Physiologic variables for videofluoromanometric assessment of dysphagia: an exploratory study

To assess the physiological variables among Upper Esophageal Sphincter Nadir (UESN), Hypopharyngeal Peak Pressure (HPP) and Pharyngo-Esophageal Pressure Gradient (PEPG) for Videofluoromanometry (VFM).

Exploratory non-randomised prospective study comparing UESN, HPP and PEPG of three cohorts of individuals presumably presenting very distinctive "manometric signatures" based on McConnel's Piston Model of swallowing: 11 non-dysphagic volunteers called the Control Group (CG), 10 dysphagic patients presenting a Myotonic Dystrophy (MD), at various stages of evolution, and 10 patients presenting a CricoPharyngeal Barr (CPB), with no post-swallow pharyngeal residue at a previous Modified Barium Swallow (MBS). VFM tests are performed using solid-state three unidirectional transducers produced by Gaeltec Inc. The simultaneous display storage of the standard fluoroscopic swallow of 10 ml liquid barium with UESN and HPP measurements, continuously recorded on a 3-channel polygraph, is performed using a Kay-Pentax Swallowing Work Station. PEPG calculations are subsequently made.

Significant different HPP and PEPG values were observed between the three cohorts. MD patients presented HPP and PEPG below 100 mmHg while CPB patients presented HPP and PEPG above 200 mmHg. The CG presented HPP and PEPG between 100 and 200 mmHg. UESN values revealed no significant difference between the three cohorts. A reading scale is proposed. The aim of the scale is to make a link between HPP or PEPG values and physiopathological (not diagnostic) conditions. Patients presenting an HPP or PEPG below 100 mmHg indicate a High probability of Pharyngeal Propulsion Impairment while patients presenting an HPP or PEPG above 200 mmHg are more likely to have an Increased Flow Resistance with appropriate Propulsion Response. Pros and cons for calculation of the PEPG, representing a possibly unnecessary step, are discussed.

In our study, the use of HPP or PEPG as physiological variables provides quantitative data that allow VFM to discriminate three very distinctive swallowing conditions. Further studies are needed to assess the HPP and PEPG obtained with other manometic devices within the same specific populations for them to be considered as universal physiological variables. Eventually, further investigations should answer the question as to whether the calculation of the PEPG represents any value in comparison with HPP measurement alone.