A physiologic basis for the provision of fuel mixtures in normal and stressed patients

Modular protein supplements and their application to long-term care

Modular protein supplements are added to either the diet or enteral formula to increase the protein or amino acid intakes of people who are nutritionally compromised. Protein supplements are aggressively marketed to long-term care clinicians because protein energy malnutrition and wounds are a common problem in this care setting. It can be challenging for clinicians to distinguish one product from another and to determine the best product for a specific application or nutrition care goal. Modular protein products can be sorted into 4 categories: (1) protein concentrates derived from a complete protein such as milk, soy, or eggs; (2) protein concentrates derived from collagen, either alone or in combination with a complete protein; (3) doses of 1 or more dispensable (nonessential) amino acids; and (4) hybrids of the complete or collagen-based proteins and amino acid dose. Modular protein supplements are generally provided either as a substrate for protein synthesis or as a source of 1 or more amino acids that may be conditionally indispensable (conditionally essential) under certain disease conditions. This review provides guidelines for the use of modular protein supplements according to their intended physiologic function and the assessment and nutrition care goals of the long-term care resident.

Prevention and Treatment of Pressure Ulcers

Pressure ulcers are complex chronic wounds for which no gold standard for prevention or treatment has yet been established. Several attempts at developing guidelines has been undertaken by different organizations. Pressure ulcers are devastating comorbidities for patients and difficult to prevent or manage. Whether or not pressure ulcers are preventable remains controversial. The strategy for prevention includes recognizing the risk, decreasing the effects of pressure, assessing nutritional status, avoiding excessive bed rest and prolonged sitting, and preserving the integrity of the skin. The principles of treatment of pressure ulcers include assessing severity, reducing pressure, friction and shear forces, optimizing local wound care, removing necrotic debris, managing bacterial contamination, and correcting nutritional deficits.

Clinical and metabolic effects of two lipid emulsions on the parenteral nutrition of septic patients

OBJECTIVE

We compared the metabolic and clinical effects of two lipid emulsions, long-chain triacylglycerols (LCT) and a mixture of medium- and long-chain triacylglycerols (MCT/LCT), in septic patients.

METHODS

Both groups received total parenteral nutrition (TPN) with a solution enriched with branched-chain amino acids (BCAA). Seventy-two septic patients received TPN with MCT/LCT (group 1) or LCT (group 2). Before starting TPN (basal) and 10 d after (final), various parameters were evaluated.

RESULTS

Twenty-six subjects in each group completed the study. Both groups showed an increase in cholestasis enzymes, with no significant changes in lipid parameters. The rise of retinol-binding protein and the recovery of nitrogen balance were significantly greater in group 1. A multivariate analysis of nutritional markers and catabolic parameters showed a better evolution in group 1 (P = 0.002). The MCT/LCT group exhibited a significant increase of insulin levels. Overall mortality and length of stay in the intensive care unit were not affected by the lipid emulsion.

CONCLUSIONS

In septic patients who received TPN with a solution enriched with BCAAs, the use of an emulsion containing MCT provided them with a greater recovery of their nutrition status than the traditional LCT formula, without influencing the outcome.

The erythromycin breath test for the prediction of drug clearance

The erythromycin breath test (EBT) is a putative probe of cytochrome P450 (CYP) 3A4 activity in vivo. Therefore, the EBT might prove useful for the individualisation of doses of drugs that have a low therapeutic window (for example the immunosuppressants or cytotoxics) and are metabolised by CYP3A4. However, there is a lack of consensus as to how the EBT should be used to predict total body clearance (CL), and the results so far have been largely disappointing. We argue that the required assumption that individuals produce 5 mmol of CO2/min per m2 at rest is one of the problems with the existing EBT, as the literature suggests significant variability and possible gender differences in this parameter. An examination of the EBT with a simple compartment model suggests that alternative parameters could be more useful in the prediction of CL. In particular, there is theoretical support for the use of the time-point at which breath radioactivity is maximal (tmax) as a correlate for CL. This is in agreement with our recent study of the pharmacokinetics of erythromycin in patients with cancer.

Issues and dilemmas in the prevention and treatment of pressure ulcers: a review

Considerable dogma and rhetoric, rather than evidence-based results, have accompanied recommendations for the prevention and treatment of pressure ulcers. Therapy for pressure ulcers is generally empiric, based on anecdotal experience, or borrowed from the treatment of patients with acute wounds. The treatment of pressure ulcers is problematic because of multiple comorbidities of patients, the chronic duration of pressure ulcers, and often by the physician's relative unfamiliarity with treatment options. Issues and dilemmas in the prevention of pressure ulcers center around risk assessment, means of pressure relief, and nutritional support. Similar issues in the treatment of pressure ulcers include implementing pressure relief, nutritional support, local wound care, the best method of debridement, diagnosing infection, the use of topical growth factors, and surgical treatment. The accumulating data for the prevention and management of pressure ulcers permits an outline of clinical strategies.

Improving outcome of pressure ulcers with nutritional interventions: a review of the evidence

Pressure ulcers and malnutrition frequently co-exist in frail patients. Nutritional parameters have been correlated with development and with healing in chronic pressure ulcers, leading to suggestions that improving nutritional status can prevent or treat pressure ulcers. Despite a strong association, a causal relationship of poor nutritional status to development of pressure ulcers has not been established. Support for a causal relationship would include evidence that nutritional interventions improve general nutritional status, acute wound healing, or chronic wound healing. The data suggesting that nutritional intervention can improve clinical outcome are limited. No study has demonstrated that improvement in nutritional status can prevent pressure ulcers. There is at least suggestive evidence that improvement in nutritional status can improve outcome in pressure ulcer healing.

Wound management in postacute care

Decreasing hospital length of stay has dictated that postacute and long-term care facilities bear the brunt of treating acute and chronic wounds. Two types of chronic wounds are discussed: (1) pressure ulcers and (2) diabetic ulcers. The differential diagnosis of these ulcers is imperative because the management of both types of wound differs substantially. Wound therapy includes relieving pain, correcting nutritional deficiencies, maintaining an optimal wound environment, shielding the wound from further damage, removing necrotic debris, promoting granulation tissue formation, protecting against bacterial contamination, choosing an appropriate dressing, and surgical treatment. The application of these principles is discussed, and the differences among wound types are highlighted.

The role of nutrition in prevention and healing of pressure ulcers

Among the many risk factors for pressure ulcers, malnutrition is potentially reversible. This article examines the relationship of malnutrition to the prevention and healing of pressure ulcers. Evidence for nutrition in preventing and healing pressure ulcers is presented. Specific nutrients, including some amino acids, vitamins, and minerals, have been evaluated for their effects on wound healing.

Copper, selenium, and zinc status and balances after major trauma

To investigate the trace elements (TE) losses and status after trauma, 11 severely injured patients (Injury Severity Score: 29 +/- 6), admitted to the ICU were studied from the day of injury (D0) until D25. Balance studies were started within 24 hours after injury, until D7. Serum and urine samples were collected from D1 to D7, then on D10, 15, 20, and 25. Intravenous TE supplementation was initiated upon admission. SERUM: Selenium (Se) and zinc (Zn) levels were decreased until D7 and were normal thereafter. LOSSES: TE urinary excretions were higher than reference ranges until D20 in all patients. Fluid losses through drains contained large amounts of TE. BALANCES: Balances were slightly positive for copper (Cu) and Zn, and negative for Se from D5 to D7 despite supplements. Cu status exhibited minor changes compared to those observed with the Zn and Se status: Serum levels were decreased and losses increased. Considering the importance of Se and Zn in free radical scavenging, anabolism, and immunity, current recommendations for TE supplements in severely traumatized patients ought to be revised.

Short-term energy balance in patients with infections: carbohydrate-based versus fat-based diets

The effects of a carbohydrate-based diet (50% carbohydrate calories, 30% fat calories, 20% protein calories) versus a fat-based diet (28% carbohydrate calories, 55% fat calories, 17% protein calories) on oxidation rates of carbohydrate, fat, and protein were assessed in 12 patients with infections by indirect calorimetry and estimation of urea nitrogen production rate. The diets were given continuously for 18 hours in a randomized cross-over study on 2 consecutive days. Energy supply (kcal/d) was adjusted individually to meet the energy expenditure measured on the preceding day after an overnight fast and was 1,647 +/- 129 (SEM) for the carbohydrate-based diet and 1,655 +/- 131 for the fat-based diet. Oxidation rates (kcal/d) for carbohydrate (carbohydrate-based diet, 525 +/- 70; fat-based diet, 363 +/- 84) were different between the diets (P less than .05), whereas no difference could be found for fat (carbohydrate-based diet, 820 +/- 117; fat-based diet, 968 +/- 136) and protein (carbohydrate-based diet, 252 +/- 29; fat-based diet, 236 +/- 23). However, during carbohydrate-based feeding, carbohydrate balance (288 +/- 93 kcal/d) and fat balance (-327 +/- 107 kcal/d) were significantly different from zero (P less than .05), indicating continuous oxidation of endogenous fat and storage of administered glucose. During the fat-based diet, carbohydrate and fat balances were not different from zero. A correlation between energy and substrate balances was not seen during either diet.(ABSTRACT TRUNCATED AT 250 WORDS)