[Effects of the intravenous injection of an ionic contrast medium on the circulating plasma volume: an assessment with plasma colloid oncotic pressure].
We investigated effects of intravenous injection of ionic contrast medium (ICM) on circulating plasma volume (CPV) by measurements of changes in plasma colloid oncotic pressure (COP).


METHODS
ICM (60% meglumine iothalamate 30 ml) was injected intravenously as a bolus into 7 healthy male volunteers. The venous blood samples were drawn before, and 1, 2, 3, 5 and 10 minutes after the injection. Relatively massive doses of the ICM (150-180 ml) were infused intravenously into 6 male cardiac patients with normal cardiac and renal function during ECG gated cardiac X-ray computed tomography. The blood samples were drawn before, soon after and an hour after the infusion. The plasma COP values of the blood samples were measured with a needle-type osmometer and the sequences of CPV were estimated from the changes of COP values.


RESULTS
The bolus injection of the ICM increased the CPV by 10%, 8-9 ml of the CPV per 1 ml of the ICM, and the increase continued during the study (at least for 10 minutes). The massive infusion of the ICM resulted in about 20% increase of the CVP soon after the infusion, and then induced a diuletic effect. The CVP returned to the basal level in one hour, but some patients became rather dehydrated.


CONCLUSIONS
These findings suggested that an intravenous injection of ICM produced considerable expansion of CPV and subsequent dehydration. Careful considerations would be necessary when patients with impaired cardiac or renal function are treated with intravenous ICM during X-ray computed tomography or digital subtraction angiography.
D000328:Adult; D003102:Colloids; D003287:Contrast Media / Q000008:administration & dosage / Q000009:adverse effects*; D006400:Hematocrit; D006801:Humans; D007275:Injections, Intravenous / Q000379:methods; D007482:Iothalamate Meglumine / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009997:Osmotic Pressure; D010953:Plasma Volume / Q000187:drug effects*
D003102:Colloids; D003287:Contrast Media; D007482:Iothalamate Meglumine