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 nephrolithaisis.

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.

Intervention: The intervention is the CDS tool, which consists of 4 components:

1. Four questions which assess the appropriateness of ultrasound for this patient

2. A link to the evidence

3. Buttons to remove CT scan and order ultrasound

4. If the CT scan order is kept, reasons why ultrasonography is not appropriate

The CDS tool will be placed or integrated into EPIC, at the point of order entry. The tool
will be triggered by an order for CT to identify or rule out kidney stone.

Co-primary outcomes: Proportion of study arm who receive CT, and radiation dose. Proportion
of study arm who receive CT is defined as #CT scans ordered/#patients in study arm. Radiation
dose will be reported as median radiation dose in mSv. The secondary outcomes will include
proportion of patients with an unscheduled return due to missed diagnosis, cost, ED length of
stay.

Inclusion Criteria:

- Adult patients who present to the ED with flank or abdominal pain for whom ED provider
orders a CT scan for suspected nephrolithiasis

Exclusion Criteria:

- Previous enrollment into the study