Review to Contrast Material Reactions

Photo: Computer tomograph

Physician often use contrast agent
in CT scans; © NCI Visuals Online

"While adverse reactions to iodinated contrast media are rare, they are encountered regularly by all physicians who administer contrast material to patients and some of these reactions will require treatment," said Richard Cohan, MD, lead author of the study. "We reviewed our experience to determine how often we encountered these reactions in our practice and how often the reactions required treatment", said Cohan.

The study consisted of 84,928 IV injections of nonionic iodinated contrast media in adults. In this group, there were 545 (0.6 percent) patients who had allergic-like reactions, with 221 receiving treatment. The most commonly administered medications were diphenhydramine to 145 (27 percent) reacting patients, corticosteroids to 17 patients, albuterol to 16 patients, ephinephine to 15 patients, and nitroglycerin to eight patients.

According to the study, 99 percent of the allergic-like reactions resolved completely within 24 hours. This included all 418 patients who had mild reactions, all 116 patients who had moderate reactions, and nine of the 11 patients who had severe reactions.

"In our study, we found a number of instances in which non-recommended treatment was provided”, said Cohan. “These cases included the administration of oxygen by nasal cannula (rather than mask) and at lower than recommended doses, over-utilization of diphenhydramine and the administration of higher than recommended doses of epinephrine, as well as occasional confusion about which concentrations of epinephrine should be injected in which manner (subcutaneously or intravenously).

"We hope that after reading our study, radiologists, nurses, and technologists will agree that they must review the algorithms for treating contrast reactions on a regular basis (particularly issues related to diphenhydramine, oxygen, and epinephrine administration)," said Cohan.

MEDICA.de; Source: American Roentgen Ray Society