IONIC VERSUS NONIONIC CONTRAST-MEDIA - A PROSPECTIVE-STUDY OF THE EFFECT OF RAPID BOLUS INJECTION ON NAUSEA AND ANAPHYLACTOID REACTIONS

Purpose: The purpose of our study was to evaluate the effect of bolus infusion of contrast medium (ionic versus nonionic) on the incidence o f nausea and anaphylactoid reactions. Method: We prospectively studied 1,827 patients who had bolus enhanced body CT scans and divided them into four groups: 725 patients received higher osmolality contrast med ium (HOCM) at the slower bolus rate of 1-2.5 mils (SLOW-HOCM group); 6 50 patients were in the FAST-HOCM group and received the same ionic co ntrast medium at 4-5 ml/s; 250 patients received lower osmolality cont rast medium (LOCM) at 1-2.5 ml/s, forming the SLOW-LOCM group; and 202 patients in the FAST-LOCM group got the same nonionic agent at 4-5 ml /s. Results: We found no significant difference in the rate of nausea among the first three groups: SLOW-HOCM (3.9%), FAST-HOCM (4.9%), and SLOW-LOCM (3.2%). A statistically significant lower incidence of nause a (0.5%) was found in the FAST-LOCM group. Anaphylactoid reactions wer e significantly more common in both groups who received HOCM (8.3 and 9.1%) compared with the groups who received LOCM (2.0 and 2.5%). Concl usion: The bolus injection of warmed ionic contrast medium at a rate o f 1-2.5 ml/s causes no significant increase in nausea compared with si milar infusion rates of nonionic agents. For CT protocols that require infusion rates of 4-5 ml/s, the use of a nonionic agent is associated with a significantly reduced prevalence of nausea. The prevalence of anaphylactoid reactions is not affected by the rate of injection.