SHORT-TERM EFFECTS OF SELECTIVE RENAL ARTERIAL CARBON-DIOXIDE ADMINISTRATION ON THE DOG KIDNEY

PURPOSE: The authors examined the nephrotoxicity of carbon dioxide inj ected directly into the renal arteries as an arterial contrast agent. MATERIALS AND METHODS: Fourteen anesthetized dogs received selective r enal infusions of CO2 ranging from a normal dose of 7 cm3/kg to high d oses of 11-54 cm3/kg. Two dogs received conventional iodinated contras t media. The effects on renal function and histologic appearance were evaluated by means of radionuclide studies (iodine-131 iodohippurate s odium and technetium-99m dimercaptosuccinate) and histopathologic exam ination (light, transmission, and scanning electron microscopy). RESUL TS: Although there was a mean decrease in renal blood flow of 11.86% ( standard error [SE], 7.1) immediately after the injection of CO2, flow had returned to baseline (0.17%; SE, 5.27) after 24 hours. Although t he sample size was small, there was no dose-dependent effect of CO2 on renal function and histologic appearance. Mild histologic changes and one case of moderate acute tubular necrosis were seen only in cases i n which the kidney was positioned vertically rather than laterally. CO NCLUSION: Although formal studies in patients are required, the result s of this investigation suggest that CO2 may be a safe contrast agent and less nephrotoxic than existing contrast agents, providing care is taken to ensure that CO2 is not trapped in a vertically positioned kid ney, as might occur in renal transplant recipients.