Relationship between the mechanism of gastro‐oesophageal reflux and oesophageal acid exposure in patients with reflux disease

Abstract

This study investigated the relationship between the oesophageal acid exposure time and the underlying manometric motor events in patients with gastro-oesophageal reflux disease (GORD). In 31 patients, 3-hour oesophageal motility and pH were measured after a test meal. Ten patients underwent 24-hour ambulatory manometry and pH recording. In the 3-hour postprandial study, of 367 reflux episodes 79% was associated with a transient lower oesophageal sphincter relaxation (TLOSR), 14% with absent basal lower oesophageal sphincter (LOS) pressure and the remaining 7% with other mechanisms, representing 62, 28 and 10% of the acid exposure time, respectively. Acid reflux duration per motor mechanism was longer for absent basal LOS pressure than for TLOSR (189 +/- 23 s and 41 +/- 5 s, respectively, P < 0.001). In the 24-hour ambulatory study, the contribution of TLOSRs to reflux frequency vs acid exposure time were 65 vs 54% interprandially and 74 vs 53% after the meal. During the night, absence of basal LOS pressure accounted for 36% of reflux events representing 71% of acid exposure time. In conclusion, the duration of oesophageal acid exposure following a TLOSR is shorter than reflux during absent basal LOS pressure. TLOSRs are, the major contributor to oesophageal acid exposure during the day. At night, however, reflux during absent basal LOS pressure is the major contributor to acid exposure.

Control of esophageal distension-induced secondary peristalsis by the GABAB agonist baclofen in humans

“…As in previous studies in animal model, 14 the increase in basal LES pressure by baclofen was abolished by vagotomy, indicating that baclofen may decrease the central vagal inhibitory modulation on the LES 14 . Baclofen appears to be able to modify and strengthen the barrier function of the LES and consequently improve hypotensive or absent LES pressure, which is thought to be the major contributor to pathological esophageal acid exposure in a subgroup of patients with reflux diseases 30 …”

Effect of baclofen on oesophageal motility and transient lower oesophageal sphincter relaxations in GORD patients: a 48‐h manometric study

“…15 Furthermore, a reduced or absent LOSP at night is recognized as the major contributor to oesophageal acid exposure. 16 In our recordings during the whole 24 h, the tone of LOS was greater in patients assuming baclofen than in the control group. This seems to indicate that baclofen is able to reinforce the barrier function of the LOS independently from all its physiological changes occurring during the entire day.…”

“…Lower oesophageal sphincter pressure is not constant during the 24 h; it is well known, in fact, that the LOSP tends to fall after a test meal, 14 there is evidence as well of a relationship between the cyclic interdigestive motor activity, particularly the phase III of MMCs, and the basal activity of LOS 15 . Furthermore, a reduced or absent LOSP at night is recognized as the major contributor to oesophageal acid exposure 16 . In our recordings during the whole 24 h, the tone of LOS was greater in patients assuming baclofen than in the control group.…”

Increased intragastric pressure gradients are involved in the occurrence of acid reflux in gastroesophageal reflux disease

“…For each TLESR the presence or absence of associated acid reflux was noted. An acid reflux event was defined as pH B4 for at least 3 s with a rate of fall of 0.5 pH units per second or, if esophageal pH was already below 4, a further decrease in pH of at least 1 pH unit sustained for at least 3 s [14]. The borders of the EGJ were identified, using the abrupt transitions in pressure topography.…”