title: Oesophageal acid clearance in patients with systemic sclerosis: effect of body position.
abstract: OBJECTIVE
  To test the effect of body position on oesophageal acid clearance time in patients with systemic sclerosis.
  
  
  METHODS
  Fifteen consecutive patients with systemic sclerosis and six healthy subjects underwent oesophageal manometry and an acid clearance test in three body positions (supine, recumbent at 30 degrees and seated at 90 degrees) in randomized order.
  
  
  RESULTS
  In healthy subjects the body position did not affect acid clearance time, whereas in patients the oesophagus cleared mainly by gravity. In patients the acid clearance time was significantly longer in the supine than in the seated position (P < 0.05). Nine patients did not have a detectable peristaltic wave in the distal oesophagus. In the other six oesophageal peristalsis was still detectable but contractions had reduced amplitude and often had double and triple peaks; also in this subgroup the acid clearance time recorded in the supine position was prolonged.
  
  
  CONCLUSIONS
  In systemic sclerosis gravity plays a major role in oesophageal acid clearance time. The finding of delayed acid clearance in a supine patient may suggest initial oesophageal involvement in the disease.
authors.affiliation: Department of Gastroenterology, IRCCS Ospedale Maggiore, Università degli Studi di Milano, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Basilisco
authors.forename: F
authors.initials: F
authors.lastname: Carola
authors.forename: M
authors.initials: M
authors.lastname: Vanoli
authors.forename: P
authors.initials: P
authors.lastname: Bianchi
authors.forename: R
authors.initials: R
authors.lastname: Barbera
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003679:Deglutition; D003680:Deglutition Disorders / Q000503:physiopathology; D015154:Esophageal Motility Disorders / Q000503:physiopathology; D004941:Esophagitis / Q000503:physiopathology; D004943:Esophagogastric Junction / Q000503:physiopathology; D004947:Esophagus / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology; D006112:Gravitation; D006356:Heartburn / Q000503:physiopathology; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006863:Hydrogen-Ion Concentration; D007440:Intubation; D008297:Male; D008365:Manometry; D008875:Middle Aged; D010528:Peristalsis; D011187:Posture; D012595:Scleroderma, Systemic / Q000503:physiopathology*; D016683:Supine Position; D013997:Time Factors
chemical_list: D006851:Hydrochloric Acid