patients with different outcomes by analysis of variance and Fisher's exact tests. RESULTS The severity of cervical vertigo was significantly different after single-segment TDR. Three groups with different treatment outcomes were not significantly different with regard to gender, age, type of the cervical spondylosis, follow-up time, segment of surgery, cervical curve, range of motion, T2WI high signal in the spinal cord, and location of compression. The type of compression was significantly different between the three groups. CONCLUSIONS Cervical vertigo was improved in patients with cervical spondylosis through the TDR procedure. Those in whom a herniated disc was the main source of compression may have a better prognosis following TDR.
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Affiliation(s)
- Shan Zheng
- Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing, China
| | | | - Yuqing Sun
- Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing, China
| | - Wei Tian
- Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing, China
| | - Cheng-Ai Wu
- Department of Molecular Orthopaedics, Beijing Institute of Traumatology and Orthopaedics, Beijing, China
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Bojić T. Editorial: Neurocardiovascular Diseases: New Aspects of the Old Issues. Front Neurosci 2019; 12:1032. [PMID: 30686991 PMCID: PMC6336917 DOI: 10.3389/fnins.2018.01032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 12/20/2018] [Indexed: 11/24/2022] Open
Affiliation(s)
- Tijana Bojić
- Laboratory of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences Vinča, University of Belgrade, Belgrade, Serbia
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7
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Prone sleeping position in infancy: Implications for cardiovascular and cerebrovascular function. Sleep Med Rev 2018; 39:174-186. [DOI: 10.1016/j.smrv.2017.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/30/2017] [Accepted: 10/09/2017] [Indexed: 01/14/2023]
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Associated with Ischemic Stroke Risk Reduction after Endoscopic Thoracic Sympathectomy for Palmar Sweating. J Stroke Cerebrovasc Dis 2018; 27:2235-2242. [PMID: 29784606 DOI: 10.1016/j.jstrokecerebrovasdis.2018.04.007] [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: 01/25/2018] [Revised: 03/18/2018] [Accepted: 04/07/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Endoscopic thoracic sympathectomy (ETS) was performed to cure palmar hyperhidrosis (PH). After ETS, blood pressure decreased, and cerebral flow velocity increased within 1 month. However, no studies distinguish between subsequent ischemic and hemorrhagic stroke following ETS for PH. The association between stroke type and PH after ETS must be evaluated. METHODS We surveyed newly diagnosed patients with PH using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic code 780.8 from the Taiwan Longitudinal National Health Insurance Database. We matched patients with PH who underwent ETS (procedure code 05.29) and without surgery in the database between 2000 and 2010. We defined events as ischemic stroke (ICD-9-CM codes from 433 to 437) or hemorrhagic stroke (ICD-9-CM codes from 430 to 432). Patients were followed up until the first event or December 31, 2010. Risk factors for ischemic stroke and hemorrhagic stroke were analyzed using multivariable Cox proportional hazard regression. RESULTS The incidence of ischemic stroke was significantly lower in patients who underwent ETS (.22%) than in patients without surgery (.65%). The patients with PH who received ETS exhibited a reduced risk of ischemic stroke (adjusted hazard ratio [HR] .3; 95% confidence interval [CI] .12-.77). ETS treatment was not associated with a reduction in hemorrhagic stroke (adjusted HR .81; 95% CI .22-3; P = .755). CONCLUSIONS ETS in patients with PH was associated with reduced subsequent ischemic stroke risk. This additional ischemic stroke preventive effect should encourage health-care supporters to perform ETS in patients with severe PH.
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Kalicka R, Mazur K, Wolf J, Frydrychowski AF, Narkiewicz K, Winklewski PJ. Modelling of subarachnoid space width changes in apnoea resulting as a function of blood flow parameters. Microvasc Res 2017; 113:16-21. [DOI: 10.1016/j.mvr.2017.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 03/14/2017] [Accepted: 03/19/2017] [Indexed: 11/30/2022]
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Yang T, Sun Y, Lu Z, Leak RK, Zhang F. The impact of cerebrovascular aging on vascular cognitive impairment and dementia. Ageing Res Rev 2017; 34:15-29. [PMID: 27693240 DOI: 10.1016/j.arr.2016.09.007] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/09/2016] [Accepted: 09/26/2016] [Indexed: 02/07/2023]
Abstract
As human life expectancy rises, the aged population will increase. Aging is accompanied by changes in tissue structure, often resulting in functional decline. For example, aging within blood vessels contributes to a decrease in blood flow to important organs, potentially leading to organ atrophy and loss of function. In the central nervous system, cerebral vascular aging can lead to loss of the integrity of the blood-brain barrier, eventually resulting in cognitive and sensorimotor decline. One of the major of types of cognitive dysfunction due to chronic cerebral hypoperfusion is vascular cognitive impairment and dementia (VCID). In spite of recent progress in clinical and experimental VCID research, our understanding of vascular contributions to the pathogenesis of VCID is still very limited. In this review, we summarize recent findings on VCID, with a focus on vascular age-related pathologies and their contribution to the development of this condition.
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Affiliation(s)
- Tuo Yang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yang Sun
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhengyu Lu
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese, Shanghai 200437, China
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, USA
| | - Feng Zhang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Key Lab of Cerebral Microcirculation in Universities of Shandong, Taishan Medical University, Taian, Shandong, 271000, China.
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Bain AR, Nybo L, Ainslie PN. Cerebral Vascular Control and Metabolism in Heat Stress. Compr Physiol 2016; 5:1345-80. [PMID: 26140721 DOI: 10.1002/cphy.c140066] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review provides an in-depth update on the impact of heat stress on cerebrovascular functioning. The regulation of cerebral temperature, blood flow, and metabolism are discussed. We further provide an overview of vascular permeability, the neurocognitive changes, and the key clinical implications and pathologies known to confound cerebral functioning during hyperthermia. A reduction in cerebral blood flow (CBF), derived primarily from a respiratory-induced alkalosis, underscores the cerebrovascular changes to hyperthermia. Arterial pressures may also become compromised because of reduced peripheral resistance secondary to skin vasodilatation. Therefore, when hyperthermia is combined with conditions that increase cardiovascular strain, for example, orthostasis or dehydration, the inability to preserve cerebral perfusion pressure further reduces CBF. A reduced cerebral perfusion pressure is in turn the primary mechanism for impaired tolerance to orthostatic challenges. Any reduction in CBF attenuates the brain's convective heat loss, while the hyperthermic-induced increase in metabolic rate increases the cerebral heat gain. This paradoxical uncoupling of CBF to metabolism increases brain temperature, and potentiates a condition whereby cerebral oxygenation may be compromised. With levels of experimentally viable passive hyperthermia (up to 39.5-40.0 °C core temperature), the associated reduction in CBF (∼ 30%) and increase in cerebral metabolic demand (∼ 10%) is likely compensated by increases in cerebral oxygen extraction. However, severe increases in whole-body and brain temperature may increase blood-brain barrier permeability, potentially leading to cerebral vasogenic edema. The cerebrovascular challenges associated with hyperthermia are of paramount importance for populations with compromised thermoregulatory control--for example, spinal cord injury, elderly, and those with preexisting cardiovascular diseases.
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Affiliation(s)
- Anthony R Bain
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Philip N Ainslie
- Centre for Heart Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, Canada
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Ogoh S, Hirasawa A, Sugawara J, Nakahara H, Ueda S, Shoemaker JK, Miyamoto T. The effect of an acute increase in central blood volume on the response of cerebral blood flow to acute hypotension. J Appl Physiol (1985) 2015; 119:527-33. [DOI: 10.1152/japplphysiol.00277.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/07/2015] [Indexed: 11/22/2022] Open
Abstract
The purpose of the present study was to examine whether the response of cerebral blood flow to an acute change in perfusion pressure is modified by an acute increase in central blood volume. Nine young, healthy subjects voluntarily participated in this study. To measure dynamic cerebral autoregulation during normocapnic and hypercapnic (5%) conditions, the change in middle cerebral artery mean blood flow velocity was analyzed during acute hypotension caused by two methods: 1) thigh-cuff occlusion release (without change in central blood volume); and 2) during the recovery phase immediately following release of lower body negative pressure (LBNP; −50 mmHg) that initiated an acute increase in central blood volume. In the thigh-cuff occlusion release protocol, as expected, hypercapnia decreased the rate of regulation, as an index of dynamic cerebral autoregulation (0.236 ± 0.018 and 0.167 ± 0.025 s−1, P = 0.024). Compared with the cuff-occlusion release, the acute increase in central blood volume (relative to the LBNP condition) with LBNP release attenuated dynamic cerebral autoregulation ( P = 0.009). Therefore, the hypercapnia-induced attenuation of dynamic cerebral autoregulation was not observed in the LBNP release protocol ( P = 0.574). These findings suggest that an acute change in systemic blood distribution modifies dynamic cerebral autoregulation during acute hypotension.
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Affiliation(s)
| | | | - Jun Sugawara
- National Institute of Advanced Industrial Science and Technology, Ibaraki Japan
| | | | - Shinya Ueda
- Morinomiya University of Medical Sciences, Osaka, Japan; and
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Winklewski PJ, Barak O, Madden D, Gruszecka A, Gruszecki M, Guminski W, Kot J, Frydrychowski AF, Drvis I, Dujic Z. Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers. PLoS One 2015; 10:e0135429. [PMID: 26285143 PMCID: PMC4540420 DOI: 10.1371/journal.pone.0135429] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 07/21/2015] [Indexed: 11/30/2022] Open
Abstract
Purpose The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). Methods The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Results Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Conclusions Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.
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Affiliation(s)
- Pawel J. Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland
- * E-mail:
| | - Otto Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Dennis Madden
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Agnieszka Gruszecka
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Marcin Gruszecki
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Guminski
- Department of Computer Communications, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | | | - Ivan Drvis
- University of Zagreb School of Kinesiology, Zagreb, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
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Winklewski PJ, Tkachenko Y, Mazur K, Kot J, Gruszecki M, Guminski W, Czuszynski K, Wtorek J, Frydrychowski AF. Sympathetic Activation Does Not Affect the Cardiac and Respiratory Contribution to the Relationship between Blood Pressure and Pial Artery Pulsation Oscillations in Healthy Subjects. PLoS One 2015; 10:e0135751. [PMID: 26284650 PMCID: PMC4540578 DOI: 10.1371/journal.pone.0135751] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/25/2015] [Indexed: 12/12/2022] Open
Abstract
Introduction Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects. Methods The pial artery and subarachnoid width response to handgrip (HGT) and cold test (CT) were studied in 20 healthy subjects. The cc-TQ and sas-TQ were measured using NIR-T/BSS; cerebral blood flow velocity (CBFV) was measured using Doppler ultrasound of the left internal carotid artery; heart rate (HR) and beat-to-beat mean BP were recorded using a continuous finger-pulse photoplethysmography; respiratory rate (RR), minute ventilation (MV), end-tidal CO2 (EtCO2) and end-tidal O2 (EtO2) were measured using a metabolic and spirometry module of the medical monitoring system. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. Results HGT evoked an increase in BP (+15.9%; P<0.001), HR (14.7; P<0.001), SaO2 (+0.5; P<0.001) EtO2 (+2.1; P<0.05) RR (+9.2%; P = 0.05) and MV (+15.5%; P<0.001), while sas-TQ was diminished (-8.12%; P<0.001), and a clear trend toward cc-TQ decline was observed (-11.0%; NS). CBFV (+2.9%; NS) and EtCO2 (-0.7; NS) did not change during HGT. CT evoked an increase in BP (+7.4%; P<0.001), sas-TQ (+3.5%; P<0.05) and SaO2(+0.3%; P<0.05). HR (+2.3%; NS), CBFV (+2.0%; NS), EtO2 (-0.7%; NS) and EtCO2 (+0.9%; NS) remained unchanged. A trend toward decreased cc-TQ was observed (-5.1%; NS). The sas-TQ response was biphasic with elevation during the first 40 seconds (+8.8% vs. baseline; P<0.001) and subsequent decline (+4.1% vs. baseline; P<0.05). No change with respect to wavelet coherence and wavelet phase coherence was found between the BP and cc-TQ oscillations. Conclusions Short sympathetic activation does not affect the cardiac and respiratory contribution to the relationship between BP—cc-TQ oscillations. HGT and CT display divergent effects on the width of the subarachnoid space, an indirect marker of changes in intracranial pressure.
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Affiliation(s)
- Pawel J. Winklewski
- Institute of Human Physiology, Medical University of Gdansk, Gdansk, Poland
- * E-mail:
| | - Yurii Tkachenko
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | - Kamila Mazur
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jacek Kot
- National Centre for Hyperbaric Medicine, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Gdynia, Poland
| | - Marcin Gruszecki
- Department of Radiology Informatics and Statistics, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Guminski
- Department of Computer Communications, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Krzysztof Czuszynski
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
| | - Jerzy Wtorek
- Department of Biomedical Engineering, Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, Gdansk, Poland
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Abstract
Cerebral autoregulation describes a mechanism that maintains cerebral blood flow stable despite fluctuating perfusion pressure. Multiple nonperfusion pressure processes also regulate cerebral perfusion. These mechanisms are integrated. The effect of the interplay between carbon dioxide and perfusion pressure on cerebral circulation has not been specifically reviewed. On the basis of the published data and speculation on the aspects that are without supportive data, the authors offer a conceptualization delineating the regulation of cerebral autoregulation by carbon dioxide. The authors conclude that hypercapnia causes the plateau to progressively ascend, a rightward shift of the lower limit, and a leftward shift of the upper limit. Conversely, hypocapnia results in the plateau shifting to lower cerebral blood flows, unremarkable change of the lower limit, and unclear change of the upper limit. It is emphasized that a sound understanding of both the limitations and the dynamic and integrated nature of cerebral autoregulation fosters a safer clinical practice.
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Abstract
Cervical spondylosis and hypertension are all common diseases, but the relationship between them has never been studied. Patients with cervical spondylosis are often accompanied with vertigo. Anterior cervical discectomy and fusion is an effective method of treatment for cervical spondylosis with cervical vertigo that is unresponsive to conservative therapy. We report 2 patients of cervical spondylosis with concomitant cervical vertigo and hypertension who were treated successfully with anterior cervical discectomy and fusion. Stimulation of sympathetic nerve fibers in pathologically degenerative disc could produce sympathetic excitation, and induce a sympathetic reflex to cause cervical vertigo and hypertension. In addition, chronic neck pain could contribute to hypertension development through sympathetic arousal and failure of normal homeostatic pain regulatory mechanisms. Cervical spondylosis may be one of the causes of secondary hypertension. Early treatment for resolution of symptoms of cervical spondylosis may have a beneficial impact on cardiovascular disease risk in patients with cervical spondylosis.
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Affiliation(s)
- Baogan Peng
- From the Department of Spinal Surgery, General Hospital of Armed Police Force, Beijing, China
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17
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Regulation of brain blood flow and oxygen delivery in elite breath-hold divers. J Cereb Blood Flow Metab 2015; 35:66-73. [PMID: 25370857 PMCID: PMC4294396 DOI: 10.1038/jcbfm.2014.170] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 01/07/2023]
Abstract
The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.
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18
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Static autoregulation in humans: a review and reanalysis. Med Eng Phys 2014; 36:1487-95. [DOI: 10.1016/j.medengphy.2014.08.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 06/07/2014] [Accepted: 08/03/2014] [Indexed: 01/12/2023]
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Brew N, Walker D, Wong FY. Cerebral vascular regulation and brain injury in preterm infants. Am J Physiol Regul Integr Comp Physiol 2014; 306:R773-86. [PMID: 24647591 DOI: 10.1152/ajpregu.00487.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebrovascular lesions, mainly germinal matrix hemorrhage and ischemic injury to the periventricular white matter, are major causes of adverse neurodevelopmental outcome in preterm infants. Cerebrovascular lesions and neuromorbidity increase with decreasing gestational age, with the white matter predominantly affected. Developmental immaturity in the cerebral circulation, including ongoing angiogenesis and vasoregulatory immaturity, plays a major role in the severity and pattern of preterm brain injury. Prevention of this injury requires insight into pathogenesis. Cerebral blood flow (CBF) is low in the preterm white matter, which also has blunted vasoreactivity compared with other brain regions. Vasoreactivity in the preterm brain to cerebral perfusion pressure, oxygen, carbon dioxide, and neuronal metabolism is also immature. This could be related to immaturity of both the vasculature and vasoactive signaling. Other pathologies arising from preterm birth and the neonatal intensive care environment itself may contribute to impaired vasoreactivity and ineffective CBF regulation, resulting in the marked variations in cerebral hemodynamics reported both within and between infants depending on their clinical condition. Many gaps exist in our understanding of how neonatal treatment procedures and medications have an impact on cerebral hemodynamics and preterm brain injury. Future research directions for neuroprotective strategies include establishing cotside, real-time clinical reference values for cerebral hemodynamics and vasoregulatory capacity and to demonstrate that these thresholds improve long-term outcomes for the preterm infant. In addition, stimulation of vascular development and repair with growth factor and cell-based therapies also hold promise.
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Affiliation(s)
- Nadine Brew
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and
| | - David Walker
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Flora Y Wong
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and Monash Newborn, Monash Medical Centre, Melbourne, Victoria, Australia; and Department of Pediatrics, Monash University, Melbourne, Victoria, Australia
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20
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Ainslie PN, Brassard P. Why is the neural control of cerebral autoregulation so controversial? F1000PRIME REPORTS 2014; 6:14. [PMID: 24669295 PMCID: PMC3944747 DOI: 10.12703/p6-14] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cerebral autoregulation refers to the mechanisms that act to keep cerebral blood flow (CBF) constant during changes in blood pressure. The mechanisms of cerebral autoregulation, especially in humans, are poorly understood but are undoubtedly multifactorial and likely reflect many redundant pathways that potentially differ between species. Whether sympathetic nervous activity influences CBF and/or cerebral autoregulation in humans remains controversial. Following a brief introduction to cerebral autoregulation, this review highlights the likely reasons behind the controversy of the neural control of cerebral autoregulation. Finally, suggestions are provided for further studies to improve the understanding of the neural control of CBF regulation.
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Affiliation(s)
- Philip N. Ainslie
- Center for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia – OkanaganKelowna, British ColumbiaCanada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université LavalQuébecCanada
- Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de QuébecQuébecCanada
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21
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Willie CK, Tzeng YC, Fisher JA, Ainslie PN. Integrative regulation of human brain blood flow. J Physiol 2014; 592:841-59. [PMID: 24396059 PMCID: PMC3948549 DOI: 10.1113/jphysiol.2013.268953] [Citation(s) in RCA: 579] [Impact Index Per Article: 57.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/24/2013] [Indexed: 02/06/2023] Open
Abstract
Herein, we review mechanisms regulating cerebral blood flow (CBF), with specific focus on humans. We revisit important concepts from the older literature and describe the interaction of various mechanisms of cerebrovascular control. We amalgamate this broad scope of information into a brief review, rather than detailing any one mechanism or area of research. The relationship between regulatory mechanisms is emphasized, but the following three broad categories of control are explicated: (1) the effect of blood gases and neuronal metabolism on CBF; (2) buffering of CBF with changes in blood pressure, termed cerebral autoregulation; and (3) the role of the autonomic nervous system in CBF regulation. With respect to these control mechanisms, we provide evidence against several canonized paradigms of CBF control. Specifically, we corroborate the following four key theses: (1) that cerebral autoregulation does not maintain constant perfusion through a mean arterial pressure range of 60-150 mmHg; (2) that there is important stimulatory synergism and regulatory interdependence of arterial blood gases and blood pressure on CBF regulation; (3) that cerebral autoregulation and cerebrovascular sensitivity to changes in arterial blood gases are not modulated solely at the pial arterioles; and (4) that neurogenic control of the cerebral vasculature is an important player in autoregulatory function and, crucially, acts to buffer surges in perfusion pressure. Finally, we summarize the state of our knowledge with respect to these areas, outline important gaps in the literature and suggest avenues for future research.
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Affiliation(s)
- Christopher K Willie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada V1V 1V7.
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22
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Wong F, Yiallourou SR, Odoi A, Browne P, Walker AM, Horne RSC. Cerebrovascular control is altered in healthy term infants when they sleep prone. Sleep 2013; 36:1911-8. [PMID: 24293766 PMCID: PMC3825441 DOI: 10.5665/sleep.3228] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Sudden infant death syndrome (SIDS) is a leading cause of infant death, and prone sleeping is the major risk factor. Prone sleeping impairs arousal from sleep and cardiovascular control in infants at 2-3 months, coinciding with the highest risk period for SIDS. We hypothesized that prone sleeping would also alter cerebrovascular control, and aimed to test this hypothesis by examining responses of cerebral oxygenation to head-up tilts (HUTs) over the first 6 months after birth. STUDY DESIGN AND PARTICIPANTS Seventeen healthy full-term infants were studied at 2-4 weeks, 2-3 months, and 5-6 months of age using daytime polysomnography, with the additional measurements of blood pressure (BP, Finometer™, Finometer Medical Systems, The Netherlands) and cerebral tissue oxygenation index (TOI, NIRO 200, Hamamatsu Photonics KK, Japan). HUTs were performed in active sleep (AS) and quiet sleep (QS) in both prone and supine positions. RESULTS When infants slept in the prone position, a sustained increase in TOI (P < 0.05) occurred following HUTs, except in QS at 2-3 months when TOI was unchanged. BP was either unchanged or fell below baseline during the sustained TOI increase, signifying cerebro-vasodilatation. In contrast, when infants slept supine, TOI did not change after HUTs, except in QS at 2-3 and 5-6 months when TOI dropped below baseline (P < 0.05). CONCLUSIONS When infants slept in the prone position, cerebral arterial vasodilation and increased cerebral oxygenation occurred during head-up tilts, possibly as a protection against cerebral hypoxia. Absence of the vasodilatory response during quiet sleep at 2-3 months possibly underpins the decreased arousability from sleep and increased risk for sudden infant death syndrome at this age.
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Affiliation(s)
- Flora Wong
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
- Monash Newborn, Monash Medical Centre, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Stephanie R. Yiallourou
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
| | - Alexsandria Odoi
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
| | - Pamela Browne
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
| | - Adrian M. Walker
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
| | - Rosemary S. C. Horne
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
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23
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Beuchée A, Hernández AI, Duvareille C, Daniel D, Samson N, Pladys P, Praud JP. Influence of hypoxia and hypercapnia on sleep state-dependent heart rate variability behavior in newborn lambs. Sleep 2012; 35:1541-9. [PMID: 23115403 DOI: 10.5665/sleep.2206] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Although hypercapnia and/or hypoxia are frequently present during chronic lung disease of infancy and have also been implicated in sudden infant death syndrome (SIDS), their effect on cardiac autonomic regulation remains unclear. The authors' goal is to test that hypercapnia and hypoxia alter sleep-wake cycle-dependent heart rate variability (HRV) in the neonatal period. DESIGN Experimental study measuring HRV during sleep states in lambs randomly exposed to hypercapnia, hypoxia, or air. SETTING University center for perinatal research in ovines (Sherbrooke, Canada). INSERM-university research unit for signal processing (Rennes, France). PARTICIPANTS Six nonsedated, full-term lambs. INTERVENTIONS Each lamb underwent polysomnographic recordings while in a chamber flowed with either air or 21% O(2) + 5% CO(2) (hypercapnia) or 10% O(2) + 0% CO(2) (hypoxia) on day 3, 4, and 5 of postnatal age. MEASUREMENTS AND RESULTS Hypercapnia increased the time spent in wakefulness and hypoxia the time spent in quiet sleep (QS). The state of alertness was the major determinant of HRV characterized with linear or nonlinear methods. Compared with QS, active sleep (AS) was associated with an overall increase in HRV magnitude and short-term self-similarity and a decrease in entropy of cardiac cycle length in air. This AS-related HRV pattern persisted in hypercapnia and was even more pronounced in hypoxia. CONCLUSION Enhancement of AS-related sympathovagal coactivation in hypoxia, together with increased heart rate regularity, may be evidence that AS + hypoxia represent a particularly vulnerable state in early life. This should be kept in mind when deciding the optimal arterial oxygenation target in newborns and when investigating the potential involvement of hypoxia in SIDS pathogenesis.
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Winklewski PJ, Frydrychowski AF. Cerebral blood flow, sympathetic nerve activity and stroke risk in obstructive sleep apnoea. Is there a direct link? Blood Press 2012; 22:27-33. [PMID: 23004573 DOI: 10.3109/08037051.2012.701407] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Obstructive sleep apnoea (OSA) is significantly associated with the risk of stroke, and this association is independent of other risk factors, including hypertension, atrial fibrillation and diabetes mellitus. Therefore, additional pathogenic mechanisms may exist, which contribute to the increased risk of stroke. OSA is characterized by prolonged sympathetic overactivity; however the role of the sympathetic nervous system in regulating cerebral circulation remains a matter of controversy. Converging data indicate that brain perfusion is significantly distorted in OSA, with reported decreases in cerebral blood flow as well as intermittent surges in blood pressure and cerebral blood flow velocity. Based on recent research, there is accumulating evidence that sympathetic nerve activity is an important element in brain protection against excessive increases in perfusion pressure during blood pressure surges and flow during rapid eye movement sleep. The aim of this article was to review: (i) the current physiological knowledge related to the role of the sympathetic system in the regulation of cerebral blood flow, (ii) how the influence of the sympathetic system on cerebral vessels is affected by apnoea (increased PaCO(2)) and (iii) the potential significance of the pathological sympathetic system/PaCO(2) interplay in OSA. Sympathetic system seems to be at least partially involved in pathogenesis of distorted haemodynamics and stroke in OSA patients. However, there are still several open questions that need to be addressed before the effective therapeutic strategies can be implemented.
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Affiliation(s)
- Pawel J Winklewski
- Institute of Human Physiology, Faculty of Health Sciences, Medical University of Gdansk, Tuwima Str. 15, 80-210 Gdansk, Poland.
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25
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Wang Z, Wang X, Yuan W, Jiang D. Degenerative pathological irritations to cervical PLL may play a role in presenting sympathetic symptoms. Med Hypotheses 2011; 77:921-3. [PMID: 21890278 DOI: 10.1016/j.mehy.2011.08.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 08/06/2011] [Indexed: 02/08/2023]
Abstract
The mechanism of cervical vertigo remains unknown. Stimulation of arterial vertebralis caused by osteophyte of the Luschka joint or segmental instability of the cervical spine was considered to be a potential factor contributing to it. Years of studies found that the ischemia of the vertebral artery is not directly correlated with the clinical symptoms of vertigo, and can not be used to explain cervical vertigo as a sole reason. As proven by clinical practical experience, the routine anterior cervical decompression and fusion (ACDF) procedure, in which the degenerative disc and posterior longitudinal ligament (PLL) were often removed, shows positive results for elimination of the sympathetic symptoms. In this article, we hypothesize that: (1) there are sympathetic nerve postganglionic fibers distributed in the PLL or discs; (2) pathological changes secondary to degeneration of the intervertebral disc may cause irritation of sympathetic nerve fibers in PLL or discs, leading to sympathetic symptoms via certain pathways; (3) removal of the PLL or stabilization of the segment which decreases the irritation to PLL will help to eliminate the sympathetic symptoms.
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Affiliation(s)
- Zhanchao Wang
- Department of Orthopedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
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26
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Willie CK, Colino FL, Bailey DM, Tzeng YC, Binsted G, Jones LW, Haykowsky MJ, Bellapart J, Ogoh S, Smith KJ, Smirl JD, Day TA, Lucas SJ, Eller LK, Ainslie PN. Utility of transcranial Doppler ultrasound for the integrative assessment of cerebrovascular function. J Neurosci Methods 2011; 196:221-37. [PMID: 21276818 DOI: 10.1016/j.jneumeth.2011.01.011] [Citation(s) in RCA: 406] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 01/05/2011] [Accepted: 01/06/2011] [Indexed: 01/05/2023]
Abstract
There is considerable utility in the use of transcranial Doppler ultrasound (TCD) to assess cerebrovascular function. The brain is unique in its high energy and oxygen demand but limited capacity for energy storage that necessitates an effective means of regional blood delivery. The relative low cost, ease-of-use, non-invasiveness, and excellent temporal resolution of TCD make it an ideal tool for the examination of cerebrovascular function in both research and clinical settings. TCD is an efficient tool to access blood velocities within the cerebral vessels, cerebral autoregulation, cerebrovascular reactivity to CO(2), and neurovascular coupling, in both physiological states and in pathological conditions such as stroke and head trauma. In this review, we provide: (1) an overview of TCD methodology with respect to other techniques; (2) a methodological synopsis of the cerebrovascular exam using TCD; (3) an overview of the physiological mechanisms involved in regulation of the cerebral blood flow; (4) the utility of TCD for assessment of cerebrovascular pathology; and (5) recommendations for the assessment of four critical and complimentary aspects of cerebrovascular function: intra-cranial blood flow velocity, cerebral autoregulation, cerebral reactivity, and neurovascular coupling. The integration of these regulatory mechanisms from an integrated systems perspective is discussed, and future research directions are explored.
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Affiliation(s)
- C K Willie
- Department of Human Kinetics, Faculty of Health and Social Development, University of British Columbia Okanagan, 3333 University Way, Kelowna, BC, Canada V1V 1V7.
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27
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Ainslie PN, Duffin J. Integration of cerebrovascular CO2 reactivity and chemoreflex control of breathing: mechanisms of regulation, measurement, and interpretation. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1473-95. [PMID: 19211719 DOI: 10.1152/ajpregu.91008.2008] [Citation(s) in RCA: 398] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cerebral blood flow (CBF) and its distribution are highly sensitive to changes in the partial pressure of arterial CO(2) (Pa(CO(2))). This physiological response, termed cerebrovascular CO(2) reactivity, is a vital homeostatic function that helps regulate and maintain central pH and, therefore, affects the respiratory central chemoreceptor stimulus. CBF increases with hypercapnia to wash out CO(2) from brain tissue, thereby attenuating the rise in central Pco(2), whereas hypocapnia causes cerebral vasoconstriction, which reduces CBF and attenuates the fall of brain tissue Pco(2). Cerebrovascular reactivity and ventilatory response to Pa(CO(2)) are therefore tightly linked, so that the regulation of CBF has an important role in stabilizing breathing during fluctuating levels of chemical stimuli. Indeed, recent reports indicate that cerebrovascular responsiveness to CO(2), primarily via its effects at the level of the central chemoreceptors, is an important determinant of eupneic and hypercapnic ventilatory responsiveness in otherwise healthy humans during wakefulness, sleep, and exercise and at high altitude. In particular, reductions in cerebrovascular responsiveness to CO(2) that provoke an increase in the gain of the chemoreflex control of breathing may underpin breathing instability during central sleep apnea in patients with congestive heart failure and on ascent to high altitude. In this review, we summarize the major factors that regulate CBF to emphasize the integrated mechanisms, in addition to Pa(CO(2)), that control CBF. We discuss in detail the assessment and interpretation of cerebrovascular reactivity to CO(2). Next, we provide a detailed update on the integration of the role of cerebrovascular CO(2) reactivity and CBF in regulation of chemoreflex control of breathing in health and disease. Finally, we describe the use of a newly developed steady-state modeling approach to examine the effects of changes in CBF on the chemoreflex control of breathing and suggest avenues for future research.
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Affiliation(s)
- Philip N Ainslie
- Department of Physiology, University of Otago, Dunedin, New Zealand.
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28
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Ainslie PN. Have a safe night: intimate protection against cerebral hyperperfusion during REM sleep. J Appl Physiol (1985) 2009; 106:1031-3. [PMID: 19196917 DOI: 10.1152/japplphysiol.00091.2009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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