How Much Pharyngeal Exposure Is “Normal”? Normative Data for Laryngopharyngeal Reflux Events Using Hypopharyngeal Multichannel Intraluminal Impedance (HMII)

Abstract

Background Laryngopharyngeal reflux (LPR) can cause atypical symptoms, asthma, and pulmonary fibrosis. The aim of this study was to establish the normative data for LPR using hypopharyngeal multichannel intraluminal impedancepH (HMII). Methods Asymptomatic subjects underwent endoscopy followed by 24-h HMII using a specialized impedance catheter configured to detect LPR before and after a 2-week course of proton pump inhibitors (PPI). Subjects were excluded if they had esophageal pathology or a positive DeMeester score. A cohort of 24 LPR patients who had a complete response to treatment was used for comparison with the normative data. Results Forty subjects were enrolled. Thirty-four subjects completed one, and 25 completed both HMII testing periods off and on PPI. There was no difference in the total number of reflux events between off and on PPI [22 (8–32) and 24 (10–28), respectively, p=0.89]. The 95th percentiles of LPR off and on PPI were 0 and 1, respectively. All patients with treatment responsive LPR had pre-treatment HMII values of LPR greater than the 95th percentile. Conclusion LPR events are rare in an asymptomatic population. One or more LPR events should be considered abnormal in patients with LPR symptoms regardless of whether there is a positive DeMeester score.

Oropharyngeal acid reflux and motility abnormalities of the proximal esophagus

“…The motility features of the distal esophagus (DCI, LES resting pressure and 4s-IRP) did not significantly differ in the two groups in this study but this is not really surprising; even in patients with normal distal reflux, the lack of effective proximal reflux clearance might allow a small amount of reflux to flow up from the distal esophagus to the larynx and pharynx, where even a single episode of LPR is considered pathological[25,43]. …”

“…Recently, two new devices that overcome these limitations have been introduced for the detection of LPR: OP pH-metry (Respiratory Technology Corp.)[4-6] and hypopharyngeal multichannel intraluminal impedence (Sandhill Scientific Inc.)[25,26]. We used the OP Dx probe to detect acid reflux in the oropharynx of patients with clinically suspected LPR.…”

Nissen Fundoplication for Laryngopharyngeal Reflux After Patient Selection Using Dual pH, Full Column Impedance Testing

“…Prior normative data were obtained with the proximal pH sensor placed above the UEs in the hypopharynx along with the impedance electrodes that accompany it and 1 more electrode above this (see Figures 1 and 2). 15,16 Normative data would suggest that more than 1 (or some would argue even 1) clear event in the hypopharynx is abnormal. Thus, identifying even 1 hypopharyngeal event in 24 hours may be diagnostic.…”

“…A recent advisory panel report from the American College of Surgeons on the preoperative workup before antireflux surgery supports the use of MII and HRM in patients with LPR symptoms but does not have enough evidence to support the recommendation of Nissen based on the results of these tests alone; further studies are recommended. 15 Outcomes after Nissen fundoplication in patients with LPR selected by dual pH, full column MII (most proximal impedance sensor above the upper esophageal sphincter [UES]) in coordination with HRM have not yet been published. Our study aims to assess if highly selective HRM and MII testing was able to predict LPR-specific symptom resolution after Nissen in a pilot population of patients who presented to a laryngologist specifically for LPR complaints.…”

Reflux and Voice Disorders: Have We Established Causality?

“…It only becomes pathologic if it occurs with adequate frequency or volume to result in symptoms or disease. 3 …”