Yoshiya Nakagawa

Relationship between postprandial esophageal acid exposure and meal volume and fat content

The effect of meal volume and fat content on gastroesophageal reflux was investigated in 20 asymptomatic healthy subjects. In each subject, intraesophageal pH monitoring was performed during a 3-hr postprandial period (PP) in the same position (supine or upright) on two successive days. On day 1, 500-ml low- and high-fat meals were ingested and, on day 2, an 800-ml low-fat meal was ingested. The acid exposure time was assessed as the percentage of time with a pH<4.0. The acid exposure time in subjects in the upright position was significantly longer in the 800-ml group than in the 500-ml group for the entire PP (2.7 ± 1.5%; mean ±se, 0.7 ± 0.4%;P<0.05). Of subjects in the supine position, the high-fat group showed significantly longer acid exposure time than the low-fat group both for the entire PP (7.6 ± 3.0%, 0.7 ± 0.5%; p<0.05) and for the second hour (P<0.05). We have demonstrated that differences in the meal volume and fat content influence gastroesophageal reflux in healthy asymptomatic subjects and that this influence varies with the position.

Effect of body position on lower esophageal sphincter pressure.

Abstract: This study examined the effect of body position on lower esophageal sphincter (LES) pressure. In 36 healthy subjects and 31 patients with reflux esophagitis, LES and intragastric pressures were measured with subjects in the supine and sitting positions by the intraluminal microtransducer method. LES pressure was significantly lower in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis. Intragastric pressure was significantly higher in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis, but this increase was less marked than the decrease in LES pressure in the sitting position. The overlap of LES pressure values between healthy subjects and patients with reflux esophagitis was lower in the sitting position than in the supine position. We conclude that the measurement of LES pressure in the sitting position reflects LES function more accurately.

Effects of body position and liquid meal ingestion on esophageal acid exposure time in healthy subjects

Abstract: We investigated the effect of body position and ingestion of a test liquid meal on esophageal acid exposure time in 20 asymptomatic healthy subjects. Intraesophageal pH monitoring was performed for 1 h before meals and 3 h postprandially with the subject in the supine (n = 10) or sitting position (n = 10). The test meal had a total volume of 800 ml and an energy content of 500 kcal. Esophageal acid exposure time was defined as the percentage of time at pH < 4.0. There was no difference in preprandial or postprandial esophageal acid exposure time between the supine and sitting positions. Esophageal acid exposure time for the 3-h postprandial period was significantly greater than that for the preprandial period in both the supine and the sitting positions. The difference in body position did not influence preprandial or postprandial esophageal acid exposure time, but ingestion of the liquid meal significantly increased the esophageal acid exposure time in both the supine and sitting positions in asymptomatic healthy subjects.

Effects of transjugular intrahepatic portosystemic shunt (TIPS) on esophageal motor function and gastroesophageal reflux

Abstract: The effects of transjugular intrahepatic portosystemic shunt (TIPS) placement on esophageal motor function and gastroesophageal reflux were investigated in patients with esophageal varices. In six men with esophageal varices, esophageal manometry and upper gastrointestinal endoscopy were performed before and 15–20 days after TIPS placement. Intraesophageal pH monitoring was performed in the four patients with severe esophageal varices (defined as the largest sized varices) following TIPS placement. Findings were compared with those in six healthy men (controls) who underwent esophageal manometry and intraesophageal pH monitoring. The esophageal varices resolved or were reduced after TIPS placement. Resting lower esophageal sphincter (LES) pressures were similar in the study group before and after TIPS placement and in the control subjects. The incidence and progression of esophageal contractions were similar in the study group before and after TIPS placement and in the control subjects. At 3 cm above the LES, the amplitude of esophageal contraction after TIPS placement was significantly higher than that before TIPS placement. At 3 and 8 cm above the LES, the amplitude of esophageal contraction in the control subjects was significantly higher than that in the study group before and after TIPS placement. Esophageal acid exposure time after TIPS placement was similar to that in the controls. TIPS placement is a useful treatment that improves esophageal motor function without the occurrence of pathologic gastroesophageal reflux.