Helen
A. Lambe,
Use and
BS
#{149} Kenneth
oflnformed Nonionic
D. Hopper,
of physician
groups
before
us-
ing intravenous contrast material, regardless of whether it was ionic or nonionic. Nonradiologists were more likely to obtain informed consent before the use of ionic contrast material than radiologists. Regardless of specialty, practices associated with larger hospitals (>250 beds), larger physician groups ( > 10), or a university used informed consent less often than smaller physician groups or those associated with a smaller hospital or a private practice. Though results may be affected by regional variation or increased usage since previous surveys, the use of informed consent
before
the
intravenous
injec-
tion of contrast material is a common practice; it is obtained in the majority of patients. Index terms: Contrast media, Informed consent #{149} Medicolegal Radiology
1992;
complications problems
184:145-148
T
concerning
(1,2)
College
of Medicine
consent
its use
that informed in 30%-35% of intravenous practices
sent the the cause ing verse
(HAL.),
De-
before
lions
have
legal value However, use
have
(1). previous
of informed
larger
physician
practice
groups,
affiliated
physicians,
diologists.
For
Barloon
hospitals
instance,
in
the
(uroradiologists)
was
no study
of informed
obtained
than large
has evaluated
consent
for
a response
rate
to evaluate the for intravenous
by
To our the
administra-
greater
use of informed administration
groups
of three
provider insurance physician
administration
of contrast
This was accomplished by usfiles from Pennsylvania Blue a six-state regional medicare and the largest private medical carrier in Pennsylvania. All groups that billed for the in-
terpretation performed
type
respect for in-
of at least with
material were tensive efforts high response
intravenous
three
procedures contrast
targeted for survey. Exwere made to ensure a rate (over 79%). Ques-
Only
one
METHODS
billed
for
a minimum
involving intravenous These procedures inmaterial-enhanced
five adjoining
com-
(CT), venography, urography.
vania Blue Shield medicare provider
Pennsyl-
is not only the part B for Pennsylvania and
states
but
is also
the largest
private insurance carrier in the state of Pennsylvania. In July 1990, a questionnaire was mailed to each physician (Figure) requesting inconcerning the use of informed consent for the administration of both ionic and nonionic contrast material. A follow-up questionnaire was mailed in formation
August
1990
to those
to the original responders,
with
who
telephone and
did
questionnaire.
a third
not
respond
For the non-
contact
one of the group’s
representative
size,
had
contrast
regardless
group
that
procedures material.
support,
size, with consent
methods
of
The 1989 billing files of Pennsylvania Blue Shield were reviewed to find physi-
of contrast material since that by Spring et al (1) in 1983. We designed a questionnaire to evaluate the medical practice of physicians, of specialty,
AND
intravenous
of
the
consent.
MATERIALS
and/or
radiologists surveyed.
informed
tomography
study
use
and
questionnaire was allowed per physician group, although the responding physician was asked to answer for the entire group.
puted
65%. Finally, there has been no survey, to our knowledge, per-
formed consent
material,
cluded
tion of nonionic contrast material. In addition, we know of no survey that has
contrast
the
ionic
of obtaining such consent, and identification of the individual responsible for
and ra-
group
university-based
knowledge,
nonionic
contrast
diagnostic
concerning
for both
have
university-
and
et al (2), a selective
primarily
the
material
targeted
asked
consent
obtaining
for intravenous
of contrast
primarily
about
were
informed
cian
surveys
consent
administration
use
revealed
consent is only obtained of patients before the use contrast material. Most not obtained such con-
for a variety of reasons, including low probability of a serious reaction; chance that such information may more patient anxiety, thus resultin an increased likelihood of an adreaction; or the lack of medical or
Shield, the
of informed
of practice, or hospital to their use of informed
partment of Radiology (K.D.H.), and Center for Biostatistics and Epidemiology (Y.L.M.), Pennsylvania State University, P0 Box 850, Hershey, PA 17033. Received October 10, 1991; revision requested November 26; revision received January 8, 1992; accepted January 27. Address reprint requests to K.D.H. 67 RSNA, 1992
MA
intravenous administration of contrast material has been and remains a controversial issue. Previous surveys
material. ing data From
L. Matthews,
for Ionic Media’
HE use
travenous
1
#{149} Yvonne
Consent Contrast
The use of informed consent before intravenous administration of contrast material remains a controversial issue. It involves explaining the risks of intravenous contrast material and obtaining the patient’s permission for its use. All physician groups who had billed Pennsylvania Blue Shield for at least three intravenous contrast material-enhanced procedures performed in 1989 were surveyed. Informed consent was obtained from at least some patients by about twothirds
MD
was
physicians
copy
made
to elicit
of the question-
naire was mailed between October 1990 and February 1991. For the approximate 30% of nonresponders as of May 1991, a of each
physician
was contacted and an effort complete the questionnaire
group
was made to by telephone.
Only one completed questionnaire accepted from each physician group. physician quested
was The
completing the form was reto answer for the entire physician
group and to provide information about the type of practice, hospital size, physician group size, and use of informed consent for administration of ionic and nonionic contrast material. The survey included questions about contrast material dures performed ministration
usage (number of proceper day involving ad-
of ionic and nonionic
contrast
145
material),
the use
both
ionic
and
the
reasons
of informed
nonionic
informed
not obtained
before
intravascular
contrast
consent
contrast
for
media,
consent
was
or was
the administration material,
of
and
ques-
tions concerning who provided the information to the patient in an effort to obtain informed consent. Statistical analysis was performed with respect to overall data, radiologists,
nonradiologists,
tice, size of hospital, addition to reviewing
physician sent,
groups
the
type
utilizing
number
of prac-
and group size. the proportion
In of
informed
of patients
Questionnaire sent to each physician group that billed Pennsylvania Blue Shield for at least three trast-enhanced
intravenous procedures
1989. A cover
letter
shown) of the
explained study and
responder
on
physician
-
nature the of the
con-
2.
Do you
3.
If y#{149}s, type a. verbal
whom informed also evalu-
b. (If
of the 1989 Pennsylvania data base revealed 383 phy-
groups
procedures:
phy,
that
had
or venography;
radiology
billed this
urogra-
included
the
veyed,
24
were
physician
343
groups
sur-
to complete
unable
the
gists.
Nine
were radiolononradiolo-
of the nonradiologists
urologists,
and
one
was
four
were
in
sponded,
than
all were
with
vided
the
270 responders
information
on their
type
or
U...
No_
Yes_ Yes_ Yes_ Yes...... Yes_ v...
..ii.pi.
No...... No_ No_ No_ No_. .
I
No_ No......
understand reactions
Ves_ Yes Yes_
No No No_
Yes_ Yes_ Yes_
No_ No_ No......
Who administsrs informsd a. secretary/receptionist b. technologist
consent: Yes Yes_
No_ No
Yes_ Yes_
No_ No_
No......
Yes_
c.
patients causes other
can’t more
_____________
physician
Yes
by more
than
one of the above.
contrast
please
do you
All Some
list
No_
% of each)
non-Ionic
contrast
use
-
They They
cause cause
less pain fewer minor
-
They
cause
fewer
serious
-
They
cause
fewer
life-threatening
-
They
cause
less
-
They
give
better
renal
routinely
for iv Is sued for
pr#{149}medicat#{149}
__%
If you
agents,
do you
us.
them
bacause:
complications complications
complications
toxicity
tissue
opacification
_____________
Other
or another No_
physIcian
monitor
Ionic
contrast
injections?
All
a physician monitors the
12.
this
++
No...... No_ No_ No_ No......
agsnts,
If
of prac-
(20.7%) were in a primarily outpatient office setting. The percentages reflect the checking of multiple categories by some responders. In addition, only about half of the questionnaires had every item completed by the individual responding to the survey. For those re-
No...... with
Yes_
Some
Radiology
does rest?
not
monitor
%
____
non.ionic
contrast
_%
all contrast
injections.
who
nurse
Technologist Other (list)
practice, hospitalin univerpractice, and
university-affiliated
ur
obtaln#{149}d: u.1 Yes..... No_
trouble
or anoth#{149}rphysician monitor injections? Yes_ No_ If yes: All Some
pro-
Ves_ Yes_
returned
Yes_
much
11. Do you
tice, 69 (25.6%) were in private 170 (63.0%) were in primarily based practice, 12 (4.4%) were sity
No_ No
of the form
you us. Ionic with steroids? Yes_ No_ If yes.
fewer
who
a copy
If
10 physicians.
Among
appreciate
No_
10. Do you Yes_ if yes.
practice practice). who re-
in groups
Ves we would
8.
were
(three were in an office-based and one was in a university Among the nonradiologists
No_
not you use lnformad consent It could help a physIcian who intravenous iodine? know_
9.
practice
Yes_
Regardless of whether or contrast. do you believe a known complicatIon of Yes_ No_ Don’t
a neurologist.
private
nonionic
Non-Ionic
7.
Of the eight nonradiologists who provided information as to the type of their practice,
and
cons#{149}ntobtaln.d.
(If performed
material (billing error). Among the remaining 359 physician groups, responses were obtained from 285 (79.4%). Of the 268 (94.0%) 14 (4.9%) were
ionic
Yes
c.
questionnaire because of no forwarding address, retirement (solo practice), or a group’s nonuse of intravenous contrast
responders, gists and
both
Yes_
too
e 6.
383
br
cons#{149}ntfor IV contrast? Yes...... No
written
b 4.
groups.
Among
questions
Reasons Informed consent not a risk of complications remote
5.
for at least
CT, excretory
followIng
Intormid
CONTRAST
proc#{149}durs p.r day 91. with non-sonic contrast
Reasons Informed consanl obtaln#{149}d? a. legal protection Yes b. standard of care in communityYes c. patientsright to know Yes.... d. good medicine Ves e. other _____________ Yes_
RESULTS
three
the
obtain
written. survey) 4.
sician
answer
(IV)
[aSIC
ated.
A review Blue Shield
INTRAVENOUS
TYPE OF PRACTICE (Chick all that apply) Group (I In group: Prlvat#{149}Practlc. Unlvarslty Ofllc#{149}/Out.Patlant _ Hospital (I of b.ds
M.dlclna
lOfliC
Please contrast
group.
undergoing
these procedures-from consent was obtained-was
IODINATED
numbar iv contrast contrast
Avirag. 96 with
1.
the
behalf
FOR
Radiology Urology N#{149}urology Family S Community Othsr (list):__________
-
to complete
questionnaire
entire
conin
(not
the asked
CONSENT
INFORMED
SPECIALTY:
13. If you
do not
us.
non.ionic
contrast
for all
patIents a choice of contrast agents? Yes_
patients,
do you
offsr
No_
56
sponders average Radiology
larger
providing information, the group size was 11.3 physicians. groups tended to be much
than
performed enhanced Most
those
a greater procedures. physicians
vey obtain
informed
of nonradiologists number included
consent
before
use of intravenous contrast material from at least some of their patients. ranges from 196 physician groups (68.8%) administering ionic contrast
terial
to 191 (67.0%)
146
Radiology
for those
using
agents
many physician informed consent
only
2,477
dergoing
and
of contrastin this
nonionic
sur-
the This ma-
(Table
1).
groups from
do not obtain every patient,
of 4,392
patients
(P < .02 both ionic and nonionic), and physicians associated with larger hospitals (P < .002 for both ionic and
Because
(56.4%)
contrast-enhanced
un-
procedures
daily by these physician would have been asked for informed consent. A greater proportion of nonradiolo-
nonionic contrast-enhanced dures) tended to obtain
proceinformed con-
performed
sent
groups
findings
gists
regardless of whether the proportion of physician groups or the number of patients undergoing contrast-enhanced
versus
radiologists
obtain
consent for ionic contrast-enhanced procedures. However, radiologists far more likely to obtain informed
informed
on a less
procedures are con-
sent for nomonic contrast-enhanced procedures. Larger physician groups (P < .02 ionic, P = .08 nonionic), university-affiliated physician groups
frequent
were
statistically
basis.
These
significant
is considered.
The most common method of informing the patient and obtaining consent was in writing, with 257 (90.2%) and 269 (94.4%) physician groups using written informed consent for ionic and nonionic contrast-enhanced procedures, respec-
July
1992
for both trast-enhanced
ionic and nonionic conprocedures. However,
time
Table
1 Consent
Informed
for the Use of Contrast
Material IoniC
nonradiologists
COfltTSSt
Nonionic Contrast Mateal
Ma
No. of
Physician Group Characteristics
Physician
Physician Groups
and
physicians informed
used consent
Physicians
in
university-affiliated
a technologist only 50%
office-based
to obtain of the time. practices,
who
Overall
285
68.8
56.4
67.0
57.6
used ionic contrast material, had secretaries or receptionists obtain informed consent 21 % of the time. This was a much greater use of secretaries or recep-
Radiologists
268
67.8
558
67.3
57.6
89 61
O 56
0* 40
tionists
Physician
Groups
Procedures
(%)
Groups
Procedures
(%)*
(%)t
(%)*
Nonradiologists
14
Private practice Office-based prac-
69
83 64
56
68
60
67
39
88 77
83 50
76 38
82 53
72 57
12
40
35
33
16
69.1
65.5
68.2
62.6
44
32
48
44
Uce Hospital
practice
25Obeds
University
Size of group < 10 physicians
113
>lOphysicians
40
in the totaJsre&Cb
e Variance sicians. t Percentage
reflects
the noncompletion
the numberofgroups
using
alaS
ofthe
portions
informed
consent
questionnaire
by several
veraus the total number was requested proportion
of
phy-
of versus
tively.
Again,
however,
there
was
and, of those asked, 94% receive written information on the procedure before they give consent. This percentage is the same for those who undergo either ionic or nonionic contrast-enhanced procedures. However, the same is not true for the 32 patients undergoing contrast-enhanced procedures performed daily by nonradiologists. Only 40% and 0% of these patients receive written information before giving consent for the
(ionic) of the time, versus 100% (nonionic) and 70% (ionic) of the time for nonradiologists. The six university-affiliated physician groups using informed consent tended to use verbal informed consent the least, with one (16.7%) using it for nonionic and two (33.3%) for ionic contrast-enhanced procedures. For those obtaining informed consent, common reasons included legal protection, standard of care, patient’s right to know, and good medicine (Table 2). These reasons did not seem to vary between those administering ionic and nonionic contrast agents. Univer-
use
sity-affiliated
of ionic
and
nonionic
dia, respectively. gists
used
contrast
However,
nonionic
me-
nonradiolo-
contrast
material
in
only
a small proportion of their patients (13%). Thus, a larger survey is necessary to accurately determine the use of informed consent by nonradiologists who use nonionic contrast material. ference between radiologists
diologists consent
procedures When informing consent, physician consent
in the use of written for ionic
The and
difnonra-
informed
contrast-enhanced significant (P < .001).
was questioned about the use of the patient verbally to obtain 114 (40.0%) and 119 (41.8%) groups use verbal informed for ionic and nonionic contrast-
enhanced procedures, respectively. The overlap between those who use written versus verbal consent resulted because many physicians completing the questionnaires
checked
substantial
Volume
both.
difference
184
e Number
There
between
1
was a radiolo-
physicians
tended
to rate
standard of care as a less important reason for obtaining informed consent (ionic, 40.0%; nonionic, 75.0%). When specifically questioned as to whether informed cian sued
consent would for malpractice
help a physibecause of an
adverse reaction in a patient to the contrast material, only 156 (54.7%) responded affirmatively. Among those physicians not obtaining informed consent, the two most common reasons were that remote risks existed and that informing individuals might actually increase the probability of a reaction (Table 3). Other common reasons given for not obtaining informed consent included too much trouble, too difficult for patients to understand,
and
not
legally
binding.
Most commonly, the person who obtamed informed consent was a technologist
who
counseled
patients
settings
were
far
more
DISCUSSION
and nonradiologists regarding the use of verbal consent, with radiologists using it only 42% (nonionic) and 38%
procedures performed daily by one of the physician groups, only 2,477 patients are asked for informed consent,
physicians
patients.
gists
con-
between radiologists Among the 4,392 contrast-enhanced
practice
the
Our
siderable variation and nonradiologists. patients undergoing
other
likely to obtain informed consent themselves or use another physician (P < .03). Although overall physician counseling for informed consent was found 63% (ionic) and 60% (nonionic) of the time, university-affiliated physicians and nonradiologists obtained such consent themselves 75%-100% of the time.
groups.
* Percentage reflects the number ofpafientsfromwhominfonnedconeent total number ofprocedures. * Nonradiologists used nonioniccontraet material inonly a small
in
sity-affiliated
affil-
iated
than
(P < .02). Although office-based practices were less likely to use physicians for obtaining informed consent (P < .01), nonradiologists and univer-
78%
of
the
results
indicate
a much
greater
use of informed consent for intravenous contrast material than that previously reported. Spring et al (1) found that only 34% of radiologists in large U.S. hospitals ( > 100 beds) obtained consent, either verbally or written. However, this study was limited to larger hospitals and, as a result, larger practice groups;
it only
surveyed
diagnostic
radiologists
and excluded physicians practicing in a primarily outpatient clinic setting. Our study indicates that physicians practicing in larger hospitals, those associated with larger groups, and those who are primarily hospital based are less likely to obtain informed consent. Also, the survey by Spring et at (1) was performed in 1983 and might not allow for changes in practice patterns that may have occurred since then. In 1989, Barloon et at (2) surveyed 89
U.S. and
Canadian
members
of the Soci-
ety of Uroradiology. Of the 58 members who responded, only 17 (29%) obtained written consent before the use of intravenous contrast material. The responders were primarily from large university hospitals and were radiologists likely associated with large physician practice groups. The proportion of these physicians who used informed consent (29%) is similar
to our
findings
in
these
catego-
ries. However, when all physicians using intravenous contrast material are included, a much higher use of informed consent is found. Our results show a much higher rate of obtaining informed consent than either Spring et at (1) or Barloon et al (2), ranging
from
67%
and ionic contrast These differences
to 69%
for
nonionic
material, respectively. may be due partly to
Radiology
e
147
our
use
of a wide
cross
section
of physi-
cians using contrast material. Essentially, we surveyed any physician group that billed Pennsylvania Blue Shield for intravenous contrastenhanced procedures in 1989. Our survey included all specialties using intravenous contrast material, all practice types
(hospital,
based),
and
university, a variety
and
office-
of hospital
and
group sizes. In addition, our data may reflect changing practice patterns since the previous studies were conducted. The greatest use of informed consent for the use of intravenous contrast agents is among private outpatient physician
practices,
beds),
and
(
smaller
smaller
10 physicians).
(
hospitals
physician There
250
groups
use of
is less
informed consent among larger physician groups, university-affiliated physicians, and larger hospitals, although the rate for large hospitals (50%) is higher than it was 7 years ago (1). Among radiologists, use of informed consent for contrast-enhanced procedures did not vary significantly for ionic versus nonionic contrast agents. However, nonradiologists were more likely to obtam informed consent for ionic versus nonionic contrast-enhanced procedures. The use of informed consent continues to be a debated issue (1-9). One of the primary arguments for obtaining consent is a legal one. In our survey, more than 65% of physicians obtained informed consent because of “standard of care.” Traditionally, a “ reasonable physician” standard has been applied, requiring that patients be informed of what a reasonable physician thinks is appropriate for them to know. However, more recently, many states have adopted a “ reasonable patient” standard that requires a patient to be informed of what a reasonable patient would want to know under the circumstances
(3,4).
However,
as
there
is no
national standard, the courts must base judgments on either the physician or patient standard, depending on state law. Our finding that most physician groups,
at least
in
the
northeastern
United States, are obtaining informed consent may indicate that, regardless of which standard is applied, such consent perhaps should be obtained from all patients. One of the primary arguments used for not informing patients of the risks of contrast material is the potential for increasing anxiety and, thus, the potential for serious reactions. In our survey, more than 50% of physicians who did
not obtain that
informed
to inform
148 #{149} Radiology
the
consent patient
believed might
cause
more reactions. Lalli (5) demonstrated that central nervous system changes caused by anxiety may increase the occurrence of self-limiting minor reactions (nausea, vomiting) among patients informed of the risks of contrast material. However, he found no statistical increase in serious reactions either be-
cause
of an insufficient
number
of pa-
or because an increase did not exist. Spring et al (1) found no substantial increase in the number of major reactions among patients who were informed of the risks of contrast material. tients
A new
formed
tion
argument
consent
of contrast
for
before
material
the
use
the
administra-
of in-
is the availabit-
ity of nonionic contrast adds a new dimension
agents. This to the question
of whether
should
physicians
the
necessity
to inform
by
Our
physicians
discovery who
of a decreased are
Unless the use of nonionic agents becomes universal, the standard of care may be to inform patients of the relative
risks
between
the two
types
of contrast
agents and to offer a choice to those at low-risk for a reaction and to make those receiving nonionic contrast material aware of the increased cost to their health insurance and ultimately to themselves. #{149}
1.
2.
3.
(10).
However, our survey found that presentty only 16% of physician groups offer their patients a choice of using nonionic contrast material. In conclusion, we found that most physician groups using intravenous contrast material obtain informed consent. There is no statistically significant variation between the use of informed consent for ionic and nonionic contrast material. When used, informed consent is obtamed for both medical and legal rea-
sons.
of possible reactions when administering the standard ionic contrast material.
References
inform
low-risk patients who are to undergo ionic contrast-enhanced procedures of not only the risks but also of the availability of an alternative, lower risk contrast agent. The fact that there is a safer, although more expensive, alternative increases
addition, changing practice patterns are likely to be at least partly responsible. With the use of the newer and safer nonionic contrast agents, there is an increased need to inform low-risk patients
4.
5. 6. 7.
8.
9.
use
university-affil-
10.
Spring DB, Atkin JR. Margulis AR. Informed consent for intravenous contrast-enhanced radiology: a national survey of practice and opinion. Radiology 1984; 152:609-613. Barloon TJ, Brown RC, Berbaum KS. Current status of adult uroradiology: a survey of members of the Society of Uroradiology. AJR 1990; 154:301-304. Sprung CL, Winick BJ. Informed consent in theory and practice: legal and medical perspectlves on the informed consent doctrine and proposed reconceptualization. Crit Care Med 19g9; 17:1346-134. Bettmann MA, Holzer JF, Trombly ST. Risk management issues related to the use of contrast agents. Radiology 1990; 175:629-631. Lalli AF. Urographic contrast media reactions and anxiety. Radiology 1974; 112:267-271. Bush WH. Informed consent for contrast media. AJR 1989; 152:867-869. Spring DB, Winfield AC, Friedland GW, Shuman WP, Preger L. Written informed consent for IV contrast-enhanced radiography: patients attitudes and common limitations. AJR 1988; 151:1243-1245. Jacobsen PD, Rosenquist CJ. The introduction of low osmolar contrast agents in radiology: medical, economic, legal and public po1icy issues. JAMA 1988; 260:1586-1592. Reuter SR. An overview of informed consent for radiologists. AJR 1987; 148:219-227. Miller CJ. Informed consent. II. JAMA 1980; 244:2347.
iated
and associated with larger practice groups and/or larger hospitals helps explain the disagreement between our results and those of previous surveys. In
July
1992
A. Lambe,
Use and
BS
#{149} Kenneth
oflnformed Nonionic
D. Hopper,
of physician
groups
before
us-
ing intravenous contrast material, regardless of whether it was ionic or nonionic. Nonradiologists were more likely to obtain informed consent before the use of ionic contrast material than radiologists. Regardless of specialty, practices associated with larger hospitals (>250 beds), larger physician groups ( > 10), or a university used informed consent less often than smaller physician groups or those associated with a smaller hospital or a private practice. Though results may be affected by regional variation or increased usage since previous surveys, the use of informed consent
before
the
intravenous
injec-
tion of contrast material is a common practice; it is obtained in the majority of patients. Index terms: Contrast media, Informed consent #{149} Medicolegal Radiology
1992;
complications problems
184:145-148
T
concerning
(1,2)
College
of Medicine
consent
its use
that informed in 30%-35% of intravenous practices
sent the the cause ing verse
(HAL.),
De-
before
lions
have
legal value However, use
have
(1). previous
of informed
larger
physician
practice
groups,
affiliated
physicians,
diologists.
For
Barloon
hospitals
instance,
in
the
(uroradiologists)
was
no study
of informed
obtained
than large
has evaluated
consent
for
a response
rate
to evaluate the for intravenous
by
To our the
administra-
greater
use of informed administration
groups
of three
provider insurance physician
administration
of contrast
This was accomplished by usfiles from Pennsylvania Blue a six-state regional medicare and the largest private medical carrier in Pennsylvania. All groups that billed for the in-
terpretation performed
type
respect for in-
of at least with
material were tensive efforts high response
intravenous
three
procedures contrast
targeted for survey. Exwere made to ensure a rate (over 79%). Ques-
Only
one
METHODS
billed
for
a minimum
involving intravenous These procedures inmaterial-enhanced
five adjoining
com-
(CT), venography, urography.
vania Blue Shield medicare provider
Pennsyl-
is not only the part B for Pennsylvania and
states
but
is also
the largest
private insurance carrier in the state of Pennsylvania. In July 1990, a questionnaire was mailed to each physician (Figure) requesting inconcerning the use of informed consent for the administration of both ionic and nonionic contrast material. A follow-up questionnaire was mailed in formation
August
1990
to those
to the original responders,
with
who
telephone and
did
questionnaire.
a third
not
respond
For the non-
contact
one of the group’s
representative
size,
had
contrast
regardless
group
that
procedures material.
support,
size, with consent
methods
of
The 1989 billing files of Pennsylvania Blue Shield were reviewed to find physi-
of contrast material since that by Spring et al (1) in 1983. We designed a questionnaire to evaluate the medical practice of physicians, of specialty,
AND
intravenous
of
the
consent.
MATERIALS
and/or
radiologists surveyed.
informed
tomography
study
use
and
questionnaire was allowed per physician group, although the responding physician was asked to answer for the entire group.
puted
65%. Finally, there has been no survey, to our knowledge, per-
formed consent
material,
cluded
tion of nonionic contrast material. In addition, we know of no survey that has
contrast
the
ionic
of obtaining such consent, and identification of the individual responsible for
and ra-
group
university-based
knowledge,
nonionic
contrast
diagnostic
concerning
for both
have
university-
and
et al (2), a selective
primarily
the
material
targeted
asked
consent
obtaining
for intravenous
of contrast
primarily
about
were
informed
cian
surveys
consent
administration
use
revealed
consent is only obtained of patients before the use contrast material. Most not obtained such con-
for a variety of reasons, including low probability of a serious reaction; chance that such information may more patient anxiety, thus resultin an increased likelihood of an adreaction; or the lack of medical or
Shield, the
of informed
of practice, or hospital to their use of informed
partment of Radiology (K.D.H.), and Center for Biostatistics and Epidemiology (Y.L.M.), Pennsylvania State University, P0 Box 850, Hershey, PA 17033. Received October 10, 1991; revision requested November 26; revision received January 8, 1992; accepted January 27. Address reprint requests to K.D.H. 67 RSNA, 1992
MA
intravenous administration of contrast material has been and remains a controversial issue. Previous surveys
material. ing data From
L. Matthews,
for Ionic Media’
HE use
travenous
1
#{149} Yvonne
Consent Contrast
The use of informed consent before intravenous administration of contrast material remains a controversial issue. It involves explaining the risks of intravenous contrast material and obtaining the patient’s permission for its use. All physician groups who had billed Pennsylvania Blue Shield for at least three intravenous contrast material-enhanced procedures performed in 1989 were surveyed. Informed consent was obtained from at least some patients by about twothirds
MD
was
physicians
copy
made
to elicit
of the question-
naire was mailed between October 1990 and February 1991. For the approximate 30% of nonresponders as of May 1991, a of each
physician
was contacted and an effort complete the questionnaire
group
was made to by telephone.
Only one completed questionnaire accepted from each physician group. physician quested
was The
completing the form was reto answer for the entire physician
group and to provide information about the type of practice, hospital size, physician group size, and use of informed consent for administration of ionic and nonionic contrast material. The survey included questions about contrast material dures performed ministration
usage (number of proceper day involving ad-
of ionic and nonionic
contrast
145
material),
the use
both
ionic
and
the
reasons
of informed
nonionic
informed
not obtained
before
intravascular
contrast
consent
contrast
for
media,
consent
was
or was
the administration material,
of
and
ques-
tions concerning who provided the information to the patient in an effort to obtain informed consent. Statistical analysis was performed with respect to overall data, radiologists,
nonradiologists,
tice, size of hospital, addition to reviewing
physician sent,
groups
the
type
utilizing
number
of prac-
and group size. the proportion
In of
informed
of patients
Questionnaire sent to each physician group that billed Pennsylvania Blue Shield for at least three trast-enhanced
intravenous procedures
1989. A cover
letter
shown) of the
explained study and
responder
on
physician
-
nature the of the
con-
2.
Do you
3.
If y#{149}s, type a. verbal
whom informed also evalu-
b. (If
of the 1989 Pennsylvania data base revealed 383 phy-
groups
procedures:
phy,
that
had
or venography;
radiology
billed this
urogra-
included
the
veyed,
24
were
physician
343
groups
sur-
to complete
unable
the
gists.
Nine
were radiolononradiolo-
of the nonradiologists
urologists,
and
one
was
four
were
in
sponded,
than
all were
with
vided
the
270 responders
information
on their
type
or
U...
No_
Yes_ Yes_ Yes_ Yes...... Yes_ v...
..ii.pi.
No...... No_ No_ No_ No_. .
I
No_ No......
understand reactions
Ves_ Yes Yes_
No No No_
Yes_ Yes_ Yes_
No_ No_ No......
Who administsrs informsd a. secretary/receptionist b. technologist
consent: Yes Yes_
No_ No
Yes_ Yes_
No_ No_
No......
Yes_
c.
patients causes other
can’t more
_____________
physician
Yes
by more
than
one of the above.
contrast
please
do you
All Some
list
No_
% of each)
non-Ionic
contrast
use
-
They They
cause cause
less pain fewer minor
-
They
cause
fewer
serious
-
They
cause
fewer
life-threatening
-
They
cause
less
-
They
give
better
renal
routinely
for iv Is sued for
pr#{149}medicat#{149}
__%
If you
agents,
do you
us.
them
bacause:
complications complications
complications
toxicity
tissue
opacification
_____________
Other
or another No_
physIcian
monitor
Ionic
contrast
injections?
All
a physician monitors the
12.
this
++
No...... No_ No_ No_ No......
agsnts,
If
of prac-
(20.7%) were in a primarily outpatient office setting. The percentages reflect the checking of multiple categories by some responders. In addition, only about half of the questionnaires had every item completed by the individual responding to the survey. For those re-
No...... with
Yes_
Some
Radiology
does rest?
not
monitor
%
____
non.ionic
contrast
_%
all contrast
injections.
who
nurse
Technologist Other (list)
practice, hospitalin univerpractice, and
university-affiliated
ur
obtaln#{149}d: u.1 Yes..... No_
trouble
or anoth#{149}rphysician monitor injections? Yes_ No_ If yes: All Some
pro-
Ves_ Yes_
returned
Yes_
much
11. Do you
tice, 69 (25.6%) were in private 170 (63.0%) were in primarily based practice, 12 (4.4%) were sity
No_ No
of the form
you us. Ionic with steroids? Yes_ No_ If yes.
fewer
who
a copy
If
10 physicians.
Among
appreciate
No_
10. Do you Yes_ if yes.
practice practice). who re-
in groups
Ves we would
8.
were
(three were in an office-based and one was in a university Among the nonradiologists
No_
not you use lnformad consent It could help a physIcian who intravenous iodine? know_
9.
practice
Yes_
Regardless of whether or contrast. do you believe a known complicatIon of Yes_ No_ Don’t
a neurologist.
private
nonionic
Non-Ionic
7.
Of the eight nonradiologists who provided information as to the type of their practice,
and
cons#{149}ntobtaln.d.
(If performed
material (billing error). Among the remaining 359 physician groups, responses were obtained from 285 (79.4%). Of the 268 (94.0%) 14 (4.9%) were
ionic
Yes
c.
questionnaire because of no forwarding address, retirement (solo practice), or a group’s nonuse of intravenous contrast
responders, gists and
both
Yes_
too
e 6.
383
br
cons#{149}ntfor IV contrast? Yes...... No
written
b 4.
groups.
Among
questions
Reasons Informed consent not a risk of complications remote
5.
for at least
CT, excretory
followIng
Intormid
CONTRAST
proc#{149}durs p.r day 91. with non-sonic contrast
Reasons Informed consanl obtaln#{149}d? a. legal protection Yes b. standard of care in communityYes c. patientsright to know Yes.... d. good medicine Ves e. other _____________ Yes_
RESULTS
three
the
obtain
written. survey) 4.
sician
answer
(IV)
[aSIC
ated.
A review Blue Shield
INTRAVENOUS
TYPE OF PRACTICE (Chick all that apply) Group (I In group: Prlvat#{149}Practlc. Unlvarslty Ofllc#{149}/Out.Patlant _ Hospital (I of b.ds
M.dlclna
lOfliC
Please contrast
group.
undergoing
these procedures-from consent was obtained-was
IODINATED
numbar iv contrast contrast
Avirag. 96 with
1.
the
behalf
FOR
Radiology Urology N#{149}urology Family S Community Othsr (list):__________
-
to complete
questionnaire
entire
conin
(not
the asked
CONSENT
INFORMED
SPECIALTY:
13. If you
do not
us.
non.ionic
contrast
for all
patIents a choice of contrast agents? Yes_
patients,
do you
offsr
No_
56
sponders average Radiology
larger
providing information, the group size was 11.3 physicians. groups tended to be much
than
performed enhanced Most
those
a greater procedures. physicians
vey obtain
informed
of nonradiologists number included
consent
before
use of intravenous contrast material from at least some of their patients. ranges from 196 physician groups (68.8%) administering ionic contrast
terial
to 191 (67.0%)
146
Radiology
for those
using
agents
many physician informed consent
only
2,477
dergoing
and
of contrastin this
nonionic
sur-
the This ma-
(Table
1).
groups from
do not obtain every patient,
of 4,392
patients
(P < .02 both ionic and nonionic), and physicians associated with larger hospitals (P < .002 for both ionic and
Because
(56.4%)
contrast-enhanced
un-
procedures
daily by these physician would have been asked for informed consent. A greater proportion of nonradiolo-
nonionic contrast-enhanced dures) tended to obtain
proceinformed con-
performed
sent
groups
findings
gists
regardless of whether the proportion of physician groups or the number of patients undergoing contrast-enhanced
versus
radiologists
obtain
consent for ionic contrast-enhanced procedures. However, radiologists far more likely to obtain informed
informed
on a less
procedures are con-
sent for nomonic contrast-enhanced procedures. Larger physician groups (P < .02 ionic, P = .08 nonionic), university-affiliated physician groups
frequent
were
statistically
basis.
These
significant
is considered.
The most common method of informing the patient and obtaining consent was in writing, with 257 (90.2%) and 269 (94.4%) physician groups using written informed consent for ionic and nonionic contrast-enhanced procedures, respec-
July
1992
for both trast-enhanced
ionic and nonionic conprocedures. However,
time
Table
1 Consent
Informed
for the Use of Contrast
Material IoniC
nonradiologists
COfltTSSt
Nonionic Contrast Mateal
Ma
No. of
Physician Group Characteristics
Physician
Physician Groups
and
physicians informed
used consent
Physicians
in
university-affiliated
a technologist only 50%
office-based
to obtain of the time. practices,
who
Overall
285
68.8
56.4
67.0
57.6
used ionic contrast material, had secretaries or receptionists obtain informed consent 21 % of the time. This was a much greater use of secretaries or recep-
Radiologists
268
67.8
558
67.3
57.6
89 61
O 56
0* 40
tionists
Physician
Groups
Procedures
(%)
Groups
Procedures
(%)*
(%)t
(%)*
Nonradiologists
14
Private practice Office-based prac-
69
83 64
56
68
60
67
39
88 77
83 50
76 38
82 53
72 57
12
40
35
33
16
69.1
65.5
68.2
62.6
44
32
48
44
Uce Hospital
practice
25Obeds
University
Size of group < 10 physicians
113
>lOphysicians
40
in the totaJsre&Cb
e Variance sicians. t Percentage
reflects
the noncompletion
the numberofgroups
using
alaS
ofthe
portions
informed
consent
questionnaire
by several
veraus the total number was requested proportion
of
phy-
of versus
tively.
Again,
however,
there
was
and, of those asked, 94% receive written information on the procedure before they give consent. This percentage is the same for those who undergo either ionic or nonionic contrast-enhanced procedures. However, the same is not true for the 32 patients undergoing contrast-enhanced procedures performed daily by nonradiologists. Only 40% and 0% of these patients receive written information before giving consent for the
(ionic) of the time, versus 100% (nonionic) and 70% (ionic) of the time for nonradiologists. The six university-affiliated physician groups using informed consent tended to use verbal informed consent the least, with one (16.7%) using it for nonionic and two (33.3%) for ionic contrast-enhanced procedures. For those obtaining informed consent, common reasons included legal protection, standard of care, patient’s right to know, and good medicine (Table 2). These reasons did not seem to vary between those administering ionic and nonionic contrast agents. Univer-
use
sity-affiliated
of ionic
and
nonionic
dia, respectively. gists
used
contrast
However,
nonionic
me-
nonradiolo-
contrast
material
in
only
a small proportion of their patients (13%). Thus, a larger survey is necessary to accurately determine the use of informed consent by nonradiologists who use nonionic contrast material. ference between radiologists
diologists consent
procedures When informing consent, physician consent
in the use of written for ionic
The and
difnonra-
informed
contrast-enhanced significant (P < .001).
was questioned about the use of the patient verbally to obtain 114 (40.0%) and 119 (41.8%) groups use verbal informed for ionic and nonionic contrast-
enhanced procedures, respectively. The overlap between those who use written versus verbal consent resulted because many physicians completing the questionnaires
checked
substantial
Volume
both.
difference
184
e Number
There
between
1
was a radiolo-
physicians
tended
to rate
standard of care as a less important reason for obtaining informed consent (ionic, 40.0%; nonionic, 75.0%). When specifically questioned as to whether informed cian sued
consent would for malpractice
help a physibecause of an
adverse reaction in a patient to the contrast material, only 156 (54.7%) responded affirmatively. Among those physicians not obtaining informed consent, the two most common reasons were that remote risks existed and that informing individuals might actually increase the probability of a reaction (Table 3). Other common reasons given for not obtaining informed consent included too much trouble, too difficult for patients to understand,
and
not
legally
binding.
Most commonly, the person who obtamed informed consent was a technologist
who
counseled
patients
settings
were
far
more
DISCUSSION
and nonradiologists regarding the use of verbal consent, with radiologists using it only 42% (nonionic) and 38%
procedures performed daily by one of the physician groups, only 2,477 patients are asked for informed consent,
physicians
patients.
gists
con-
between radiologists Among the 4,392 contrast-enhanced
practice
the
Our
siderable variation and nonradiologists. patients undergoing
other
likely to obtain informed consent themselves or use another physician (P < .03). Although overall physician counseling for informed consent was found 63% (ionic) and 60% (nonionic) of the time, university-affiliated physicians and nonradiologists obtained such consent themselves 75%-100% of the time.
groups.
* Percentage reflects the number ofpafientsfromwhominfonnedconeent total number ofprocedures. * Nonradiologists used nonioniccontraet material inonly a small
in
sity-affiliated
affil-
iated
than
(P < .02). Although office-based practices were less likely to use physicians for obtaining informed consent (P < .01), nonradiologists and univer-
78%
of
the
results
indicate
a much
greater
use of informed consent for intravenous contrast material than that previously reported. Spring et al (1) found that only 34% of radiologists in large U.S. hospitals ( > 100 beds) obtained consent, either verbally or written. However, this study was limited to larger hospitals and, as a result, larger practice groups;
it only
surveyed
diagnostic
radiologists
and excluded physicians practicing in a primarily outpatient clinic setting. Our study indicates that physicians practicing in larger hospitals, those associated with larger groups, and those who are primarily hospital based are less likely to obtain informed consent. Also, the survey by Spring et at (1) was performed in 1983 and might not allow for changes in practice patterns that may have occurred since then. In 1989, Barloon et at (2) surveyed 89
U.S. and
Canadian
members
of the Soci-
ety of Uroradiology. Of the 58 members who responded, only 17 (29%) obtained written consent before the use of intravenous contrast material. The responders were primarily from large university hospitals and were radiologists likely associated with large physician practice groups. The proportion of these physicians who used informed consent (29%) is similar
to our
findings
in
these
catego-
ries. However, when all physicians using intravenous contrast material are included, a much higher use of informed consent is found. Our results show a much higher rate of obtaining informed consent than either Spring et at (1) or Barloon et al (2), ranging
from
67%
and ionic contrast These differences
to 69%
for
nonionic
material, respectively. may be due partly to
Radiology
e
147
our
use
of a wide
cross
section
of physi-
cians using contrast material. Essentially, we surveyed any physician group that billed Pennsylvania Blue Shield for intravenous contrastenhanced procedures in 1989. Our survey included all specialties using intravenous contrast material, all practice types
(hospital,
based),
and
university, a variety
and
office-
of hospital
and
group sizes. In addition, our data may reflect changing practice patterns since the previous studies were conducted. The greatest use of informed consent for the use of intravenous contrast agents is among private outpatient physician
practices,
beds),
and
(
smaller
smaller
10 physicians).
(
hospitals
physician There
250
groups
use of
is less
informed consent among larger physician groups, university-affiliated physicians, and larger hospitals, although the rate for large hospitals (50%) is higher than it was 7 years ago (1). Among radiologists, use of informed consent for contrast-enhanced procedures did not vary significantly for ionic versus nonionic contrast agents. However, nonradiologists were more likely to obtam informed consent for ionic versus nonionic contrast-enhanced procedures. The use of informed consent continues to be a debated issue (1-9). One of the primary arguments for obtaining consent is a legal one. In our survey, more than 65% of physicians obtained informed consent because of “standard of care.” Traditionally, a “ reasonable physician” standard has been applied, requiring that patients be informed of what a reasonable physician thinks is appropriate for them to know. However, more recently, many states have adopted a “ reasonable patient” standard that requires a patient to be informed of what a reasonable patient would want to know under the circumstances
(3,4).
However,
as
there
is no
national standard, the courts must base judgments on either the physician or patient standard, depending on state law. Our finding that most physician groups,
at least
in
the
northeastern
United States, are obtaining informed consent may indicate that, regardless of which standard is applied, such consent perhaps should be obtained from all patients. One of the primary arguments used for not informing patients of the risks of contrast material is the potential for increasing anxiety and, thus, the potential for serious reactions. In our survey, more than 50% of physicians who did
not obtain that
informed
to inform
148 #{149} Radiology
the
consent patient
believed might
cause
more reactions. Lalli (5) demonstrated that central nervous system changes caused by anxiety may increase the occurrence of self-limiting minor reactions (nausea, vomiting) among patients informed of the risks of contrast material. However, he found no statistical increase in serious reactions either be-
cause
of an insufficient
number
of pa-
or because an increase did not exist. Spring et al (1) found no substantial increase in the number of major reactions among patients who were informed of the risks of contrast material. tients
A new
formed
tion
argument
consent
of contrast
for
before
material
the
use
the
administra-
of in-
is the availabit-
ity of nonionic contrast adds a new dimension
agents. This to the question
of whether
should
physicians
the
necessity
to inform
by
Our
physicians
discovery who
of a decreased are
Unless the use of nonionic agents becomes universal, the standard of care may be to inform patients of the relative
risks
between
the two
types
of contrast
agents and to offer a choice to those at low-risk for a reaction and to make those receiving nonionic contrast material aware of the increased cost to their health insurance and ultimately to themselves. #{149}
1.
2.
3.
(10).
However, our survey found that presentty only 16% of physician groups offer their patients a choice of using nonionic contrast material. In conclusion, we found that most physician groups using intravenous contrast material obtain informed consent. There is no statistically significant variation between the use of informed consent for ionic and nonionic contrast material. When used, informed consent is obtamed for both medical and legal rea-
sons.
of possible reactions when administering the standard ionic contrast material.
References
inform
low-risk patients who are to undergo ionic contrast-enhanced procedures of not only the risks but also of the availability of an alternative, lower risk contrast agent. The fact that there is a safer, although more expensive, alternative increases
addition, changing practice patterns are likely to be at least partly responsible. With the use of the newer and safer nonionic contrast agents, there is an increased need to inform low-risk patients
4.
5. 6. 7.
8.
9.
use
university-affil-
10.
Spring DB, Atkin JR. Margulis AR. Informed consent for intravenous contrast-enhanced radiology: a national survey of practice and opinion. Radiology 1984; 152:609-613. Barloon TJ, Brown RC, Berbaum KS. Current status of adult uroradiology: a survey of members of the Society of Uroradiology. AJR 1990; 154:301-304. Sprung CL, Winick BJ. Informed consent in theory and practice: legal and medical perspectlves on the informed consent doctrine and proposed reconceptualization. Crit Care Med 19g9; 17:1346-134. Bettmann MA, Holzer JF, Trombly ST. Risk management issues related to the use of contrast agents. Radiology 1990; 175:629-631. Lalli AF. Urographic contrast media reactions and anxiety. Radiology 1974; 112:267-271. Bush WH. Informed consent for contrast media. AJR 1989; 152:867-869. Spring DB, Winfield AC, Friedland GW, Shuman WP, Preger L. Written informed consent for IV contrast-enhanced radiography: patients attitudes and common limitations. AJR 1988; 151:1243-1245. Jacobsen PD, Rosenquist CJ. The introduction of low osmolar contrast agents in radiology: medical, economic, legal and public po1icy issues. JAMA 1988; 260:1586-1592. Reuter SR. An overview of informed consent for radiologists. AJR 1987; 148:219-227. Miller CJ. Informed consent. II. JAMA 1980; 244:2347.
iated
and associated with larger practice groups and/or larger hospitals helps explain the disagreement between our results and those of previous surveys. In
July
1992
