Effect of informed consent for intravascular contrast material on the level of anxiety: how much information should be given?

Abstract

Purpose: To compare the effect of two different informed consent forms on patients' anxiety level prior to intravenous contrast material (IVCM) injection.

Material and methods: Two different informed consent forms were randomly given to 265 consecutive patients referred for either intravenous pyelography or computed tomography requiring IVCM injections. Form 1 had brief information, including only the common risks and risk factors associated with IVCM, while Form 2 had more comprehensive information. Before being presented with the two different informed consent forms, 191 of the 265 patients filled out two other forms evaluating: 1: How they felt in that particular situation/moment (STAI-T); and 2: How they felt independently of the situation or condition at that moment (STAI-S). After the patients were informed, the STAI-T (measuring how they felt in that particular situation) was filled out once more to see if the anxiety level had changed.

Results: The anxiety level for 88 patients receiving Form 1 decreased after they were given the informed consent (P=0.033). However, among the 103 patients receiving Form 2, the anxiety level showed a significant increase (P=0.001) compared to the values obtained before Form 2 was given.

Conclusion: These results indicate that informed consent, including brief information about the risk factors and potential adverse reactions of IVCM, reduces anxiety level, while detailed information before the procedure increases the anxiety level.