Pneumoperitoneum aggravates renal function in cases of decompensated but not compensated experimental congestive heart failure: role of nitric oxide.

Purpose: Congestive heart failure is associated with impaired renal function. Previously we noted that increased intra-abdominal pressure (pneumoperitoneum) in normal rats induced renal dysfunction. In this study we investigated the renal effects of pneumoperitoneum in rats with compensated (urinary Na(+) excretion greater than 1,200 μEq per 24 hours) and decompensated (urinary Na(+) excretion less than 200 μEq per 24 hours) congestive heart failure, and the possible involvement of nitric oxide in these effects.

Materials And Methods: After a baseline period rats with congestive heart failure induced by aorto-caval fistula and sham operated controls underwent consecutive intra-abdominal pressures of 7, 10 or 14 mm Hg for 45 minutes each. Urinary flow, urinary Na(+) excretion, glomerular filtration rate, renal plasma flow and urinary nitric oxide metabolites were determined.

Results: There were no changes in urinary flow, urinary Na(+) excretion, glomerular filtration rate or renal plasma flow during 7 mm Hg insufflation in controls. However, significant decreases in these parameters were observed during 10 and 14 mm Hg in correlation with intra-abdominal pressure. Baseline renal function and hemodynamics were lower in rats with congestive heart failure in correlation with disease severity. Rats with decompensated congestive heart failure that underwent 10 and 14 mm Hg showed aggravated decreases in urinary flow, urinary Na(+) excretion, glomerular filtration rate and renal plasma flow. In contrast, no adverse renal effects were observed in rats with compensated congestive heart failure under identical intra-abdominal pressure conditions. Despite unaltered baseline urinary nitric oxide metabolites in the 2 congestive heart failure subgroups, the decompensated group showed decreased urinary nitric oxide metabolites after 14 mm Hg. Finally, rats with compensated congestive heart failure pretreated with the nitric oxide synthase inhibitor L-NAME showed worse renal function in response to pneumoperitoneum.

Conclusions: Decompensated congestive heart failure renders rats susceptible to the adverse renal effects of pneumoperitoneum, a phenomenon that may involve alterations in the renal nitric oxide system.