Gastroscopy - The Problems Encountered

Perforation of esophagus or stomach:  

Up to 0.1% of all Esophagogastroduodenoscopy's . The upper esophagus above the cricopharynx appears most vulnerable. Other risk factors are esophageal cancer, strictures, or cervical osteophytes.

Bleeding:  

Considered rare even after biopsies, at 0.3/1000 cases. In most cases, bleeding is not due to a coagulation defect, rather it results from biopsy of friable tissue.

Cardiopulmonary complications:  

Significant cardiac arrhythmias are distinctly unusual. If a Holter monitor is placed, transient rhythm disturbances such as sinus tachycardia, premature ventricular contractions (PVCs), premature atrial contractions (PACs), and rarely ischemic changes may be recorded in 22% of cases. Few adverse clinical outcomes have been reported.

Lung infections due to vomiting and aspiration during the procedure.