Computerised transient hyperaemic response test—A method for the assessment of cerebral autoregulation

Smielewski, Peter; Czosnyka, Marek; Iyer, Vijay; Piechnik, Stefan K.; Whitehouse, Helen; Pickard, John D.

doi:10.1016/0301-5629(94)00154-6

Cited by 50 publications

(31 citation statements)

References 35 publications

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“…These methods have been used to assess the integrity of cerebral autoregulation [1, 4]and may help to clarify the prognosis in certain clinical situations, e.g. after head injury and subarachnoid haemorrhage [3, 5, 6, 7]. We are unaware of any reports of transient cerebral hyperaemia following cardiac arrhythmias in humans.…”

Section: Introductionmentioning

confidence: 97%

“…Transient hyperaemia in the cerebral circulation may be detected by measuring changes in middle cerebral blood flow velocities with transcranial Doppler ultrasound following brief ipsilateral common carotid artery compressions and rapid thigh cuff deflations [1, 2, 3, 4]. These methods have been used to assess the integrity of cerebral autoregulation [1, 4]and may help to clarify the prognosis in certain clinical situations, e.g.…”

Section: Introductionmentioning

confidence: 99%

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A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

Carey¹,

Eames²,

Panerai

et al. 2000

Cerebrovasc Dis

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Transient cerebral hyperaemia following an arrhythmia has not been previously demonstrated in humans. We report the effects of head-up tilt on a 78-year-old man with neurocardiogenic syncope. During tilt, an asymptomatic arrhythmia caused arterial blood pressure and transcranial Doppler-recorded cerebral blood flow velocity to fall markedly. Upon spontaneous resumption of sinus rhythm, cerebral blood flow velocity increased to values greater than those prior to the arrhythmia. This occurred prior to a full recovery of arterial blood pressure, indicating spontaneous transisent hyperaemia. Pressure-flow velocity graphs support current methods of measuring critical closing pressure and demonstrate a rise in critical closing and a fall in resistance-area product after the arrhythmia.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

Carey¹,

Eames²,

Panerai

et al. 2000

Cerebrovasc Dis

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“…It is a recognized and simple method of testing autoregulation in vivo. 2,6,8,[10][11][12][13][14][15][16][17][18] It is directly proportional to the static rate of autoregulation, which is the 'gold standard' for measuring autoregulation, 15 and it has been shown to be predictive of DCI after SAH. 2,6 However, other ways of measuring autoregulation that do not require physical or pharmacological blood pressure stimulation have been described.…”

Section: Introductionmentioning

confidence: 99%

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Budohoski

Czosnyka

Smielewski

et al. 2012

J Cereb Blood Flow Metab

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In patients after subarachnoid hemorrhage (SAH) failure of cerebral autoregulation is associated with delayed cerebral ischemia (DCI). Various methods of assessing autoregulation are available, but their predictive values remain unknown. We characterize the relationship between different indices of autoregulation. Patients with SAH within 5 days were included in a prospective study. The relationship between three indices of autoregulation was analyzed: two indices calculated using spontaneous blood pressure fluctuations, Sxa (based on transcranial Doppler) and TOxa (based on near-infrared spectroscopy); and transient hyperemic response test (THRT) where a brief compression of the common carotid artery is used. The predictive value of indices was assessed using data from the first 5 days. Overall there was only moderate correlation between indices. However, both Sxa and TOxa showed good accuracy in predicting impaired autoregulation evidenced by a negative THRT (area under the curve (AUC): 0.788, 95% CI: 0.723 to 0.854 and AUC: 0.827, 95% CI: 0.769 to 0.885, respectively). All indices proved accurate in predicting DCI when 0-to 5-day data were used (AUC: 0.801, 95% CI: 0.660 to 0.942; AUC: 0.857, 95% CI: 0.731 to 0.984, AUC: 0.796, 95% CI: 0.658 to 0.934 for THRT, Sxa, and TOxa, respectively). Combining all three indices had 100% specificity for predicting DCI. While multiple colinearities exist between the assessed methods, multimodal monitoring of cerebral autoregulation can aid in predicting DCI.

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“…Dynamic CA is impaired in a variety of disease states, including post-head injury disorders, subarachnoid hemorrhage, acute ischemic stroke, and carotid artery disease. [7][8][9][10][11][12] It has been suggested that static and dynamic CA may have different control mechanisms and that dynamic CA may be more susceptible to damage in pathological states, 13 as seen after acute ischemic stroke. 11 Since disease states likely to affect CA are more common in the elderly, it is important to know whether aging per se affects CA.…”

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confidence: 99%

Dynamic Cerebral Autoregulation Is Unaffected by Aging

Carey

Eames

Blake

et al. 2000

Stroke

120

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Background and Purpose-Normal aging is associated with marked changes in the cardiovascular and cerebrovascular systems. Although cerebral autoregulation (CA) is impaired in certain disease states, the effect of age per se on dynamic CA in humans is unknown and the focus of this study. Methods-Twenty-seven young subjects (Յ40 years) and 27 older subjects (Ն55 years), matched for sex and systolic blood pressure (BP), underwent measurement of cerebral blood flow velocity by transcranial Doppler ultrasound and noninvasive beat-to-beat arterial BP measurement during induced and spontaneous dynamic BP stimuli. A standard dynamic autoregulatory index (ARI) was derived for each spontaneous and induced dynamic BP stimulus to include the step response, as well as cardiac baroreceptor sensitivity (BRS), for the 2 groups. Results-The mean age of the young group was 29Ϯ5 years, and that of the older group was 68Ϯ5 years. Cardiac BRS was reduced in the older group (8.6Ϯ4.5 versus 16.9Ϯ8.8 ms/mm Hg; PϽ0.0001). However, no age-related differences were demonstrated in step response plots or in ARI values for any pressor or depressor dynamic BP stimulus (Pϭ0.62), with mean ARI values for all stimuli combined being 4.9Ϯ1.8 for the young group and 5.0Ϯ2.3 for the older group. Conclusions-Although increasing age is associated with a decrease in cardiac BRS, dynamic CA, as assessed by step response analysis as well as cerebral blood flow responses to transient and induced BP stimuli, is unaffected by aging.

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Computerised transient hyperaemic response test—A method for the assessment of cerebral autoregulation

Cited by 50 publications

References 35 publications

A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

A Case of Arrhythmia-Induced Transient Cerebral Hyperaemia

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Dynamic Cerebral Autoregulation Is Unaffected by Aging

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