Simultaneous two level oesophageal pH monitoring in healthy controls and patients with oesophagitis: comparison between two positions.

Abstract

For oesophageal pH monitoring, the pH probe is usually positioned 5 cm above the lower oesophageal sphincter (LOS). This is by convention, and has not been compared with other positions in its ability to discriminate between physiological and abnormal acid reflux. Using simultaneous two level 24 hour pH monitoring (5 and 10 cm above manometrically determined LOS) in 31 controls and 51 patients with reflux oesophagitis, the significance of the precise position ofthe probe in the oesophagus was examined. Secondly, this study compared the discrimination between the two groups achieved at the two levels. Patients had greater acid exposure than controls at both levels. In controls, acid exposure was greater at distal than at the proximal level except the supine acid exposure, which was similar at both levels. In patients, acid exposure was greater at the distal level for all variables (median % of total time pH <4=11-7 v 7-6; p=0001). There was excellent correlation between the two levels for all variables in controls (r=0-883, 0935, 0-813, and p<0001 for percentage of time pH <4 for total, supine, and upright times) as well as in patients (r=0-848, 0-848, 0 779, and p<0001). On discriminant and receiver operating characteristic analysis, pH threshold 4 seemed as good as or better than other pH thresholds in discriminating between controls and patients. The percentage of total time pH below 4 seemed to discriminate as well or better than other variables at both levels. The distal level (5 cm above LOS) provided slightly better discrimination than proximal level (10 cm) (percentage of subjects correctly classified=81-7 v 75.6). The critical factor for the reliability of the test is not the precise position of the pH probe relative to the LOS, but that the same position is consistently used in patients and controls.

Dynamic Characteristics of Gastro-oesophageal Reflux in Ambulatory Patients with Gastro-oesophageal Reflux Disease and Normal Control Subjects

“…In agreement with data reported in the literature (13,14), we found a gradual decrease in oesophageal acid exposure time and in the number of reflux episodes from distal to proximal oesophageal levels, in both healthy volunteers and GORD patients.…”

Studies of acid exposure immediately above the gastro-oesophageal squamocolumnar junction: evidence of short segment reflux

“…All parameters of oesophageal acid exposure were substantially higher at the more distal site, generating a much higher DeMeester score of 45 (range 12-131) compared with 8 (range [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Our findings indicate that acid may reflux onto the most distal squamous oesophageal mucosa without extending more proximally.…”

“…Consequently, the DeMeester score (derived from the number of reflux episodes and per cent time pH ,4) calculated from the pH data recorded close to the squamocolumnar junction was significantly greater than at the conventional position (45 (range 12-131) v 8 (range [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]; p,0.001) (table 1). The median pH nadir recorded during reflux episodes was lower close to the squamocolumnar junction than at the conventional site (pH 2.0 (range 1.4-2.6) v 2.9 (range 1.9-4.0); p,0.01) (table 3).…”

Ösophageale Refluxdiagnostik – pH-Metrie, Impedanzmessung, Bilirubin-Messung: Empfehlungen der Deutschen Gesellschaft für Neurogastroenterologie und Motilität und der Arbeitsgruppe Neurogastroenterologie der Deutschen Gesellschaft für Verdauungs- und Stoffwechselkrankheiten

“…Bei 2-Kanal-Messungen im Ösophagus können die Messaufnehmer 5 und 10 cm [175,178,180], 5 und 15 cm [176] oder 5 und 20 cm [196] oral des Oberrands des gastroösophagealen Sphinkters platziert werden. Bei Messungen in Ösophagus und Pharynx sollten die Messelektroden 2 cm oral sowie 13 cm aboral der Mitte der manometrisch festgestellten Hochdruckzone im pharyngoösophagealen Sphinkter bei Verwendung einer Sonde mit vorgegebenem Abstand der Elektroden [197] bzw.…”