The development and clinical application of small intestinal perfusion studies in man

Russell, Robert Irvine (1976) The development and clinical application of small intestinal perfusion studies in man. PhD thesis, University of Glasgow.

Abstract

The subject of this thesis is the technique of small intestinal marker-perfusion applied to the measurement of jejunal absorption in man. The work describes studies performed in developing the technique and applying it to study factors involved in influencing intestinal absorption. Standard methods of investigating problems of maldigestion, malabsorption and various diarrhoeal states are generally indirect, and give little information on the direct absorption capacity of the small intestine. The development of long intestinal tubes opened up the possibility of directly studying the absorptive area of the small intestine. The initial use of non-absorbable, water-soluble markers in conjunction with long intestinal tubes was a major advance in the development of small intestinal intubation techniques. (Borgstrom, Dalqvist, Lundh et al, 1957 ). within a few years of this development early small intestinal perfusion studies were appearing. Since then, a number of different versions of the technique have appeared. There has, however, been no general agreement as to the best way to perform these studies. After an introductory section, the background to the development of the technique is described, and the necessary requirements discussed. Section II describes initial studies performed on the development of the perfusion system. The basic principles are defined, and a number of specific problems considered. These include the requirements of an adequate non-absorbable reference substance and the need for new markers, the choice of the perfusion tube system, and problems relating to the influence of flow rate and composition of the perfusion used in individual studies. The need for new and easily measured non-absorbable, water-soluble markers for perfusion studies led to a comparison of 51CrCl3 and 51Cr EDTA in the perfusion system by comparing each with phenolsulphonphthalein (PSP). The results show a good correlation for water absorption figures obtained using 51Cr EDTA with those using PSP, and a poor correlation between water absorption calculated using 51CrCl3 compared with those calculated using PSP. 51Cr EDTA thus appears to be a satisfactory non-absorbable water-soluble reference substance for intestinal perfusion studies. The composition of the perfusate was also investigated with particular reference to the relationship of glucose to sodium and water absorption. Using a triple-lumen tube perfusion system and perfusates consisting of isotonic-saline and glucose-saline with glucose concentrations ranging from 28 mM to 224 inM, it was found that with increasing concentrations of glucose up to 56mM, increasing absorption of water and sodium occurred. With high concentrations of glucose (224 mM) a marked reduction of water and sodium absorption. occurred, and net secretion of sodium was found in the jejunum. From these results a glucose concentration of 56 mM in glucose-saline solutions has been taken as being the best basic perfusate for subsequent jejunal perfusion studies. The effect of different perfusion flow rates on water and electrolyte absorption has also been studied. Infusion rates of 10 ml per minute, 15 ml/minute, 20 ml/minute and 25 ml/minute were investigated and no significant difference was found in the absorption of water and electrolytes at each of these rates. However, a trend towards a reduction of water and electrolyte absorption at 25 ml/minute was noted. Prom these results an infusion rate of 20 ml/minute was selected as the standard perfusion flow rate for the jejunal perfusion studies subsequently performed. Finally, in this section, the design of the intestinal tube system itself was studied. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: E M McGirr
• Keywords: Medicine
• Date of Award: 1976
• Depositing User: Enlighten Team
• Unique ID: glathesis:1976-72961
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 11 Jun 2019 11:06
• URI: https://theses.gla.ac.uk/id/eprint/72961