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Chapter 13 (page 51)
While investigating mucosal fold movements in the distal 3.0 to 4.0 cm of the stomach,
i.e. within the confines of the anatomical pyloric sphincteric cylinder, as well as in the
duodenum, intraluminal pressure studies were combined with radiological imaging
procedures in 11 normal subjects (Keet et al l978) (Chap. 15). These investigations may,
at the same time, be utilized to determine the relationship between intraluminal pressures
and radiologically demonstrable, physiological movements of the circumference of the
barium column in these regions. (In this context "movements" do not imply propulsion
or retropulsion of contents).
All subjects taking part were informed, volunteer, adult, male ambulatory outpatients
who had been referred for an upper gastro-intestinal radiographic study because of vague
abdominal symptoms. None had had any significant clinical signs at the preliminary
clinical examination. Only patients in whom no organic lesion could be demonstrated in
the oesophagus, stomach and duodenum at the radiological examination were admitted to
the study; it was cleared by the Ethical Committee.
Pressure recordings were obtained by means of an air-filled system and a miniature
balloon, placed on the immediate oral side of the pyloric aperture (i.e. in the lumen of the
pyloric sphincteric cylinder) in 5 subjects, and in the second or third parts of the
duodenum in 6 other subjects.
A pressure sensitive system usually used for cardiovascular physiology, with some
modifications, was employed. It consisted of a monitor (Statham SP1400) (Statham
Instruments Inc., Los Angeles), a miniature transducer (Statham P37B), a recorder
(Statham SP2006) and a catheter, 125 cm in length, with an outside diameter of 2.0mm.
A miniature balloon 38 mm in length and 8.0 mm in diameter, covered the 6 endholes of
the catheter. The volume of air introduced into the balloon to achieve zero pressure was
0.8 ml. After an overnight fast the balloon was manipulated into position under TV
screening, with the subject in the erect position. Four mouthfulls of a fluid barium
suspension were swallowed to delineate the lumen and for purposes of localization. In
the absence of visible motor activity the diameter of the pyloric sphincteric cylinder was
approximately eight times the diameter of the balloon (visible because of its air content),
and the diameter of the duodenum three times that of the balloon. Artifacts such as
subject movement, coughing and pressure increases produced during compression
procedures were identified and excluded. Pressure increases were correlated with
motility of the barium column as viewed radiographically, and vice versa.
In the pyloric sphincteric cylinder the base line of the curve represented intraluminal
pressure while the cylinder was distended, in the absence of radiologically visible motor
activity (Fig. 15.1). The following two distinct waves of pressure increase were noted
- Irregularly occurring, nonrhythmic contractions, causing intraluminal pressure
increases varying from 9.0 to 34 mm Hg (the majority being in the range of 12 to
25 mm Hg). These waves lasted for 5 to 21 seconds (the majority being in the 6
to 10 second range) (Fig. 15.1), occurred repeatedly in all subjects and conform to
Type II contractions (Code and Carlson l968; Shepard l97l).
- In two of the subjects compound waves, consisting of a rise in base line pressure
of 3.0 to 5.0mm Hg and lasting for 10 to 40 seconds, on which were
superimposed waves of shorter duration (3 to 5 seconds) and higher amplitude (up
to 12 mm Hg), were recorded; these conform to Type III waves (Shepard l97l).
Simultaneous radiological TV monitoring showed that both waves of pressure
increase were associated with a concentric narrowing of the barium column
characteristically occurring in this situation (see below). The higher the
amplitude of the pressure wave, the greater the luminal narrowing appeared to be
It was concluded that the narrowing of the barium column was due to active contraction
of the walls.
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