You admitted a 72 year old male to the ICU for septic shock from community acquired pneumonia. He required intubation and mechanical ventilation for failure to improve oxygenation with NIPPV and encephalopathy. He received broad spectrum antibiotics and a 30 cc/kg crystalloid bolus. His MAP was persistently in the 50s despite adequate fluid resuscitation and based on your exam he does not appear hypovolemic. Norepinephrine is started and despite adequate MAP he is oliguric. His only medical history is he was a previous smoker with COPD, HTN, HLD but normal renal function with a Cr of 0.8 two months prior. His Cr on admission is 2.2 and a foley is placed and his UA shows granular casts. He is not acidotic and his electrolytes are normal.
You are concerned this patient is heading towards renal replacement therapy. He is adequately fluid resuscitated and has a MAP above 65 on a vasopressor but is still not making urine and has signs of ATN on urinalysis. Renal replacement therapy is an invasive procedure and has associated risks. If a patient has a chance to have renal recovery with a more conservative approach then this should be considered. You wonder if there is a diagnostic test which can be used to assess the potential for renal recovery.