The effects of immune-enhancing diets (IEDs) on mortality, hospital length of stay, duration of mechanical ventilation, and other parameters

The Use of Specialized Enteral Formulas in Pulmonary Disease

The relationship between pulmonary disease and nutrition is significant. Malnutrition and its associated adverse pulmonary effects can directly affect outcomes in the individual with pulmonary disease. The use of nutrition support is common for these patients as a supportive or therapeutic measure. Historical reports of adverse respiratory function associated with high parenteral carbohydrate intakes have led to the controversial use of high-fat enteral products in patients with chronic pulmonary dysfunction. The rationale for using this type of formula is that by providing less carbohydrates, carbon dioxide production will be reduced, respiratory quotient will therefore decrease, and a favorable respiratory outcome will result. In the patient with acute respiratory distress syndrome, an inflammatory state exists in which proinflammatory mediators are produced and affect the course of the disease. An enteral formula with modified lipids designed to modulate eicosanoid production and therefore influence the inflammatory cascade is available. This article reviews the rationale for use of modified enteral formulas in both chronic and acute pulmonary disease, reviews the available studies evaluating the efficacy of these formulas, and provides overall recommendations for the use of specialized enteral formulas in individuals with pulmonary disease.

Obesity, inflammation, and the potential application of pharmaconutrition

Obesity is an emerging problem worldwide. Hospitalized obese patients often have a worse outcome than patients of normal weight, particularly in the setting of trauma and critical care. Obesity creates a low-grade systemic inflammatory response syndrome (SIRS) that is similar (but on a much smaller scale) to gram-negative sepsis. This process involves up-regulation of systemic immunity, is characterized clinically by insulin resistance and the metabolic syndrome, and puts the patient at increased risk for organ failure, infectious morbidity, and mortality. Through lipotoxicity and cytokine dysregulation, obesity may act to prime the immune system, predisposing to an exaggerated subsequent immune response when a second clinical insult occurs (such as trauma, burns, or myocardial infarction). Specialized nutrition therapy for such patients currently consists of a hypocaloric, high-protein diet. However, this approach does not address the putative pathophysiologic mechanisms of inflammation and altered metabolism associated with obesity. A number of dietary agents such as arginine, fish oil, and carnitine may correct these problems at the molecular level. Pharmaconutrition formulas may provide exciting innovations for the nutrition therapy of the obese patient.

Nutrition in critical illness

Malnutrition associated with critical illness has been unequivocally associated with increased morbidity and mortality in humans. Because malnutrition may similarly affect veterinary patients, the nutritional requirements of hospitalized critically ill animals must be properly addressed. Proper nutritional support is increasingly being recognized as an important therapeutic intervention in the care of critically ill patients. The current focus of veterinary critical care nutrition, and the major focus of this article, is on carefully selecting the patients most likely to benefit from nutritional support, deciding when to intervene, and optimizing nutritional support to individual patients.

Immune modulating nutrition support for a patient with severe toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare but serious condition with a high mortality rate, whose clinical features resemble major thermal injury. Nutritional substrates which can affect the immune response have been shown to benefit burned and critically ill patients but there is a lack of data in the TEN literature. A case study is presented of a 63-year-old female admitted to our burn unit with extensive skin and mucosal involvement. Immune modulating artificial nutrition support was given initially via the parenteral route and then the nasogastric route. Maintenance of the patient's nutritional status and clinical outcome suggest that there may be a role for this type of intervention in TEN.

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.

Nutritional support for the burn-injured patient

The nutritional needs of the bum-injured patient are exaggerated and change constantly with the patient's stage of convalescence. Nurses working closely with other members of the health care team, specifically the nutritional specialist, can positively affect the patient's survival by optimizing the nutritional assessment,delivering enteral feedings that meet established goals,minimizing the negative consequences of hyperglycemia, and minimizing unnecessary energy expenditures by the patient. Adequate nutritional is required for wound healing, immunocompetence, and, ultimately,patient survival.

Immune-enhancing diets for stressed patients with a special emphasis on arginine content: analysis of the analysis

PURPOSE OF REVIEW

After two decades of intensive research, whether arginine-enriched diets for oral/enteral administration are beneficial or harmful for stressed patients remains uncertain. An American consensus and a meta-analysis provide divergent conclusions. The main goal of the present review is to analyze these documents.

RECENT FINDINGS

The so-called immune-enhancing diets have been found to be beneficial to postoperative patients. Nothing proves, however, that arginine is responsible for these beneficial effects since immune-enhancing diets contain other pharmacologically active components (e.g. omega3 free fatty acids, RNAs, antioxidant vitamins). In fact, arginine-enriched diets may be harmful in hemodynamically unstable patients and those presenting with multiple organ failure.

SUMMARY

In light of the current doubts and until convincing data are produced, immune-enhancing diets should not be used in unstable critically ill patients.

Nutraceuticals: a pharmaceutical viewpoint: I

PURPOSE OF REVIEW

To review pharmaceutical aspects of selected amino acids, antioxidants and related nutraceuticals, deemed to be important for clinical nutrition.

RECENT FINDINGS

New clinical applications of nutraceuticals are increasingly being reported, but there are fundamental differences between formulation, production and the evidence supporting clinical use. Nutraceuticals generally fall within the novel foods and ingredients regulations but their purity, dosage requirements and clinical consequences exceed those of most 'healthfoods'. Replacement of one nutrient or antioxidant is unlikely to correct the cascade of interconnected metabolic abnormalities associated with many diseases. However, it is difficult to ascertain whether the reported benefits of complex mixtures, with little published stability data, are due to one or more individual substrates or some in-vitro interaction between them. Many clinical studies have suffered from inconsistencies of dose, formulation discrepancies and unproven outcome. These contradictory results weaken any firm evidence base to substantiate their effectiveness.

SUMMARY

Nutraceuticals are destined to play an important role in future therapeutic developments but their success will be governed by control of purity, safety and efficacy without inhibiting innovation. The straightforward application of pharmaceutical standards, especially across national borders, is likely to be a difficult challenge and could effectively paralyse the industry. Nevertheless more standardized formulations, dosage forms and production controls are called for. A place for nutraceuticals in clinical practice is emerging, but important pharmaceutical and clinical issues need to be addressed by further research.

Venilator Management and Criical Care Issues Following Cardiothoracic Trauma

Traumatic injury of the cardiac, pulmonary, or vascular systemsmay result in severe critical illness. Not only does the injury itself result in compromise of normal physiology, but initiation of the inflammatory cascade and mismanagement of the ventilator may lead to worsening status, the acute respiratory distress syndrome, and multiple organ dysfunction. Traumatic injury places the patient athigh risk of infection and nutritional compromise. We review basic concepts of mechanical ventilation and ventilator -associated or -induced lung injury. Barotrauma, volutrauma, atelectrauma and biotrauma, and methods for the clinician to prevent them, arediscussed. Airway pressure release ventilation, mandatory minute ventilation and adaptive support ventilation techniques are intro-duced, as is a discussion of the importance of spontaneous breathing during mechanical ventilation. Special attention is paid to a comprehensive approach to respiratory care. Unique modalities such as prone positioning, independent lung ventilation, and extracorporeal support are presented. The importance of adapting the mode or the minimal-injury concepts of mechanical ventilation to specific injuries is presented. Management approaches to these injuries, including ventilator therapy, pain control, surgical techniques, and critical care issues are described. An overview of the issues of infection inherent to trauma, and nutritional matters, including enteral versus parenteral therapy is presented. Immune-enhanced diets and antioxidantdrugs are integral components of the comprehensive approach to the trauma patient suffering critical illness, and pertinent literatureis summarized.

Should indirect calorimetry be used as part of nutritional assessment?

The use of indirect calorimetry in the design of nutritional support regimens is poorly appreciated by clinicians, who fail to recognize the importance of providing a sufficient volume of enteral feeding to critically ill patients. In contrast to the overfeeding that routinely occurred in the past with the provision of total parenteral nutrition, patients placed on the enteral route of support tend to be underfed because of problems with intolerance and frequent cessation. Clearly identifying and coming as close as possible to the caloric goal may be required to achieve the therapeutic endpoints of enteral tube feeding (which include maintenance of gut integrity, attenuation of the stress response, prophylaxis against stress-induced gastropathy, and stimulation of immune function). Indirect calorimetry is a convenient, accessible, and highly accurate instrument for the measurement of caloric requirements and is a valuable tool for the optimization of nutritional support in the intensive care unit.