The Continuous Withdrawal Method for the Quantitative Analysis of the Lower Oesophageal Sphincter (LES) in Humans

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Abstract
1. The continuous withdrawal method which has been used successfully in animal experiments for recording pressure profiles in the lower oesophageal sphincter, LES, was applied for the first time in human studies. A catheter with 4 side holes which served as a pressure transmitter, was continuously withdrawn from the stomach at a constant speed (6 mm/sec.) while constantly perfused (5 ml/min.). This procedure shows numerous advantages, particularly for quantitative analysis, when compared to both the stepwise pull‐through method and an open‐side catheter lying stationary in the sphincter. Thus the profiles obtained using the continuous withdrawal method are remarkable for their definition. Displacements, which can occur with a stationary catheter, are eliminated, and the pressure maximum can be definitely determined even if there is a shift in the area of maximum pressure. – 2. Pressure profiles of the LES taken with the withdrawal method in 20 conscious subjects usually showed a gradual, and then more rapid increase from aboral to oral, which after reaching a maximum value decreased steeply and changed into sub‐zero pressures. The maximum pressure taken from the pressure profiles of 20 subjects, being the mean value of all experiments, was 19 ± 7.3 mm Hg with a mean sphincter length of 3.4 ±0.6 cm (x̄±SD). The pressure profiles could be recorded at short intervals (0.5‐2 min.) without appreciable irritation of the sphincter. – 3. The continuous withdrawal method proved especially efficient, even after an increase of the sphincter tone induced by Pentagastrin (0.6 μg/kg I. V.). The mean results of the experiments in 6 test subjects showed that the maximum pressure in the LES increased from 13 ± 6.3 mm Hg to 44.2 ± 11 mm Hg 1 min. after the injection and the mean sphincter length increased from 3.9 ±1.2 cm to 5.3±1.4cm. These effects had subsided after 7–10 min. Pressure profiles obtained in this way, as well as supplementary measurements, indicated that Pentagastrin can cause a shift of the maximum pressure area in the oral direction.