We use the Parkland Formula to determine how much fluid the patient should get and their UO target is 0.3-0.5 ml/kg of their dry weight and we try to stick to that range. We don't want to give too much fluid and create a whole new set of problems.
We do use SVV to get an idea of the the patient's fluid status but it's just another tool. And if after 12 hours their INR is greater than 1.5 we'll hang FFP with the albumin and LR ("Half quarter/quarter).
Some factors we consider when a resuscitation isn't going well are CVP, bladder pressures if they're circumferential to rule out abdominal compartment syndrome, medical history, medication history (are they lasix dependent?), did we calculate their TBSA% correctly, base deficit to see how dry they are, and some others I can't think of right now.
If they're UO is incredibly high we'll also want to know their blood alcohol level, blood sugar, medical history, etc. If they're really drunk or an out of control diabetic, we'll know to not back off on the fluids so we don't get behind.
But urine output really is the main factor determining the course of a resuscitation.
Also! Our doctors never bolus during a resuscitation. The idea being its simply a band-aid and you haven't addressed the underlying problem of capillary permeability. Their UO will drop off again in a couple hours guaranteed. If you bolus, you should increase their rate after. Some residents hate this and don't appreciate nurses telling them to call the staff to make sure they're aware of an impending bolus crime, but in the end it works out.
Hope that helps.