Study was not approved by the institution's scientific committee.

Emergency room patients referred for esophago-gastro-duodenoscopy (EGD) often have many possible causes for their symptoms. These patients inevitably undergo further testing if EGD is inconclusive, which adds costs and prolongs emergency room length of stay (LOS).EUS has traditionally been used after EGD for a myriad of reasons that no longer apply. The investigators therefore propose a prospective pilot study to determine whether adding primary EUS to EGD can reduce LOS and resource utilisation in emergency room patients referred for EGD.

Emergency room patients referred for esophago-gastro-duodenoscopy (EGD) often have many possible causes for their symptoms. These inevitably undergo further testing if EGD is inconclusive, which adds costs and inevitably prolongs emergency room length of stay (LOS).

Endoscopic ultrasound (EUS) combines EGD with high-resolution ultrasound imaging of pancreas, liver and biliary system and is the best test to diagnose bile duct stones, early chronic pancreatitis, and small [<2cm] pancreatic cancers (all of which cannot be seen by regular ultrasound or CT scanning or MRI, yet are included in the differential diagnosis of EGD-negative abdominal pain).

EUS has traditionally been used after EGD, due to lack of availability, increased cost, and to increased risk due to larger scope diameter. However, the latest generation of EUS scopes have the same outer diameter as conventional gastroscopes, there is much wider availability of EUS in university and community hospital settings, and the cost per procedure is lower, due to increased procedural numbers and reduced maintenance costs.

In experienced hands, diagnostic EUS is now as safe and as accurate as EGD for diagnosing mucosal pathology and takes approximately 1 minute longer.(1; 2) Previously published work by our group suggests that EUS may reduce resource consumption in patients with unexplained abdominal pain.(3) The investigators also showed that in refractory dyspepsia with normal EGD and CT, EUS identified signs of occult chronic pancreatitis in up to 20% of cases.(4) More recently, EUS was found to identify previously undiagnosed, potential causes of unexplained abdominal pain in up to 9% of patients, or at least provides the same, if not more information than EGD and abdominal US alone.(2; 5; 6)

There are no previous studies that have prospectively compared the yield of EGD and PEUS in emergency room patients. The investigators hypothesize that adding EUS to EGD ("primary EUS" [PEUS]) can safely and more efficiently diagnose or exclude significant gastro-intestinal and pancreatico-biliary pathology in emergency room patients in whom EGD has been requested. The investigators therefore propose a prospective pilot study to perform a preliminary analysis of the potential impact of PEUS on the ability to make an early GI diagnosis (EGID), length of stay (LOS) and resource utilisation in emergency room patients referred for EGD. If there is sufficient evidence of a clinically useful impact, an appropriately powered study to determine whether PEUS is clinically superior to EGD with respect to these variables will be performed.

Inclusion Criteria:

1. EGD requested by the consulting gastroenterologist
2. Informed consent

Exclusion Criteria:

1. Evidence of hemodynamic instability and/or ongoing active GI bleeding.
2. Any suspicion of obstruction distal to the angle of Treitz.