LAUSR

Laryngopharyngeal reflux disease (LPRD) is currently defined as an inflammatory condition of the upper aerodigestive tract tissues related to the direct and indirect effects of gastroduodenal content reflux, whichmay induce morphologic changes in the upper aerodigestive tract. The pH of gastric contents is lower, which mainly causes acid reflux, while the pH of duodenal contents is higher than that of gastric contents, which can cause weakly acid reflux or alkaline reflux. Because carbonic anhydrase in the esophageal mucosa can convert CO2, a product of cell metabolism, into bicarbonate, which plays a role in neutralizing gastric acid. Therefore, part of gastric acid reflux or duodenal contents reflux has a pH of less than 4 at the distal esophagus, but when it reaches the hypopharynx, the pH is greater than 4 and is converted to weakly acid or alkaline reflux. Therefore, using 24-h multichannel intraluminal impedance-pH (MII-pH) monitoring, laryngopharyngeal reflux (LPR) events are divided into the following categories according to the difference of pH in hypopharynx: (1) Acid LPR when pH was 4; (2) Weakly acid LPR when pH was 4 to 7; (3) Alkaline LPR when pH above 7. Bothweakly acid and alkaline LPRwere called non-acid reflux. According to the pH value of the distal esophagus and hypopharynx, non-acid reflux can be further divided into true non-acid reflux (pH >4 in both the distal esophagus and hypopharynx) and false non-acid reflux (pH 4 in the distal esophagus, but pH >4 in the hypopharynx) [Figure 1]. However, for each patient, the proportion of the true non-acid, false non-acid, and acid reflux of the LPR events is helpful to the develop a treatment plan. If true non-acid reflux events accounts for themajority of LPR events, then acid suppressive therapy is not the main one. If false non-acid reflux and acid reflux are dominant, then acid suppressive therapy is still very important. However, there are few studies on this classification of proportion in the literature, so we aimed to analyze the 24-h MII-pH data of 50 patients with suspected LPRD in order to understand the proportion of all kinds of LPR, which may be helpful to make the treatment plan of LPRD.