The effects of mild hypothermia on patients with severe traumatic brain injury

Objective To investigate the protectiveeffects of mild hypothermia(33-35℃)on theoutcome of patients with severe traumaticbrain injury(TBI)(GCS<8). Methods Patients in the mild hypother-mia group were cooled to 33-35℃by coolingblanket with muscular relaxant,and patientsin the normothermia group were maintained at37-38℃. Results The result showed that the mor-     

Normobaric hyperoxia in traumatic brain injury: does brain metabolic state influence the response to hyperoxic challenge?

This study sought to investigate whether normobaric hyperoxia (NH) improves brain oxygenation and brain metabolism in the early phase of severe and moderate traumatic brain injury (TBI) and whether this effect occurs uniformly in all TBI patients. Thirty patients (9 women and 21 men) with a median initial Glasgow Coma Score (GCS) of 6 (range, 3-12) were monitored using a brain microdialysis (MD) catheter with a brain tissue oxygen sensor (PtiO(2)) placed in the least-injured hemisphere. The inspired oxygen fraction was increased to 100% for 2 h. Patients were divided into two groups: Group 1: patients with baseline brain lactate ≤3 mmol/L and Group 2: patients with baseline brain lactate >3 mmol/L, and therefore increased anaerobic metabolism in the brain. In Group 1, no significant changes in brain metabolic parameters were found after hyperoxic challenge, whereas a significant increase in glucose and a decrease in the lactate-pyruvate ratio (LPR) were found in Group 2. In this latter group of patients, brain glucose increased on average by 17.9% (95% CI, +9.2% to +26.6%, p<0.001) and LPR decreased by 11.6% (95% CI, -16.2% to -6.9%, p<0.001). The results of our study show that moderate and severe TBI may induce metabolic alterations in the brain, even in macroscopically normal brain tissue. We observed that NH increased PaO(2) and PtiO(2) and significantly decreased LPR in patients in whom baseline brain lactate levels were increased, suggesting that NH improved the brain redox state. In patients with normal baseline brain lactate levels, we did not find any significant changes in the metabolic variables after NH. This suggests that the baseline metabolic state should be taken into account when applying NH to patients with TBI. This maneuver may only be effective in a specific group of patients.     

Extracorporeal membrane oxygenation and severe traumatic brain injury. Is the ECMO-therapy in traumatic lung failure and severe traumatic brain injury really contraindicated?

Veno-venous extracorporeal membrane oxygenation (ECMO) may be lifesaving in multiple injured patients with acute respiratory distress syndrome (ARDS) due to chest trauma. To prevent circuit thrombosis or thrombembolic complications during ECMO systemic anticoagulation is recommended. Therefore, ECMO treatment is contraindicated in patients with intracranial bleeding. The management of veno-venous ECMO without systemic anticoagulation in a patient suffering from traumatic lung failure and severe traumatic brain injury is reported.     

Significance of serum neuron-specific enolase in patients with acute traumatic brain injury

OBJECTIVE: To study the association between serum neuron-specific enolase (NSE) and the extent of brain damage and the outcome after acute traumatic brain injury (TBI). METHODS: The release patterns of serum NSE in 78 patients after acute TBI were analyzed by using the enzyme linked immunosorbent assay. The levels of NSE were compared with Glasgow coma scale, the category of brain injury and the outcome after 6 months of injury. RESULTS: There were different NSE values in patients with minor (12.96 microg/L+/-2.39 microg/L), moderate (23.44 microg/L+/-5.33 microg/L) and severe brain injury (42.68 microg/L+/-4.57 microg/L). After severe TBI, the concentration of NSE in patients with epidural hematomas was 13.38 microg/L+/-4.01 microg/L, 24.03 microg/L+/-2.85 microg/L in brain contusion without surgical intervention group, 55.20 microg/L+/-6.35 microg/L in brain contusion with surgical intervention group, and 83.85 microg/L+/-15.82 microg/L in diffuse brain swelling group. There were close correlations between NSE values and Glasgow coma scale (r=-0.608, P<0.01) and the extent of brain injury (r=0.75, P<0.01). Patients with poor outcome had significantly higher initial and peak NSE values than those with good outcome (66.40 microg/L+/-9.46 microg/L, 94.24 microg/L+/-13.75 microg/L vs 32.16 microg/L+/-4.21 microg/L, 34.08 microg/L+/-4.40 microg/L, P<0.01, respectively). Initial NSE values were negatively related to the outcome (r=-0.501, P<0.01). Most patients with poor outcomes had persisting or secondary elevated NSE values. CONCLUSIONS: Serum NSE is one of the valuable neurobiochemical markers for assessment of the severity of brain injury and outcome prediction.     

Pituitary functions in the acute phase of traumatic brain injury: are they related to severity of the injury or mortality?

Primary objective: There are only limited data regarding pituitary functions in the acute phase of traumatic brain injury (TBI) and previous studies have been conducted in only small cohorts of subjects. Therefore we have investigated the pituitary functions in the early acute phase, within 24 hours of trauma, in 104 patients with TBI. Additionally, the relationships between basal pituitary hormones, severity of the trauma and mortality due to trauma were also investigated.

Methods and procedures: One hundred and four TBI patients were included in the study consecutively. All patients underwent basal hormonal evaluation within the first 24 hours of admission. Twenty of 104 patients died during the acute phase.

Main outcomes: Prolactin levels were negatively correlated with the Glasgow coma scale (GCS), cortisol levels were positively correlated with the GCS and cortisol levels were positively correlated with ACTH levels. Additionally there was a significant positive correlation between the total testosterone levels and the GCS in males. Logistic regression analysis revealed that mortality after TBI was unrelated to basal pituitary hormone levels. However age and GCS were significantly related to the mortality. The percentages of pituitary hormone deficiencies were as follows: 3.8% had TSH deficiency, 40.0% had gonadotrophin deficiency, 8.8% had ACTH deficiency and 20.0% had GH deficiency.

Conclusions: Present data clearly demonstrate that pituitary function is disturbed in TBI and the most frequently deficient pituitary hormones were gonadotrophins in the early acute phase of TBI. Basal hormone levels including cortisol, prolactin and total testosterone were related to the severity of the trauma. However there was no relation between basal hormones and mortality due to TBI. Age and GCS were significantly related to mortality.     

Severe traumatic brain injury: is there a gender difference in mortality?

Background

Emerging evidence suggests that male and female nervous systems respond differently to traumatic brain injury (TBI). The objective of this study was to examine outcomes between the sexes after TBI.

Patients and methods

A retrospective review of all severe TBI patients admitted between January and December 2005 was performed. Isolated severe TBI was defined as a head abbreviated injury score greater than 3 with an abbreviated injury score of 3 or less for other anatomic regions. The population was stratified into age subgroups (<14 y, 14-44 y, 45-54 y, and ≥55 y). Logistic regression was used to identify independent predictors of mortality.

Results

A total of 1,807 TBI patients were admitted. The mortality was significantly higher for women (43.2% vs 36.2%, P < .01) with an adjusted odds ratio of 1.4 (95% confidence interval, 1.1-1.9, P < .05). After stratification, only women age 55 and older had a significant difference in mortality (odds ratio, 1.71; 95% confidence interval, 1.11-2.62, P = .02).

Conclusions

Female sex (particularly those age ≥55 y) is associated independently with higher mortality in isolated severe TBI. This increased mortality of postmenopausal women after isolated TBI may suggest a hormonal influence and warrants further investigation.     

Thrombocytopenia after therapeutic hypothermia in severe traumatic brain injury

Objective: To investigate the clinical characteristics and significance of thrombocytopenia after therapeutic hypothermia in severe traumatic brain injury (TBI). Methods:Ninety-six inpatients with severe brain injury were randomized into three groups: SBC (selective brain cooling) group (n=24), MSH (mild systemic hypothermia ) group (n=30), and control (normothermia) group (n=42). The platelet counts and prognosis were retrospectively analyzed. Results: Thrombocytopenia was present in 18 (75%), 23 (77%) and 15 (36%) patients in SBC group, MSH group and control group, respectively (P<0. 01). Thrombocytopenia, in which the minimum platelet count was seen 3 days after hypothermia, showed no significant difference between SBC and MSH group (P>0.05). Most platelet counts (37 cases, 90 %) in hypothermia group were returned to normal level after 1 to 2 days of natural rewarming. The platelet count in SBC group reduced by 16%, 27% and 29% at day 1, 3 and 5 respectively compared with the baseline value. Good recovery ( GOS score 4-5) rate of thrombocytopenia 1 year after injury for hypothermia group (17 cases, 37%) was significantly lower than that of control group (P < 0.01). Conclusions: Therapeutic hypothermia increases the incidence of thrombocytopenia in severe TBI, and patients with thrombocytopenia after therapeutic hypothermia are associated with unfavorable neurological prognosis.     

Can bispectral index monitoring predict recovery of consciousness in patients with severe brain injury?

BACKGROUND: The probability of recovering consciousness in acute brain-injured patients depends on central nervous system damage and complications acquired during their stay in the intensive care unit. The objective of this study was to establish a relation between the Bispectral Index (BIS) and other variables derived from the analysis of the electroencephalographic signal, with the probability of recovering consciousness in patients in a coma state due to severe cerebral damage. METHODS: Twenty-five critically ill, unconscious brain-injured patients from whom sedative drugs were withdrawn at least 24 h before BIS recording were prospectively studied. BIS, 95% spectral edge frequency, burst suppression ratio, and frontal electromyography were recorded for 20 min. The neurologic condition of the patients was measured according to the Glasgow Coma Score (GCS). Patients were followed up for assessment of recovery of consciousness for 6 months after the injury. The studied variables were compared between the group of patients who recovered consciousness and those who did not recover. Their predictive ability was evaluated by means of the Pk statistic. Univariate and multivariate logistic regression was used to model the relation between variables and probability of recovery of consciousness. Cross-validation was used to validate the proposed model. RESULTS: There were statistically significant differences between the group of patients who recovered consciousness and those who did not with respect to BISmax, BISmin, BISmean, and BISrange, frontal electromyography, signal quality index values, and GCSBIS. The Pk (SE) values were 0.99 (0.01) for electromyelography, 0.96 (0.05) for BISmax, 0.92 (0.05) for BISmean, 0.92 (0.06) for BISrange, and 0.82 (0.09) for GCSBIS. The odds ratio for BISmax in the logistic regression model was 1.17 (95% confidence interval, 1.1-1.35). Cross-validation results reported a high-accuracy median absolute cross-validation performance error of 3.06% (95% confidence interval, 1-22.15%) and a low-bias median cross-validation performance error of 0.84% (0.56-2.12%). CONCLUSIONS: The study BIS and other electrophysiologic and clinical variables has enabled construction and cross-validation of a model relating BIS(max) to the probability of recovery of consciousness in patients in a coma state due to a severe brain injury, after sedation has been withdrawn.     

Does an early onset and continuous chain of rehabilitation improve the long-term functional outcome of patients with severe traumatic brain injury?

There are currently no international guidelines regarding treatment in the early rehabilitation phase for persons with severe traumatic brain injury (TBI), and only a few studies have investigated the effect of integrating rehabilitation into acute TBI care. The aim of the study was to evaluate whether a continuous chain of rehabilitation that begins with the acute phase could improve the functional outcome of severe TBI patients, compared to a broken chain of rehabilitation that starts in the sub-acute phase of TBI. A total of 61 surviving patients with severe TBI were included in a quasi-experimental study conducted at the Level I trauma center in Eastern Norway. In the study, 31 patients were in the early rehabilitation group (Group A) and 30 patients were in the delayed rehabilitation group (Group B). The functional outcomes were assessed 12 months post-injury with the Glasgow Outcome Scale Extended (GOSE) and the Disability Rating Scale (DRS). A favorable outcome (GOSE 6-8) occurred in 71% of the patients from Group A versus 37% in Group B (p=0.007). The DRS score was significantly better in Group A (p=0.03). The ordinal logistic regression analysis was used to quantify the relationship between the type of rehabilitation chain and the GOSE. A better GOSE outcome was found in patients from Group A (unadjusted OR 3.25 and adjusted OR 2.78, respectively). These results support the hypothesis that better functional outcome occurs in patients who receive early onset and a continuous chain of rehabilitation.     

Increased inattentional blindness in severe traumatic brain injury: evidence for reduced distractibility?

Primary objective: To examine the role of selective attention and visual perception in medicating inattentional blindness in a severe traumatic brain injured sample.

Research design: Cross-sectional design with age and education matched control sample.

Methods and procedures: Twenty participants with severe traumatic brain injury (n = 10) and matched controls (n = 10) completed a series of tests of focused attention (Stroop test), divided attention (Trail Making Test), visual perception (Visual Object and Space Perception Battery) and two tasks of inattentional blindness.

Main outcomes and results: The group with severe TBI were significantly slower on the Stroop test and TMT and displayed significantly elevated Stroop interference and TMT ratio scores. On the inattentional blindness tasks, fewer TBI participants identified a distracting stimulus.

Conclusion: The results indicate severe TBI is associated with deficits to focused and divided attention with the finding of a potentially more debilitating impairment arising from reduced distractibility following severe TBI.     

Predicting 14-day mortality after severe traumatic brain injury: application of the IMPACT models in the brain trauma foundation TBI-trac® New York State database

Prognostic models for outcome prediction in patients with traumatic brain injury (TBI) are important instruments in both clinical practice and research. To remain current a continuous process of model validation is necessary. We aimed to investigate the performance of the International Mission on Prognosis and Analysis of Clinical Trials in TBI (IMPACT) prognostic models in predicting mortality in a contemporary New York State TBI registry developed and maintained by the Brain Trauma Foundation. The Brain Trauma Foundation (BTF) TBI-trac? database contains data on 3125 patients who sustained severe TBI (Glasgow Coma Scale [GCS] score ≤ 8) in New York State between 2000 and 2009. The outcome measure was 14-day mortality. To predict 14-day mortality with admission data, we adapted the IMPACT Core and Extended models. Performance of the models was assessed by determining calibration (agreement between observed and predicted outcomes), and discrimination (separation of those patients who die from those who survive). Calibration was explored graphically with calibration plots. Discrimination was expressed by the area under the receiver operating characteristic (ROC) curve (AUC). A total of 2513 out of 3125 patients in the BTF database met the inclusion criteria. The 14-day mortality rate was 23%. The models showed excellent calibration. Mean predicted probabilities were 20% for the Core model and 24% for the Extended model. Both models showed good discrimination with AUCs of 0.79 (Core) and 0.83 (Extended). We conclude that the IMPACT models validly predict 14-day mortality in the BTF database, confirming generalizability of these models for outcome prediction in TBI patients.     

Does sexual dimorphism influence outcome of traumatic brain injury patients? The answer is no!

BACKGROUND: The protective effect of female gender on posttraumatic mortality or acute complications after traumatic brain injury (TBI) has been postulated. This effect might be seen if TBIs were analyzed by severity. To assess potential gender effects, we performed a retrospective case-controlled study matching female patients to male counterparts for overall injury severity; hemodynamic status at admission; and head, chest, and abdomen Abbreviated Injury Scale score. METHODS: All female patients sustaining TBI admitted over 6.5 years were reviewed. An overall comparison between women (n = 914) and their male matched counterparts (n = 916) was performed. Patients were then stratified according to the severity of head injury on the basis of admission Glasgow Coma Scale (GCS) score into three groups: group 1, GCS score of 13 to 15 (788 female patients, 769 male patients); group 2, GCS score of 9 to 12 (40 female patients, 42 male patients); and group 3, GCS score < 9 (63 female patients, 87 male patients). Cohorts were compared for mortality or the development of acute respiratory distress syndrome, pneumonia, and systemic sepsis using standard definitions. A subset analysis was performed excluding patients with age above 50 years (789 women, 811 men) to exclude the effects of menopause on the results. RESULTS: There was no statistically significant difference in outcome overall or in subset analysis of mild (group 1), moderate (group 2), or severe (group 3) TBI. The exclusion of patients older than 50 years showed no protective effect of female gender on outcome. CONCLUSION: Gender does not play a role in posttraumatic mortality or in the incidence of acute complications after any degree of TBI.