Carbon dioxide as a lighter-than-urine contrast medium for percutaneous nephrostomy.

Carbon dioxide was used either alone or in combination with standard triiodinated contrast media in 32 patients who underwent percutaneous nephrostomy. Carbon dioxide was used to opacify the posterior calyces, which are the uppermost structures in the kidney of the prone or prone-oblique patient. Carbon dioxide is usually injected in small amounts (20-40 cm3), although clinical and laboratory data indicate that it can be used as the only medium in large amounts with complete safety. There were no complications.