The Use of Preoperative Transcranial Doppler Variables to Predict Which Patients do Not Need a Shunt During Carotid Endarterectomy

AbstractObjectives: to analyse whether preoperative transcranial Doppler (TCD) variables can predict intraoperative shunt requirement. Design and methods: the blood-flow velocity (BFV) in the major basal cerebral arteries was measured preoperatively with TCD, in 178 patients scheduled for CEA. Carotid artery compression and CO2 reactivity tests were also performed. Intraoperative electroencephalography was used to decide whether a shunt was needed. Differences in the probability of shunt requirement between the categories of variables were assessed with crosstabs statistics. Results: preoperative TCD criteria clearly identified a subgroup of 59 patients (33%) who did not require a shunt. In general, these patients appeared to have adequate collateral flow through the anterior communicating artery. In contrast, prediction of the need for a shunt was less reliable. TCD variables could predict the need for a shunt with a probability of only 60%.Conclusions: preoperative TCD can be used to identify patients who do not require a shunt during carotid endarterectomy

Characterisation of neonatal seizures and their treatment using continuous EEG monitoring: a multicentre experience.

OBJECTIVE: The aim of this multicentre study was to describe detailed characteristics of electrographic seizures in a cohort of neonates monitored with multichannel continuous electroencephalography (cEEG) in 6 European centres. METHODS: Neonates of at least 36 weeks of gestation who required cEEG monitoring for clinical concerns were eligible, and were enrolled prospectively over 2 years from June 2013. Additional retrospective data were available from two centres for January 2011 to February 2014. Clinical data and EEGs were reviewed by expert neurophysiologists through a central server. RESULTS: Of 214 neonates who had recordings suitable for analysis, EEG seizures were confirmed in 75 (35%). The most common cause was hypoxic-ischaemic encephalopathy (44/75, 59%), followed by metabolic/genetic disorders (16/75, 21%) and stroke (10/75, 13%). The median number of seizures was 24 (IQR 9-51), and the median maximum hourly seizure burden in minutes per hour (MSB) was 21 min (IQR 11-32), with 21 (28%) having status epilepticus defined as MSB>30 min/hour. MSB developed later in neonates with a metabolic/genetic disorder. Over half (112/214, 52%) of the neonates were given at least one antiepileptic drug (AED) and both overtreatment and undertreatment was evident. When EEG monitoring was ongoing, 27 neonates (19%) with no electrographic seizures received AEDs. Fourteen neonates (19%) who did have electrographic seizures during cEEG monitoring did not receive an AED. CONCLUSIONS: Our results show that even with access to cEEG monitoring, neonatal seizures are frequent, difficult to recognise and difficult to treat. OBERSERVATION STUDY NUMBER: NCT02160171

QEEG changes during carotid clamping in carotid endarterectomy:Spectral edge frequency parameters and relative band power parameters

Intraoperative monitoring is needed to identify accurately those patients in need of a shunt during carotid endarterectomy. EEG can be used for this purpose, but there is no consensus on the variables to use. Using a database consisting of 149 EEGs recorded from patients during carotid endarterectomy under isoflurane (n = 61) or propofol (n = 88) anesthesia and who did or did not receive a shunt, the authors investigated which of 16 derivations (common reference, Cz) and 12 parameters (relative and absolute powers and spectral edge frequencies [SEFs]) singly or in combination could best distinguish between the shunt and the nonshunt groups for the two anesthesia regimens. Receiver operating characteristic curves were used to select derivation/parameter combinations for three types of trend computation: (1) values of relative powers and SEFs during clamping (C) only, (2) clamp minus preclamp (baseline) differences (C-B), and (3) C-B differences in absolute logarithmic power (Delta logP). For both anesthesia regimens, C-B computation distinguished best between the shunt and nonshunt groups. For isoflurane anesthesia, SEF parameters were the best, and for propofol anesthesia the relative power parameters. Discriminant analysis, in which additional derivation/parameter combinations were added, increased the discriminative power of the Delta logP computation but not of the C or C-B computations. For isoflurane anesthesia, SEF 90% was the best single parameter for distinguishing between patients who did and did not need a shunt and the four best derivations were F3-Cz, P4-Cz, C4-Cz, and F7-Cz. For the propofol anesthesia, the relative power (C or C-B computations) of the delta band was the best and the four best derivations were F8-Cz, T4-Cz, C4-Cz, and F4-Cz

Curved reconstructions versus three-dimensional surface rendering in the demonstration of cortical lesions in patients with extratemporal epilepsy

RATIONALE AND OBJECTIVES. TO compare the visibility and localization of extratemporal cortical lesions in extratemporal epilepsy by using curved reconstruction (CR) and three-dimensional surface rendering (3D SR) of 3D-acquired MR images and to study the degree of confidence with which localizations are made, particularly at the gyral level. METHODS. Twenty patients with extratemporal epilepsy, based on seizure symptomatology and/or scalp electroencephalographic registrations, with an extratemporal structural lesion on conventional MR imaging, were selected for this study by a neuroradiologist with extensive experience in the assessment of epilepsy patients, Transverse T2 spin-echo, coronal fluid-attenuated inversion recovery, and transverse 3D-acquired/two-dimensionally reconstructed T1 MR images were used for the selection. A second neuroradiologist (observer 1) and a radiology resident (observer 2) assessed CR and 3D SR in random order. Both observers were masked to all patient data. The subjective visibility of lesions and gyral location were scored. The interobserver agreements for lesion visibility and localization and for degree of confidence were compared for CR and 3D SR. RESULTS. For both observers, the lesion was visible in 55% of 3D SRs and 95% of CRs. The proportion with "very clearly visible" lesions on 3D SR was 19% (4/20) according to observer 1 and 30% (6/20) according to observer 2. For CR, this proportion was substantially higher: 55% for both observers. This difference was significant for observer 1 but not for observer 2, The interobserver agreement was high for both methods. Agreement on gyral localization was 28% for CR and 40% for 3D SR. The percentage of similar confidence scores for the same gyral localization and for gyral localization with a maximum difference of one gyrus between the observers did not differ significantly for CR or 3D SR. The observers were more often confident in agreed cases in CR and moderately confident in 3D SR, CONCLUSIONS. These results suggest that CRs of the brain surface are superior to 3D SR for the visualization of extratemporal cortical lesions in patients with drug-resistant extratemporal epilepsy, If lesions are seen, no significant difference was found between the two techniques for localization; however, the degree of confidence appears higher for CR at the gyral level