title: Gastric and lower esophageal sphincter pressures during nausea: a study using visual motion-induced nausea and high-resolution manometry.
abstract: Nausea is the subjective unpleasant sensation that immediately precedes vomiting. Studies using barostats suggest that gastric fundus and lower esophageal sphincter (LES) relaxation precede vomiting. Unlike barostat, high-resolution manometry allows less invasive, detailed measurements of fundus pressure (FP) and axial movement of the gastroesophageal junction (GEJ). Nausea was induced in 12 healthy volunteers by a motion video and rated on a visual analog scale. FP was measured as the mean value of the five pressure channels that were clearly positioned below the LES. After intubation, a baseline (BL) recording of 15 min was obtained. This was followed by presentation of the motion video (at least 10 min, maximum 20 min) followed by 30 min recovery recording. Throughout the experiment we recorded autonomic nervous system (ANS) parameters [blood pressure, heart rate (HR), and cardiac vagal tone (CVT), which reflects efferent vagal activity]. Ten out of 12 subjects showed a drop in FP during peak nausea compared with BL (-4.0 ± 0.8 mmHg; P = 0.005), and 8/10 subjects showed a drop in LES pressure (-8.8 ± 2.5 mmHg; P = 0.04). Peak nausea preceded peak fundus and LES pressure drop. Nausea was associated with configuration changes at the GEJ such as LES shortening and esophageal lengthening. During nausea we observed a significantly increased HR and decreased CVT. In conclusion, nausea is associated with a drop in fundus and LES pressure, configuration changes at the GEJ as well as changes in the ANS activity such as an increased sympathetic tone (increased HR) and decreased parasympathetic tone (decreased CVT).
authors.affiliation: Neurogastroenterology Group, Center for Digestive Diseases, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors.forename: Nora
authors.initials: N
authors.lastname: Schaub
authors.forename: Kee
authors.initials: K
authors.lastname: Ng
authors.forename: Paul
authors.initials: P
authors.lastname: Kuo
authors.forename: Qasim
authors.initials: Q
authors.lastname: Aziz
authors.forename: Daniel
authors.initials: D
authors.lastname: Sifrim
mesh_terms: D001794:Blood Pressure; D003679:Deglutition; D049630:Esophageal Sphincter, Lower / Q000294:innervation / Q000503:physiopathology*; D005260:Female; D005748:Gastric Fundus / Q000294:innervation / Q000503:physiopathology*; D005764:Gastroesophageal Reflux / Q000209:etiology / Q000503:physiopathology; D005769:Gastrointestinal Motility; D064368:Healthy Volunteers; D006339:Heart Rate; D006801:Humans; D007441:Intubation, Gastrointestinal; D008297:Male; D008365:Manometry; D009041:Motion Sickness / Q000209:etiology / Q000503:physiopathology*; D010775:Photic Stimulation; D011312:Pressure; D012472:Salivation; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013997:Time Factors; D014630:Vagus Nerve / Q000503:physiopathology; D014741:Video Recording; D055815:Young Adult
keywords: gastric fundus and lower esophageal sphincter pressure; high-resolution manometry; motion video-induced nausea