Colonic gas transit in patients with bloating: the effect of an electromechanical stimulator of the abdominal wall

The aim of our study was to evaluate gas retention, abdominal symptoms and changes in girth circumference in females with bloating using an active or sham abdominal wall mechanical stimulation. In 14 female patients, complaining of bloating (11 with irritable bowel syndrome and 3 with functional bloating according to the Rome III criteria) a gas mixture was continuously infused into the colon for 1 h (accommodation period). Abdominal perception and girth were measured. At the beginning of the 30-min period of free rectal gas evacuation (clearance period), an electromechanical device was positioned on the abdominal wall of all patients. The patients were randomly assigned to an active or a sham stimulation protocol group. Gas retention, perception and abdominal distension were measured at the end of the clearance period. All patients tolerated the volume (1,440 ml) of gas infused into the colon. Abdominal perception and girth measurements was similar in both groups during the accommodation period. At the end of the clearance, the perception score and the girth changes in the active and sham stimulation groups were similar (2.8 +/- A 2.0 vs. 1.4 +/- A 1.2, p = 0.2 and 4.9 +/- A 4.5 vs. 2.8 +/- A 2.3 mm, p = 0.3 active vs. sham, respectively). Furthermore, the mechanical stimulation of the abdominal wall did not significantly reduce gas retention (495 +/- A 101 ml vs. 566 +/- A 55, active vs. sham, p = 0.1). An external mechanical massage of the abdominal wall did not improve intestinal gas transit, abdominal perception and abdominal distension in our female patients complaining of functional bloating.