Parenteral nourishment of patients undergoing surgical or traumatic stress

Longitudinal assessment of growth in hypoplastic left heart syndrome: results from the single ventricle reconstruction trial

BACKGROUND

We sought to characterize growth between birth and age 3 years in infants with hypoplastic left heart syndrome who underwent the Norwood procedure.

METHODS AND RESULTS

We performed a secondary analysis using the Single Ventricle Reconstruction Trial database after excluding patients <37 weeks gestation (N=498). We determined length-for-age z score (LAZ) and weight-for-age z score (WAZ) at birth and age 3 years and change in WAZ over 4 clinically relevant time periods. We identified correlates of change in WAZ and LAZ using multivariable linear regression with bootstrapping. Mean WAZ and LAZ were below average relative to the general population at birth (P<0.001, P=0.05, respectively) and age 3 years (P<0.001 each). The largest decrease in WAZ occurred between birth and Norwood discharge; the greatest gain occurred between stage II and 14 months. At age 3 years, WAZ and LAZ were <-2 in 6% and 18%, respectively. Factors associated with change in WAZ differed among time periods. Shunt type was associated with change in WAZ only in the Norwood discharge to stage II period; subjects with a Blalock-Taussig shunt had a greater decline in WAZ than those with a right ventricle-pulmonary artery shunt (P=0.002).

CONCLUSIONS

WAZ changed over time and the predictors of change in WAZ varied among time periods. By age 3 years, subjects remained small and three times as many children were short as were underweight (>2 SD below normal). Failure to find consistent risk factors supports the strategy of tailoring nutritional therapies to patient- and stage-specific targets.

CLINICAL TRIAL REGISTRATION URL

http://clinicaltrials.gov/. Unique identifier: NCT00115934.

Nutritional management of patients with gastrointestinal fistulas

Nutritional support plays a key and integral role in the management of patients with gastrointestinal fistulas. It needs to be instituted early to minimize erosion of body cell mass, to prevent further physiologic deterioration of the patient, and to initiate repletion in an otherwise malnourished patient. Furthermore, it allows for rest of the gastrointestinal tract and facilitates healing of the fistula.

Nutrition support in specific diseases: back to basics

The nutrition care of a patient is complicated by the recent proliferation of commercially available specialty products. Rational and objective guidelines are necessary to direct formula selection for use in specific diseases. Consideration of the patient's nutritional status, functioning of major organ systems, and alterations in nutrient metabolism are essential. The diagnosis of a specific disease does not necessitate the use of a specialty product in all instances. Many times modification of a standard formula can result in safe and effective nutrition. Basic nutrition principles should continue to guide the clinician as the definitive answers to the issues surrounding metabolic support in patients with specific disease states become available.

Parenteral nutrition for marrow transplant recipients: evaluation of an increased nitrogen dose

The use of total parenteral nutrition in bone marrow transplant (BMT) recipients is well recognized. These patients as a result of treatment with chemotherapy and immunosuppressive agents undergo catabolic stress. The metabolic effect of an increased nitrogen dose during total parenteral nutrition (TPN) was studied in 28 BMT patients. Patients were given TPN formulas providing a nitrogen intake of either 267 +/- 44 mg of N/kg/d or 330 +/- 60 mg of N/kg/d. Total calories, nonprotein and protein, were held constant at 40 kcal/kg/d for all patients. Data was collected for three periods posttransplant beginning at 3 days posttransplant through day 16. Both study TPN formulas improved patient weight and TIBC values over baseline. Nitrogen balance (NB) values were not significantly different at any study period. However, an overall group effect favored the H-N formula (p less than 0.01). BMT patients undergo catabolic stress which was reflected by average values of 24-hour urine urea nitrogen increasing from 8.1 +/- 4 g/d at baseline to 19.8 +/- 7.2 g/d at period 3 (p less than 0.01). The H-N formula did not differentially increase blood urea nitrogen or serum creatinine levels. Metabolic cart measures also showed no increase in metabolic rate, oxygen consumption, carbon dioxide production, or percent contribution of protein to total metabolic expenditure. Providing a caloric intake of 40 kcal/kg/d was excessive, where 30 to 35 kcal/kg/d would meet metabolic demands. Pertinent clinical outcomes including length of stay, relapse rate, and survival were monitored, but no conclusions could be drawn in this study. The H-N formula was more effective in reducing loss of lean body mass without causing detrimental metabolic effects in BMT patients.

[Energy substrates in parenteral nutrition]

The most appropriate nutriment for total parenteral feeding (TPF) must be nutritionally efficient, safe and easy to use. Glucose is the most used carbohydrate as it has most of these qualities, as well as a high rate of metabolism by all tissues. It has not been clearly demonstrated that the administration of exogenous insulin with glucose improves nitrogen retention. Substitutes for glucose, such as fructose, maltose, galactose or polyols (xylitol, surbitol, glycerol) are not really superior to glucose itself. On the other hand, they have major side-effects. Therefore, they are not much used as energy substrates for TPF, at least not for long term TPF. Intravenous fat emulsions have taken an important place as a source of energy during TPF. Fat emulsions containing long chain triglycerides (LCT) supply essential fatty acids (EFA) (linolenic and linoleic acids), thus preventing EFA deficiency. The metabolism of fat emulsions is influenced by various factors: age, metabolic and nutritional status, the amount of glucose intake, insulin deficiency, sepsis, heparin therapy. Recently, medium chain triglycerides (MCT) have been proposed as an alternative energy source. The latter are cleared more rapidly from the blood, and are therefore less liable to be deposited in the liver and adipose tissue; they are also oxidized more quickly and more completely. MCT are safe to use at a rate of less than 0.12 g.kg-1.h-1 and with a MCT/LCT ratio less than 3 to 1. The simultaneous administration of glucose prevents an acceleration of ketogenesis. MCT/LCT emulsions are a safe and effective source of calories. It is important that those patients for whom such nutriment may be of particular interest should be identified. Fat emulsions associated with glucose seem to be more efficient in terms of nitrogen sparing effect than glucose alone. They also avoid the problems due to the infusion of large amounts of glucose (excessive carbon dioxide production, fatty infiltration of the liver), while there is no EFA deficiency. If the infusion of TPF nutriment must be continuous in intensive care patients, or during the postoperative period, cyclic nocturnal parenteral nutrition over a 12 or 16 hour period may be used in patients who are not in a catabolic state, or only mildly so. This is a safe and efficient method of nutritional support, which reduces the incidence rate of TPF-induced cholestasis.

Nutritional support in surgical practice: Part I

Critical evaluation of the therapeutic benefit gained from provision of nutritional support requires knowledge regarding the nutritional status of those to whom it was given. The apparent effect of giving parenteral nutrition or enteral nutrition depends not only on how much and how well it is given, but also on how depleted the recipient is. Thus, nutritional assessment requires close examination before proceeding to assess the efficacy and potential benefits of the remedial measures of parenteral nutrition or enteral nutrition. Although preoperative malnutrition is associated with a poor operative outcome, there appears to be no consensus as to whether perioperative nutritional support can reduce postoperative complications to the level occurring in well-nourished patients undergoing similar procedures. This is partly because reports evaluating the effect of perioperative nutritional support on postoperative outcome vary widely as to numbers of patients studied, primary diagnoses, and the duration and quality of perioperative nutritional support. In Part I, these issues are explored in patients who are undergoing operations for cancer, trauma, or burns. Enteral nutrition appears to be as effective as parenteral nutrition in improving operative outcome, as compared with ad libitum oral nutrition. Postoperative enteral nutrition and parenteral nutrition are equally effective in reducing postoperative complications.

A key to the literature of total parenteral nutrition: update 1987

This comprehensive bibliography is intended to enhance the education of the practitioner, student, and academician in the area of parenteral nutrition. This bibliography is not all-inclusive but serves as an update from the original published in 1983. Of particular note in this work is the addition of topics that reflect a growing interest in medical specialties with regard to patient nutritional status and support.