ETHICS/EDITORIAL

Is Informed Consent Required for the Administration ofIntravenous Contrast and Similar Clinical Procedures?

Kenneth V. Iserson, MD, MBA From The University of Arizona, Tucson, AZ.

0196-0644/$-see front matterCopyright © 2007 by the American College of Emergency Physicians.doi:10.1016/j.annemergmed.2006.08.018

SEE RELATED ARTICLE, P. 221

[Ann Emerg Med. 2007;49:231-233.]

Aside from their professional responsibility, physicians alsohave a moral and legal obligation to provide their patients withthe information necessary to make informed decisions.Communicating honestly with patients so that they mayparticipate in decisionmaking is a recent, rather than historical,imperative. Based on a respect for patients, this cooperativephysician-patient relationship reverses the time-honoredpaternalism that, since Hippocratic times, has guided physicianinteractions with their patients. In their article, Cowan et al1

imply that emergency physicians should get informed consentfrom their patients before the administration of intravenousradiographic contrast material. To assess this claim, we firstmust review the background for, and the methods of, obtaininginformed consent.

WHAT IS “INFORMED CONSENT”?Rather than merely having a form signed, informed consent

is a communicative process of sharing information withpatients, ascertaining their understanding of the information,and asking for their cooperation and their permission toproceed. Unfortunately, rather than fostering communication asintended, many clinicians view obtaining written informedconsent as an obstacle—they must get a form signed so thatthey can proceed with their work. The form itself oftenencourages this attitude because typically it is printed inimpossibly small type, filled with verbiage too difficult for manypatients to understand, and not read by either the doctor or thepatient.2

WHY DO IT?Medical ethics and professionalism demand that physicians

show respect for patients by acknowledging their autonomy. Wedo this when we help patients use their own values to assesswhether they want a specific diagnostic or therapeuticintervention, according to the physician-provided informationabout treatment options, risks, and benefits.

A legal (risk management) requirement to obtain informed

consent also exists but varies by state. This requirement was first

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explicitly cited in a 1957 case involving the administration ofintravenous contrast when the judge asserted that “[a] physicianviolates his duty to his patient . . . if he withholds any factswhich are necessary to form the basis of an intelligent consentby the patient to the proposed treatment.”3 Virtually all states,either in statute or by common law, now require physicians toinform patients about treatment choices and the associated risksand benefits. The legal standard for the information provided iseither the “community standard” (also known as the“professional community standard” or the “reasonable physicianstandard”) or the “materiality standard” (also known as the“reasonable or prudent or subjective patient standard”). Theformer asks, what would a prudent physician in the samecommunity, with the same background, training, andexperience, have disclosed to a patient in the same or similarsituation? The latter asks, what would a reasonable patient inthe same or similar situation need to know to make anappropriate decision?

HOW IS INFORMED CONSENT OBTAINED?Obtaining informed consent consists of 3 essential

elements4:1. Determining whether patients have decisionmaking capacity

(can understand the options, understand the risks andbenefits to them of the options, and make decisions basedon a stable set of values and goals).5 If the patient lacksdecisionmaking capacity, the surrogate decisionmaker(s)should be given the same information.

2. Providing patients with sufficient information to allow themto make an informed choice.

3. Allowing patients to make their decision voluntarily andwithout coercion.

Although often extremely frustrating for clinicians, apatient’s informed refusal is a natural and expected part of theinformed consent process. In fact, discovering that a patientdoes not think that the risks of a procedure are worth thepotential benefit is a major reason why this communicationprocess exists. A patient’s consent should be documented, andthis should include a description of the information given to thepatient (especially about possible negative outcomes) and whatquestions or answers occurred. Rather than using boilerplate

consent forms, it may be worthwhile to include a short

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Informed Consent Iserson

paragraph about the discussion in the medical record, which ismore easily done when the record is dictated than when it ishandwritten. As bioethicist John Moskop4 noted, “‘blanket’consent forms agreeing to any diagnostic tests or treatments . . .clearly do not satisfy informational requirements because theyprovide little or no information about any specific treatments.”Interactive computer-based video informed consent has beenshown to offer a good alternative to written consent forms foradministration of intravenous contrast materials.6 Suchprograms could be developed to automatically use feedback toassess and document patient understanding.

WHEN IS IT DONE?Even when written informed consent is not required,

communication with the patient about proposed diagnostic andtreatment options is part and parcel of elegant medical practice.In the emergency department (ED), obtaining explicit consentmay be more important than in other practice settings becausepatients often have little control over the practitioner who treatsthem and, especially with emergency medical services–deliveredpatients, may not have chosen the ED in which they are beingtreated.4

There are, of course, significant exceptions to therequirement to obtain informed consent. These includeprocedures for which the risks and benefits are commonknowledge for persons of average intelligence (ie, this often leadsto implied or presumed consent, such as when patients hold outtheir arm to have an intravenous line started). It also includesemergency situations (not just being in the ED) in whichimmediate treatment is required to prevent more serious harm,the patient lacks decisionmaking capacity, and no substitutedecisionmaker (surrogate) is available. Other exceptions includepreexisting knowledge, as when the patient has already learnedthe risks; therapeutic privilege, in which the disclosure processwould “foreclose rational decision” or “pose psychologicaldamage” to the patient; and when the patient explicitly waivesthe right to the information, preferring that the physicianproceed without providing information about the procedure.7

At least one major liability insurer states that “consent shouldbe obtained for all major therapeutic and diagnostic procedureswhere disclosure of significant medical information, includingmajor risks involved, would assist a patient in making anintelligent decision whether to undergo the proposedprocedure.”8 So for which procedures should emergencyphysicians obtain written informed consent? Althoughemergency physicians generally obtain written informed consentbefore performing relatively benign lumbar punctures, thesituation seems to be less consistent for other procedures thatcarry at least as much physical or psychological risk, such ascentral line placement, dislocation reduction, systemicheparinization, intra-articular aspirations or injections, drugs-of-abuse testing, foreign body removal (eye or elsewhere), theinvolvement of trainees in a patient’s care, or the administration

of intravenous contrast.

232 Annals of Emergency Medicine

We know that a wide variation exists in the practice ofobtaining informed consent before the administration ofintravenous contrast, and the need to obtain such consentremains controversial.9 Information about the risks ofintravenous contrast material is not common knowledge amongthe general population,10 and most patients want someinformation before contrast injection; about half view suchinformation as essential.11 Yet in many hospitals and physiciangroups, obtaining such consent is not routine: physiciansassociated with larger hospitals (�250 beds); larger physiciangroups (�10 physicians), no matter what their specialty; anduniversity hospitals use written informed consent less often thanthose in smaller groups, those associated with smaller hospitals,or those in private practice.9 In university settings, radiologytechnologists are most likely to inform patients aboutnonemergency computed tomography (CT) and the possiblerisks, whereas ordering physicians are most likely to informpatients about a CT scan’s purpose.12

The question remains: Should all emergency physicians berequired to obtain informed consent before their patients havestudies with intravenous contrast or any other specificprocedure? The answer depends, as noted above, on applicablelaw and local customary practice. However, so that variation inobtaining formal written informed consent does not exist withinan institution, or at least within the ED, each department(following any institutional guidelines) should develop brief listsof frequently performed procedures that require writteninformed consent. If possible, separate consent forms forcommon procedures that list substantive risks should beavailable to help clinicians provide all necessary information.8

Once the decision is made to obtain formal informed consent,the individual responsible for the procedure, usually the physician,should provide the information, answer questions, and obtain theconsent, although others may help complete the documentation.When necessary, a trained translator should be available to ensureaccurate information transmission.

The key points about formal written informed consent in theED are that differences in local custom, hospital policies, and statelaw lead to a wide variability in which procedures require writteninformed consent and who obtains it. Yet, since patients oftendon’t know information about procedures that we considercommon knowledge, obtaining patient cooperation and consent forprocedures, whether or not one obtains formal written informedconsent, is a vital part of practicing elegant emergency medicine.Basing an ED requirement for informed consent on the relative riskof procedures is fraught with hazards because scant data areavailable. Therefore, the best practice continues to be emphasizingexcellent physician-patient communication.

Supervising editor: Robert K. Knopp, MD

Funding and support: The author reports this study did notreceive any outside funding or support.

Publication dates: Available online November 1, 2006.

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Iserson Informed Consent

Reprints not available from the author.

Address for correspondence: Kenneth V. Iserson, MD, MBA,University of Arizona, 1501 N. Campbell Avenue, POB245057, Tucson, AZ 85724; 520-626-2398, fax 520--626-2480; E-mail kvi@u.arizona.edu.

REFERENCES1. Cowan EA, Calderon Y, Gennis P, et al. Spanish and English video

assisted informed consent for intravenous contrast administrationin the emergency department: a randomized controlled trial. AnnEmerg Med. 2007;49:221-230.

2. Hopper KD, Lambe HA, Shirk SJ. Readability of informed consentforms for use with iodinated contrast media. Radiology. 1993;187:279-283.

3. Salgo v Leland Stanford Jr. University Board of Trustees, 317P.2d 170 (1957).

4. Moskop JC. Informed consent in the emergency department.Emerg Med Clin North Am. 1999;17:327-340.

5. Iserson KV, Sanders AB, Mathieu D. Ethics in Emergency

Medicine. 2nd ed. Tucson, AZ: Galen Press, Ltd; 1995:52.

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6. Hopper KD, Zajdel M, Hulse SF, et al. Interactive method ofinforming patients of the risks of intravenous contrast media.Radiology. 1994;192:67-71.

7. Hall MA, Bobinski MA, Orentlicher D. Health Care Law and Ethics.6th ed. New York, NY: Aspen Publishers; 2003:207–208.

8. CRICO/RMF informed consent. Available at: http//www.rmf.harvard.edu/high-risk-areas/surgery/informed-consent/index.aspx.Accessed August 7, 2006.

9. Lambe HA, Hopper KD, Matthews YL. Use of informed consent forionic and nonionic contrast media. Radiology. 1992;184:145-148.

10. Neptune SM, Hopper KD, Matthews YL. Risks associated with theuse of IV contrast material: analysis of patients’ awareness. Am JRoentgenol. 1994;162:451-454.

11. Hopper KD, Houts PS, McCauslin MA, et al. Patients’ attitudestoward informed consent for intravenous contrast media. InvestRadiol. 1992;27:362-366.

12. Lee CI, Flaster HV, Haims AH, et al. Diagnostic CT scans:institutional informed consent guidelines and practices atacademic medical centers. Am J Roentgenol. 2006;187:282-

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