An Assessment of the Value of Measuring Uncollected Gastric Secretion During Routine Secretion Studies in Man

Abstract

A simple 'wash-out ' collection technique employing phenol red as a marker has been used during routine gastric secretion studies and its value has been assessed. Studies repeated on a single individual showed good reproducibility. When measured this way loss was not affected greatly by the volume secreted.With this technique the repeatability of pentagastrin tests has been assessed at intervals of 6 weeks. This demonstrated that both acid and pepsin outputs could vary considerably, with a mean variation in acid of over 26 per cent.The effects of histamine, pentagastrin, and insulin upon loss have been studied.Loss has been found to vary considerably from one study to another and from one patient to another and may on occasions be considerable, particularly after previous surgery.These findings suggest that a method of measuring loss should be adopted by any centre which wishes to use secretion studies to analyse the effects of treatment.THE value of secretion studies in clinical practice depends upon the accuracy with which they are performed. One possible source of inaccuracy is the failure to collect all the secretion produced, giving a falsely low calculated secretion. Surprisingly few workers have attempted to measure such losses so that the value of estimating the amount of secretion escaping collection has not been assessed fully.The present study was designed to establish a simple method of collection. Sophisticated techniques (such as the use of a radioactive marker) have been avoided and the method described relies upon changes in the concentration of phenol red (a nonabsorbable marker) between the time of instillation and withdrawal from the stomach. MATERIALS AND METHODSTechnique.-Prior to a test all medications were withheld for 24 hours and the subject was fasted for 12 hours.A double-lumen tube of special construction was used (Fig. I). One lumen ended 15 cm. proximal to the other and had two holes drilled near its end to produce a fine spray when phenol red was infused through it. Infusion was controlled by a peristaltic pump (Watson-Marlowe) at a rate between 10 and 15 ml. per minute. Phenol red was made up before a test by adding 20 ml. of stock solution (1.5 g. per litre) to 2 litres of distilled water. The second lumen FIG. I.-Diagrammatic representation of the collection technique.

Mucus degradation by pepsin: comparison of mucolytic activity of human pepsin 1 and pepsin 3: implications in peptic ulceration.

“…3). Pentagastrin stimulated gastric juice from non-symptomatic volunteers (age [18][19][20], however, did not show such increased mucolytic activity above pH 4. Direct comparison of the results from the DU patients and non-symptomatic volunteers is not possible as they were not age matched.…”

“…, d l l ________________________ .Over 30 min incubation there was a substantially 20 Frction N 60 7 greater drop in viscosity of the gastric mucus when vo vt incubated with human purified human pepsin 1 Gelfiltration on Sepharose 2B ofpurified pig compared with purified pepsin 3 (human or pig) for ic mucus glycoprotein (0). The glycoprotein before the whole pH range 1c(5.…”

Endogenous prostaglandins in peptic ulcer disease.

“…After an overnight fast and the withholding of all medications for 24 hours, a double-lumen nasogastric tube was passed into the stomach and its satisfactory position confirmed by the recovery of a known amount of injected fluid. A 'wash-out' technique employing phenol red as marker was used to estimate the amount of secretion escaping collection (Venables, 1972). Resting gastric secretion was aspirated and discarded.…”

The relationship of anaemia to gastric secretion more than 15 years after vagotomy and gastro-enterostomy

“…was assessed in all the patients either by separate tests or by a combined pentagastrin/insulin test (Venables, 1972). Gastric secretion was collected by a 'washout' technique in all but one patient ; this technique allowed an estimate of uncollected secretion to be made.…”