The effect of informed consent on the level of anxiety in patients given i.v. contrast material.

OBJECTIVE

A common reason given for not obtaining informed consent before the use of IV contrast material is that the anxiety created by informing patients of potential reactions will increase the possibility of their occurring. However, the idea that this is possible is debatable, and no study of this subject has used a standardized anxiety index. Accordingly, using the State-Trait Anxiety Inventory, we assessed the anxiety level among patients about to have an IV contrast procedure and measured the effect of informing them of the risks associated with the use of contrast material.

SUBJECTS AND METHODS

Approximately 2050 adult outpatients at three separate medical centers were solicited for participation in this study. Each of the 1251 patients who volunteered to participate was placed into one of six groups. The majority were patients who were awaiting the injection of either ionic or nonionic contrast material and who were or were not informed of the risks associated with the use of IV contrast material. The last two groups were generally healthy outpatients reporting for routine X-rays who were not awaiting IV contrast administration but who were informed of the risks associated with the use of ionic and nonionic contrast material. Each patient informed of the risks was asked to read a standardized consent form, and all patients completed a standardized anxiety index.

RESULTS

Patients who were informed of the risks associated with IV contrast material did not have measurably increased anxiety, and they did not have an increased prevalence of adverse reactions. Indeed, the only patients who had statistically significant increased anxiety compared with the other groups were among those awaiting the injection of ionic contrast material who were not informed of the risks (p = .04). The majority (51-78%) of patients in all six groups had measurable elevated anxiety scores.

CONCLUSION

We conclude that it is not justified to fail to obtain informed consent in order to avoid anxiety-induced adverse reactions to IV contrast material. The majority of patients awaiting injection of IV contrast material have measurable increased anxiety levels regardless of whether they are informed of its risks.