The purpose and aim of this study are to compare changes in pulse volume to non-invasively predict active bleeding or high-risk stigmata in patients undergoing a gastrointestinal endoscopy to assess feasibility of the flow meter clinically.

The maximum change in volume of a limb segment during the cardiac cycle - pulse volume - will be monitored non-invasively along with standard vitals in patients with a suspected gastrointestinal bleed undergoing endoscopy. Pulse volume and vitals will be collected prior to and following endoscopy up to the point of dismissal from the endoscopy unit so that the data may be correlated with the endoscopic and clinical findings.

Inclusion Criteria:

- Adults (age >18yr) undergoing emergent endoscopy for active GI bleeding.

Exclusion Criteria:

• Patients with pre-existing heart failure (ejection fraction <40%), cardiac rhythm abnormalities and peripheral vascular disease.
• Patients with underlying implanted cardiac electrical devices and spinal cord stimulators.

Subjects undergoing emergent endoscopic evaluation for active gastrointestinal bleeding at Mayo Clinic, Rochester, Minnesota.