Point of Care Ultrasound for Evaluation of Suspected Appendicitis in the Emergency Department

BACKGROUND:

Increasing concerns have been raised over the past several years regarding the degree of
radiation exposure in patients being evaluated for abdominal complaints. A deepening body of
literature supports the use of ultrasound for the evaluation of appendicitis. In particular,
ultrasound is being promoted as first line testing in the evaluation of appendicitis in
pediatric populations and adults with BMI < 25. This approach reduces the risks related to
radiation exposure and IV contrast dye. Unfortunately, in many practice settings, the
availability of radiology-based sonographers is limited and there can be significant delays
in obtaining ultrasound images. For these reasons, many ED physicians (EP) have begun to
perform bedside ultrasound to evaluate for appendicitis.

Studies have demonstrated a wide range in the accuracy of ultrasound for appendicitis.
Sensitivities and specificities vary and no standardized diagnostic criterion exist.
Additionally, little has been published directly studying EP point of care ultrasound in the
evaluation for acute appendicitis. One study has shown that EP-performed ultrasounds had a
relatively low sensitivity, but a high specificity. However, this study was performed by a
wide range of users with varying skill levels and older ultrasound machines. The surgical
literature suggests that the ability of the clinician to integrate the history, the physical
exam and the ultrasound findings in real time improves the diagnostic accuracy of ultrasound
for appendicitis.

Currently there are 4 physicians on staff in the ED who are fellowship trained in point of
care emergency ultrasound, fully credentialed and are already performing ED based evaluations
for appendicitis on a limited basis. The current standard of care is a point of care
ultrasound as first-line imaging for patients with suspected appendicitis when a credentialed
EP is available to perform the scan. We intend to evaluate the performance of EP-performed
point of care ultrasound in the diagnosis of acute appendicitis in ED patients. This study
would primarily investigate the accuracy of ultrasound as compared to the criterion standard
of either abdominal CT results or surgical pathology report.

STUDY DESIGN:

This will be a prospective, descriptive study of Emergency Department patients suspected of
having acute appendicitis. Initial screening of potential enrollees will be performed by ED
nurses, residents, and attendings. Once consented and enrolled, a study sonographer will
interview and examine the patient, preferably before lab results are available. The
ultrasound must be completed and adequate images obtained before other imaging modalities are
completed. Ultrasound of the right lower quadrant (RLQ) will performed using the graded
compression technique described previously in the literature. All participating EP
sonographers are already trained in this technique, fully credentialed and no additional
training will be performed. A "Bedside" standardized data collection form will be used at the
bedside to record ultrasound findings and clinical information. The sonographer will
designate the appendix as "not visualized", "visualized and normal", or "visualized and
abnormal" and the ultrasound as "positive for appendicitis", "negative for appendicitis" 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
overreading sonographer will record his interpretation and secondary findings on a "Blinded
Reviewer" standardized data collection sheet.

CT imaging, surgical pathology reports, and a two week telephone follow up 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.

Based on expected proportion of patients with proven appendicitis of 15% with desired
precision of 0.15, the estimated sample size for this study is 261.

STUDY POPULATION AND RECRUITMENT METHODS:

Study population will include patients of any age presenting to the emergency department with
abdominal pain and a clinical suspicion of appendicitis. Patients will initially be seen by a
treating attending physician or resident. If there is a concern for appendicitis the treating
physician will contact one of the ultrasound credentialed EP sonographers to perform a point
of care ultrasound. Of note, this is the current standard practice in the ED. By choosing to
participate in the study, the patient's treatment is not altered in any way from the current
standard practice, but simply is agreeing to allow us to collect data and contact them by
phone at the two week follow up. The study sonographer will obtain consent. Parental consent
will be obtained for patients under the age of 18.

DATA TO BE UTILIZED:

The following data will be recorded:

- Patients initials

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

- Age

- Sex

- Height

- Weight

- Symptom Duration

- Chief complaint

- Presence of RLQ pain

- Anorexia

- Migration of pain to RLQ

- Rebound tenderness

- Nausea/vomiting

- Maximum recorded temperature in the Emergency Department

- White Blood Cell (WBC) count

- Visualization of the iliac vessels?

- Visualization of the appendix?

- Maximum outer diameter of the appendix

- Thickness of the appendix wall

- Edema of the wall of the appendix?

- Peri-appendiceal edema or free fluid?

- Non compressible appendix?

- Pain with compression over the appendix?

- Evidence of dilated bowel loops in the RLQ?

- Increased vascularity of the appendix wall?

- Appendicolith?

- Free fluid in the right upper quadrant (RUQ)?

- Diagnostic impression of the sonographer

- Diagnostic impression of the blinded reviewer

- CT diagnosis

- Pathology diagnosis

- Operative report classification

- Time to disposition

- Final diagnosis

- Symptoms/Subsequent diagnosis at two weeks

DATA ANALYSIS:

For the primary outcome, data will be used to calculate the sensitivity and specificity of
point of care (POC) US for the diagnosis of appendicitis compared to the criterion standard
of CT, operative report, discharge diagnosis and two week follow up phone call.

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 who have ultrasounds highly suspicious for appendicitis 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, METHODS AND CONFIDENTIALITY:

Research records will be stored in locked offices, filing cabinets, and computers using
passwords.

SUBJECT INFORMED CONSENT:

We will seek documented informed consent and HIPAA Authorization. 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:

Burford JM, Dassinger MS, Smith SD. Surgeon-performed ultrasound as a diagnostic tool in
appendicitis. Journal of Pediatric Surgery. 2011;46;1115-1120

Estey A, Poonai N, Lim R. Appendix Not Seen: The Predictive Value of Secondary Inflammatory
Sonographic Signs. Pediatric Emergency Care. 2013;29(4):435-9.

Fox JC, Solley M, et al. Prospective evaluation of emergency physician performed ultrasound
to detect acute appendicitis. European Journal of Emergency Medicine. 2008;15:80-85.

Hulley et al. Designing Clinical Reasearch. 4th ed. Philadelphia, PA: Lippincott, Williams &
Wilkins; 2013: Chapter 6.

Karakas SP, Guelfguat M, Leonidas JC, et al. Acute appendicitis in children: comparison of
clinical diagnosis with ultrasound and CT imaging. Pediatric Radiology. 2000;30:94-8.

Pacharn P, Ying J, Linam LE, Brody AS, Babcock DS. Sonography in the Evaluation of Acute
Appendicitis: Are Negative Sonographic Findings Good Enough? Journal of Ultrasound Medicine.
2010;29;1749-1755.

Puylaert JB. Acute appendicitis: US evaluation using graded compression. Radiology.
1986;158:355-60.

Inclusion Criteria:

- RLQ pain with clinical suspicion for acute appendicitis

Exclusion Criteria:

- History of appendectomy

- Imaging prior to ED ultrasound performed to evaluate the RLQ

- Patients who are decisionally impaired or cannot provide consent