Ultrasound First Clinical Decision Support for Suspected Nephrolithiasis

CT scan is overused for patients who present to the ED with suspected nephrolithiasis (acute flank or abdominal pain). The investigators have developed a clinical decision support (CDS) tool to identify those patients in whom ultrasound is appropriate. The CDS tool is based on the Study of Ultrasonography vs. Computed Tomography for Suspected Nephrolithiasis in the Emergency Department.

The goal of this study is to assess the effectiveness of a clinical decision support (CDS) tool to improve advanced imaging for suspected nephrolithiasis in the ED. The investigators hypothesize those randomized to receiving the CDS tool will receive CT less often (and less radiation) compared to those receiving control. Also, the investigators hypothesize those randomized to receiving CDS will have a similar ED length of stay and rate of unexpected ED return as those receiving control.

Study design: Randomized trial of a CDS tool embedded in the electronic health record for patients with suspected nephrolithiasis. The study will be conducted at UCSF Department of Emergency Medicine.

Study subjects: The investigators will enroll adult patients who present to the UCSF ED who present with "suspected nephrolithiasis", which is defined as those with symptoms of nephrolithiasis for whom an ED provider orders a CT scan for suspected nephrolithiasis. Symptoms of nephrolithiasis include acute unilateral flank and/or abdominal pain, typically described as severe and colicky. The pain is accompanied by nausea, vomiting, and urinary symptoms, such as hematuria. The CT imaging studies emergency physicians typically order for suspected nephrolithiasis include CT scan without contrast; however a substantial minority of patients receive CT scan with contrast, and CT scan with and without contrast for acute flank pain, suspected nephrolithiasis.

Sampling, recruiting and retaining subjects: The investigators will enroll consecutive patients who present to the ED with the selection criteria. Those with suspected nephrolithiasis but have an exclusion criteria will be recorded and compared to those who were enrolled. Eligible patients will be randomized to either receiving CDS recommendations or no CDS recommendations. Subjects will not receive informed consent, and will not be contacted by staff.