Glucose control and mortality in patients with severe traumatic brain injury

Admission Blood Glucose Level as a Predictor of Outcome in Intensive Care Patients: A Cross-Sectional Study

INTRODUCTION

In the Intensive care unit (ICU), hyperglycemia is often observed; commonly associated with pre-existing diabetes or pre-diabetes or in nondiabetic patients. This study aimed to assess the role of admission blood sugar levels with outcomes in ICU patients.

METHODS

A total of 100 patients above 18 years of age were included in the study. A detailed history regarding the patient's age, sex, and any chronic illness were taken. Heart rate, systolic blood pressure, and Glasgow coma scale (GCS) scores were recorded. Admission blood glucose level, blood urea, total leucocyte count, and serum electrolytes were measured; and the outcome was noted.

RESULTS

The number of diabetics was significantly higher (65.5%) in the random blood sugar (RBS) ≥180 group. Hyponatremia was significantly associated with hyperglycemia. Patients with hyperglycemia had serum bicarbonate <18. A significantly greater number of patients with hyperglycemia had GCS scores of <8, and required mechanical ventilation. The duration of ICU stay and non-survivors were significantly higher in the hyperglycemia group. Random blood sugar at admission as a factor to assess outcome showed a sensitivity of 68.4 and specificity of 59.3 with a cut-off value of 197.

CONCLUSION

Admission of random blood sugar was significantly associated with poor outcomes. More stringent surveillance as well as routine blood glucose checks at the time of hospital admission should be emphasized.

The Richmond Acute Subdural Hematoma Score: A Validated Grading Scale to Predict Postoperative Mortality

BACKGROUND

Traumatic acute subdural hematomas (aSDHs) are common, life-threatening injuries often requiring emergency surgery.

OBJECTIVE

To develop and validate the Richmond acute subdural hematoma (RASH) score to stratify patients by risk of mortality after aSDH evacuation.

METHODS

The 2016 National Trauma Data Bank (NTDB) was queried to identify adult patients with traumatic aSDHs who underwent craniectomy or craniotomy within 4 h of arrival to an emergency department. Multivariate logistic regression modeling identified risk factors independently associated with mortality. The RASH score was developed based on a factor's strength and level of association with mortality. The model was validated using the 2017 NTDB and the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 2516 cases met study criteria. The patients were 69.3% male with a mean age of 55.7 yr and overall mortality rate of 36.4%. Factors associated with mortality included age between 61 and 79 yr (odds ratio [OR] = 2.3, P < .001), age ≥80 yr (OR = 6.3, P < .001), loss of consciousness (OR = 2.3, P < .001), Glasgow Coma Scale score of ≤8 (OR = 2.6, P < .001), unilateral (OR = 2.8, P < .001) or bilateral (OR = 3.9, P < .001) unresponsive pupils, and midline shift >5 mm (OR = 1.7, P < .001). Using these risk factors, the RASH score predicted progressively increasing mortality ranging from 0% to 94% for scores of 0 to 8, respectively (AUC = 0.72). Application of the RASH score to 3091 cases from 2017 resulted in similar accuracy (AUC = 0.74).

CONCLUSION

The RASH score is a simple and validated grading scale that uses easily accessible preoperative factors to predict estimated mortality rates in patients with traumatic aSDHs who undergo surgical evacuation.

Glycemic targets in critically ill adults: A mini-review

Illness-induced hyperglycemia impairs neutrophil function, increases pro-inflammatory cytokines, inhibits fibrinolysis, and promotes cellular damage. In turn, these mechanisms lead to pneumonia and surgical site infections, prolonged mechanical ventilation, prolonged hospitalization, and increased mortality. For optimal glucose control, blood glucose measurements need to be done accurately, frequently, and promptly. When choosing glycemic targets, one should keep the glycemic variability < 4 mmol/L and avoid targeting a lower limit of blood glucose < 4.4 mmol/L. The upper limit of blood glucose should be set according to casemix and the quality of glucose control. A lower glycemic target range (i.e., blood glucose 4.5-7.8 mmol/L) would be favored for patients without diabetes mellitus, with traumatic brain injury, or who are at risk of surgical site infection. To avoid harm from hypoglycemia, strict adherence to glycemic control protocols and timely glucose measurements are required. In contrast, a higher glycemic target range (i.e., blood glucose 7.8-10 mmol/L) would be favored as a default choice for medical-surgical patients and patients with diabetes mellitus. These targets may be modified if technical advances for blood glucose measurement and control can be achieved.

Patterns and Effects of Admission Hyperglycemia and Inflammatory Response in Trauma Patients: A Prospective Clinical Study

BACKGROUND

The constellation of the initial hyperglycemia, proinflammatory cytokines and severity of injury among trauma patients is understudied. We aimed to evaluate the patterns and effects of on-admission hyperglycemia and inflammatory response in a level 1 trauma center. We hypothesized that higher initial readings of blood glucose and cytokines are associated with severe injuries and worse in-hospital outcomes in trauma patients.

METHODS

A prospective, observational study was conducted for adult trauma patients who were admitted and tested for on-admission blood glucose, hemoglobin A1c, interleukin (IL)-6, IL-18 and hs-CRP. Patients were categorized into four groups [non-diabetic normoglycemic, diabetic normoglycemic, diabetic hyperglycemic (DH) and stress-induced hyperglycemic (SIH)]. The inflammatory markers were measured on three time points (admission, 24 h and 48 h). Generalized estimating equations (GEE) were used to account for the correlation for the inflammatory markers. Pearson's correlation test and logistic regression analysis were also performed.

RESULTS

During the study period, 250 adult trauma patients were enrolled. Almost 13% of patients presented with hyperglycemia (50% had SIH and 50% had DH). Patients with SIH were younger, had significantly higher Injury Severity Score (ISS), higher IL-6 readings, prolonged hospital length of stay and higher mortality. The SIH group had lower Revised Trauma Score (p = 0.005), lower Trauma Injury Severity Score (p = 0.01) and lower GCS (p = 0.001). Patients with hyperglycemia had higher in-hospital mortality than the normoglycemia group (12.5% vs 3.7%; p = 0.02). A significant correlation was identified between the initial blood glucose level and serum lactate, IL-6, ISS and hospital length of stay. Overall rate of change in slope 88.54 (95% CI:-143.39-33.68) points was found more in hyperglycemia than normoglycemia group (p = 0.002) for IL-6 values, whereas there was no statistical significant change in slopes of age, gender and their interaction. The initial IL-6 levels correlated with ISS (r = 0.40, p = 0.001). On-admission hyperglycemia had an adjusted odds ratio 2.42 (95% CI: 1.076-5.447, p = 0.03) for severe injury (ISS > 12) after adjusting for age, shock index and blood transfusion.

CONCLUSIONS

In trauma patients, on-admission hyperglycemia correlates well with the initial serum IL-6 level and is associated with more severe injuries. Therefore, it could be a simple marker of injury severity and useful tool for patient triage and risk assessment.

TRIAL REGISTRATION

This study was registered at the ClinicalTrials.gov (Identifier: NCT02999386), retrospectively Registered on December 21, 2016. https://clinicaltrials.gov/ct2/show/NCT02999386 .

An Artificial Neural Network-based Predictive Model to Support Optimization of Inpatient Glycemic Control

Background: Achieving glycemic control in critical care patients is of paramount importance, and has been linked to reductions in mortality, intensive care unit (ICU) length of stay, and morbidities such as infection. The myriad of illnesses and patient conditions render maintenance of glycemic control very challenging in this setting. Materials and Methods: This study involved collection of continuous glucose monitoring (CGM) data, and other associated measures, from the electronic medical records of 127 patients for the first 72 h of ICU care who upon admission to the ICU had a diagnosis of type 1 (n = 8) or type 2 diabetes (n = 97) or a glucose value >150 mg/dL (n = 22). A neural network-based model was developed to predict a complete trajectory of glucose values up to 135 min ahead of time. Model accuracy was validated using data from 15 of the 127 patients who were not included in the model training set to simulate model performance in real-world health care settings. Results: Predictive models achieved an improved accuracy and performance compared with previous models that were reported by our research team. Model error, expressed as mean absolute difference percent, was 10.6% with respect to interstitial glucose values (CGM) and 15.9% with respect to serum blood glucose values collected 135 min in the future. A Clarke Error Grid Analysis of model predictions with respect to the reference CGM and blood glucose measurements revealed that >99% of model predictions could be regarded as clinically acceptable and would not lead to inaccurate insulin therapy or treatment recommendations. Conclusion: The noted clinical acceptability of these models illustrates their potential utility within a clinical decision support system to assist health care providers in the optimization of glycemic management in critical care patients.

Comorbidity in adults with traumatic brain injury and all-cause mortality: a systematic review

OBJECTIVES

Comorbidity in traumatic brain injury (TBI) has been recognised to alter the clinical course of patients and influence short-term and long-term outcomes. We synthesised the evidence on the effects of different comorbid conditions on early and late mortality post-TBI in order to (1) examine the relationship between comorbid condition(s) and all-cause mortality in TBI and (2) determine the influence of sociodemographic and clinical characteristics of patients with a TBI at baseline on all-cause mortality.

DESIGN

Systematic review.

DATA SOURCES

Medline, Central, Embase, PsycINFO and bibliographies of identified articles were searched from May 1997 to January 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Included studies met the following criteria: (1) focused on comorbidity as it related to our outcome of interest in adults (ie, ≥18 years of age) diagnosed with a TBI; (2) comorbidity was detected by any means excluding self-report; (3) reported the proportion of participants without comorbidity and (4) followed participants for any period of time.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted the data and assessed risk of bias using the Quality in Prognosis Studies tool. Data were synthesised through tabulation and qualitative description.

RESULTS

A total of 27 cohort studies were included. Among the wide range of individual comorbid conditions studied, only low blood pressure was a consistent predictors of post-TBI mortality. Other consistent predictors were traditional sociodemographic risk factors. Higher comorbidity scale, scores and the number of comorbid conditions were not consistently associated with post-TBI mortality.

CONCLUSIONS

Given the high number of comorbid conditions that were examined by the single studies, research is required to further substantiate the evidence and address conflicting findings. Finally, an enhanced set of comorbidity measures that are suited for the TBI population will allow for better risk stratification to guide TBI management and treatment.

PROSPERO REGISTRATION NUMBER

CRD42017070033.

Modelling outcomes after paediatric brain injury with admission laboratory values: a machine-learning approach

BACKGROUND

Severe traumatic brain injury (TBI) is a leading cause of mortality in children, but the accurate prediction of outcomes at the point of admission remains very challenging. Admission laboratory results are a promising potential source of prognostic data, but have not been widely explored in paediatric cohorts. Herein, we use machine-learning methods to analyse 14 different serum parameters together and develop a prognostic model to predict 6-month outcomes in children with severe TBI.

METHODS

A retrospective review of patients admitted to Cambridge University Hospital's Paediatric Intensive Care Unit between 2009 and 2013 with a TBI. The data for 14 admission serum parameters were recorded. Logistic regression and a support vector machine (SVM) were trained with these data against dichotimised outcomes from the recorded 6-month Glasgow Outcome Scale.

RESULTS

Ninety-four patients were identified. Admission levels of lactate, H+, and glucose were identified as being the most informative of 6-month outcomes. Four different models were produced. The SVM using just the three most informative parameters was the best able to predict favourable outcomes at 6 months (sensitivity = 80%, specificity = 99%).

CONCLUSIONS

Our results demonstrate the potential for highly accurate outcome prediction after severe paediatric TBI using admission laboratory data.

Extended (10-Day) Real-Time Monitoring by Dexamethasone-Enhanced Microdialysis in the Injured Rat Cortex

Intracerebral microdialysis has proven useful for chemical monitoring in patients following traumatic brain injury. Recent studies in animals, however, have documented that insertion of microdialysis probes into brain tissues initiates a foreign-body response. Within a few days after probe insertion, the foreign body response impedes the use of microdialysis to monitor the K⁺ and glucose transients associated with spreading depolarization, a potential mechanism for secondary brain injury. Herein, we show that perfusing microdialysis probes with dexamethasone, a potent anti-inflammatory glucocorticoid, suppresses the foreign body response and facilitates the monitoring of spontaneous spreading depolarizations for at least 10 days following controlled cortical injury in the rat. In addition to spreading depolarizations, results of this study suggest that a progressive, apparently permanent, decline in pericontusional interstitial glucose may be an additional sequela of brain injury. This study establishes extended dexamethasone-enhanced microdialysis in the injured rodent cortex as a new paradigm for investigating trauma-induced metabolic crisis.

Making sense of gut feelings in the traumatic brain injury pathogenesis

Traumatic brain injury (TBI) is a devastating condition which often initiates a sequel of neurological disorders that can last throughout lifespan. From metabolic perspective, TBI also compromises systemic physiology including the function of body organs with subsequent malfunctions in metabolism. The emerging panorama is that the effects of TBI on the periphery strike back on the brain and exacerbate the overall TBI pathogenesis. An increasing number of clinical reports are alarming to show that metabolic dysfunction is associated with incidence of long-term neurological and psychiatric disorders. The autonomic nervous system, associated hypothalamic-pituitary axis, and the immune system are at the center of the interface between brain and body and are central to the regulation of overall homeostasis and disease. We review the strong association between mechanisms that regulate cell metabolism and inflammation which has important clinical implications for the communication between body and brain. We also discuss the integrative actions of lifestyle interventions such as diet and exercise on promoting brain and body health and cognition after TBI.

Early dysglycemia and mortality in traumatic brain injury and subarachnoid hemorrhage

BACKGROUND

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are the most common causes of severe acute brain injury in younger Intensive Care Unit (ICU) patients. Dysglycemia (abnormal peak glycemia, glycemic variability, mean glycemia, nadir glycemia) is common in these patients but its comparative outcome associations are unclear.

METHODS

In a retrospective, cross-sectional, study of adults admitted to Australian and New Zealand ICUs with TBI and SAH from 2005 to 2015, we studied the relationship between multiple aspects of early (first 24 hours) dysglycemia and mortality and compared TBI and SAH patients with the general ICU population and with each other.

RESULTS

Among 670,301 patients, 11,812 had TBI and 6,098 had SAH. After adjustment for illness severity, we found that the mortality rate increased with each quintile of glycemia for each aspect of early dysglycemia (peak glycemia, glycemic variability, mean glycemia, nadir glycemia; P<0.0001 for all). This increased risk of death was greater in TBI and SAH patients than in the general ICU population. Moreover, it was stronger for mean glycemia (increase in mortality from 9.2% in the lowest quintile to 15.1% in general ICU patients compared with an increase in mortality from 4.4% to 49.0% for TBI and SAH patients; P<0.0001). Finally, in TBI patients, this relationship was significantly stronger than in SAH patients (P<0.0001).

CONCLUSIONS

In TBI and SAH patients, greater dysglycemia is associated with greater mortality. This association is significantly stronger than in the general population and it is significantly stronger in patients with TBI compared with SAH.

Cerebral metabolic effects of strict versus conventional glycaemic targets following severe traumatic brain injury

Background

Optimal glycaemic targets for patients with severe traumatic brain injury remain unclear. The primary objective of this microdialysis study was to compare cerebral metabolism with strict versus conventional glycaemic control.

Methods

We performed a prospective single-centre randomised controlled within-subject crossover study of 20 adult patients admitted to an academic neurointensive care unit with severe traumatic brain injury. Patients underwent randomised, consecutive 24-h periods of strict (4–7 mmol/L; 72–126 mg/dl) and conventional (<10 mmol/L; 180 mg/dl) glycaemic control with microdialysis measurements performed hourly. The first 12 h of each study period was designated as a ‘washout’ period, with the subsequent 12 h being the period of interest.

Results

Cerebral glucose was lower during strict glycaemia than with conventional control (mean 1.05 [95% CI 0.58–1.51] mmol/L versus 1.28 [0.81–1.74] mmol/L; P = 0.03), as was lactate (3.07 [2.44–3.70] versus 3.56 [2.81–4.30]; P < 0.001). There were no significant differences in pyruvate or the lactate/pyruvate ratio between treatment phases. Strict glycaemia increased the frequency of low cerebral glucose (< 0.8 mmol/L; OR 1.91 [95% CI 1.01–3.65]; P < 0.05); however, there were no differences in the frequency of critically low glucose (< 0.2 mmol/L) or critically elevated lactate/pyruvate ratio between phases.

Conclusions

Compared with conventional glycaemic targets, strict blood glucose control was associated with lower mean levels of cerebral glucose and an increased frequency of abnormally low glucose levels. These data support conventional glycaemic targets following traumatic brain injury.

Trial registration

ISRCTN, ISRCTN19146279. Retrospectively registered on 2 May 2014.

Electronic supplementary material

The online version of this article (10.1186/s13054-017-1933-5) contains supplementary material, which is available to authorized users.

Glycaemic control targets after traumatic brain injury: a systematic review and meta-analysis

Background

Optimal glycaemic targets in traumatic brain injury (TBI) remain unclear. We performed a systematic review and meta-analysis of randomised controlled trials (RCTs) comparing intensive with conventional glycaemic control in TBI requiring admission to an intensive care unit (ICU).

Methods

We systematically searched MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials to November 2016. Outcomes of interest included ICU and in-hospital mortality, poor neurological outcome, the incidence of hypoglycaemia and infective complications. Data were analysed by pairwise random effects models with secondary analysis of differing levels of conventional glycaemic control.

Results

Ten RCTs, involving 1066 TBI patients were included. Three studies were conducted exclusively in a TBI population, whereas in seven trials, the TBI population was a sub-cohort of a mixed neurocritical or general ICU population. Glycaemic targets with intensive control ranged from 4.4 to 6.7 mmol/L, while conventional targets aimed to keep glucose levels below thresholds of 8.4–12 mmol/L. Conventional versus intensive control showed no association with ICU or hospital mortality (relative risk (RR) (95% CI) 0.93 (0.68–1.27), P = 0.64 and 1.07 (0.84–1.36), P = 0.62, respectively). The risk of a poor neurological outcome was higher with conventional control (RR (95% CI) = 1.10 (1.001–1.24), P = 0.047). However, severe hypoglycaemia occurred less frequently with conventional control (RR (95% CI) = 0.22 (0.09–0.52), P = 0.001).

Conclusions

This meta-analysis of intensive glycaemic control shows no association with reduced mortality in TBI. Intensive glucose control showed a borderline significant reduction in the risk of poor neurological outcome, but markedly increased the risk of hypoglycaemia. These contradictory findings should motivate further research.

Electronic supplementary material

The online version of this article (10.1186/s13054-017-1883-y) contains supplementary material, which is available to authorized users.

Management of severe traumatic brain injury (first 24hours)

The latest French Guidelines for the management in the first 24hours of patients with severe traumatic brain injury (TBI) were published in 1998. Due to recent changes (intracerebral monitoring, cerebral perfusion pressure management, treatment of raised intracranial pressure), an update was required. Our objective has been to specify the significant developments since 1998. These guidelines were conducted by a group of experts for the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie et de réanimation [SFAR]) in partnership with the Association de neuro-anesthésie-réanimation de langue française (ANARLF), The French Society of Emergency Medicine (Société française de médecine d'urgence (SFMU), the Société française de neurochirurgie (SFN), the Groupe francophone de réanimation et d'urgences pédiatriques (GFRUP) and the Association des anesthésistes-réanimateurs pédiatriques d'expression française (ADARPEF). The method used to elaborate these guidelines was the Grade^® method. After two Delphi rounds, 32 recommendations were formally developed by the experts focusing on the evaluation the initial severity of traumatic brain injury, the modalities of prehospital management, imaging strategies, indications for neurosurgical interventions, sedation and analgesia, indications and modalities of cerebral monitoring, medical management of raised intracranial pressure, management of multiple trauma with severe traumatic brain injury, detection and prevention of post-traumatic epilepsia, biological homeostasis (osmolarity, glycaemia, adrenal axis) and paediatric specificities.

Severe Intraoperative Hyperglycemia Is Independently Associated With Postoperative Composite Infection After Craniotomy: An Observational Study

BACKGROUND

Postoperative infection after craniotomy carries an increased risk of morbidity and mortality. Identification and correction of the risk factors should be prioritized. The association of intraoperative hyperglycemia with postoperative infections in patients undergoing craniotomy is inadequately studied.

METHODS

A total of 224 patients were prospectively enrolled in 2 major medical centers to assess whether severe intraoperative hyperglycemia (SIH, blood glucose ≥180 mg/dL) is associated with an increased risk of postoperative infection in patients undergoing craniotomy. Arterial blood samples were drawn and analyzed immediately after anesthetic induction and again before tracheal extubation. The new onset of any type of infection within 7 days after craniotomy was determined.

RESULTS

The incidence of new postoperative composite infection was 10% (n = 22) within the first week after craniotomy. Weight, sex, American Society of Anesthesiologists score, preoperative and/or intraoperative steroid use, and diabetes mellitus were not associated with postoperative infection. SIH was independently associated with postoperative infection (odds ratio [95% confidence interval], 4.17 [1.50-11.56], P = .006) after fitting a multiple logistic regression model to adjust for emergency surgery, length of surgery, and age ≥65 years.

CONCLUSIONS

SIH is independently associated with postoperative new-onset composite infections in patients undergoing craniotomy. Whether prevention of SIH during craniotomy results in a reduced postoperative risk of infection is unknown and needs to be appraised by further study.

7,8-Dihydroxyflavone facilitates the action exercise to restore plasticity and functionality: Implications for early brain trauma recovery

Metabolic dysfunction accompanying traumatic brain injury (TBI) severely impairs the ability of injured neurons to comply with functional demands. This limits the success of rehabilitative strategies by compromising brain plasticity and function, and highlights the need for early interventions to promote energy homeostasis. We sought to examine whether the TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF) normalizes brain energy deficits and reestablishes more normal patterns of functional connectivity, while enhancing the effects of exercise during post-TBI period. Moderate fluid percussion injury (FPI) was performed and 7,8-DHF (5mg/kg, i.p.) was administered in animals subjected to FPI that either had access to voluntary wheel running for 7days after injury or were sedentary. Compared to sham-injured controls, TBI resulted in reduced hippocampal activation of the BDNF receptor TrkB and associated CREB, reduced levels of plasticity markers GAP-43 and Syn I, as well as impaired memory as indicated by the Barnes maze task. While 7,8-DHF treatment and exercise individually mitigated TBI-induced effects, administration of 7,8-DHF concurrently with exercise facilitated memory performance and augmented levels of markers of cell energy metabolism viz., PGC-1α, COII and AMPK. In parallel to these findings, resting-state functional MRI (fMRI) acquired at 2weeks after injury showed that 7,8-DHF with exercise enhanced hippocampal functional connectivity, and suggests 7,8-DHF and exercise to promote increases in functional connectivity. Together, these findings indicate that post-injury 7,8-DHF treatment promotes enhanced levels of cell metabolism, synaptic plasticity in combination with exercise increases in brain circuit function that facilitates greater physical rehabilitation after TBI.

Radiologic Findings and Patient Factors Associated with 30-Day Mortality after Surgical Evacuation of Subdural Hematoma in Patients Less Than 65 Years Old

Objective

The purpose of this study is to evaluate the associations between 30-day mortality and various radiological and clinical factors in patients with traumatic acute subdural hematoma (SDH). During the 11-year study period, young patients who underwent surgery for SDH were followed for 30 days. Patients who died due to other medical comorbidities or other organ problems were not included in the study population.

Methods

From January 1, 2004 to December 31, 2014, 318 consecutive surgically-treated traumatic acute SDH patients were registered for the study. The Kaplan–Meier method was used to analyze 30-day survival rates. We also estimated the hazard ratios of various variables in order to identify the independent predictors of 30-day mortality.

Results

We observed a negative correlation between 30-day mortality and Glasgow coma scale score (per 1-point score increase) (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.52–0.70; p<0.001). In addition, use of antithrombotics (HR, 2.34; 95% CI, 1.27–4.33; p=0.008), history of diabetes mellitus (HR, 2.28; 95% CI, 1.20–4.32; p=0.015), and accompanying traumatic subarachnoid hemorrhage (hazard ratio, 2.13; 95% CI, 1.27–3.58; p=0.005) were positively associated with 30-day mortality.

Conclusion

We found significant associations between short-term mortality after surgery for traumatic acute SDH and lower Glasgow Coma Scale scores, use of antithrombotics, history of diabetes mellitus, and accompanying traumatic subarachnoid hemorrhage at admission. We expect these findings to be helpful for selecting patients for surgical treatment of traumatic acute SDH, and for making accurate prognoses.

The impact of early hyperglycaemia on children with traumatic brain injury

OBJECTIVE

Hyperglycaemia is common amongst children with traumatic brain injury (TBI). We aim to investigate the association between early hyperglycaemia and poor clinical outcomes in children with moderate to severe TBI.

METHODS

We performed a retrospective study in a tertiary paediatric hospital between May 2012 and October 2014 of all patients with TBI who were aged <16 years with a Glasgow Coma Scale (GCS) of ≤13. The primary outcome was death. Secondary outcomes were 14 ventilation-free, 14 paediatric intensive care unit (PICU)-free and 28 hospital-free days. We defined hyperglycaemia as glucose >11.1 mmol/L (200 mg/dL).

RESULTS

There were 109 patients with a median age of 54 months [inter-quartile range (IQR): 17-82]. Median glucose on arrival was 6.1 mmol/L (IQR: 5.2-9.8). Median GCS in our cohort was 8 (IQR: 6-12). Multivariate logistic regression demonstrated that initial hyperglycaemia [odds ratio (OR): 15.23; 95% confidence interval (CI): 3.74-62.00; P < 0.001], and GCS <8 (OR: 13.02; 95% CI: 2.31-73.33; P = 0.004) were risk factors for mortality. Multivariate linear regression showed that initial hyperglycaemia was a risk factor for reduced ventilation-free, PICU-free and hospital-free days.

CONCLUSIONS

Early hyperglycaemia predicts for in-hospital mortality, reduced ventilation-free, PICU-free and hospital-free days in children with moderate to severe TBI.

Clinical Outcomes after Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of death and disability that often affects young people. After injury, the degree of recovery can be highly variable, with some people regaining near complete function while others remain severely disabled. Understanding what factors influence recovery is important for counseling patients and families in the acute period after injury and can help guide therapeutic decisions in the acute period following injury. In this review, prognostic algorithms useful for clinicians are discussed. Tools for grading patient outcomes, their role in clinical care and research studies, and their limitations are reviewed. Ongoing work focusing on the development of biomarkers to track TBI recovery and the refinement of clinical outcome metrics is summarized.

Age and Diet Affect Genetically Separable Secondary Injuries that Cause Acute Mortality Following Traumatic Brain Injury in Drosophila

Outcomes of traumatic brain injury (TBI) vary because of differences in primary and secondary injuries. Primary injuries occur at the time of a traumatic event, whereas secondary injuries occur later as a result of cellular and molecular events activated in the brain and other tissues by primary injuries. We used a Drosophila melanogaster TBI model to investigate secondary injuries that cause acute mortality. By analyzing mortality percentage within 24 hr of primary injuries, we previously found that age at the time of primary injuries and diet afterward affect the severity of secondary injuries. Here, we show that secondary injuries peaked in activity 1–8 hr after primary injuries. Additionally, we demonstrate that age and diet activated distinct secondary injuries in a genotype-specific manner, and that concurrent activation of age- and diet-regulated secondary injuries synergistically increased mortality. To identify genes involved in secondary injuries that cause mortality, we compared genome-wide mRNA expression profiles of uninjured and injured flies under age and diet conditions that had different mortalities. During the peak period of secondary injuries, innate immune response genes were the predominant class of genes that changed expression. Furthermore, age and diet affected the magnitude of the change in expression of some innate immune response genes, suggesting roles for these genes in inhibiting secondary injuries that cause mortality. Our results indicate that the complexity of TBI outcomes is due in part to distinct, genetically controlled, age- and diet-regulated mechanisms that promote secondary injuries and that involve a subset of innate immune response genes.

Diffuse Axonal Injury: Epidemiology, Outcome and Associated Risk Factors

Diffuse axonal injury (DAI), a type of traumatic injury, is known for its severe consequences. However, there are few studies describing the outcomes of DAI and the risk factors associated with it. This study aimed to describe the outcome for patients with a primary diagnosis of DAI 6 months after trauma and to identify sociodemographic and clinical factors associated with mortality and dependence at this time point. Seventy-eight patients with DAI were recruited from July 2013 to February 2014 in a prospective cohort study. Patient outcome was analyzed using the Extended Glasgow Outcome Scale (GOS-E) within 6 months of the traumatic injury. The mean Injury Severity Score was 35.0 (SD = 11.9), and the mean New Injury Severity Score (NISS) was 46.2 (SD = 15.9). Mild DAI was observed in 44.9% of the patients and severe DAI in 35.9%. Six months after trauma, 30.8% of the patients had died, and 45.1% had shown full recovery according to the GOS-E. In the logistic regression model, the severity variables - DAI with hypoxia, as measured by peripheral oxygen saturation, and hypotension with NISS value - had a statistically significant association with patient mortality; on the other hand, severity of DAI and length of hospital stay were the only significant predictors for dependence. Therefore, severity of DAI emerged as a risk factor for both mortality and dependence.

Influence of two anesthetic techniques on blood sugar level in head injury patients: A comparative study

BACKGROUND

Head injury presents a major worldwide social, economic, and health problem. Hyperglycemia is a significant indicator of the severity of injury and predictor of outcome, which can easily be prevented. There has been a long-standing controversy regarding the use of inhalational or intravenous (i.v.) anesthetic agents for surgery of head injury cases and impact of these agents on blood sugar level.

AIMS AND OBJECTIVES

The aim of this study is to find out anesthetic drugs and technique having minimal or no effect on the blood sugar, and Glasgow Coma Scale (GCS) of patients with a head injury by comparing two types of anesthetic techniques in surgery of head injury patients.

MATERIALS AND METHODS

This was a prospective, randomized, and comparative study, conducted on 60 adult head injury patients. The patients were divided into two groups of 30 each. Group I patients received induction with sevoflurane and then had O2 + air + sevoflurane for maintenance with controlled ventilation. Group II patients received induction with i.v. propofol and then had O2 + air + propofol for maintenance with controlled ventilation. Injection fentanyl was used in both the groups at the time of induction and in intermittent boluses in maintenance. In observation, blood sugar level and mean arterial pressure were assessed at different time periods perioperatively in both groups while GCS was analyzed pre- and post-operatively.

STATISTICAL ANALYSIS

Statistical analysis was performed by Microsoft Excel 2010 using t-test for comparison between the two groups and Z-test for comparison of proportions.

RESULTS AND CONCLUSION

Blood sugar level was found significantly higher in patients of sevoflurane group at 30 min after induction, at the end of surgery, and 1 h after the end of anesthesia than propofol group patients. This increase of blood sugar level did not have any significant alteration in the GCS profile of the patients in sevoflurane group as compared to propofol group patients. Nausea and vomiting were found more in sevoflurane group while hypotension and bradycardia were found more with propofol group.

Dietary fructose aggravates the pathobiology of traumatic brain injury by influencing energy homeostasis and plasticity

Fructose consumption has been on the rise for the last two decades and is starting to be recognized as being responsible for metabolic diseases. Metabolic disorders pose a particular threat for brain conditions characterized by energy dysfunction, such as traumatic brain injury. Traumatic brain injury patients experience sudden abnormalities in the control of brain metabolism and cognitive function, which may worsen the prospect of brain plasticity and function. The mechanisms involved are poorly understood. Here we report that fructose consumption disrupts hippocampal energy homeostasis as evidenced by a decline in functional mitochondria bioenergetics (oxygen consumption rate and cytochrome C oxidase activity) and an aggravation of the effects of traumatic brain injury on molecular systems engaged in cell energy homeostasis (sirtuin 1, peroxisome proliferator-activated receptor gamma coactivator-1alpha) and synaptic plasticity (brain-derived neurotrophic factor, tropomyosin receptor kinase B, cyclic adenosine monophosphate response element binding, synaptophysin signaling). Fructose also worsened the effects of traumatic brain injury on spatial memory, which disruption was associated with a decrease in hippocampal insulin receptor signaling. Additionally, fructose consumption and traumatic brain injury promoted plasma membrane lipid peroxidation, measured by elevated protein and phenotypic expression of 4-hydroxynonenal. These data imply that high fructose consumption exacerbates the pathology of brain trauma by further disrupting energy metabolism and brain plasticity, highlighting the impact of diet on the resilience to neurological disorders.

Hyperglycemia is a predictor of prognosis in traumatic brain injury: Tertiary intensive care unit study

Background:

Hyperglycemia is frequently encountered in critically ill patients and has been shown to contribute to both morbidity and mortality. We aimed to study the predictive role of blood glucose level in clinical outcomes of mechanically ventilated patients with traumatic brain injury during intensive care unit (ICU) stay and to explore its relationship with Glasgow coma scale (GCS) and acute physiology and chronic health examination (APACHE) II scores that are used in the evaluation of ICU patients as predictor.

Materials and Methods:

A total of 185 patients with craniocerebral trauma who were hospitalized in the ICU were included in the study. Comparisons of mean glucose values (MGVs) and APACHE II scores between survivors and nonsurvivors were made with Student's t-test and chi-square test. Survival analysis was performed with log rank (Mantel-Cox) test and Cox regression was used for mortality risk factors analysis.

Results:

MGVs at the initial, last, and all measurements were significantly higher for nonsurvivors than for survivors. Hazard rate at any given time point for patients with mean glucose value (MGV) between 150 and 179 was found to be 3.691 times that of patients with MGV values between 110 and 149. The hazard rate at any given time point for patients with MGV values ≥180 was found to be 6.571 times that of patients with MGV values between 110 and 149.

Conclusion:

High glucose level is an independent risk factor for mortality in mechanically ventilated ICU patients with traumatic brain injury.

Stress-induced hyperglycemia is associated with higher mortality in severe traumatic brain injury

BACKGROUND

An association between stress-induced hyperglycemia (SIH) and increased mortality has been demonstrated following trauma. Experimental animal model data regarding the association between hyperglycemia and outcomes following traumatic brain injury (TBI) are inconsistent, suggesting that hyperglycemia may be harmful, neutral, or beneficial. The purpose of this study was to examine the effects of SIH versus diabetic hyperglycemia (DH) on severe TBI.

METHODS

Admission glycosylated hemoglobin (HbA1c), glucose levels, and comorbidity data were collected during a 4-year period from September 2009 to December 2013 for patients with severe TBI (i.e., admission Glasgow Coma Scale [GCS] score of 3-8 and head Abbreviated Injury Scale [AIS] score ≥ 3). Diabetes mellitus was determined by patient history or admission HbA1c of 6.5% or greater. SIH was determined by the absence of diabetes mellitus and admission glucose of 200 mg/dL or greater. A Cox proportional hazards model adjusted for age, sex, injury mechanism, and Injury Severity Score (ISS) was used to calculate hazard ratios (HRs) and associated 95% confidence intervals (CIs) for the association between SIH and the outcomes of interest.

RESULTS

During the study period, a total of 626 patients were included in the study group, having severe TBI defined by both GCS score of 3 to 8 and head AIS score being 3 or greater and also had available HbA1c and admission glucose levels. A total of 184 patients were admitted with hyperglycemia; 152 patients (82.6%) were diagnosed with SIH, and 32 patients (17.4%) were diagnosed with DH. When comparing patients with severe TBI adjusted for age, sex, injury mechanism, ISS, Revised Trauma Score (RTS), and lactic acid greater than 2.5 mmol/L, patients with SIH had a 50% increased mortality (HR, 1.49; 95% CI, 1.13-1.95) compared with the nondiabetic normoglycemia patients. DH patients did not have a significant increase in mortality (HR, 0.94; 95% CI, 0.56-1.58).

CONCLUSION

SIH is associated with higher mortality after severe TBI. This association was not observed among patients with DH, which suggests that hyperglycemia related to diabetes is of less importance compared with SIH in terms of mortality in the acute trauma and TBI patient. Further research is warranted to identify mechanisms causing SIH and subsequent worse outcomes after TBI.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, leve III.

Intensive versus conventional glucose control in critically ill patients with traumatic brain injury: long-term follow-up of a subgroup of patients from the NICE-SUGAR study

PURPOSE

To compare the effect of intensive versus conventional blood glucose control in patients with traumatic brain injury.

METHODS

In a large international randomized trial patients were randomly assigned to a target blood glucose (BG) range of either 4.5-6.0 mmol/L (intensive control) or <10 mmol/L (conventional control). Patients with traumatic brain injury (TBI) were identified at randomization and data were collected to examine the extended Glasgow outcome score (includes mortality) at 24 months.

RESULTS

Of the 6104 randomized patients, 391 satisfied diagnostic criteria for TBI; 203 (51.9%) were assigned to intensive and 188 (48.1%) to conventional control; the primary outcome was available for 166 (81.8%) and 149 (79.3%) patients, respectively. The two groups had similar baseline characteristics. At 2 years 98 (58.7%) patients in the intensive group and 79 (53.0%) in the conventional group had a favorable neurological outcome (odds ratio [OR] 1.26, 95% CI 0.81-1.97; P = 0.3); 35 patients (20.9%) in the intensive group and 34 (22.8%) in the conventional group had died (OR 0.90, 95% CI 0.53-1.53; P = 0.7); moderate hypoglycemia (BG 2.3-3.9 mmol/L; 41-70 mg/dL) occurred in 160/202 (79.2%) and 17/188 (9.0%), respectively (OR 38.3, 95% CI 21.0-70.1; P < 0.0001); severe hypoglycemia (BG ≤ 2.2 mmol/L; ≤40 mg/dL) in 10 (4.9%) and 0 (0.0%), respectively (OR 20.5 95% CI 1.2-351.6, P = 0.003).

CONCLUSION

Although patients with traumatic brain injury randomly assigned to intensive compared to conventional glucose control experienced moderate and severe hypoglycemia more frequently, we found no significant difference in clinically important outcomes.

Perioperative glycemic status of adult traumatic brain injury patients undergoing craniotomy: a prospective observational study

BACKGROUND

Patients of traumatic brain injury (TBI) may have hyperglycemia and when they undergo craniotomy, hyperglycemia may be exacerbated and worsen outcome. However, epidemiology of perioperative hyperglycemia in these patients is unknown. The epidemiological study has been undertaken to address the correlation between intraoperative blood glucose variability in nondiabetic adult TBI patients undergoing craniotomy with the severity and type of brain trauma and patients' demographic variables.

METHODS

A total of 200 adult nondiabetic patients undergoing emergency craniotomy for TBI were recruited in this prospective single-group observational study. Baseline capillary blood glucose (CBG) measurement was performed immediately before induction of anesthesia and then at half hourly interval until the end of surgery and 1 hour after the end of surgery.

RESULTS

Incidence of at least 1 episode of intraoperative hyperglycemia (CBG≥180 mg/dL) is 20% in patients with TBI during emergency craniotomy. Independent predictors of intraoperative hyperglycemia are severe head injury (Glasgow-Coma score [GCS] <9) and acute subdural hemorrhage. Baseline CBG also correlates with subsequent intraoperative and postoperative CBG.

CONCLUSIONS

Hyperglycemia is common during emergency craniotomy in TBI patients. We recommend routine monitoring of blood glucose in the intraoperative and postoperative period at least in severe head injury patients.

Glucose administration after traumatic brain injury exerts some benefits and no adverse effects on behavioral and histological outcomes

The impact of hyperglycemia after traumatic brain injury (TBI), and even the administration of glucose-containing solutions to head injured patients, remains controversial. In the current study adult male Sprague-Dawley rats were tested on behavioral tasks and then underwent surgery to induce sham injury or unilateral controlled cortical impact (CCI) injury followed by injections (i.p.) with either a 50% glucose solution (Glc; 2g/kg) or an equivalent volume of either 0.9% or 8% saline (Sal) at 0, 1, 3 and 6h post-injury. The type of saline treatment did not significantly affect any outcome measures, so these data were combined. Rats with CCI had significant deficits in beam-walking traversal time and rating scores (p's < 0.001 versus sham) that recovered over test sessions from 1 to 13 days post-injury (p's < 0.001), but these beam-walking deficits were not affected by Glc versus Sal treatments. Persistent post-CCI deficits in forelimb contraflexion scores and forelimb tactile placing ability were also not differentially affected by Glc or Sal treatments. However, deficits in latency to retract the right hind limb after limb extension were significantly attenuated in the CCI-Glc group (p < 0.05 versus CCI-Sal). Both CCI groups were significantly impaired in a plus maze test of spatial working memory on days 4, 9 and 14 post-surgery (p < 0.001 versus sham), and there was no effect of Glc versus Sal on this cognitive outcome measure. At 15 days post-surgery the loss of cortical tissue volume (p < 0.001 versus sham) was significantly less in the CCI-Glc group (30.0%; p < 0.05) compared to the CCI-Sal group (35.7%). Counts of surviving hippocampal hilar neurons revealed a significant (~40%) loss ipsilateral to CCI (p < 0.001 versus sham), but neuronal loss in the hippocampus was not different in the CCI-Sal and CCI-Glc groups. Taken together, these results indicate that an early elevation of blood glucose may improve some neurological outcomes and, importantly, the induction of hyperglycemia after isolated TBI did not adversely affect any sensorimotor, cognitive or histological outcomes.

Continuous measurement of the cumulative amplitude and duration of hyperglycemia best predicts outcome after traumatic brain injury

BACKGROUND

This study aimed to assess the accuracy and utility of high-resolution continuous glucose recording in patients with traumatic brain injury (TBI) and to establish whether a relationship exists between the cumulative amplitude and duration of hyperglycemia and outcome after TBI.

METHODS

Glucose data for 56 TBI patients were collected continuously at 5-min intervals. The degree and duration of hyperglycemia above treatment thresholds were calculated as "glucose times time dose" (GTD; mg/dL d) using continuous recordings (GTD) for early stage (first 3 days). Long-term neurological functional outcome was assessed using the extended Glasgow Outcome Scale (GOSE). Receiver operating characteristic (ROC) curves were constructed to determine the predictive values of GTD, percentage readings, mean, and range of glucose for in-hospital mortality and GOSE.

RESULTS

All measurements of GTD were statistically significantly higher in the group that died. GTD of glucose >150 and glucose >180 had a high-predictive power for in-hospital mortality (areas under the ROC curve [AUC] = 0.917; 95 % CI, 0.837-0.998 and 0.876; 95 % CI, 0.784-0.967, respectively) and demonstrated significantly higher predictive power for mortality when compared with %reading >150 and %reading >180, respectively (p < 0.05). GTD of glucose >150 also had a significantly higher predictive power for mortality than mean glucose and range of glucose. GTD of glucose >150 and glucose >180 also had a high-predictive power for poor outcome (areas under the ROC curve [AUC] = 0.913; 95 % CI, 0.843-0.983 and 0.858; 95 % CI, 0.760-0.956, respectively).

CONCLUSIONS

Continuous collection of glucose recordings is more reliable and accurate than routine discontinuous recordings. Assessing both the duration and the amplitude of the episodes using continuous collection of glucose data helps in better predicting outcomes than the total duration of episodes.

Flavonoid derivative 7,8-DHF attenuates TBI pathology via TrkB activation

Traumatic brain injury (TBI) is followed by a state of metabolic dysfunction, affecting the ability of neurons to use energy and support brain plasticity; there is no effective therapy to counteract the TBI pathology. Brain-derived neurotrophic factor (BDNF) has an exceptional capacity to support metabolism and plasticity, which highly contrasts with its poor pharmacological profile. We evaluated the action of a flavonoid derivative 7,8-dihydroxyflavone (7,8-DHF), a BDNF receptor (TrkB) agonist with the pharmacological profile congruent for potential human therapies. Treatment with 7,8-DHF (5mg/kg, ip, daily for 7 days) was effective to ameliorate the effects of TBI on plasticity markers (CREB phosphorylation, GAP-43 and syntaxin-3 levels) and memory function in Barnes maze test. Treatment with 7,8-DHF restored the decrease in protein and phenotypic expression of TrkB phosphorylation after TBI. In turn, intrahippocampal injections of K252a, a TrkB antagonist, counteracted the 7,8-DHF induced TrkB signaling activation and memory improvement in TBI, suggesting the pivotal role of TrkB signaling in cognitive performance after brain injury. A potential action of 7,8-DHF on cell energy homeostasis was corroborated by the normalization in levels of PGC-1α, TFAM, COII, AMPK and SIRT1 in animals subjected to TBI. Results suggest a potential mechanism by which 7,8-DHF counteracts TBI pathology via activation of the TrkB receptor and engaging the interplay between cell energy management and synaptic plasticity. Since metabolic dysfunction is an important risk factor for the development of neurological and psychiatric disorders, these results set a precedent for the therapeutic use of 7,8-DHF in a larger context.

Treatment of endocrine disorders in the neuroscience intensive care unit

OPINION STATEMENT

This review discusses concepts and treatments associated with the most clinically relevant areas of acute endocrine dysfunction amongst patients with common diseases in neuroscience intensive care units (Neuro ICUs). We highlight the following points:• While a thorough work-up for hyponatremia when it is present is always warranted, subarachnoid hemorrhage (SAH) patients who are in a time window concerning for cerebral vasospasm and who are hyponatremic with high urine output are generally thought to have cerebral salt wasting. These patients are typically treated with a combination of continuous hypertonic saline infusion and fludrocortisone.• Diabetes insipidus (DI) is often seen in patients fulfilling death by neurological criteria, as well as in patients with recent pituitary surgery and less often in SAH and traumatic brain injury patients who are not brain dead. Patients with DI in the Neuro ICU often cannot drink to thirst and may require a combination of desmopression/vasopressin administration, aggressive fluid repletion, and serum sodium monitoring.• Diagnosing adrenal insufficiency immediately following pituitary injury is complicated by the fact that the expected atrophy of the adrenal glands, due to lack of a stimulus from pituitary adrenocorticotropic hormone, may take up to 6 weeks to develop. Cosyntropin testing can be falsely normal during this period.• Both hyperglycemia (glucose >200 mg/dL) and hypoglycemia (glucose <50 mg/dL) are strongly associated with neurological morbidity and mortality in ICUs and should be avoided. Glucose concentrations between 120-160 mg/dL can serve as a reasonable target for insulin infusion protocols.• There is no data to suggest that treatment of abnormal thyroid function tests in nonthyroidal illness syndrome/sick euthyroid leads to benefits in either mortality or morbidity. True myxedema coma is a rare clinical diagnosis that is treated with intravenous levothyroxine accompanied by stress-dose steroids.

Glucose administration after traumatic brain injury improves cerebral metabolism and reduces secondary neuronal injury

Clinical studies have indicated an association between acute hyperglycemia and poor outcomes in patients with traumatic brain injury (TBI), although optimal blood glucose levels needed to maximize outcomes for these patients' remain under investigation. Previous results from experimental animal models suggest that post-TBI hyperglycemia may be harmful, neutral, or beneficial. The current studies determined the effects of single or multiple episodes of acute hyperglycemia on cerebral glucose metabolism and neuronal injury in a rodent model of unilateral controlled cortical impact (CCI) injury. In Experiment 1, a single episode of hyperglycemia (50% glucose at 2 g/kg, i.p.) initiated immediately after CCI was found to significantly attenuate a TBI-induced depression of glucose metabolism in cerebral cortex (4 of 6 regions) and subcortical regions (2 of 7) as well as to significantly reduce the number of dead/dying neurons in cortex and hippocampus at 24 h post-CCI. Experiment 2 examined effects of more prolonged and intermittent hyperglycemia induced by glucose administrations (2 g/kg, i.p.) at 0, 1, 3 and 6h post-CCI. The latter study also found significantly improved cerebral metabolism (in 3 of 6 cortical and 3 of 7 subcortical regions) and significant neuroprotection in cortex and hippocampus 1 day after CCI and glucose administration. These results indicate that acute episodes of post-TBI hyperglycemia can be beneficial and are consistent with other recent studies showing benefits of providing exogenous energy substrates during periods of increased cerebral metabolic demand.

Perioperative management of traumatic brain injury

Traumatic brain injury (TBI) is a major public health problem and the leading cause of death and disability worldwide. Despite the modern diagnosis and treatment, the prognosis for patients with TBI remains poor. While severity of primary injury is the major factor determining the outcomes, the secondary injury caused by physiological insults such as hypotension, hypoxemia, hypercarbia, hypocarbia, hyperglycemia and hypoglycemia, etc. that develop over time after the onset of the initial injury, causes further damage to brain tissue, worsening the outcome in TBI. Perioperative period may be particularly important in the course of TBI management. While surgery and anesthesia may predispose the patients to new onset secondary injuries which may contribute adversely to outcomes, the perioperative period is also an opportunity to detect and correct the undiagnosed pre-existing secondary insults, to prevent against new secondary insults and is a potential window to initiate interventions that may improve outcome of TBI. For this review, extensive Pubmed and Medline search on various aspects of perioperative management of TBI was performed, followed by review of research focusing on intraoperative and perioperative period. While the research focusing specifically on the intraoperative and immediate perioperative TBI management is limited, clinical management continues to be based largely on physiological optimization and recommendations of Brain Trauma Foundation guidelines. This review is focused on the perioperative management of TBI, with particular emphasis on recent developments.

Multivariate outcome prediction in traumatic brain injury with focus on laboratory values

Traumatic brain injury (TBI) is a major cause of morbidity and mortality. Identifying factors relevant to outcome can provide a better understanding of TBI pathophysiology, in addition to aiding prognostication. Many common laboratory variables have been related to outcome but may not be independent predictors in a multivariate setting. In this study, 757 patients were identified in the Karolinska TBI database who had retrievable early laboratory variables. These were analyzed towards a dichotomized Glasgow Outcome Scale (GOS) with logistic regression and relevance vector machines, a non-linear machine learning method, univariately and controlled for the known important predictors in TBI outcome: age, Glasgow Coma Score (GCS), pupil response, and computed tomography (CT) score. Accuracy was assessed with Nagelkerke's pseudo R². Of the 18 investigated laboratory variables, 15 were found significant (p<0.05) towards outcome in univariate analyses. In contrast, when adjusting for other predictors, few remained significant. Creatinine was found an independent predictor of TBI outcome. Glucose, albumin, and osmolarity levels were also identified as predictors, depending on analysis method. A worse outcome related to increasing osmolarity may warrant further study. Importantly, hemoglobin was not found significant when adjusted for post-resuscitation GCS as opposed to an admission GCS, and timing of GCS can thus have a major impact on conclusions. In total, laboratory variables added an additional 1.3-4.4% to pseudo R².

Optimal glycemic control in neurocritical care patients: a systematic review and meta-analysis

INTRODUCTION

Hyper- and hypoglycemia are strongly associated with adverse outcomes in critical care. Neurologically injured patients are a unique subgroup, where optimal glycemic targets may differ, such that the findings of clinical trials involving heterogeneous critically ill patients may not apply.

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing intensive insulin therapy with conventional glycemic control among patients with traumatic brain injury, ischemic or hemorrhagic stroke, anoxic encephalopathy, central nervous system infections or spinal cord injury.

RESULTS

Sixteen RCTs, involving 1248 neurocritical care patients, were included. Glycemic targets with intensive insulin ranged from 70-140 mg/dl (3.9-7.8 mmol/L), while conventional protocols aimed to keep glucose levels below 144-300 mg/dl (8.0-16.7 mmol/L). Tight glycemic control had no impact on mortality (RR 0.99; 95% CI 0.83-1.17; p = 0.88), but did result in fewer unfavorable neurological outcomes (RR 0.91; 95% CI 0.84-1.00; p = 0.04). However, improved outcomes were only observed when glucose levels in the conventional glycemic control group were permitted to be relatively high [threshold for insulin administration > 200 mg/dl (> 11.1 mmol/L)], but not with more intermediate glycemic targets [threshold for insulin administration 140-180 mg/dl (7.8-10.0 mmol/L)]. Hypoglycemia was far more common with intensive therapy (RR 3.10; 95% CI 1.54-6.23; p = 0.002), but there was a large degree of heterogeneity in the results of individual trials (Q = 47.9; p<0.0001; I2 = 75%). Mortality was non-significantly higher with intensive insulin in studies where the proportion of patients developing hypoglycemia was large (> 33%) (RR 1.17; 95% CI 0.79-1.75; p = 0.44).

CONCLUSIONS

Intensive insulin therapy significantly increases the risk of hypoglycemia and does not influence mortality among neurocritical care patients. Very loose glucose control is associated with worse neurological recovery and should be avoided. These results suggest that intermediate glycemic goals may be most appropriate.

Association of persistent hyperglycemia with outcome of severe traumatic brain injury in pediatric population

PURPOSE

Hyperglycemia is a common secondary insult associated with an increased risk of mortality and poor outcome in traumatic brain injury (TBI), but the effect of hyperglycemia on outcomes of severe TBI in children and adolescents is less apparent. The aim of this study was to evaluate the association of hyperglycemia with mortality in pediatric patients with severe TBI.

METHODS

In this cross-sectional study, data of all children and adolescents with severe TBI admitted to Poursina Hospital in Rasht, including age, gender, Glasgow Coma Scale (GCS) upon admission, mortality rate, hospital length of stay, and serial blood glucose during the first three consecutive ICU days following admission, were reviewed from April 2007 to May 2011. After univariate analysis and adjustment for related covariates, logistic regression model was established to determine the association between persistent hyperglycemia and outcome.

RESULTS

One-hundred and twenty-two children were included with a median admission GCS of 6 (interquartile range (IQR) 5-7) and a median age of 13 years (IQR 7.75-17). Among them, 91 were boys (74.6%) and 31 were girls (26.6%); the overall mortality was 40.2% (n=49). Patients who died had a significantly greater blood glucose levels than survivors for the first 3 days of admission (P=0.003, P<0.001, P=0.001, respectively). Moreover, persistent hyperglycemia during the first 3 days of admission had an adjusted odds ratio of 11.11 for mortality (P<0.001).

CONCLUSION

Early hyperglycemia is associated with poor outcome, and persistent hyperglycemia is a powerful and independent predictor of mortality in children and adolescents with severe TBI.

Perioperative management of adult traumatic brain injury

This article presents an overview of the management of traumatic brain injury (TBI) as relevant to the practicing anesthesiologist. Key concepts surrounding the pathophysiology and anesthetic principles are used to describe potential ways to reduce secondary insults and improve outcomes after TBI.

Spontaneous subarachnoid hemorrhage and glucose management

Although metabolic abnormalities have been linked with poor outcome after subarachnoid hemorrhage, there are limited data addressing the impact of glycemic control or benefits of glucose management after aneurysmal subarachnoid hemorrhage. A systematic literature search was conducted of English-language articles describing original research on glycemic control in patients with subarachnoid hemorrhage. Case reports and case series were excluded. A total of 22 publications were selected for this review. Among the 17 studies investigating glucose as an outcome predictor, glucose levels during hospitalization were more likely to predict outcome than admission glucose. In general, hyperglycemia was linked to worse outcome. While insulin therapy in subarachnoid hemorrhage patients was shown to effectively control plasma glucose levels, plasma glucose control was not necessarily reflective of cerebral glucose such that very tight glucose control may lead to neuroglycopenia. Furthermore, tight glycemic control was associated with an increased risk for hypoglycemia which was linked to worse outcome.

Glucose variability negatively impacts long-term functional outcome in patients with traumatic brain injury

PURPOSE

Significant glycemic excursions (so-called glucose variability) affect the outcome of generic critically ill patients but has not been well studied in patients with traumatic brain injury (TBI). The purpose of this study was to evaluate the impact of glucose variability on long-term functional outcome of patients with TBI.

MATERIAL AND METHODS

A noncomputerized tight glucose control protocol was used in our intensivist model surgical intensive care unit. The relationship between the glucose variability and long-term (a median of 6 months after injury) functional outcome defined by extended Glasgow Outcome Scale (GOSE) was analyzed using ordinal logistic regression models. Glucose variability was defined by SD and percentage of excursion (POE) from the preset range glucose level.

RESULTS

A total of 109 patients with TBI under tight glucose control had long-term GOSE evaluated. In univariable analysis, there was a significant association between lower GOSE score and higher mean glucose, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL but not POE 80 to 110. After adjusting for possible confounding variables in multivariable ordinal logistic regression models, higher SD, POE more than 60, POE 80 to 150, and single episode of glucose less than 60 mg/dL were significantly associated with lower GOSE score.

CONCLUSIONS

Glucose variability was significantly associated with poorer long-term functional outcome in patients with TBI as measured by the GOSE score. Well-designed protocols to minimize glucose variability may be key in improving long-term functional outcome.

Treating hyperglycemia in neurocritical patients: benefits and perils

There is growing debate over the value of intensive insulin therapy (IIT) in critically ill patients. Available trials have been performed in general medical or surgical intensive care units, and the results may not be directly applicable to patients with severe acute brain disease because these patients may have heightened susceptibility to hyperglycemia (HyperG) and hypoglycemia. Our objective was to review the pathophysiology and effects of HyperG and hypoglycemia in neurocritical patients and to analyze the potential role of IIT in this population. Source data were obtained from a PubMed search of the medical literature combining the terms HyperG, hypoglycemia, insulin, stroke, intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), traumatic brain injury (TBI), spinal cord injury (SCI), and related diagnoses. Brain metabolism is highly dependent on constant supply of glucose. As a consequence, the acutely injured brain is particularly sensitive to hypoglycemia, which can induce a state of energy failure (metabolic crisis). Meanwhile, neurocritical patients have a high prevalence of HyperG, and its occurrence is associated with poor outcome after acute ischemic stroke, ICH, SAH, and TBI. It is unclear whether this association is due to direct detrimental effects exerted by HyperG or simply represents a marker of severe brain injury. Insulin has been shown to have various potentially pleiotropic neuroprotective properties in experimental models. However, the safety and efficacy of IIT in patients with critical brain disease have not been well studied. Available results do not support the use of IIT to maintain strict normoglycemia in this population. Patients with critical brain disease should have frequent glucose monitoring because severe HyperG and even modest hypoglycemia may be detrimental. Careful use of insulin infusion protocols appears advisable, but maintenance of strict normoglycemia cannot be recommended. Rigorous studies must be conducted to assess the value of insulin therapy and to determine the optimal blood glucose targets in patients with the most common acute vascular and traumatic brain insults.

Glucose management in the neurosurgical patient: are we yet any closer?

PURPOSE OF REVIEW

This review focuses on recent findings in perioperative management of blood glucose control using intensive insulin therapy in neurosurgical and neurocritical care and in other intensive care unit patients. We also aim to address practical issues and make recommendations that may contribute to the safe clinical application of intensive insulin therapy targeted to optimize blood glucose control in these patients.

RECENT FINDINGS

Intensive insulin therapy targeted to obtain tight blood glucose control induces a substantial increase in the number of hypoglycemic episodes and mortality rate. On the contrary, hyperglycemia--both isolated episodes and high mean glucose levels--is associated with worsened neurologic outcome and increased mortality.

SUMMARY

In neurosurgical and neurocritical care as well as other intensive care unit patients, both hypoglycemia and hyperglycemia have significant adverse effects. The optimal glucose level remains under debate but significant steps have evolved with the call for judicious control and elimination of the historical approach to glycemic management, which underestimated drawbacks associated with dysglycemia. The increased incidence of hypoglycemia and mortality as well as the impact of hyperglycemia on worsening neurologic function in patients with acute brain damage heightens the need for more clinical studies on perioperative glucose management in these patients.

High blood glucose does not adversely affect outcome in moderately brain-injured rodents

In a number of clinical studies researchers have reported that acute hyperglycemia is associated with increased mortality and worsened neurological outcome in patients with traumatic brain injury (TBI). In contrast, it has been demonstrated that intensive insulin therapy to lower blood glucose can lead to an increased frequency of hypoglycemic episodes and poor outcome. Consistent with this, experimental and clinical studies have shown that TBI causes a "metabolic crisis" in the injured brain, suggesting that a reduction in glucose availability may exacerbate brain damage. We therefore examined the consequences of hyperglycemia on cognitive and pathological measures. Using a rodent model of TBI, we find that when acute hyperglycemia is induced in animals prior to injury, there is little to no change in motor and cognitive performance, contusion volume, or cerebral edema. To examine the consequences of persistent hyperglycemia (as seen in diabetic patients), animals were treated with streptozotocin (STZ) to induce type 1 diabetes. We find that the presence of persistent STZ-induced hyperglycemia results in a reduction of brain edema. Insulin therapy to reduce blood glucose reverses this beneficial effect of hyperglycemia. Taken together, our results indicate that an acute increase in blood glucose levels may not be harmful, and that intervention with insulin therapy to lower blood glucose levels in TBI patients may increase secondary brain damage.

A prospective observational study of the relationship of critical illness associated hyperglycaemia in medical ICU patients and subsequent development of type 2 diabetes

Introduction

Critical illness is commonly complicated by hyperglycaemia caused by mediators of stress and inflammation. Severity of disease is the main risk factor for development of hyperglycaemia, but not all severely ill develop hyperglycemia and some do even in mild disease. We hypothesised that acute disease only exposes a latent disturbance of glucose metabolism which puts those patients at higher risk for developing diabetes.

Methods

Medical patients with no history of impaired glucose metabolism or other endocrine disorder admitted to an intensive care unit between July 1998 and June 2004 were considered for inclusion. Glucose was measured at least two times a day, and patients were divided into the hyperglycaemia group (glucose ≥7.8 mmol/l) and normoglycaemia group. An oral glucose tolerance test was performed within six weeks after discharge to disclose patients with unknown diabetes or pre-diabetes who were excluded. Patients treated with corticosteroids and those terminally ill were also excluded from the follow-up which lasted for a minimum of five years with annual oral glucose tolerance tests.

Results

A five-year follow-up was completed for 398 patients in the normoglycaemia group, of which 14 (3.5%) developed type 2 diabetes. In the hyperglycaemia group 193 patients finished follow-up and 33 (17.1%) developed type 2 diabetes. The relative risk for type 2 diabetes during five years after the acute illness was 5.6 (95% confidence interval (CI) 3.1 to 10.2).

Conclusions

Patients with hyperglycaemia during acute illness who are not diagnosed with diabetes before or during the hospitalization should be considered a population at increased risk for developing diabetes. They should, therefore, be followed-up, in order to be timely diagnosed and treated.

Contemporary pharmacologic issues in the management of traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability in the United States. While there are no pharmacotherapeutic options currently available for attenuating the neurologic injury cascade after TBI, numerous pharmacologic issues are encountered in these critically ill patients. Adequate fluid resuscitation, reversal of coagulopathy, maintenance of cerebral perfusion, and treatment of intracranial hypertension are common interventions early in the treatment of TBI. Other deleterious complications such as venous thromboembolism, extremes in glucose concentrations, and stress-related mucosal disease should be anticipated and avoided. Early provision of nutrition and prevention of drug or alcohol withdrawal are also cornerstones of routine care in TBI patients. Prevention of infections and seizures may also be helpful. Clinicians caring for TBI patients should be familiar with the pharmacologic issues typical of this vulnerable population in order to develop optimal strategies of care to anticipate and prevent common complications.