SIGNIFICANTLY REDUCED ACID DETECTION AT 10 CENTIMETERS COMPARED TO 5 CENTIMETERS ABOVE LOWER ESOPHAGEAL SPHINCTER IN PATIENTS WITH ACID REFLUX

Ambulatory pH monitoring of the esophagus is carried out by positionin g a pH sensor 5 cm above the lower esophageal sphincter (LES). There a re several techniques to locate the LES, and each method has a differe nt margin of error. This work used dual pH sensors to monitor simultan eously at two different levels (5 and 10 cm above the LES) in order to establish the possible magnitude of error that could arise from inacc urate placement of a pH probe. Thirty-four patients with symptoms of g astroesophageal reflux (GER) were studied. They were grouped as 20 pat ients with pathological reflux (GER group) and 14 patients with physio logical reflux, based on a reflux score derived by Johnson and DeMeest er for distal esophageal pH monitoring. When the reflux scores were co mpared, the difference between the two monitoring levels was statistic ally significant in the GER group (p < 0.001) but not in the physiolog ical reflux group (p = 0.09). In the GER group, the difference in the Johnson and DeMeester score accounted for a change in clinical diagnos is in nine of the 20 patients if the pH probe was placed at 10 cm abov e the upper margin of LES. Proximal reflux episodes (10 cm above LES) were preceded by distal reflux episodes (5 cm above LES) in 97% (878/9 01) of cases. Accurate probe placement is essential in the diagnosis o f GER.