Large Buffering Effect of the Duodenal Bulb in Duodenal Switch: a Wireless pH-Metric Study

Abstract

IntroductionBariatric procedures result in massive weight loss, however, not without side effects. Gastric acid is known to cause marginal ulcers, situated in the small bowel just distal to the upper anastomosis. We have used the wireless BRAVO™ system to study the buffering effect of the duodenal bulb in duodenal switch (DS), a procedure in which the gastric sleeve produces a substantial amount of acid.MethodsWe placed a pre- and a postpyloric pH capsule in 15 DS-patients (seven men, 44 years, BMI 33) under endoscopic guidance and verified the correct location by fluoroscopy. Patients were asked to eat and drink at their leisure, and to register their meals for the next 24 h.ResultsAll capsules but one could be successfully placed, without complications. Total registration time was 17.2 (1.3–24) hours prepyloric and 23.1 (1.2–24) hours postpyloric, with a corresponding pH of 2.66 (1.74–5.81) and 5.79 (4.75–7.58), p < 0.01. The difference in pH between the two locations was reduced from 3.55 before meals to 1.82 during meals, p < 0.01. Percentage of time with pH < 4 was 70.0 (19.9–92.0) and 13.0 (0.0–34.6) pre and postpylorically, demonstrating a large buffering effect.ConclusionBy this wireless pH-metric technique, we could demonstrate that the duodenal bulb had a large buffering effect, thus counteracting the large amount of gastric acid passing into the small bowel after duodenal switch. This physiologic effect could explain the low incidence of stomal ulcers.

Marginal Ulcer and Dumping Syndrome in Patients after Duodenal Switch: A Multi-Centered Study

“…In our study, we reported a low incidence of MU, which aligns with the limited available research reporting MU rates ranging from 0.2% to 1.9% in patients following DS [4,[14][15][16][17]. This low occurrence of MU in DS could be attributed to the preservation of the pyloric sphincter, which plays a crucial role in buffering and neutralizing the substantial amount of gastric acid that passes into the small bowel after the procedure [18]. In fact, the alkaline mucus produced by the Brunner's glands in the duodenum plays a role in protecting the ileal mucosa from the high acidity as well as the reduced parietal cell mass from the sleeve gastrectomy [7].…”

Low Risk for Marginal Ulcers in Duodenal Switch and Gastric Bypass in a Well-Defined Cohort of 472 Patients

“…In a previous study with wireless pH-metry, we were able to show that the duodenal bulb has a buffering effect, reducing the time with pH < 4 from 59% in the gastric sleeve to 14% distal to the pylorus. This could theoretically result in lower incidence of MU at the duodeno-ileostomy after DS [25].…”

Adaptations in gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass

“…Below the duodenoileostomy, a more or less neutral environment (5.79 (4.75-7.58)) was observed with an acidic pH < 4 measured during 13.0% (range: 0.0-34.6) of time. These findings suggest that the Brunner's glands located in the duodenal bulb neutralize the acidic content of the gastric sleeve via the secretion of alkaline mucus (38). Whether the buffering effect of the duodenal bulb neutralizes the acidic content in case of a SG remains to be understood.…”

“…Due to the absence of SG studies, clinical studies in patients with duodenal switch provide some first insights. Pre-pyloric pH monitoring during 24 hour indicated the preservation of the acidic gastric environment (pH: 2.66 (Interquartile range of 1.74-5.81)) with an acidic pH < 4 measured during the majority of time (68.7%) (38). Whether these findings can be directly translated to patients with a SG remains unsure due to the difference in surgical procedure.…”