Contrast medium-induced pulmonary edema is aggravated by silicone contamination in rats

To examine the effect of silicone contamination, which occurs in clinical settings during vial preparation with disposable syringes, on contrast medium-induced pulmonary edema in rats.

Ioxaglate, ioversol, and iohexol, silicone-containing physiologic saline solutions, and three silicone-containing contrast media were separately, intravenously injected at 1.5 mL/min in rats. Pulmonary edema was evaluated as changes in the relative lung weight and in the water, sodium, and potassium contents of the lung.

Intravenous injection of ioxaglate induced marked pulmonary edema, even with a dose of only 4 g of iodine per kilogram of body weight. In contrast, ioversol and iohexol induced significant pulmonary edema only after the injection of large doses (6 g of iodine per kilogram; P < .05). The injection of 4 microL/mL silicone-containing physiologic saline at a dose of 18.75 mL/kg also produced marked pulmonary edema, whereas doses of 6.25 and 12.5 mL/kg showed no significant influence. The addition of an ineffective dose (12.5 mL of physiologic saline per kilogram of body weight) of silicone in contrast medium substantially aggravated the pulmonary edema induced by the contrast medium alone; this phenomenon was also confirmed with morphologic observation.

Ionic contrast media are more toxic to the endothelial cells than are nonionic contrast media. Silicone contamination might be one of the causes of pulmonary edema after intravenous injection. However, caution must be exercised in extrapolating these results to humans.