Mechanisms of intestinal gas retention in humans: impaired propulsion versus obstructed evacuation

Abstract

To explore the clinical role of intestinal gas dynamics, we investigated two potential mechanisms of gas retention, defective propulsion and obstructed evacuation. In healthy subjects, a gas mixture was continuously infused into the jejunum (4 ml/min) 1) during a 2-h control period of spontaneous gas evacuation and 2) during a 2-h test period either with impaired gut propulsion caused by intravenous glucagon ( n = 6) or with obstructed (self-restrained) anal evacuation ( n = 10) while anal gas evacuation, sympton perception (0–6 scale), and abdominal girth were measured. Impaired gut propulsion and obstructed evacuation produced similar gas retention (558 ± 68 ml and 407 ± 85 ml, respectively, vs. 96 ± 58 ml control; P < 0.05 for both) and abdominal distension (8 ± 3 mm and 6 ± 3 mm, respectively, vs. 1 ± 1 mm control; P < 0.05 for both). However, obstructed evacuation increased symptom perception (2.3 ± 0.6 score change; P < 0.05), whereas gas retention in the glucagon-induced hypotonic gut was virtually unperceived (−0.4 ± 0.7 score change; not significant). In conclusion, the perception of intestinal gas accumulation depends on the mechanism of retention.