Objective: To determine the rate of radioactive chloride absorption at various times after surgery in patients with a continent ileocaecal reservoir (Mainz pouch I).
Patients and methods: The study was conducted on 20 patients (15 males and five females, mean age 47 years, range 15-72) who had undergone a Mainz pouch I urinary diversion. The patients were divided into three groups according to the duration of the post-operative follow-up, i.e. group 1 for < 6 months (n = 7), group 2 for 6-12 months (n = 8) and group 3 for > 12 months (n = 5). Radioactive 38Cl (20 MBq) was instilled into the pouch and the radioactivity determined in the blood, pouch and body interstitium every 20 min for 3 h. Samples for arterial blood-gas and acid-base profiles were obtained before and after instillation.
Results: In patients in group 1, 93% of the instilled chloride was absorbed into the circulation, while 51% was absorbed by patients in group 3. The acid-base profile showed no significant changes before and after chloride instillation.
Conclusion: The absorption of chloride declines markedly with time after surgery in patients with a Mainz pouch I ileocaecal reservoir.