It was recently shown that GERD patients have lower impedance baseline values than healthy controls and, that the esophageal acid exposure time correlates with impedance baseline levels.
Dr Mentore Ribolsi and colleagues from Italy explored the sensitivity of impedance baseline measurements in NERD patients, responders and non-responders to PPIs, when compared with pH-impedance variables.
In addition, the team evaluated whether this variable could represent a marker of GERD symptoms.
Reproducibility and inter-observer agreement of impedance baseline measurement were also assessed.
The researchers analyzed pH-impedance tracings from 44 NERD responders, and 22 non-responders.
|38% showed impedance baseline values lower than controls|
|Scandanavian Journal of Gastroenterology|
The research team reported that 10 healthy volunteers underwent the same protocol.
Impedance baseline values were measured at the distal and proximal esophagus.
Impedance baseline was also analyzed in a subgroup of patients, and in controls with 2 methods, and by 2 blinded operators.
Mean impedance baseline values at the distal esophagus were significantly lower in NERD patients than in controls.
Impedance baseline values did not differ between responders and non-responders.
Of the 8 responders with negative esophageal acid exposure time and symptom association probability, 38% showed impedance baseline values lower than controls.
The team found that impedance baseline values in responders with positive and negative symptom association probability were similar.
The research team found no differences between the impedance baseline values measured with the 2 methods, and the inter-observer agreement was good.
Dr Ribolsi's team concludes, "Impedance baseline is a promising and easy to calculate pH-impedance variables, and appears to increase the sensitivity of pH-impedance monitoring."
"Impedance baseline values cannot predict PPI response and are not associated with reflux perception in NERD patients."