Transperitoneal water transport before, during, and after episodes with infectious peritonitis in patients treated with CAPD

Background: Peritonitis is considered to change peritoneal permeability and influences the long-term change in permeability during peritoneal dialysis. The objective of this study is to evaluate water transport across the peritoneum, expressed as drained ultrafiltration volume, before, during, and after episodes of peritonitis. Methods: A retrospective analysis of data from a group of patients was performed in which drained ultrafiltration volume and glucose concentration in dialysis fluid were recorded for each dwell time every day during time on continuous ambulatory peritoneal dialysis treatment as a part of the clinical routine performed. Days with peritonitis and average of daily measurements 1 month before and after each peritonitis episode were evaluated separately for day and night exchanges. In all, 64 episodes of peritonitis in 30 patients were included in this study. Approximately 15,000 exchanges were recorded. Paired t-est and repeated-measures analysis of variance were performed. Results: Compared with the average for the previous month, there was a significant decrease in ultrafiltration volume for day exchanges occurring 2 days before the appearance of other clinical symptoms of peritonitis (P = 0.029). For night exchanges, the decrease in ultrafiltration volume occurred 24 hours before diagnosis (P < 0.001). Ultrafiltration volume was at its minimum the day of diagnosis for both the day (P < 0.001) and night (P < 0.001) exchanges compared with average volume for the previous month. Ultrafiltration volumes remained low for 2 days after diagnosis during both the day (P = 0.009) and night (P = 0.017) exchanges. Relative to the previous month, glucose concentration on the day of clinical diagnosis of peritonitis did not differ significantly (P = 0.328 and P = 0.963 for day and night shifts, respectively). Overall, no significant changes in ultrafiltration volumes or glucose concentrations from the month before to the month after the peritonitis episode were found (P = 0.99 and P = 0.27 for measurements during the day, respectively). Conclusion: Osmotic forced ultrafiltration decreased during infectious peritonitis, most significantly for a long dwell time, consistent with an increase in both functional peritoneal surface area and hydraulic conductivity. This finding appeared 2 days before other clinical symptoms and remained significantly low 2 days after diagnosis.