title: Gastroesophageal pH step-up inaccurately locates proximal border of lower esophageal sphincter.
abstract: Limiting the widespread use of 24-hr pH monitoring is the necessity of manometrically placing the pH probe 5 cm above the proximal lower esophageal sphincter (LES) border. Therefore, we prospectively compared LES localization by gastroesophageal pH step-up with manometry in 71 patients and 14 asymptomatic volunteers. The gastroesophageal pH step-up significantly correlated with the proximal LES border in patients (r = 0.53, P less than 0.0001) and volunteers (r = 0.91, P less than 0.0001). Based on previously published criteria, the pH step-up value was considered acceptably accurate if it was within +/- 3 cm (6 cm total span) of the manometrically determined proximal LES border. In 58% of patients and 29% of volunteers the pH step-up occurred outside this accuracy range. Esophagitis (P = 0.015) and abnormal reflux parameters (P = 0.002) were variables contributing to this error. Subsequent analysis found that the pH step-up overestimated the proximal LES border and occurred at the midportion of the sphincter. The pH step-up still inaccurately located the mid LES in 34% of patients. Therefore, manometry should remain the standard for accurate LES localization prior to placing the pH probe.
authors.affiliation: Division of Gastroenterology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27103.
authors.forename: H E
authors.initials: HE
authors.lastname: Mattox
authors.forename: J E
authors.initials: JE
authors.lastname: Richter
authors.forename: J W
authors.initials: JW
authors.lastname: Sinclair
authors.forename: J E
authors.initials: JE
authors.lastname: Price
authors.forename: L D
authors.initials: LD
authors.lastname: Case
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D002940:Circadian Rhythm / Q000502:physiology; D016001:Confidence Intervals; D004943:Esophagogastric Junction / Q000503:physiopathology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D011446:Prospective Studies; D012044:Regression Analysis; D015203:Reproducibility of Results