To establish the normal values of water-perfused high resolution esophageal manometry (HREM)(GAP-36A) at resting period, water swallowing, semisolid swallowing and solid swallowing in Chinese population.

From September 1, 2019 to June 30, 2020, 91 healthy volunteers receiving water-perfused HREM (GAP-36A) at resting period, water swallowing, semisolid swallowing and solid swallowing were selected from 9 hospitals (Union Hospital, Tongji Medical College, Huazhong University of Science and Technology; the First Affiliated Hospital of Dalian Medical University; the Second Hospital of Hebei Medical University; the Second Affiliated Hospital, Naval Medical University; the First Affiliated Hospital, Sun Yat-sen University; the First Affiliated Hospital, University of Science and Technology of China; Aviation General Hospital of China Medical University; the Affiliated Hospital of Medical School of Nanjing University and the First People′s Hospital of Yichang). Parameters included the position of the upper and lower edges of the upper esophageal sphincter (UES) and lower esophageal sphincter (LES), the length of the LES and UES, the position of the pressure inversion point (PIP), the resting pressure of UES and LES and swallow-related parameters such as the distal contraction integral (DCI), 4 s integrated relaxation pressure (IRP), distal latency (DL) and UES residual pressure. One-way analysis of variance, post-hoc test and sum rank test were used for statistical analysis.

A total of 87 healthy volunteers were enrolled, including 40 males and 47 females, aged (38.5±14.2) years old (ranged from 19 to 65 years old). The position of the upper and lower edges of the LES was (42.7±2.8) and (45.6±2.8) cm, respectively, the length of the LES was (2.9±0.4) cm, and the position of PIP was (43.3±2.8) cm. The position of the upper and lower edges of the UES was (18.1±3.0) and (22.6±2.0) cm, respectively, and the length of the UES was (4.8±1.0) cm. The resting pressure of LES and UES was (17.4±10.7) and (84.1±61.1) mmHg (1 mmHg=0.133 kPa), respectively. The DCI value at solid swallowing was higher than those at water swallowing and semisolid swallowing ((2 512.4±1 448.0) mmHg·s·cm vs. (2 183.2±1 441.2) and (2 150.8±1 244.8) mmHg·s·cm), and the differences were statistically significant (t=-4.30 and -3.74, both P<0.001). The values of 4 s IRP at semisolid swallowing and solid swallowing were lower than that at water swallowing ((4.6±4.1) and (4.9±3.9) mmHg vs. (5.4±3.9) mmHg), and the differences were statistically significant (t=3.38 and 2.09, P=0.001 and 0.037). The DL at water swallowing was shorter than those at semisolid swallowing and solid swallowing ((8.5±1.8) s vs. (9.8±2.2) and (10.6±2.8) s), and the DL at semisolid swallowing was shorter than that at solid swallowing, and the differences were statistically significant (t=-10.21, -13.91 and -4.68, all P<0.001). The UES residual pressure at water swallowing was higher than those at semisolid swallowing and solid swallowing (9.5 mmHg, 6.5 to 12.3 mmHg vs. 8.0 mmHg, 4.5 to 11.7 mmHg and 5.5 mmHg, 2.0 to 9.3 mmHg), and the UES residual pressure at semisolid swallowing was higher than that at solid swallowing, and the differences were statistically significant (t=3.48, 10.30 and 6.35, all P<0.001).

The normal values of water-perfused HREM (GAP-36A) in Chinese population at resting period, water swallowing, semisolid swallowing and solid swallowing can provide a reference basis for clinical diagnosis and treatment for patients receiving water-perfused HREM examination.

High resolution esophageal manometry; Water-perfused; Normal values; Multicenter study