scholarly journals Numerical evaluation of systematic errors of a non-invasive intracranial pressure measurement

Energetika ◽  
2018 ◽  
Vol 64 (3) ◽  
Author(s):  
Edgaras Misiulis ◽  
Gediminas Skarbalius ◽  
Algis Džiugys
Keyword(s):  
Blood Flow ◽  
Intracranial Pressure ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Systematic Error ◽  
Experimental Studies ◽  
Systematic Errors ◽  
Pressure Balance ◽  
Worst Case ◽  
Non Invasive

Intracranial pressure (ICP) monitoring procedure can be applied to aid in secondary brain damage prevention. A high invasiveness of commonly used ICP measuring methods poses a risk of complications, and therefore new non-invasive methods are currently being developed. A promising non-invasive ICP measurement method is based on the existence of pressure balance state, which is driven by the unique morphological property of ophthalmic artery (OA). The value of ICP can be obtained by evaluating blood flow or artery characteristics in different OA segments, intracranial OA segment (IOA) and extracranial OA segment (EOA). In order to increase measurement accuracy, the systematic errors must be evaluated, which requires an implementation of a numerical model encompassing various physical phenomena. In this paper, a developed numerical model is presented, which was used to solve a transient fluid–structure interaction (FSI) problem of the pulsatile blood flow in a straight, physically meaningful anisotropic, hyperelastic OA, with ICP and external pressure (Pe) loads. It was found that the systematic error based on mean cross-sectional area difference between IOA and EOA segments was {–1.48, –1.37, –1.17} mmHg with ICP = {10, 20, 30} mmHg, respectively. The systematic error based on mean blood flow velocity difference between IOA and EOA segments was {–1.84, –1.76, –1.625} mmHg with ICP = {10, 20, 30} mmHg, respectively. The presented numerical model examined the worst-case scenario in terms of boundary conditions, which were immovable, while lengths of OA segments were physiologically relevant statistical means; however, the obtained systematic errors still met the clinical standards of ANSI/AAMI, where it is stated that the error should not exceed the ± 2 mmHg in the range of 0–20 mmHg of ICP. Boundary conditions and compliance affects the systematic error in both ways (reduce or increase it); this may explain the low systematic errors obtained in experimental studies by other authors.

scholarly journals Non-invasive evaluation of cerebral hemodynamic and intracranial pressure in pediatric neuroinfections

2018 ◽  
Vol 9 (4) ◽  
pp. 485-490
Author(s):  
М. А. Georgiynts ◽  
V. А. Коrsunov ◽  
О. М. Оlkhovska ◽  
К. E. Stoliarov
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Intensive Care ◽  
Intracranial Pressure ◽  
Cerebral Perfusion ◽  
Flow Index ◽  
Non Invasive ◽  
Group I ◽  
Group Ii

The study of intracranial pressure (eICP), cerebral perfusion pressure (eCPP), cerebral blood flow index (CFI), zero flow pressure (ZFP) in 49 children hospitalized in the intensive care unit with severe course of neuroinfections was carried out. The level of consciousness was determined by the Glasgow pediatric scale. Monitoring of central and peripheral hemodynamics (ECG, heart rate, systolic, diastolic and mean blood pressure, and cardiac output), pulse oximetry, capnography, hemoglobin, hematocrit, total protein, urea, creatinine, lactate, glucose and serum electrolytes was done. An ultrasound scanner was used to perform ultrasound duplex scanning of blood flow in the left and middle cerebral artery (MCA), measuring maximum, minimum and average blood flow velocities, pulsation index (PI), and resistance index (RI). Based on the formulae of Edouard et al. indicators of eCPP, ZFP, CFI, eICP were calculated. The eSCP was also determined by the formulae of Kligenchöfer et al. and Bellner et al. All patients were divided into group I with RI > 1.3 and group II with RI < 1.3. It was found that eCPP in the group I was significantly less (29.5 ± 1.3 mm Hg) than in the II group (41.6 ± 1.7 mm Hg). Despite the lack of a reliable difference in blood pressure between groups I and II, the difference in eCPP was found due to a significant difference in eICP 34.6 ± 1.4 and 27.6 ± 0.89 mm Hg in I and II groups respectively. ZFP in group I was significantly higher than in group II. The indexes of the Glasgow coma scale was significantly lower in group I and 7.8 ± 0.6 points. There were observed direct moderate correlations between systolic blood pressure, cardiac output and eSRP and CFI, presumably associated with a loss of autoregulation. CFI in the group I was lower than in the group II. Thus, non-invasive examination of cerebral flow in MCA by duplex sonography revealed that PI > 1.3 is an informative marker of intracranial hypertension and reduction of cerebral perfusion, which is common in children with neuroinfections. To determine the eSRP and CFI it is advisable to use the formula of Edouard et al. and to determine the eICP the formula of Kligenchöfer et al. The obtained data can be useful for objectifying the severity of the condition, predicting the outcomes of neuroinfections, choosing the directions of intensive care and evaluating its effectiveness.

Influence of the mode of heating on cerebral blood flow, non‐invasive intracranial pressure and thermal tolerance in humans

2021 ◽  
Vol 599 (7) ◽  
pp. 1977-1996 ◽  
Author(s):  
Travis D. Gibbons ◽  
Philip N. Ainslie ◽  
Kate N. Thomas ◽  
Luke C. Wilson ◽  
Ashley P. Akerman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Thermal Tolerance ◽  
Non Invasive

scholarly journals Numerical model development to predict the behaviour of infant/neonate crash dummy restrained inside of an incubator under deceleration

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
A. Rabiee ◽  
H. Ghasemnejad ◽  
N. Hitchins ◽  
J. Watson ◽  
J. Roberts ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Boundary Conditions ◽  
Model Development ◽  
Experimental Studies ◽  
Validation Process ◽  
British Standard ◽  
Negative Acceleration ◽  
Infant Incubator ◽  
Complex Boundary

AbstractIn this paper, advanced finite element (FE) methods are developed to investigate the effect of deceleration on the crash dummy test complied with British Standard Engineering (BS EN 1789). These techniques, which are related to material modelling, joints and contacts, offer an advanced numerical model representing an infant incubator with all complex boundary conditions and design contents. It is shown that the response of an infant incubator is a function of the ratchet straps, the tension on the belts, the belt type and the distance of the belts from the edges of the incubator, which can significantly affect the experienced acceleration, by the infant. The validation process is performed against experimental studies and various case parameters such as crash dummy mass and negative acceleration impulse are discussed in detail. The developed numerical model is capable to predict the behaviour of the crash dummy and the incubator in terms of acceleration, trajectory and kinematics by less than 8% error.

scholarly journals Non-invasive estimation of intracranial pressure by diffuse optics − a proof-of-concept study

2020 ◽  
Author(s):  
Jonas B Fischer ◽  
Ameer Ghouse ◽  
Susanna Tagliabue ◽  
Federica Maruccia ◽  
Anna Rey-Perez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Correlation Coefficient ◽  
Correlation Spectroscopy ◽  
Critical Conditions ◽  
Proof Of Concept ◽  
Icp Monitoring ◽  
Concept Study ◽  
Non Invasive

Intracranial pressure (ICP) is an important parameter to monitor in several neuropathologies. However, because current clinically accepted methods are invasive, its monitoring is limited to patients in critical conditions. On the other side, there are other less critical conditions where ICP monitoring could still be useful, thus there is a need to develop non-invasive methods. We propose a new method to estimate ICP based on the analysis of the non-invasive measurement of pulsatile, microvascular cerebral blood flow with diffuse correlation spectroscopy. This is achieved by training a recurrent neural network using only the cerebral blood flow as the input. The method is validated using a 50% split sample method using the data from a proof-of-concept study. The study involved a population of infants (n=6) with external hydrocephalus (initially diagnosed as benign enlargement of subarachnoid spaces) as well as a population of adults (n=6) suffering from traumatic brain injury. The algorithm was applied to each cohort individually to obtain a model and an ICP estimate. In both diverse cohorts, the non-invasive estimation of ICP was achieved with an accuracy less than <4 mmHg and a negligible small bias. Furthermore, we have achieved a good correlation (Pearson's correlation coefficient >0.9) and good concordance (Lin's concordance correlation coefficient >0.9) in comparison to standard clinical, invasive ICP monitoring. This preliminary work paves the way for further investigations of this tool for the non-invasive, bed-side assessment of ICP.

scholarly journals Change in Blood Flow Velocity Pulse Waveform during Plateau Waves of Intracranial Pressure

2021 ◽  
Vol 11 (8) ◽  
pp. 1000
Author(s):  
Karol Sawicki ◽  
Michał M. Placek ◽  
Tomasz Łysoń ◽  
Zenon Mariak ◽  
Robert Chrzanowski ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intracranial Pressure ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Non Invasive ◽  
Arterial Blood ◽  
Plateau Waves ◽  
Area Under Roc Curve ◽  
Preliminary Study ◽  
Better Than

A reliable method for non-invasive detection of dangerous intracranial pressure (ICP) elevations is still unavailable. In this preliminary study, we investigate quantitatively our observation that superimposing waveforms of transcranial Doppler blood flow velocity (FV) and arterial blood pressure (ABP) may help in non-invasive identification of ICP plateau waves. Recordings of FV, ABP and ICP in 160 patients with severe head injury (treated in the Neurocritical Care Unit at Addenbrookes Hospital, Cambridge, UK) were reviewed retrospectively. From that cohort, we identified 18 plateau waves registered in eight patients. A “measure of dissimilarity” (Dissimilarity/Difference Index, DI) between ABP and FV waveforms was calculated in three following steps: 1. fragmentation of ABP and FV signal according to cardiac cycle; 2. obtaining the normalised representative ABP and FV cycles; and finally; 3. assessing their difference, represented by the area between both curves. DI appeared to discriminate ICP plateau waves from baseline episodes slightly better than conventional pulsatility index did: area under ROC curve 0.92 vs. 0.90, sensitivity 0.81 vs. 0.69, accuracy 0.88 vs. 0.84, respectively. The concept of DI, if further tested and improved, might be used for non-invasive detection of ICP plateau waves.

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