Search results for " cerebral autoregulation"

showing 5 items of 5 documents

Transcranial Doppler ultrasound study of the effects of nitrous oxide on cerebral autoregulation during neurosurgical anesthesia: a randomized contro…

2003

Object. Nitrous oxide has an adverse effect on cerebrovascular hemodynamics. Increased intracranial pressure, cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and reduced autoregulation indices have been reported, but their magnitudes are still being debated. This study was designed to evaluate the effect of N2O on CBF and autoregulatory indexes during N2O—sevoflurane anesthesia in a prospective randomized controlled series of patients. Methods. Two groups of 20 patients were studied on the basis of the use of N2O in the anesthetic gas mixture. The transient hyperemic response test, which relies on transcranial Doppler ultrasound techniques, was used to assess cerebral hemo…

AdultMaleDuplex ultrasonographyAdolescentUltrasonography Doppler TranscranialNitrous OxideHemodynamicsTranscranial Doppler cerebral autoregulation neurosurgical patientsAnesthesia GeneralCerebral autoregulationNeurosurgical ProceduresmedicineHomeostasisHumansAutoregulationIntracranial pressurebusiness.industrySettore MED/27 - NeurochirurgiaBrainMiddle AgedEchoencephalographyTranscranial DopplerCerebral blood flowAnesthesiaAnestheticFemalebusinessBlood Flow Velocitymedicine.drugJournal of neurosurgery
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Spectral decomposition of cerebrovascular and cardiovascular interactions in patients prone to postural syncope and healthy controls.

2022

We present a framework for the linear parametric analysis of pairwise interactions in bivariate time series in the time and frequency domains, which allows the evaluation of total, causal and instantaneous interactions and connects time- and frequency-domain measures. The framework is applied to physiological time series to investigate the cerebrovascular regulation from the variability of mean cerebral blood flow velocity (CBFV) and mean arterial pressure (MAP), and the cardiovascular regulation from the variability of heart period (HP) and systolic arterial pressure (SAP). We analyze time series acquired at rest and during the early and late phase of head-up tilt in subjects developing or…

Endocrine and Autonomic SystemsTime series analysisBlood PressureHeartBaroreflexCardiovascular SystemSyncopeCerebral autoregulationCellular and Molecular NeuroscienceHeart RateAutoregressive modelsCardiovascular controlCerebrovascular CirculationGranger causalitySettore ING-INF/06 - Bioingegneria Elettronica e InformaticaHumansNeurology (clinical)Spectral decompositionAutoregressive models; Cardiovascular control; Cerebral autoregulation; Granger causality; Spectral decomposition; Time series analysis;Autonomic neuroscience : basicclinical
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Nonlinear effects of respiration on the crosstalk between cardiovascular and cerebrovascular control systems.

2016

Cardiovascular and cerebrovascular regulatory systems are vital control mechanisms responsible for guaranteeing homeostasis and are affected by respiration. This work proposes the investigation of cardiovascular and cerebrovascular control systems and the nonlinear influences of respiration on both regulations through joint symbolic analysis (JSA), conditioned or unconditioned on respiration. Interactions between cardiovascular and cerebrovascular regulatory systems were evaluated as well by performing correlation analysis between JSA indexes describing the two control systems. Heart period, systolic and mean arterial pressure, mean cerebral blood flow velocity and respiration were acquired…

Mean arterial pressuremedicine.medical_specialtySupine positionGeneral Mathematics0206 medical engineeringGeneral Physics and Astronomy02 engineering and technology030204 cardiovascular system & hematologyBaroreflexCerebral autoregulationCardiovascular System03 medical and health sciencesPhysics and Astronomy (all)0302 clinical medicineEngineering (all)Conditional joint symbolic analysiInternal medicineRespirationmedicineHeart rate variabilityAutonomic nervous system; Baroreflex; Cerebral autoregulation; Conditional joint symbolic analysis; Head-up tilt; Heart rate variability; Mathematics (all); Physics and Astronomy (all); Engineering (all)Autonomic nervous systemMathematics (all)Heart rate variabilitybusiness.industryAutonomic nervous system; Baroreflex; Cerebral autoregulation; Conditional joint symbolic analysis; Head-up tilt; Heart rate variability; Mathematics (all); Engineering (all); Physics and Astronomy (all)Head-up tiltGeneral EngineeringBaroreflex020601 biomedical engineeringCerebral autoregulationAutonomic nervous systemCerebral blood flowConditional joint symbolic analysisSettore ING-INF/06 - Bioingegneria Elettronica E InformaticaCardiologybusinessPhilosophical transactions. Series A, Mathematical, physical, and engineering sciences
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Update on mechanism and therapeutic implications of spinal cord stimulation and cerebral hemodynamics: A narrative review

2017

Spinal cord stimulation (SCS) is well known for its early role in the management of chronic pain, mainly failed back surgery syndrome (FBSS), spasticity, and bowel and bladder dysfunction. In more recent years, SCS has been proposed for patients suffering from refractory angina or peripheral vasculopathies in order to gain symptom relief, thus indicating some hemodynamic effect on the peripheral circulation. Taking into account this scientific observation, since the late1980s, researchers have started to investigate the potential effect of SCS on cerebral blood flow (CBF) regulation and its possible application in certain pathological settings dealing with vascular pattern dysfunction, such…

Subarachnoid hemorrhage030204 cardiovascular system & hematologyCerebral autoregulationBrain IschemiaBrain ischemia03 medical and health sciences0302 clinical medicineAnimalsHomeostasisHumansVasospasm IntracranialMedicineSpasticitySympathectomyBrain injuryStrokeBrain Neoplasmsbusiness.industrySettore MED/27 - NeurochirurgiaBrain injury; Cerebral autoregulation; Cerebral blood flow; Functional sympathectomy; Spinal cord stimulation; Stroke; Vasospasm; Surgery; Neurology (clinical)HemodynamicsChronic painVasospasmFunctional sympathectomySubarachnoid HemorrhageCerebral blood flowmedicine.diseaseVasospasmCerebral autoregulationStrokenervous systemCerebral blood flowSpinal cord stimulationBrain InjuriesCerebrovascular CirculationAnesthesiaSurgeryNeurology (clinical)medicine.symptombusiness030217 neurology & neurosurgery
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Use of middle cerebral velocity and blood pressure for the analysis of cerebral autoregulation at various frequencies: The coherence index

1998

A common component in many protocols for the evaluation of cerebral autoregulation is the comparison of transcranial Doppler ultrasound (TCD) velocities with blood pressure recordings, in which correlations between these two signals correspond to impaired autoregulation. With long data sets and complicated paradigms, however, visual inspection alone cannot adequately distinguish random coincidence from consistent correlation in a statistically valid fashion. We suggest and illustrate the use of the coherence index for this purpose. To illustrate this technique, long-term recordings of TCD velocity and blood pressure were obtained from 6 normal subjects and using 23 data segments from 8 pati…

Subarachnoid hemorrhageUltrasonography Doppler TranscranialHemodynamicsBlood PressureCerebral autoregulationCorrelationNuclear magnetic resonanceReference ValuesmedicineTidal VolumeHomeostasisHumansAutoregulationTranscranial doppler cerebral autoregulationMathematicsFourier AnalysisSettore MED/27 - NeurochirurgiaGeneral MedicineCoherence (statistics)Cerebral ArteriesSubarachnoid Hemorrhagemedicine.diseaseTranscranial DopplerPlethysmographyBlood pressureNeurologyAnesthesiaNeurology (clinical)Blood Flow VelocitySoftware
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