What does peritoneal thickness in peritoneal dialysis patients tell us?

Loss of peritoneal function is a major factor leading to failure of treatment in peritoneal dialysis (PD). Although the precise biologic mechanisms responsible for these changes have not been defined, the general assumption is that alterations in peritoneal function are related to structural changes in the peritoneal membrane. The aim of the present study was to uncover the relationship between functional parameters of peritoneum and peritoneal thickness as measured by ultrasonography. We studied 43 prevalent patients who had been on PD for at least 12 months in the Ege University PD unit. We recorded body weight, height, age, sex, PD duration, episodes of peritonitis, and results of peritoneal equilibration tests. Parietal peritoneal thickness was measured from four abdominal quadrants at the mid-clavicular line. The peritoneal thickness measurement was determined as the mean of the four separate measurements. (In some cases, the measurement at one of the lower quadrants was excluded from the calculation if the peritoneal catheter was present near the area probed.) Mean peritoneal thickness in the patients was 446 +/- 164 microm (range: 250-930 microm), which was significantly correlated with mean body weight (r = 0.31, p < 0.05), height (r = 0.31, p < 0.05), end-to-initial ratio of dialysate glucose (r = -0.44, p < 0. 01), dialysate-to-plasma creatinine (r = 0.51, p < 0.01), and PD duration (r = 0.48, p < 0.01). Peritoneal thickness was positively correlated with time on dialysis, being a median of 370 microm [interquartile range (IQR): 283-400 microm] in patients who had been on PD for less than 24 months up and 660 microm (IQR: 483-733 microm) in patients who had undergone PD for more than 6 years. Ultrasound examination is a simple and noninvasive method of measuring peritoneal thickness in PD patients. It may be useful in the study of peritoneal structure and function. Sequential measurements over time may be useful for early diagnosis of encapsulating peritoneal sclerosis.