Value of endoscopic grading of gastroesophageal flap valve in gastroesophageal reflux disease.

OBJECTIVE: To investigate the significance of endoscopic grading (Hill's classification) of gastroesophageal flap valve (GEFV) in the examination of patients with gastroesophageal reflux disease (GERD). METHODS: One hundred and sixty-two patients undergoing gastroscopy in the Department of Gastroenterology, Xingyi People's Hospital between Apr. 2022 and Sept. 2022 were selected by convenient sampling, and data such as GEFV grade, and findings of esophageal high-resolution manometry (HRM) and esophageal 24-h pH/impedance reflux monitoring, and Los Angeles (LA) classification of reflux esophagitis (RE) were collected and compared. RESULTS: Statistically significant differences in age (F = 9.711, P < 0.001) and hiatal hernia (χ = 35.729, P < 0.001) were observed in patients with different GEFV grades. The resting LES pressures were 12.12 ± 2.79, 10.73 ± 2.68, 9.70 ± 2.29, and 8.20 ± 2.77 mmHg (F = 4.571, P < 0.001) and LES lengths were 3.30 ± 0.70, 3.16 ± 0.68, 2.35 ± 0.83, and 2.45 ± 0.62 (F = 3.789, P = 0.011), respectively, in patients with GEFV grades I-IV. DeMeester score (Z = 5.452, P < 0.001), AET4 (Z = 5.614, P < 0.001), acid reflux score (upright) (Z = 7.452, P < 0.001), weak acid reflux score (upright) (Z = 3.121, P = 0.038), liquid reflux score (upright) (Z = 3.321, P = 0.031), acid reflux score (supine) (Z = 6.462, P < 0.001), mixed reflux score (supine) (Z = 3.324, P = 0.031), gas reflux score (supine) (Z = 3.521, P = 0.024) were different in patients with different GEFV grades, with statistically significant differences. Pearson correlation analysis revealed a positive correlation between RE grade and LA classification of GERD (r = 0.662, P < 0.001), and the severity of RE increased gradually with the increase of the Hill grades of GEFV. CONCLUSION: The Hill grade of GEFV is related to age, hiatal hernia, LES pressure, and the consequent development and severity of acid reflux and RE. Evaluation of esophageal motility and reflux based on the Hill grade of GEFV is of significance for the diagnosis and treatment of GERD.

Microscopic Mechanism of CO2 Displacement Oil in Different Pore Throat Radius Segments of Tight Sandstone Reservoirs.

The micropore structure of tight sandstone affects the efficiency of CO2 displacement of crude oil. As the pressure changes, the oil displacement efficiency (E d) in segments with different pore radii changes, and the asphaltene precipitation in the pores causes alterations in the pore structure and wettability, which constrain E d. Ten samples of tight sandstone from the Yanchang Formation in the Ordos Basin were selected for this study. A variety of methods, including X-ray diffraction (XRD), casting thin sections (CTS), scanning electron microscopy (SEM), high-pressure mercury intrusion (HPMI), CT scanning, and nuclear magnetic resonance (NMR) combined with CO2 displacement, were used to study the efficiency of crude oil utilization and the amount of asphaltene deposited at different pore-throat radii, and then the impacts of pressure, pore structure, and wettability changes on E d were discussed. The findings indicate that samples have three types: macropore-fine throats (MF), medium pore-tiny throats (MT), and small pore-microthroats (SM). The MT exhibits a favorable configuration. The pore-throat radius of each sample can be divided into two segments, namely, large pore segments (PL) and small pore segments (PS), and the PL has a significant E d. The E d of the MF-type PS is constrained by pressure. The E d of PL is significantly affected by the pressure sensitivity for the MT, while the E d of PL for the SM structure is more affected by pressure. Changes in wettability and the precipitation of asphaltene are the results of the reaction between crude oil and CO2. In the MF, asphaltene precipitates from the PL, while in the MT and SM, asphaltene precipitates both from the PL and PS. The amount of asphaltene precipitation strongly affects the E d in PS. The oil wettability increases more obviously with better pore-throat configurations. This study offers a reference and foundational understanding for evaluating CO2 displacement in tight sandstone reservoirs.