Harbingers of poor outcome the day after severe brain injury: hypothermia,hypoxia, and hypoperfusion

BACKGROUND: Traumatic brain injury (TBI) can be compounded by physiologic derangements that produce secondary brain injury. The purpose of this study is to elucidate the frequency with which physiologic factors that are associated with secondary brain injury occur in patients with severe closed head injuries and to determine the impact of these factors on outcome. METHODS: The records of 81 adult blunt trauma patients with Glasgow Coma Scale scores < or = 8 and transport times < 2 hours to a Level I trauma center were retrospectively reviewed searching for the following 11 secondary brain injury factors (SBIFs) in the first 24 hours postinjury: hypotension, hypoxia, hypercapnia, hypocapnia, hypothermia, hyperthermia, metabolic acidosis, seizures, coagulopathy, hyperglycemia, and intracranial hypertension. We recorded the worst SBIF during six time periods: hours 1, 2, 3, 4, 5 to 14, and 16 to 24. Occurrence of each SBIF was then correlated with outcome. RESULTS: Hypocapnia, hypotension, and acidosis occurred more frequently than other SBIFs (60-80%). Hypotension, hyperglycemia, and hypothermia were associated with increased mortality rate. Patients with episodes of hypocapnia, acidosis, and hypoxia had significantly longer intensive care unit length of stay (LOS). These three SBIFs and hyperglycemia related to longer hospital LOS as well. Hypotension and acidosis were associated with discharge to a rehabilitation facility rather than home. Finally, multivariate regression analysis revealed that hypotension, hypothermia, and Abbreviated Injury Scale score of the head were independently related to mortality, whereas other SBIFs, age, Injury Severity Score, and Glasgow Coma Scale score were not. Metabolic acidosis and hypoxia were related to longer intensive care unit and hospital LOS. CONCLUSION: Our early management of head-injured patients stresses avoidance and correction of SBIFs at all costs. Nonetheless, SBIFs occur frequently in the first 24 hours after traumatic brain injury. Six of the 11 factors studied are associated with significantly worse outcomes. Hypotension and hypothermia are independently related to mortality. Because these SBIFs are potentially preventable, protocols could be developed to decrease their frequency.     

Prehospital hypoxia affects outcome in patients with traumatic brain injury: a prospective multicenter study

BACKGROUND: The goals of this study were to determine the incidence and duration of hypotension and hypoxia in the prehospital setting in patients with potentially survivable brain injuries, and to prospectively examine the association of these secondary insults with mortality and disability at hospital discharge. METHODS: Trauma patients with suspected brain injuries underwent continuous blood pressure and pulse oximetry monitoring during helicopter transport. Postadmission inclusion criteria were (1) diagnosis of acute traumatic brain injury (TBI) confirmed by computed tomography (CT) scan, operative findings, or autopsy findings; and (2) Head Abbreviated Injury Scale (AIS) score of > or = 3 or Glasgow Coma Scale (GCS) score of < or = 12 within the first 24 hours of admission. Patients were excluded with (1) no abnormal intracranial findings on the patient's CT scan; (2) determination of a nonsurvivable injury (based on an AIS score of 6 for any body region; or, (3) death in less than 12 hours after injury. Primary outcome measures included mortality and Disability Rating Scale score at discharge. RESULTS: We enrolled 150 patients into the study. Fifty-seven patients had at least one secondary insult; 37 had only hypoxic episodes, 14 had only hypotensive episodes, and 6 patients had both. Demographics and injury characteristics did not differ between those with and those without secondary insults. The mortality for patients without secondary insults was 20%, compared with 37% for patients with hypoxic episodes, 8% for patients with hypotensive episodes, and 24% for patients with both. The Disability Rating Scale score at discharge was significantly higher in patients with secondary insults. Using multivariate analysis, the calculated odds ratio of mortality caused by prehospital hypoxia after head injury was 2.66 (p < 0.05). CONCLUSIONS: Secondary insults after TBI are common, and these insults are associated with disability. Hypoxia in the prehospital setting significantly increases the odds of mortality after brain injury controlled for multiple variables.     

Outcome prediction in early management of severe head injury: an experience in Malaysia.

The outcome of 109 patients with severe head injury was studied in relation to clinical and computed tomographic (CT) criteria on admission, after resuscitation. Age, Glasgow Coma Score (GCS) and state of pupils strongly correlated with outcome. The presence of hypothalamic disturbances, hypoxia and hypotension were associated with an adverse outcome. The CT indicators associated with poor outcome were perimesencephalic cistern (PMC) obliteration, subarachnoid haemorrhage, diffuse axonal injury and acute subdural haematoma. The prognostic value of midline shift and mass effect were influenced by concomitant presence of diffuse brain injury. For the subset of patients aged < 20 years, with GCS 6-8 and patent PMC (n = 21), 71.4% correct predictions were made for a good outcome. For the subset of patients aged > 20 years, with GCS 3-5 and partial or complete obliteration of PMC (n = 28), 89.3% correct predictions were made for a poor outcome.     

Time of hypotension and discharge outcome in children with severe traumatic brain injury

We performed a retrospective study at a level I pediatric trauma center of patients admitted between 1998 and 2005 to determine the time after severe pediatric traumatic brain injury (TBI) that hypotension (systolic blood pressure [SBP] of <5th percentile) is most strongly associated with poor outcome. One hundred forty-six patients of <18 years of age with TBI, head Abbreviated Injury Score (AIS) of >or=3, and PICU admission Glasgow Coma Scale (GCS) score of <9 formed the analytic sample. Available SBP readings through the first 72 h after severe TBI were collected. SBP of <5th percentile was defined as hypotension. Discharge Glasgow Outcome Scale (GOS) score of <4 defined poor outcome. Of 146, 59 (40%) patients had discharge GOS of <4 and 12% died. The adjusted risk of poor outcome associated with hypotension stabilized by 8 h (adjusted risk ratio [RR] 1.7; 95% confidence interval [CI] 1.1-2.6) after injury. The risk of poor outcome peaked with hypotension occurring within the first 6 h after injury (RR 2.0, 95% CI 1.3-3.3). Poor discharge GOS was predicted by hypotension occurring during the first 6 h after injury. SBP data beyond the first 6 h did not improve our ability to predict poor discharge GOS. The first 6 h after severe pediatric TBI may represent a critical time period for either predicting or improving outcome.     

Early prognosis in severe cranio-cerebral trauma using the Glasgow Coma Score and evoked potentials

During 72 h following severe head injury, 103 patients in acute posttraumatic coma were assessed by clinical examinations (documented by Glasgow Coma Score) and brain stem auditory evoked potentials (BAEP) as well as short-latency somatosensory evoked potentials (SEP) following median-nerve stimulation. Patient outcomes were classified at 6 months or more according to the following categories: good recovery, severely disabled or vegetative, and brain dead. Patients who had died of systemic complications (pneumonia, septicemia, renal failure, etc.) were excluded from the study. The Glasgow Coma Score was reliable in forecasting a favorable outcome; all patients with a Score over 9 points had a good recovery. The Glasgow Coma Score was not reliable in predicting an unfavorable outcome, however; some patients with the lowest possible Glasgow Coma Score (3 points) at the early clinical examination survived with good recovery. The BAEPs were reliable predictors of an unfavorable outcome; the outcome was unfavorable when a missing wave V or more missing waves pointed toward a secondary brainstem lesion. Normal BAEPs were not reliable, however, in predicting a favorable outcome. SEP data served as a prognostic indicator of unfavorable as well as favorable outcomes. In summary, evoked potentials add valuable information to the clinical examination in assessing a patient's outcome after severe head injury.     

Effects of antiplatelet agents on outcomes for elderly patients with traumatic intracranial hemorrhage

BACKGROUND: Recent literature on elderly patients with traumatic intracranial hemorrhage receiving preinjury antiplatelet agents shows a mortality rate of 47%. METHODS: In a retrospective analysis, patients older than 50 years presenting to the hospital over the past 4 years with traumatic intracranial hemorrhage and the use of aspirin, clopidogrel, or a combination were compared with a control group that had hemorrhage but no antiplatelet medications. Patient demographics, mechanism of injury, and injury scores were recorded. RESULTS: No significant differences were found between the 90 study patients and the 89 control subjects in terms of demographics, mechanism of injury, Injury Severity Score, Glasgow Coma Score, or hospital length of stay. Patients receiving antiplatelet therapy had significantly more comorbid conditions (71% vs. 35%; p < 0.001). In this series, 21 study patients and 8 control patients died (23% vs. 8.9%; p = 0.016). Age older than 76 years and a Glasgow Coma Score lower than 12 were correlated significantly with increased mortality. CONCLUSIONS: The use of antiplatelet agents with elderly trauma patients significantly increases the risk of mortality when head injury involves intracranial hemorrhage.     

Serum S-100B protein and neuron-specific enolase after traumatic brain injury

OBJECTIVE: The aim of this study was to investigate S-100B protein and NSE as a serum marker of brain cell damage after traumatic brain injury. MATERIAL AND METHODS: Forty-one patients with traumatic brain injury were included in this prospective study. Venous blood samples for S-100B protein and NSE were taken after admission and on the next day. Serum levels of S-100 protein and NSE were compared with Glasgow Coma Scale score, computed tomographic findings and outcome after 3 months. RESULTS: Serum S-100B protein and NSE were significantly correlated with Glasgow Coma Scale score and outcome after 3 months. The significant correlation was found between the initial S-100B and NSE (P < 0.001). In patients without parenchymal injuries on computed tomographic scan such as epidural hematoma and concussion, the elevation of S-100B protein and NSE was observed. The initial values of S-100B and NSE in acute subdural hematomas with unfavorable outcome were significantly higher than in those with favorable outcome. Secondary increase of serum markers was associated with the presence of secondary insult such as hypoxia or hypotension, and was found to have an unfavorable outcome. CONCLUSIONS: Serum concentration and kinetics of S-100B protein and NSE provide the clinical assessment of the primary brain damage and have a predictive value for outcome after traumatic brain injury.     

The impact of prehospital endotracheal intubation on outcome in moderate to severe traumatic brain injury

BACKGROUND: Although early intubation to prevent the mortality that accompanies hypoxia is considered the standard of care for severe traumatic brain injury (TBI), the efficacy of this approach remains unproven. METHODS: Patients with moderate to severe TBI (Head/Neck Abbreviated Injury Scale [AIS] score 3+) were identified from our county trauma registry. Logistic regression was used to explore the impact of prehospital intubation on outcome, controlling for age, gender, mechanism, Glasgow Coma Scale score, Head/Neck AIS score, Injury Severity Score, and hypotension. Neural network analysis was performed to identify patients predicted to benefit from prehospital intubation. RESULTS: A total of 13,625 patients from five trauma centers were included; overall mortality was 22.9%, and 19.3% underwent prehospital intubation. Logistic regression revealed an increase in mortality with prehospital intubation (odds ratio, 0.36; 95% confidence interval, 0.32-0.42; p < 0.001). This was true for all patients, for those with severe TBI (Head/Neck AIS score 4+ and/or Glasgow Coma Scale score of 3-8), and with exclusion of patients transported by aeromedical crews. Patients intubated in the field versus the emergency department had worse outcomes. Neural network analysis identified a subgroup of patients with more significant injuries as potentially benefiting from prehospital intubation. CONCLUSION: Prehospital intubation is associated with a decrease in survival among patients with moderate-to-severe TBI. More critically injured patients may benefit from prehospital intubation but may be difficult to identify prospectively.     

Determinants of hospital costs associated with traumatic brain injury in England and Wales

Using data from the Trauma Audit Research Network, we investigated the costs of acute care in patients > or = 18 years of age hospitalised for traumatic brain injury between January 2000 and December 2005 in England and Wales. Traumatic brain injury patients were defined and stratified using the Abbreviated Injury Scale. A total of 6484 traumatic brain injury patients were identified; 22.3% had an Abbreviated Injury Scale score of three, 38.0% of four and 39.7% of five. Median age (IQR) was 42 years (28-59) and 76.7% were men. Primary cause of injury was motor vehicle collisions (42.4%) followed by falls (38.0%). In total 23.7% of the patients died before discharge. Hospitalisation costs averaged 15,462 pounds sterling (SD 16,844 pounds sterling). Costs varied significantly by age, Glasgow Coma Score, Injury Severity Score, coexisting injuries of the thorax, spine and lower limb, hospital mortality, availability of neurosurgical services, and specialty of attendants seen in the Accident and Emergency department.     

The deleterious effects of intraoperative hypotension on outcome in patients with severe head injuries.

Prehospital or admission hypotension doubles the mortality for patients with severe head injury (SHI = Glasgow Coma Scale score less than or equal to 8). To our knowledge no study to date has determined the effects of intraoperative hypotension [IH: systolic blood pressure (SBP) less than 90 mm Hg] on outcome in patients with SHI. This study examined 53 patients who had SHI and required early surgical intervention (surgery within 72 hours of injury). All patients were initially normotensive on arrival. There were 17 patients (32%) who developed IH and 36 (68%) who remained normotensive throughout surgery. The mortality rate was 82% in the IH group and 25% in the normotensive group (p less than 0.001). The duration of IH was inversely correlated with Glasgow Outcome Scale using linear regression (R = -0.30; p = 0.02). Despite vigorous fluid resuscitation in the IH group, additional pharmacologic support was used in only 32%. These data suggest that IH is not uncommon after SHI (32%) and that it does have a significant effect on patient outcome.     

Use of injury severity variables in determining disability and community integration after traumatic brain injury

BACKGROUND: Long-term outcome is important in managing traumatic brain injury (TBI), an epidemic in the United States. Many injury severity variables have been shown to predict major morbidity and mortality. Less is known about their relationship with specific long-term outcomes. METHODS: Glasgow Coma Scale, Revised Trauma Score, Injury Severity Score, and Trauma and Injury Severity Score, along with other demographic and premorbid values, were obtained for 378 consecutive patients hospitalized after TBI at a Level I trauma center between September 1997 and May 1998. Of this cohort, 120 patients were contacted for 1-year follow-up assessment with the Disability Rating Scale, Community Integration Questionnaire, and employment data. RESULTS: Univariate analyses showed these to be significant single predictors of 1-year outcome. Multivariate analyses revealed that the Revised Trauma Score and Glasgow Coma Scale had significant additive value in predicting injury variables Disability Rating Scale scores when combined with other demographic and premorbid variables studied. Predictive models of 1-year outcome were developed. CONCLUSION: Injury severity variables are significant single outcome predictors and, in combination with premorbid and demographic variables, help predict long-term disability and community integration for individuals hospitalized with TBI.     

Hyperglycemia and outcomes from pediatric traumatic brain injury

BACKGROUND: The clinical significance of hyperglycemia after pediatric traumatic brain injury is controversial. This study addresses the relationship between hyperglycemia and outcomes after traumatic brain injury in pediatric patients. METHODS: We identified trauma patients admitted during a single year to our regional pediatric referral center with head regional Abbreviated Injury Scale scores > or = 3. We studied identified patients for admission characteristics potentially influencing their outcomes. The primary outcome measure was Glasgow Outcome Scale score. RESULTS: Patients who died had significantly higher admission serum glucose values than those patients who survived (267 mg/dL vs. 135 mg/dL; p = 0.000). Admission serum glucose > or = 300 mg/dL was uniformly associated with death. Admission Glasgow Coma Scale score (odds ratio, 0.560; 95% confidence interval, 0.358-0.877) and serum glucose (odds ratio, 1.013; 95% confidence interval, 1.003-1.023) are independent predictors of mortality in children with traumatic head injuries. CONCLUSION Hyperglycemia and poor neurologic outcome in head-injured children are associated. The pathophysiology of hyperglycemia in neurologic injury after head trauma remains unclear.     

Isolated brain injury as a cause of hypotension in the blunt trauma patient

BACKGROUND: Emerging evidence suggests that, contrary to standard teaching, isolated brain injury may be associated with hypotension. This study sought to determine the frequency of isolated brain injury-induced hypotension in blunt trauma victims. METHODS: Hypotensive adult trauma patients were categorized according to the cause of hypotension: hemorrhagic (hemoglobin < 11.0), neurogenic, isolated brain, or other. Their clinical data and outcomes were compared. RESULTS: The cause of hypotension was hemorrhagic in 113 (49%), isolated brain injury in 30 (13%), neurogenic in 14 (6%), and other causes in 24 (10%). Fifty (22%) were indeterminate. Hemorrhagic, isolated brain, and neurogenic groups were similar in age, Injury Severity Score, and systolic blood pressure. The Glasgow Coma Scale score of the isolated brain group was lower than in the hemorrhagic group (4.4 vs. 8.4, p < 0.05). Mortality was higher in the isolated brain group compared with the hemorrhagic group (80% vs. 50%, p < 0.05) and in the subgroup of hemorrhagic patients with versus without associated brain injury (57% vs. 39%, p < 0.05). CONCLUSION: Isolated brain injuries account for 13% of hypotensive events after blunt trauma and are associated with an increased mortality compared with hemorrhage-induced hypotension. In hypotensive brain-injured patients, hemorrhagic sources should be excluded rapidly, and the focus should be on resuscitation.     

Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury

OBJECTIVES: There is an absence of prospective data evaluating the impact of prehospital intubation in adult trauma patients. Our objectives were to determine the outcome of trauma patients intubated in the field who did not have an acutely lethal traumatic brain injury (death within 48 hours) compared with patients who were intubated immediately on arrival to the hospital. METHODS: Prospective data were collected on 191 consecutive patients admitted to the trauma center with a field Glasgow Coma Scale score < or = 8 and a head Abbreviated Injury Scale score > or = 3 who were either intubated in the field or intubated immediately at admission to the hospital. Patients who died within 48 hours of admission and transfers were excluded from the study. RESULTS: Of the 191 patients, 176 (92%) sustained blunt trauma and 25 (8%) were victims of penetrating trauma. Seventy-eight (41%) of the 191 patients were intubated in the field and 113 (59%) were intubated immediately at admission. There was no significant difference in age, Glasgow Coma Scale score, head Abbreviated Injury Scale score, or Injury Severity Score between the two groups. Patients who were intubated in the field had a significantly higher morbidity (ventilator days, 14.7 vs. 10.4; hospital days, 20.2 vs. 16.7; and intensive care unit days, 15.2 vs. 11.7) compared with patients intubated on immediate arrival to the hospital and nearly double the mortality (23% vs. 12.4). Field-intubated patients had a 1.5 times greater risk of nosocomial pneumonia compared with hospital-intubated patients. CONCLUSION: Prehospital intubation is associated with a significant increase in morbidity and mortality in trauma patients with traumatic brain injury who are admitted to the hospital without an acutely lethal injury. A randomized, prospective study is warranted to confirm these results.     

Extracranial insults and outcome in patients with acute head injury--relationship to the Glasgow Coma Scale

Hypoxia and hypotension are extracranial insults known to have an adverse effect on the outcome of patients with acute head injury. Arterial oxygen tension, blood pressure and the Glasgow Coma Score on admission of 67 patients seen over a 6-month period were correlated with the outcome at 6 months. With a given level of consciousness the presence of an extracranial insult resulted in a worse outcome than would be predicted. The combination of hypoxia and hypotension was uniformly fatal as was the presence of severe respiratory dysfunction.     

Early physiologic predictors of injury severity and death in blunt multiple trauma

The importance of admission physiological and biochemical variables was modeled on data from 185 patients with blunt liver trauma with regard to their significance in prediction of mortality. The variables used were admission Glasgow Coma Score, base excess (or deficit), arterial lactate, Injury Severity Score, and initial 24-hour volume of blood required for replacement. Each variable was modeled as a predictor of survival alone and in combination, using a linear logistic model. In any two-variable combination, Glasgow Coma Score had a high likelihood ratio for prediction representing the influence of brain injury. But as a single variable reflecting the probability of death, both base excess (LD50 = -11.8 mmol/L) and initial 24-hour volume of blood (LD50 = 5.4 L) were highly significant. A combined logistic model of admission Glasgow Coma Score and base excess had the greatest likelihood of accurate prediction of outcome: P death = e lambda/l + e lambda; where lambda = -0.21(Glasgow Coma Score) -0.147(base excess) + 0.285. Testing of this predictive model on data from 323 additional patients with multiple trauma who had pelvic fracture as their index injury also showed it to be a highly significant early predictor of outcome.     

Investigating gender differences in outcome following severe traumatic brain injury in a predominantly Asian population

The objective of this study was to investigate if there are possible gender differences in relation to outcome following closed severe traumatic brain injury (TBI) in a predominantly Asian population. A study was conducted using our prospectively maintained TBI database of 672 patients with severe TBI admitted into our neurosurgical intensive care unit. All patients were managed on a standardized protocol in accordance with the Guidelines to the management of severe traumatic brain injury. Glasgow Outcome Score was used to measure the outcome of patients 6 months postinjury. There were 525 males and 147 females, with the latter significantly older than their counterpart. Females had a significantly higher mortality and poorer outcome compared with males. However, this difference was no longer significant when variables (presence of multiple injuries, postresuscitation pupil abnormalities and Glasgow Coma Score) are controlled for. However, both crude and adjusted odd ratios revealed that females aged 60 and below were significantly more likely to have a poorer outcome.     

Outcome and prognostic factors in head injuries with an admission Glasgow Coma Scale score of 3

HYPOTHESIS: To identify significant risk factors associated with mortality in patients with a Glasgow Coma Scale score of 3. DESIGN: Trauma registry study. SETTING: Level I urban trauma center. PATIENTS: A total of 760 patients with head injury with an admission Glasgow Coma Scale score of 3. Analysis was performed in all patients and in only patients who reached the hospital alive and had no major extracranial injuries (exclusion of patients with a chest or abdominal Abbreviated Injury Score [AIS] >3). MAIN OUTCOME MEASURES: Stepwise logistic regression analysis was used to identify independent risk factors associated with mortality. RESULTS: Blunt trauma accounted for 477 (63%) and penetrating trauma for 283 (37%) of the 760 head injuries. Penetrating trauma was significantly more likely to be associated with a lack of vital signs on admission (15% vs 9%; P = .03). Overall mortality was 76% (94% for penetrating injuries and 65% for blunt injuries; P<.001). Overall, 79% of patients had a head AIS of 4 or greater. Mortality in the subgroup was 64% (320/497) and was significantly higher in penetrating vs blunt trauma (89% vs 52%; P<.001). Penetrating trauma, high head AIS, hypotension on admission, and age older than 55 years were independent significant risk factors associated with mortality. Only 10% of the 177 survivors had good functional outcome at hospital discharge. Eighty-six patients (17% of those with vital signs on admission) became organ donors. CONCLUSIONS: Patients with head injury with an admission Glasgow Coma Scale score of 3 have a poor prognosis. Mechanism of injury, head AIS, hypotension on admission, and age play a critical role in outcome. These patients are an important source of organ donation and should be evaluated and resuscitated aggressively.     

Influence of extraneurological insults on ventricular enlargement and neuropsychological functioning after moderate and severe traumatic brain injury

Extraneurological insults secondary to TBI such as hypotension or hypoxia have been associated with mortality and morbidity. The purpose of this study was to investigate the influence of systemic complications on both neuropsychological outcome and cerebral atrophy. Fifty-seven patients selected from 122 consecutive admissions were studied. Data on the type and severity of injury as well as other systemic insults were collected prior to and during the first 3 days of hospitalization. These data included the presence or absence of a hypoxic episode during the pre-hospital period, the presence and degree of hypoxia, hypercapnia, anemia, hypotension and intracranial hypertension, pupillary reactivity, Glasgow Coma Scale score and coma duration. From the last control CT scan image, performed 6 months post-injury, four different indexes of ventricular dilatation were calculated. Neuropsychological assessment at 6 months included tests of verbal and visual memory, visuoconstructive functions, fine motor speed, and frontal lobe functions. Our results showed that hypoxia and hypotension were related to neuropsychological outcome and long-term ventricular enlargement. Hypoxic episodes prior to hospitalization were related to third ventricle dilatation and to adverse neurological and cognitive outcomes, especially to attention, motor speed, mental flexibility, fluency and verbal memory impairments, suggesting fronto-striatal and hippocampal dysfunction. We conclude that the effect of extraneurological insults on brain structure and function may be as important as the severity of the primary injury.     

Cerebral oxygenation, vascular reactivity, and neurochemistry following decompressive craniectomy for severe traumatic brain injury

OBJECT: This study addresses the changes in brain oxygenation, cerebrovascular reactivity, and cerebral neurochemistry in patients following decompressive craniectomy for the control of elevated intracranial pressure (ICP) after severe traumatic brain injury (TBI). METHODS: Sixteen consecutive patients with isolated TBI and elevated ICP, who were refractory to maximal medical therapy, underwent decompressive craniectomy over a 1-year period. Thirteen patients were male and 3 were female. The mean age of the patients was 38 years and the median Glasgow Coma Scale score on admission was 5. RESULTS Six months following TBI, 11 patients had a poor outcome (Group 1, Glasgow Outcome Scale [GOS] Score 1-3), whereas the remaining 5 patients had a favorable outcome (Group 2, GOS Score 4 or 5). Decompressive craniectomy resulted in a significant reduction (p < 0.001) in the mean ICP and cerebrovascular pressure reactivity index to autoregulatory values (< 0.3) in both groups of patients. There was a significant improvement in brain tissue oxygenation (PbtO(2)) in Group 2 patients from 3 to 17 mm Hg and an 85% reduction in episodes of cerebral ischemia. In addition, the durations of abnormal PbtO(2) and biochemical indices were significantly reduced in Group 2 patients after decompressive craniectomy, but there was no improvement in the biochemical indices in Group 1 patients despite surgery. CONCLUSIONS: Decompressive craniectomy, when used appropriately in protocol-driven intensive care regimens for the treatment of recalcitrant elevated ICP, is associated with a return of abnormal metabolic parameters to normal values in patients with eventually favorable outcomes.