Monitoring of cerebral autoregulation in head-injured patients

Czosnyka, Marek; Smielewski, Peter; Kirkpatrick, Peter J.; Menon, Danish; Pickard, J. D.

doi:10.1097/00008506-199704000-00021

Cited by 375 publications

(198 citation statements)

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“…Furthermore, THRT in prospective observational studies was shown to be useful in predicting clinical deterioration after SAH. 2,6 However, while clinical and experimental data exist supporting the validity of Sxa and TOxa, 13,23,25,31,32,34 neither index has been evaluated for its power to predict DCI. The mean flow index, Mx, which is derived from mean FV and CPP and its noninvasive version, Mxa, where ABP is used instead of CPP, have been previously investigated in patients with SAH.…”

Section: Methodological Considerationsmentioning

confidence: 99%

“…3,35 In the present study, we have used an alternative index derived from systolic values of FV as previously described. 13,31,32 In one study of 32 patients with SAH changes in autoregulation during vasospasm were identified more accurately with Mx than with Sx. 35 However, a cohort study of 300 patients with head injury showed that Sxa had a stronger association with outcome than Mxa.…”

Section: Methodological Considerationsmentioning

confidence: 99%

“…(2) TCD-based autoregulation, Sxa, was calculated as a moving, linear correlation coefficient between values of systolic FV and ABP from a 300-second window with an averaging period of 10 seconds. 31,32 The minimum monitoring time required for results to be considered meaningful was 30 minutes. (3) Near-infrared spectroscopy-based autoregulation, TOxa, was calculated as a moving, linear correlation coefficient between values of tissue oxygenation index and ABP from a 300-second window with an update every 10 seconds.…”

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

“…25,31,33 The physiologic basis for the correlation coefficient methodology has been described elsewhere. 25,32 Briefly, a passive transmission of ABP fluctuations to FV and tissue oxygenation index, respectively, is suggestive of passive pressure-flow relationship and therefore impaired autoregulation. In such cases, the calculated autoregulatory indices will be positive.…”

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

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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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Section: Methodological Considerationsmentioning

confidence: 99%

Section: Methodological Considerationsmentioning

confidence: 99%

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

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Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Budohoski

Czosnyka

Smielewski

et al. 2012

J Cereb Blood Flow Metab

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“…Traditionally, transcranial Doppler (TCD) ultrasound is used to measure cerebral blood flow velocity (CBFV) continuously at the bedside to determine dynamic autoregulation [17,18]. Limitations of this noninvasive technique are the assumption of a constant intracerebral vessel caliber, not taking into account the angle of vessel insonation and difficulties with obtaining long and stable recordings.…”

Section: Concepts Of Static and Dynamic Autoregulationmentioning

confidence: 99%

Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature

Kooi¹,

Verhagen

Elting

et al. 2017

Expert Review of Neurotherapeutics

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(2017) Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature, Expert Review of Neurotherapeutics, 17:8, 801-818, DOI: 10.1080/14737175.2017 Introduction:The preterm born infant's ability to regulate its cerebral blood flow (CBF) is crucial in preventing secondary ischemic and hemorrhagic damage in the developing brain. The relationship between arterial blood pressure (ABP) and CBF estimates, such as regional cerebral oxygenation as measured by near-infrared spectroscopy (NIRS), is an attractive option for continuous non-invasive assessment of cerebrovascular autoregulation. Areas covered: The authors performed a literature search to provide an overview of the current literature on various current clinical practices and methods to measure cerebrovascular autoregulation in the preterm infant by NIRS. The authors focused on various aspects: Characteristics of patient cohorts, surrogate measures for cerebral perfusion pressure, NIRS devices and their accompanying parameters, definitions for impaired cerebrovascular autoregulation, methods of measurements and clinical implications. Expert commentary: Autoregulation research in preterm infants has reported many methods for measuring autoregulation using different mathematical models, signal processing and data requirements. At present, it remains unclear which NIRS signals and algorithms should be used that result in the most accurate and clinically relevant assessment of cerebrovascular autoregulation. Future studies should focus on optimizing strategies for cerebrovascular autoregulation assessment in preterm infants in order to develop autoregulation-based cerebral perfusion treatment strategies. ARTICLE HISTORY

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Novel Applications of Ultrasound Vascular Imaging

Azevedo

Castro

2013

Vascular Imaging of the Central Nervous System

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Monitoring of cerebral autoregulation in head-injured patients

Cited by 375 publications

References 0 publications

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature

Novel Applications of Ultrasound Vascular Imaging

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