title: Validation of an ambulatory esophageal pH monitoring system.
abstract: The present study documents the accuracy of a commercially available ambulatory esophageal pH instrument. The distal esophagus of five subjects with daily heartburn was monitored for 24 h in the laboratory via an antimony pH electrode. The computer output from the ambulatory unit was compared to the on-line recording in terms of all events in which the pH dropped below four. A signal detection model was used, with an on-line pH tracing serving as the criterion response. The events noted as true positives (80%) were an accurate representation by the computer output of the events of pH less than four displayed by the on-line recording. The processing done by this particular ambulatory system tends to actually "ignore" transient pH drops (18% false negatives) and, may, in fact, provide more physiologically meaningful information than hardwired analog techniques for 24-h pH monitoring. The results confirm that ambulatory pH monitoring can produce meaningful and reliable physiological data concerning gastroesophageal reflux.
authors.affiliation: HCA Presbyterian Hospital, Oklahoma City, Oklahoma.
authors.forename: M L
authors.initials: ML
authors.lastname: Allen
authors.forename: W C
authors.initials: WC
authors.lastname: Orr
authors.forename: D M
authors.initials: DM
authors.lastname: Woodruff
authors.forename: M G
authors.initials: MG
authors.lastname: Robinson
mesh_terms: D000328:Adult; D000368:Aged; D003201:Computers; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D006356:Heartburn / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*