Background The Chicago Classification (CC) of Esophageal Motility Disorders is based on 10 water swallows performed in the supine position. The aim of the study was to assess whether upright and provocative swallows (PS) provided important information beyond that obtained from the standard supine manometric protocol.
Methods Two independent investigators reviewed high-resolution manometry (HRM) studies of 148 patients with both supine and upright liquid swallows and additional studies from patients with PS (increased volume, viscosity, and a marshmallow) for a resultant change in CC diagnoses. Significant diagnostic changes were defined as a change from normal or borderline motor function to abnormal motor function, esophagogastric junction (EGJ) outflow obstruction, or achalasia. Discordant diagnoses were reviewed and the Kappa test was used to evaluate the agreement between diagnoses in the different protocols.
Key Results The overall agreement in diagnosis between the five supine swallows and the five upright swallows was good (k = 0.583). Changing to the upright position elicited a significant diagnostic change in 10.1% (15/148) of cases. The PS suggested an alternative diagnosis from the supine position in 14 of 75 studies (18.7%); 11 of these changed to EGJ obstruction during viscous or solid bolus challenges.
Conclusions & Inferences Changing position in HRM elicited a significant change in diagnosis in about 10% of studies, whereas provocative bolus challenges with viscous liquid and marshmallows increased the detection of EGJ outflow obstruction. Performing manometric evaluations in both positions with PS may increase the yield of standard HRM technique.