Final answer:
The correct instruction for a patient scheduled for a double-contrast barium enema is to have a low residual diet 1-2 days before the procedure, eat a light meal the night before, and not to decrease fluid intake after the procedure.
Step-by-step explanation:
When preparing for a lower gastrointestinal study using a double-contrast barium enema, the correct instruction to include in the client's teaching is to have a low residual diet 1-2 days before the procedure. This is because it is essential to have the bowels clear so that accurate imaging can be obtained.
A low residual diet helps to reduce the volume and frequency of stool and minimizes the residue in the digestive tract. It's also recommended that patients eat a light meal the night before the procedure and avoid foods that are high in fiber, as these can leave residue that may interfere with the quality of the X-ray images. Increasing fluid intake before the procedure may also be advised to help clear any residual content from the gastrointestinal tract. After the procedure, normal diet and fluid intake can typically be resumed unless otherwise directed by the physician. It should be noted that the procedure will not take 6 hours and decreasing fluid intake after the procedure is not recommended.