Electroencephalographic prediction of anoxic brain damage after resuscitation from cardiac arrest in patients with acute myocardial infarction

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.

The EEG as an independent indicator of mortality and healthcare utilization

OBJECTIVE

Determine whether EEG findings could be used as an independent prognostic indicator of outcomes in a general patient population.

METHODS

A large electronic medical record was used to merge the results of EEG studies with the results of medical evaluations including: medications prescribed, medical diagnoses, blood test results, imaging results, and outcomes in 3193 patients. Univariable and multivariable analyses were undertaken to determine whether the EEG had a role in predicting outcomes independent of other factors in a clinic population.

RESULTS

Patients with abnormal EEG's had significantly higher mortalities, greater cost of healthcare and more evaluation visits than patients with normal EEG's in every age range independent of the presence other medical conditions. The costs associated with caring for a patient with an abnormal EEG were roughly three times that of a patient with a normal EEG. The risk of death in the multivariable analysis was 3.7 times higher in patients with an abnormal EEG than in patients with a normal EEG.

CONCLUSIONS

In addition to its traditional diagnostic implications, the EEG may convey information about general level of illness and the cost of caring for patients.

SIGNIFICANCE

Certain EEG findings may identify high risk patients and thus may open the door to possible interventions.

Emergency room resuscitation of patients with cardiac arrest outside hospital. Outcome and immediate prognosis in 319 patients

Resuscitation was attempted in 319 patients brought to hospital with cardiac arrest during a 5-year period. Primary successful results were achieved in 50 patients (15.7%). Twelve patients were long-term survivors (3.4%), 10 of whom had normal brain function, whereas 2 had mild cerebral dysfunction. To improve prognostication in patients with initially successful resuscitation, Bayes' theorem was applied using 4 clinical findings after 24 hours' treatment: reactions to painful stimuli, pupillary size, light reactions and BP, Bayes' theorem as well as coma depth after 24 hours gave valuable information regarding individual prognosis.

Early electrophysiologic markers predict functional outcome associated with temperature manipulation after cardiac arrest in rats

OBJECTIVE

Therapeutic hypothermia after cardiac arrest improves survival and functional outcomes, whereas hyperthermia is harmful. The optimal method of tracking the effect of temperature on neurologic recovery after cardiac arrest has not been elucidated. We studied the recovery of cortical electrical function by quantitative electroencephalography after 7-min asphyxial cardiac arrest, using information quantity (IQ).

DESIGN

Laboratory investigation.

SETTING

University medical school and animal research facility.

SUBJECTS

A total of 28 male Wistar rats.

INTERVENTIONS

Using an asphyxial cardiac arrest rodent model, we tracked quantitative electroencephalography of 6-hr immediate postresuscitation hypothermia (at 33 degrees C), normothermia (37 degrees C), or hyperthermia (39 degrees C) (n = 8 per group). Neurologic recovery was evaluated using the Neurologic Deficit Score. Four rats were included as a sham control group.

MEASUREMENTS AND MAIN RESULTS

Greater recovery of IQ was found in rats treated with hypothermia (IQ = 0.74), compared with normothermia (IQ = 0.60) and hyperthermia (IQ = 0.56) (p < .001). Analysis at different intervals demonstrated a significant separation of IQ scores among the temperature groups within the first 2 hrs postresuscitation (p < .01). IQ values of >0.523 at 60 mins postresuscitation predicted good neurologic outcome (72-hr Neurologic Deficit Score of > or = 60), with a specificity of 100% and sensitivity of 81.8%. IQ was also significantly lower in rats that died prematurely compared with survivors (p < .001). IQ values correlated strongly with 72-hr Neurologic Deficit Score as early as 30 mins post-cardiac arrest (Pearson's correlation 0.735, p < .01) and maintained a significant association throughout the 72-hr experiment. No IQ difference was noted in sham rats with temperature manipulation.

CONCLUSIONS

The enhanced recovery provided by hypothermia and the detrimental effect by hyperthermia were robustly detected by early quantitative electroencephalographic markers. IQ values during the first 2 hrs after cardiac arrest accurately predicted neurologic outcome at 72 hrs.

Quantitative EEG and neurological recovery with therapeutic hypothermia after asphyxial cardiac arrest in rats

We test the hypothesis that quantitative electroencephalogram (qEEG) can be used to objectively assess functional electrophysiological recovery of brain after hypothermia in an asphyxial cardiac arrest rodent model. Twenty-eight rats were randomly subjected to 7-min (n = 14) and 9-min (n = 14) asphyxia times. One half of each group (n = 7) was randomly subjected to hypothermia (T = 33 degrees C for 12 h) and the other half (n = 7) to normothermia (T = 37 degrees C). Continuous physiologic monitoring of blood pressure, EEG, and core body temperature monitoring and intermittent arterial blood gas (ABG) analysis was undertaken. Neurological recovery after resuscitation was monitored using serial Neurological Deficit Score (NDS) calculation and qEEG analysis. Information Quantity (IQ), a previously validated measure of relative EEG entropy, was employed to monitor electrical recovery. The experiment demonstrated greater recovery of IQ in rats treated with hypothermia compared to normothermic controls in both injury groups (P < 0.05). The 72-h NDS of the hypothermia group was also significantly improved compared to the normothermia group (P < 0.05). IQ values measured at 4 h had a strong correlation with the primary neurological outcome measure, 72-h NDS score (Pearson correlation 0.746, 2-tailed significance <0.001). IQ is sensitive to the acceleration of neurological recovery as measured NDS after asphyxial cardiac arrest known to occur with induced hypothermia. These results demonstrate the potential utility of qEEG-IQ to track the response to neuroprotective hypothermia during the early phase of recovery from cardiac arrest.

Clinical neurophysiologic monitoring and brain injury from cardiac arrest

Electrophysiologic testing continues to play an important role in injury stratification and prognostication in patients who are comatose after cardiac arrest. As discussed previously, however, the adage about treating whole patients, not just the numbers, is relevant in this situation. EEG and SSEP can offer high specificity for discerning poor prognosis as long as they are applied to appropriate patient populations. As discussed previously, EEG and SSEP patterns change during the first hours to days after cardiac arrest and negative prognostic information should not be based solely on studies performed during the first 24 hours. Both electrophysiologic techniques also are susceptible to artifacts that may worsen the electrical patterns artificially and suggest a falsely poor prognosis. EEG is suppressed by anesthetic agents and hypothermia, both of which may produce ECS and burst suppression. Patients who experience respiratory arrest from a toxic ingestion of narcotics or barbiturates, in particular, may present with high-grade EEG patterns initially. Many patients also receive anesthetic medications at the time of tracheal intubation, which may linger beyond their normal half-life in patients who have hepatic or renal insufficiency or concurrent use of interacting medications. SSEP is much less susceptible to sedative anesthetic agents, but hypothermia is demonstrated to prolong evoked potential latencies. As therapeutic hypothermia becomes more common after cardiac arrest, the effect of temperature on electrophysiologic testing needs to be taken into account. The publications discussed previously also emphasize the need to adjust the prognostic value of electro-physiologic tests to the pretest probability of meaningful neurologic recovery in individual patients. Clearly, grade I EEG patterns and normal N20 potentials indicate a much better prognosis in patients who have a short du-ration of cardiac arrest, short duration of coma after resuscitation, and when the studies are performed within the first few days. In patients who remain in coma days after resuscitation and lack appropriate brainstem reflexes, however, even the most normal appearing electrophysiologic patterns do little to change the overall prognosis. Aside from prognostication, electrophysiologic testing holds great promise in defining the basic anatomy and physiology of coma emergence after cardiac arrest. In addition, quantitative EEG and automated evoked potentials have the potential to render these tools less subjective and arcane and more applicable for monitoring patients in the period during and immediately after resuscitation. Quantitative EEG also has great potential asa tool to define the time window for neuroprotective intervention and the means to track the response to such therapies in real time.

Observations on comatose survivors of cardiopulmonary resuscitation with generalized myoclonus

Background

There is only limited data on improvements of critical medical care is resulting in a better outcome of comatose survivors of cardiopulmonary resuscitation (CPR) with generalized myoclonus. There is also a paucity of data on the temporal dynamics of electroenephalographic (EEG) abnormalities in these patients.

Methods

Serial EEG examinations were done in 50 comatose survivors of CPR with generalized myoclonus seen over an 8 years period.

Results

Generalized myoclonus occurred within 24 hours after CPR. It was associated with burst-suppression EEG (n = 42), continuous generalized epileptiform discharges (n = 5), alpha-coma-EEG (n = 52), and low amplitude (10 μV <) recording (n = 1). Except in 3 patients, these EEG-patterns were followed by another of these always nonreactive patterns within one day, mainly alpha-coma-EEG (n = 10) and continuous generalized epileptiform discharges (n = 9). Serial recordings disclosed a variety of EEG-sequences composed of these EEG-patterns, finally leading to isoelectric or flat recordings. Forty-five patients died within 2 weeks, 5 patients survived and remained in a permanent vegetative state.

Conclusion

Generalized myoclonus in comatose survivors of CPR still implies a poor outcome despite advances in critical care medicine. Anticonvulsive drugs are usually ineffective. All postanoxic EEG-patterns are transient and followed by a variety of EEG sequences composed of different EEG patterns, each of which is recognized as an unfavourable sign. Different EEG-patterns in anoxic encephalopathy may reflect different forms of neocortical dysfunction, which occur at different stages of a dynamic process finally leading to severe neuronal loss.

Early electroencephalographic findings in patients with anoxic encephalopathy after cardiopulmonary arrest and successful resusitation

This study investigated whether or not early electroencephalographic (EEG) findings and brain computed tomographic (CT) features reflect the prognosis of comatose patients for 48 h after cardiopulmonary resuscitation (CPR). EEGs and brain CT scans were collected from 21 patients within 72 h after CPR. The EEG findings were classified according to the five Hockaday grades. The Glasgow outcome scale (GOS) applied 3 months after CPR was used for prognosis. Of the nine patients with grade 1 and 2 EEGs, eight had a good outcome (five recovered satisfactorily and three remained moderately disabled). Of the eight patients with grade 4 and 5 EEGs, seven had a poor outcome (three died and four remained in a persistent vegetative state). On the other hand, there was no correlation between early CT features and prognosis except for two severe cases, one whose gray/white matter interface had disappeared and the other with relatively increased density of the thalami, brain stem and cerebellum. These findings suggest that EEG is more useful than CT scan as a diagnostic tool for anoxic encephalopathy after CPR.

The Utstein template and the effect of in-hospital decisions: the impact of do-not-attempt resuscitation status on survival to discharge statistics

BACKGROUND

Variables for reporting outcome of pre-hospital cardiac arrest have been delineated in the Utstein style template. The primary outcome statistic is survival to hospital discharge (SHD). The template allows comparisons of pre-hospital care systems and has been used to determine the benefit of pre-hospital interventions. Post-resuscitation care has not been standardized and in-hospital events that affect SHD are not considered in the template.

STUDY PURPOSE

To determine the frequency and timing with which do-not-attempt resuscitation (DNAR) status is conferred following resuscitation from pre-hospital cardiac arrest and to assess the impact of this action on SHD.

METHODS

A 4-year retrospective, observational cohort study of all adult patients successfully resuscitated from nontraumatic pre-hospital cardiac arrest and admitted to a single municipal teaching hospital. Study variables included age, witnessed arrest, bystander cardiopulmonary resuscitation (CPR), initial rhythm documented by paramedics, hospital admission rate, frequency and time at which DNAR status was conferred, and SHD.

RESULTS

Four hundred and eighteen adult patients experienced pre-hospital arrest and received standard advanced cardiac life support interventions during the study period. Seventy-nine patients (19%; 95% confidence interval (CI), 15-23%) survived to be admitted to the hospital. Fifty-four of these patients (68%; 96% CI, 57-78%) were subsequently placed in DNAR status. Only one of these patients had a living will or advanced directive prior to cardiopulmonary arrest. In 37 DNAR patients (68%; 95% CI, 54-81%), DNAR status was conferred within 24 h of hospital admission. For patients made DNAR within 24 h of admission, 38% had a witnessed arrest, 22% had ventricular fibrillation as the first documented arrest rhythm, and 29% received bystander CPR. When patients made DNAR are included in the calculation of SHD rate, the SHD rate for the study period was 5.3% (95% CI, 3.3-7.8%). If DNAR patients are excluded, the SHD was 6.1% (95% CI, 3.8-9.0%), representing a 15% increase in SHD rate.

CONCLUSION

In-hospital care and medical decision making are not considered in the Utstein template and can have a significant effect on reported survival statistics. When assessing the benefit of pre-hospital interventions, it may be preferable to consider survival to hospital admission as the primary outcome statistic until such time as post-resuscitation care after hospital admission is rigidly standardized.

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.

Postanoxic alpha (theta) coma: a reappraisal of its prognostic significance

OBJECTIVES

To appraise the controversial prognostic significance of postanoxic alpha or theta coma (ATC).

METHODS

We prospectively assessed 14 comatose patients with ATC after cardiac arrest by means of a protocol which included repeated clinical examinations, EEG, and median somatosensory evoked potentials (SEP). Good outcome was defined by the reappearance of cognition (Glasgow outcome scale 3-5) at any time during the 1 year follow-up.

RESULTS

Nine of 14 patients had a monotonous, frontally accentuated and a reactive alpha (theta) EEG activity (complete ATC). In these patients ATC was recorded a mean of 47 h after resuscitation, the mean Glasgow coma scale (GCS) was 4 at 48 h, and early cortical SEPs were altered or absent in 5 of 7 patients. All nine patients died. In five of 14 patients the alpha (theta) EEG activity was either not monotonous, partially reactive or posteriorly dominant (incomplete ATC). In these patients ATC was recorded a mean of 43 h after resuscitation, the mean GCS was 8 at 48 h, and early cortical SEP were normal in 4 of 5 patients. Three of 5 patients regained cognition, two of them remained however dependent in activities of everyday life.

CONCLUSIONS

This study and a review 283 cases of postanoxic ATC reported in the literature suggest the existence of incomplete and complete variants of postanoxic ATC. Whereas complete ATC is invariably associated with a poor outcome, full recovery is possible in patients with incomplete ATC. The combination of EEG, clinical, and SEP findings improves the prognostic accuracy of postanoxic ATC.

The course of circulatory and cerebral recovery after circulatory arrest: influence of pre-arrest, arrest and post-arrest factors

We evaluated the influence of pre-arrest, arrest and post-arrest factors on circulatory and neurological recovery for up to 1 year following circulatory arrest of cardio-pulmonary aetiology in 231 patients. Initially, all patients were unconscious and 106 had some cortical activity recorded in the immediate post-resuscitation EEG (Group I), while 125 had no such activity initially (Group II). The following variables were explored: age, sex, medical history, cause and location of arrest, initial cardiac dysrhythmia, duration of life support, metabolic acidosis, pulse-pressure product and heart pump function capacity early after resuscitation. Outcome measures were duration and quality of circulatory survival, cause of death, neurological recovery and ultimate outcome. First year survival was 33% in Group I and 16% in Group II. Severe heart failure and brain death occurred mainly in Group II. Circulatory recovery was negatively influenced by out-of-hospital arrest, metabolic acidosis and pulse-pressure products below 150. Neurological recovery was negatively influenced by initial dysrhythmias other than ventricular fibrillation, pulse-pressure products below 150, post-arrest heart failure and/or pulmonary complications. It seems that circulatory and cerebral outcomes are mainly determined by the global ischaemic insults sustained during the circulatory arrest period.

Prediction of neurological outcome after cardiopulmonary resuscitation

In 231 patients with circulatory arrest of primary cardiovascular or pulmonary aetiology guidelines were established for predicting neurological outcome within the first year after cardiopulmonary resuscitation. Outcome measures were brain death, persistent unconsciousness, persistent disability after awakening and complete recovery. A total of 116 patients remained unconscious while 115 regained consciousness. Brain stem areflexia with apnoea (brain death) was demonstrated in 40 patients. No other finding per se could predict a specific outcome. The time for recovery of individual neurological functions seemed to be the key to prognostication. Testing the caloric vestibular reflex or stereotypic reactivity thus differentiated patients regaining consciousness from those remaining unconscious, with positive predictive values of 0.79 and 0.77 at 1 h and negative values of 1.0 and 0.97 at 24 h as compared with 50/50 prior odds. The presence of speech at 24 h or the ability to cope with personal necessities at 72 h predicted complete recovery with positive predictive values of 0.91 and 0.92 as compared with prior odds of 0.17, whereas, the negative predictive values never exceeded prior odds of 0.83.

Systematic review of early prediction of poor outcome in anoxic-ischaemic coma

BACKGROUND

Studies to assess the prognostic value of early neurological and neurophysiological findings in patients with anoxic-ischaemic coma have not led to precise, generally accepted, prognostic rules. We did a systematic review of the relevant literature to assess whether such rules could be derived from the combined results of these studies.

METHODS

From Medline and Embase databases we selected studies concerning patients older than 10 years with anoxic-ischaemic coma in which findings from early neurological examination, electroencephalogram (EEG), or somatosensory evoked potentials (SSEP) were related to poor outcome--defined as death or survival in a vegetative state. We selected variables with a specificity of 100% for poor outcome in all studies, and expressed the overall prognostic accuracy of these variables as pooled positive-likelihood ratios and as 95% CIs of the pooled false-positive test rates.

FINDINGS

In 33 studies, 14 prognostic variables were studied, three of which had a specificity of 100%: absence of pupillary light reflexes on day 3 (pooled positive-likelihood ratio 10.5 [95% CI 2.1-52.4]; 95% CI pooled false-positive test rate 0-11.9%); absent motor response to pain on day 3 (16.8 [3.4-84.1]; 0-6.7%); and bilateral absence of early cortical SSEP within the first week (12.0 [5.3-27.6]; 0-2.0%). EEG recordings with an isoelectric or burst-suppression pattern had a specificity of 100% in five of six relevant studies (pooled positive-likelihood ratio 9.0 [2.5-33.1]; 95%CI pooled false-positive test rate 0.2-5.9%). These characteristics were present in 19%, 31%, 33%, and 33% of pooled patient populations, respectively. For the 11 SSEP studies, results did not significantly differ between studies in which the treating physicians were or were not masked from the test result, prospective and retrospective studies, studies with short and long follow-up periods, and studies with high or low overall poor outcome.

INTERPRETATION

SSEP has the smallest CI of its pooled positive-likelihood ratio and its pooled false-positive test rate. Because evoked potentials are also the least susceptible to metabolic changes and drugs, recording of SSEP is the most useful method to predict poor outcome.

The natural course of neurological recovery following cardiopulmonary resuscitation

In 231 patients resuscitated from circulatory arrest of cardiovascular or pulmonary aetiology brain recovery was evaluated by serial neurological and EEG examinations for up to 1 year. One-hundred and sixteen patients never regained consciousness; 115 patients awakened within 30 days, and 40 eventually recovered completely within 90 days. Patients who had electrocortical activity recorded by the immediate post-resuscitation EEG (N = 106), and patients initially without such activity (N=125) pursued the same course of recovery: during unconsciousness, interrelated EEG and neurological findings featured a phase of intermittent cortical activity with postural or stereotypic motor responses followed by a phase of continuous cortical activity with sequential appearances of delta, theta, and alpha activities on EEG accompanied by stereotypic or defensive motor responses. After awakening, the sequential return of motor, sensory, and mental faculties differentiated an early phase of severe disability with orientating eye movements and a bilateral Babinski response from the phase of moderate disability featured by speech, locomotor functions, ability to cope with personal necessities and orientation as to personal data, and a normal plantar response. Finally, orientation as to time, place and role of other persons, and retention and recall, defined the phase of slight/no disability. Abnormal courses were identified by incomplete EEG and neurological recoveries or by the appearance of spikes and sharpwaves in the EEG, or by losses of function.

A rule for early outcome classification of out-of-hospital cardiac arrest patients presenting with ventricular fibrillation

The aim of the study was to develop a scoring system for outcome classification at the start of prehospital first tier resuscitation for patients with cardiac arrest from ventricular fibrillation (VF). We studied a consecutive sample of 100 out-of-hospital cardiac arrest patients, presenting with VF of presumed cardiac etiology on arrival of the first tier (in a two-tiered urban Emergency Medical Services system). The number of patients discharged was 29 ('survivors') and 71 died ('non-survivors'). The electrocardiography (ECG) tracings recorded during resuscitation using a semi-automatic defibrillator were retrospectively analysed. For each patient, VF amplitude in mV (VF_a) and the number of base-line crossings per second (VF_blc) were calculated. Fisher's linear discriminant analysis was applied to discriminate between survivors and non-survivors using the variables VF_a, VF_blc and age. Patients were classed as potential survivors or non-survivors using a survival index = 0.6*(VF_a) + 0.4*(VF_blc)-4.0. If for a given patient the survival index is < 0, he is classified in the non-survivor group, if the survival index is > 0, he is classified in the survivor group. Using this index 79% of the survivors and 70% of the non-survivors could be classified correctly. Adding age to the formula increased the correct classification of survivors to 86 and 73% for the non-survivors. The survival index provides a research tool for the discrimination between potential survivors and non-survivors, which opens the possibility for the development of alternative treatment protocols in cardiac arrest.

EEG detection of nontonic-clonic status epilepticus in patients with altered consciousness

Subtypes of status epilepticus (SE) without tonic-clonic convulsions (nontonic-clonic SE) present as altered consciousness sometimes with subtle motor activity and are important to consider in the differential diagnosis of patients with unexplained altered consciousness. Other patients may have altered consciousness with intermittent ictal activity on electroencephalography (EEG) that represents probable SE, but have other medical conditions that may be contributing to altered consciousness. EEG is the only reliable way to make the diagnosis of nontonic-clonic SE and we make emergency EEG available on a 24-h basis at our hospital. To determine how often definite or probable nontonic-clonic SE was detected by EEG we prospectively collected data on all cases where physicians ordered EEG to evaluate altered consciousness or possible SE. Out of 198 cases with altered consciousness but no clinical convulsions, 74 (37%) showed EEG and clinical evidence of definite or probable nontonic-clonic SE. Forty-two episodes (57%) were probable or definite complex partial SE, 29 (39%) were probable or definite subtle generalized SE, and three (4%) were myoclonic SE. In 23 SE cases altered consciousness was the only clinical sign at the time of diagnosis; subtle motor activity was present in 36 others. Neither clinical signs nor prior history predicted which patients showed SE on EEG. Nontonic-clonic SE followed a cerebral infarction in 16 cases. Contrary to other reports, we found no relationship between duration of SE and EEG pattern. Subtle generalized SE occurred most commonly in the setting of a diffuse brain injury rather than evolving from convulsive SE. This study demonstrates that nontonic-clonic SE is a common finding in patients with unexplained altered consciousness and EEG is necessary in the evaluation of these patients.

[Alpha coma: rectrospective presentation of 20 cases]

Alpha coma is a relatively rare variety of EEG resulting from diffuse cerebral anoxia, focal brainstem lesions, metabolic disturbances or intoxications. It is a monotonous, unreactive and anteriorly predominant activity of less than 50 microV and of 8 to 13 Hz. Twenty cases of alpha coma are reported: 16 resulting from anoxic encephalopathy, 2 from brain stem strokes, and 2 from metabolic encephalopathy. Cardiac arrest was the main cause of alpha coma (10 cases); a large number of patients (7 cases) died, or have survived with severe neurologic deficits (2 cases). In 2 cases there was a metabolic-toxic cause (benzodiazepines and parathion intoxication). The 2 patients with pontomesencephalic haemorrhage died. The physiopathogenicity of alpha coma, which remains obscure, is also discussed.

Myocardial infarction and patients' wives

When a patient has a myocardial infarction (MI), all aspects of marital function are affected. Soon after the MI, patients' wives experience psychological distress that decreases with time. Illness behaviors among the MI patients' wives increase, and aggressive and sexual impulses are often inhibited. Many families experience changes in members' work status after the husband has an MI, and wives are faced with increased chores. Marital interaction also changes. Dysfunctional marital relationships are associated with a poor psychosocial outcome. Additionally, spousal factors such as dependency are also likely to affect patients. Intervention strategies are best directed to wives at risk for problems.

[Study of cerebral energy metabolism and development of postanoxia coma]

An open prospective study of brain energy metabolism was carried out in 20 consecutive cases of coma occurring after cardiopulmonary arrest (CPA) of various causes. Mean age was 54 years and mean duration of CPA 2.75 min, with a mean of 11 min for resuscitation. Brain energy metabolism was compared with clinical course, electroencephalogram (EEG), and neurological outcome. All the patients were given the usual intensive care: intermittent positive pressure ventilation, haemodynamic control, sedation with benzodiazepines, neuromuscular paralysis, anticonvulsants, mannitol. A clinical examination and an EEG were carried out daily, 4 h after all drugs which might interfere with these investigations or brain energy metabolism had been stopped (except for anticonvulsants). Successive measurements of the cerebral arteriovenous oxygen (C (a - v) O2) and glucose (C (a - v)gluc) contents were made. The oxygen glucose index (OGI) was calculated according to Cohen's formula. The first set of measurements were carried out within the first 30 h after CPA. The last measurements were made a few hours before death or recovery, or stabilization of the coma. Patients were assigned to 2 groups according to their neurological outcome: group R (n = 8), patients who recovered consciousness; group D (n = 12), patients who developed brain death or a vegetative state - Safar's cerebral performance category 4. During the first 30 h, there was no relationship between clinical course, EEG and cerebral outcome. Half of the patients died or recovered within 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain death and the persistent vegetative state: similarities and contrasts

Brain death and the persistent vegetative state (PVS) share the following features: 1.) There is death of neurons in the brain; 2.) Both require an etiology which is capable of causing neuronal death. 3.) The potential for cognition is totally and permanently lost; 4.) Intensive medical support is usually withdrawn. In contrast, the diagnosis of brain death depends on death of the brainstem, while PVS implies permanent and total loss of forebrain function. While brainstem death can be diagnosed clinically, accurate prognosis in PVS requires additional investigation. Thus far, the EEG is the most specific test of neuronal function in the cerebral cortex. Brain death is equivalent to death, while PVS is not; management of the latter is more complex because of medical, social, ethical and legal factors.

Natural history of global and critical brain ischaemia. Part I: EEG and neurological signs during the first year after cardiopulmonary resuscitation in patients subsequently regaining consciousness

Of 125 patients who had no detectable cortical activity (DCA) in the electroencephalograph (EEG) immediately upon resuscitation from circulatory arrest of primary cardiovascular aetiology, 37 subsequently regained consciousness; these patients had their EEG and neurological status serially investigated until they expired or had survived one year. The orderly cerebral recovery during postischaemic unconsciousness was characterized by a sequential appearance of EEG configurations and related neurological signs. The absence of DCA was at first accompanied by miosis and all the cranial nerve reflexes except the caloric vestibular reflex (phase of exclusive presence of cranial nerve reflexes) and then by motor responsiveness, predominantly decerebrate posturing (phase of cephalic reactivity). Electrocortical activity appeared thereafter first as a phase described as 'intermittent cortical activity' (ICA) accompanied by medium sized pupils, decorticate posturing and stereotypic reactivity and then as a phase described as 'continuous cortical activity' (CCA) associated with stereotypic reactivity. Consciousness returned 11-720 h later. The EEG and neurological recovery occurred independently after awakening; but elementary motor, sensory and mental faculties were regained in a characteristic sequence. Initially, the alert patient had a phase of 'severe disability' seen as communicating motor responses, eye-orientation and a bilateral Babinski response; in the subsequent phase of 'moderate disability' speech, auto-orientation, locomotor control, and a normal plantar response were then restored; finally in the phase of slight- or no disability allo-orientation, retention and recall reappeared. Thirteen patients made a complete recovery of all faculties 83--2150 h after cardiopulmonary resuscitation.

Natural history of global and critical brain ischaemia. Part III: cerebral prognostic signs after cardiopulmonary resuscitation. Cerebral recovery course and rate during the first year after global and critical ischaemia monitored and predicted by EEG and neurological signs

The monitoring and predictive value of the electroencephalography (EEG) and neurological signs was evaluated in 125 patients who had sustained critical brain ischaemia during circulatory arrest of primary cardiovascular aetiology. Cranial nerve areflexia with mydriasis or extension of the upper limb in response to cutaneous stimulation reliably indicated brain death and appearance of the flexion reflex or of intermittent spikes and sharp waves in the EEG predicted an unfavourable outcome; but other EEG configurations and nuerological signs per se were inaccurate variables to assess the outcome. By contrast, the recovery course and rate were accurately assessed by the time for appearance of cerebral functions; the caloric vestibular reflex, decorticate posturing, stereotypic reactivity, intermittent and continuous electrocortical activity were regained within ultimate time limits of 900, 540, 455, 450, and 1020 min, respectively, corresponding to the longest delay compatible with recovery of function at all, and within critical time limits of 165, 180, 180, 200, and 630 min, respectively, corresponding to the longest delay compatible with recovery of consciousness. Moreover, intermittent electrocortical activity, consciousness, speech and ability to cope with personal necessities were regained within supercritical time limits of 3, 47, 156, and 336 h, respectively, corresponding to the longest delay compatible with complete restoration of post-awakening faculties within 1 year of resuscitation. Prognosis was currently ascertained during the period of unconsciousness as cephalic reactivities, and electrocortical activities were regained in an exponential relationship to time. Bradycardia or asystole prior to resuscitation and metabolic acidosis, hypotensive heart failure, recurrent circulatory arrest and pneumonia thereafter influenced the cerebral recovery adversely.

'alpha pattern coma' following cerebral anoxia

In 30 patients, who were all comatose as a result of cerebral anoxia after cardiac arrest, at least one EEG with activity in the alpha frequency range was recorded. Regionally the activity of the above mentioned characteristic was often diffusely distributed or most pronounced occipitally, whereas a tendency to affect other regions was rarely observed. In 50% of the patients, where more than one EEG was recorded, the 'alpha' rhythm was still present in the following record. Only one of the patients survived, and even so, with considerable mental defects. In 4 patients the level of consciousness improved, but 3 of them never reached a definite level of cortical function and died as a result of cerebral anoxia.

'Alpha-pattern coma' and survival after cardiac arrest

A case of survival despite on EEG in the alpha range during coma after cardiac arrest in connection with acute myocardial infarction is reported. The other 5 published cases are referred to. On the basis of the available literature it is concluded that it is impossible to determine the few patients who will survive despite 'alph-pattern coma'.