Nutritional support for head-injured patients

Comprehensive Profile of Acute Mitochondrial Dysfunction in a Preclinical Model of Severe Penetrating TBI

Mitochondria constitute a central role in brain energy metabolism, and play a pivotal role in the development of secondary pathophysiology and subsequent neuronal cell death following traumatic brain injury (TBI). Under normal circumstances, the brain consumes glucose as the preferred energy source for adenosine triphosphate (ATP) production over ketones. To understand the comprehensive picture of substrate-specific mitochondrial bioenergetics responses following TBI, adult male rats were subjected to either 10% unilateral penetrating ballistic-like brain injury (PBBI) or sham craniectomy (n = 5 animals per group). At 24 h post-injury, mitochondria were isolated from pooled brain regions (frontal cortex and striatum) of the ipsilateral hemisphere. Mitochondrial bioenergetics parameters were measured ex vivo in the presence of four sets of metabolic substrates: pyruvate+malate (PM), glutamate+malate (GM), succinate (Succ), and β-hydroxybutyrate+malate (BHBM). Additionally, mitochondrial matrix dehydrogenase activities [i.e., pyruvate dehydrogenase complex (PDHC), alpha-ketoglutarate dehydrogenase complex (α-KGDHC), and glutamate dehydrogenase (GDH)] and mitochondrial membrane-bound dehydrogenase activities [i.e., electron transport chain (ETC) Complex I, II, and IV] were compared between PBBI and sham groups. Furthermore, mitochondrial coenzyme contents, including NAD_(t) and FAD_(t), were quantitatively measured in both groups. Collectively, PBBI led to an overall significant decline in the ATP synthesis rates (43-50%; ^* p < 0.05 vs. sham) when measured using each of the four sets of substrates. The PDHC and GDH activities were significantly reduced in the PBBI group (42-53%; ^* p < 0.05 vs. sham), whereas no significant differences were noted in α-KGDHC activity between groups. Both Complex I and Complex IV activities were significantly reduced following PBBI (47-81%; ^* p < 0.05 vs. sham), whereas, Complex II activity was comparable between groups. The NAD_(t) and FAD_(t) contents were significantly decreased in the PBBI group (27-35%; ^* p < 0.05 vs. sham). The decreased ATP synthesis rates may be due to the significant reductions in brain mitochondrial dehydrogenase activities and coenzyme contents observed acutely following PBBI. These results provide a basis for the use of "alternative biofuels" for achieving higher ATP production following severe penetrating brain trauma.

Evidence-based position paper on Physical and Rehabilitation Medicine professional practice for Adults with Acquired Brain Injury. The European PRM position (UEMS PRM Section)

BACKGROUND

Acquired brain injury (ABI) is damage to the brain that occurs after birth caused either by a traumatic or by a nontraumatic injury. The rehabilitation process following ABI should be performed by a multi-professional team, working in an interdisciplinary way, with the aim of organizing a comprehensive and holistic approach to persons with every severity of ABI. This Evidence Based Position Paper represents the official position of the European Union through the UEMS Physical and Rehabilitation Medicine (PRM) Section and designates the professional role of PRM physicians for people with ABI. The aim was to formulate recommendations on the PRM physician's professional practice for persons with ABI in order to promote their functioning and enhance quality of life.

METHODS

This paper has been developed according to the methodology defined by the Professional Practice Committee of the UEMS-PRM Section: a systematic literature search has been performed in PubMed and Core Clinical Journals. On the basis of the selected papers, recommendations have been made as a result of five Delphi rounds.

RESULTS

The literature review as well as thirty-one recommendations are presented.

CONCLUSIONS

The expert consensus is that structured, comprehensive and holistic rehabilitation program delivered by the multi-professional team, working in an interdisciplinary way, with the leadership and coordination of the PRM physician, is likely to be effective, especially for those with severe disability after brain injury.

The impact of measurement of respiratory quotient by indirect calorimetry on the achievement of nitrogen balance in patients with severe traumatic brain injury

BACKGROUND

This study evaluated the impact of IC on the optimization of nutritional support and the achievement of +NB in patients with TBI.

MATERIALS AND METHODS

27 patients (GCS ≤ 8), treated with a 5-day multimodality monitoring and goal-directed therapy protocol, received enteral nutrition on day 1 followed by IC on days 3 and 5 and assessment of NB on day 7. In the first cohort (n = 11), no adjustment in kcal was made. In the second cohort (n = 16), nutrition was targeted to an RQ of 0.83 by day 3. The first cohort was analyzed with respect to NB status; the second cohort was compared to patients with (-) and +NB of the first cohort. Data (mean ± SD) were analyzed with unpaired t test, and Chi square and Fisher exact tests.

RESULTS

4/11(36 %) patients in the first cohort had +NB. The predicted mortality by TRISS, substrate utilization, and RQ was significantly lower compared to the second cohort. The mortality predicted by the CrasH model did not differ between the two cohorts. A RQ of 0.74 was associated with the preferential use of fat and protein and -NB, whereas a RQ of 0.84 favored utilization of carbohydrates and +NB. All patients whose kcal intake was adjusted based on the RQ on day 3 reached a +NB by day 7.

CONCLUSION

An increase in kcal ≥25 % in patients with a RQ < 0.83 on day 3 improves substrate utilization, decreases protein utilization and optimizes the achievement of +NB by day 7.

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 prognostic significance of the timing of total enteral feeding in traumatic brain injury

BACKGROUND

To study the effect of timing of total enteral feeding on various nutritional parameters and neurological outcome in patients with severe traumatic brain injury (TBI).

METHODS

One hundred and fourteen patients, in the age group of 20-60 years, admitted within 24 h of TBI with Glasgow Coma Scale (GCS) 4-8 were enrolled for the study. Nineteen patients who had expired before the attainment of total enteral feeding were excluded from the analysis. Total enteral feeding was attained before 3 days, 4-7 days, and after 7 days in 12, 52, and 31 patients, respectively, depending on gastric tolerance. They were prospectively assessed for various markers of nutrition and outcome was assessed at 3 and 6 months.

RESULTS

Prospective assessment of 67 hospitalized patients at 3 weeks revealed significant differences in anthropometric measurements, total protein, albumin levels, clinical features of malnutrition, and mortality among the three groups. 80% of those fed before 3 days had favorable outcome at 3 months compared to 43% among those fed later. The odds ratio (OR) was 5.29 (95% CI 1.03-27.03) and P value was 0.04. The difference between those fed before 3 days and 4-7 days was not significant at 6 months even though patients fed before 7 days had still significantly higher favorable outcome compared to those fed after 7 days (OR 7.69, P = 0.002). Multivariate analysis for unfavorable outcome showed significance of P = 0.03 for feeding after 3 days and P = 0.01 for feeding after 7 days.

CONCLUSIONS

In severe TBI, unfavorable outcome was significantly associated with attainment of total enteral feeding after 3 days and more so after 7 days following injury.

Severe head injury: clinicians' awareness of the literature

OBJECTIVES

1. To determine the awareness of the literature concerning therapeutic manoeuvres in severe closed head injury (CHI) among Canadian critical care clinicians and neurosurgeons, 2. To identify factors that affect utilization of these manoeuvres, and 3. To compare reported appropriateness and frequency of use with #1 and #2.

METHODS

The study design was a systematic scenario-based survey of all neurosurgeons and critical care physicians treating patients with severe CHI in Canada.

RESULTS

Fifty-nine of 99 neurosurgeons and 82 of 148 critical care physicians responded (57%). The majority of respondents were not able to identify the highest level of published evidence for most manoeuvres, except for the avoidance of corticosteroids (51%). The factor identified by most respondents as being most important in motivating use of any given manoeuvres was the level of published evidence (25%). Although reported appropriateness and frequency of use of most manoeuvres correlated well with each other, they did not correlate with awareness of evidence. In the case of corticosteroids, there was a strong correlation between non-use of steroids and awareness of evidence (R = -0.30, p = 0.0003).

CONCLUSIONS

Respondents to this survey of Canadian physicians treating patients with severe head injury reported published evidence as being the most significant factor affecting use of a therapy. However, most respondents did not correctly identify the highest published level of evidence for most therapies. This study has identified difficulty with research translation that may have clinical implications.

Review of the pathophysiology and management of postoperative ileus

Investigations in the pathophysiology and treatment of postoperative ileus continue to evolve. Bowel rest is no longer a mandatory component of postoperative recovery. Tolerance of enteral nutrition and normalization of the abdominal examination are more accurate indications of the resolution of postoperative ileus than passage of flatus or first bowel movement. A multimodal "fast track" recovery approach incorporated into a clinical pathway provides a more rapid return of intestinal function and shortened hospital stay in patients undergoing major, uncomplicated gastrointestinal surgery.

Preliminary Evidence for a Medical Nutrition Therapy Protocol: Enteral Feedings for Critically Ill Patients

The objective of this study was to evaluate the evidence behind specific but common patient care decisions in support of enteral feedings for patients admitted to intensive care units. Six specific questions were developed and refined to address clinical outcomes specific to clinical practice decisions pertinent to enteral feeding of critically ill patients. The data sources consisted of an intensive literature review from five databases, using standardized search terms. Randomized controlled clinical trials, meta-analyses, consensus statements, reviews, US Food and Drug Administration alerts, and case reports were selected for study. Research reports were abstracted in detail and evaluated for research quality using the criteria developed by the American Dietetic Association. Consensus statements regarding the influence of specific enteral feeding methods on key clinical outcomes (ie, infectious complications, cost, length of hospital stay, and mortality) were developed and graded based on the quality of the available evidence. The data support the use of enteral over parenteral nutrition to reduce infectious complications and cost, and the initiation of enteral feedings within 24 to 48 hours of injury or admission to an intensive care unit to reduce infectious complications and length of hospital stay in head injury and trauma patients. Postpyloric tube placement is associated with reduced gastric residual volume and reflux, but adequately powered trials are not available to support prevention of aspiration pneumonia. Acceptance of gastric residual volumes of up to 250 mL may increase volume of formula delivered. Promotility agents are associated with reduced gastric residual volume. Feeding patients in the semirecumbent rather than supine position is associated with reduced aspiration pneumonia and pharyngoesophageal formula reflux. Actual delivery of 14 to 18 kcal/kg/day or 60% to 70% of goal is associated with improved outcomes, whereas greater intake may not be in some populations. Blue food coloring should not be used with enteral feedings due to its limited sensitivity for aspiration and some risk of mortality. Well-designed, adequately powered, randomized controlled clinical trials are needed to evaluate any benefit of tube tip position on aspiration pneumonia or mortality, and of early enteral feedings on mortality.

Evidence-based clinical practice: dispelling the myths

Evidence-based practice merges the best and most relevant clinical research data with clinician experience, pathophysiology of disease state, and the specifics of individual patient care. Currently, there is a significant gap between the best research evidence in healthcare and application of this evidence to clinician practices. Consistent with this finding, nutrition support is not always applied effectively or consistently, despite available scientific evidence that could be used to enhance a given treatment protocol. Cited obstacles that prevent the incorporation of research evidence into daily practice include lack of time, inadequate research skills, and information overload. Identification and application of the most valid primary research and evidence summaries (clinical guides to practice and meta-analyses) should, however, be an integral part of appropriate nutrition care. Consequently, it is important that clinicians develop and improve upon the basic skills required to allow efficient and accurate searches and evaluations of the literature. This review describes the basic and practical components of evidence-based medicine and provides tools to determine whether current nutrition practices are based upon an analysis of valid clinical evidence or anecdotal nutrition traditions and myths.

Nosocomial infections and immunity: lesson from brain-injured patients

Of brain-injured patients admitted to intensive care units, a significant number acquires nosocomial infections. Increased susceptibility to infectious agents could, at least partly, be due to transient immunodepression triggered by brain damage. Immune deficiency in patients with severe brain injury primarily involves T cell dysfunction. However, humoral and phagocytic deficiencies are also detectable. Activation of the hypothalamo-pituitary-adrenal axis and the sympathetic nervous system plays a crucial role in brain-mediated immunodepression. In this review we discuss the role of immunodepression in the development of nosocomial infections and clinical trials on immunomodulation in brain-injured patients with hospital-acquired infections.