Metabolism and nutrition in patients with moderate and severe traumatic brain injury: A systematic review

Clinical Outcomes of Early Versus Late Enteral Nutrition Support in Critically Ill Trauma Patients With Isolated Traumatic Brain Injury

INTRODUCTION

This study aims to compare the impact of early initiation of enteral feeding initiation on clinical outcomes in critically ill adult trauma patients with isolated traumatic brain injuries (TBI).

METHODS

A retrospective cohort analysis of the American College of Surgeons Trauma Quality Program Participant Use File 2017-2021 dataset of critically ill adult trauma patients with moderate to severe blunt isolated TBI. Outcomes included ICU length of stay (ICU-LOS), ventilation-free days (VFD), and complication rates. Timing cohorts were defined as very early (<6 hours), early (6-24 hours), intermediate (24-48 hours), and late (>48 hours).

RESULTS

9210 patients were included in the analysis, of which 952 were in the very early enteral feeding initiation group, 652 in the early, 695 in intermediate, and 6938 in the late group. Earlier feeding was associated with significantly shorter ICU-LOS (very early: 7.82 days; early: 11.28; intermediate 12.25; late 17.55; P < .001) and more VFDs (very early: 21.72 days; early: 18.81; intermediate 18.81; late 14.51; P < .001). Patients with late EF had a significantly higher risk of VAP than very early (OR .21, CI 0.12-.38, P < .001) or early EF (OR .33, CI 0.17-.65, P = .001), and higher risk of ARDS than the intermediate group (OR .23, CI 0.05-.925, P = .039).

CONCLUSION

Early enteral feeding in critically ill adult trauma patients with moderate to severe isolated TBI resulted in significantly fewer days in the ICU, more ventilation-free days, and lower odds of VAP and ARDS the sooner enteral feeding was initiated, with the most optimized outcomes within 6 hours.

Modified Nutrition Risk in the Critically ill score and mortality in critically ill patients with traumatic brain injury

BACKGROUND

Understanding the relationship between nutrition risk at admission to the intensive care unit (ICU) and the prognosis of patients with traumatic brain injury (TBI) may aid early recognition of high-risk patients.

METHODS

We extracted data from the Medical Information Mart for Intensive Care III and the electronic ICU Collaborative Research Databases. Using modified Nutrition Risk in the Critically ill score (mNUTRIC) within the first 24 h of ICU admission, 5153 patients were divided into three groups: low (≤1, n = 1765), moderate (2-4, n = 2574), and high (≥5, n = 814). The primary outcome was 28-day in-hospital mortality, and the secondary outcomes were 7-day in-hospital mortality, length of ICU stay, and duration of mechanical ventilation.

RESULTS

During the median follow-up time of 6.69 days, 647 deaths occurred in total. After adjustment for potential confounding factors, setting the low mNUTRIC group as a reference, the risk of 28-day mortality was increased in the high and moderate mNUTRIC groups (hazard ratio [HR]high vs low [95% CI]: 4.21 [2.70-6.58] and 2.84 [1.95-4.14], respectively). Similarly, high and moderate mNUTRIC scores are linked to a higher risk of 7-day mortality (PTrend  < 0.001) and a longer duration of mechanical ventilation (PTrend  < 0.001). The effect of mNUTRIC on mortality varied by serum glucose level (PInteraction  = 0.01). Lastly, those whose mNUTRIC scores deteriorated within the first 3 days have a 1.46 times greater risk of dying compared with patients with improved mNUTRIC scores.

CONCLUSIONS

Nutrition risk screening by mNUTRIC score at the time of admission to the ICU may improve mortality prediction.

Malnutrition in Patients With Moderate to Severe Acquired Brain Injury: Prevalence During 4 Weeks of Subacute Rehabilitation

ABSTRACT

BACKGROUND: Malnutrition is associated with high rates of complication, longer hospital stays, and increased morbidity and mortality. Malnutrition defined as undernutrition is common in patients with acquired brain injury (ABI); however, estimates vary remarkably. This study aimed to describe malnutrition at admission and after 4 weeks of subacute inpatient neurorehabilitation in patients with ABI using the new global consensus definition of malnutrition. METHODS: One hundred thirty-three patients with moderate to severe ABI consecutively admitted to a specialized neurorehabilitation hospital within a period of 4 months were screened for inclusion, of which 92 were included. Malnutrition was defined as at least 1 phenotypic criterion (weight loss, low body mass index, low muscle mass) and at least 1 etiologic criterion (reduced food intake, inflammation). Malnutrition on admission and after 4 weeks was compared using the McNemar test. RESULTS: The proportion of patients with malnutrition at admission was 42%, with more men (46%) than women (36%) fulfilling the criteria for malnutrition. The most frequent phenotypic and etiologic criteria were weight loss (56%) and inflammation (74%), respectively. During the 4 weeks of rehabilitation, the proportion of male patients fulfilling the individual criteria "weight loss" (difference, -21.4%) and "inflammation" (difference, -18.9%) decreased significantly; "low muscle mass" decreased borderline significant (difference, -8.9%), whereas "low body mass index" did not change. The proportion of female patients fulfilling individual criteria for malnutrition was stable or increased nonsignificantly. CONCLUSION: Malnutrition was common at admission to neurorehabilitation in patients with moderate to severe ABI, with more men than women fulfilling the criteria for malnutrition. The nutritional status improved after 4 weeks of rehabilitation in male patients, whereas it was largely unchanged in female patients. The results provide the basis for monitoring high-quality nutritional nursing care.

The Biomechanical Characteristics of Swallowing in Tracheostomized Patients with Aspiration following Acquired Brain Injury: A Cross-Sectional Study

Objectives: Investigate the biomechanical characteristics in tracheostomized patients with aspiration following acquired brain injury (ABI) and further explore the relationship between the biomechanical characteristics and aspiration. Methods: This is a single-center cross-sectional study. The tracheostomized patients with aspiration following ABI and age-matched healthy controls were recruited. The biomechanical characteristics, including velopharynx (VP) maximal pressure, tongue base (TB) maximal pressure, upper esophageal sphincter (UES) residual pressure, UES relaxation duration, and subglottic pressure, were examined by high-resolution manometry and computational fluid dynamics simulation analysis. The penetration−aspiration scale (PAS) score was evaluated by a videofluoroscopic swallowing study. Results: Fifteen healthy subjects and fifteen tracheostomized patients with aspiration following ABI were included. The decreased VP maximal pressure, increased UES residual pressure, and shortened UES relaxation duration were found in the patient group compared with the control group (p < 0.05). Furthermore, the subglottic pressure significantly decreased in patients (p < 0.05), while no significant difference was found in TB maximal pressure between groups (p > 0.05). In addition, in the patient group, VP maximal pressure (rs = −0.439; p = 0.015), UES relaxation duration (rs = −0.532; p = 0.002), and the subglottic pressure (rs = −0.775; p < 0.001) were negatively correlated with the PAS score, while UES residual pressure (rs = 0.807; p < 0.001) was positively correlated with the PAS score (p < 0.05), the correlation between TB maximal pressure and PAS score (rs = −0.315; p = 0.090) did not reach statistical significance. Conclusions: The biomechanical characteristics in tracheostomized patients with aspiration following ABI might manifest as decreased VP maximal pressure and subglottic pressure, increased UES residual pressure, and shortened UES relaxation duration, in which VP maximal pressure, UES relaxation duration, subglottic pressure, and UES residual pressure were correlated with aspiration.

What is the nutritional status of patients with prolonged disorders of consciousness? A retrospective cross-sectional study

BACKGROUND

Nutritional status of patients with disorders of consciousness (DoC) is poorly studied.

OBJECTIVES

To evaluate the relationship between nutritional status (body mass index, daily calories intake) and clinical variables (level of consciousness, time since injury, diagnosis, etiology and spastic muscle overactivity; SMO,) in patients with prolonged DoCor emerging. Our main hypotheses are i) patients with lower level of consciousness (UWS) have worse nutritional status compared to patients in minimally conscious state (MCS) and ii) SMO could influence nutritional status.

METHODS AND RESULTS

Among the 80 patients included in the study (19 UWS, 47 MCS, 14 emerging MCS; 43 ± 15 yo; 3 ± 4 years post-injury, 35 traumatic etiology, 34 females), 9% were at risk to be undernourished, with no differences between UWS and MCS. Patients without SMO had a higher BMI compared to patients with severe SMO. Compared to the recommended daily calories intake, patients with the highest BMI received less calories and patients with the lowest BMI received more calories. We observed a negative correlation between SMO (in lower limbs) and BMI.

CONCLUSION

Our study shows that most patients are well nourished, independently from the level of consciousness. SMO may require additional calories in patients' daily needs; however, longitudinal studies are needed to explore the causal relationship between these variables.

Traumatic brain injury alters the gut-derived serotonergic system and associated peripheral organs

Most efforts to understand the pathology of traumatic brain injury (TBI) have been centered on the brain, ignoring the role played by systemic physiology. Gut-derived serotonin is emerging as a major regulator of systemic homeostasis involving various organs and tissues throughout the body. Here, we shed light on the roles occupied by gut-derived serotonin and its downstream metabolic targets in the systemic pathogenesis of TBI. Male C57BL/6J mice were subjected to a fluid percussion injury (FPI) and RT-qPCR was used to examine mRNA levels in intestine, liver, and adipose tissue. In the intestinal tract, TBI transiently downregulated enteric neuronal markers Chat and Nos1 in the duodenum and colon, and altered colonic genes related to synthesis and degradation of serotonin, favoring an overall serotonin downregulation. There also was a decrease in serotonin fluorescence intensity in the colonic mucosa and reduced circulating blood serotonin levels, with concurrent alterations in serotonin-associated gene expression in downstream tissues after TBI (i.e., upregulation of serotonin receptor Htr2a and dysregulation of genes associated with lipid metabolism in liver and adipose). Levels of commensal bacterial species were also altered in the gut and were associated with TBI-mediated changes in the colonic serotonin system. Our findings suggest that TBI alters peripheral serotonin homeostasis, which in turn may impact gastrointestinal function, gut microbiota, and systemic energy balance. These data highlight the importance of building an integrative view of the role of systemic physiology in TBI pathogenesis to assist in the development of effective TBI treatments.

Nutrition Management in Patients With Traumatic Brain Injury: A Narrative Review

Traumatic brain injury (TBI) is a major cause of long-term physical and psychological disability and death. In patients with TBI, undernutrition is associated with an increased mortality rate, more infectious complications, and worse neurologic outcomes. Therefore, timely and effective nutritional therapy is particularly crucial in the management of TBI to improve patients' prognoses. This narrative review summarizes the issues encountered in clinical practice for patients with neurotrauma who receive acute and post-acute in-patient rehabilitation services, and it comprehensively incorporates a wide range of studies, including recent clinical practice guidelines (CPGs), with the aim of better understanding the current evidence for optimal nutritional therapy focused on TBI patients. Recent CPGs were reviewed for 6 topics: 1) hypermetabolism and variation in energy expenditure in patients with TBI, 2) delayed gastric emptying and intolerance to enteral nutrition, 3) decision-making on the route and timing of access in patients with TBI who are unable to maintain volitional intake (enteral nutrition versus parenteral nutrition), 4) decision-making on the enteral formula (standard or immune-modulating formulas), 5) glycemic control, and 6) protein support. We also identified areas that need further research in the future.

Future Perspectives in Spinal Cord Repair: Brain as Saviour? TSCI with Concurrent TBI: Pathophysiological Interaction and Impact on MSC Treatment

Traumatic spinal cord injury (TSCI), commonly caused by high energy trauma in young active patients, is frequently accompanied by traumatic brain injury (TBI). Although combined trauma results in inferior clinical outcomes and a higher mortality rate, the understanding of the pathophysiological interaction of co-occurring TSCI and TBI remains limited. This review provides a detailed overview of the local and systemic alterations due to TSCI and TBI, which severely affect the autonomic and sensory nervous system, immune response, the blood-brain and spinal cord barrier, local perfusion, endocrine homeostasis, posttraumatic metabolism, and circadian rhythm. Because currently developed mesenchymal stem cell (MSC)-based therapeutic strategies for TSCI provide only mild benefit, this review raises awareness of the impact of TSCI-TBI interaction on TSCI pathophysiology and MSC treatment. Therefore, we propose that unravelling the underlying pathophysiology of TSCI with concomitant TBI will reveal promising pharmacological targets and therapeutic strategies for regenerative therapies, further improving MSC therapy.

Body composition measures may help target fundamental nutritional nursing efforts in rehabilitating patients with acquired brain injury

Aim

To illuminate using body composition measurements for malnutrition measured by Bio Impedance Analysis (BIA), as opposed to body mass index (BMI), and discuss benefits and burdens for fundamental nursing care.

Design

A second analysis of a prospective, descriptive cohort study, targeting fundamental nursing care elements.

Methods

This postevaluation study explored data from a prospective, descriptive cohort study, which consecutively included 92 patients admitted for neurorehabilitation care. Measures of nutritional status were BMI and FFMI. Chi‐Square test and Multivariable logistic regression were used.

Results

Body composition measures rather than BMI contributed to target individual nutritional nursing care as this measure detected more patients at potential risk of malnutrition and indicated minor changes in the nutritional state. Transitions from being malnourished to a normal nutritional status occurred in 29% using the BMI definition while it was the case in 40% of individuals with malnutrition defined by the body composition.

Gastrointestinal Complications in Critically Ill Children: Experience from A Resource-Limited Country

Objectives:

To determine the frequency and predictors of outcome of gastrointestinal complications (GIC) in critically ill children.

Methods:

This descriptive study was prospectively conducted in The Pediatric Intensive Care Unit (PICU), The Aga Khan University Hospital (AKUH), Karachi, from September 2015 to January 2017. After obtaining approval from the Ethical Review Committee of AKUH and informed consent from the parents, all children (aged one month to 18 years), of either gender, admitted to the Pediatric Intensive Care Unit (PICU) during the study period were included. The frequency of the defined GIC: vomiting, high gastric residue volume (GRV), diarrhea, constipation, and gastrointestinal bleed were recorded daily for the first week of the PICU stay. The data was collected by the primary investigator on a predesigned data collection form with inclusion of variables and predictors in light of existing literature and local expertise. The questionnaire was shared with the Pediatric Critical Care Medicine faculty and a consensus was sought on the elements to be incorporated.

Results:

GIC developed within the first 48 hours of admission in 78 (41%) patients. Of the patients who developed GIC, 37 (47.4%) patients developed high GRV: 31 (39.7%) patients developed constipation, 18 (23.1%) patients developed vomiting, 14 (17.9%) patients developed abdominal distension. With regards to prevalence by occurrence, 32/78 (41%) of patients presented with two GI complications, followed by 21 patients (27%) who presented with a single GIC. Only 11 patients (14%) presented with more than three complications. Median length of stay was higher in patients with GIC (8 days) than with those who did not develop GIC (4 days). The frequency of gastrointestinal complications was significantly higher in children receiving mechanical ventilation, on sedatives and relaxants and those with multiorgan dysfunction syndrome (MODS) and inotropes

Conclusion:

GI complications are a frequent occurrence in the PICU and are associated with worse clinical outcomes. The use of sedative drugs and the presence of shock with MODS were amongst the important contributing factors.

Bidirectional Brain-Systemic Interactions and Outcomes After TBI

Traumatic brain injury (TBI) is a debilitating disorder associated with chronic progressive neurodegeneration and long-term neurological decline. Importantly, there is now substantial and increasing evidence that TBI can negatively impact systemic organs, including the pulmonary, gastrointestinal (GI), cardiovascular, renal, and immune system. Less well appreciated, until recently, is that such functional changes can affect both the response to subsequent insults or diseases, as well as contribute to chronic neurodegenerative processes and long-term neurological outcomes. In this review, we summarize evidence showing bidirectional interactions between the brain and systemic organs following TBI and critically assess potential underlying mechanisms.

Nutritional and metabolic supplementation for the injured brain: an update

PURPOSE OF REVIEW

Energy dysfunction is increasingly recognized as a key factor in the pathogenesis of acute brain injury (ABI). This one characterized by a high metabolic rate and nitrogen loss is often associated with an undernutrition support. We review the metabolism evolution and nutritional status in brain injured patient and summarize evidence on nutritional support in this condition.

RECENT FINDINGS

The role of nutrition support for improving prognosis in brain injured patient has been underlined recently. A fast nutrition institution whatever the route is essential to prevent an imbalance in caloric support. Moreover, hypermetabolic state must be prevented with a sufficient nitrogen support. Glycemic control is particularly relevant in this group of patient, with the discovery of new fuel that could potentially improve cerebral metabolism and replace glucose. Few data support also the use of immunonutrition input in this group of patients.

SUMMARY

Nutritional support is a key parameter in brain injured patient and must be initiated quickly to counteract hypermetabolic state by caring to improve caloric and nitrogen input. Recent clinical data support the use of immunonutrition, glutamine and zinc in this particular setting.

Plasma metabolomics pilot study suggests age and sex-based differences in the metabolic response to traumatic injury

INTRODUCTION

Age and sex affect outcomes from trauma. Older patients tend to be under-triaged, consume more healthcare resources, and experience worse outcomes relative to younger patients. Sex has also been associated with different outcomes, with women experiencing better outcomes than men. While baseline metabolism differs with both age and sex, no study has examined how these differences affect the response to trauma. We used high-throughput metabolomics to assess metabolic differences associated with blunt trauma according to age and sex.

METHODS

Metabolic profiles were constructed using nuclear magnetic resonance spectroscopy for trauma patients age 21-40 years (n = 20, 55% male) and >65 years (n = 22, 41% male) from plasma samples obtained on Day 1 and Day 3 of each patient's hospital stay. These were compared to profiles constructed from plasma obtained from healthy controls of the same age (21-40: n = 23, 61% male; 65+: n = 26, 50% male). Differences in metabolic profiles were assessed with partial least squares discriminant analysis.

RESULTS

Trauma elicits an overwhelming global stress response that includes more subtle differences in metabolism related to age and gender. Significant differences due to normal aging were also identified. Many of the metabolites measured were present in similar levels in healthy controls age 65+ as they were in trauma patients of all ages. Sex-based differences in metabolism were observed in younger trauma patients on Day 3 but not in older patients.

CONCLUSIONS

Differences in energy metabolism and oxidative stress were implicated in the response to trauma in all patients. Older trauma patients may enter the trauma state with pre-existing oxidative stress and energy deficits that complicate recovery. Sex-based differences in recovery from trauma support the large body of work demonstrating the role of sex in recovery from trauma.

Mild Traumatic Brain Injury in Mice Beneficially Alters Lung NK1R and Structural Protein Expression to Enhance Survival after Pseudomonas aeruginosa Infection

Mild traumatic brain injury (mTBI) in a murine model increases survival to a bacterial pulmonary challenge compared with blunt tail trauma (TT). We hypothesize substance P and its receptor, the neurokinin 1 receptor (NK1R; official name TACR1), play a role in the increased survival of mTBI mice. Mice were subjected to mTBI or TT, and 48 hours after trauma, the levels of NK1R mRNA and protein were significantly up-regulated in mTBI lungs. Examination of the lung 48 hours after injury by microarray showed significant differences in the expression of 433 gene sets between groups, most notably genes related to intercellular proteins. Despite down-regulated gene expression of connective proteins, the presence of an intact pulmonary vasculature was supported by normal histology and bronchoalveolar lavage protein levels. To determine whether these mTBI-induced lung changes benefited in vivo responses, two chemotactic stimuli (a CXCL1 chemokine and a live Pseudomonas aeruginosa infection) were administered 48 hours after trauma. For both stimuli, mTBI mice recruited more neutrophils to the lung 4 hours after instillation (CXCL1: mTBI = 6.3 ± 1.3 versus TT = 3.3 ± 0.7 neutrophils/mL; Pseudomonas aeruginosa: mTBI = 9.4 ± 1.4 versus TT = 5.3 ± 1.1 neutrophils/mL). This study demonstrates that the downstream consequences of mTBI on lung NK1R levels and connective protein expression enhance neutrophil recruitment to a stimulus that may contribute to increased survival.

The currency, completeness and quality of systematic reviews of acute management of moderate to severe traumatic brain injury: A comprehensive evidence map

OBJECTIVE

To appraise the currency, completeness and quality of evidence from systematic reviews (SRs) of acute management of moderate to severe traumatic brain injury (TBI).

METHODS

We conducted comprehensive searches to March 2016 for published, English-language SRs and RCTs of acute management of moderate to severe TBI. Systematic reviews and RCTs were grouped under 12 broad intervention categories. For each review, we mapped the included and non-included RCTs, noting the reasons why RCTs were omitted. An SR was judged as 'current' when it included the most recently published RCT we found on their topic, and 'complete' when it included every RCT we found that met its inclusion criteria, taking account of when the review was conducted. Quality was assessed using the AMSTAR checklist (trichotomised into low, moderate and high quality).

FINDINGS

We included 85 SRs and 213 RCTs examining the effectiveness of treatments for acute management of moderate to severe TBI. The most frequently reviewed interventions were hypothermia (n = 17, 14.2%), hypertonic saline and/or mannitol (n = 9, 7.5%) and surgery (n = 8, 6.7%). Of the 80 single-intervention SRs, approximately half (n = 44, 55%) were judged as current and two-thirds (n = 52, 65.0%) as complete. When considering only the most recently published review on each intervention (n = 25), currency increased to 72.0% (n = 18). Less than half of the 85 SRs were judged as high quality (n = 38, 44.7%), and nearly 20% were low quality (n = 16, 18.8%). Only 16 (20.0%) of the single-intervention reviews (and none of the five multi-intervention reviews) were judged as current, complete and high-quality. These included reviews of red blood cell transfusion, hypothermia, management guided by intracranial pressure, pharmacological agents (various) and prehospital intubation. Over three-quarters (n = 167, 78.4%) of the 213 RCTs were included in one or more SR. Of the remainder, 17 (8.0%) RCTs post-dated or were out of scope of existing SRs, and 29 (13.6%) were on interventions that have not been assessed in SRs.

CONCLUSION

A substantial number of SRs in acute management of moderate to severe TBI lack currency, completeness and quality. We have identified both potential evidence gaps and also substantial research waste. Novel review methods, such as Living Systematic Reviews, may ameliorate these shortcomings and enhance utility and reliability of the evidence underpinning clinical care.

Bidirectional brain-gut interactions and chronic pathological changes after traumatic brain injury in mice

OBJECTIVES

Traumatic brain injury (TBI) has complex effects on the gastrointestinal tract that are associated with TBI-related morbidity and mortality. We examined changes in mucosal barrier properties and enteric glial cell response in the gut after experimental TBI in mice, as well as effects of the enteric pathogen Citrobacter rodentium (Cr) on both gut and brain after injury.

METHODS

Moderate-level TBI was induced in C57BL/6mice by controlled cortical impact (CCI). Mucosal barrier function was assessed by transepithelial resistance, fluorescent-labelled dextran flux, and quantification of tight junction proteins. Enteric glial cell number and activation were measured by Sox10 expression and GFAP reactivity, respectively. Separate groups of mice were challenged with Cr infection during the chronic phase of TBI, and host immune response, barrier integrity, enteric glial cell reactivity, and progression of brain injury and inflammation were assessed.

RESULTS

Chronic CCI induced changes in colon morphology, including increased mucosal depth and smooth muscle thickening. At day 28 post-CCI, increased paracellular permeability and decreased claudin-1 mRNA and protein expression were observed in the absence of inflammation in the colon. Colonic glial cell GFAP and Sox10 expression were significantly increased 28days after brain injury. Clearance of Cr and upregulation of Th1/Th17 cytokines in the colon were unaffected by CCI; however, colonic paracellular flux and enteric glial cell GFAP expression were significantly increased. Importantly, Cr infection in chronically-injured mice worsened the brain lesion injury and increased astrocyte- and microglial-mediated inflammation.

CONCLUSION

These experimental studies demonstrate chronic and bidirectional brain-gut interactions after TBI, which may negatively impact late outcomes after brain injury.

Early feeds not force feeds: Enteral nutrition in traumatic brain injury

BACKGROUND

Brain Trauma Foundation guidelines recommend the early use of enteral nutrition to optimize recovery following traumatic brain injury (TBI). Our aim was to examine the effect of early feeds (≤24 hours) on clinical outcomes after TBI.

METHODS

We performed a 3-year retrospective study of patients with severe TBI (Glasgow Coma Scale score <8) who were intubated, admitted to the intensive care unit (ICU), and received tube feeds. Early tube feeds (early TF) were defined as initiation of tube feeds within 24 hours, whereas late tube feeds (late TF) were defined as initiation of tube feeds after 24 hours. Outcome measures included pneumonia rates, days on ventilator, hospital and ICU stay, and mortality rates.

RESULTS

A total of 90 patients (early TF: 58, late TF: 32) were included, of which 73.3% were male, mean age was 42 (SD, 20) years, and median head Abbreviated Injury Scale score was 4 (range, 3-5). There was no difference in age (p = 0.1), head Abbreviated Injury Scale score (p = 0.5), or admission Glasgow Coma Scale score (p = 0.9) between the two groups. Patients with early TF were associated with higher number of ICU days (p = 0.03) and higher pneumonia rates (p = 0.04), but there was no significant difference in mortality (p = 0.44) as compared with those who underwent late TF.

CONCLUSIONS

Although early tube feeds are known to improve outcomes in TBI patients, our data suggest that early feeds in TBI patients are associated with higher rates of pneumonia and greater hospital resource utilization.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Comparison of erythromycin versus metoclopramide for gastric feeding intolerance in patients with traumatic brain injury: A randomized double-blind study

Background:

No randomized controlled trial demonstrates the efficacy of erythromycin or metoclopramide in patients with traumatic brain injury (TBI). This study was conducted to determine the efficacy of metoclopramide and erythromycin for improving gastric aspirate volume (GAV) in patients with TBI.

Materials and Methods:

Patients with Glasgow coma score more than 5 admitted to trauma Intensive Care Unit within 72 h of head injury were assessed for eligibility. 115 patients were prospectively randomized to receive metoclopramide, erythromycin, or placebo eighth hourly. Gastric feeding intolerance was defined as GAV more than 150 ml with abdominal symptoms. Two consecutive high GAV was defined as feeding failure. Feeding failure was treated by increasing the frequency of dose to 6 hourly in metoclopramide and erythromycin group. Combination therapy with both drugs was given as rescue in the placebo group.

Results:

Incidence of high GAV was as high as 60.5% in placebo group. Use of erythromycin was associated with a decrease in the incidence of feeding intolerance to 28.9% (P = 0.006). Although feed intolerance decreased to 43.6% in metoclopramide group, values did not reach statistical significance. The proportion of patients not having high GAV at different days were significantly higher in erythromycin group (P = 0.027, log-rank test). There was no difference in the proportion of patients not having feeding failure in three groups with increasing number of days.

Conclusion:

There was a significant decrease in the incidence of high GAV with the use of erythromycin when compared to metoclopramide and placebo.

Nutrition support practices in critically ill head-injured patients: a global perspective

Background

Critical illness following head injury is associated with a hypermetabolic state but there are insufficient epidemiological data describing acute nutrition delivery to this group of patients. Furthermore, there is little information describing relationships between nutrition and clinical outcomes in this population.

Methods

We undertook an analysis of observational data, collected prospectively as part of International Nutrition Surveys 2007-2013, and extracted data obtained from critically ill patients with head trauma. Our objective was to describe global nutrition support practices in the first 12 days of hospital admission after head trauma, and to explore relationships between energy and protein intake and clinical outcomes. Data are presented as mean (SD), median (IQR), or percentages.

Results

Data for 1045 patients from 341 ICUs were analyzed. The age of patients was 44.5 (19.7) years, 78 % were male, and median ICU length of stay was 13.1 (IQR 7.9-21.6) days. Most patients (94 %) were enterally fed but received only 58 % of estimated energy and 53 % of estimated protein requirements. Patients from an ICU with a feeding protocol had greater energy and protein intakes (p <0.001, 0.002 respectively) and were more likely to survive (OR 0.65; 95 % CI 0.42-0.99; p = 0.043) than those without. Energy or protein intakes were not associated with mortality. However, a greater energy and protein deficit was associated with longer times until discharge alive from both ICU and hospital (all p <0.001).

Conclusion

Nutritional deficits are commonplace in critically ill head-injured patients and these deficits are associated with a delay to discharge alive.

Monitoring nutrition and glucose in acute brain injury

The metabolic response to injury is well described; however, very little is understood about optimal markers to measure this response. This summary will address the current evidence about monitoring nutritional status including blood glucose after acute brain injury (ABI). An electronic literature search was conducted for English language articles describing the testing, utility, and optimal methods to measure nutritional status and blood glucose levels in the neurocritical care population. A total of 45 articles were included in this review. Providing adequate and timely nutritional support can help improve outcome after ABI. However, the optimal content and total nutrition requirements remain unclear. In addition, how best to monitor the nutritional status in ABI is still being elucidated, and at present, there is no validated optimal method to monitor the global response to nutritional support on a day-to-day basis in ABI patients. Nitrogen balance may be monitored to assess the adequacy of caloric intake as it relates to protein energy metabolism, but indirect calorimetry, anthropometric measurement, or serum biomarker requires further validation. The adverse effects of hyperglycemia in ABI are well described, and data indicate that blood glucose should be carefully controlled in critically ill patients. However, the optimal frequency or duration for blood glucose monitoring after ABI remains poorly defined. There are significant knowledge gaps about monitoring nutritional status and response to nutritional interventions in ABI; these need to be addressed and hence few recommendations can be made. The optimal frequency and duration of blood glucose monitoring need further study.

Static and Dynamic Factors Promoting Resilience following Traumatic Brain Injury: A Brief Review

Traumatic brain injury (TBI) is the greatest contributing cause of death and disability among children and young adults in the United States. The current paper briefly summarizes contemporary literature on factors that can improve outcomes (i.e., promote resilience) for children and adults following TBI. For the purpose of this paper, the authors divided these factors into static or unmodifiable factors (i.e., age, sex, intellectual abilities/education, and preinjury psychiatric history) and dynamic or modifiable factors (i.e., socioeconomic status, family functioning/social support, nutrition, and exercise). Drawing on human and animal studies, the research reviewed indicated that these various factors can improve outcomes in multiple domains of functioning (e.g., cognition, emotion regulation, health and wellness, behavior, etc.) following a TBI. However, many of these factors have not been studied across populations, have been limited to preclinical investigations, have been limited in their scope or follow-up, or have not involved a thorough evaluation of outcomes. Thus, although promising, continued research is vital in the area of factors promoting resilience following TBI in children and adults.

Enteral Nutrition for Patients With Traumatic Brain Injury in the Rehabilitation Setting: Associations With Patient Preinjury and Injury Characteristics and Outcomes

OBJECTIVE

To determine the association of enteral nutrition (EN) with patient preinjury and injury characteristics and outcomes for patients receiving inpatient rehabilitation after traumatic brain injury (TBI).

DESIGN

Prospective observational study.

SETTING

Nine rehabilitation centers.

PARTICIPANTS

Patients (N=1701) admitted for first full inpatient rehabilitation after TBI.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

FIM at rehabilitation discharge, length of stay, weight loss, and various infections.

RESULTS

There were many significant differences in preinjury and injury characteristics between patients who received EN and patients who did not. After matching patients with a propensity score of >40% for the likely use of EN, patients receiving EN with either a standard or a high-protein formula (>20% of calories coming from protein) for >25% of their rehabilitation stay had higher FIM motor and cognitive scores at rehabilitation discharge and less weight loss than did patients with similar characteristics not receiving EN.

CONCLUSIONS

For patients receiving inpatient rehabilitation after TBI and matched on a propensity score of >40% for the likely use of EN, clinicians should strongly consider, when possible, EN for ≥25% of the rehabilitation stay and especially with a formula that contains at least 20% protein rather than a standard formula.

Immune enhancing nutrition in traumatic brain injury - A preliminary study

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Certain patients appear to benefit when they receive immune enhancing additives, such as glutamine, arginine, and omega-3 fatty acids. We hypothesized that TBI patients given enteral feedings containing these supplements may have improved nutrition measures and infection rates when compared to standard tube feedings. This is a retrospective review of patients from a Level-One trauma center from July 2009 to July 2013. A total of 240 TBI patients received either an immune enhancing nutrition (IEN) formula (n = 126), or a standard formula (SF) (n = 114) based on the attending surgeon's preference. Data collected included demographic information, infection information and outcome measures. Patients were similar in terms of age, ISS, head AIS, and initial prealbumin level. Patients receiving IEN were found to have lower rates of blood stream infections (10.3% vs 19.3%, p < 0.05), whereas pneumonia and UTI rates were similar between groups. In addition, both groups had similar rates of all-cause mortality and hospital length of stay, however IEN patients spent longer in the ICU and on ventilators. In TBI patients receiving IEN, prealbumin levels were higher at the second, third, and fourth week of admission (week 2 - 22.2 vs 17.4, p = 0.006; week 3 - 24.6 vs 20.1, p = 0.04; week 4 - 26.3 vs 22.1, p = 0.19; week 5 - 25.8 vs 20.3, p = 0.21). This study suggests that patients with traumatic brain injury who receive IEN are more likely to have increased prealbumin levels perhaps reflecting improved nutrition throughout their hospital stay and may show some benefit in rates of infections, particularly in bacteremia.

Subacute complications during recovery from severe traumatic brain injury: frequency and associations with outcome

BACKGROUND

Medical complications after severe traumatic brain injury (S-TBI) may delay or prevent transfer to rehabilitation units and impact on long-term outcome.

OBJECTIVE

Mapping of medical complications in the subacute period after S-TBI and the impact of these complications on 1-year outcome to inform healthcare planning and discussion of prognosis with relatives.

SETTING

Prospective multicentre observational study. Recruitment from 6 neurosurgical centres in Sweden and Iceland.

PARTICIPANTS AND ASSESSMENTS

Patients aged 18-65 years with S-TBI and acute Glasgow Coma Scale 3-8, who were admitted to neurointensive care. Assessment of medical complications 3 weeks and 3 months after injury. Follow-up to 1 year. 114 patients recruited with follow-up at 1 year as follows: 100 assessed, 7 dead and 7 dropped out.

OUTCOME MEASURE

Glasgow Outcome Scale Extended.

RESULTS

68 patients had ≥1 complication 3 weeks after injury. 3 weeks after injury, factors associated with unfavourable outcome at 1 year were: tracheostomy, assisted ventilation, on-going infection, epilepsy and nutrition via nasogastric tube or percutaneous endoscopic gastroscopy (PEG) tube (univariate logistic regression analyses). Multivariate analysis demonstrated that tracheostomy and epilepsy retained significance even after incorporating acute injury severity into the model. 3 months after injury, factors associated with unfavourable outcome were tracheostomy and heterotopic ossification (Fisher's test), infection, hydrocephalus, autonomic instability, PEG feeding and weight loss (univariate logistic regression). PEG feeding and weight loss at 3 months were retained in a multivariate model.

CONCLUSIONS

Subacute complications occurred in two-thirds of patients. Presence of a tracheostomy or epilepsy at 3 weeks, and of PEG feeding and weight loss at 3 months, had robust associations with unfavourable outcome that were incompletely explained by acute injury severity.

Death following traumatic brain injury in Drosophila is associated with intestinal barrier dysfunction

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Unfavorable TBI outcomes result from primary mechanical injuries to the brain and ensuing secondary non-mechanical injuries that are not limited to the brain. Our genome-wide association study of Drosophila melanogaster revealed that the probability of death following TBI is associated with single nucleotide polymorphisms in genes involved in tissue barrier function and glucose homeostasis. We found that TBI causes intestinal and blood–brain barrier dysfunction and that intestinal barrier dysfunction is highly correlated with the probability of death. Furthermore, we found that ingestion of glucose after a primary injury increases the probability of death through a secondary injury mechanism that exacerbates intestinal barrier dysfunction. Our results indicate that natural variation in the probability of death following TBI is due in part to genetic differences that affect intestinal barrier dysfunction.

DOI:http://dx.doi.org/10.7554/eLife.04790.001

Traumatic brain injury (TBI) caused by a violent blow to the head or body and the resultant collision of the brain against the skull is a major cause of disability and death in humans. Primary injury to the brain triggers secondary injuries that further damage the brain and other organs, generating many of the detrimental consequences of TBI. However, despite decades of study, the exact nature of these secondary injuries and their origin are poorly understood. A better understanding of secondary injuries should help to develop novel therapies to improve TBI outcomes in affected individuals.

To obtain this information, in 2013 researchers devised a method to inflict TBI in the common fruit fly, Drosophila melanogaster, an organism that is readily amenable to detailed genetic and molecular studies. This investigation demonstrated that flies subjected to TBI display many of the same symptoms observed in humans after a brain injury, including temporary loss of mobility and damage to the brain that becomes worse over time. In addition, many of the flies die within 24 hr after brain injury.

Now Katzenberger et al. use this experimental system to investigate the secondary injuries responsible for these deaths. First, genetic variants were identified that confer increased or decreased susceptibility to death after brain injury. Several of the identified genes affect the structural integrity of the intestinal barrier that isolates the contents of the gut—including nutrients and bacteria—from the circulatory system. Katzenberger et al. subsequently found that the breakdown of this barrier after brain injury permits bacteria and glucose to leak out of the intestine. Treating flies with antibiotics did not increase survival, whereas reducing glucose levels in the circulatory system after brain injury did. Thus, Katzenberger et al. conclude that high levels of glucose in the circulatory system, a condition known as hyperglycemia, is a key culprit in death following TBI.

Notably, these results parallel findings in humans, where hyperglycemia is highly predictive of death following TBI. Similarly, individuals with diabetes have a significantly increased risk of death after TBI. These results suggest that the secondary injuries leading to death are the same in flies and humans and that further studies in flies are likely to provide additional new information that will help us understand the complex consequences of TBI. Important challenges remain, including understanding precisely how the brain and intestine communicate, how injury to the brain leads to disruption of the intestinal barrier, and why elevated glucose levels increase mortality after brain injury. Answers to these questions could help pave the way to new therapies for TBI.

DOI:http://dx.doi.org/10.7554/eLife.04790.002

Nutrition therapy in the optimisation of health outcomes in adult patients with moderate to severe traumatic brain injury: findings from a scoping review

INTRODUCTION

Patients who have sustained traumatic brain injury (TBI) have increased nutritional requirements yet are often unable to eat normally, and adequate nutritional therapy is needed to optimise recovery. The aim of the current scoping review was to describe the existing evidence for improved outcomes with optimal nutrition therapy in adult patients with moderate to severe TBI, and to identify gaps in the literature to inform future research.

METHODS

Using an exploratory scoping study approach, Medline, Cinahl, Embase, CENTRAL, the Neurotrauma reviews in the Global Evidence Mapping (GEM) Initiative, and Evidence Reviews in Acquired Brain Injury (ERABI) were searched from 2003 to 14 November 2013 using variations of the search terms 'traumatic brain injury' and 'nutrition'. Articles were included if they reported mortality, morbidity, or length of stay outcomes, and were classified according to the nature of nutrition intervention and study design.

RESULTS

Twenty relevant articles were identified of which: 12 were original research articles; two were systematic reviews; one a meta-analysis; and five were narrative reviews. Of these, eleven explored timing of feed provision, eight explored route of administration of feeding, nine examined the provision of specific nutrients, and none examined feeding environment. Some explored more than one intervention. Three sets of guidelines which contain feeding recommendations were also identified.

DISCUSSION

Inconsistency within nutrition intervention methods and outcome measures means that the present evidence base is inadequate for the construction of best practice guidelines for nutrition and TBI. Further research is necessary to elucidate the optimal nutrition therapy for adults with TBI with respect to the timing, route of administration, nutrient provision and feeding environment. A consensus on the ideal outcome measure and the most appropriate method and timing of its measurement is required as a foundation for this evidence base.

The impacts of injury at the individual, community and societal levels: a systematic meta-review

OBJECTIVES

Injury is a major public health problem. While the impacts of injury on the injured person are well documented, there is relatively little knowledge about the impacts of injury on those individuals and groups in the community connected to the injured person. This study seeks to describe this breadth of research using a meta-review methodology.

STUDY DESIGN

Systematic meta-review.

METHODS

To gain a better understanding of the known impacts of injury on family, community and society, a systematic meta-review of injury outcomes research literature was conducted. Seventy-eight peer-reviewed published literature reviews were included in the meta-review.

RESULTS

Of these, 70 reported outcomes at the level of the injured person including mortality, body functions, activity and participation limitations. Nine reviews reported impacts at the level of the community including impacts on family members, work colleagues and carers. Six studies reported impacts at the societal level including economic, health system and injury compensation system impacts.

CONCLUSIONS

In summary, the meta-review identified a substantial body of knowledge at the individual level outcomes of injury, and a relative lack of information regarding the community and societal impacts of injury. An injury outcome framework is proposed on the basis of the findings of the meta-review to guide future research activity, particularly with regard to injury outcome domains where there is currently limited evidence. A comprehensive framework that takes account of all levels of impact is necessary for effective policies, systems and strategies to support recovery following injury.

Effects of traumatic brain injury on intestinal contractility

BACKGROUND

Patients with traumatic brain injury (TBI) often suffer from gastrointestinal dysfunction including intolerance to enteral feedings. However, it is unclear how TBI affects small intestinal contractile activity. The purpose of this study was to determine if TBI affects intestinal smooth muscle function.

METHODS

Sprague-Dawley rats were subjected to controlled cortical impact injury (TBI). Sham animals underwent a similar surgery but no injury (SHAM). Animals were sacrificed 1, 3, and 7 days after TBI and intestinal smooth muscle tissue was collected for measurement of contractile activity and transit, NF-kB activity, and cytokine levels. Brains were collected after sacrifice to determine volume loss due to injury.

KEY RESULTS

Contractile activity decreased significantly in ileum, but not jejunum, in the TBI group 7 days after injury compared with SHAM. Brain volume loss increased significantly 7 days after injury compared with 3 days and correlated significantly with the contractile activity 1 day after injury. In the intestinal smooth muscle, NF-kB activity increased significantly in the TBI group 3 and 7 days after injury vs SHAM. Wet to dry weight ratio, indicating edema, also increased significantly in the TBI group. Interleukin-1α, -1β, and -17 increased significantly in the TBI group compared with SHAM.

CONCLUSIONS & INFERENCES

Traumatic brain injury causes a delayed but significant decrease in intestinal contractile activity in the ileum leading to delayed transit. The decreased intestinal contractile activity is attributed to secondary inflammatory injury as evidenced by increased NF-kB activity, increased edema, and increased inflammatory cytokines in the intestinal smooth muscle.

Changes in weight after traumatic brain injury in adult patients: a longitudinal study

BACKGROUND & AIMS

Although changes in weight have been reported after traumatic brain injury (TBI), their frequency and underlying factors are little known. Our aim was to determine the prevalence of weight changes and the associated factors during the recovery phase after TBI.

METHODS

Longitudinal follow-up of adults with TBI. Multivariate analysis was carried out on weight change, demographic data, dysexecutive syndrome, eating behavior, physical activity, therapeutic classes and metabolic complications.

RESULTS

107 patients (81 males/26 females), age 36 ± 13 yrs, baseline BMI 23.3 ± 3.9, followed for 38 (8-66) months, were included. In intensive care, patients lost a mean 11 ± 6 kg. End of follow-up, mean BMI was not different to pre-TBI BMI, but patients could be categorized in 3 groups: stable (30%), loss (28%, -8 ± 7 kg) and gain (42%, +9 ± 6 kg). Sex, age, severity of TBI, intensive care weight loss, physical activity, therapeutic classes and the occurrence of metabolic syndrome did not differ between the groups. Factors related to weight gain were hyperphagia, OR 4.5 (IC95%, 1.6-12.1) and presence of a dysexecutive syndrome, OR 2.5 (IC95%, 1.03-6.3). Factors related to weight loss were hypophagia, OR 4.1 (IC95%, 1.5-10.9) and higher pre-TBI BMI, OR 4.9 (IC95%, 1.7-14.0).

CONCLUSIONS

Over a median period of 38 months, 42% of TBI patients gained and 28% lost weight. Factors associated with these changes were the presence of a behavioral dysexecutive syndrome for weight gain, oral food intake and initial BMI, which were inversely associated with weight at end of follow-up. These findings highlight the importance of evaluating the time course of weight changes and providing specific nutritional care.

Nutritional support for patients sustaining traumatic brain injury: a systematic review and meta-analysis of prospective studies

Background

In traumatic brain injury (TBI), the appropriate timing and route of feeding, and the efficacy of immune-enhancing formulae have not been well established. We performed this meta-analysis aiming to compare the effects of different nutritional support modalities on clinical outcomes of TBI patients.

Methods

We systematically searched Pubmed, Embase, and the Cochrane Library until October, 2012. All randomized controlled trials (RCTs) and non-randomized prospective studies (NPSs) that compared the effects of different routes, timings, or formulae of feeding on outcomes in TBI patients were selected. The primary outcomes included mortality and poor outcome. The secondary outcomes included the length of hospital stay, the length of ventilation days, and the rate of infectious or feeding-related complications.

Findings

13 RCTs and 3 NPSs were included. The pooled data demonstrated that, compared with delayed feeding, early feeding was associated with a significant reduction in the rate of mortality (relative risk [RR] = 0.35; 95% CI, 0.24–0.50), poor outcome (RR = 0.70; 95% CI, 0.54–0.91), and infectious complications (RR = 0.77; 95% CI, 0.59–0.99). Compared with enteral nutrition, parenteral nutrition showed a slight trend of reduction in the rate of mortality (RR = 0.61; 95% CI, 0.34–1.09), poor outcome (RR = 0.73; 95% CI, 0.51–1.04), and infectious complications (RR = 0.89; 95% CI, 0.66–1.22), whereas without statistical significances. The immune-enhancing formula was associated with a significant reduction in infection rate compared with the standard formula (RR = 0.54; 95% CI, 0.35–0.82). Small-bowel feeding was found to be with a decreasing rate of pneumonia compared with nasogastric feeding (RR = 0.41; 95% CI, 0.22–0.76).

Conclusion

After TBI, early initiation of nutrition is recommended. It appears that parenteral nutrition is superior to enteral nutrition in improving outcomes. Our results lend support to the use of small-bowel feeding and immune-enhancing formulae in reducing infectious complications.

[Nutritional therapy in traumatic brain injury : Update 2012]

Severe traumatic brain injury ranks among the most common causes of death in young adults in western countries. Severe traumatic brain injury is typically followed by a pronounced pathophysiological cascade that accounts for many deaths. The aim of intensive care medicine after traumatic brain injury is to minimize and to control the consequences of this potentially fatal cascade. The avoidance of hypoxemia, arterial hypotension, intracranial hypertension, hyperthermia, hyperglycemia, hypoglycemia and thromboembolic complications is essential in preventing this cascade. The effect of nutrition has been rather underestimated as a means of improving the outcome after traumatic brain injury. Nutrition should be started within the first 24 h after trauma. Enteral, wherever applicable, should be the route of administration of nutrition. Enteral administration of the whole calculated calorie requirement on day 1 after trauma, if possible, lowers the infection and overall complication rates. The present review gives an update of a practical approach to nutrition in traumatic brain injury.

Energy expenditure in patients with severe head injury: controlled normothermia with sedation and neuromuscular blockade

OBJECTIVES

Providing optimal caloric intake is important for patients with severe traumatic brain injury. Insufficient nutrition worsens prognosis, and excessive nutrition may lead to complications such as weaning delay from mechanical ventilation. However, using controlled normothermia with sedation and neuromuscular blockade for patients with anticipated severe brain edema, the optimal caloric intake is still unclear.

METHODS

Ten patients with severe traumatic brain injury were studied. All patients received midazolam and vecuronium or pancuronium to control body temperature to 36.0°C. Energy expenditure was measured using indirect calorimetry. Age, body height, body weight, heart rate, blood pressure, body temperature, and minute ventilation volume were evaluated at the time of the study. Differences between the mean measured energy expenditures (MEEs) and predicted basal energy expenditures (PEEs from the Harris-Benedict equation) were analyzed using paired t test. Furthermore, the relationships between these variables and MEEs were analyzed with multiple regression analysis.

RESULTS

The result of MEE was 1279±244 kcal/d. When compared with PEE, MEE/PEE was 87.2% ± 10%. Multiple regression analysis showed that age, body height, body weight, heart rate, and minute ventilation volume were related with MEE.

CONCLUSIONS

Energy expenditure in patients with severe traumatic brain injury who need mechanical ventilation and have received controlled normothermia with sedation and neuromuscular blockade was 13% less than predicted basal levels. Energy expenditure might be obtained from age, body height, body weight, heart rate, and minute ventilation.

Description and prediction of resting metabolic rate after stroke and traumatic brain injury

OBJECTIVE

To compare the effect of stroke on the metabolic rate compared with the effect of traumatic brain injury and to determine whether the metabolic rate is predictable in both types of brain injury.

METHODS

Indirect calorimetry was conducted prospectively in mechanically ventilated patients within the first 6 d of admission to a critical care unit owing to ischemic stroke, hemorrhagic stroke, isolated traumatic brain injury, or traumatic brain injury with collateral injuries. Clinical data were collected simultaneously and a predicted value of the resting metabolic rate was calculated using the Penn State equation (using body size, body temperature, and minute ventilation).

RESULTS

One hundred thirty patients were measured. Ischemic stroke showed a lower incidence of fever, a lower body temperature, and a lower resting metabolic rate than the other groups; whereas in hemorrhagic stroke, these variables were similar to the trauma groups. Sedation decreased the resting metabolic rate, but this effect seemed particular to the trauma patients. The Penn State equation predicted the resting metabolic rate accurately 72% of the time, and when its component variables of body temperature and minute ventilation were controlled in an analysis of variance, all the differences among the brain injury and sedation groups were eliminated.

CONCLUSION

Stroke is a hypermetabolic event most of the time. Body size, temperature, and minute ventilation explain most of the variation in the resting metabolic rate after traumatic and non-traumatic brain injuries. The Penn State equation therefore predicts the resting metabolic rate in brain-injured patients no matter the mechanism of injury.

Ghrelin attenuates brain injury after traumatic brain injury and uncontrolled hemorrhagic shock in rats

Traumatic brain injury (TBI) and hemorrhagic shock often occur concomitantly due to multiple injuries. Gastrointestinal dysfunction occurs frequently in patients with TBI. However, whether alterations in the gastrointestinal system are involved in modulating neuronal damage and recovery after TBI is largely neglected. Ghrelin is a "gut-brain" hormone with multiple functions including antiinflammation and antiapoptosis. The purpose of this study was to determine whether ghrelin attenuates brain injury in a rat model of TBI and uncontrolled hemorrhage (UH). To study this, brain injury was induced by dropping a 450-g weight from 1.5 m onto a steel helmet attached to the skull of male adult rats. Immediately after TBI, a midline laparotomy was performed and both lumbar veins were isolated and severed at the junction with the vena cava. At 45 min after TBI/UH, ghrelin (4, 8 or 16 nmol/rat) or 1 mL normal saline (vehicle) was intravenously administered. Brain levels of TNF-α and IL-6, and cleaved PARP-1 levels in the cortex were measured at 4 h after TBI/UH. Beam balance test, forelimb placing test and hindlimb placing test were used to assess sensorimotor and reflex function. In additional groups of animals, ghrelin (16 nmol/rat) or vehicle was subcutaneously (s.c.) administered daily for 10 d after TBI/UH. The animals were monitored for 28 d to record body weight changes, neurological severity scale and survival. Our results showed that ghrelin downregulated brain levels of TNF-α and IL-6, reduced cortical levels of cleaved PARP-1, improved sensorimotor and reflex functions, and decreased mortality after TBI/UH. Thus, ghrelin has a great potential to be further developed as an effective resuscitation approach for the trauma victims with brain injury and severe blood loss.

Enteral nutrition in patients with severe traumatic brain injury: reasons for intolerance and medical management

Approximately, 50% of patients with severe traumatic brain injury (TBI) exhibit intolerance to enteral nutrition (EN). This intolerance hampers the survival and rehabilitation of this subpopulation to a great extent, and poses various difficulties for clinicians due to its complex underlying mechanisms. This review discusses the possible reasons for intolerance to EN following severe TBI, current trends in medical management, as well as other related issues that are experienced by many clinicians.

Nutritional support in head injury

Nutritional support is imperative to the recovery of head-injury patients. Hypermetabolism and hypercatabolism place this patient population at increased risk for weight loss, muscle wasting, and malnutrition. Nutrition management may be further complicated by alterations in gastrointestinal motility. Resting energy expenditure should be measured using indirect calorimetry and protein status measured using urine urea nitrogen. Providing early enteral nutrition within 72 hours of injury may decrease infection rates and overall complications. Establishing standards of practice and nutrition protocols will assure patients receive optimal nutrition assessment and intervention in a timely manner.