Implementation of non-invasive brain physiological monitoring concepts

Ragauskas, Arminas; Daubaris, Gediminas; Ragaišis, Vytautas; Petkus, Vytautas

doi:10.1016/s1350-4533(03)00082-1

Cited by 36 publications

(37 citation statements)

References 16 publications

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“…The median pre-intubation Glasgow Coma Scale (GCS) score of the patients was 6 (range, [3][4][5][6][7][8][9][10][11][12][13][14]. The data included daily recordings of ABP, ICP, and TCD, in a total of 66 recordings.…”

Section: Patient Populationmentioning

confidence: 99%

“…Several methods for noninvasive assessment of ICP (nICP) have been described so far: transcranial Doppler ultrasonography (TCD) to measure cerebral blood flow velocity indices 2 ; skull vibrations 3 ; brain tissue resonance 4 or transcranial time of flight 5 ; venous ophthalmodynamometry 6 ; optic nerve sheath diameter assessment (ONSD) 7 ; sensing tympanic membrane displacement (TMD) 8,9 ; otoacoustic emissions 10 ; magnetic resonance imaging to estimate intracranial compliance 11 ; ultrasound-guided eyeball compression 12 ; and recordings of visual evoked potentials. 13 These methods are better suited for one-point assessment of instant value of ICP rather than continuous monitoring.…”

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confidence: 99%

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Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods

Cardim

Robba

Donnelly

et al. 2016

Journal of Neurotrauma

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Elevation of intracranial pressure (ICP) may occur in many diseases, and therefore the ability to measure it noninvasively would be useful. Flow velocity signals from transcranial Doppler (TCD) have been used to estimate ICP; however, the relative accuracy of these methods is unclear. This study aimed to compare four previously described TCD-based methods with directly measured ICP in a prospective cohort of traumatic brain-injured patients. Noninvasive ICP (nICP) was obtained using the following methods: 1) a mathematical ''black-box'' model based on interaction between TCD and arterial blood pressure (nICP_BB); 2) based on diastolic flow velocity (nICP_FVd); 3) based on critical closing pressure (nICP_CrCP); and 4) based on TCD-derived pulsatility index (nICP_PI). In time domain, for recordings including spontaneous changes in ICP greater than 7 mm Hg, nICP_PI showed the best correlation with measured ICP (R = 0.61). Considering every TCD recording as an independent event, nICP_BB generally showed to be the best estimator of measured ICP (R = 0.39; p < 0.05; 95% confidence interval [CI] = 9.94 mm Hg; area under the curve [AUC] = 0.66; p < 0.05). For nICP_FVd, although it presented similar correlation coefficient to nICP_BB and marginally better AUC (0.70; p < 0.05), it demonstrated a greater 95% CI for prediction of ICP (14.62 mm Hg). nICP_CrCP presented a moderate correlation coefficient (R = 0.35; p < 0.05) and similar 95% CI to nICP_BB (9.19 mm Hg), but failed to distinguish between normal and raised ICP (AUC = 0.64; p > 0.05). nICP_PI was not related to measured ICP using any of the above statistical indicators. We also introduced a new estimator (nICP_Av) based on the average of three methods (nICP_BB, nICP_FVd, and nICP_CrCP), which overall presented improved statistical indicators (R = 0.47; p < 0.05; 95% CI = 9.17 mm Hg; AUC = 0.73; p < 0.05). nICP_PI appeared to reflect changes in ICP in time most accurately. nICP_BB was the best estimator for ICP ''as a number.'' nICP_Av demonstrated to improve the accuracy of measured ICP estimation.

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Section: Patient Populationmentioning

confidence: 99%

mentioning

confidence: 99%

Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods

Cardim

Robba

Donnelly

et al. 2016

Journal of Neurotrauma

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“…The method is based on the different acoustic properties of intracranial components (cerebral tissue, blood, CSF) such as ultrasound speed, and frequency dependent attenuation, measuring the acoustic properties of the intracranial media. A change of the content of intracranial components inside the acoustic path influences the total acoustic characteristics of the intracranial media and the monitored parameters of the ultrasonic signal as well .…”

Section: Neurophysiological Registrations Of Functional Activitymentioning

confidence: 99%

Non-invasive assessment of intracranial pressure

et al. 2015

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Monitoring of intracranial pressure (ICP) is invaluable in the management of neurosurgical and neurological critically ill patients. Invasive measurement of ventricular or parenchymal pressure is considered the gold standard for accurate measurement of ICP but is not always possible due to certain risks. Therefore, the availability of accurate methods to non-invasively estimate ICP has the potential to improve the management of these vulnerable patients. This review provides a comparative description of different methods for non-invasive ICP measurement. Current methods are based on changes associated with increased ICP, both morphological (assessed with magnetic resonance, computed tomography, ultrasound, and fundoscopy) and physiological (assessed with transcranial and ophthalmic Doppler, tympanometry, near-infrared spectroscopy, electroencephalography, visual-evoked potentials, and otoacoustic emissions assessment). At present, none of the non-invasive techniques alone seem suitable as a substitute for invasive monitoring. However, following the present analysis and considerations upon each technique, we propose a possible flowchart based on the combination of non-invasive techniques including those characterizing morphologic changes (e.g., repetitive US measurements of ONSD) and those characterizing physiological changes (e.g., continuous TCD). Such an integrated approach, which still needs to be validated in clinical practice, could aid in deciding whether to place an invasive monitor, or how to titrate therapy when invasive ICP measurement is contraindicated or unavailable.

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“…A variety of modalities has been explored for noninvasive ICP estimation (10) through measurement of related physiological variables; for instance, using ultrasound signals to measure cerebral blood flow velocity (CBFV) indices (11), skull vibrations (12), brain tissue resonance (13), or transcranial time-of-flight (14); venous ophthalmodynamometry (15); optic nerve sheath diameter assessment (16); sensing tympanic membrane displacement (17); analyzing otoacoustic emissions (18); magnetic resonance imaging to estimate incremental intracranial compliance, and thereby ICP (19); and recordings of visual evoked potentials (20). The approach described by Ragauskas et al (21) applied external pressure on the eyeball to balance the flow characteristics in the intra- and extracranial segments of the ophthalmic artery.…”

Section: Introductionmentioning

confidence: 99%

Model-Based Noninvasive Estimation of Intracranial Pressure from Cerebral Blood Flow Velocity and Arterial Pressure

et al. 2012

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Intracranial pressure (ICP) is affected in many neurological conditions. Clinical measurement of pressure on the brain currently requires placing a probe in the cerebrospinal fluid compartment, the brain tissue, or other intracranial space. This invasiveness limits the measurement to critically ill patients. As ICP is also clinically important in conditions ranging from brain tumors and hydrocephalus to concussions, noninvasive determination of ICP would be desirable. Our model-based approach to continuous estimation and tracking of ICP uses routinely obtainable time-synchronized, noninvasive (or minimally invasive) measurements of peripheral arterial blood pressure and blood flow velocity in the middle cerebral artery (MCA), both at intra-heartbeat resolution. A physiological model of cerebrovascular dynamics provides mathematical constraints that relate the measured waveforms to ICP. Our algorithm produced patient-specific ICP estimates with no calibration or training. Using 35 hours of data from 37 patients with traumatic brain injury, we generated ICP estimates on 2,665 non-overlapping 60-beat data windows. Referenced against concurrently recorded invasive parenchymal ICP that varied over 100 mmHg across all records, our estimates achieved a mean error (bias) of 1.6 mmHg and standard deviation of error (SDE) of 7.6 mmHg. For the 1,673 data windows over 22 hours in which blood flow velocity recordings were available from both the left and right MCA, averaging the resulting bilateral ICP estimates reduced the bias to 1.5 mmHg and SDE to 5.9 mmHg. This accuracy is already comparable to that of some invasive ICP measurement methods in current clinical use.

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Implementation of non-invasive brain physiological monitoring concepts

Cited by 36 publications

References 16 publications

Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods

Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods

Non-invasive assessment of intracranial pressure

Model-Based Noninvasive Estimation of Intracranial Pressure from Cerebral Blood Flow Velocity and Arterial Pressure

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