Gastric intramucosal acidosis in patients with chronic kidney failure

Patients with chronic kidney failure have an increased incidence of gastrointestinal complications, particularly bleeding from the stomach. Diminished mucosal blood flow is thought to be an important etiologic factor for such bleeding.

Eleven patients with kidney failure on maintenance dialysis underwent placement of a gastric tonometer for the determination of gastric intramucosal pH (pHi) before and during dialysis. The arterial pH (pHa), calculated pHi, and pHa-pHi differences were compared with the results in a control group of seven normal volunteers.

The patients with chronic kidney failure had a mean (+/- SD) pHa (7.36 +/- 0.04) similar to that found in seven control subjects (7.37 +/- 0.04). However, the gastric mucosal pH in the patients on dialysis (7.20 +/- 0.17) was lower than in the seven control subjects (7.38 +/- 0.06) (p < 0.01). A gastric mucosal pH thought to be predictive of either bleeding from stress ulceration (pHi < 7.32) or mucosal ischemia (pHi-pHa difference > 0.13) was found in nine (82%) of the patients with kidney failure and in only one (14%) of the control subjects (p < 0.001).

This new preliminary finding suggests that the high incidence of gastric bleeding in chronic kidney failure may be related to mucosal ischemia.