Accurate placement of the esophageal pH electrode for 24-hour pH monitoring using a combined pH/manometry probe

OBJECTIVE: Accurate placement of a pH electrode requires manometric localiz ation of the lower esophageal sphincter (LES). Combined manometry/pH device s using water-perfused tubes attached to pH catheters and the use of an ele ctronic "LES locator" have been reported. We investigated whether accurate placement of pH probes can be achieved using such a probe, and whether this may reduce the need for the performance of the usual stepwise pull-back ma nometry. METHODS: Thirty consecutive patients (15 men, 15 women; median age, 56 yr; interquartile range, 42-68 yr) referred for manometry and pH testing were i ncluded in the study. The localization of the LES was determined with stand ard esophageal manometry. After that, a second 3-mm pH electrode with an in ternal perfusion port was passed into the stomach. Using this catheter, a s ingle stepwise pull-through manometry was performed and the LES position wa s noted. LES location, mean pressure, and length obtained with standard man ometry were compared to data from the combined pH/manometry catheter. Addit ionally the time necessary to perform each of the procedures was noted and the patient's discomfort caused by the catheter was evaluated using a stand ardized questionnaire. RESULTS: The LES location with the pH/manometry probe was proximal to that with standard manometry in 19 patients (63%), the same in nine patients (30 %), and distal in two patients (7%). The differences were <2 cm in 29 of 30 (97%) patients. The LES location with the pH/manometry probe required a me dian of 6.5 min (interquartile range: 3.5-8.5 min) versus a median of 21.5 min (interquartile range: 14.5-26.5 min) for standard manometry (p < 0.0001 ). In addition, LES evaluation using the combined pH/manometry probe provid ed accurate data on the resting pressure, as well as overall and intraabdom inal length of the LES. All patients tolerated the combination probe better than the standard manometry probe (p < 0.001). CONCLUSIONS: Placement of the esophageal electrode for 24-h esophageal pH m onitoring using a combined pH/manometry probe is accurate. The technique is simple, timesaving, and convenient for the patients. Because it is possibl e to accurately evaluate the LES using this technique, it may even replace conventional manometry before pH probe placement. (C) 2000 by Am. Cell. of Gastroenterology.