Normal values for manometry performed with swallows of viscous test material

Objective. Esophageal function testing with combined multichannel intraluminal impedance and manometry (MII-EM) is performed using ten 5-ml liquid and viscous swallows. Diagnosis of bolus transit abnormalities identified by impedance is based on both liquid and viscous swallows. Manometric diagnosis is based solely on liquid swallows. The aim of this study was to establish the normal values for manometry performed with a viscous bolus. Material and methods. MII-EM studies performed in 80 healthy volunteers were analyzed. The analyzed manometric parameters included contraction amplitude and duration, distal onset velocity and lower esophageal sphincter (LES) residual pressure. Results. Mean distal esophageal amplitude (DEA) (mmHg) for liquid swallows was 104 (±44) and for viscous swallows 102 (±51). Viscous versus liquid swallows were characterized by higher contraction amplitudes at 10 cm above the LES, slower distal onset velocities and higher LES residual pressures. Duration of contractions was similar between liquid and viscous swallows. Upper normal limits for viscous swallows were: 204 mmHg for DEA (mean±2 SDs); 6 ineffective and 1 simultaneous swallows and 11.7 mmHg for LES residual pressure (95th percentile). Conclusions. Based on our results, the following values should be considered normal for manometry performed with viscous swallows: ≤60% ineffective contractions, ≤10% simultaneous contractions and DEA <204 mmHg, LES residual pressure ≤11.7 mmHg.