Informed consent for intravascular administration of contrast material: how much is enough?

To determine the usefulness of informed consent prior to the intravascular administration of contrast material, the authors evaluated four equal groups of patients with different degrees of counseling concerning risks and risk factors. Group 1 was given no information. Group 2 was informed of the common risks in a written statement. Group 3 was informed of all known risks in a written statement. Group 4 was informed of all known risks by means of physician counseling. The average times it took for the technologist (groups 1-3) or the physician (group 4) to counsel the patient and obtain informed consent were 1.7, 6.2, 13.6, and 11.4 minutes, respectively. Counseling by physicians would require approximately 7% of their professional time in a busy radiology department. On a postprocedure test, the patients in groups 1-4 scored on average 38.4%, 68.2%, 63.2%, and 69.8%, respectively. There was no statistical difference in the performance of groups 2-4 on the postprocedure test. If informed consent is to be obtained prior to intravascular administration of contrast material, use of a straightforward written consent form detailing the common risks and risk factors appears to be the best method.