Intraoperative seizures during neuro-oncological supratentorial surgery: the role of prophylaxis with levetiracetam and intraoperative monitoring in a consecutive series of 353 patients.

BACKGROUND: The aim of this paper was to understand the role of prophylaxis with levetiracetam at skin incision in preventing convulsive intraoperative seizures (IOS) during neurosurgical procedures with and without intraoperative neuromonitoring (IONM). METHODS: Authors retrospectively reviewed the Institutional database for cases of supratentorial brain tumors undergoing surgical resection performed from January 2021 to October 2022. Patients were operated on both under general anesthesia and awake, using motor-evoked potentials (MEP) and direct cortical stimulation for cortical mapping. 1000 mg ev of Levetiracetam before skin incision in case of a history of seizures was administrated. We excluded all infratentorial cases. RESULTS: Three hundred fisty three consecutive cases were retrieved. IOS occurred in 22 patients (6.2%). Prophylaxis with Levetiracetam was administered in 149 patients, and IOS occurred in 16 cases (10.7%) in this group of patients. The IOS rate in the case of no Levetiracetam prophylaxis administration (3.5%) was significantly lower (P<0.001, OR=3.38 [1.35-8.45], RR=3.12 [1.32-7.41]). The Penfield technique stimulation evoked seven of all 22 IOS reported (31.8%) (P=0.006, RR 5.4 [1.44 -20.58], OR 21 [2.3-183.9]), and the train-of-five technique stimulation caused two of all registered IOS (8.7%) (P=0.2, RR 2.3 [0.99-5.67], OR 6.5 [0.55-76.17]). Transcranial MEPs evoked no IOS. CONCLUSIONS: Under levetiracetam prophylaxis, the IOS rate was not significantly lower than in the group of patients without Levetiracetam prophylaxis, regardless of the histology of the tumor and IONM. Neither the transcranial stimulation (MEP) nor train-of-five technique stimulation increases the risk of convulsive IOS, as Penfield technique stimulation does.

Is the Patient State Index a reliable parameter as guide to anaesthesiology in cranial neurosurgery? A first intraoperative study and a literature review.

BACKGROUND: Patient State Index (PSI) and Suppression Ratio (SR) are two indices calculated by quantitative analysis of EEG used to estimate the depth of anaesthesia but their validation in neurosurgery must be done. Our aim was to investigate the congruity PSI and SR with raw EEG monitoring in neurosurgery. METHODS: We included 34 patients undergoing elective cranial neurosurgery. Each patient was monitored by a SedLine device (PSI and SR) and by raw EEG. To appraise the agreement between PSI, SR and EEG Suppr%, Bland-Altman analysis was used. We also correlated the PSI and SR recorded at different times during surgery to the degree of suppression of the raw EEG data by Spearman's rank correlation coefficient. For a comparison with previous data we made an international literature review according to PRISMA protocol. RESULTS: At all recording times, we found that there is a strong agreement between PSI and raw EEG. We also found a significant correlation for both PSI and SR with the EEG suppression percentage (p < 0.05), but with a broad dispersion of the individual values within the confidence interval. CONCLUSION: The Masimo SedLine processed EEG monitoring system can be used as a guide in the anaesthetic management of patients during elective cranial neurosurgery, but the anaesthesiologist must be aware that previous correlations between PSI and SR with the suppression percentage may not always be valid in all individual patients. The use of an extended visual raw EEG evaluated by an expert electroencephalographer might help to provide better guidance.

Intraoperative Mapping of the Sensory Root of the Trigeminal Nerve in Patients with Pontocerebellar Angle Pathology.

OBJECTIVE: The aim of the present study was to determine the position of the 3 sensory branches of the trigeminal nerve in the preganglionic tract using intraoperative neurophysiological mapping. METHODS: We included consecutive adult patients who underwent neurosurgical treatment of cerebellopontine angle lesions. The trigeminal nerve was antidromically stimulated at 3 sites along its circumference with different stimulus intensities at a distance of ≤1 cm from the brainstem. The sensory nerve action potentials (SNAPs) were recorded from each main trigeminal branch (V1 [ophthalmic branch], V2 [maxillary branch], and V3 [mandibular branch]). RESULTS: We analyzed 13 patients. The stimulation points at which we obtained the greatest number of congruous and exclusive SNAPs (SNAPs only on the stimulated branch) was the stimulation point for V3 (20.7%). The stimulation intensity at which we obtained the highest number of congruent and exclusive SNAPs with the stimulated branch was 0.5 mA. CONCLUSIONS: Using our recording conditions, trigeminal stimulation is a reliable technique for mapping the V3 and V1 branches using an intensity not exceeding 0.5. However, reliable identification of the fibers of V2 is more difficult. Stimulation of the trigeminal nerve can be a reliable technique to identify the V3 and V1 branches if rhizotomy of these branches is necessary.

Feasibility of Intraoperative Visual Evoked Potential Monitoring by Cortical Strip Electrodes in Patients During Brain Surgery: A Preliminary Study.

OBJECTIVE: The role of visual evoked potentials (VEPs) monitoring during neurosurgical procedure in patient remains unclear. The purpose of our study was to determine the feasibility of intraoperative VEP recording using a strip cortical electrode during surgical resection of intracranial lesions. METHODS: In this prospective, monocentric, observational study, we enrolled consecutive patients undergoing neurosurgical procedure for intracranial lesions. After dural opening, a cortical strip was positioned on the lateral occipital surface. Flash VEPs were continuously recorded using both subdermal corkscrew electrodes and strip electrodes. An electroretinogram was also recorded to guarantee delivery of adequate flash stimuli to the retina. RESULTS: We included 10 patients affected by different intracranial lesions. Flash VEPs were recorded using subdermal corkscrew electrodes in all patients except 1 in whom they were never identified during the recording. Flash VEPs were recorded using strip electrodes in all patients and showed a polyphasic morphology with a significantly larger amplitude compared with that of flash VEPs measured using subdermal corkscrew electrodes. No patient reported worsened postoperative vision and a >50% decrease in the VEPs amplitude was never registered. CONCLUSIONS: We have reported for the first time in the literature that VEP monitoring during a neurosurgical procedure is feasible via a cortical strip located on the occipital surface. The technique demonstrated greater stability and a larger amplitude compared with recordings with scalp electrodes, facilitating identification of any changes. Studies with more patients are needed to assess the clinical reliability of the technique.

Do changes in SSEP amplitude over time predict the outcome of comatose survivors of cardiac arrest?

AIM: To assess if the amplitude of the N20 wave (N20Amp) of somatosensory evoked potentials (SSEPs) changes between 12-24 h and 72 h from the return of spontaneous circulation (ROSC) after cardiac arrest and if an N20Amp decrease predicts poor neurological outcome (CPC 3-5) at six months. SETTING: Retrospective analysis of the ProNeCA multicentre prognostication study dataset. (NCT03849911). METHODS: In adult comatose cardiac arrest survivors whose SSEPs were recorded at both 12-24 h and 72 h after ROSC, we measured the median N20Amp at each timepoint and the individual change in N20Amp across the two timepoints. We identified their cutoffs for predicting poor outcome with 0% false positive rate (FPR) and compared their sensitivities. RESULTS: We included 236 patients. The median [IQR] N20Amp increased from 1.90 [0.78-4.22] µV to 2.86 [1.52-5.10] µV between 12-24 h and 72 h (p = 0.0019). The N20Amp cutoff for 0% FPR increased from 0.6 µV at 12-24 h to 1.23 µV at 72 h, and its sensitivity increased from 56[48-64]% to 71[63-77]%. Between 12-24 h and 72 h, an N20Amp decrease > 53% predicted poor outcome with 0[0-5]% FPR and 26[19-35]% sensitivity. Its combination with an N20Amp < 1.23 µV at 72 h increased sensitivity by 1% to 72[64-79]%. CONCLUSION: In comatose cardiac arrest survivors, the median N20Amp and its cutoff for predicting poor neurological outcome increase between 12-24 and 72 h after ROSC. An N20Amp decrease greater than 53% between these two timepoints predicts poor outcome with 0% FPR, confirming the unfavourable prognostic signal of a low N20Amp at 72 h.

Surgical Resolution of Trigeminal Neuralgia Complicating Vestibular Schwannoma Removal.

This work illustrates the case of surgical treatment of trigeminal neuralgia (TN), as a tardive complication after vestibular schwannoma (VS) removal (Koos III, Figure 1), in a female patient. After VS surgery, the postoperative computed tomography scan did not show any significant complication, although a thin blood clot was present in the surgical bed (Figure 2). However, 3 months later, our patient developed a TN involving the territories V2-V3. Medical therapies were ineffective. Several magnetic resonance imaging scans confirmed a left dislocation of the brainstem (Figures 3 and 4), probably due to the previous clot retraction. The anatomic-functional preservation of the left Tn was documented using the laser-evoked potentials. Fifteen months after surgery, our patient underwent a second operation aimed at exploring the Tn territory, with the use of the intraoperative monitoring and mapping the fifth and seventh cranial nerves. A neurovascular conflict, caused by scar tissue involving the superior cerebellar artery, a small vein, and the Tn, was detected and surgically solved (Figure 5). Postoperative analgesic treatment was progressively reduced and suspended. The case is illustrated and explained in the Video 1. The paucity of cases reported in the literature lead us to think that TN as complication of VS removal is underestimated because it may be responsive to medical treatment. Laser-evoked potentials may be useful to study the integrity of the Tn, ensuring that no anatomic damage has been done during surgery. On the basis of our experience, surgery can be an effective treatment option when TN is not responsive to medical therapy and the anatomic-functional integrity of the Tn has been preserved.

SSEP amplitude accurately predicts both good and poor neurological outcome early after cardiac arrest; a post-hoc analysis of the ProNeCA multicentre study.

AIM: To assess if, in comatose resuscitated patients, the amplitude of the N20 wave (N20amp) of somatosensory evoked potentials (SSEP) can predict 6-months neurological outcome. SETTING: Multicentre study in 13 Italian intensive care units. METHODS: The N20amp in microvolts (µV) was measured at 12 h, 24 h, and 72 h from cardiac arrest, along with pupillary reflex (PLR) and a 30-min EEG classified according to the ACNS terminology. Sensitivity and false positive rate (FPR) of N20amp alone or in combination were calculated. RESULTS: 403 patients (age 69[58-68] years) were included. At 12 h, an N20amp >3 µV predicted good neurological outcome (Cerebral Performance Categories [CPC] 1-2) with 61[50-72]% sensitivity and 11[6-18]% FPR. Combining it with a benign (continuous or nearly continuous) EEG increased sensitivity to 91[82-96]%. For poor outcome (CPC 3-5), an N20Amp ≤0.38 µV, ≤0.73 µV and ≤1.01 µV at 12 h, 24 h, and 72 h, respectively, had 0% FPR with sensitivity ranging from 61[51-69]% and 82[76-88]%. Sensitivity was higher than that of a bilaterally absent N20 at all time points. At 12 h and 24 h, a highly malignant (suppression or burst-suppression) EEG and bilaterally absent PLR achieved 0% FPR only when combined with SSEP. A combination of all three predictors yielded a 0[0-4]% FPR, with maximum sensitivity of 44[36-53]%. CONCLUSION: At 12 h from arrest, a high N20Amp predicts good outcome with high sensitivity, especially when combined with benign EEG. At 12 h and 24 h from arrest a low-voltage N20amp has a high sensitivity and is more specific than EEG or PLR for predicting poor outcome.

Are neurophysiologic tests reliable, ultra-early prognostic indices after cardiac arrest?

OBJECTIVES: Determining early and reliable prognosis in comatose subjects after cardiac arrest is a central component of post-cardiac arrest care both for developing realistic prognostic expectations for families, and for better determining which resources are mobilized or withheld for individual patients. The aim of the study was to evaluate the prognostic accuracy of EEG and SEP patterns during the very early period (within the first 6 h) after cardiac arrest. METHODS: We retrospectively analysed comatose patients after CA, either inside or outside the hospital, in which prognostic evaluation was made during the first 6 h from CA. Prognostic evaluation comprised clinical evaluation (GCS and pupillary light reflex) and neurophysiological (electroencephalography (EEG) and somatosensory evoked potentials (SEP)) studies. Prognosis was evaluated with regards to likelihood of recovery of consciousness and also likelihood of failure to regain consciousness. RESULTS: Forty-one comatose patients after cardiac arrest were included. All patients with continuous and nearly continuous EEG recovered consciousness. Isoelectric EEG was always associated with poor outcome. Burst-suppression, suppression and discontinuous patterns were usually associated with poor outcome although some consciousness recovery was observed. Bilaterally absent SEP responses were always associated with poor outcome. Continuous and nearly continuous EEG patterns were never associated with bilaterally absent SEP. CONCLUSIONS: During the very early period following cardiac arrest (first 6 h), EEG and SEP maintain their high predictive value to predict respectively recovery and failure of recovery of consciousness. A very early EEG exam allows identification of patients with very high probability of a good outcome, allowing rapid use of the most appropriate therapeutic procedures.

Does a combination of ≥2 abnormal tests vs. the ERC-ESICM stepwise algorithm improve prediction of poor neurological outcome after cardiac arrest? A post-hoc analysis of the ProNeCA multicentre study.

BACKGROUND: Bilaterally absent pupillary light reflexes (PLR) or N20 waves of short-latency evoked potentials (SSEPs) are recommended by the 2015 ERC-ESICM guidelines as robust, first-line predictors of poor neurological outcome after cardiac arrest. However, recent evidence shows that the false positive rates (FPRs) of these tests may be higher than previously reported. We investigated if testing accuracy is improved when combining PLR/SSEPs with malignant electroencephalogram (EEG), oedema on brain computed tomography (CT), or early status myoclonus (SM). METHODS: Post-hoc analysis of ProNeCA multicentre prognostication study. We compared the prognostic accuracy of the ERC-ESICM prognostication strategy vs. that of a new strategy combining ≥2 abnormal results from any of PLR, SSEPs, EEG, CT and SM. We also investigated if using alternative classifications for abnormal SSEPs (absent-pathological vs. bilaterally-absent N20) or malignant EEG (ACNS-defined suppression or burst-suppression vs. unreactive burst-suppression or status epilepticus) improved test sensitivity. RESULTS: We assessed 210 adult comatose resuscitated patients of whom 164 (78%) had poor neurological outcome (CPC 3-5) at six months. FPRs and sensitivities of the ≥2 abnormal test strategy vs. the ERC-ESICM algorithm were 0[0-8]% vs. 7 [1-18]% and 49[41-57]% vs. 63[56-71]%, respectively (p < .0001). Using alternative SSEP/EEG definitions increased the number of patients with ≥2 concordant test results and the sensitivity of both strategies (67[59-74]% and 54[46-61]% respectively), with no loss of specificity. CONCLUSIONS: In comatose resuscitated patients, a prognostication strategy combining ≥2 among PLR, SSEPs, EEG, CT and SM was more specific than the 2015 ERC-ESICM prognostication algorithm for predicting 6-month poor neurological outcome.

A multimodal diagnostic approach for lateralised rhythmic delta activity in the ictal-interictal continuum.

The ictal-interictal continuum represents a diagnostic challenge even for expert neurrophysiologists, often requiring an additional multimodal diagnostic workup to understand its clinical significance. Lateralised rhythmic delta activity (LRDA) is an ictal-interictal continuum pattern that has only recently been investigated and recognised as potentially ictogenic or sometimes even ictal. We describe a patient who presented with acute-onset aphasia, initially suspected of having a stroke; advanced brain imaging with CT-perfusion showed features suggesting regional left temporo-parietal hyperperfusion and an EEG revealed LRDA with fluctuations and intermixed sharp waves in the same areas. Treatment with lacosamide caused both clinical and EEG improvement after a few hours, supporting the hypothesis that the EEG pattern represented an ictal/interictal phenomenon. In the literature, a correlation between metabolic/perfusion imaging and ictal-interictal continuum patterns is described regarding lateralised periodic discharges but less studied for LRDA. In this case, we adopted a multimodal approach, integrating advanced imaging, EEG, clinical features, and response to therapy, to consider the overall clinical presentation as focal NCSE.

Neurophysiology for predicting good and poor neurological outcome at 12 and 72 h after cardiac arrest: The ProNeCA multicentre prospective study.

AIMS: To assess the accuracy of electroencephalogram (EEG) and somatosensory evoked potentials (SEPs) recorded at 12 and 72 h from resuscitation for predicting six-months neurological outcome in patients who are comatose after cardiac arrest. METHODS: Prospective multicentre prognostication study. EEG was classified according to the American Clinical Neurophysiology Society terminology. SEPs were graded according to the presence and amplitude of their cortical responses. Neurological outcome was defined as good (cerebral performance categories [CPC] 1-3) vs. poor (CPC 4-5). None of the patients underwent withdrawal of life-sustaining treatment. RESULTS: A total of 351 patients were included, of whom 134 (38%) had good neurological outcome. At 12 h, a continuous, nearly continuous and low-voltage EEG pattern predicted good neurological outcome with 71[61-80]% sensitivity, while an isoelectric EEG and a bilaterally absent/absent-pathological amplitude (AA/AP) cortical SEP pattern predicted poor neurological outcome with 14[8-21]% and 59[50-68]% sensitivity, respectively. Specificity was 100[97-100]% for all predictors. At 72 h, both an isoelectric, suppression or burst-suppression pattern on EEG and an AA/AP SEP pattern predicted poor outcome with 100[97-100]% specificity. Their sensitivities were 63[55-70]% and 66[58-74]%, respectively. When EEG and SEPs were combined, sensitivity for poor outcome prediction increased to 79%. CONCLUSIONS: In comatose resuscitated patients, EEG and SEPs predicted good and poor neurological outcome respectively, with 100% specificity as early as 12 h after cardiac arrest. At 72 h after arrest, unfavourable EEG and SEP patterns predicted poor neurological outcome with 100% specificity and high sensitivity, which further increased after their combination.

Neurophysiological and neuroradiological test for early poor outcome (Cerebral Performance Categories 3-5) prediction after cardiac arrest: Prospective multicentre prognostication data.

The data presented here are related to our research article entitled "Neurophysiology and neuroimaging accurately predict poor neurological outcome within 24 hours after cardiac arrest: a prospective multicentre prognostication study (ProNeCA)" [1]. We report a secondary analysis on the ability of somatosensory evoked potentials (SEPs), brain computed tomography (CT) and electroencephalography (EEG) to predict poor neurological outcome at 6 months in 346 patients who were comatose after cardiac arrest. Differently from the related research article, here we included cerebral performance category (CPC) 3 among poor outcomes, so that the outcomes are dichotomised as CPC 1-2 (absent to mild neurological disability: good outcome) vs. CPC 3-5 (severe neurological disability, persistent vegetative state, or death: poor outcome). The accuracy of the index tests was recalculated accordingly. A bilaterally absent/absent-pathological amplitude (AA/AP) N20 SEPs wave, a Grey Matter/White Matter (GM/WM) ratio <1.21 on brain CT and an isoelectric or burst suppression EEG predicted poor outcome with 49.6%, 42.2% and 29.8% sensitivity, respectively, and 100% specificity. The distribution of positive results of the three predictors did not overlap completely in the population of patients with poor outcome, so that when combining them the overall sensitivity raised to 61.2%.

Neurophysiology and neuroimaging accurately predict poor neurological outcome within 24 hours after cardiac arrest: The ProNeCA prospective multicentre prognostication study.

AIMS: To investigate the ability of 30-min electroencephalogram (EEG), short-latency somatosensory evoked potentials (SEPs) and brain computed tomography (CT) to predict poor neurological outcome (persistent vegetative state or death) at 6 months in comatose survivors of cardiac arrest within 24 h from the event. METHODS: Prospective multicentre prognostication study in seven hospitals. SEPs were graded according to the presence and amplitude of their cortical responses, EEG patterns were classified according to the American Clinical Neurophysiology Society terminology and brain oedema on brain CT was measured as grey/white matter (GM/WM) density ratio. Sensitivity for poor outcome prediction at 100% specificity was calculated for the three tests individually and in combination. None of the patients underwent withdrawal of life-sustaining treatments before the index event occurred. RESULTS: A total of 346/396 patients were included in the analysis. At 6 months, 223(64%) had poor neurological outcome; of these, 68 were alive in PVS. Bilaterally absent/absent-pathological amplitude cortical SEP patterns, a GM/WM ratio<1.21 on brain CT and isoelectric/burst-suppression EEG patterns predicted poor outcome with 100% specificity and sensitivities of 57.4%, 48.8% and 34.5%, respectively. At least one of these unfavourable patterns was present in 166/223 patients (74.4% sensitivity). Two unfavourable patterns were simultaneously present in 111/223 patients (49.7% sensitivity), and three patterns in 38/223 patients (17% sensitivity). CONCLUSIONS: In comatose resuscitated patients, a multimodal approach based on results of SEPs, EEG and brain CT accurately predicts poor neurological outcome at 6 months within the first 24 h after cardiac arrest.

Early-SEPs' amplitude reduction is reliable for poor-outcome prediction after cardiac arrest?

OBJECTIVE: The bilateral absence of cortical Somatosensory Evoked Potentials (SEPs), after cardiac arrest (CA), is a high reliable predictor of poor outcome but it is present in no more than 40% of patients. An amplitude reduction of cortical SEPs was found in about 30% of subjects, but few papers analysed its prognostic significance. The aim of our study is to identify a value of SEP amplitude reduction below which all the CA patients had poor outcome and the relationship between SEP and Electroencephalogram (EEG) patterns. MATERIAL AND METHODS: We analysed comatose patients in whom SEPs and EEG were recorded at 6-12 hours after CA. We evaluated the sensitivity at specificity of 100% of SEP amplitude in predicting the non-recovery of consciousness by plotting Receiver Operating Characteristic (ROC) curves. We also analysed the relationship between SEP amplitude and EEG patterns. Outcome was evaluated at 6 months by Glasgow Outcome Scale. RESULTS: We analysed 119 subjects. According to the ROC analysis (area under the curve = 0.95/CI 0.91-0.99), all patients with a cortical SEP amplitude <0.65 µV did not recover consciousness (GOS 1-2), with a sensitivity of 71.8%. Severe EEG abnormalities (suppression and burst-suppression patterns) were also observed in all these patients. CONCLUSION: Not only the absence but also a bilateral amplitude reduction of cortical SEPs (<0.65 µV) is associated with ominous prognosis (death or non-recovery of consciousness) with a very high predictive value. However, we emphasize that great caution should be applied before adopting amplitude reduction as a criterion for the poor prognosis of CA patients.

Amplitude Instability of Somatosensory Evoked Potentials as an Indicator of Delayed Cerebral Ischemia in a Case of Subarachnoid Hemorrhage.

We describe a 55-year-old male patient with a subarachnoid hemorrhage (SAH) as a result of left middle cerebral artery (MCA) aneurysm rupture, who underwent continuous electroencephalogram (EEG) and somatosensory evoked potential (cEEG-SEP) monitoring that showed an unusual SEP trend pattern. EEG was continuously recorded, and SEPs following stimulation of median nerves were recorded every 50 minutes, with the amplitude and latency of the cortical components automatically trended. An increase in intracranial pressure required a left decompressive craniectomy. cEEG-SEP monitoring was started on day 7, which showed a prolonged (24 hours) instability of SEPs in the left hemisphere. During this phase, left MCA vasospasm was demonstrated by transcranial Doppler (TCD), and computed tomography perfusion (CTP) showed a temporo-parieto-occipital ischemic penumbra. Following intravascular treatment, hypoperfusion and the amplitude of cortical SEPs improved. In our case, a prolonged phase of SEP amplitude instability during vasospasm in SAH correlated with a phase of ischemic penumbra, as demonstrated by CTP. In SAH, SEP instability during continuous monitoring is a pattern of alert that can allow treatments capable of avoiding irreversible neurological deterioration.

Data on multimodal approach for early poor outcome (Cerebral Performance Categories 3-5) prediction after cardiac arrest.

The data presented in this article are related to our research article entitled 'Neurophysiological and neuroradiological multimodal approach for early poor outcome prediction after cardiac arrest' (Scarpino et al., 2018) [1]. We reported two additional analyses, including results gathered from somatosensory evoked potentials(SEPs), brain computed tomography(CT) and electroencephalography(EEG) performed on 183 subjects within the first 24 h after cardiac arrest(CA). In the first analysis, we considered the Cerebral Performance Categories(CPC) 3, 4 and 5a,b (severe disability, unresponsive wakefulness state, neurological death and non-neurological death, respectively) as poor outcomes. In the second analysis, patients that died from non-neurological causes (CPC 5b) were excluded from the analysis. Concerning the first analysis, bilateral absent/absent-pathologic(AA/AP) cortical SEPs predicted poor outcome with a sensitivity of 49.3%. A Grey Matter/White Matter(GM/WM) ratio <1.21 predicted poor outcome with a sensitivity of 41.7%. Isoelectric/burst-suppression EEG patterns predicted poor outcome with a sensitivity of 33.5%. If at least one of these poor prognostic patterns was present, the sensitivity for an ominous outcome increased to 60.9%. Concerning the second analysis, AA/AP cortical SEPs predicted poor outcome with a sensitivity of 52.5%. GM/WM ratio <1.21 predicted poor outcome with a sensitivity of 50.4%. Isoelectric/burst-suppression EEG patterns predicted poor outcome with a sensitivity of 39.8%.

Neurophysiological and neuroradiological multimodal approach for early poor outcome prediction after cardiac arrest.

INTRODUCTION: Prognosticating outcome after cardiac arrest(CA) requires a multimodal approach. However, evidence regarding combinations of methods is limited. We evaluated whether the combination of electroencephalography(EEG), somatosensory evoked potentials(SEPs) and brain computed tomography(CT) could predict poor outcome. METHODS: We screened our database regarding patients successfully resuscitated after CA, for whom EEG, SEPs and brain CT were available within 24 h. EEG patterns were classified according to American Clinical Neurophysiological Society terminology; SEPs were graded accounting for the cortical responses of each hemisphere; and the grey matter/white matter(GM/WM) ratio was evaluated by brain CT. EEG patterns, SEP findings and GM/WM ratio (with a specificity of 100%) were, individually and in combination, related to poor outcome (death/unresponsive wakefulness state) at 6-month follow-up, using the cerebral performance categories(CPC). RESULTS: EEG, SEPs and brain CT were available in 183/273(67%) patients. Bilateral absent/absent-pathologic(AA/AP) cortical SEPs predicted a poor outcome with a sensitivity of 58.5%. A GM/WM ratio <1.21 predicted a poor outcome with a sensitivity of 50.4%. Isoelectric/burst-suppression EEG patterns predicted a poor outcome with a sensitivity of 43%. If at least one of these poor prognostic patterns was present, sensitivity for an ominous outcome increased to 71.5%. If, in the same subject, two poor prognostic patterns were simultaneously present, sensitivity was 48%. If all three poor prognostic patterns were present, sensitivity decreased by up to 23%. CONCLUSION: In this population, in which life-sustaining treatments were never suspended, the combination of EEG, SEPs and brain CT improved the sensitivity, maintaining the specificity of poor outcome prediction.

Is brain computed tomography combined with somatosensory evoked potentials useful in the prediction of brain death after cardiac arrest?

BACKGROUND: Brain death (BD) in coma after cardiac arrest (CA) is difficult to predict. Basal ganglia gray matter/white matter (GM/WM) ratio density and somatosensory evoked potentials (SEPs) may differentiate patients evolving toward BD. METHODS: We used SEPs and brain computed tomography (CT) after coma onset, within the first 24hours. RESULTS: Of the 160 patients included in the study, 22 (14%) evolved toward BD. SEP patterns predicted BD (ROC area=0.82, P<0.0001). The combination of SEP patterns, bilaterally absent (AA) and absent on one hemisphere and pathological on the other (AP), predicted BD with a sensitivity of 100% and a specificity of 62.3%, with a positive likelihood ratio of 2.65. The GM/WM ratio predicted BD (ROC area=0.68, P=0.01). A GM/WM ratio <1.07 had a sensitivity of 30.4%, a specificity of 94.9%, and a positive likelihood ratio of 6.27. The combination of SEP and CT findings did not increase the prediction of BD. CONCLUSION: SEPs and brain CT within 24hours predicted BD after CA. Severe SEP findings (SEP patterns: AA, AP) identified a subset of patients in whom BD could occur. Brain CT (GM/WM ratio in basal ganglia) predicted an early evolution toward BD with high specificity but lower sensitivity.

Predictive patterns of sensory evoked potentials in comatose brain injured patients evolving to brain death.

OBJECTIVE: To assess whether Somatosensory Evoked Potentials (SEPs), recorded within 24h after ICU admission, are reliable predictors of brain death (BD) in comatose patients with acquired brain injury of various aetiologies. METHODS: SEPs were classified as absent (A), pathological (P), and normal (N). Considering SEP recordings from both hemispheres, 6 patterns were identified: NN, NP, PP, NA, AP, and AA. The final endpoint was BD. RESULTS: Of the 203 patients included in the study, 70 (34%) evolved toward BD. The survival analysis indicated that the combination of SEP patterns in a two-graded scale (grade 1: NN-NP-PP-NA, and grade 2: AP-AA), allowed for prediction of BD with the best accuracy. This aggregation predicted BD with a sensitivity of 75.7% (CI: 64-84), a specificity of 76.6% (CI: 68-83), a positive predictive value of 64.2% (CI: 53-74) and a negative predictive value of 84.3% (CI: 77-90) in overall patients, and with a sensitivity of 75.0% (CI: 63-84), a specificity of 84.9% (CI: 75-90), a positive predictive value of 77.5% (CI: 63-88) and a negative predictive value of 84.3% (CI: 74-91) when excluding cardiac arrest. CONCLUSION: It is worth including SEPs, in association with other investigations and clinical signs, in prognostic scores of BD. The early identification of patients at high risk of evolving towards BD could help physicians to optimise management.