GASTRIC EMPTYING DURING CONTINUOUS INTRAGASTRIC INFUSION.
Contributors: University of Calgary.
Published: 1989
Number of pages: 203
Subjects: Health Sciences, Nursing.; Health Sciences, Nutrition.
Description: Nasogastric tube feeding is a common method of nutrition support, but the pattern of gastric filling and emptying which occurs during constant infusion is unknown. Such information might permit manipulations of formula and infusion rate which would maximize nutrition support and minimize complications.

Nuclear medicine techniques were used to examine gastric retention during continuous nasogastric infusion of a hypertonic semi-elemental formula in eight healthy male volunteers. Technetium-99m sulfur colloid was mixed into the formula (Flexical HN$\circler$, 650 mOsm/kg, 1 kcal/ml) and infused at 110 ml/h for eight h. Anterior images of the abdomen were taken in 1-min frames every 15 min. Counts within the gastric region were corrected for decay and expressed as per cent of maximum counts. In three subjects, anterior and posterior images were taken and corrected for tissue attenuation of gamma emissions by calculating geometric mean values. The pattern of gastric retention of formula over time, as indicated by gastric retention of the radiomarker, demonstrated four phases: (1) an initial period of accumulation, (2) a plateau (maximum value reached at a mean of 2.25 h), (3) a period of declining gastric volume, and (4) establishment of steady state volume after 6 h of infusion. Mean peak (2.25 h) versus 8 h retention values were significantly different (p =.001). There was no difference in the pattern of gastric retention using the geometric mean values compared to either anterior or posterior data.

Gastric emptying was also examined in dogs, using duodenal marker perfusion. Validation of the method for use during continuous intragastric infusion was performed using a duodenal balloon method. A total of thirty-six experiments in three dogs were performed using either full or half strength Flexical HN and formula infusion rates of either 2 or 4 ml/kg/h (100% and 200%, respectively, of maintenance energy requirements). Mean gastric emptying rate increased during the initial 3-4 h, then approximated the formula infusion rate for the duration of the 12 h study period. Doubling the infusion rate at either formula concentration doubled the gastric formula volume achieved at 2 h. Doubling the formula concentration at a given rate of infusion had no effect on 2 h gastric formula retention. The duodenal balloon method was superior to marker perfusion in identifying the variation in gastric rate which occurred during continuous intragastric infusion, and in accurately measuring emptying rate during half strength formula infusion.
Notes: Source: Dissertation Abstracts International, Volume: 52-10, Section: B, page: 5194.

Thesis (PH.D.)--UNIVERSITY OF CALGARY (CANADA), 1989.

School code: 0026.