Determination of loss of consciousness: a comparison of clinical assessment, bispectral index and electroencephalogram: An observational study.

BACKGROUND: Computer-processed algorithms of encephalographic signals are widely used to assess the depth of anaesthesia. However, data indicate that the bispectral index (BIS), a processed electroencephalography monitoring system, may not be reliable for assessing the depth of anaesthesia. OBJECTIVE: The aim of this study was to evaluate the ability of the BIS monitoring system to assess changes in the level of unconsciousness, specifically during the transition from consciousness to unconsciousness, in patients undergoing total intravenous anaesthesia with propofol. We compared BIS with the electroencephalogram (EEG), and clinical loss of consciousness (LOC) defined as loss of verbal commands and eyelash reflex. DESIGN: This was an observational cohort study. SETTING: University Hospital Linköping, University Hospital Örebro, Finspång Hospital and Kalmar Hospital, Sweden from October 2011 to April 2013. PATIENTS: A total of 35 ASA I patients aged 18 to 49 years were recruited. INTERVENTIONS: The patients underwent total intravenous anaesthesia with propofol and remifentanil for elective day-case surgery. Changes in clinical levels of consciousness were assessed by BIS and compared with assessment of stage 3 neurophysiological activity using the EEG. The plasma concentrations of propofol were measured at clinical LOC and 20 and 30 min after LOC. MAIN OUTCOME MEASURES: The primary outcome was measurement of BIS, EEG and clinical LOC. RESULTS: The median BIS value at clinical LOC was 38 (IQR 30 to 43), and the BIS values varied greatly between patients. There was no correlation between BIS values and EEG stages at clinical LOC (r = -0.1, P = 0.064). Propofol concentration reached a steady state within 20 min. CONCLUSION: There was no statistically significant correlation between BIS and EEG at clinical LOC. BIS monitoring may not be a reliable method for determining LOC. CLINICAL TRIALS REGISTRY: This trial was not registered because registration was not mandatory at the time of the trial.

Assessment of nurse's knowledge about Glasgow coma scale at a university hospital.

OBJECTIVE: To assess knowledge of nurses of emergency services and intensive care units about Glasgow Coma Scale. METHODS: This cross-sectional analytical study included 127 nurses of critical units of an university hospital. We used structured interview with 12 questions to evaluate their knowledge about the scale. Association of Knowledge with professionals' sociodemographic variables were verified by the Fisher-test, χ2 and likelihood ratio. RESULTS: Most of participants were women mean aged 31.1 years, they had graduated more than 5 years previously, and had 1 to 3 years of work experience. In the assessment of best score possible for Glasgow scale (question 3) nurses who had graduate more than 5 years ago presented a lower percentage success rate (p=0.0476). However, in the question 7, which evaluated what interval of the scale indicated moderate severity of brain trauma injury, those with more years of experience had higher percentage of correct answers (p=0.0251). In addition, nurses from emergency service had more correct answers than nurses from intensive care unit (p=0.0143) in the same question. Nurses graduated for more than 5 years ago had a lower percentage of correct answers in question 7 (p=0.0161). Nurses with more work experience had a better score (p=0.0119) to identify how assessment of motor response should be started. CONCLUSION: Number of year since graduation, experience, and work at critical care units interfered in nurses' knowledge about the scale, which indicates the need of training. OBJETIVO: Avaliar o conhecimento de enfermeiros de unidades críticas, serviços de emergência e unidades de terapia intensiva em relação à escala de coma de Glasgow. MÉTODOS: Estudo transversal e analítico com 127 enfermeiros de unidades críticas de um hospital universitário. Utilizou-se entrevista estruturada com 12 questões que avaliaram conhecimento sobre a escala. Associação do conhecimento com variáveis sociodemográficas dos profissionais foi verificada pelo teste de Fisher, teste χ2 e razão de verossimilhança. RESULTADOS: Houve predominância de mulheres, média de idade de 31,1 anos, especialistas, mais de 5 anos de formado e experiência profissional de 1 a 3 anos. Na avaliação do melhor escore possível para pontuação na escala (questão 3), enfermeiros com tempo de formação maior que 5 anos apresentaram menor porcentual de acertos (p=0,0476). Em relação à questão 7, que avaliou qual intervalo da escala indicava gravidade moderada do trauma craniencefálico, observou-se que quanto maior o tempo de experiência, maior o porcentual de acertos (p=0,0251), sendo que enfermeiros do serviço de emergência tiveram mais acertos nessa questão em relação aos das unidades de terapia intensiva (p=0,0143). Além disso, enfermeiros formados há mais de 5 anos apresentaram menor porcentual de acertos nessa questão (p=0,0161). Quando se identificou como deve ser iniciada a avaliação da resposta motora, enfermeiros com maior tempo de trabalho na unidade apresentaram mais acertos (p=0,0119). CONCLUSÃO: Tempo de formação, experiência e trabalho na unidade interferiu no conhecimento de enfermeiros sobre a escala, evidenciando necessidade de capacitação.

Assessment of nurse's knowledge about Glasgow coma scale at a university hospital / Avaliação do conhecimento de enfermeiros sobre a escala de coma de Glasgow em um hospital universitário

ABSTRACT Objective To assess knowledge of nurses of emergency services and intensive care units about Glasgow Coma Scale. Methods This cross-sectional analytical study included 127 nurses of critical units of an university hospital. We used structured interview with 12 questions to evaluate their knowledge about the scale. Association of Knowledge with professionals’ sociodemographic variables were verified by the Fisher-test, χ2 and likelihood ratio. Results Most of participants were women mean aged 31.1 years, they had graduated more than 5 years previously, and had 1 to 3 years of work experience. In the assessment of best score possible for Glasgow scale (question 3) nurses who had graduate more than 5 years ago presented a lower percentage success rate (p=0.0476). However, in the question 7, which evaluated what interval of the scale indicated moderate severity of brain trauma injury, those with more years of experience had higher percentage of correct answers (p=0.0251). In addition, nurses from emergency service had more correct answers than nurses from intensive care unit (p=0.0143) in the same question. Nurses graduated for more than 5 years ago had a lower percentage of correct answers in question 7 (p=0.0161). Nurses with more work experience had a better score (p=0.0119) to identify how assessment of motor response should be started. Conclusion Number of year since graduation, experience, and work at critical care units interfered in nurses’ knowledge about the scale, which indicates the need of training.

RESUMO Objetivo Avaliar o conhecimento de enfermeiros de unidades críticas, serviços de emergência e unidades de terapia intensiva em relação à escala de coma de Glasgow. Métodos Estudo transversal e analítico com 127 enfermeiros de unidades críticas de um hospital universitário. Utilizou-se entrevista estruturada com 12 questões que avaliaram conhecimento sobre a escala. Associação do conhecimento com variáveis sociodemográficas dos profissionais foi verificada pelo teste de Fisher, teste χ2 e razão de verossimilhança. Resultados Houve predominância de mulheres, média de idade de 31,1 anos, especialistas, mais de 5 anos de formado e experiência profissional de 1 a 3 anos. Na avaliação do melhor escore possível para pontuação na escala (questão 3), enfermeiros com tempo de formação maior que 5 anos apresentaram menor porcentual de acertos (p=0,0476). Em relação à questão 7, que avaliou qual intervalo da escala indicava gravidade moderada do trauma craniencefálico, observou-se que quanto maior o tempo de experiência, maior o porcentual de acertos (p=0,0251), sendo que enfermeiros do serviço de emergência tiveram mais acertos nessa questão em relação aos das unidades de terapia intensiva (p=0,0143). Além disso, enfermeiros formados há mais de 5 anos apresentaram menor porcentual de acertos nessa questão (p=0,0161). Quando se identificou como deve ser iniciada a avaliação da resposta motora, enfermeiros com maior tempo de trabalho na unidade apresentaram mais acertos (p=0,0119). Conclusão Tempo de formação, experiência e trabalho na unidade interferiu no conhecimento de enfermeiros sobre a escala, evidenciando necessidade de capacitação.

The assessment of consciousness during partial seizures.

A wide range of controversial definitions and dynamic components surround the multi-dimensional concept of consciousness, with important reflections on the phenomenological description of ictal states relevant to epileptic seizures. The inadequacies of terminology, the insufficient emphasis on the subjective nature of consciousness, as well as the intrinsic limitations of the simple versus complex dichotomy for partial seizures, are to be considered in view of a modern definition of consciousness. In this paper, we review the difficulties encountered by clinicians in assessing the ictal conscious state in patients with epilepsy, and illustrate how a more sophisticated bi-dimensional model of consciousness can prove a valuable conceptual tool for the clinical assessment of ictal consciousness and the categorization of seizures.

Implantable loop recorders are cost-effective when used to investigate transient loss of consciousness which is either suspected to be arrhythmic or remains unexplained.

AIMS: To assess the cost-effectiveness of implantable loop recorders (ILRs) in people with transient loss of consciousness (TLoC), which, after initial assessment and specialist cardiovascular assessment, is either suspected to be arrhythmic in origin or remains unexplained. This analysis was conducted to inform clinical guideline recommendations made by the National Institute for Health and Clinical Excellence (NICE) on the management of TLoC. METHODS AND RESULTS: Decision analytic modelling was used to estimate the costs and benefits of using ILRs compared with a strategy of no further diagnostic testing. Diagnostic outcomes were estimated from a systematic review and used to populate a decision tree model. To capture the main consequences of diagnosis, the costs and benefits of treatment for several clinically significant arrhythmias were estimated within the model. We used a cost-utility approach, in which benefits are measured using quality adjusted life years (QALYs), and took a UK National Health Service (NHS) and personal social services perspective. The cost per QALY was £17,400 in patients with unexplained syncope and £16,400 in patients with suspected arrhythmic syncope. Sensitivity analysis found that the cost-effectiveness estimates are fairly robust despite the areas of uncertainty identified in the evidence and assumptions used to inform the model. CONCLUSIONS: Implantable loop recorder monitoring is likely to be a cost-effective strategy in people presenting to the UK NHS who are experiencing infrequent episodes of TLoC which either remain unexplained or are suspected to be arrhythmic after initial assessment and specialist cardiovascular assessment. Implantable loop recorder monitoring has been recommended by NICE for these populations.

Synopsis of the National Institute for Health and Clinical Excellence Guideline for management of transient loss of consciousness.

DESCRIPTION: Transient loss of consciousness (TLoC) is common and often leads to incorrect diagnosis, unnecessary investigation, or inappropriate choice of specialist referral. In August 2010, the National Institute for Health and Clinical Excellence published a guideline that addressed the initial assessment of and most appropriate specialist referral for persons who have experienced TLoC. The guideline focused on correct diagnosis and relevant specialist referral and did not make treatment recommendations. This synopsis describes the principal recommendations concerning assessment and referral of a patient with TLoC. METHODS: The National Clinical Guideline Centre developed the guidelines by using the standard methodology of the National Institute for Health and Clinical Excellence. A multidisciplinary guideline panel generated review questions, discussed evidence, and formulated recommendations. The panel included a technical team from the National Clinical Guideline Centre, who reviewed and graded all relevant evidence identified from literature searches published in English up to November 2009 and performed health-economic modeling. Both guideline development and final modifications were informed by comments from stakeholders and the public. RECOMMENDATIONS: The panel made clear recommendations regarding the assessment of a person after TLoC, which emphasized the importance of clinical reasoning in diagnosis. Persons with uncomplicated faint, situational syncope, or orthostatic hypotension should receive electrocardiography but do not otherwise require immediate further investigation or specialist referral. Persons with features that suggest epilepsy should be referred for specialist neurologic assessment; brief seizure-like activity was recognized as a common occurrence during syncope that should not be regarded as indicating epilepsy. Persons with a suspected cardiac cause for TLoC or in whom TLoC is unexplained after initial assessment should receive specialist cardiovascular assessment. Guidance was provided on the appropriate choices of cardiovascular investigation, according to the presenting clinical circumstances.

Assessment of consciousness with electrophysiological and neurological imaging techniques.

PURPOSE OF REVIEW: Brain MRI (diffusion tensor imaging and spectroscopy) and functional neuroimaging (PET, functional MRI, EEG and evoked potential studies) are changing our understanding of patients with disorders of consciousness encountered after coma such as the 'vegetative' or minimally conscious states. RECENT FINDINGS: Increasing evidence from functional neuroimaging and electrophysiology demonstrates some residual cognitive processing in a subgroup of patients who clinically fail to show any response to commands, leading to the recent proposal of 'unresponsive wakefulness syndrome' as an alternative name for patients previously coined 'vegetative' or 'apallic'. SUMMARY: Consciousness can be viewed as the emergent property of the collective behavior of widespread thalamocortical frontoparietal network connectivity. Data from physiological, pharmacological and pathological alterations of consciousness provide evidence in favor of this hypothesis. Increasing our understanding of the neural correlates of consciousness is helping clinicians to do a better job in terms of diagnosis, prognosis and finally treatment and drug development for these severely brain-damaged patients. The current challenge remains to continue translating this research from the bench to the bedside. Only well controlled large multicentric neuroimaging and electrophysiology studies will enable to identify which paraclinical diagnostic or prognostic test is necessary for our routine evidence-based assessment of individuals with disorders of consciousness.

Continuous peritransplant assessment of consciousness using bispectral index monitoring for patients with fulminant hepatic failure undergoing urgent liver transplantation.

BACKGROUND: Rapid deterioration of consciousness is a critical situation for patients with fulminant hepatic failure (FHF). Bispectral (BIS) index was derived from electroencephalography parameters, primarily to monitor the depth of unconsciousness. AIM: To assess the usability of peritransplant BIS monitoring in patients with FHF. METHODS: A prospective study using peritransplant BIS monitoring was performed in 26 patients with FHF undergoing urgent liver transplantation (LT). RESULTS: Pre-transplant Child-Pugh score was 12.2 +/- 1.0; model for end-stage liver disease score was 32.4 +/- 4.4; Glasgow coma score (GCS) was 9.9 +/- 1.3; and BIS index was 44.0 +/- 6.7. Pre-transplant sedation significantly decreased BIS index. After LT, all patients having endotracheal intubation recovered consciousness within one to three d and showed progressive increase in BIS index, which appeared slightly earlier and was more evident than the increase in derived GCS score. There was a significant correlation between BIS index and derived GCS scores (r(2) = 0.648). Timing of eye opening to voice was matched with BIS index of 66.3 +/- 10.4 and occurred 12.7 +/- 8.3 h after passing BIS index of 50. CONCLUSION: These results suggest that BIS monitoring is a non-invasive, simple, easy-to-interpret method, which is useful in assessing peritransplant state of consciousness. BIS monitoring may therefore be a useful tool during peritransplant intensive care for patients with FHF showing hepatic encephalopathy.

Transient loss of consciousness 1: causes and impact of misdiagnosis.

Part 1 of this two-part unit outlines the various possible causes of transient loss of consciousness (blackouts), the importance of accurate diagnosis and the impact of misdiagnosis. It also discusses the establishment of specialist clinics in order to help with diagnosis and management.

Morbilidad materna aguda y severa en Guatemala / Severe acute maternal morbidity in Guatemala

Objetivo: determinar el estado de conciencia materno en la morbilidad severa y aguda durante el embarazo, parto, aborto y puerperio relacionándolo con el pronóstico y evolución al ingresar a un centro hospitalario. Diseño: estudio de seguimiento prospectivo, de base poblacional, con lugar definido geográficamente. Lugar: dos hospitales públicos y tres hospitales de la seguridad social del departamento de Guatemala. Población: 39,361 partos hospitalarios en un período de 12 meses. Método: análisis univariado, bivariado y multivariado, así como pruebas de regresión logística comparando los casos de morbilidad severa y aguda clasificadas concientes e inconscientes.

High diagnostic yield and accuracy of history, physical examination, and ECG in patients with transient loss of consciousness in FAST: the Fainting Assessment study.

BACKGROUND: Transient loss of consciousness (TLOC) is a common clinical problem. OBJECTIVE: The aim of this study was to assess the yield and accuracy of the initial evaluation, consisting of standardized history, physical examination, and ECG performed by attending physicians in patients with TLOC. METHODS AND RESULTS: Five hundred and three adult patients (mean age 53 +/- 19; 56% male) presenting with TLOC to the Academic Medical Center Amsterdam between February 2000 and May 2002 were included in this study. After initial evaluation, the physician made a certain, a highly likely (>80% certain), or no initial diagnosis. Initially undiagnosed patients received additional cardiological testing, additional history taking, and autonomic function tests. After 2 years of follow-up, an expert committee determined the final diagnoses. Two-year follow-up was obtained in 99% of the patients. The yield of certain diagnoses after the initial evaluation was 24%, increasing to 63% after including the highly likely diagnoses. The diagnostic accuracy of the initial certain diagnoses was 93% (95% CI 87-97%), decreasing to 88% (95% CI 84-91%) after inclusion of the initial highly likely diagnoses. CONCLUSION: Attending physicians can make a diagnosis based on initial evaluation in 63% of patients with TLOC, with an overall diagnostic accuracy of 88%. The use of additional testing, beyond history, physical examination, and ECG can be avoided in many patients with TLOC.

Facilitated assessment of unconsciousness from morphologic changes in the bilateral posterior tibial nerve cortical somatosensory evoked potential under total intravenous propofol anesthesia during spine surgery.

OBJECTIVE: To describe a unique morphologic feature of the bilateral posterior tibial nerve cortical somatosensory evoked potential, the S-wave, which varies systematically with propofol infusion rate and which appears to be useful in guiding adequate propofol concentration levels during spine surgery. METHODS: Two illustrative cases were selected from a pool of 15,000 pediatric and adult patients (ages 8-85 years) who were undergoing corrective spine surgery in operating rooms of university and community hospitals. Anesthesia was maintained with a continuous intravenous infusion of propofol (125-225 microg/kg/min) along with intermittent boluses of narcotic and midazolam (1.0-2.0 mg) as needed. Characteristic metamorphosis of the bilateral posterior tibial nerve cortical somatosensory evoked potential, highlighted by the emergence of an additional middle-latency component labeled the S-wave, served as a neurophysiological marker of "light" propofol anesthesia prompting elevation of propofol infusion rate or bolus injection. RESULTS: The S-wave was routinely abolished with increased propofol infusion rate or bolus injection. In all instances increased propofol concentration levels produced a characteristic morphologic change in the posterior tibial nerve cortical somatosensory evoked potential consistent with a return to adequate anesthetic depth. Selected cases presented herein compare the S-wave technique to BIS and illustrate the usefulness of the S-wave in identifying inadequate depth of propofol anesthesia. CONCLUSIONS: The bilateral posterior tibial nerve cortical somatosensory evoked potential changes its morphology in predictable fashion with decreased depth of propofol anesthesia, allowing for anticipation of imminent anesthetic "lightening." It serves as a useful cross-check to Bispectral Index (BIS) or other "level of consciousness" EEG-based algorithms for monitoring depth of propofol anesthesia during prolonged corrective spine surgery.

Simple bedside assessment of level of consciousness: comparison of two simple assessment scales with the Glasgow Coma scale.

Neurological assessment is an essential component of early warning scores used to identify seriously ill ward patients. We investigated how two simple scales (ACDU - Alert, Confused, Drowsy, Unresponsive; and AVPU - Alert, responds to Voice, responds to Pain, Unresponsive) compared to each other and also to the more complicated Glasgow Coma Scale (GCS). Neurosurgical nurses recorded patients' conscious level with each of the three scales. Over 7 months, 1020 analysable measurements were collected. Both simple scales identified distinct GCS ranges, although some overlap occurred (p < 0.001). Median GCS scores associated with AVPU were 15, 13, 8 and 6 and for ACDU were 15, 13, 10 and 6. The median values of ACDU were more evenly distributed than AVPU and may therefore be better at identifying early deteriorations in conscious level when they occur in critically ill ward patients.

[ABC--DER TIP--STIMMT. Primary assessment of consciousness disorders]. / ABC--DER TIP--STIMMT. Erstbeurteilung von Bewusstsseinsstörungen

A unconscious patient produces fear for laymen and uncertainty for professionals. Because acute changes in consciousness, that means changes in alertness or thinking, are challenges for every physician. Therefore the assessment of a unconscious patient demand a structural action. In this paper a reliable procedure is proposed in three steps. As a mnemonic serves the sentence "ABC (1st step)--DER TIP (2nd step)--STIMMT (3rd step)". The first step contains the ABC, which is usual in emergency medicine. In the second step neurological and other disabilities are noticed. An in the third step one tries, related to the findings from step one and two as well as from further examinations (CCT, lumbal puncture, lab-examines, ...), to find potential reasons for the unconsciousness of a patient.

Disability versus futility in rationing health care services: defining medical futility based on permanent unconsciousness--PVS, coma, and anencephaly.

All societies must ration health care services in the face of unlimited demand. The concept of medical futility may appear to be an uncontroversial means by which to ration services. Depending upon how it is applied, however, limiting services based on alleged medical futility may violate prohibitions against disability-based discrimination. In particular, use of medical futility to require removal of life-sustaining interventions has been held to violate the Americans with Disabilities Act. The ADA protects both people with disabilities who are conscious and people in unconscious states, such as permanent vegetative state (PVS), coma, and anencephaly. Ultimately, as the number of people in permanently unconscious states increases, our society will have to recognize that consciousness is an essential characteristic defining human beings and determining whether a legal right to unlimited life-sustaining intervention should apply. This article proposes to define medical futility to preclude life-sustaining interventions after a stated period of permanent unconsciousness and to redefine the end of life consistently as neocortical death.

The assessment of orientation following concussion in athletes.

The purpose of this study was to investigate the sensitivity of orientation and recent memory questions in the diagnosis of concussion. In a prospective study over 7 consecutive years (1985-1991), all players at a professional Australian Rules Football club who sustained a concussive injury (n = 28) were administered a set of questions evaluating orientation and recent memory. Concussion was diagnosed independently on the basis of loss or disturbance of consciousness and clinical symptoms. A control group of age-matched nonconcussed players was administered the same set of questions. The results showed that items evaluating recently acquired information were more sensitive in the assessment of concussion than standard orientation items. The relative sensitivity of orientation questions must be considered when they are used in the clinical diagnosis of concussion in sport.