(4) At a given signal from the radiologist, the specialist inserts the rectal tip
into the patient's anus. Just before making the insertion, a small amount of contrast
medium should be allowed to flow through the tube in order to squeeze out the residual
air. The patient is rolled onto his side on the table with his knees flexed. The rectal tip
is inserted into the anus with a steady, gradual pressure, exerted anteriorly. When the
tip is passed beyond the anus, it should be directed forward at an angle in line with the
umbilicus. Due to the extreme sensitivity of the rectal region, care must be exercised in
making the insertion. In case a retention catheter is used, caution must be exercised
not to distend the inflated bulb excessively. Whenever possible, allow the patient to
insert the tip, himself. Be sure to provide appropriate instructions.
(5) Upon a signal from the radiologist, the specialist initiates the flow of the
contrast mixture and fluoroscopic observation is made. The radiologist will signal the
specialist when to interrupt and when to resume the flow of the contrast medium. It is
imperative that the specialist respond instantly to these signals. Spot filming may also
be done during this phase of the examination. As the patient is maneuvered for
changes in position, the specialist should take care to see that the enema bag tubing
does not become kinked or accidentally withdrawn. If the tube should become clogged,
the obstruction can usually be moved by stripping or "milking" the tube in the direction of
flow. If the radiologist desires the filling of the bowel to proceed at a slow rate, the
specialist can control the rate of filling by lowering the enema bag or by pinching the
tubing between the fingers. Upon completion of "filling" and fluoroscopy, the patient is
cautioned to retain the contrast medium until radiography is accomplished. It may be
advisable to leave the rectal tip in place until all radiographs are done. This sometimes
prevents the patient from prematurely expelling the contrast medium.
e. Radiographic Examination.
(1) Regardless of the type of setup (single-unit; single-unit, supplemented;
or double-unit), it is usually best to do radiography of the barium-filled colon by having
the patient remain on the same x-ray table on which fluoroscopy was performed. This
lessens the possibility of accidental evacuation. The required radiographs are made in
accordance with established routine or as directed by the radiologist.
(2) For the single-contrast barium enema, a PA projection of the barium-
filled colon (figures 2-16 and 2-17) is obtained. Details are as follows:
Film. 14 x 17-inch, lengthwise.
Position. Patient prone, level of iliac crests to the center of the film.