Monitoring cerebral autoregulation after head injury. Which component of transcranial Doppler flow velocity is optimal?

Budohoski, Karol P.; Reinhard, Matthias; Aries, Marcel; Czosnyka, Zofia; Smielewski, Peter; Pickard, John D.; Kirkpatrick, Peter J.; Czosnyka, Marek

doi:10.1007/s12028-011-9572-1

Cited by 84 publications

(70 citation statements)

References 27 publications

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“…35 However, a cohort study of 300 patients with head injury showed that Sxa had a stronger association with outcome than Mxa. 31 Relationship of Continuous Indices, Sxa and TOxa, with Transient Hyperemic Response Ratio Both Sxa and TOxa showed good accuracy for predicting impaired autoregulation as seen by a THRR of p1.09, without significant differences between the two methods. However, the correlations between THRR and Sxa and TOxa were relatively poor, in keeping with previous reports from head injury.…”

Section: Methodological Considerationsmentioning

confidence: 93%

“…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%

“…Previous data suggest that blood pressure-based indices correlate well with cerebral perfusion pressure (CPP) based indices. 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.…”

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: 93%

Section: Methodological Considerationsmentioning

confidence: 99%

Section: Methodological Considerationsmentioning

confidence: 99%

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

Section: Calculation Of Hemodynamic Parametersmentioning

confidence: 99%

See 3 more Smart Citations

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Budohoski

Czosnyka

Smielewski

et al. 2012

J Cereb Blood Flow Metab

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Transcranial Doppler: a stethoscope for the brain‐neurocritical care use

Robba

Cardim

Sekhon

et al. 2017

J of Neuroscience Research

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Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside monitoring technique that can evaluate cerebral blood flow hemodynamics in the intracranial arterial vasculature. TCD allows assessment of linear cerebral blood flow velocity, with a high temporal resolution and is inexpensive, reproducible, and portable. The aim of this review is to provide an overview of the most commonly used TCD derived signals and measurements used commonly in neurocritical care. We describe both basic (flow velocity, pulsatility index) and advanced concepts, including critical closing pressure, wall tension, autoregulation, noninvasive intracranial pressure, brain compliance, and cerebrovascular time constant; we also describe the clinical applications of TCD to highlight their utility in the diagnosis and monitoring of cerebrovascular diseases as the "stethoscope for the brain."

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Ultrasound Imaging for Traumatic Brain Injury

Shin

Huisman

Hwang

2018

J of Ultrasound Medicine

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Traumatic brain injury (TBI) is challenging to assess even with recent advancements in computed tomography and magnetic resonance imaging. Ultrasound (US) imaging has previously been less utilized in TBI compared to conventional imaging because of limited resolution in the intracranial space. However, there have been substantial improvements in contrast-enhanced US and development of novel techniques such as intravascular US. Also, continued research provides further insight into cerebrovascular parameters from transcranial Doppler imaging. These advancements in US imaging provides the community of TBI imaging researchers and clinicians new opportunities in clinically monitoring and understanding the pathologic mechanisms of TBI.

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Monitoring cerebral autoregulation after head injury. Which component of transcranial Doppler flow velocity is optimal?

Abstract: Systolic flow indices (Sx and Sxa) demonstrated a stronger association with outcome than the mean flow indices (Mx and Mxa), irrespective of whether CPP or ABP was used for calculation.

Cited by 84 publications

References 27 publications

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Transcranial Doppler: a stethoscope for the brain‐neurocritical care use

Ultrasound Imaging for Traumatic Brain Injury

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