title: Determinants and clinical impact of pressure drift in manoscan anorectal high resolution manometry system.
abstract: BACKGROUND
  Pressure drift (PD), resulting from differences between room and body temperature, reduces the accuracy of pressure measurements with the Manoscan high resolution manometry (HRM) system. Our aims were to assess PD during anorectal HRM.
  
  
  METHODS
  Defined as the residual pressure measured immediately after the catheter was removed, PD was calculated for each sensor and averaged across all 12 sensors in 454 anorectal consecutive studies recorded with 3 HRM catheters. The relationship between PD and study duration, number of prior uses of a catheter, and peak and average pressure exposure during a study were evaluated. The correction of PD with a software algorithm (thermal compensation) was evaluated in 76 studies where the most distal sensor was outside the body.
  
  
  RESULTS
  The PD varied among sensors and across catheters. The average PD (7.3 ± 0.2 mmHg) was significantly greater for newer catheters, during longer studies, or when sensors were exposed to higher pressures. Together, these factors explained 81% of the variance in overall PD. After thermal compensation, the uncorrected median PD for the most distal sensor was 2.5-5 mmHg over the study duration. Correcting this changed the interpretation (e.g., as abnormal instead of normal) of at least 1 anorectal parameter in eight of 76 studies.
  
  
  CONCLUSIONS
  During anorectal HRM, PD declines with catheter use and is greater for newer catheters, when sensors are exposed to higher pressures, and for studies of longer duration. While PD is partially corrected with thermal compensation algorithms, the impact on interpretation is modest.
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.) Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: G
authors.initials: G
authors.lastname: Parthasarathy
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.) Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: J
authors.initials: J
authors.lastname: McMaster
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.) Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: K
authors.initials: K
authors.lastname: Feuerhak
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Zinsmeister
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.) Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Bharucha
mesh_terms: D000465:Algorithms; D001003:Anal Canal / Q000502:physiology*; D006801:Humans; D008365:Manometry / Q000379:methods*; D011312:Pressure; D012007:Rectum / Q000502:physiology*
keywords: anorectal manometry; constipation; fecal incontinence