Esophageal function testing: role of combined multichannel intraluminal impedance and manometry.

Combined multichannel intraluminal impedance and manometry (MII-EM) is a relatively new technique that allows simultaneous measurement of intraesophageal pressures and bolus transit. Combined MII-EM has the ability to identify what percentage of manometric normal/peristaltic, ineffective, and simultaneous swallows have complete or incomplete bolus transit. Predictors of normal bolus transit in patients with ineffective esophageal motility are the distal esophageal amplitude, the number of sites with low amplitudes, and the overall number of manometric ineffective contractions. Outcome studies are necessary to evaluate whether combined MII-EM is superior to traditional manometry in evaluating patients with nonobstructive dysphagia and in identifying patients at risk for developing dysphagia after antireflux surgery.