During open irrigation of a client's indwelling urinary catheter, which action should the nurse take?

The correct action during open irrigation of a client's indwelling urinary catheter involves managing the client's urine output accurately in relation to the irrigation process. When a nurse performs irrigation, it is essential to keep track of the total volume of fluid introduced, as it can impact the assessment of the patient's urinary output.

Subtracting the amount of irrigation fluid used from the total urine output helps provide a clearer picture of the client's actual kidney function and fluid balance. This is necessary because the fluid instilled does not contribute to urine formation; therefore, it should not be counted as part of the urine output measured. This practice allows for a more accurate assessment of a client’s renal function and fluid status.

Considering the other options, placing the client in a side-lying position may not be necessary and does not directly relate to the effectiveness of the irrigation process. Instilling 15 mL of irrigation fluid with each flush might not align with best practices; the recommended volume can vary based on clinical guidelines and the patient's specific needs. Performing the irrigation using a 20-mL syringe may also not be universally appropriate, as the method and equipment used can depend on the facility’s protocol or the particular circumstances surrounding the patient’s care.