Intestinal metaplasia of the gastric cardia in a country with high Helicobacter pylori prevalance

Abstract

When performing pH monitoring, the standard recommendation is to place the pH probe 5 ern above the upper border of the LES as determined by manometry, but an alternative method, the step technique, is in common use. The step technique is based on the assumption that the shift between the acid environment of the stomach and the alkaline environment of the esophagus regularly occurs at the gastroesophageal junction, so the pH probe can then be positioned 5 em above that point. Aims: To assess the accuracy of the step technique compared with placing of pH probe by esophageal manometry. Patients and Methods: One-hundred and fifty pts underwent esophageal manometry and 24 hour pH monitoring. After manometry was completed, an investigator who was unaware of the manometric findings, placed the pH probe transnasally into the stomach and then withdrew it gradually until a pH rise >5 was identified. The distance between this point and the nares was recorded and compared with the measurement based on manometry. Results: The step technique correlated with manometry in 37 (25%) of 150 patients. In the remaining 113 (75%) pts the position differed from the upper border of the manometrically determined LES (see table). Conclusions: This study shows that the step technique for placing the pH probe was inaccurate in 75% of pts. It was placed: (a) above the correct point in 34% of pts, with the risk of false negative results if the refluxate does not reach that level; and (b) below the correct point in 66% of patients, with the risk of false positive results due to exposure to gastric juice. These data show that manometry is indispensable for placing the pH probe accurately, so it should precede every pH monitoring study.