Final answer:
To treat constipation, a patient should try to retain an oil-retention enema for at least 15 to 20 minutes, so the oil can soften the stool and lubricate the rectum.
Step-by-step explanation:
The student is asking about the appropriate duration for retaining an oil-retention enema when treating constipation. Typically, for an oil-retention enema to be effective, it is generally recommended that the patient attempts to retain the oil for at least 15 to 20 minutes. Retaining the enema allows the oil to soften the stool and lubricate the rectum, making it easier to pass the stool. However, it's important to follow specific instructions provided by a healthcare professional, as duration might vary based on individual circumstances and the type of oil used.