How the Body Position Can Influence High-resolution Manometry Results in the Study of Esophageal Dysphagia and Gastroesophageal Reflux Disease

Background/Aims The body position can influence esophageal motility data obtained with high-resolution manometry (HRM). To examine whether the body position influences HRM diagnoses in patients with esophageal dysphagia and gastroesophageal reflux disease (GERD). Methods HRM (Manoscan) was performed in 99 patients in the sitting and supine positions; 49 had dysphagia and 50 had GERD assessed by 24-hour pH monitoring. HRM plots were analyzed according to the Chicago classification. Results HRM results varied in the final diagnoses of the esophageal body (EB) in patients with dysphagia (P = 0.024), the result being more distal spasm and weak peristalsis while sitting. In patients with GERD, the HRM diagnoses of the lower esophageal sphincter (LES), the esophagogastric junction (EGJ) morphology, and EB varied depending on the position; (P = 0.063, P = 0.017, P = 0.041 respectively). Hypotensive LES, EGJ type Ill (hiatal hernia), and weak peristalsis were more frequently identified in the sitting position. The reliability (kappa) of the position influencing HRM diagnoses was similar in dysphagia and GERD (LES diagnosis: dysphagia 0.32 [0.14-0.49] and GERD 0.31 [0.10-0.52], P = 0.960; EB diagnosis: dysphagia 0.49 [0.30-0.69] and GERD 0.39 [0.20-0.59], P = 0.480). The reliability in EGJ morphology studies was higher in dysphagia 0.81 (0.68-0.94) than in GERD 0.55 (0.37-0.73), P = 0.020. Conclusions HRM results varied according to the position in patients with dysphagia and GERD. Weak peristalsis was more frequently diagnosed while sitting in dysphagia and GERD. Hypotensive LES and EGJ type III (hiatal hernia) were also more frequently diagnosed in the sitting position in patients with GERD.