Take-home informed consent for intravenous contrast media: do patients learn more?

In 1978, Morrow et al published the results of a simple technique for raising radiation oncology patients' levels of awareness about medical options. They reported that providing written information at least 24 hours in advance was an effective tool for increasing the baseline knowledge in this patient group. However, Morrow's cohort consisted exclusively of cancer patients receiving radiation therapy. The authors of this article are concerned with whether the encouraging results reported by Morrow are reproducible when applied to patients awaiting invasive radiologic procedures.

One hundred sixty consecutive outpatients awaiting contrast were block randomized into one of eight groups based on age, sex, and previous contrast exposure. For each group, half were given their consent form at least 24 hours prior, and the other half at the time of their procedure. All patients were tested at the time of their procedure to evaluate knowledge retention.

Comparison between the two study groups showed no overall statistically significant differences either in knowledge (experimental group 4.7 +/- 1.32 versus 4.38 +/- 1.30 control group) or level of satisfaction. Additionally, individuals experienced with contrast failed to outperform those who had never previously been given contrast. There is no significant difference in the performance between the two sexes regardless of group.

The providing of information 24 to 72 hours in advance of an invasive procedure does not have a beneficial effect over just providing the same information at the time of the study.