title: Determinants of pressure drift in Manoscan(™) esophageal high-resolution manometry system.
abstract: BACKGROUND
  Manoscan(™) is one of the commonly used high-resolution manometry (HRM) systems with declared measurement accuracy of 1-2 mmHg. However, the accuracy of pressure measurements is limited by development of pressure drift (PD) throughout recording. To date, there has been no systematic investigation to identify the factors contributing to PD. The aim of the present study was to characterize the frequency and magnitude of PD in Manoscan(™) system and identify the factors contributing to PD.
  
  
  METHODS
  Records of 560 consecutive clinical esophageal HRM studies recorded by six distinct HRM catheters were retrospectively reviewed. PD was defined as the residual pressure measurement by each sensor immediately after removal of the catheter. Non-parametric locally weighted regression analysis was performed to assess the effect of duration of study, number of prior uses of a catheter, peak and average pressure exposure during a study on the PD.
  
  
  RESULTS
  The majority (95%) of clinical manometry studies showed a non-negligible PD of more than 5 mmHg. The overall PD was 13 ± 5 mmHg and the sensor with greatest amount of PD showed 23 ± 12 mmHg of drift. The upper esophageal sphincter showed the highest PD. Average pressure exposure of a sensor throughout the recording was the most important predictor of PD. PD inversely correlated with number of prior uses of a catheter.
  
  
  CONCLUSIONS
  The PD preferentially affects esophageal high-pressure zones, and strongly correlates with 'average pressure exposure' of a sensor during manometry. Available algorithms of the analysis software do not adequately correct the PD.
authors.affiliation: Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: A
authors.initials: A
authors.lastname: Babaei
authors.forename: E C
authors.initials: EC
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Szabo
authors.forename: B T
authors.initials: BT
authors.lastname: Massey
mesh_terms: D000465:Algorithms; D057785:Catheters; D015154:Esophageal Motility Disorders / Q000175:diagnosis*; D049631:Esophageal Sphincter, Upper / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008365:Manometry / Q000295:instrumentation* / Q000379:methods*; D011312:Pressure; D012189:Retrospective Studies
keywords: esophageal manometry; hysteresis; pressure topography; thermal compensation