What is the best test to predict outcome after prolonged cardiac arrest?

Reliability of the Glasgow Coma Scale for the emergency department evaluation of poisoned patients

The Glasgow Coma Scale (GCS) was developed for monitoring the mental status of head-injured patients in the intensive care unit. The purpose of this study is to determine the inter-rater reliability of the GCS for poisoning patients in the emergency department. Methods: This was a prospective, observational study. Two observers used a standard assessment checklist to determine the GCS of suspected poisoning patients. Inter-rater reliability was assessed with a weighted Kappa score. Results: A total of 39 patients were enrolled. Weighted kappa for the total GCS demonstrated excellent agreement. Agreement was also good for each component of the score. Conclusion: The GCS is a reliable tool for the evaluation of mental status of poisoning patients in the emergency department.

Electrophysiologic monitoring in acute brain injury

To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications.

Recommendations on the use of EEG monitoring in critically ill patients: consensus statement from the neurointensive care section of the ESICM

OBJECTIVES

Recommendations for EEG monitoring in the ICU are lacking. The Neurointensive Care Section of the ESICM assembled a multidisciplinary group to establish consensus recommendations on the use of EEG in the ICU.

METHODS

A systematic review was performed and 42 studies were included. Data were extracted using the PICO approach, including: (a) population, i.e. ICU patients with at least one of the following: traumatic brain injury, subarachnoid hemorrhage, intracerebral hemorrhage, stroke, coma after cardiac arrest, septic and metabolic encephalopathy, encephalitis, and status epilepticus; (b) intervention, i.e. EEG monitoring of at least 30 min duration; (c) control, i.e. intermittent vs. continuous EEG, as no studies compared patients with a specific clinical condition, with and without EEG monitoring; (d) outcome endpoints, i.e. seizure detection, ischemia detection, and prognostication. After selection, evidence was classified and recommendations developed using the GRADE system.

RECOMMENDATIONS

The panel recommends EEG in generalized convulsive status epilepticus and to rule out nonconvulsive seizures in brain-injured patients and in comatose ICU patients without primary brain injury who have unexplained and persistent altered consciousness. We suggest EEG to detect ischemia in comatose patients with subarachnoid hemorrhage and to improve prognostication of coma after cardiac arrest. We recommend continuous over intermittent EEG for refractory status epilepticus and suggest it for patients with status epilepticus and suspected ongoing seizures and for comatose patients with unexplained and persistent altered consciousness.

CONCLUSIONS

EEG monitoring is an important diagnostic tool for specific indications. Further data are necessary to understand its potential for ischemia assessment and coma prognostication.

Cardiac arrest and post resuscitation of the brain

Primary out-of-hospital cardiac arrest in childhood is rare but survival is a little better for children than for adults, although the prognosis for infants is very poor. Hypoxic-ischaemic encephalopathy after in-hospital cardiac arrest in children undergoing complicated treatment for previously untreatable conditions is now a common problem and is probably increasing. An additional ischaemic insult worsens the prognosis for other encephalopathies, such as that occurring after accidental or non-accidental head injury. For near-drowning, the prognosis is often good, provided that cardiopulmonary resuscitation (CPR) is commenced immediately, and the child gasps within 40 minutes of rescue and regains consciousness soon afterwards. The prognosis is much worse for the nearly drowned child admitted to casualty or the emergency room deeply unconscious with fixed dilated pupils, requiring continuing CPR and with an arterial pH <7, especially if there is little recovery by the time of admission to the intensive care unit. The use of adrenaline, sodium bicarbonate and calcium appears to worsen prognosis. Neurophysiology, specifically serial electroencephalography and evoked potentials, is the most useful tool prognostically, although neuroimaging and biomarkers may play a role. In a series of 89 patients studied after cardiac arrest in three London centres between 1982 and 1985, 39% recovered consciousness within one month. Twenty seven percent died a cardiac death whilst in coma, and the outcome in the remainder was either brain death or vegetative state. EEG and initial pH were the best predictors of outcome in this study. Seizures affected one third and were associated with deterioration and worse outcome. The advent of extracorporeal membrane oxygenation (ECMO) and the positive results of hypothermia trials in neonates and adults have rekindled interest in timely management of this important group of patients.

The role of the immuno-inflammatory response in patients after cardiac arrest

INTRODUCTION

The aim of the research was to assess whether concentrations of inflammatory markers in blood of patients after cardiac arrest (CA) are related to their clinical state and survival.

MATERIAL AND METHODS

Forty-six patients, aged 63 ±12 years, 21 of them after out-of-hospital CA and 25 after in-hospital CA, were enrolled in the study. Twenty-five patients survived and were discharged from hospital (CA-S); 21 died during hospitalization (CA-D). The clinical state of the patients was evaluated by the Glasgow Coma Scale (GCS) and the Acute Physiology and Chronic Health Evaluation II (APACHE II). On the day immediately after CA (day 1) and on the following day (day 2) the plasma concentration of high specific C-reactive protein (hs-CRP), tumour necrosis factor (TNF)-α, interleukin-10 and interleukin-6 (Ile-6) were measured.

RESULTS

In CA-D patients, compared with CA-S, a significantly higher concentration of hs-CRP (on day 1, 19 ±5 vs. 15 ±4; on day 2, 21 ±3 vs. 16 ±5 mg/l, p < 0.001) and Ile-6 (on day 1, 24.9 ±19.8 vs. 9.2 ±11.3; on day 2, 24.2 ±19.7 vs. 6.9 ±6.8 IU/ml, p < 0.001) was found. The level of TNF-α was greater in CA-D on day 1 (0.42 ±0.75 vs. 0.18 ±0.21 IU/ml, p < 0.04). Concentrations of hs-CRP and Ile-6 were correlated with the scores of GCS and APACHE II. Using logistic regression analysis and ROC curves the prognostic value of hs-CRP and Ile-6 for survival was proven.

CONCLUSIONS

Post-cardiac arrest immuno-inflammatory response, reflected mainly in elevated plasma concentration of hs-CRP and Ile-6, is not only correlated with patients' clinical state but also with prediction of survival.

Trajectory analysis of serum biomarker concentrations facilitates outcome prediction after pediatric traumatic and hypoxemic brain injury

Traumatic brain injury (TBI) and hypoxic ischemic encephalopathy (HIE) are leading causes of morbidity and mortality in children. Several studies over the past several years have evaluated the use of serum biomarkers to predict outcome after pediatric brain injury. These studies have all used simple point estimates such as initial and peak biomarker concentrations to predict outcome. However, this approach does not recognize patterns of change over time. Trajectory analysis is a type of analysis which can capture variance in biomarker concentrations over time and has been used with success in the social sciences. We used trajectory analysis to evaluate the ability of the serum concentrations of 3 brain-specific biomarkers - S100B, neuron-specific enolase (NSE) and myelin basic protein (MBP) - to predict poor outcome (Glasgow Outcome Scale scores 3-5) after pediatric TBI and HIE. Clinical and biomarker data from 100 children with TBI or HIE were evaluated. For each biomarker, we validated 2-, 3- and 4-group models for outcome prediction, using sensitivity and specificity. For S100B, the 3-group model predicted poor outcome with a sensitivity of 59% and specificity of 100%. For NSE, the 3-group model predicted poor outcome with a sensitivity of 48% and specificity of 98%. For MBP, the 3-group model predicted poor outcome with a sensitivity of 73% and specificity of 61%. Thus, when the models predicted a poor outcome, there was a very high probability of a poor outcome. In contrast, 17% of subjects with a poor outcome were predicted to have a good outcome by all 3 biomarker trajectories. These data suggest that trajectory analysis of biomarker data may provide a useful approach for predicting outcome after pediatric brain injury.

Long-term functional outcome and performance status after intensive care unit re-admission: a prospective survey

BACKGROUND

Intensive care unit (ICU) re-admission identifies a high-risk group in terms of hospital mortality, length of stay, and resource utilization. Only hospital and ICU mortality are well described in the literature on critically ill patients needing re-admission.

METHODS

With ethical committee approval, from a prospectively collected database of all admissions to a combined medical and surgical ICU from January 1 to December 31, 2004, we identified all ICU re-admissions from within the hospital and analysed the factors associated with increased incidence of re-admission. At 2-3 yr after discharge, we evaluated the functional outcome of the surviving re-admitted patients as Glasgow Outcome Score (GOS) and Karnofsky index and identified determinants of both mortality and good functional outcome.

RESULTS

Seventy-three (7.4%) of the 1061 patients who survived their first ICU stay were re-admitted during the study period. Of the 73 re-admitted patients, 14 died in ICU, 17 died later in the same hospital stay, and 10 died in the interim. Thus, 32 (43.8%) were alive 2-3 yr after discharge. The median [IQR] GOS of the survivors was 4 (see Mackle and colleagues in One year outcome of intensive care patients with decompensated alcoholic liver disease.

CONCLUSIONS

Although the ICU, hospital, and subsequent mortalities are high in patients after ICU re-admission, most survivors at 2-3 yr had by then made a good functional recovery and were independent.

Variability in agreement between physicians and nurses when measuring the Glasgow Coma Scale in the emergency department limits its clinical usefulness

OBJECTIVE

To assess the interrater reliability of the Glasgow Coma Scale (GCS) between nurses and senior doctors in the ED.

METHODS

This was a prospective observational study with a convenience sample of patients aged 18 or above who presented with a decreased level of consciousness to a tertiary hospital ED. A senior ED doctor (emergency physicians and trainees) and registered nurse each independently scored the patient's GCS in blinded fashion within 15 min of each other. The data were then analysed to determine interrater reliability using the weighted kappa statistic and the size and directions of differences between paired scores were examined.

RESULTS

A total of 108 eligible patients were enrolled, with GCS scores ranging from 3 to 14. Interrater agreement was excellent (weighted kappa > 0.75) for verbal scores and total GCS scores, and intermediate (weighted kappa 0.4-0.75) for motor and eye scores. Total GCS scores differed by more than two points in 10 of the 108 patients. Interrater agreement did not vary substantially across the range of actual numeric GCS scores.

CONCLUSIONS

Although the level of agreement for GCS scores was generally high, a significant proportion of patients had GCS scores which differed by two or more points. This degree of disagreement indicates that clinical decisions should not be based solely on single GCS scores.

Early prediction of individual outcome following cardiopulmonary resuscitation: systematic review

Following resuscitation from cardiorespiratory arrest 80% of patients are comatose. Of these patients, 20% will survive and regain consciousness. Is it possible to predict an individual's long term outcome at presentation and alter management accordingly? This review examines the current medical literature and demonstrates it is impossible to predict immediately outcome from hypoxic-ischaemic coma except in a small subgroup of patients with poor premorbid factors. As individual prognosis cannot be determined in the emergency department all patients who do not have significant premorbid features should proceed to a period of supportive care in the intensive care unit. Therapeutic hypothermia should be considered for these patients.

Are somatosensory evoked potentials the best predictor of outcome after severe brain injury? A systematic review

OBJECTIVE

Many tests have been used to predict outcome following severe brain injury. We compared predictive powers of clinical examination (pupillary responses, motor responses and Glasgow Coma Scale, GCS), electroencephalography (EEG) and computed tomography (CT) to that of somatosensory evoked potentials (SEPs) in a systematic review.

MATERIALS AND METHODS

Medline (1976-2002) and Embase (1980-2002) were searched, manual review of article reference lists was conducted, and authors were contacted. We selected 25 studies addressing the prediction of outcome after severe brain injury using SEPs and either GCS, EEG, CT, pupillary or motor responses. Outcomes were determined for patients with normal or bilaterally absent SEPs and graded measures of GCS, EEG, CT, pupillary responses or motor responses. For favourable outcome prediction SEPs were superior in sensitivity, specificity and positive and negative predictive values, except for pupillary responses which had superior sensitivity and GCS which had higher specificity. SEPs had superior summary receiver operating characteristic curves, with the exception of motor responses, and superior ratio of odds ratios. For unfavourable outcome prediction SEPs were superior to the other tests in sensitivity, specificity and positive and negative predictive values, except for motor and pupillary responses, GCS and CTs which had superior sensitivity. All SEP summary receiver operating characteristic curves and pooled ratio of odds ratios were superior.

CONCLUSIONS

Although imperfect, SEPs appear to be the best single overall predictor of outcome. There is sufficient evidence for clinicians to use SEPs in the prediction of outcome after brain injury.

Brain arrest neurological outcome scale (BrANOS): predicting mortality and severe disability following cardiac arrest

BACKGROUND

To create a predictive scale of neurological outcome following cardiac arrest (CA) that incorporates radiological and clinical markers of brain injury.

METHODS AND RESULTS

Brain arrest neurologic outcome scale (BrANOS) is a prospective 16-point scale. It consisted of three variables: (1) duration of arrest (DAR), (2) reversed Glasgow coma scale (GCS), and (3) Hounsfield unit (HU) ratio on non-contrast CT scan of the head. Reversed GCS score was defined as 15-GCS (best GCS in the first 24 h). HU ratio was defined as the density ratio of the caudate nucleus over the posterior limb of the internal capsule measured on unenhanced CT scan of the brain. We identified 32 comatose patients who had: (1) CT scan performed within 48 h of event; (2) no previous history of either coma, severe head trauma, cardiac arrest or stroke. Primary outcome was defined as alive or dead. Secondary outcome was the Glasgow outcome score recorded on discharge. Patient demographics were collated from retrospective chart review. Patients' mean age was 63 +/- 3 years (mean +/- S.E.M.); 44% were females. Mortality rate was 81%. Mean DAR was 21 +/- 2 min. Survivors had a significantly lower BrANOS score (8 +/- 2 points) compared to non-survivors (13 +/- 1) (P = 0.006). BrANOS was a strong predictor of mortality alone (ROC = 0.86) and mortality with severe disability combined (ROC = 0.9). The scale had a 100% specificity and positive predictive value.

CONCLUSIONS

BrANOS is a reliable predictor of neurological outcome following CA. It is the first scale to incorporate clinical and radiological markers of brain injury.

The use of bispectral index to monitor unconscious children

The use of the Glasgow Coma Scale may be limited by the experience of physicians, errors resulting from subjectivity, the inability of patients to respond, and discontinuity. This study demonstrates that the Bispectral Index scores correlate well with scores from the Glasgow Coma Scale and that Bispectral Index scores can provide real-time, objective, and continuous monitoring of the consciousness level of critically ill children. Sixteen patients with consciousness disturbance, who were admitted to a pediatric intensive care unit of a tertiary university-affiliated children's hospital, were enrolled in this study. The patients received 34 Glasgow Coma Scale assessments and Bispectral Index scores. The age of patients ranged from 10 to 192 months (mean +/- S.E. = 68.4 +/- 12.3 months). Glasgow Coma Scale ranged from 3 to 11 (mean +/- S.E. = 6.3 +/- 0.4), and Bispectral Index score ranged from 0 to 100 (mean +/- S.E. = 55.4 +/- 5.6). A positive correlation was found to exist between Glasgow Coma Scale and Bispectral Index score (r = 0.76, P < 0.001). In conclusion, the Bispectral Index score correlates well with the Glasgow Coma Scale in critically ill children who score between 3 and 11 on the Glasgow Coma Scale.

The EEG in coma

The EEG allows insight into thalamocortical function in comatose patients when this is inaccessible clinically. A single EEG can help with broad diagnostic categorization whereas continuous or serial EEG provides monitoring for unstable and potentially treatable conditions and for monitoring the effects of therapy. The EEG plays a supplemental role in establishing the prognosis in disease states that are capable of causing neuronal death. The most prevalent and problematic of these conditions involves survivors of cardiac arrest who are initially in coma with intact brainstem reflexes. In such patients single EEGs are of 100% specificity for no possibility of recovery of consciousness only for essentially complete generalized suppression (<10 microV) after the first day of the arrest. Several other generalized patterns, including less marked suppression, burst-suppression, epileptiform activity, periodic complexes, and alpha-theta coma patterns, usually but not invariably indicate a poor outcome. Serial EEGs, continuous raw and automated "trending," testing of reactivity, and the inclusion of multiple variables hold promise for an improved role in the prognostic determination in these patients.

Improvement in the information content of the Glasgow Coma Scale for the prediction of full cognitive recovery after head injury using fuzzy logic

BACKGROUND

The objective of this study was to modify the existing Glasgow Coma Scale (GCS) into a fuzzy GCS by using fuzzy information representation and fuzzy inferencing. The study compared the information content of the existing GCS with the new fuzzy GCS for prediction of full cognitive recovery in patients with head injury.

METHODS

A record-based study was conducted at the Government Medical College and Hospital, a tertiary care facility in Nagpur, India. The study, which covered the period from January 1 to December 31, 1997, included 253 patients with head injuries. Opinions of 17 clinical experts who routinely deal with head injury cases were used for the construction of the fuzzy GCS.

RESULTS

By using the max operator for summarization, eye, motor, and verbal stimuli were all significantly associated with the possibility of full cognitive recovery with the fuzzy GCS (P < .001). Nonspecificity of the classical GCS, the min-operated fuzzy GCS, and the max-operated fuzzy GCS was comparable. A reduction in Shannon entropy was maximum with the max-operated fuzzy GCS. Min-operated fuzzy GCS better predicted a lack of full cognitive recovery.

CONCLUSIONS

Fuzzy GCS substantially improves the information content for prediction of the possibility of full cognitive recovery after head injury. Eye, motor, and verbal stimuli all uniquely and significantly contribute to prediction of this possibility. We recommend the use of fuzzy GCS for prediction of the possibility of full cognitive recovery in patients with head injuries.

Medical technology assessment EEG and evoked potentials in the intensive care unit

We review the principal aspects of EEG and evoked potential (EP) neuromonitoring in the intensive care unit. The electrophysiological methods allow functional assessment of comatose patients and can be used (a) as a help to diagnose the origin of coma, (b) as a means to predict outcome, and (c) for monitoring purposes. The combination of the EEG and long-, middle-, and short-latency EPs allows widespread assessment of the cerebral cortex, the brain-stem, and the spinal cord. The EEG and the EP interpretation first requires taking into account non-neurological factors that may interfere with the recorded activities (sensory pathologies, toxic or metabolic problems, body temperature). The sensitivity and the specificity of any neurophysiological technique depend on the etiology of coma. Anoxic comas are associated with a predominantly cortical involvement, while the cortical and brain-stem functions are to be taken into account to interpret the EEG and the EPs in head trauma. The EEG and the EPs can be used to differentiate the comas due to structural lesions from those of metabolic origin, to confirm brain death and help to diagnose psychogenic unresponsiveness or a de-efferented state. While the prognostic value of the EEG is markedly hampered by the widespread use of sedative drugs, it has been possible to design efficient systems based on early- and middle-latency multimodality evoked potentials in anoxic and traumatic comas and, more generally, in all comas associated with an increase of the intracranial pressure. Continuous neuromonitoring techniques are currently under development. They have already been proven useful for the early detection and for the prevention of subclinical seizures, transtentorial herniation, vasospasm, and other causes of brain or spinal-cord ischemia.