Which assessment finding does the nurse associate with the patient's AKI, postrenal type?

In the context of acute kidney injury (AKI), particularly in the postrenal category, the association with a feeling of urgency is significant because this condition often arises from obstructions in the urinary tract that affect the flow of urine. When such an obstruction occurs—whether due to kidney stones, tumors, or other causes—it can lead to increased pressure in the urinary system, causing the bladder to sense this pressure as an urgency to void. This feeling results from the bladder's normal function reacting to changes in pressure and volume, which can be quite distinct when there is an obstruction present.

Other findings such as elevated BUN and creatinine are more commonly linked to the physiological processes that occur during renal impairment, but they do not specifically indicate postrenal causes. Weight gain can occur due to fluid retention associated with kidney dysfunction, but it is more general and can occur in various types of renal dysfunction rather than being specific to postrenal causes. Thus, the feeling of urgency is a key symptom that underscores the postrenal nature of the AKI, indicating that the obstruction is affecting the normal excretion of urine.