Abstract
Background and aimsThe underlying physiology of post-reflux swallow-induced peristaltic wave (PSPW) is unclear. We aimed to: 1) calculate the probability of a random association between reflux and PSPW; 2) characterize factors that could underlie triggering of PSPW and 3) assess the chemical clearance effect of PSPW in healthy asymptomatic subjects.MethodsA total of 251 impedance–pH tracings from healthy asymptomatic subjects were analysed. Twenty consecutive tracings from this pool with 20–40 reflux episodes/24 h and a PSPW index higher than 50% were separately analyzed to evaluate the probability of a random association between reflux and PSPW. The characteristics of reflux episodes followed by a PSPW were compared with those not associated with PSPW.ResultsA mean time interval of 29.3 s between a reflux episode and the first swallow captured 71% of total reflux episodes, and 67% of accompanying swallows were non-random. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic (P = 0.048), mixed with gas (P < 0.0001), of high proximal extent (P < 0.0001), while awake (P < 0.0001), and with shorter chemical clearance time (P = 0.040). High proximal extent, gas presence and occurring while awake were independent factors associated with PSPW (P < 0.0001).ConclusionUsing a time window between reflux and PSPW of around 30 s, the probability of a chance association is around 30%. Reflux episodes with high proximal extent, containing gas and occurring while awake are important factors associated with PSPW in healthy subjects. Reflux episodes with PSPW have a shorter chemical clearance time.
Highlights
Esophageal clearance of refluxed material is believed to be a major pre-epithelial defense mechanism against the development of gastroesophageal reflux disease (GERD) [1]
Post-reflux swallow-induced peristaltic wave (PSPW), and post-reflux swallowinduced peristaltic wave (PSPW) index are recently described metrics on impedance– pH metry relevant to GERD diagnosis and management [5], because values are lower in GERD compared to normal subjects and functional esophageal disorders [6]
Since physiology underlying PSPW remains incompletely understood, we evaluated a large number of impedance–pH tracings obtained from healthy asymptomatic subjects, to better understand relationships of PSPW to reflux episodes, triggering factors, and chemical clearance effect
Summary
Esophageal clearance of refluxed material is believed to be a major pre-epithelial defense mechanism against the development of gastroesophageal reflux disease (GERD) [1]. Immediate swallow-induced primary peristalsis, or secondary peristalsis triggered by a distensioninduced local reflex through activation of esophageal mechano-receptors, rapidly clears the bulk of the intraluminal refluxate volume, remaining residue can sustain acidification of the esophageal mucosa Chemical clearance of this residue involves a post-reflux swallowinduced peristaltic wave (PSPW), which delivers salivary. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic (P = 0.048), mixed with gas (P \ 0.0001), of high proximal extent (P \ 0.0001), while awake (P \ 0.0001), and with shorter chemical clearance time (P = 0.040). Reflux episodes with high proximal extent, containing gas and occurring while awake are important factors associated with PSPW in healthy subjects. Reflux episodes with PSPW have a shorter chemical clearance time
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