American Journal of Roentgenology, Vol 162, 531-535, Copyright © 1994 by American Roentgen Ray Society
The effect of informed consent on the level of anxiety in patients given i.v. contrast material
KD Hopper, PS Houts, TR TenHave, YL Matthews, E Colon, DB Haseman and J Hartzel
Department of Radiology, Pennsylvania State University, Hershey 17033.
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.