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Biomedical subjects

D L McArthur

Publications and source records attributed to D L McArthur.

At least 19 recordsLinked to original sources
PubMed2001

Metabolic recovery following human traumatic brain injury based on FDG-PET: time course and relationship to neurological disability.

OBJECTIVE: Utilizing [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), we assessed the temporal pattern and the correlation of functional and metabolic recovery following human traumatic brain injury. DESIGN AND SUBJECTS: Fifty-four patients with injury severity ranging from mild to severe were studied. Thirteen of these patients underwent both an acute and delayed FDG-PET study. RESULTS: Analysis of the pooled global cerebral metabolic rate of glucose (CMRglc) values revealed that the intermediate metabolic reduction phase begins to resolve approximately one month following injury, regardless of injury severity. The correlation, in the 13 patients studied twice, between the extent of change in neurologic disability, assessed by the Disability Rating Scale (DRS), and the change in CMRglc from the early to late period was modest (r = -0.42). Potential explanations for this rather poor correlation are discussed. A review of the pertinent literature regarding the use of PET and related imaging modalities, including single photon emission tomography (SPECT) for the assessment of patients following traumatic brain injury is given. CONCLUSION: The dynamic profile of CMRglc that changes following traumatic brain injury is seemingly stereotypic across a broad range and severity of injury types. Quantitative FDG-PET cannot be used as a surrogate technique for estimating degree of global functional recovery following traumatic brain injury.

Activities of Daily Living↗
PubMed2001

Patient volume per surgeon does not predict survival in adult level I trauma centers.

BACKGROUND: The 1999 American College of Surgeons resources for optimal care document added the requirement that Level I trauma centers admit over 240 patients with Injury Severity Score (ISS) > 15 per year or that trauma surgeons care for at least 35 patients per year. The purpose of this study was to test the hypothesis that high volume of patients with ISS > 15 per individual trauma surgeon is associated with improved outcome. METHODS: Data were obtained from the trauma registry of the five American College of Surgeons-verified adult Level I trauma centers in our mature trauma system between January 1, 1998, and March 31, 1999. Data abstracted included age, sex, Glasgow Coma Scale (GCS) score, intensive care unit length of stay, hospital length of stay, probability of survival (Ps), mechanism of injury, number of patients per each trauma surgeon and institution, and mortality. Multiple logistic regression was performed to select independent variables for modeling of survival. RESULTS: From the five Level I centers there were 11,932 trauma patients in this time interval; of these, 1,754 patients (14.7%) with ISS > 15 were identified and used for analysis. Patients with ISS > 15 varied from 173 to 625 per institution; trauma surgeons varied from 8 to 25 per institution; per-surgeon patient volume varied from 0.8 to 96 per year. Logistic regression analysis revealed that the best independent predictors of survival were Ps, GCS score, age, mechanism of injury, and institutional volume (p < 0.01). Age and institutional volume correlated negatively with survival. Analysis of per-surgeon patient caseload added no additional predictive value (p = 0.44). CONCLUSION: The significant independent predictors of survival in severely injured trauma patients are Ps, GCS score, age, mechanism of injury, and institutional volume. We found no statistically meaningful contribution to the prediction of survival on the basis of per-surgeon patient volume. Since this volume criterion for surgeon enpanelment and trauma center designation would not be expected to improve outcome, such a requirement should be justified by other measures or abandoned.

Adult↗
PubMed2001

Local television news coverage of traumatic deaths and injuries.

OBJECTIVE: To assess how local television news programs' reporting of injuries and deaths from traumatic causes compares with coroners' records of deaths and the estimated incidence of injuries in the same geographic area during the same time. METHODS: Using epidemiologic methods, we identified the underlying cause of death or injury in each of 828 local television news stories broadcast in Los Angeles during late 1996 or early 1997 that concerned recent (<3 days) traumatic injuries or deaths in Los Angeles County. Odds ratios were computed using deaths by homicide or injuries sustained in assaults as the referent group. RESULTS: The number of persons depicted as dead amounted to 47.8% of the actual total number of traumatic deaths occurring in Los Angeles County during the study period. In contrast, the number depicted as injured represented only 3.4% of injuries due to traumatic causes. Both injuries and deaths due to fires, homicides, and legal interventions were proportionally well represented. However, injuries and deaths from accidental poisoning, falls, and suicide were significantly underrepresented. CONCLUSIONS: Some types of events receive disproportionately more news coverage than others. Local television news tends strongly to present only those events concerned with death or injury that are visually compelling. We discuss reasons for concern about the effect that this form of information bias has on public understanding of health issues and possible counteractions that physicians can take.

Cause of Death↗
PubMed2001

Carbon dioxide reactivity, pressure autoregulation, and metabolic suppression reactivity after head injury: a transcranial Doppler study.

OBJECT: Contemporary management of head-injured patients is based on assumptions about CO2 reactivity, pressure autoregulation (PA), and vascular reactivity to pharmacological metabolic suppression. In this study, serial assessments of vasoreactivity of the middle cerebral artery (MCA) were performed using bilateral transcranial Doppler (TCD) ultrasonography. METHODS: Twenty-eight patients (mean age 33 +/- 13 years, median Glasgow Coma Scale score of 7) underwent a total of 61 testing sessions during postinjury Days 0 to 13. The CO2 reactivity (58 studies in 28 patients), PA (51 studies in 23 patients), and metabolic suppression reactivity (35 studies in 16 patients) were quantified for each cerebral hemisphere by measuring changes in MCA velocity in response to transient hyperventilation, arterial blood pressure elevation, or propofol-induced burst suppression, respectively. One or both hemispheres registered below normal vasoreactivity scores in 40%, 69%, and 97% of study sessions for CO2 reactivity, PA, and metabolic suppression reactivity (p < 0.0001), respectively. Intracranial hypertension, classified as intracranial pressure (ICP) greater than 20 mm Hg at the time of testing, was associated with global impairment of CO2 reactivity, PA, and metabolic suppression reactivity (p < 0.05). A low baseline cerebral perfusion pressure (CPP) was also predictive of impaired CO2 reactivity and PA (p < 0.01). Early postinjury hypotension or hypoxia was also associated with impaired CO2 reactivity (p < 0.05), and hemorrhagic brain lesions in or overlying the MCA territory were predictive of impaired metabolic suppression reactivity (p < 0.01). The 6-month Glasgow Outcome Scale score correlated with the overall degree of impaired vasoreactivity (p < 0.05). CONCLUSIONS: During the first 2 weeks after moderate or severe head injury, CO2 reactivity remains relatively intact, PA is variably impaired, and metabolic suppression reactivity remains severely impaired. Elevated ICP appears to affect all three components of vasoreactivity that were tested, whereas other clinical factors such as CPP, hypotensive and hypoxic insults, and hemorrhagic brain lesions have distinctly different impacts on the state of vasoreactivity. Incorporation of TCD ultrasonography-derived vasoreactivity data may facilitate more injury- and time-specific therapies for head-injured patients.

Adolescent↗
PubMed2000

Injury hospitalizations before and after the 1994 Northridge, California earthquake.

This study compared hospital-admitted injuries during the 14 days after the Northridge, California, earthquake of January 17, 1994, with hospital-admitted injuries during the preceding 16 days at the same facilities. Seventy-eight hospitals providing emergency care in Los Angeles County were screened; 16 were identified as having admitted at least one person for an earthquake-related injury. Retrospective chart reviews of hospitalized injuries for all of January 1994 were conducted at those facilities. The Northridge earthquake resulted in 138 injuries severe enough to require hospitalization. On the day of the earthquake, such injuries were 74% more frequent than usual overall. Some hospitals experienced as many as five times the number of injury admissions seen in the days preceding the event. The increase in caseload was short-lived, however; injury admissions tended to return to normal levels within two days after the quake. Previous reported estimates of the overall number of severe injuries caused by the Northridge earthquake appear to be exaggerated.

California↗
PubMed2000

Dissociation of cerebral glucose metabolism and level of consciousness during the period of metabolic depression following human traumatic brain injury.

Utilizing [18F]fluorodeoxyglucose positron emission tomography (FDG-PET), we studied the correlation between CMRglc and the level of consciousness within the first month following human traumatic brain injury. Forty-three FDG-PET scans obtained on 42 mild to severely head-injured patients were quantitatively analyzed for the determination of regional cerebral metabolic rate of glucose (CMRglc). Reduction of cerebral glucose utilization, defined as a CMRglc of < or =4.9 mg/100 g/min, was present regionally in 88% of the studies. The prevalence of global cortical CMRglc reduction was higher in severely head-injured patients (86% versus 67% mild-moderate), although the absolute magnitude was similar across the injury severity spectrum (mean CMRglc 3.9 +/- 0.6 mg/100 g/min). The level of consciousness, as measured by the Glasgow Coma Scale, correlated poorly with the global cortical CMRglc value (r = 0.08; p = 0.63). With regards to severity of head injury, this correlation was worst for the severely injured (r = -0.11; p = 0.58) and better for the mildly injured patients (r = 0.50; p = 0.07). In most cases, intraparenchymal hemorrhagic lesions were associated with either focal CMRglc reduction or elevation. It is concluded that the etiologies of CMRglc reduction are likely multifactorial given the complex nature of traumatic brain injury and that the reduction of CMRglc represents a fundamental pathobiologic state following head injury that is not tightly coupled to level of consciousness.

Adult↗
PubMed2000

Violence and its injury consequences in American movies: a public health perspective.

OBJECTIVES: To evaluate the seriousness and frequency of violence and the degree of associated injury depicted in the 100 top-grossing American films of 1994. METHODS: Each scene in each film was examined for the presentation of violent actions on persons and coded by a systematic context-sensitive analytic scheme. Specific degrees of violence and indices of injury severity were abstracted. Only actually depicted, not implied, actions were coded, although both explicit and implied consequences were examined. RESULTS: The median number of violent actions per film was 16 (range, 0-110). Intentional violence outnumbered unintentional violence by a factor of 10. Almost 90% of violent actions showed no consequences to the recipient's body, although more than 80% of the violent actions were executed with lethal or moderate force. Fewer than 1% of violent actions were accompanied by injuries that were then medically attended. CONCLUSIONS: Violent force in American films of 1994 was overwhelmingly intentional and in 4 of 5 cases was executed at levels likely to cause significant bodily injury. Not only action films but movies of all genres contained scenes in which the intensity of the action was not matched by correspondingly severe injury consequences. Many American films, regardless of genre, tend to minimize the consequences of violence to human beings.

Humans↗
PubMed1999

The prevalence of non-standard helmet use and head injuries among motorcycle riders.

OBJECTIVES: This study examined the prevalence of non-standard helmet use among motorcycle riders following introduction of a mandatory helmet use law and the prevalence of head injuries among a sample of non-standard helmet users involved in motorcycle crashes. METHODS: Motorcycle rider observations were conducted at 29 statewide locations in the 2 years following the introduction of the mandatory helmet use law in January, 1992. Medical records of motorcyclists who were injured in 1992 for whom a crash report was available and for whom medical care was administered in one of 28 hospitals were reviewed. Chi-squares and analysis of variance were used to describe differences between groups. RESULTS: Prevalence of non-standard helmet use averaged 10.2%, with a range across observation sites from 0 to 48.0%. Non-standard helmet use varied by type of roadway, day of week, and time of day. Injuries to the head were more frequent and of greater severity among those wearing non-standard helmets than both those wearing no helmet and those wearing standard helmets. CONCLUSIONS: Non-standard helmets appear to offer little head protection during a crash. Future study is needed to understand the dynamics leading to head injury when different types of helmets are worn.

Accidents, Traffic↗
PubMed1999

The specific deterrence of administrative per se laws in reducing drunk driving recidivism.

OBJECTIVE: To determine if administrative per se laws are more effective than other forms of sanction against drunk drivers. SEARCH STRATEGIES: The overall goal of the search strategy was to identify all relevant research concerning the specific effects of administrative per se laws in reducing drunk driving recidivism, traffic crashes, and other alcohol-related driving offenses by those drivers with suspended licenses. Known review articles and MEDLINE reviews formed the reference bibliography; numerous databases were searched from 1966 to the present, using such terms as alcohol, driver's license, recidivism, deterrence, and legislation. SELECTION CRITERIA: To be selected the study had to be designed to test the presence of an administrative per se license revocation or restriction in a defined cohort, have a suitable comparison cohort whose sanctions for drunk driving were not administrative per se, and provide relevant data that lead to an objective assessment of recidivism. Types of studies included were randomized controlled trials, nonrandomized controlled trials, other specialized cohort studies, and case-control studies. Three studies were identified; all met inclusion criteria. DATA COLLECTION AND ANALYSIS: One of the studies provided Kaplan-Meier survival curves for failure times defined as days to new conviction following the initial arrest. Odds ratios and 99% confidence intervals were extracted from two of the studies and additional information was supplied by the author of one of the studies. MAIN RESULTS: One study found that one state in the United States experienced a reduction of about one third in repeat arrests for drunk driving over a 3-year period among those who were arrested under administrative per se, relative to recidivism seen in a comparison cohort of drivers prior to administrative per se. Two other states did not experience any change in recidivism. The second study found that drivers whose licenses were suspended under administrative per se were 39% less likely during the first year following suspension to be rearrested on the charge of driving while intoxicated compared with a comparison cohort. This differential persisted into the second year of follow-up, but disappeared by the third year. The third study found both first offenders and repeat offenders arrested under administrative per se were 34% less likely to be involved during the year following their arrest in a subsequent motor vehicle crash compared with those in the comparison cohort. Drivers with administrative per se suspensions were 21% less likely to be involved in additional drunk driving offenses, and 27% less likely to be involved in reckless driving offenses related to alcohol. CONCLUSIONS: Administrative per se laws governing license restriction for drivers have been shown to be effective in some states but not others in decreasing the rates at which these same drivers are subsequently involved in a motor vehicle crash or in another alcohol-related offense, compared with drivers who were sanctioned through other conventional judicial processes. Replications are needed in other states or large driver populations using improved methodology.

Alcohol Drinking↗
PubMed1999

Multiple organ failure: by the time you predict it, it's already there.

OBJECTIVE: Validate an at-risk population to study multiple organ failure and to determine the importance of organ dysfunction 24 hours after injury in determining the ultimate severity of multiple organ failure. METHODS: We evaluated 105 patients admitted to five academic trauma centers during a 1-year period who survived for more than 24 hours with Injury Severity Scores > or = 25 and who received 6 or more units of blood. Organ dysfunction was scored daily with a modified multiple organ failure scoring system made up of individual adult respiratory distress syndrome score, renal dysfunction, hepatic dysfunction, and cardiac dysfunction scores. Multiple organ failure (MOF) severity was quantitated using the maximum daily multiple organ failure score and the cumulative sum of daily multiple organ failure scores for the first 7 days (MOF 7) and 10 days (MOF 10). Independent variables included markers of tissue injury, shock, host factors, physiologic response, therapeutic factors, and organ dysfunction within the first 24 hours after admission. Data were subjected to a conditional stepwise multiple regression analysis, first excluding and then including 24-hour MOF as an independent variable. RESULTS: Of the 105 high-risk patients, 69 (66%) developed a maximum daily multiple organ failure score > or = 1; 50 (72%) did so on day 1 one and 60 (87%) did so by day 2. In multiple regression models, the multiple correlation coefficient increased from 0.537 to 0.720 when maximum MOF was the dependent variable, from 0.449 to 0.719 when maximum daily MOF was the dependent variable, from 0.519 to 0.812 when MOF 7 was the dependent variable, and from 0.514 to 0.759 when MOF 10 was the dependent variable. CONCLUSION: We have confirmed that the population of patients with Injury Severity Scores > or = 25 who received 6 or more units of blood represent a high-risk group for the development of multiple organ failure. Our data also indicate that multiple organ failure after trauma is established within 24 hours of injury in the majority of patients who develop it. It appears that multiple organ failure is already present at the time when most published models are trying to predict whether or not it will occur.

Adult↗
PubMed1997

Epidemiology of acute low back injury in employees of a large home improvement retail company.

Acute low back injuries are described in a cohort of about 31,000 material handlers employed in all Home Depot, Inc., retail stores in California from 1990 through 1994. With over 87 million work hours, incidence density rates, rate ratios, and confidence intervals are given by age, sex, length of employment, and job-lifting requirements. Injuries are further described by lost work days, activity at time of injury, work restrictions, and time frames. The unadjusted low back injury rate per million work hours was 1.6 times higher for men compared with women, and rates were highest for those less than 25 years of age, those with less than 2 years of current job experience, and employees with the greatest materials lifting and handling job requirements. These findings in unadjusted rates and rate ratios persisted when each was adjusted through a Poisson regression model, with the exception of sex. The adjusted risk ratio for males was reversed with significantly higher risk in females when the rate ratio was adjusted for age, lifting intensity, and length of job experience. Injuries were most commonly associated with lifting activities and, while injury occurrence was highest from 10 a.m. to 4 p.m., rates were greatest during those hours when the store was closed to retail activities. Merchandise stocking that requires heavy and frequent materials handling is done during these hours. Fewer injuries than expected were reported on weekends, days with considerably less materials handling activities.

Absenteeism↗
PubMed1997

Determining injury at work on the California death certificate.

OBJECTIVES: This study examined decisions of California Country Coroner's offices in determining injury at work and identified factors influencing this decision. METHODS: Surveys were sent to California County Coroner's offices (response rate = 93%). The survey included 23 vignettes that required the respondent to determine whether the fatality involved an injury at work. The Rasch method was used to determine internal consistency in endorsing vignettes and to determine overall endorsability of vignettes based on underlying factors. RESULTS: Respondents showed internal consistency but much disagreement in their endorsement of vignettes. Decedents who were performing paid work or were on their work site during working hours were almost unanimously endorsed as having incurred an injury at work. Non-payment, travel/transportation, suicide, and nontraditional work sites and work hours led to disagreement and uncertainty among respondents. CONCLUSIONS: Coroners have different methods of determining injury at work on the death certificate, and available guidelines do not define many of the ambiguous situations encountered by coroners.

Accidents, Occupational↗
PubMed1997

Cerebral hyperglycolysis following severe traumatic brain injury in humans: a positron emission tomography study.

Experimental traumatic brain injury studies have shown that cerebral hyperglycolysis is a pathophysiological response to injury-induced ionic and neurochemical cascades. This finding has important implications regarding cellular viability, vulnerability to secondary insults, and the functional capability of affected regions. Prior to this study, posttraumatic hyperglycolysis had not been detected in humans. The characteristics and incidence of cerebral hyperglycolysis were determined in 28 severely head injured patients using [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET). The local cerebral metabolic rate of glucose (CMRG) was calculated using a standard compartmental model. In six of the 28 patients, the global cerebral metabolic rate of oxygen (CMRO2) was determined by the simultaneous measurements of arteriovenous differences of oxygen and cerebral blood flow (xenon-133). Hyperglycolysis, defined as an increase in glucose utilization that measures two standard deviations above expected levels, was documented in all six patients in whom both FDG-PET and CMRO2 determinations were made within 8 days of injury. Five additional patients were found to have localized areas of hyperglycolysis adjacent to focal mass lesions. Within the 1st week following the injury, 56% of patients studied had presumptive evidence of hyperglycolysis. The results of this study indicate that the metabolic state of the traumatically injured brain should be defined differentially in terms of glucose and oxygen metabolism. The use of FDG-PET demonstrates that hyperglycolysis occurs both regionally and globally following severe head injury in humans. The results of this clinical study directly complement those previously reported in experimental brain-injury studies, indicating the capability of imaging a fundamental component of cellular pathophysiology characteristic of head injury.

Adolescent↗
PubMed1997

Hemodynamically significant cerebral vasospasm and outcome after head injury: a prospective study.

The authors prospectively investigated cerebral hemodynamic changes in 152 patients with head injuries to clarify the relationship between cerebral vasospasm and outcome. They also sought to determine the most clinically meaningful criteria for diagnosing cerebral vasospasm. Patients with varying degrees of moderate-to-severe head injury were monitored using transcranial Doppler (TCD) ultrasonography and intravenous 133Xe-cerebral blood flow (CBF) measurements. Outcome was determined at 6 months. Using TCD ultrasonography, mean flow velocities were determined for the middle cerebral artery (V(MCA), 149 patients) and basilar artery (V(BA), 126 patients). Recordings of the mean extracranial internal carotid artery velocity (V(EC-ICA)) were also performed to determine the hemispheric ratio (V(MCA)/V(EC-ICA), 147 patients). Cerebral blood flow measurements were obtained in 91 patients. Concurrent TCD and CBF data from 85 patients were used to calculate a "spasm index" (the V(MCA) or V(BA), respectively, divided by the hemispheric or global CBF). The authors investigated the clinical significance of elevated flow velocity, hemispheric ratio, and spasm index. Patients diagnosed as having MCA or BA vasospasm on the basis of TCD-derived criteria alone had a significantly worse outcome than patients without vasospasm. When CBF was considered, hemodynamically significant vasospasm, as defined by an elevated spasm index, was even more strongly associated with poor outcome. Stepwise logistic regression analysis confirmed that hemodynamically significant vasospasm was a significant predictor of poor outcome, independent of the effects of admission Glasgow Coma Scale score and age. On the basis of the results of this study, the authors suggest that the important factor impacting on outcome is not vasospasm per se, but hemodynamically significant vasospasm with low CBF. These findings show that vasospasm is a pathophysiologically important posttraumatic secondary insult, which is best diagnosed by the combined use of TCD and CBF measurements.

Adult↗
PubMed1996

Epidemiologic aspects of brain injury.

Approximately 2 million head injuries occur each year in the United States, producing a brain injury rate of 175 to 200 per 100,000 population and causing as many as 56,000 deaths per year. The economic and emotional toll of this public health burden is staggering. By identifying risk factors, perhaps effective legislation and environmental and educational intervention strategies can be developed to prevent brain injury.

Accidents, Traffic↗
PubMed1996

Child pedestrian and bicyclist injuries: results of community surveillance and a case-control study.

OBJECTIVES: To describe the dimensions of childhood pedestrian and bicyclist injuries in Long Beach, California, and to identify risk factors for these injuries. POPULATION: Long Beach residents aged 0-14 years who were involved in an auto versus pedestrian or bicyclist incident that resulted in a hospital visit and/or police response, between 1 September 1988 and 31 August 1990. METHODS: Cases were identified retrospectively using hospital charts, police records, and coroner's reports; demographic, clinical, and situational information were abstracted from the same. A nested case-control study was conducted to examine the street environments where children were injured, and to identify environmental risk factors at these case sites. RESULTS: 288 children comprised the sample population. Midblock dart-outs emerged as the single most common type of incident. Most incidents happened on residential streets, but the risk of injury was greatest on larger boulevards, and tended to cluster by region within the city. Adjusted odds ratios show that case sites had a larger proportion of traffic exceeding posted speed limits, and were also four times more likely to be near a convenience store, gas station, or fast food store than control sites. CONCLUSIONS: The findings of this study suggest three possible routes for the prevention of childhood pedestrian and bicyclist injuries: education, law enforcement, and environmental modification.

Accidents, Traffic↗
PubMed1996

Hyperemia following traumatic brain injury: relationship to intracranial hypertension and outcome.

The role of posttraumatic hyperemia in the development of raised intracranial pressure (ICP) has important pathophysiological and therapeutic implications. To determine the relationship between hyperemia (cerebral blood flow (CBF) > 55 ml/100 g/minute), intracranial hypertension (ICP > 20 mm Hg), and neurological outcome, 193 simultaneous measurements of ICP and CBF (xenon-133 method) were obtained in 59 patients with moderate and severe head injury. Hyperemia was associated with an increased incidence of simultaneous intracranial hypertension compared to nonhyperemic CBF measurements (32.2% vs. 21.6%, respectively; p < 0.059). However, in 78% of blood flow studies in which ICP was greater than 20 mm Hg, CBF was less than or equal to 55 ml/100 g/minute. At least one episode of hyperemia was documented in 34% of patients, all of whom had a Glasgow Coma Scale (GCS) score of 9 or below. In 12 individuals with hyperemia without simultaneous intracranial hypertension, ICP was greater than 20 mm Hg for an average of 11 +/- 16 hours and favorable outcomes were seen in 75% of patients. In contrast, in eight individuals with hyperemia and at least one episode of hyperemia-associated intracranial hypertension, ICP was greater than 20 mm Hg for an average of 148 +/- 84 hours (p < 0.001), and a favorable outcome was seen in only one patient (p < 0.001). Compared to the remainder of the cohort, patients with hyperemia-associated intracranial hypertension were distinctive in being the youngest, exhibiting the lowest GCS scores (all < or = 6), and having the highest incidence of effaced basilar cisterns and intractable intracranial hypertension. In the majority of individuals with hyperemia-associated intracranial hypertension, their clinical profile suggests the occurrence of a severe initial insult with resultant gross impairment of metabolic vasoreactivity and pressure autoregulation. In a minority of these patients, however, high CBF may be coupled to a hypermetabolic state, given their responsiveness to metabolic suppressive therapy. In patients with hyperemia but without intracranial hypertension, elevated CBF is also likely to be a manifestation of appropriate coupling to increased metabolic demand consistent with a generally favorable outcome. This study supports the concept that there are multiple etiologies of both elevated blood flow and intracranial hypertension after head injury.

Adult↗