Pretty much what Bakasi said. When they do pH or motility probes, they measure the number of times/hour that acidic material is detected refluxing up into the esophagus.
The issue with GERD isn't really how acidic the material (stomach acid is always going to be acidic), the issue is how often the lower esophageal sphincter loses its tone and allows the acidic contents to move back up into the esophagus.
Surgical procedures can change the actual inlet to the stomach - Nissens, Thals, etc. Medications for reflux make the material less acidic, but have much less effect on how often the material makes it back in to the esophagus.
DS had a Nissen? Is that right? Glad he's doing better!
Jill
