Primary peristalsis is the major acid clearance mechanism in reflux patients.

Abstract

This study examined the clearance of gastric acid from the oesophagus in ambulant patients with gastrooesophageal reflux. Eighteen patients with proved reflux disease were studied, nine with (group 1) and nine without (group 2) endoscopic oesophagitis. Oesophageal pressure and pH were recorded over 24 hours. Pressures were measured by a probe with five sensors: a 5 cm long sensor in the lower oesophageal sphincter, three sensors in the body of the oesophagus, and one at the pharynx to detect swallowing. Oesophageal pH was monitored 5 cm above the lower oesophageal sphincter. Manometric activities were classified as either peristaltic or ineffective. The latter included simultaneous, non-transmitted, and low amplitude peristaltic contractions. A reflux episode was defined as starting when pH fell to less than 4 and ending when the pH rose to 5. When the rise to pH 5 took place in three or more discrete steps after motor responses to gastrooesophageal reflux, the pH steps were labelled as initial change (I), middle changes (M), and last change (L). A total of 595 episodes of gastro-oesophageal reflux and 1626 associated motor events were analysed. Of these, 1331 (81-9%) were classed as primary peristaltic activity, 174 (10-7%) as primary ineffective activity, 46 (2.8%) as secondary peristaltic activity, and 75 (4-6%) as secondary ineffective activity. There were no significant differences in initial change (p>O05), middle changes (p>005), and last change (p>005) between group 1 and group 2. In all patients, the successive changes of pH in response to motor activity were significantly different (p=0-0001) between initial, middle, and last changes. Last change was significantly higher when compared with initial (p=0001) and middle changes (p<0001). Primary oesophageal peristalsis was the most frequent motor response to gastrooesophageal reflux. The last motor activity during reflux showed the greatest change in pH.

The Spectrum of Motor Function Abnormalities in Gastroesophageal Reflux Disease and Barrett’s Esophagus

“…Acid clearance is a two-step process: swallowing and primary peristalsis aids in the transport of alkaline saliva to the distal esophagus, whilst secondary peristalsis is necessary for the clearance of the bulk of the refluxate. A longer delay from the onset of the reflux event to the initial clearing event has been shown in patients with reflux disease compared to controls [44]. Barham et al [45] reported even longer acid clearance time in patients with reflux strictures.…”

“…Primary peristalsis is the initial response to acid reflux in normal subjects when in the upright position, whereas secondary peristalsis is the initial clearing event when subjects are supine and asleep [22, 23, 44, 46, 47]. Impairment of primary peristalsis is evident by the increased time to onset of the peristaltic response, fewer number of peristaltic events, increased time interval between peristaltic events, low-amplitude peristaltic contractions, simultaneous contractions and a lower number of complete peristaltic sequences in reflux patients compared to healthy subjects [45, 46, 48].…”

Laparoscopic fundoplication improves oesophageal motility – a prospective study

“…In studies on peristaltic wave efficacy it was found that the peristaltic wave is effective, i.e. it pushes the food bolus towards the stomach, if the contraction amplitude in the proximal part is not lower than 16 mmHg, and in the distal part 30 mmHg [22,23]. In a considerable number of patients with reflux disease the oesophageal motility is impaired [22,24,25].…”

“…it pushes the food bolus towards the stomach, if the contraction amplitude in the proximal part is not lower than 16 mmHg, and in the distal part 30 mmHg [22,23]. In a considerable number of patients with reflux disease the oesophageal motility is impaired [22,24,25]. Motility impairment is present in about 25% of patients with mild GERD and in about 50% of patients with severe form of the disease [12,26].…”

Esophageal Acid Clearance During Random Swallowing Is Faster in Patients with Barrett‘s Esophagus Than in Healthy Controls

“…In this event, esophageal acid clearance in normal subjects usually restores a normal pH within 3-5 minutes. 5 First, esophageal peristalsis clears the majority of the acid ("volume clearance"), 6 and secondly bicarbonate-containing saliva neutralizes any remaining acid by "chemical clearance". 7 Both of these mechanisms are believed to be activated and regulated via reflexes triggered by esophageal acidification and distension.…”