Stopping Enteral Feeding for Arbitrary Gastric Residual Volume May Not Be Physiologically Sound: Results of a Computer Simulation Model

Abstract

Background: 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. Methods: 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. Results: (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. Conclusions: 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. (journal of Parenteral and Enteral Nutrition 21:286-289, 1997)

Get full access to this article

View all access options for this article.

References

McClave SA , Snider HL , Lowen CC , et al: Use of residual volume as a marker for enteral feeding intolerance: Prospective blinded comparison with physical examination and radiographic findings. JPEN 16:99-105, 1992

Hunt JN : The site of receptors slowing gastric emptying in response to starch in test meals. J Physiol (Lond) 154:270-276, 1960

Lin HC , Doty JE , Reedy TJ , et al: Inhibition of gastric emptying by glucose depends on length of intestine exposed to nutrient. AmJ Physiol 256:G404-411, 1989

Lin HC : Disorders of gastric motility and emptying. IN Principles and Practice of Gastroenterology and Hepatology, 2nd ed, Gitnick G (ed). Appleton & Lange, Norwalk, CT, 1994, pp 99-108

Lin HC , Zhao XT , WangLJ: Jejunal brake: Inhibition of intestinal transit by fat in the proximal small intestine. Dig Dis Sci 41:326-329, 1996

Spiller RC , Trotman IF , Higgins BE , et al: The ileal brake-inhibition of jejunal motility after ileal fat perfusion in man. Gut 25:365-374, 1984

Ganong WF : Gastrointestinal motility and secretion. IN Review of Medical Physiology , 8th ed. Lange Medical Publications , Los Altos, CA, 1977, pp 360-383

Kohn CL , Keithley JK : Enteral nutrition: Potential complications and patient monitoring . Nurs Clin N Am 24:339-353, 1989

Anonymous : American Gastroenterological Association technical review on tube feeding for enteral nutrition. Gastroenterology 108:1282-1301, 1995

10.

Mullan H. , Roubenoff RA , Roubenoff R. : Risk of pulmonary aspiration among patients receiving enteral nutrition support . JPEN 16:160-164, 1992

11.

Coben RM Weintraub A. , DiMarino AJ Jr. et al: Gastroesophageal reflux during gastrostomy feeding. Gastroenterology 106:13-18. 1994

12.

Bowling TE , Silk DBA : Enteral feeding-problems and solutions. Eur J Clin Nutr 48:379-385. 1994

13.

Spiro HM : Clinical Gastroenterology. 3rd ed. Macmillan Publishing Company, New York . 1983

14.

Davenport H. : Secretion of bile. IN Physiology of the Digestive Tract. 5th ed. Davenport H (ed). Yearbook Medical Publishers, Chicago, 1982. pp 54-56

15.

Livingston EH Passaro EP Jr: Postoperative ileus. Dig Dis Sci 35:121-132, 1990