The use of immune enhancing diet in head injury

An oligomeric diet limits the response to injury in traumatic brain-injured rats

Adequate nutritional support is a major challenge in brain injury patients, because malnutrition cannot be reversed by standard enteral nutrition. We hypothesized that an oligomeric formula could improve nutritional status by restoring intestinal trophicity. Eighteen male Sprague-Dawley rats (300-330 g) underwent gastrostomy on day-7 (D-7) and traumatic brain injury (TBI) by hydraulic percussion (D0) and were then fed for 4 days with either a polymeric formula (Sondalis® HP, TBIP, n = 9), or an oligomeric formula (Peptamen® HN, TBIO, n = 9). In addition, a control group of healthy gastrostomized rats was fed the polymeric diet (control, n = 8). All rats were weighed daily. On D+4, the rats were euthanized. Blood was collected for plasma amino acid determination. Organs were removed and weighed. Intestinal morphometry was studied. Protein content was assessed on intestine and muscles. Enterobacterial translocation and dissemination were evaluated. Results were expressed as means ± SEM and compared using analysis of variance+Newman-Keuls test. TBI induced a significant decrease in whole body weight (TBIP vs. control, p < 0.05) that was totally blunted by the oligomeric diet (TBIP vs. TBIO, p < 0.01). Thymus weight significantly decreased after TBI (TBIP vs. control, p < 0.05) and was restored by the oligomeric formula (TBIO vs. TBIP, p < 0.05). Glutamine (GLN) concentration was improved by the oligomeric diet in both plasma (TBIO: 688 ± 19 vs. control: 591 ± 45 and TBIP: 615 ± 42 μmol/L, p < 0.05) and soleus muscle. These results show that the use of an oligomeric diet may limit response to injury after brain injury and could be a simple nutritional strategy in this setting.

Metabolic and nutritional support of the enterocutaneous fistula patient: a three-phase approach

BACKGROUND

The care and outcome of enterocutaneous fistula (ECF) have improved greatly over several decades due to revolutionary advances in nutrition, along with dramatic improvements in the treatment of sepsis and the critically ill. However, as the collective experience with damage control surgery has matured, the frequent development of enteroatmospheric fistula (EAF) in the "open abdomen" patient has emerged as an even more vexing problem. Despite our best efforts, ECF and especially EAF continue to be highly morbid conditions, and sepsis and malnutrition remain the leading causes of death. Aggressive nutritional and metabolic support is the most significant predictor of outcome with ECF and EAF.

RESULTS

Discussion of the historical advances in nutritional therapy and their impact on ECF, as well as review of the classification of ECF and EAF, provides a framework for the suggested phased strategy that specifically targets the nutritional and metabolic needs of the ECF/EAF patient. These three phases include (1) diagnosis, resuscitation, and early interval nutrition; (2) definition of fistula anatomy, drainage of collections, nutritional assessment and monitoring, and placement of feeding access; and (3) definitive nutritional management, including pharmacologic adjuncts. Early nutritional support with parenteral nutrition followed by transition to enteral nutrition is advocated, including the merits of delivery of enteral nutrition via the fistula itself, known as fistuloclysis.

CONCLUSION

Aggressive nutritional therapy is necessary to reverse the catabolic state associated with ECF/EAF patients. Once established, it allows proper time, preparation, and planning for definitive management of the fistula, and in many cases provides the support for spontaneous closure.

Arginine-enriched diet limits plasma and muscle glutamine depletion in head-injured rats

OBJECTIVE

Injury is associated with a depletion in glutamine (GLN) pools, which may contribute to impairment of immune and nutritional statuses. Total parenteral nutrition enriched with arginine (ARG) is able to generate GLN in surgical patients. We hypothesized that this same concept may be applicable to enteral administration and could be extended to muscle GLN reserves. This study investigated the ability of an enteral formula enriched with ARG to restore the GLN pools in an experimental model of head injury.

METHODS

Twenty-five male Sprague-Dawley rats were randomized into 4 groups: ad libitum access to food, head injury plus free access to nutrition, head injury plus standard enteral nutrition (Sondalis), and an immune-enhancing diet (IED). The two enteral diets were adjusted to be isocaloric (290 kcal.kg(-1).d(-1)) and isonitrogenous (3.29 g.kg(-1).d(-1)) and were delivered for 4 d (24 h/24 h). After sacrifice, plasma and muscle amino acids were determined.

RESULTS

Head injury was associated with a large depletion of muscle and plasma GLN pools that were restored by IED administration but not by the standard diet. Moreover, the IED but not the standard diet improved or normalized ornithine and glutamate pools, suggesting that the modification of GLN pools is related to ARG administration.

CONCLUSION

In our model of head injury, our IED, a diet without free GLN, is efficient in restoring the plasma and muscle pools of GLN, probably due to its high ARG content.

Guidelines for nutritional support in intensive care unit patients: a critical analysis

PURPOSE OF REVIEW

Guidelines are supposed to be helpful in clinical practice. Guidelines are also supposed to rest upon the evidence that there is. In the field of clinical nutrition the problem is that many clinical trials are not conclusive because they are underpowered and sometimes have an inferior design.

RECENT FINDINGS

The publication of the Canadian guidelines one year ago initiated a lively debate. The Canadian guidelines used meta-analysis as a tool to review the literature. This resulted in both a sound evaluation of studies as well as some controversial recommendations. The Canadian guidelines are here put in a perspective in which the older type of guidelines are compared, and some of the points of recommendation are scrutinized.

SUMMARY

What all guidelines agree upon is the shortage of solid knowledge, the conviction that complications related to nutritional therapy in the intensive care unit are not acceptable, and that enteral nutrition is preferable if it can be given without risk. Beyond that, many controversies remain and the need for high quality prospective studies must be emphasized. In addition, such studies must address the clinically important questions that the guidelines try to answer.

Characterization of the alteration of nutritional state in brain injury induced by fluid percussion in rats

OBJECTIVE

Patients suffering from traumatic brain injury (TBI) undergo rapid weight loss with negative nitrogen balance and enhanced whole-body protein breakdown, with protein wasting causing morbidity and increased mortality. Many experimental models of TBI have been used to evaluate strategies to improve the outcome of these patients, but nutritional status has not been considered in experiments published to date, although this may have great importance and influence the results obtained with TBI models. This study characterized the hypercatabolism level and nutritional status of TBI rats.

DESIGN

Twenty-four male Wistar rats were randomized into three groups. Rats from the TBI group were anesthetized and fluid percussion was applied. The pair-fed (PF) group was healthy but was pair-fed to the TBI group. The ad libitum (AL) group was healthy and fed ad libitum. The study was performed over 10 days post-TBI.

MEASUREMENTS AND RESULTS

TBI in rats was characterized by remarkable long-lasting anorexia, renal failure (creatinine clearance: AL 1.8+/-0.2 and PF 1.5+/-0.1 vs. TBI 0.9+/-0.1 l/24 hour), anorexia (appetite depressed throughout the study), increased myofibrillar proteolysis (3-methylhistidine/creatinine ratio (day 2: AL 36+/-1 and PF 38+/-2 vs. TBI 54+/-5 micromol/mmol), and intestinal atrophy (ileum: AL 29.3+/-2.5 and PF 28.7+/-1.1 vs. TBI 22.5+/-1.4 mg/cm). In addition, anorexia led to muscular atrophy and decreased nitrogen balance. The metabolic alterations described above can increase morbidity and mortality.

CONCLUSIONS

TBI by fluid percussion in rats is a model reproducing the metabolic and nutritional alterations observed in clinical practice and is suitable for further studies exploring the efficacy of optimized nutritional support.