Compliance curves during peritoneal dialysate infusion are like a distensible tube and are similar at multiple UGI sites.

OBJECTIVE: Disorders from increased intraabdominal pressure (IAP) result from filling the abdominal cavity beyond its capacity. The aims of this study were 1) to examine pressure:volume curves as fluid is infused into the intraabdominal cavity, and 2) to ascertain the best UGI site for indirect IAP measurements.
METHODS: Chronic ambulatory peritoneal dialysis patients were studied (n = 4) supine. On day 1, manometry catheters measured IAP indirectly (intragastric and intrarectal) and intraesophageal (three sites) pressure. On day 2, antral-duodenal-jejunal manometry was performed to compare indirectly measured IAP at multiple sites. On both days, dialysate was infused at 200 ml/min until IAP was > or = 15 mm Hg or patient experienced severe discomfort.
RESULTS: Filling had three phases: 1) an initial small increase in IAP as infusion began; 2) minimal further increase in IAP during infusion to about 3 L concurrent with a progressive increase in abdominal girth and mild abdominal discomfort; and 3) a linear increase in IAP with infusion > 3 L concurrent with intense abdominal discomfort and little increase in abdominal girth. During study day 2, intragastric, intraduodenal, and intrajejunal pressures were usually similar.
CONCLUSIONS: The compliance curve of the abdomen with filling is similar to that of the bladder and large veins. Compliance curves with provocative meals may be useful in evaluating postprandial abdominal pain, dyspepsia, and bloating.