Utilization of Renal Ultrasound for Predicting Obstructive Uropathy in ICU Patients With Acute Kidney Injury.

SESSION TITLE: Non Pulmonary Critical Care PostersSESSION TYPE: Original Investigation PosterPRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PMPURPOSE: Renal ultrasound (rUS) is the standard of care for patients presenting to the ICU with Acute Kidney injury (AKI) despite previous studies suggesting that only a small subset of patients with AKI have obstructive uropathy. Thus, we sought to (1) assess which clinical findings may raise or lower the pre-test probability of finding obstructive uropathy on rUS, and (2) examine how often the finding of obstructive uropathy led to changes in management.METHODS: We retrospectively analyzed 231 patients admitted with AKI to an adult ICU at a community teaching hospital. The electronic medical records were abstracted on all patients who underwent rUS for AKI evaluation while in the ICU. Each admission was evaluated for factors known to predispose to AKI by reviewing the rUS results, clinical documentation and the medication-administration record. Risk factors of interest included hypotension, exposure to nephrotoxic medications in the month before admission, high-risk diagnoses for pre-renal or post-renal AKI, angiography procedures and contrast administration.RESULTS: From the 231 patients analyzed, 13 patients (5.9%) had findings concerning for obstructive uropathy on rUS. Only 3 of these patients underwent placement of nephrostomy tube or ureteral stent. Our results were statistically insignificant when analyzing the individual risk factors for predicting obstructive uropathy except for patients who had a predisposing condition that placed them at a higher risk for post-renal AKI (LR 3.479, p value 0.033). However, when these individual risk factors are combined, patients who were at a higher risk for post-renal AKI plus had evidence of hypovolemia or shock have an increased predicted risk of obstructive uropathy (LR of 0.598 and 0.382 respectively, p value <0.05). Those patients at higher risk of AIN with pre-renal AKI or shock have a lower predictve risk of obstructive uropathy (LR of 0.014 and 0.013 respectively, p value <0.05).CONCLUSIONS: Our results corroborate the findings of previous studies and suggest that rUS has a low yield for ICU patients with AKI. Finally, we identified certain factors from the history, physical exam, and routine tests that may assist with determining the pre-test probability for obstructive uropathy. The presence of these characteristics may influence the decision to order rUS in ICU patients with AKI.CLINICAL IMPLICATIONS: Renal ultrasounds should be judiciously utilized in evaluation of AKI and cost-effective medicine should be practiced without compromising patient safety.DISCLOSURE: The following authors have nothing to disclose: Syed Amin, Reejis Stephen, David Morris, David KaufmanNo Product/Research Disclosure Information.