Does urine output matter in a dialysis patient?

[Capp]

I have a stupid question for nurses who have more experience with dialysis than me. Obviously a patient on dialysis is expected to have lower urine output than normal, but is there a point when you are supposed to be concerned about low urine output in a dialysis patient? Or do you just not worry about it?

[KatieMI, BSN, MSN, RN]

Rule of thumb:

1) find patient's baseline

2) everything significantly off that baseline (50% either way) is concerning

Here is why:

Chronic renal failure can be, basically, glomerular (glomeruli are dead) and tubular (glomeruli are alive but tubular apparatus is dead). If there are no glomeruli, there can be no FILTRATION, patient makes no urine. If glomeruli are partially alive but tubuli are dead, filtration can continue but there is no REABSORPTION. In the latter case, patients can make quite a bit of urine and can become dehydrated. Their urinary output needs to be closely recorded for this reason.

In cases of ACUTE renal failure requiring dialysis the most common point of injury are tubuli (acute tubular necrosis, ATN). The recovery from anuric/olyguric to polyuric stage can take weeks and patient might need dialysis at some point. The recovery starts from patient starting to make urine, sometimes in large amount. This is a dangerous moment, as reabsorption of electrolytes and pH regulation recover much later, and dialysis settings must be adjusted once the patient starts to make urine.

Last but not least, patients who make even small amount of urine can develop postrenal obstruction (stones) and UTIs. They need to be monitored just like patients without renal failure for symptoms of these complications.