Point of Care Ultrasound for Suspected Small Bowel Obstruction in the Emergency Department
Point of Care Ultrasound for Suspected Small Bowel Obstruction in the Emergency Department
The primary purpose of this study is to determine the accuracy of ultrasound in diagnosing
 small bowel obstruction in emergency department patients, as compared to the criterion
 standards of computed tomography, operative reports, or discharge diagnosis.

 The secondary purposes of the study include evaluation of the effect of ultrasound for small
 bowel obstruction on the patient length of stay in the emergency department and the
 diagnostic utility of specific ultrasound findings in the diagnosis of small bowel
 obstruction. The study will also examine the inter-rater agreement between point-of-care
 sonographers' interpretation and blinded reviewers' interpretation of the ultrasound images.
Background:

 An estimated 15% of emergency department (ED) patients admitted to a surgical unit with
 abdominal pain are ultimately diagnosed with small bowel obstruction (SBO) (1). The work up
 of patients with possible SBO is directed by the patient history, physical examination and
 pre-test probability. Relatively insensitive abdominal x-rays (AXR) are commonly ordered as a
 screening test, but computed tomography (CT) imaging is often necessary to confirm or exclude
 the diagnosis of SBO. This diagnostic process is time consuming, costly and exposes the
 patient to ionizing radiation.

 Interest in point-of-care (POC) ultrasonography (US) for the evaluation of suspected SBO has
 increased in recent years. A growing body of literature suggests US is more sensitive and
 specific compared to AXR in the diagnosis of SBO (1-3). US also confers the benefits of less
 radiation exposure and more rapid decision-making. CT is generally considered the diagnostic
 criterion standard for SBO, but effective use of POC US may reduce the need for CT imaging
 and expedite the care of patients with suspected SBO.

 Currently, there are five emergency physicians (EP) on staff in the York Hospital ED who are
 fellowship trained in POC US. These physicians are fully credentialed and are already
 performing ED based evaluations for small bowel obstruction. We intend to evaluate the
 performance of EP-performed POC US in the diagnosis of SBO in ED patients. This study would
 primarily investigate the accuracy of ultrasound as compared to the criterion standard of
 abdominal CT results, intraoperative diagnosis, or discharge diagnosis.

 Study design:

 This will be a prospective, observational study of adult ED patients suspected of having a
 SBO. ED nurses, residents, and attendings will perform the initial screening for potential
 enrollees. Once consented and enrolled, a study sonographer will interview and examine the
 patient, preferably before labs and AXR results. The ultrasound must be completed and
 adequate images obtained before advanced imaging modalities are completed. Ultrasound of all
 four abdominal quadrants will be performed using the "mowing the lawn" technique described
 previously in the literature (4).

 The ultrasounds will be performed by all five of the US fellowship-trained EPs on staff, as
 well as two current emergency ultrasound fellows and three emergency medicine residents. All
 will participate in the identification, consent, and enrollment of patients in the study.

 Trainees will undergo an hour-long educational session on POC US for SBO involving both
 lectures and hands on training. Methods for proper consent and data collection will be
 included. Blinded review of each ultrasound is already planned as a component of the study
 design and treatment decisions will not be made based on trainees ultrasounds unless
 supervised by a credentialed faculty member. The five faculty EP sonographers are already
 fully credentialed in POC ultrasound and familiar with the technique for SBO. No additional
 ultrasound training will be required for these participants.

 A "Bedside" standardized data collection form will be used at the bedside to record
 ultrasound findings and clinical information. The sonographer will designate the ultrasound
 as "positive for small bowel obstruction," "negative for small bowel obstruction," or
 "indeterminate" based on the exam and ultrasound findings.

 A second sonographer, blinded to all clinical information and the primary sonographer's
 ultrasound interpretation, will review the de-identified ultrasound images remotely. This
 over-reading sonographer will record his interpretation and secondary findings on a "Blinded
 Reviewer" standardized data collection sheet. Only fully credentialed, fellowship-trained EPs
 will serve as secondary, blinded reviewers. Current fellows and residents involved in the
 study will not review ultrasound images in this capacity.

 CT imaging, intraoperative reports, and discharge diagnosis will be utilized to determine
 final outcome of patient's clinical course. At this time, a third "Follow Up" standardized
 data collection sheet will be used to record patient outcomes and demographic information.

 In general, CT reports will be used as the criterion standard to which POC US findings will
 be compared and by which sensitivity/specificity will be calculated. If no CT is obtained,
 then operative report(s) will serve as the criterion standard. If the patient does not
 receive CT imaging or undergo surgical intervention, then the discharge diagnosis will serve
 as the criterion standard.

 Study population and recruitment methods:

 The study population will include adult patients presenting to the emergency department with
 abdominal pain and a clinical suspicion of SBO. A treating attending physician or resident
 will evaluate the patient. If there is a concern for SBO, the treating physician will contact
 one of the ultrasound credentialed EP sonographers to perform a POC US to evaluate for
 possible SBO. This process is the current practice standard in the ED.

 At this point, the EP sonographer will approach the patient regarding the study. If the
 patient agrees to participate, the EP sonographer will obtain informed consent. Of note, the
 patient's treatment is unchanged, regardless of whether or not he/she consents to
 participation in the study. The POC US will be obtained in either case, as this is standard
 clinical practice in the ED. Agreeing to participate will simply allow the study team to
 collect data and review their chart upon discharge from the hospital. The study sonographer
 will obtain consent.

 Data to be collected:

 The following data will be recorded:

 -  Patients initials

 -  Patient Medical Record Number (MRN)/Financial Number (FIN)

 -  Age

 -  Sex

 -  Height

 -  Weight

 -  Chief complaint

 -  Presence/location of abdominal pain

 -  Symptom duration

 -  Associated symptoms (i.e. nausea/vomiting, diarrhea, etc.)

 -  Visualization of the small bowel?

 -  Maximum inner diameter of the small bowel?

 -  Presence of "to-and-fro" peristalsis?

 -  Edema of the wall of the small bowel?

 -  Presence of free fluid surrounding the small bowel?

 -  Presence of sonographic transition point?

 -  Diagnostic impression of the sonographer

 -  Diagnostic impression of the blinded reviewer

 -  XR findings

 -  CT diagnosis

 -  Operative report classification

 -  Time of patient placement in ED bed

 -  Time of consultation or ED discharge

 -  Discharge diagnosis

 Data analysis:

 For the primary outcome, data will be used to calculate the sensitivity and specificity of
 POC US for the diagnosis of SBO compared to the criterion standard of CT or operative report.

 For secondary outcomes, likelihood ratios for specific ultrasound findings will be
 determined. Inter-rater agreement between the bedside sonographer and the blinded reviewer
 will be calculated using Cohen's kappa coefficient. Continuous, time-to-disposition data will
 be compared utilizing a two-tailed t-test.

 Statistical analysis will be performed using SPSS software (IBM, Armonk, NY).

 Risks and risk management:

 There are minimal risks to patients participating in this study since ultrasound is
 non-invasive and known to be safe. There is a slight risk of the participants' privacy or
 confidentiality being breached. Standard precautions will be taken to ensure privacy and
 confidentiality is maintained during the study.

 Benefits:

 Patients whose ultrasound is highly suspicious for small bowel obstruction may be referred
 directly to surgery without further imaging being performed. In these instances study
 patients would benefit from reduced radiation exposure and faster referral for appropriate
 surgical care. The results of this study may be used to improve future patient care.

 Compensation / incentives and research-related costs:

 No compensation will be given to the participants. There will be no research-related costs.

 Alternative procedures:

 Patients who refuse to participate in the study will not have the quality of their treatment
 affected in any way.

 Research materials, records, and confidentiality:

 Research records will be stored in locked offices, filing cabinets, and computers using
 password-protected encryption.

 Subject informed consent:

 We will seek documented informed consent and Heath Insurance Portability and Accountability
 Act (HIPAA). ED patients meeting all of the inclusion and exclusion criteria will be asked if
 they would like to participate in the study by a research sonographer at the time of the
 ultrasound.

 If the patient agrees to participate, the informed consent document will be given to them for
 their review. If patient declines to participate they will continue their treatment course in
 the Emergency Department.

 References of relevant literature:

 1. Taylor, Mark R. and Nadim Lalani. Adult Small Bowel Obstruction. Academic Emergency
 Medicine. 2013; 20:528-544.

 2. Jang, Timothy B, et al. Bedside Ultrasonography for the Detection of Small Bowel
 Obstruction in the Emergency Department. Journal of Emergency Medicine. 2011;28:676-678.

 3. Suri, S, et al. Comparative evaluation of plain films, ultrasound, and CT in the
 diagnosis of intestinal obstruction. Acta Radiologica. 40(1999): 422-428.

 4. Mallin, Mike and Matthew Dawson. Introduction to Bedside Ultrasound: Volume 2. Emergency
 Ultrasound Solutions. 20 May 2013.

 5. Ko, Tae, et al. Small Bowel Obstruction: Sonographic Evaluation. Radiology.
 1993;188:649-653.

 6. Ogata, Masaaki, James R. Mateer, and Robert E. Condon. Prospective Evaluation of
 Abdominal Sonography for the Diagnosis of Bowel Obstruction. Annals of Surgery.
 1996;223(3):237-241.
Inclusion Criteria:

 -  18 years of age or greater

 -  Abdominal pain with clinical suspicion for small bowel obstruction

 Exclusion Criteria:

 -  Less than 18 years of age

 -  Lack of decision-making capacity or cannot provide consent

 -  Pregnancy

 -  Prisoners