Randomised trial of glutamine-enriched enteral nutrition on infectious morbidity in patients with multiple trauma.

BACKGROUND: Infections are an important cause of morbidity and mortality in patients with multiple trauma. Studies in both animals and human beings have suggested that glutamine-enriched nutrition decreases the number of infections. METHODS: Patients with multiple trauma with an expected survival of more than 48 h, and who had an Injury Severity Score of 20 or more, were randomly allocated glutamine supplemented enteral nutrition or a balanced, isonitrogenous, isocaloric enteral-feeding regimen along with usual care. Each patient was assessed every 8 h for infection, the primary endpoint. Data were analysed both per protocol, which included enteral feeding for at least 5 days, and by intention to treat. FINDINGS: 72 patients were enrolled and 60 received enteral feeding (29 glutamine-supplemented) for at least 5 days. Five (17%) of 29 patients in the glutamine-supplemented group had pneumonia compared with 14 (45%) of 31 patients in the control group (p<0.02). Bacteraemia occurred in two (7%) patients in glutamine group and 13 (42%) in the control group (p<0.005). One patient in the glutamine group had sepsis compared with eight (26%) patients in the control group (p<0.02). INTERPRETATION: There was a low frequency of pneumonia, sepsis, and bacteraemia in patients with multiple trauma who received glutamine-supplemented enteral nutrition. Larger studies are needed to investigate whether glutamine-supplemented enteral nutrition reduces mortality.

Predicting early nonelective hospital readmission in nutritionally compromised older adults.

This study determined predictors of early nonelective hospital readmission in 92 (49 women and 43 men) nutritionally compromised Medicare patients. Subjects ranged in age from 65 to 92 y and represented patients hospitalized previously for medical or surgical services. The study used a repeated-measures design of multiple variables representing demographics, anthropometric and clinical values, and functional status. Data were collected during hospitalization and during home visits at 1 and 3 mo postdischarge. There were 26 readmissions, making the 4-mo nonelective readmission rate 26%. Subjects who were readmitted nonelectively were compared with those not readmitted. Univariate analyses suggested strong relations between readmission outcome and serum albumin, total lymphocyte count, change in weight, and change in white blood cell count. Sociodemographic variables were less useful in predicting readmission than were measurements of patients' clinical status. Measurements of change in clinical variables were generally more predictive of readmission than was any one single measurement. Multivariate-logistic-regression analyses suggested a model consisting of change in weight and change in serum albumin from hospitalization to 1 mo after discharge as being highly predictive of early nonelective readmission. Individuals with any amount of weight loss and no improvement in albumin concentrations during the first month after hospitalization were at a much higher risk of readmission than were those who maintained or increased their postdischarge weight and had repleted their serum albumin concentrations. More study is warranted to clarify whether routine monitoring of changes in weight and serum albumin after hospitalization is appropriate in older adults.

Intestinal transit and absorption of soy protein in dogs depend on load and degree of protein hydrolysis.

Soy protein, in both intact and hydrolyzed forms, is widely used as the nitrogen source in infant and adult formulas. This protein is also consumed in vast quantities worldwide as soybean-based food products. Digestion is the rate-limiting step in the assimilation of proteins from the gut. As a result, intestinal transit must be slowed when a higher load of protein is available or when this nutrient is delivered in the intact rather than hydrolyzed form. However, little information is available on the effect of load and degree of hydrolysis of soy protein on intestinal transit and protein absorption. To test the hypothesis that inhibition of intestinal transit and protein absorption depend on the load of soy protein and the state of hydrolysis of this nutrient, we compared intestinal transit and protein absorption in dogs equipped with duodenal and midintestinal fistulas during intestinal perfusion with 0, 50, 100, or 200 g/L solutions of intact soy protein versus 0, 100, 200, 300, or 400 g/L solutions of hydrolyzed soy protein. We found that intestinal transit was slowed in a load-dependent fashion by intact (P < 0.001) and hydrolyzed (P < 0.05) soy protein. Soy protein inhibited intestinal transit more potently in the intact than hydrolyzed form (P < 0.05). A greater amount of protein was absorbed by the proximal half of the small intestine when soy protein was delivered in the hydrolyzed than intact form (P < 0.05), and the efficiency of protein absorption was maintained at a high and nearly constant level of 82.6 to 87.4% for intact soy protein and 89.0 to 92.3% for hydrolyzed soy protein. We conclude that in dogs intestinal transit and absorption of soy protein depend on the load and the degree of protein hydrolysis.

Protein absorption depends on load-dependent inhibition of intestinal transit in dogs.

Ileal perfusion of protein slows intestinal transit. Because optimal absorption of nutrients requires adequate time in contact with the mucosa, slowed intestinal transit may increase protein absorption by increasing the residence time of nutrients in the small intestine. Although protein supplements are routinely added to enteral feeding to correct protein malnutrition, little information is available on the effect of increasing the load of protein on intestinal transit and the efficiency of protein absorption. In six dogs equipped with duodenal and midintestinal fistulas, intestinal transit and the efficiency of protein absorption (percentage protein absorbed as estimated from the output of midintestinal fistula) were compared during intestinal perfusion with 0-, 50-, 100-, and 200-g/L solutions of a whey-based protein supplement. We found that intestinal transit slowed in a load-dependent fashion (P < 0.05); the amount of protein absorbed within the proximal one-half of the small intestine increased in a load-dependent fashion (P < 0.05) as intestinal transit slowed, and the percentage protein absorbed (reflecting the efficiency of protein absorption) was maintained at a high and nearly constant value of 66.5-72.5% across protein loads of 9-36 g. We conclude that enhanced protein absorption is associated with a load-dependent inhibition of intestinal transit.

Malnutrition and clinical outcomes: the case for medical nutrition therapy.

Malnutrition is not a new or a rare problem. In studies involving more than 1,327 hospitalized adult patients, 40% to 55% were found to be either malnourished or at risk for malnutrition, and up to 12% were severely malnourished. Surgical patients with likelihood of malnutrition are two to three times more likely to have minor and major complications as well as increased mortality; and their length of stay can be extended by 90% compared with the stay of well-nourished patients. Hospital charges are reported to be from 35% to 75% higher for malnourished patients than for well-nourished patients. Obtaining data to assess the nutritional status of patients is essential to optimal patient care, especially for patients at high risk for malnutrition. Nutrition assessment can be done with readily available and relatively inexpensive methods. But it is not enough to assess and identify malnutrition. Outcomes are improved and costs are saved only when appropriate intervention follows. This article identifies many well-conducted, published studies that support the findings that health outcomes of malnourished patients can be improved and that overall use of resources can be reduced by nutrition counseling, oral diet and oral supplements, enteral formula delivered via tube, and parenteral nutrition support via central or peripheral line. Early nutrition assessment and appropriate nutrition intervention must be accepted as essential for the delivery of quality health care. Appropriately selected nutrition support can address the problem of malnutrition, improve clinical outcomes, and help reduce the costs of health care.

Amino acid losses during hemodialysis: effects of high-solute flux and parenteral nutrition in acute renal failure.

BACKGROUND: During standard hemodialysis, amino acid losses are substantial, amounting to 6 to 9 g per treatment. When these nutritional supplements are infused during dialysis, losses are increased, but a net positive balance can be achieved if the infusion rate is high enough. High-flux dialyzers, used with increasing frequency in modern dialysis centers because of their more permeable synthetic membranes, should cause further amino acid losses; however, the increase has not been measured, and the effect on plasma levels has not been examined. Assessment of net balance requires measurement of blood concentrations as well as of clearance. METHODS: To quantitate the effect of high-flux dialysis on amino acid balance, we measured clearances, plasma levels, and losses of individual amino acids during hemodialysis in patients with acute renal failure who required daily parenteral nutrition. RESULTS: Nearly all predialysis amino acid levels in plasma were within the normal range, probably because of control of uremia with prior dialyses and from continuous infusion. In paired studies, clearances were higher (150 +/- 15 mL/min vs 107 +/- 11 mL/min, p < .01), and levels fell more at mid-dialysis with high-flux membranes (28% +/- 5%) than with conventional cellulosic membranes (4 +/- 5%, p < .05). Mean losses of amino acid were 5.2 +/- 0.6 g per conventional dialysis, representing 60% of the total infused, and 7.3 +/- 1.8 g per high-flux dialysis, or 80% of the simultaneous infusion. Fractional losses decreased at higher infusion rates, but losses of individual amino acids varied from one fourth to more than 10 times the amount infused. Compared with other small solutes, plasma levels were relatively well maintained even during high-flux dialysis, a factor that enhanced removal by the dialyzer. Total balance depended more on the infusion rate than on the dialysis membrane. CONCLUSIONS: These studies show that positive balance can be achieved with concurrent infusion during dialysis, especially at higher amino acid delivery rates. High-flux dialysis causes a greater disturbance of amino acid equilibrium than conventional dialysis does, but 24-hour gains far exceeded losses in the dialysate for most of the amino acids.

Long-term effects of early nutritional support with new enterotropic peptide-based formula vs. standard enteral formula in HIV-infected patients: randomized prospective trial.

Despite association with adverse clinical outcome, human immunodeficiency virus (HIV)-associated malnutrition has been relatively refractory to conventional nutrition management. Consequently, a prospective randomized trial was conducted to evaluate a new peptide-based enteral formula (NEF) in contrast to a standard enteral formula (SEF) in patients with HIV infection. Eighty early-stage largely asymptomatic patients were randomized into a dietary regimen supplemented with either a ready-to-feed NEF (18.7% protein, 65.5% carbohydrate, 15.8% fat; 1.28 kcal/ml) or SEF (14% protein, 55% carbohydrate, 31% fat; 1.06 kcal/ml). Patients received 2-3 8-oz cans of the NEF or SEF supplement per day for 6 mo. Parameters evaluated at 0 (baseline), 3, and 6 mo included adherence, weight change, anthropometric measurements, serum biochemical indices, gastrointestinal symptoms, physical performance, and intercurrent health events (including hospitalizations). For the 56 evaluable patients, those supplemented with NEF maintained their body weight significantly (p = 0.04) better, had significantly (p = 0.03) more stable triceps skin-fold measurements, and had significantly (p = 0.04) lower blood urea nitrogen than patients consuming the SEF supplement. Consumption of the NEF supplement was also associated with significantly reduced hospitalizations during the 3- to 6-mo evaluation period (p = 0.02). The NEF supplement was well tolerated and did not result in untoward clinical effects. These data suggest that supplemental use of an NEF provides superior nutritional management compared with an SEF for patients with early-stage HIV infection.

Enteral and parenteral nutrition support of terminally ill patients: practical and ethical perspectives.

The ethics of dealing with the provision of nutrition has been greatly complicated by technological advances. Seventy percent of all deaths in the United States include a decision to forgo some life-sustaining treatment including nutrition support. This article reviews ethical issues in nutrition support, appropriate and inappropriate nutrition support, practical information regarding provision of nutrition, and the development of institutional policies regarding artificial nutrition and hydration. Communication is emphasized in the process of establishing an ethically defensible consensus between patient and caregiver regarding withholding or withdrawing nutrition support. Within this context, withholding and withdrawing this support are considered to have the same ethical significance. Artificial nutrition and hydration is considered medical therapy and can be refused by competent patients and surrogates of incompetent patients under certain circumstances. Patient autonomy is emphasized as a guiding ethical principle.

Enteral nutrient solutions. Limiting bacterial growth.

Bacterial contamination of enteral nutrient solutions ( ENS ) in FFcess of food product standards is known to occur in the hospital setting. The large amounts of bacteria often given with ENS have been shown to create a reservoir for nosocomial infections, and nonpathogenic bacteria have been implicated. Patient tolerance is dependent on immune status and the bacterial load delivered to the gut. The purpose of this study was to evaluate the bacterial growth-sustaining properties of various ENS and to devise methods to limit bacterial growth. Five commercial products were prepared under sterile conditions. After inoculation with approximately 5 X 10(3) organisms/cm3 of Enterobacter cloacae, each solution was hung at room temperature for 24 hours with samples drawn at fixed intervals and plated for bacterial counts. Bacterial growth rates in Ensure, Travasorb , and Vital were markedly higher than those in Precision and Vivonex. Vivonex was noted to contain potassium sorbate (KS) used as a fungistatic agent. Recent studies have identified KS as a broad-spectrum bacteriostatic food preservative that is federally approved for this use. KS (0.03%) was added to Travasorb inoculated with 5 X 10(3) organisms/cm(3) of E. cloacae. The bacterial growth rate was reduced by 75 per cent, and the final count of 2-3 X 10(4) organisms/ml was within the federally regulated limit for milk. This study suggests that initial inoculum, growth rate, and hang time can be altered to provide a significant reduction in final bacterial counts in ENS .

Effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions.

Bacterial contamination and the effects of time, temperature, and preservative on bacterial growth in enteral nutrient solutions were studied. Bacteria were counted after 24-hour incubation of five samples of frozen Travasorb STD (Travenol Laboratories) from the pharmacy and five samples freshly reconstituted in the dietary department. Growth in samples of Travasorb STD prepared in the pharmacy was studied after (1) fresh mixing, 24-hour refrigeration, and 12 hours at room temperature, (2) freezing, thawing, and 12 hours at room temperature, and (3) freezing, thawing, 24-hour refrigeration, and 12 hours at room temperature. Duplicate samples of five products [Ensure (Ross Laboratories), Precision LR (Doyle Pharmaceuticals), Travasorb STD, Vital (Ross Laboratories), and Vivonex STD ( Norwich -Eaton)] were inoculated with Enterobacter cloacae, and growth curves for 24 hours were plotted. This challenge study was repeated using Travasorb STD as a control and Travasorb STD with potassium sorbate added. Bacterial contamination following reconstitution was not significantly different between pharmacy and dietary department samples. Growth after 12 hours at room temperature was not significantly different for the three sets of storage conditions. Logarithmic growth occurred only at room temperature. All products supported growth of E. cloacae, but growth was significantly lower in Vivonex STD (which contains potassium sorbate) and Precision LR. Growth was reduced by 70% versus control at 12 hours in Travasorb STD containing 0.036% potassium sorbate and by 90% with 0.2% potassium sorbate. Microbial growth in enteral nutrient solutions was dependent on the initial inoculum and the storage time at room temperature. Addition of potassium sorbate to these solutions may greatly reduce bacterial growth.

A test of the carbon-nitrogen balance technique to measure body composition of exercising animals.

Four randomly selected male Wistar rats were placed in separate metabolic chambers containing torqued Wahmann activity wheels. Quantitative collection of expired CO2, feces, and urine were carried out and the Carbon-Nitrogen balance technique was used to determine the changes in body composition of exercised animals during sequential, 48-hour periods. The behavioral contigency significantly increased running performance and weight gain. The weight of all body compartments, with the exception of body fat, increased significantly. Increased exercise significantly increased heat production. Sufficient data were gathered to permit discussion of individual animals and their adaptations and responses to the running contingencies.

Assessment of caloric needs in stressed patients.

An accurate assessment of the energy needs of hospitalized patients is necessary to fulfill caloric requirements, yet avoid inducing complications associated with excessive energy provisions. The objective of this study was to compare actual energy needs as determined by indirect calorimetry with several methods for estimating energy needs. These included the Harris-Benedict Equation (HBE), HBE plus factors for stress (ie, trauma, surgery, cancer), Wilmore 's nomogram, and estimates using 25 and 35 kcal/kg. One hundred nineteen parenteral nutrition patients were studied. HBE or the method of 25 kcal/kg was found to be most accurate in predicting energy needs. Stress factor adjustments of HBE significantly overestimated energy needs when compared to indirect calorimetry, as did the use of Wilmore 's nomogram and the factor of 35 kcal/kg.

Transurethral prostatic resection syndrome--a new perspective: encephalopathy with associated hyperammonemia.

Encephalopathy developed in 3 patients after transurethral prostatic resection. Each patient had blood ammonia levels more than 10 times the upper limit of normal. Data supportive of a metabolic cause for encephalopathy subsequently were obtained in a prospective study of patients undergoing transurethral prostatic resection with glycine irrigation. It is suggested that a distinct subpopulation of patients experiencing transurethral prostatic resection syndrome can be identified. These patients exhibit encephalopathic symptoms and have concurrent marked elevation of blood ammonia levels.