[Unconsciousness and clouded awareness]

Stupor and coma are clinical states in which patients have impaired responsiveness or are unresponsive to external stimulation and are either difficult to arouse or are unarousable. The term stupor refer to states between alertness and coma. An alteration in arousal represents an acute life-threatening emergency, requiring prompt intervention for preservation of life and brain function.

Validation of the Italian version of a new coma scale: the FOUR score

The Glasgow Coma Scale (GCS) is the most widely accepted tool for the evaluation of consciousness, despite several reported shortcomings. A new coma scale, named Full Outline of UnResponsiveness (FOUR) score, is now available. The aim of the present study is to provide and validate the Italian version of the FOUR score. The Italian version of the FOUR score was developed according to a standardized protocol, and thereafter validated in a series of patients with acute neurological illness. For each patient, the FOUR and the GCS scores were recorded by two physicians randomly selected. The inter-rater agreement for the FOUR and the GCS scores was evaluated using the weighted kappa (κ(w)). The receiving operating characteristic curve was also calculated to determine the ability of the scales to predict outcome. Eighty-seven consecutive patients with an acute brain injury were enrolled. The inter-rater agreement was excellent both for the FOUR (κ(w) = 0.953; P < 0.0001) and the GCS (κ(w) = 0.943; P < 0.01). The area under the curve for mortality was 0.935 for the FOUR and 0.953 for the GCS. The FOUR score provides greater neurological details than the GCS. Our data indicate that the Italian version of the FOUR score is a valid predictor of outcome, yielding reproducible findings across raters independent of their expertise.

Neuroethics, neuroimaging, and disorders of consciousness: promise or peril?

The advent of powerful neuroimaging tools such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) has begun to redefine how we diagnose, define, and understand disorders of consciousness such as the vegetative and minimally conscious states. In my paper, I review how research using these methods is both elucidating these brain states and creating diagnostic dilemmas related to their classification as the specificity and sensitivity of traditional behavior-based assessments are weighed against sensitive but not yet fully validated neuroimaging data. I also consider how these methods are being studied as potential communication vectors for therapeutic use in subjects who heretofore have been thought to be unresponsive or minimally conscious. I conclude by considering the ethical challenges posed by novel diagnostic and therapeutic neuroimaging applications and contextualize these scientific developments against the broader needs of patients and families touched by severe brain injury.

Biomechanical correlates of mild diffuse brain injury in the rat

The relationship between diffuse brain injury (DBI) occurrence and impact biomechanics is well documented. Previous studies attempted to develop injury thresholds based on various biomechanical parameters and have demonstrated inconsistent results. The spectral nature of DBI requires robust metrics capable of predicting injury occurrence and severity. In the present study impact biomechanics reported previously were correlated to rat unconsciousness time. Significant correlation was identified in three parameters including square angular velocity, change in rotational velocity, and Head Impact Power. Results suggest rotational loading of the rat head has similar correlates to the human condition. In addition, certain biomechanical parameters demonstrate capacity for predicting DBI severity.

Méthodes d’étude clinique des traumatismes crâniens

The development of data processing techniques has enabled the establishment of large databanks on brain injury. Clinical features are described with clinical scoring scales, the main one being the Glasgow Coma Scale. Three types of patient response are analyzed: eye opening, oral answers, active muscular reaction. The advantages and disadvantages of each are presented. Others scales have been proposed but are not in common use. Several classifications have been established combining depth and length of coma. Post-traumatic amnesia, i.e. the period of time running from the injury to recovery of anterograde memory, constitutes the most important parameter in the classification of these injuries. Generally, three gravity grades are used: mild, moderate and severe brain injuries. Knowledge of the prognosis is essential for determining the most appropriate medical care and is directly related to the quality of the collected data. Five outcome categories can be described.

The predictive value of field versus arrival Glasgow Coma Scale score and TRISS calculations in moderate-to-severe traumatic brain injury

BACKGROUND

Glasgow Coma Scale (GCS) scores are widely used to quantify level of consciousness in the prehospital environment. The predictive value of field versus arrival GCS is not well defined but has tremendous implications with regard to triage and therapeutic decisions as well as the use of various predictive scoring systems, such as Trauma Score and Injury Severity Score (TRISS). This study explores the predictive value of field GCS (fGCS) and arrival GCS (aGCS) as well as TRISS calculations using field (fTRISS) and arrival (aTRISS) data in patients with moderate-to-severe traumatic brain injury (TBI).

METHODS

Major trauma victims with head Abbreviated Injury Scores of 3 or greater were identified from our county trauma registry over a 16-year period. The predictive ability of fGCS with regard to aGCS was explored using univariate statistics and linear regression modeling. The difference between aGCS and fGCS was also modeled against mortality and the composite endpoint using logistic regression, adjusting for fGCS. The predictive value of preadmission GCS (pGCS), defined as either fGCS or aGCS in nonintubated patients without a documented fGCS, with regard to mortality and a composite endpoint representing the need for neurosurgical care (death, craniotomy, invasive intracranial pressure monitoring, or intensive care unit care >48 hours) was determined using receiver-operator curve (ROC) analysis. Finally, fTRISS and aTRISS predicted survival values were compared with each other and to observed survival.

RESULTS

A total of 12,882 patients were included. Mean values for fGCS and aGCS were similar (11.4 and 11.5, respectively, p = 0.336), and a strong correlation (r = 0.67, 95% CI 0.66-0.69, p < 0.0001) was observed between them. The difference between fGCS and aGCS was also predictive of outcome after adjusting for fGCS. Good predictive ability was observed for pGCS with regard to both mortality and neurosurgical intervention. Both fTRISS and aTRISS predicted survival values were nearly identical to observed survival. Observed and fTRISS predicted survival were nearly identical in patients undergoing prehospital intubation

CONCLUSIONS

Values for fGCS are highly predictive of aGCS, and both are associated with outcome from TBI. A change in GCS from the field to arrival is highly predictive of outcome. The use of field data for TRISS calculations appears to be a valid methodological approach, even in severely injured TBI patients undergoing prehospital intubation.

A case of nasomyiasis whose agent was Sarcophaga sp

Sixteen larvae fell from the nose of a 16-year-old girl, who had been hospitalized in the anesthesia intensive care unit for 4 days because of a traffic accident and had been evaluated as E1M2V1 according to Glaskow Coma Scale. These larvae were examined macroscopically and microscopically and it was determined that they were second stage Sarcophage spp. larvae. There was no lesion in the nose of the patient.

The need for head computed tomography in patients sustaining loss of consciousness after mild head injury

BACKGROUND

Many management schemes have incorporated mandatory head computed tomography (HCT) to evaluate a patient sustaining blunt head trauma with a history of loss of consciousness (LOC). Commonly, this is despite physical examination findings warranting such a workup. This study is intended to better identify the significance of selective criteria, a set of constitutional signs and symptoms (CSS) for head injury, to screen patients sustaining blunt head trauma and LOC.

METHODS

Over a 141/2-month period, data were prospectively collected on adults with a history of LOC and a Glasgow Coma Scale score of 14 to 15. Patients were screened for the presence of 10 typical CSS for head injury at admission before undergoing computed tomography of the head. Data collected also included mechanism of injury and alcohol intoxication.

RESULTS

Three hundred thirty-one patients met criteria, of which 195 showed no CSS for head injury. Eleven (5.6%) of these patients were found to have HCT evidence of intracranial injury but resulted in no acute medical intervention. One hundred thirty-six patients had CSS, of which 29 (21.3%) had HCT evidence of injury and resulted in a lengthier hospital stay.

CONCLUSION

The liberal use of HCT in patients without CSS for head injury did not influence patient care, with no increase in morbidity or mortality. These results suggest that LOC alone is not predictive of significant head injury and is not an absolute indications for HCT. More objective criteria, such as CSS, should be used before initiating a costly workup where further diagnostic and therapeutic intervention is unlikely after mild head injury.

Unconsciousness indication using time-domain parameters extracted from mid-latency auditory evoked potentials

OBJECTIVE

The mid-latency auditory evoked potential (MLAEP) has been used to indicate depth of anaesthesia, and is usually analysed in time-domain. This work compares three techniques: Wave Deformation Parameters (PDO), Auditory Evoked Potential Index (AEPidx) and an automatic Nb-wave latency estimator (Nb), in the assessment of unconsciousness onset based on EEG under auditory stimulation.

METHODS

Ten normal adult volunteers, under no pre-anaesthetic drug administration, received propofol during two successive periods of 45 min each one (3 mg/Kg/h and 9 mg/Kg/h), being the EEG collected from 10 min previous to infusion beginning until the subjects woke up. From the time-evolution of MLAEP (averaging of successive sets of 1000 epochs) all the parameters were compared to thresholds (unconsciousness onset indication time) and the results were compared to the instant of pressing interruption of a soft-touch switch, when one assumed the volunteer became unconscious.

RESULTS

The Wilcoxon Signed-Rank test points equivalence between each of the parameters and the switch for, say, alpha = 5%. Bland-Altman diagrams revealed that the Attenuation-PDO has better agreement to the switch than Nb and AEPidx.

CONCLUSION

The results suggest that, at least to indicate unconsciousness, the most reliable effect of the anaesthetic drug on MLAEP would be the amplitude attenuation. Despite the high dependence on noise due to its time-domain basis, the Attenuation-PDO seems to be adequate to assess depth of anaesthesia.

Video analysis of acute motor and convulsive manifestations in sport-related concussion

OBJECTIVES

To describe the motor and convulsive manifestations in acute sports-related head injury.

METHODS

A total of 234 cases of concussive injuries during the 1995 through 1997 football seasons were obtained from the Australian Football League Medical Officers Association injury survey. Of these, 102 cases were recorded adequately on television videotape and were analyzed by two independent observers using a standardized recording form detailing injury mechanics and clinical features of the episodes. Motor and convulsive features were correlated with mechanical variables and with duration of loss of consciousness using linear modeling techniques.

RESULTS

Tonic posturing occurred in 25 subjects, clonic movements in 6, righting movement in 40, and gait unsteadiness in 42. In one subject the tonic and clonic features were sufficiently prolonged to be deemed a concussive convulsion. The only risk factor for tonic posturing using logistic regression was the presence of loss of consciousness (p = 0.0001). There was a trend toward facial impact being an independent predictor of tonic posturing but this did not reach significance. No other independent variable predicted the development of clonic movements, righting movements, or gait unsteadiness.

CONCLUSIONS

Subtle motor manifestations such as tonic posturing and clonic movements commonly occur in concussion; the main predictive factor for tonic posturing is the presence of loss of consciousness. The authors speculate that these clinical features are due to brainstem dysfunction secondary to biomechanical forces inducing a transient functional decerebration.

Near-drowning and drowning classification: a proposal to stratify mortality based on the analysis of 1,831 cases

STUDY OBJECTIVE

To establish an updated classification for near-drowning and drowning (ND/D) according to severity, based on mortality rate of the subgroups.

MATERIALS AND METHODS

We reviewed 41,279 cases of predominantly sea water rescues from the coastal area of Rio de Janeiro City, Brazil, from 1972 to 1991. Of this total, 2,304 cases (5.5%) were referred to the Near-Drowning Recuperation Center, and this group was used as the study database. At the accident site, the following clinical parameters were recorded: presence of breathing, arterial pulse, pulmonary auscultation, and arterial BP. Cases lacking records of clinical parameters were not studied. The ND/D were classified in six subgroups: grade 1--normal pulmonary auscultation with coughing; grade 2--abnormal pulmonary auscultation with rales in some pulmonary fields; grade 3--pulmonary auscultation of acute pulmonary edema without arterial hypotension; grade 4--pulmonary auscultation of acute pulmonary edema with arterial hypotension; grade 5--isolated respiratory arrest; and grade 6--cardiopulmonary arrest.

RESULTS

From 2,304 cases in the database, 1,831 cases presented all clinical parameters recorded and were selected for classification. From these 1,831 cases, 1,189 (65%) were classified as grade 1 (mortality=0%); 338 (18.4%) as grade 2 (mortality=0.6%); 58 (3.2%) as grade 3 (mortality=5.2%); 36 (2%) as grade 4 (mortality=19.4%); 25 (1.4%) as grade 5 (mortality=44%); and 185 (10%) as grade 6 (mortality=93%) (p<0.000001).

CONCLUSION

The study revealed that it is possible to establish six subgroups based on mortality rate by applying clinical criteria obtained from first-aid observations. These subgroups constitute the basis of a new classification.

Ethanol-related visits by adolescents to a pediatric emergency department

The objectives of this study were to determine if the presence of ethanol (ETOH) in patients 10 to 20 years of age is associated with injury and if the patient's mental status reliably predicts their blood ethanol concentration. The study was designed as a retrospective, case-controlled report from a children's hospital emergency department. The data are from 45 patients 10 to 20 years old in whom ETOH was detected on toxic screen and 37 patients (N-ETOH) 10 to 20 years old in whom a toxic screen did not reveal ETOH. Injury occurred in 51% of the ETOH group and 8% (P = 0.0001) of the N-ETOH group. A correlation between blood ETOH level and mental status was found only at the extremes of blood ETOH levels. We conclude that the presence of ETOH may predispose adolescents to injury, requiring treatment in an emergency department. Except at the extremes of ETOH levels, mental status does not predict blood levels. A prospective assessment of mental status and blood ETOH levels in adolescents is needed before mental status assessment can replace the determination of blood ETOH concentrations.

[Examination and observation of the unconscious patient]

The old neurological art of careful examination and detailed description of an unconscious patient delivers a vivid picture of cerebral functions and deficiencies. Daily medical practice, however, demands immediate information with measurable and easily comparable numerical values. This requirement is best satisfied by the current proven and universally accepted 'Glasgow Coma Scale'. Dispensing with the terms: somnolent, soporous and comatose, the GCS numerically marks the depth of the disturbances of consciousness, which, recorded in a graph, indicate the fluctuations of consciousness. The registration of the depth and duration of clouded consciousness is a decisive criterion for the prognosis.

[Classification and definition of consciousness disorders]

A classification of the disturbances of consciousness is given, and the possible causes are listed. The criteria used in Switzerland for the diagnosis of brain death are presented in detail.

Classification of coma

By order of the Head Injuries Committee of the W.F.N.S. the author and his coworkers give definitions of consciousness, clouding of consciouness and unconciousness or coma. Furthermore, they suggest a definition of the termination of unconsciousness, with particular reference to the transition into a stage of clouding of consciousness. Any statistical evaluation and comparison of different materials depend on the use of identical definitions. As an example, it has been shown that the duration of aa uninterrupted coma, which can be survived, becomes relatively short if in accordance with the proposed definitions the various stages of clouding of consciousness are excluded from "coma".

[Absences and absence-like crises]

Under the same clinical picture the "absence" may group various forms of epileptic and non-epileptic disease entities, each having a different pathogenesis and a different EEG correlate. The investigative procedures, therapy and prognosis are likewise non-uniform. This suggests the need for a nomenclatorial division for these different nosological units and their classification into typical and atypical absences, absence-like partial (focal) fits, and paroxysmal nonepileptic disturbances of consciousness.