Smaller CO2 injection volume and lower gastric pressure induce bothersome symptoms in drug-resistant functional dyspepsia patients with less frequent belching

Background The relationship between bothersome symptoms and gastric pressure or CO2 injection volumes in drug-resistant functional dyspepsia (FD) patients remains unknown; therefore, this relationship was examined in drug-resistant FD and non-FD patients. Methods Thirty drug-resistant FD patients and 30 non-FD patients were recruited. Gastric pressure was assessed using an external pressure transducer, and the CO2 injection volume was measured using an endoscopic CO2-supplied device and flow meter. The following variables were examined: gastric pressure at baseline and gastric pressure and the CO2 injection volume when patients initially felt abdominal tension and bothersome symptoms following the CO2 injection. The relationship between belching and bothersome symptoms was also investigated. Results No significant differences were observed in basal gastric pressure between the groups. Initial and bothersome symptoms in the upper abdomen in drug-resistant FD patients developed at a significantly lower gastric pressure and significantly smaller CO2 injection volume than in non-FD patients. The frequency of belching was significantly lower in the drug-resistant FD group than in the non-FD group. Conclusion Bothersome symptoms in drug-resistant FD patients develop at a lower gastric pressure and smaller CO2 injection volume than in non-FD patients. These patients also had difficulties with belching.