title: Impedance monitoring shows that posture and a meal influence gastro-oesophageal reflux composition and frequency.
abstract: Impedance monitoring determines reflux composition as liquid and/or gas, and we assess with impedance the effect of posture and a meal on reflux composition. Twenty-nine gastro-oesophageal reflux disease (GORD) patients and 10 normal volunteers underwent simultaneous impedance, manometry and pH for three 40-min periods, each 20-min upright, 10-min left side and 10-min right side. One period was fasting, and two postprandial. We found that reflux event composition on the right side was liquid-only near exclusively (93%). In contrast, 85% of reflux on the left side and 74% upright was gas-only or liquid and gas (P < 0.001). More gas-only reflux occurred fasting (80%) than postprandial (P < 0.01). Reflux composition was similar in the study groups and two postprandial periods (P > 0.25). After confirming gas reflux suppression on the right side, a pilot study assessed gastric anatomy as a cause. Five achalasia patients had fluid injected into the stomach at endoscopy, and the EG junction was submerged below liquid-only on the right side. We conclude that reflux is nearly always liquid-only on the right side where the EG junction may be below fluid. Reflux fasting is usually gas-only. Different posture and fasting times may (i) explain variations in acid exposure during pH monitoring and (ii) promote or prevent GORD symptoms.
authors.affiliation: Department of Gastroenterology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA. shays@ccf.org
authors.forename: S S
authors.initials: SS
authors.lastname: Shay
authors.forename: R
authors.initials: R
authors.lastname: Lopez
mesh_terms: D000328:Adult; D001628:Beverages; D004435:Eating / Q000502:physiology*; D017097:Electric Impedance; D005215:Fasting / Q000502:physiology; D005260:Female; D005740:Gases; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry; D010865:Pilot Projects; D019518:Postprandial Period / Q000502:physiology; D011187:Posture / Q000502:physiology*; D011859:Radiography; D013270:Stomach / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology; D013997:Time Factors
chemical_list: D005740:Gases