Which of the following statement(s) is/are true concerning other tests available for investigation of esophageal disease?

a. A 24 hour pH monitoring is currently the principal method in making the diagnosis of gastroesophageal reflux disease (GERD)

e. Delayed gastric emptying may be an important etiologic factor in patients with GERD

The development of 24 hr pH monitoring was a major advance in unraveling the pathophysiology of GERD. It is now the principal method to make the diagnosis of GERD and has effectively replaced all other methods of measuring esophageal acid exposure. It is indicated in any patient with symptoms suggesting GERD, unless the symptoms are trivial, or permanently abolished by a short course of acid suppression therapy. Reflux episodes are defined as periods when the esophageal pH is less than pH 4. Normal (physiologic) reflux occurs in the form of short rapidly cleared postprandial episodes. A few episodes of long duration are more injurious than many brief episodes, even though total acid exposure time may be similar. In addition to the measurement of acid exposure, pH monitoring can also be used to detect excessive alkaline exposure (pH > 7) in the esophagus. The Bernstein test, in which hydrochloric acid is dripped into the esophagus via a nasogastric tube, is sometimes used to determine if a patient’s symptoms are reproduced by acidic exposure. It is basically a measure of esophageal mucosal sensitivity. It has been largely superseded by the use of 24 hr pH monitoring. Gastric emptying is affected by the composition and consistency of the ingested meal. Delayed gastric emptying may be an important etiologic factor in patients with GERD and a normal LES.