Intraluminal impedance detects failure of pharyngeal bolus clearance during swallowing: a validation study in adults with dysphagia

Abstract

Multichannel intraluminal impedance (MII) detects bolus flow through a healthy pharynx. The aim of this study was to determine whether the technique detects bolus flow and retention in patients with pharyngeal dysphagia; develop appropriate impedance-based criteria for assessing patients and to provide some preliminary insights into the clinical utility of the technique. Pharyngo-oesophageal pressure and impedance were recorded simultaneously with videofluoroscopy (VF) during swallows in six patients with dysphagia. Agreement, as to the presence or absence of bolus material, between the VF and MII was expressed using the Cohen's Kappa statistic. To test whether the impedance criteria for the detection of bolus passage in dysphagia could be improved, a Kappa statistic was calculated in an iterative process for a range of impedance values (100%-0%) defining bolus head entry and bolus tail clearance from the pharynx. Bolus presence according to the MII criteria previously derived by us in healthy controls demonstrated a modest correlation with VF when applied to this dysphagia population [0.37, 0.5 and 0.58 in the hypopharynx, upper oesophageal sphincter (UOS) and proximal oesophagus respectively]. In the patient population, the optimal impedance criteria were 50% for bolus head entry and 20% for bolus tail clearance. Adopting these criteria demonstrated enhanced agreement between VF and impedance; yielding Kappa coefficients of 0.42 in the hypopharynx, 0.54 in the UOS and 0.62 in the proximal oesophagus. With the adoption of appropriate criteria, pharyngeal impedance measurement can accurately detect bolus passage and failed or impaired clearance during swallowing in patients with dysphagia.

Temporal relationships between wall motion, intraluminal pressure, and flow in the isolated rabbit small intestine

“…To understand how pressure patterns relate to flow, it is necessary to combine several techniques. For example, in the esophagus, manometry has been combined with video fluoroscopy (11,17) and/or intraluminal impedance (28,30,31). These studies have enabled flow to be temporally associated with intraluminal pressures.…”

An experimental method to identify neurogenic and myogenic active mechanical states of intestinal motility

“…Here, manometry has been combined with local measures of impedance during swallowing. Multichannel impedance has been used to measure the clearance of a bolus from the human pharynx and esophagus (Szczesniak et al, 2008, 2009), but can also be used to measure cross sectional area of the gastro-esophageal junction (McMahon et al, 2007; Hoppo et al, 2011), the upper esophageal sphincter (Omari et al, 2012; Regan et al, 2012) and the duodenum (Gregersen et al, 1990). In the present study, a combination manometry/impedance catheter was used to relate local diameter to intraluminal pressure.…”

Inter‐rater reliability and validity of automated impedance manometry analysis and fluoroscopy in dysphagic patients after head and neck cancer radiotherapy

“…Pressure‐flow variables are combined to derive a swallow risk index (SRI), which is a composite score predictive of levels of swallowing dysfunction that predispose to aspiration risk . Furthermore, a novel AIM‐derived measure of postswallow residue, the integral of the ratio of the nadir impedance to postswallow impedance (iZn/Z), has been shown to be a potential non‐radiological predictor of ineffective pharyngeal bolus clearance …”