Enteral Feeding Practices Research Articles

From TPN to breast feeding--feeding the premature infant--2000: Part I. Parenteral nutrition.

Advancements in medical technology have allowed for the survival of smaller, more premature infants, during the past several years. Infants as immature as 23 weeks gestational age and as small as 500 g, or even less, are now common sights in Neonatal Intensive Care Units throughout the United States. These infants present a unique challenge to neonatologists and registered dietitians, who must provide them with the nutrients needed for normal growth and development. With mounting evidence of a direct link between early nutrition and later outcome, the need for a better understanding of fetal and neonatal nutrition is critical. From admission to discharge, most infants will transition from a dependence on parenteral feeding, to a dependence on tube feeding, and finally, the ability to orally feed. In the early days of postnatal life, decisions must be made about when to initiate TPN, what type of intravenous access will be required, and to what extent and at what rate parenteral nutrients should be advanced. Similar decisions are made about the introduction and advancement of enteral nutrition. The following is a review of the available literature on the parenteral feeding of premature infants, with an emphasis on how our practice in the year 2000 was evolved over time. A similar review of enteral feeding practices will be presented in a future installment.

New options for pumps and tubes: progress in enteral feeding techniques and devices.

In the past, blenderized tube feeds prepared in the hospital kitchen were delivered by bolus or gravity at intervals of 4-6 h. These methods lack consistent steady flow and many times are not a safe mode of delivery for those at risk of vomiting and aspiration, and cause more patient discomfort than nutritional benefit. More recently, enteral feeding administration techniques and devices have been developed for the delivery of commercially prepared enteral formulas designed for specific disease states. These technological advances have improved enteral feeding practices.

Stopping enteral feeding for arbitrary gastric residual volume may not be physiologically sound: results of a computer simulation model.

During tube feeding, it is a common practice to check gastric residual volume frequently for indications of pathologic impairment of gastric emptying. The volume threshold standards for holding feedings are applied nonselectively, disregarding slowing of gastric emptying by nutrient-triggered intestinogastric inhibitory feedback. We developed a computer simulation model considering this feedback to test the hypothesis that gastric residual volume increases with slower gastric emptying and faster formula delivery but reaches a plateau volume (equilibrium between input and output) at volumes commonly seen in the postprandial stomach. A computer simulation model using Microsoft Excel 4.0 calculated the cumulative gastric residual volume over time when the input volume into the stomach is 125 mL/h (endogenous secretions)+ 0 to 125 mL/h (formula delivery rate) and the output volume out of the stomach is equal to gastric emptying rates that varied between 0% and 50%/h. The model simulated nasogastric feeding with nine different rates of gastric emptying and six different rates of formula delivery. Measurements consisted of the cumulative gastric residual volume at the end of each hour for a minimum of 48 hours. (1) Gastric residual volumes 1.5 to 6 times the commonly applied "stop feeding" threshold volume of 150 mL are encountered at gastric emptying rates of 20% to 50%/h; (2) gastric residual volume stabilizes to a plateau of 225 to 900 mL between 3 and 13 hours after start of formula delivery at these rates; and (3) at 0% gastric emptying, gastric residual volume does not reach a plateau. At gastric emptying rates expected with nutrient-triggered inhibitory feedback and at formula delivery rates common in nutrition support, gastric residual volume reaches a plateau rapidly and at volumes commonly encountered in normal postprandial stomachs. On the basis of the results of this model, the current practice of stopping enteral feeding when gastric residual volume exceeds an arbitrarily selected volume threshold may not be physiologically sound. Clinical studies are needed to verify this model.

Enteral nutrition practices: Similarities and differences between dietitians and physicians in Connecticut

There has been little evaluation of attitudes, beliefs, and practices of health professionals involved in the provision of enteral nutrition support. A study was undertaken to define and describe enteral feeding practices of registered dietitians (R.D.s) and physicians (M.D.s) in Connecticut. Survey questionnaires were returned by 74.5% of R.D.s and 53.3% of M.D.s. Data were analyzed for 195 respondents. Overall, there were more similarities than differences between R.D.s and M.D.s. Malnutrition was the most frequent indication for tube feedings. Dietitians and physicians selected formulas on the basis of nutrient needs of the patients, but R.D.s gave significantly more weight to formula design and nutrient composition than did M.D.s. Lactose-free low-residue, high-calorie high-nitrogen, and elemental diets were considered to be the most desirable products to include in a hospital formulary. Dietitians more frequently monitored nutrition-related parameters, whereas M.D.s followed metabolic parameters of patients on tube feeding. Physicians relied on R.D.s to recommend formulas and to provide them with enteral nutrition information. The results from this study may be useful in planning nutrition education programs, evaluating standards for enteral nutrition practice, and improving utilization of enteral nutrition therapy.