The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Vanagaite J Vingen - One of the best experts on this subject based on the ideXlab platform.
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visual long latency auditory and brainstem auditory Evoked Potentials in migraine relation to pattern size stimulus intensity sound and light discomfort thresholds and pre attack state
Cephalalgia, 2000Co-Authors: Trond Sand, Vanagaite J VingenAbstract:We aimed to estimate primary Sensory Evoked Potential (EP) amplitude, amplitude–intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate th...
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visual long latency auditory and brainstem auditory Evoked Potentials in migraine relation to pattern size stimulus intensity sound and light discomfort thresholds and pre attack state
Cephalalgia, 2000Co-Authors: Trond Sand, Vanagaite J VingenAbstract:We aimed to estimate primary Sensory Evoked Potential (EP) amplitude, amplitude-intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate the possible relation to check size, sound and light discomfort thresholds, and the time to the next attack. Amplitudes of cortical visual Evoked Potentials (VEP, check size 8' and 33'), cortical long latency auditory Evoked Potential (AEP NIP1; 40, 55 and 70 dB SL tones) and brainstem auditory Evoked Potential (BAEP wave IV-V; 40, 55 and 65 dB SL clicks) were recorded and analysed in a blind and balanced design. The difference between the response to the first and the second half of the stimulus sequence was used as a measure of habituation. Twenty-one migraine patients (16 women and five men, mean age 39.3 years, six with aura, 15 without aura) and 22 sex- and age-matched healthy control subjects were studied (18 women and four men, mean age 39.5 years). Low sound discomfort threshold correlated significantly with low levels of BAEP wave IV-V amplitude habituation (r = -0.30, P = 0.05). VEP an AEP amplitudes, habituation, and amplitude-intensity function (ASF) slopes did not differ between groups when ANOVA main factors were considered. Control group VEP habituation was found for small check stimuli (P = 0.04), while potentiation was observed for medium sized checks (P = 0.02). The eight migraine patients who experienced headache within 24 h after the test tended to have increased BAEP wave IV-V ASF slopes (P = 0.08). This subgroup did also have a significant VEP habituation to small checks (P = 0.04). No correlation was found between different modalities. These results suggest that: (i) VEP habituation/potentiation state and brainstem activatio state may depend on the attack-interval cycle in migraine; (ii) VEP habituation/ potentiation may depend on spatial stimulus frequency; (iii) phonophobia (and possibly photophobia) may depend more on subcortical (brainstem) function than on cortical mechanisms; (iv) low cortical preactivation in migraine could not be confirmed; (v) EP habituation and ASF analysis may reflect Sensory modality-specific, not generalized, central nervous system states in migraine and healthy control subjects.
Christian Madl - One of the best experts on this subject based on the ideXlab platform.
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impaired subcortical and cortical Sensory Evoked Potential pathways in septic patients
Critical Care Medicine, 2002Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, Georg Funk, Edith Bauer, Peter Schenk, Klaus Ratheiser, Christian MadlAbstract:Objective: Sensory Evoked Potential (SEP) peak latencies were recorded in order to evaluate the incidence and severity of septic encephalopathy, testing the hypothesis that the occurrence of septic encephalopathy is more frequent than generally assumed. Design: Prospective cohort study. Setting: Medical intensive care unit of a university hospital. Patients: Sixty-eight critically ill patients were studied within 48 hrs after the development of severe sepsis (n = 41) or septic shock (n = 27). Interventions: None. Measurements and Main Results: Septic encephalopathy was defined as prolongation of SEP peak latencies beyond the upper limit of the reference range of subcortical (N13-N20 interpeak latency) and cortical SEP pathways (N20-N70 interpeak latency), as well as asymmetry of peak latencies marked by the presence of subclinical cerebral focal signs. Subcortical SEP pathways were impaired in 34% and cortical SEP pathways in 84% of all patients. The prolongation of the cortical SEP pathway correlated with the Acute Physiology and Chronic Health Evaluation III score (r 2 = 0.23; p <.0001). SEP peak latencies did not differ in patients with severe sepsis compared with those with septic shock. Subclinical cerebral focal signs were present in 24% of the subcortical SEP pathways and in 6% of the cortical SEP pathways. Conclusions: Septic encephalopathy occurs more frequently than generally assumed, and its severity is associated with the severity of illness. The impairment of subcortical and cortical SEP pathways was not different between patients with severe sepsis and those with septic shock.
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Impaired subcortical and cortical Sensory Evoked Potential pathways in septic patients
Critical care medicine, 2002Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, Georg Funk, Edith Bauer, Peter Schenk, Klaus Ratheiser, Christian MadlAbstract:Objective: Sensory Evoked Potential (SEP) peak latencies were recorded in order to evaluate the incidence and severity of septic encephalopathy, testing the hypothesis that the occurrence of septic encephalopathy is more frequent than generally assumed. Design: Prospective cohort study. Setting: Medical intensive care unit of a university hospital. Patients: Sixty-eight critically ill patients were studied within 48 hrs after the development of severe sepsis (n = 41) or septic shock (n = 27). Interventions: None. Measurements and Main Results: Septic encephalopathy was defined as prolongation of SEP peak latencies beyond the upper limit of the reference range of subcortical (N13-N20 interpeak latency) and cortical SEP pathways (N20-N70 interpeak latency), as well as asymmetry of peak latencies marked by the presence of subclinical cerebral focal signs. Subcortical SEP pathways were impaired in 34% and cortical SEP pathways in 84% of all patients. The prolongation of the cortical SEP pathway correlated with the Acute Physiology and Chronic Health Evaluation III score (r 2 = 0.23; p
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Time-dependency of Sensory Evoked Potentials in comatose cardiac arrest survivors
Intensive care medicine, 2001Co-Authors: Alexandra Gendo, Christian Zauner, Ludwig Kramer, Michael Häfner, Georg-christian Funk, Fritz Sterz, Michael Holzer, E. Bauer, Christian MadlAbstract:Objective: To assess the validity of early Sensory Evoked Potential (SEP) recording for reliable outcome prediction in comatose cardiac arrest survivors within 48 h after restoration of spontaneous circulation (ROSC). Design and setting: Prospective cohort study in a medical intensive care unit of a university hospital. Patients: Twenty-five comatose, mechanically ventilated patients following cardiopulmonary resuscitation Measurements and results: Median nerve short- and long-latency SEP were recorded 4, 12, 24, and 48 h after ROSC. Cortical N20 peak latency and cervicomedullary conduction time decreased (improved) significantly between 4, 12, and 24 h after resuscitation in 22 of the enrolled patients. There was no further change in short-latency SEP at 48 h. The cortical N70 peak was initially detectable in seven patients. The number of patients with increased N70 peak increased to 11 at 12 h and 14 at 24 h; there was no further change at 48 h. Specificity of the N70 peak latency (critical cutoff 130 ms) increased from 0.43 at 4 h to 1.0 at 24 h after ROSC. Sensitivity decreased from 1.0 at 4 h to 0.83 at 24 h after ROSC. Conclusion: Within 24 h after ROSC there was a significant improvement in SEP. Therefore we recommend allowing a period of at least 24 h after cardiopulmonary resuscitation for obtaining a reliable prognosis based on SEP.
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metabolic encephalopathy in critically ill patients suffering from septic or nonseptic multiple organ failure
Critical Care Medicine, 2000Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, A Kranz, Georg Grimm, Christian MadlAbstract:OBJECTIVE: Evaluation of changes in the peak latencies of Sensory Evoked Potentials in different patient groups, to evaluate differences in metabolic encephalopathy of critically ill patients with multiple organ failure as a result of septic or nonseptic conditions. DESIGN: Prospective cohort study. SETTING: Intensive care units of the university hospital, Vienna. PATIENTS: Patients (n = 103) treated on an intensive care unit because of multiple organ failure with additional metabolic encephalopathy. Multiple organ failure was induced by sepsis (group A; n = 56), surgery (group B; n = 29), or both (group C; n = 18). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Metabolic encephalopathy was determined by measuring median nerve-stimulated short-latency and long-latency Sensory Evoked Potentials. No differences in the peak latencies of the Sensory Evoked Potentials were detected among the groups. Septic patients had a N70 peak latency of 131+/-21 msecs, nonseptic postsurgical patients of 132+/-17 msecs, and septic postsurgical patients of 134+/-17 msecs. The cervicomedullary N13 to cortical N20 conduction times were 6.4+/-1 msec, 6.4+/-1.4 msecs, and 6.8+/-1.2 msecs, respectively. All measured peak latencies were significantly prolonged compared with peak latencies of healthy controls. The severity of illness assessed by the Acute Physiology and Chronic Health Evaluation III score was not different between the three groups. An increase of the delay of N70 peak latencies was significantly correlated with the severity of illness (r2 = .15; p < .00005). CONCLUSION: There was no difference in Sensory Evoked Potential measurements detectable among septic patients with multiple organ failure, nonseptic postsurgical patients with multiple organ failure, and septic postsurgical patients with multiple organ failure. The N70 peak latency was significantly correlated with the severity of illness but not with the presence or absence of sepsis. In postsurgical patients with multiple organ failure and superimposed sepsis, the N70 peak latencies were not further prolonged compared with postsurgical patients without sepsis.
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Detection of subclinical brain dysfunction by Sensory Evoked Potentials in patients with severe diabetic ketoacidosis
Intensive care medicine, 1997Co-Authors: Edith Eisenhuber, Ludwig Kramer, Christian Madl, Klaus Ratheiser, Georg GrimmAbstract:Objective: Subclinical brain dysfunction is a Potentially deleterious complication of diabetic ketoacidosis but is rarely recognized. Thus, we investigated the diagnostic value of Sensory Evoked Potentials for detecting subclinical brain dysfunction in patients with diabetic ketoacidosis. Design: Prospective trial. Setting: Intensive care unit in a university hospital. Patients: 5 neurologically asymptomatic patients (Glasgow Coma Scale score 15, slight drowsiness; aged 20 to 66 years) with an established diagnosis of severe diabetic ketoacidosis were studied. Measurements and results: Short- and long-latency Sensory Evoked Potentials were recorded within 2 h of initiation of therapy for ketoacidosis and 7 days after normalization of ketoacidosis, respectively. Two hours after starting therapy, Sensory Evoked Potential peak latencies were prolonged in all five patients compared to age-matched healthy subjects [cervical N 13 to cortical N 20 interpeak latency of short-latency Evoked Potentials (mean) 5.8 vs 5.3 ms, p < 0.05; N 35 peak latency 40 vs 34 ms, p < 0.05; N 70 peak latency of long-latency Evoked Potentials 102 vs 76 ms, p < 0.01]. In all five patients, cervical N 13 to cortical N 20 interpeak latency and N 35 and N 70 peak latency reverted to normal 7 days after recovery from diabetic ketoacidosis. Conclusions: Our study indicates that the recording of Sensory Evoked Potentials is a sensitive method of detecting subclinical brain dysfunction in patients with severe diabetic ketoacidosis. Since Sensory Evoked Potentials were significantly prolonged in all five patients, this strongly suggests that subclinical brain dysfunction occurs more frequently than is generally recognized.
Michael G Fehlings - One of the best experts on this subject based on the ideXlab platform.
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delayed post injury administration of riluzole is neuroprotective in a preclinical rodent model of cervical spinal cord injury
Journal of Neurotrauma, 2013Co-Authors: Kajana Satkunendrarajah, Yang Teng, Diana S L Chow, Josef Buttigieg, Michael G FehlingsAbstract:Abstract Riluzole, a sodium/glutamate antagonist has shown promise as a neuroprotective agent. It is licensed for amyotrophic lateral sclerosis and is in clinical trial development for spinal cord injury (SCI). This study investigated the therapeutic time-window and pharmacokinetics of riluzole in a rodent model of cervical SCI. Rats were treated with riluzole (8 mg/kg) at 1 hour (P1) and 3 hours (P3) after injury or with vehicle. Afterward, P1 and P3 groups received riluzole (6 (mg/kg) every 12 hours for 7 days. Both P1 and P3 animals had significant improvements in locomotor recovery as measured by open field locomotion (BBB score, BBB subscore). Von Frey stimuli did not reveal an increase in at level or below level mechanical allodynia. Sensory-Evoked Potential recordings and quantification of axonal cytoskeleton demonstrated a riluzole-mediated improvement in axonal integrity and function. Histopathological and retrograde tracing studies demonstrated that delayed administration leads to tissue preserv...
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real time continuous intraoperative electromyographic and somatoSensory Evoked Potential recordings in spinal surgery correlation of clinical and electrophysiologic findings in a prospective consecutive series of 213 cases
Spine, 2004Co-Authors: Thorsteinn Gunnarsson, Roger Sarjeant, Andrei V Krassioukov, Michael G FehlingsAbstract:Study Design. Retrospective analysis of a prospectively accrued series of 213 consecutive patients who underwent intraoperative neurophysiologic monitoring with electromyography and somatosensony-Evoked Potentials during thoracolumbar spine surgery. Objectives. To study the incidence of significant intra-operative electrophysiologic changes and new postoperative neurologic deficits. of Background Data. Continuous intraoperative electromyography and somatoSensory-Evoked Potentials are frequently used in spinal surgery to prevent neural injury. However, only limited data are available on the sensitivity, specificity, and predictive values of intra-operative electrophysiologic changes with regard to the occurrence of new postoperative neurologic deficits. Methods. We examined data on patients who underwent intraoperative monitoring with continuous lower limb electromyography and somatoSensory-Evoked Potentials. The analysis focused on the correlation of intra-operative electrophysiologic changes with the development of new neurologic deficits. RESULTS. A total of 213 patients underwent surgery on a total of 378 levels, 32.4% underwent an instrumented fusion. Significant electromyograph activation was observed in 77.5% of the patients and significant somato-Sensory-Evoked Potential changes in 6.6%. Fourteen patients (6.6%) had new postoperative neurologic symptoms. Of those, all had significant electromyograph activation, but only 4 had significant somatoSensory-Evoked Potential changes, Intraoperative electromyograph activation bad a sensitivity of 100% and a specific ity of 23.7% for the detection of a new postoperative neurologic deficit. SomatoSensory-Evoked Potentials had a sensitivity of 28.6% and specificity of 94.7%. Conclusions. Intraoperative electromyographic activation has a high sensitivity for the detection of a new posstoperative neurologic deficit but a low specifificity. In contrast, somatoSensory Evoked Potentials have low sensitivity but high specificity. Combined intraoperative neurophysiologic monitoring with electromyography and somatoSensory-Evoked Potentials is helpful for predicting and possibly preventing neurologic injury during thoracolumbar spine surgery.
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use of Sensory Evoked Potentials recorded from the human occiput for intraoperative physiologic monitoring of the spinal cord
Spine, 1995Co-Authors: R J Hurlbe, Michael G Fehlings, M S MoncadaAbstract:STUDY DESIGN This is a report of a prospective case series. OBJECTIVE The purpose of this study was to determine whether Evoked Potential activity recorded from occipital scalp electrodes in humans is similar to that recorded in animals, and to evaluate the independence of this activity from the classical somatoSensory-Evoked Potential. SUMMARY OF BACKGROUND DATA Intraoperative somatoSensory-Evoked Potentials can be of limited usefulness in predicting spinal cord injury because they are transmitted primarily through the dorsal columns, and therefore do not reflect integrity of important ventral pathways. It recently has been shown in animal studies that a Sensory-Evoked Potential recorded from the cerebellum is mediated via ventral tracts and is useful as an adjunct to the somatoSensory-Evoked Potential in spinal cord monitoring. METHODS Twenty-five patients undergoing spinal or posterior fossa surgery were consecutively entered into the study. Evoked responses were recorded transcranially from over the cerebellar hemispheres and from the vertex. Recordings were made directly from the surface of the cerebellar hemispheres in seven of these patients. RESULTS Waveforms could be recorded and reproduced in all but one of the patients. The overall appearance of the occipital recordings was similar to the appearance of responses obtained in animals. The mean latency of the first negative peak recorded from the ipsilateral occiput was 33.0 msec (standard deviation, 3.7 msec) compared with 52.4 msec (standard deviation, 6.1 msec) for the somatoSensory-Evoked Potential. In addition, the amplitude of this response (0.35 microV; standard deviation, 0.20 microV) was independent of the amplitude of the somatoSensory-Evoked Potential (0.76 microV; standard deviation, 0.69 microV). In five cases, one Evoked Potential could be recorded in the absence of the other. Recordings from the surface of the cerebellum were of the same morphology, but of greater amplitude than the transcranial recordings. CONCLUSION Evoked responses can be reliably recorded from over the occiput and show characteristics independent of the classical somatoSensory-Evoked Potential. These responses are very similar to the cerebellar-Evoked Potential recently characterized in animals and may provide a method for assessing the physiologic integrity of the ventral tracts of the spinal cord in humans.
Trond Sand - One of the best experts on this subject based on the ideXlab platform.
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visual long latency auditory and brainstem auditory Evoked Potentials in migraine relation to pattern size stimulus intensity sound and light discomfort thresholds and pre attack state
Cephalalgia, 2000Co-Authors: Trond Sand, Vanagaite J VingenAbstract:We aimed to estimate primary Sensory Evoked Potential (EP) amplitude, amplitude–intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate th...
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visual long latency auditory and brainstem auditory Evoked Potentials in migraine relation to pattern size stimulus intensity sound and light discomfort thresholds and pre attack state
Cephalalgia, 2000Co-Authors: Trond Sand, Vanagaite J VingenAbstract:We aimed to estimate primary Sensory Evoked Potential (EP) amplitude, amplitude-intensity functions and habituation in migraine patients compared with healthy control subjects and to investigate the possible relation to check size, sound and light discomfort thresholds, and the time to the next attack. Amplitudes of cortical visual Evoked Potentials (VEP, check size 8' and 33'), cortical long latency auditory Evoked Potential (AEP NIP1; 40, 55 and 70 dB SL tones) and brainstem auditory Evoked Potential (BAEP wave IV-V; 40, 55 and 65 dB SL clicks) were recorded and analysed in a blind and balanced design. The difference between the response to the first and the second half of the stimulus sequence was used as a measure of habituation. Twenty-one migraine patients (16 women and five men, mean age 39.3 years, six with aura, 15 without aura) and 22 sex- and age-matched healthy control subjects were studied (18 women and four men, mean age 39.5 years). Low sound discomfort threshold correlated significantly with low levels of BAEP wave IV-V amplitude habituation (r = -0.30, P = 0.05). VEP an AEP amplitudes, habituation, and amplitude-intensity function (ASF) slopes did not differ between groups when ANOVA main factors were considered. Control group VEP habituation was found for small check stimuli (P = 0.04), while potentiation was observed for medium sized checks (P = 0.02). The eight migraine patients who experienced headache within 24 h after the test tended to have increased BAEP wave IV-V ASF slopes (P = 0.08). This subgroup did also have a significant VEP habituation to small checks (P = 0.04). No correlation was found between different modalities. These results suggest that: (i) VEP habituation/potentiation state and brainstem activatio state may depend on the attack-interval cycle in migraine; (ii) VEP habituation/ potentiation may depend on spatial stimulus frequency; (iii) phonophobia (and possibly photophobia) may depend more on subcortical (brainstem) function than on cortical mechanisms; (iv) low cortical preactivation in migraine could not be confirmed; (v) EP habituation and ASF analysis may reflect Sensory modality-specific, not generalized, central nervous system states in migraine and healthy control subjects.
Ludwig Kramer - One of the best experts on this subject based on the ideXlab platform.
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impaired subcortical and cortical Sensory Evoked Potential pathways in septic patients
Critical Care Medicine, 2002Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, Georg Funk, Edith Bauer, Peter Schenk, Klaus Ratheiser, Christian MadlAbstract:Objective: Sensory Evoked Potential (SEP) peak latencies were recorded in order to evaluate the incidence and severity of septic encephalopathy, testing the hypothesis that the occurrence of septic encephalopathy is more frequent than generally assumed. Design: Prospective cohort study. Setting: Medical intensive care unit of a university hospital. Patients: Sixty-eight critically ill patients were studied within 48 hrs after the development of severe sepsis (n = 41) or septic shock (n = 27). Interventions: None. Measurements and Main Results: Septic encephalopathy was defined as prolongation of SEP peak latencies beyond the upper limit of the reference range of subcortical (N13-N20 interpeak latency) and cortical SEP pathways (N20-N70 interpeak latency), as well as asymmetry of peak latencies marked by the presence of subclinical cerebral focal signs. Subcortical SEP pathways were impaired in 34% and cortical SEP pathways in 84% of all patients. The prolongation of the cortical SEP pathway correlated with the Acute Physiology and Chronic Health Evaluation III score (r 2 = 0.23; p <.0001). SEP peak latencies did not differ in patients with severe sepsis compared with those with septic shock. Subclinical cerebral focal signs were present in 24% of the subcortical SEP pathways and in 6% of the cortical SEP pathways. Conclusions: Septic encephalopathy occurs more frequently than generally assumed, and its severity is associated with the severity of illness. The impairment of subcortical and cortical SEP pathways was not different between patients with severe sepsis and those with septic shock.
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Impaired subcortical and cortical Sensory Evoked Potential pathways in septic patients
Critical care medicine, 2002Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, Georg Funk, Edith Bauer, Peter Schenk, Klaus Ratheiser, Christian MadlAbstract:Objective: Sensory Evoked Potential (SEP) peak latencies were recorded in order to evaluate the incidence and severity of septic encephalopathy, testing the hypothesis that the occurrence of septic encephalopathy is more frequent than generally assumed. Design: Prospective cohort study. Setting: Medical intensive care unit of a university hospital. Patients: Sixty-eight critically ill patients were studied within 48 hrs after the development of severe sepsis (n = 41) or septic shock (n = 27). Interventions: None. Measurements and Main Results: Septic encephalopathy was defined as prolongation of SEP peak latencies beyond the upper limit of the reference range of subcortical (N13-N20 interpeak latency) and cortical SEP pathways (N20-N70 interpeak latency), as well as asymmetry of peak latencies marked by the presence of subclinical cerebral focal signs. Subcortical SEP pathways were impaired in 34% and cortical SEP pathways in 84% of all patients. The prolongation of the cortical SEP pathway correlated with the Acute Physiology and Chronic Health Evaluation III score (r 2 = 0.23; p
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Time-dependency of Sensory Evoked Potentials in comatose cardiac arrest survivors
Intensive care medicine, 2001Co-Authors: Alexandra Gendo, Christian Zauner, Ludwig Kramer, Michael Häfner, Georg-christian Funk, Fritz Sterz, Michael Holzer, E. Bauer, Christian MadlAbstract:Objective: To assess the validity of early Sensory Evoked Potential (SEP) recording for reliable outcome prediction in comatose cardiac arrest survivors within 48 h after restoration of spontaneous circulation (ROSC). Design and setting: Prospective cohort study in a medical intensive care unit of a university hospital. Patients: Twenty-five comatose, mechanically ventilated patients following cardiopulmonary resuscitation Measurements and results: Median nerve short- and long-latency SEP were recorded 4, 12, 24, and 48 h after ROSC. Cortical N20 peak latency and cervicomedullary conduction time decreased (improved) significantly between 4, 12, and 24 h after resuscitation in 22 of the enrolled patients. There was no further change in short-latency SEP at 48 h. The cortical N70 peak was initially detectable in seven patients. The number of patients with increased N70 peak increased to 11 at 12 h and 14 at 24 h; there was no further change at 48 h. Specificity of the N70 peak latency (critical cutoff 130 ms) increased from 0.43 at 4 h to 1.0 at 24 h after ROSC. Sensitivity decreased from 1.0 at 4 h to 0.83 at 24 h after ROSC. Conclusion: Within 24 h after ROSC there was a significant improvement in SEP. Therefore we recommend allowing a period of at least 24 h after cardiopulmonary resuscitation for obtaining a reliable prognosis based on SEP.
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metabolic encephalopathy in critically ill patients suffering from septic or nonseptic multiple organ failure
Critical Care Medicine, 2000Co-Authors: Christian Zauner, Alexandra Gendo, Ludwig Kramer, A Kranz, Georg Grimm, Christian MadlAbstract:OBJECTIVE: Evaluation of changes in the peak latencies of Sensory Evoked Potentials in different patient groups, to evaluate differences in metabolic encephalopathy of critically ill patients with multiple organ failure as a result of septic or nonseptic conditions. DESIGN: Prospective cohort study. SETTING: Intensive care units of the university hospital, Vienna. PATIENTS: Patients (n = 103) treated on an intensive care unit because of multiple organ failure with additional metabolic encephalopathy. Multiple organ failure was induced by sepsis (group A; n = 56), surgery (group B; n = 29), or both (group C; n = 18). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Metabolic encephalopathy was determined by measuring median nerve-stimulated short-latency and long-latency Sensory Evoked Potentials. No differences in the peak latencies of the Sensory Evoked Potentials were detected among the groups. Septic patients had a N70 peak latency of 131+/-21 msecs, nonseptic postsurgical patients of 132+/-17 msecs, and septic postsurgical patients of 134+/-17 msecs. The cervicomedullary N13 to cortical N20 conduction times were 6.4+/-1 msec, 6.4+/-1.4 msecs, and 6.8+/-1.2 msecs, respectively. All measured peak latencies were significantly prolonged compared with peak latencies of healthy controls. The severity of illness assessed by the Acute Physiology and Chronic Health Evaluation III score was not different between the three groups. An increase of the delay of N70 peak latencies was significantly correlated with the severity of illness (r2 = .15; p < .00005). CONCLUSION: There was no difference in Sensory Evoked Potential measurements detectable among septic patients with multiple organ failure, nonseptic postsurgical patients with multiple organ failure, and septic postsurgical patients with multiple organ failure. The N70 peak latency was significantly correlated with the severity of illness but not with the presence or absence of sepsis. In postsurgical patients with multiple organ failure and superimposed sepsis, the N70 peak latencies were not further prolonged compared with postsurgical patients without sepsis.
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Detection of subclinical brain dysfunction by Sensory Evoked Potentials in patients with severe diabetic ketoacidosis
Intensive care medicine, 1997Co-Authors: Edith Eisenhuber, Ludwig Kramer, Christian Madl, Klaus Ratheiser, Georg GrimmAbstract:Objective: Subclinical brain dysfunction is a Potentially deleterious complication of diabetic ketoacidosis but is rarely recognized. Thus, we investigated the diagnostic value of Sensory Evoked Potentials for detecting subclinical brain dysfunction in patients with diabetic ketoacidosis. Design: Prospective trial. Setting: Intensive care unit in a university hospital. Patients: 5 neurologically asymptomatic patients (Glasgow Coma Scale score 15, slight drowsiness; aged 20 to 66 years) with an established diagnosis of severe diabetic ketoacidosis were studied. Measurements and results: Short- and long-latency Sensory Evoked Potentials were recorded within 2 h of initiation of therapy for ketoacidosis and 7 days after normalization of ketoacidosis, respectively. Two hours after starting therapy, Sensory Evoked Potential peak latencies were prolonged in all five patients compared to age-matched healthy subjects [cervical N 13 to cortical N 20 interpeak latency of short-latency Evoked Potentials (mean) 5.8 vs 5.3 ms, p < 0.05; N 35 peak latency 40 vs 34 ms, p < 0.05; N 70 peak latency of long-latency Evoked Potentials 102 vs 76 ms, p < 0.01]. In all five patients, cervical N 13 to cortical N 20 interpeak latency and N 35 and N 70 peak latency reverted to normal 7 days after recovery from diabetic ketoacidosis. Conclusions: Our study indicates that the recording of Sensory Evoked Potentials is a sensitive method of detecting subclinical brain dysfunction in patients with severe diabetic ketoacidosis. Since Sensory Evoked Potentials were significantly prolonged in all five patients, this strongly suggests that subclinical brain dysfunction occurs more frequently than is generally recognized.
