Impedance manometry with viscous test solution increases detection of esophageal function defects compared to liquid swallows

Objective. Multichannel intraluminal impedance and manometry (MII-EM) is performed using ten 5-ml swallows each of a liquid and a viscous solution. However, the manometric diagnosis is based solely on results from the 10 liquid swallows. The aim of this study was to compare esophageal function evaluated with 10 liquid versus 10 viscous swallows using combined MII-EM in patients with various symptoms. Material and methods. Consecutive studies performed in 300 patients (211F, mean age 54.5 years) were analyzed. The manometric diagnoses were separated into normal and abnormal manometry. MII findings included the number of complete and incomplete transits and total bolus transit time. Results. Manometric diagnosis for liquid and viscous solutions was consistent in 231 (77%) and inconsistent in 69 (23%) patients (p=0.0001). Overall, the number of manometric abnormalities detected with the viscous solution (n=91, 30.3%) was significantly higher (p=0.03) than that detected with the liquid solution (n=60, 20%). Impedance diagnosis for the viscous and liquid solutions was consistent in 238 (79.3%) patients and inconsistent in 62 (20.7%) patients (p=0.0001). Among those 62 patients, 36 (58.1%) had complete bolus transit with the liquid solution and incomplete bolus transit with the viscous solution, and 26 (41.9%) had incomplete bolus transit with the liquid solution and complete transit with the viscous solution (p=0.46). Overall, there was no significant difference between the number of bolus transit abnormalities for the liquid (n=75, 25%) and viscous solutions (n=85, 28.3%, p=0.47). Conclusions. Our results indicate that a viscous solution detects significantly more manometric abnormalities than a liquid solution. Impedance diagnosis has greater similarity for both the liquid and viscous solutions.