Normative Values and Factors Affecting Water-Perfused Esophageal High-Resolution Impedance Manometry for a Chinese Population

BackgroundCombined esophageal high-resolution impedance manometry (HRIM) measures multiple pressures and bolus transit simultaneously, facilitating detailed assessment of esophageal motility. Currently, normative values for water-perfused HRIM systems for Chinese populations are lacking. MethodsHealthy volunteers were enrolled for comprehensive anthropometric measures, blood biochemistry tests, and an HRIM study using 22 water-perfused pressure sensors and 12 impedance channels. Ten 5-mL liquid swallows of saline at 30-second intervals were conducted. The following parameters were calculated: distal contractile integral (DCI), distal latency (DL), lower esophageal sphincter (LES) basal pressure, 4-second integrated relaxation pressure (IRP-4s), and complete bolus transit percentage. Normal values were established based on the 5th and 95th percentiles. Key ResultsAll 66 participants (34 male, 32 female, aged 21-64years) completed the study and tolerated the HRIM procedure well. The upper normal limit (95th percentile) of IRP-4second was 20mmHg. The 5th-95th percentile range for DCI, DL, and complete bolus transit was 99-2186mmHg.s.cm, 6.2-11.3second, and 50%-100%, respectively. Age was negatively correlated with DL. Females had significantly higher upper limits for IRP-4s and median DCI than males. Multivariate analyses confirmed that IRP-4s was higher in females, and that higher body mass index and waist circumference were associated with reduced DL and better bolus transit, respectively. Conclusions and InferencesWe established normative values for the water-perfused HRIM system for a Chinese population. Gender and anthropometric factors may affect various major HRIM parameters and should be taken into account when interpreting HRIM results in clinical practice.