When calculating total urine output from a continuous bladder irrigation system, how is true urine output determined?

True urine output in the context of a continuous bladder irrigation system is determined by subtracting the volume of irrigating solution used from the total volume of fluid that drains out. This calculation is essential because the irrigation solution is continuously infused into the bladder to keep it clear of clots and debris, and thus, the total outflow includes both urine and the irrigant fluid.

By subtracting the irrigant volume from the total outflow, healthcare providers can accurately assess the patient's actual urine output. Accurate measurement of urine output is critical for assessing kidney function and fluid balance, especially in patients who have undergone surgical procedures related to the urinary tract or those who are experiencing urinary retention.

Other options may lead to incorrect conclusions about the patient's fluid status. Measuring only the total outflow would not account for the volume of irrigant, leading to an inflated sense of urine output. Adding the irrigant to the output would also misrepresent the true urine output, potentially causing confusion regarding the patient's renal function. Measuring output every hour does not address how to correctly calculate the actual urine produced. Therefore, subtracting the irrigant volume is the appropriate method for accurate assessment.