A team from the Autonomous University of Barcelona, Barcelona, Spain investigated intestinal gas transit and tolerance in irritable bowel syndrome (IBS) patients compared with healthy subjects.
A gas mixture (N2, O2, and CO2 in venous proportions) was infused into the jejunum of 20 patients with IBS and 20 healthy controls, at 12 ml/min for 4 hours.
Gas evacuation, initially flatus from the anus (2 hours) and then intrarectally (2 hours), was continuously recorded. Symptom perception (0-6 scale) and abdominal distension were measured at 10-minute intervals.
18 out of 20 IBS patients, compared to 4 out of 20 controls, had impaired intestinal gas transit and tolerance.
The team found that after 2 hours of external gas (flatus) collection, 18 of 20 IBS patients had developed gas retention (>400 ml), increased gastrointestinal symptoms (score >3), or abdominal distension (>3 mm girth increment). Only 4 of the 20 control subjects developed such symptoms.
During intrarectal gas collection, 13 of 17 patients still exhibited abnormal responses.
Dr F. Azpiroz concluded on behalf of the group that, "A large proportion of patients with IBS can be shown to have impaired transit and tolerance of intestinal gas loads. This anomaly may represent a possible mechanism of IBS symptoms, specifically pain and bloating."