title: Prolonged intraesophageal pH monitoring with 16-hr overnight recording. Comparison with "24-hr" analysis.
abstract: From studies in 43 patients (17 male, 26 female, mean age 51 years), we compared the analysis of the routine complete "24-hr" ambulatory esophageal pH monitoring study to that of the 16-hr overnight interval (4:00 PM to 8:00 AM). The latter included a major meal with an upright postprandial period and a recumbent period. All patients were monitored for at least 20 hr (median = 22.6 hr). The percent distal esophageal pH less than 4.0 and number of reflux episodes were measured for the total, upright, and recumbent periods of both the 16-hr and "24-hr" monitoring times. Significant (P less than 0.001) positive correlations were found for all comparisons between the two monitoring periods including percent time of pH less than 4.0 (total: r = 0.98; upright: r = 0.96) and number of episodes (totals r = 0.97; upright: r = 0.93). Patients were separated into normal and abnormal refluxers based on results of "24-hr" monitoring (pH below 4.0 greater than 4.2% total time; greater than 6.0% upright; greater than 1.2% recumbent). Based on this, sensitivity and specificity for 16-hr monitoring were as follows: total study: 86% and 95%; upright: 80% and 91%; recumbent: 100% for both.
  
  
  CONCLUSIONS
  (1) a 16-hr overnight pH monitoring period can provide a reliable representation of "24-hr" distal esophageal acid exposure, (2) this shorter monitoring may improve patient acceptability and compliance, and (3) the symptom index was changed in 26.3% of patients using the 16-hr evaluation.
authors.affiliation: Jefferson Medical College, Philadelphia, Pennsylvania.
authors.forename: R
authors.initials: R
authors.lastname: Dobhan
authors.forename: D O
authors.initials: DO
authors.lastname: Castell
mesh_terms: D004566:Electrodes; D004942:Esophagitis, Peptic / Q000175:diagnosis*; D004947:Esophagus / Q000378:metabolism*; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011187:Posture; D012680:Sensitivity and Specificity; D013997:Time Factors