Cerebral haemodynamics during experimental intracranial hypertension

Donnelly, Joseph E.; Czosnyka, Marek; Harland, Spencer P.; Varsos, Georgios V.; Cardim, Danilo; Robba, Chiara; Liu, Xiuyun; Ainslie, Philip N.; Smielewski, Peter

doi:10.1177/0271678x16639060

Cited by 27 publications

(30 citation statements)

References 45 publications

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“…For example, one animal experiment revealed a 2‐way correlation between the PI and CVR under different conditions . Moreover, we had little knowledge about the effect of craniectomy (rather than a craniectomy‐induced ICP reduction) or cranioplasty on the MCA PI, and the surgery (craniectomy or cranioplasty) may alter cerebral hemodynamics . Additionally, we found no significant correlation between the MCA PI and the CPP ( P > .05), and the MCA PI poorly predicted the CPP (AUC <0.75).…”

Section: Discussionmentioning

confidence: 75%

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Use of a Doppler‐Based Pulsatility Index to Evaluate Cerebral Hemodynamics in Neurocritical Patients After Hemicraniectomy

Gao

et al. 2019

J of Ultrasound Medicine

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ObjectivesAs a noninvasive method for evaluation of cerebral hemodynamics, the correct interpretation of transcranial Doppler or transcranial imaging (TCI) data remains a major challenge. We explored how to interpret the pulsatility index (PI) derived via TCI during evaluations of cerebral hemodynamics in posthemicraniectomy patients.MethodsWe included patients who underwent invasive arterial pressure and intracranial pressure (ICP) monitoring and simultaneous TCI examinations after hemicraniectomy. We classified the PI of the middle cerebral artery (MCA) into ipsilateral (craniectomy side) and contralateral (opposite side) and analyzed both data sets. The statistical analysis was performed by the Bland‐Altman approach, by calculating intraclass correlation coefficients and Spearman correlations, and by drawing receiver operating characteristic curves. Pulsatility index probability charts were created for ICPs exceeding 20, 25, and 30 mm Hg and cerebral perfusion pressures (CPPs) lower than 70, 60, and 50 mm Hg; we thus explored defined ICP and CPP values.ResultsThe ipsilateral and contralateral MCA PI data differed. Only the ipsilateral MCA PI showed a weak correlation with ICP (r = 0.378; P < .001). The receiver operating characteristic curve analysis revealed limited diagnostic utility of bilateral MCA PIs for ICP and CPP assessments. An extremely elevated MCA PI indicated that patients were at high risk of a dangerous ICP elevation or CPP reduction. However, MCA PI values within the normal range did not effectively rule out an ICP of 20 mm Hg or higher but effectively eliminated a CPP lower than 50 mm Hg.ConclusionsIn posthemicraniectomy patients, the Doppler‐based MCA PI value was ineffectively for quantitative ICP and CPP evaluations but a useful index for assessment of cerebral hemodynamics in terms of the probability of an ICP elevation or a CPP reduction.

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Section: Discussionmentioning

confidence: 75%

“…The MCA PI was very commonly misinterpreted as an alternative index of cerebrovascular resistance (CVR) in previous studies . By reference to the ICP, CVR increased, followed by an MCA PI increase, as the ICP varied.…”

Section: Discussionmentioning

confidence: 99%

Use of a Doppler‐Based Pulsatility Index to Evaluate Cerebral Hemodynamics in Neurocritical Patients After Hemicraniectomy

Gao

et al. 2019

J of Ultrasound Medicine

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“…Regardless of the cause, CFS leaks or depletion leads to intracranial hypotension (IH). Any change in intracranial pressure (ICP) may influence cerebral blood flow (CBF) [3][4][5]. Although there is plenty of data regarding CBF during intracranial hypertension, surprisingly little is known about CBF characteristics during low intracranial pressure.…”

Section: Introductionmentioning

confidence: 99%

Cerebral Blood Flow in Low Intracranial Pressure Headaches—What Is Known?

Nowaczewska

Kaźmierczak

2019

Brain Sciences

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Headaches attributed to low cerebrospinal fluid (CSF) pressure are described as orthostatic headaches caused by spontaneous or secondary low CSF pressure or CSF leakages. Regardless of the cause, CFS leaks may lead to intracranial hypotension (IH) and influence cerebral blood flow (CBF). When CSF volume decreases, a compensative increase in intracranial blood volume and cerebral vasodilatation occurs. Sinking of the brain and traction on pain-sensitive structures are thought to be the causes of orthostatic headaches. Although there are many studies concerning CBF during intracranial hypertension, little is known about CBF characteristics during low intracranial pressure. The aim of this review is to examine the relationship between CBF, CSF, and intracranial pressure in headaches assigned to low CSF pressure.

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“…RAP values near zero, or negative, can indicate both preserved and impaired cerebral compensatory reserve, depending on which aspect of the inverse parabolic relationship is being observed [9, 27]. Plots of RAP vs ICP or cerebral perfusion pressure (CPP) demonstrate an inverse parabolic relationship, with moderate/severe impairment of compensatory reserve indicated by positive values of RAP.…”

Section: Introductionmentioning

confidence: 99%

Impaired cerebral compensatory reserve is associated with admission imaging characteristics of diffuse insult in traumatic brain injury

et al. 2018

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BackgroundContinuous assessment of cerebral compensatory reserve is possible using the moving correlation between pulse amplitude of intra-cranial pressure (AMP) and intra-cranial pressure (ICP), called RAP. Little is known about the behavior and associations of this index in adult traumatic brain injury (TBI). The goal of this study is to evaluate the association between admission cerebral imaging findings and RAP over the course of the acute intensive care unit stay.MethodsWe retrospectively reviewed 358 adult TBI patients admitted to the Addenbrooke’s Hospital, University of Cambridge, from March 2005 to December 2016. Only non-craniectomy patients were studied. Using archived high frequency physiologic signals, RAP was derived and analyzed over the first 48 h and first 10 days of recording in each patient, using grand mean, percentage of time above various thresholds, and integrated area under the curve (AUC) of RAP over time. Associations between these values and admission computed tomography (CT) injury characteristics were evaluated.ResultsThe integrated AUC, based on various thresholds of RAP, was statistically associated with admission CT markers of diffuse TBI and cerebral edema. Admission CT findings of cortical gyral effacement, lateral ventricle compression, diffuse cortical subarachnoid hemorrhage (SAH), thickness of cortical SAH, presence of bilateral contusions, and subcortical diffuse axonal injury (DAI) were all associated with AUC of RAP over time. Joncheere-Terpstra testing indicated a statistically significant increase in mean RAP AUC across ordinal categories of the abovementioned associated CT findings.ConclusionsRAP is associated with cerebral CT injury patterns of diffuse injury and edema, providing some confirmation of its potential measurement of cerebral compensatory reserve in TBI.Electronic supplementary materialThe online version of this article (10.1007/s00701-018-3681-y) contains supplementary material, which is available to authorized users.

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Cerebral haemodynamics during experimental intracranial hypertension

Cited by 27 publications

References 45 publications

Use of a Doppler‐Based Pulsatility Index to Evaluate Cerebral Hemodynamics in Neurocritical Patients After Hemicraniectomy

Use of a Doppler‐Based Pulsatility Index to Evaluate Cerebral Hemodynamics in Neurocritical Patients After Hemicraniectomy

Cerebral Blood Flow in Low Intracranial Pressure Headaches—What Is Known?

Impaired cerebral compensatory reserve is associated with admission imaging characteristics of diffuse insult in traumatic brain injury

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