Evidence basesd guidelines for preparation of patients before upper gastrointestinal endoscopy(UGIE)

Abstract

Upper gastrointestinal endoscopy (UGIE) is a very common investigation world wide. Although various societies have guidelines for preparation of patients before upper GI endoscopy, many of these are based on scanty evidence. We set out to establish a set of guidelines that were both evidence based and suitable for an Asian setting. Current guidelines for patients undergoing UGIE advice at least 6-8 hours fasting for solids and at least 4 hours for liquids. This is claimed to ensure safety and a clear endoscopic view. However, prolonged fasting may result in patient discomfort and undue stress. Due to practical delays the fasting period for endoscopy can become much longer than the stipulated six hours, thus causing even more patient discomfort. This may become especially difficult to tolerate for patients with gastro-esophageal reflux disease (GERD). Physiological studies have shown that clear fluids leave the stomach rapidly, and several anesthetic guidelines now recommend a 2-hour pre-operative fast for clear fluids and a 6-hour fast for solids before general anesthesia..We studied if a one hour fast for water was sufficient prior to upper UGIE and have shown that a one hour fast for water is sufficient prior to UGIE. This helps to alleviate patient discomfort and should be incorporated in the new guidelines. The six hour fast for solids prior to UGIE advised in most guidelines favours a western diet. In our second study we set out to examine if this was sufficient in the Asian context where the diet is mainly rice based. In a small pilot study we first used real time ultrasound to determine the exact time taken for a standard rice meal to empty from the stomach. It was found to be ten hours. We then conducted a large trial to test our hypothesis. We found that a six hour fast is inadequate for a rice based meal and actually patients should fast at least 10 hrs prior to endoscopy if they consume a rice based meal. This too should be included in the new guidelines especially in the Asian setting.