Assessment of cerebral hemodynamic parameters using pulsatile versus non-pulsatile cerebral blood outflow models

Uryga, Agnieszka; Kasprowicz, Magdalena; Calviello, Leanne; Diehl, Rolf R.; Kaczmarska, Katarzyna; Czosnyka, Marek

doi:10.1007/s10877-018-0136-1

Cited by 12 publications

(11 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the article published by Uryga and colleagues in the Februari 2019 issue, the authors aimed to assess two cerebral hemodynamic indices, namely the CrCP and τ in healthy volunteers, during alterations of end-tidal carbon dioxide concentrations (etCO 2 ) [11]. These hemodynamic indices were estimated using two different models which were developed to evaluate the changes in cerebral blood volume (ΔCaBV) based on the arterial cerebral blood flow velocity measured by TCD.…”

Section: Assessment Of Cerebral Hemodynamic Variables Using Pulsatilementioning

confidence: 99%

Journal of Clinical Monitoring and Computing 2019 end of year summary: monitoring tissue oxygenation and perfusion and its autoregulation

Sahinovic

Vos

Scheeren

2020

J Clin Monit Comput

View full text Add to dashboard Cite

Tissue perfusion monitoring is increasingly being employed clinically in a non-invasive fashion. In this end-of-year summary of the Journal of Clinical Monitoring and Computing, we take a closer look at the papers published recently on this subject in the journal. Most of these papers focus on monitoring cerebral perfusion (and associated hemodynamics), using either transcranial doppler measurements or near-infrared spectroscopy. Given the importance of cerebral autoregulation in the analyses performed in most of the studies discussed here, this end-of-year summary also includes a short description of cerebral hemodynamic physiology and its autoregulation. Finally, we review articles on somatic tissue oxygenation and its possible association with outcome.

show abstract

Section: Assessment Of Cerebral Hemodynamic Variables Using Pulsatilementioning

confidence: 99%

Journal of Clinical Monitoring and Computing 2019 end of year summary: monitoring tissue oxygenation and perfusion and its autoregulation

Sahinovic

Vos

Scheeren

2020

J Clin Monit Comput

View full text Add to dashboard Cite

show abstract

“…Parameters which, by definition, depended on unknown cross-sectional areas of arteries (S a [cm 2 ]) were normalized and given an 'n' prefix (nCVR, nC a , n∆C a BV). Formulas used to calculate the cerebrovascular parameters are discussed in detail elsewhere (Varsos et al 2014, Uryga et al 2019b. Here, we restrict ourselves to a brief description of previously mentioned parameters.…”

Section: Signal Analysismentioning

confidence: 99%

“…An estimate of the amplitude of pulsatile changes in cerebral arterial blood volume (Amp (∆C a BV)) is needed to calculate C a . Currently, two mathematical models for continuous ∆C a BV assessment have been proposed (Kim et al 2009, Uryga et al 2019b. The first presumes that cerebral blood outflow has lower pulsatility than cerebral blood inflow, and therefore that cerebral blood outflow may be approximated by average cerebral arterial inflow.…”

Section: Introductionmentioning

confidence: 99%

A comparison of the time constant of the cerebral arterial bed using invasive and non-invasive arterial blood pressure measurements

et al. 2020

Self Cite

View full text Add to dashboard Cite

Objective: The time constant of the cerebral arterial bed (τ), which is an index of brain haemodynamics, can be estimated in patients using continuous monitoring of arterial blood pressure (ABP), transcranial Doppler cerebral blood flow velocity (CBFV) and intracranial pressure (ICP) if these measures are available. But, in some clinical scenarios invasive measurement of ABP is not feasible. Therefore, in this study we aimed to investigate whether invasive ABP can be replaced with non-invasive ABP, monitored using the Finapres photoplethysmograph (fABP). Approach: Forty-six recordings of ICP, ABP, fABP, and CBFV in the right and left middle cerebral arteries were performed daily for approximately 30 min in 10 head injury patients. Two modelling approaches (constant flow forward [CFF, pulsatile blood inflow and steady blood outflow] and pulsatile flow forward [PFF, where both blood inflow and outflow are pulsatile]) were applied to estimate τ using either invasive ABP (τCFF, τPFF) or non-invasive ABP (fτCFF, fτPFF). Main results: Bland–Altman analysis showed quite poor agreement between the fτ and τ methods of estimation. The fτ method produced significantly higher values than the τ method when calculated using both the CFF and PFF models (p < .001 for both). The correlation between fτCFF and τCFF was moderately high (r s = 0.63; p < .001), whereas that between fτPFF and τPFF was weaker (r s = 0.40; p = .009). Significance: Our results suggest that using non-invasive ABP for estimation of τ is inaccurate in head injury patients.

show abstract

“…Equation 1 presumes that pulsatile inflow through the basal arteries is equilibrated by non-pulsatile blood outflow through the dural sinuses, creating the continuous flow forward model (CFF). Equation 2 presumes that the inflow of arterial blood is equilibrated by pulsatile flow forward through the regulating arterioles (the pulsatile flow forward model, PFF) [9].…”

Section: Introductionmentioning

confidence: 99%

“…where s is the arbitrary time variable of integration, CBF a is cerebral blood flow, ABP is arterial blood pressure, and CVR is cerebrovascular resistance [9]. There is great clinical interest in the application of noninvasive metrics (particularly more accurate surrogate measures of PRx and PAx) during the subacute and long-term phases of TBI care, where invasive ICP monitoring is no longer present and is thus unable to influence patient management or contribute to traditional PRx and/or PAx evaluation.…”

Section: Introductionmentioning

confidence: 99%

Validation of non-invasive cerebrovascular pressure reactivity and pulse amplitude reactivity indices in traumatic brain injury

et al. 2019

Self Cite

View full text Add to dashboard Cite

Background Two transcranial Doppler (TCD) estimators of cerebral arterial blood volume (CaBV) coexist: continuous outflow of arterial blood outside the cranium through a low-pulsatile venous system (continuous flow forward, CFF) and pulsatile outflow through regulating arterioles (pulsatile flow forward, PFF). We calculated non-invasive equivalents of the pressure reactivity index (PRx) and the pulse amplitude index PAx with slow waves of mean CaBV and its pulse amplitude. Methods About 273 individual TBI patients were retrospectively reviewed. PRx is the correlation coefficient between 30 samples of 10-second averages of ICP and mean ABP. PAx is the correlation coefficient between 30 samples of 10-second averages of the amplitude of ICP (AMP, derived from Fourier analysis of the raw full waveform ICP tracing) and mean ABP. nPRx is calculated with CaBV instead of ICP and nPAx with the pulse amplitude of CaBV instead of AMP (calculated using both the CFF and PFF models). All reactivity indices were additionally compared with Glasgow Outcome Score (GOS) to verify potential outcome-predictive strength. Results When correlated, slow waves of ICP demonstrated good coherence between slow waves in CaBV (>0.75); slow waves of AMP showed good coherence with slow waves of the pulse amplitude of CaBV (>0.67) in both the CFF and PFF models. nPRx was moderately correlated with PRx (R = 0.42 for CFF and R = 0.38 for PFF; p < 0.0001). nPAx correlated with PAx with slightly better strength (R = 0.56 for CFF and R = 0.41 for PFF; p < 0.0001). nPAx_CFF showed the strongest association with outcomes. Conclusions Non-invasive estimators (nPRx and nPAx) are associated with their invasive counterparts and can provide meaningful associations with outcome after TBI. The CFF model is slightly superior to the PFF model.

show abstract

Assessment of cerebral hemodynamic parameters using pulsatile versus non-pulsatile cerebral blood outflow models

Abstract: Our results suggest that the pulsatile flow forward model better reflects changes in CrCP and in τ induced by controlled alterations in EtCO.

Cited by 12 publications

References 31 publications

Journal of Clinical Monitoring and Computing 2019 end of year summary: monitoring tissue oxygenation and perfusion and its autoregulation

Journal of Clinical Monitoring and Computing 2019 end of year summary: monitoring tissue oxygenation and perfusion and its autoregulation

A comparison of the time constant of the cerebral arterial bed using invasive and non-invasive arterial blood pressure measurements

Validation of non-invasive cerebrovascular pressure reactivity and pulse amplitude reactivity indices in traumatic brain injury

Contact Info

Product

Resources

About