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A noninvasive estimation of cerebral perfusion pressure using critical closing pressure.
OBJECT: Cerebral blood flow is associated with cerebral perfusion pressure (CPP), which is clinically monitored through arterial blood pressure (ABP) and invasive measurements of intracranial pressure (ICP). Based on critical closing pressure (CrCP), the authors introduce a novel method for a noninvasive estimator of CPP (eCPP). METHODS: Data from 280 head-injured patients with ABP, ICP, and transcranial Doppler ultrasonography measurements were retrospectively examined. CrCP was calculated with a noninvasive version of the cerebrovascular impedance method. The eCPP was refined with a predictive regression model of CrCP-based estimation of ICP from known ICP using data from 232 patients, and validated with data from the remaining 48 patients. RESULTS: Cohort analysis showed eCPP to be correlated with measured CPP (R = 0.851, p < 0.001), with a mean ± SD difference of 4.02 ± 6.01 mm Hg, and 83.3% of the cases with an estimation error below 10 mm Hg. eCPP accurately predicted low CPP (< 70 mm Hg) with an area under the curve of 0.913 (95% CI 0.883-0.944). When each recording session of a patient was assessed individually, eCPP could predict CPP with a 95% CI of the SD for estimating CPP between multiple recording sessions of 1.89-5.01 mm Hg. CONCLUSIONS: Overall, CrCP-based eCPP was strongly correlated with invasive CPP, with sensitivity and specificity for detection of low CPP that show promise for clinical use.G. Varsos is supported by an A. G. Leventis Foundation Scholarship and a Charter Studentship from St. Edmund’s College, Cambridge. Dr. Kolias is supported by a Royal College of Surgeons of England Research Fellowship, a National Institute for Health Research (NIHR) Academic Clinical Fellowship, and a Raymond and Beverly Sackler Studentship. He also chairs the British Neurosurgical Trainee Research Collaborative, which has been supported with an educational grant from Codman. Dr. Hutchinson is supported by an NIHR Research Professorship, the NIHR Cambridge Biomedical Research Centre, and has been appointed as the Surgical Specialty Lead for Neurosurgery, Royal College of Surgeons of England Clinical Research Initiative. He is a director of Technicam, a manufacturer of cranial access devices for neuromonitoring. He has also received honoraria from Codman. J. Pickard’s research (excluding salary) is supported by the NIHR Cambridge Biomedical Research Centre and an NIHR Senior Investigator Award. ICM+ Software is licensed by Cambridge Enterprise, Cambridge, UK, and Dr. Czosnyka and Dr. Smielewski have a financial interest in a fraction of the licensing fee. Dr. Czosnyka has also served as a consultant to Codman.This is the author accepted manuscript. The final version is available from American Association of Neurological Surgeons via http://dx.doi.org/10.3171/2014.10.JNS14613
Cerebral vasospasm affects arterial critical closing pressure.
The effect of cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH) on critical closing pressure (CrCP) has not been fully delineated. Using cerebral impedance methodology, we sought to assess the behavior of CrCP during CVS. As CrCP expresses the sum of intracranial pressure (ICP) and vascular wall tension, we also explored its role in reflecting changes in vascular tone occurring in small vessels distal to spasm. This retrospective analysis was performed using recordings from 52 patients, diagnosed with CVS through transcranial Doppler measurements. Critical closing pressure was calculated noninvasively using arterial blood pressure and blood flow velocity. Outcome was assessed at both discharge and 3 months after ictus with the Glasgow Outcome Scale. The onset of CVS caused significant decreases in CrCP (P=0.025), without any observed significant changes in ICP (P=0.134). Vasospasm induced asymmetry, with CrCP ipsilateral to CVS becoming significantly lower than contralateral (P=0.025). Unfavorable outcomes were associated with a significantly lower CrCP after the onset of CVS (discharge: P=0.014; 3 months after SAH: P=0.020). Critical closing pressure is reduced in the presence of CVS in both temporal and spatial assessments. As ICP remained unchanged during CVS, reduced CrCP most probably reflects a lower wall tension in dilated small vessels distal to spasm.GVV is supported by an A.G. Leventis Foundation Scholarship, and a Charter Studentship from St Edmund’s College, Cambridge. AGK is supported by a Royal College of Surgeons of England Research Fellowship, a National Institute for Health Research (NIHR) Academic Clinical Fellowship, and a Raymond and Beverly Sackler Studentship. JD is supported by a Woolf Fisher Trust scholarship. PJH is supported by an NIHR Research Professorship, the NIHR Cambridge Biomedical Research Centre and has been appointed as the Surgical Specialty Lead for Neurosurgery, Royal College of Surgeons of England Clinical Research Initiative. JDP and MC are supported by the NIHR Cambridge Biomedical Research Centre and JDP by NIHR Senior Investigator Award. The prospective study16 on which this retrospective analysis was based, was supported by the National Institute of Health Research, Biomedical Research Centre (Neuroscience Theme). MC was supported by NIHR Cambridge Biomedical Research Centre.This is the accepted manuscript. The final published version is available from Nature Publishing at http://www.nature.com/jcbfm/journal/vaop/ncurrent/full/jcbfm2014198a.html
Simultaneous occurrence of cerebellar medulloblastoma and pituitary adenoma: A case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens