AANA Journal/April 2006/Vol. 74, No. 2
tion of PONV often involves the use of antiemetic
agents that work specifically on receptors in an area of
the brain called the chemoreceptor trigger zone. Stud-
ies have shown that stimulation at one or more of the
receptors found in this region will stimulate the vomit-
ing reflex; therefore, most pharmacological regimens
include medications that block one of these receptor
sites.1,2,10Of the multitude of antiemetic agents avail-
able for use in clinical anesthesia practice, the most
common agents used are ondansetron, droperidol,
metoclopramide, dexamethasone, and scopolamine. Of
these, many clinicians prefer ondansetron to prevent
and treat PONV , especially for patients who are highly
susceptible to PONV.7-10
Ondansetron was the first serotonin receptor antag-
onist approved for the prevention and treatment of
Specific risk factors place patients at greater risk for post-
operative nausea and vomiting (PONV). Routinely, these
patients are treated prophylactically with intravenous (IV)
ondansetron or transdermal (TD) scopolamine. No study
has examined what effect using a combination of these pro-
phylactic treatments would have on the incidence of PONV
in a group of high-risk patients.
A total of 56 patients at high risk for PONV were treated
prophylactically with IV ondansetron and randomized to
receive a TD scopolamine patch or placebo. Demographics,
incidence, and severity of PONV and side effects and
antiemetic requirements were measured. Nausea was meas-
ured using a 0 to 10 verbal numeric rating scale. Descriptive
risk for the occurrence of PONV. These risk factors
include nonsmoker, female gender, history of PONV ,
history of motion sickness, and undergoing general
anesthesia for longer than 60 minutes. In fact, it has
been noted that the incidence of PONV increases expo-
nentially from 16% when 1 risk factor is present to as
high as 87% when all 5 risk factors are present.3-5
Therefore, it has become routine in many clinical anes-
thesia practices to specifically identify patients with
these risk factors so that an aggressive management
plan can be implemented to prevent PONV.6-10Preven-
and inferential statistics were used for analysis.
No difference in demographics or the incidence of side
effects was noted between groups. Patients in the scopo-
lamine group had a lower incidence of PONV (P = .043),
longer time to first reported nausea (P = .044), longer time
to first episode of emesis (P = .031), and decreased supple-
mental antiemetic requirements (P = .016) compared with
the placebo group.
Based on this study, we recommend using a combination
of TD scopolamine and IV ondansetron to prevent PONV in
patients identified as high risk for PONV.
Key words: Ondansetron, postoperative nausea and vomit-
ing, prevention, scopolamine.
The effect of transdermal scopolamine on the
incidence and severity of postoperative
nausea and vomiting in a group of high-risk
patients given prophylactic intravenous
LCDR Shari Jones, CRNA, MSN, NC, USN
San Diego, California
LTRobert Strobl, CRNA, MSN, NC, USN
LCDR Dan Crosby, CRNA, MSN, NC, USN
USS Ronald Reagan, CVN-77
CDR Joseph F. Burkard, CRNA, DNSc, NC, USN
San Diego, California
CDR John Maye, CRNA, PhD, NC, USN
CAPTJoseph E. Pellegrini, CRNA, DNSc, NC, USN
ostoperative nausea and vomiting (PONV)
is one of the most frequent and distressing
complaints reported by patients following
surgery.1,2Certain risk factors have been
identified that place patients at considerable
128 AANA Journal/April 2006/Vol. 74, No. 2 www.aana.com/members/journal/
PONV in oral and intravenous (IV) forms and has
been designated as the first-line treatment regimen for
nausea and vomiting.11,12Studies have shown that a 4-
mg dose is very efficacious in the prevention of early
PONV but less efficacious in the prevention of PONV
beyond an interval of 2 hours following surgery.12
Scopolamine, another medication that can be admin-
istered prophylactically, offers several advantages over
traditional antiemetic agents. These advantages include
transdermal (TD) patch application, known efficacy in
the treatment and prevention of PONV in patients with
a history of motion sickness, and a duration of action of
approximately 72 hours. Because of these factors, TD
scopolamine seems to be an ideal prophylactic medica-
tion for patients at high risk for PONV. However, there
are some problems with TD scopolamine. Foremost, TD
scopolamine often has to be placed on the patient sev-
eral hours before surgery to achieve clinical effective-
ness, and studies have shown that it often will not pre-
vent the occurrence of PONV in the immediate
postoperative period. There also is some evidence to
indicate that TD scopolamine may not be efficacious in
the prevention of PONV for all types of surgical proce-
dures and may be better suited when used in combina-
tion with another antiemetic agent.13
Using 2 known antiemetic agents is becoming more
common in the clinical setting. This approach, called
the multimodal approach, has been shown to be highly
effective in the treatment and prevention of PONV for
a wide variety of surgical procedures.14-16Using the
multimodal approach to prevent and treat PONV
makes sense because by using more than one agent,
one can take advantage of the unique pharmacokinet-
ics and dynamics of each agent. More specifically,
using agents that work at various areas of the chemore-
ceptor trigger zone that have different onsets and dura-
tion of actions, provides the patient with a greater
degree of prophylaxis and treatment. To date, no study
has evaluated how effective the prophylactic adminis-
tration of IV ondansetron and TD scopolamine would
be in the prevention of PONV in a group of patients
identified as highly susceptible to PONV.
The purpose of this study was to determine if using
a combination of TD scopolamine and IV ondansetron
would be more efficacious in preventing PONV in a
group of patients at high risk for PONV compared
with a similar group given IV ondansetron alone.
After approval by the institutional review board, this
randomized, double-blind, placebo-controlled, pro-
spective study was performed in groups of high- risk
patients scheduled to receive general anesthesia of
longer than 1 hour. Only ASA physical status I and II
patients who were 18 years or older and reported at
least 3 of the 5 risk factors were considered for inclu-
sion. Determination of risk factors was assessed dur-
ing the preoperative screening process. Subjects were
excluded if they reported a recent upper respiratory
tract infection; the recent use of serotonin antagonists,
scopolamine, antiemetic drugs, or psychoactive drugs;
hypersensitivity to serotonin antagonists or scopo-
lamine; or being pregnant.
After inclusion criteria were met, informed consent
was obtained and subjects were randomized into a
control (group 1, received a placebo patch) or scopo-
lamine (group 2, received a scopolamine patch) group
via a computer-generated randomization process. The
placebo patches were supplied by Novartis (Basel,
Switzerland) and contained no active ingredients.
They were identical in appearance to the TD scopo-
lamine patches that were purchased for this study and
were not in the hospital formulary. The scopolamine
patches were designed to deliver 1.5 mg of scopo-
lamine in a time-release manner during 72 hours. The
pharmacy generated a random number table and
placed the patches in dark plastic bags numbered 1 to
60. All of the patches then were maintained in a
secure location by the investigators until subjects
were consented and enrolled in the study. The patches
were numbered individually before being placed on
subjects by the investigators. Subjects and investiga-
tors were unaware of which patch was being placed
until the completion of data collection.
Patients were screened using either of two methods.
The first method consisted of distributing a question-
naire to all surgical patients through the individual
surgical clinics and the preoperative clinic. Patients
who were identified to be at high risk and scheduled
for procedures requiring general anesthesia for longer
than 60 minutes were contacted for participation. In
addition, a second method that involved scanning the
next days’ surgical schedule for procedures requiring
general anesthesia for longer than 60 minutes was
used to help identify patients. These patients’ preoper-
ative charts were reviewed to determine whether they
had any of the other risk factors. Subjects who had 3
or more of the 5 risk factors were contacted by tele-
phone the night before surgery to determine if they
would be interested in study participation.
On the day of surgery, after informed consent was
obtained, subjects were admitted to the preoperative
hold area. All subjects were assigned a subject number
and randomized into group 1 or group 2. The phar-
macy department kept a log that identified the group
for each subject. Neither the investigators nor the sub-
jects were informed of group assignment until the
conclusion of data collection.
AANA Journal/April 2006/Vol. 74, No. 2
Before placement of the patch, nausea was meas-
ured using an 11-point, 0 to 10 verbal numeric rating
scale (VNRS) in which a score of “0” indicated “no
nausea” and a score of “10” indicated “the worst nau-
sea imaginable” to determine a baseline. The patch
then was placed behind one of the subject’s ears. Ide-
ally, this occurred at least 2 hours before induction of
general anesthesia; however, due to operating room
scheduling, the first contact with the majority of sub-
jects was approximately 40 minutes before induction.
An IV infusion of lactated Ringer’s was started, and
subjects were premedicated with 0 to 5 mg of mida-
zolam and 0 to 150 µg of fentanyl.
Subjects then were transported to the operating
room where standard monitors, including a noninva-
sive blood pressure monitoring device, an electrocar-
diogram, and a pulse oximeter were placed. General
anesthesia was induced per provider preference and
maintained with inhalation agent of choice and less
than 50% nitrous oxide. At 30 minutes before emer-
gence, each subject received 4 mg of IV ondansetron.
Reversal of neuromuscular blockade was left to the
discretion of individual providers. After extubation,
subjects were transported to the postanesthesia care
unit (PACU) with oxygen supplementation.
Following transport to the PACU, nausea was
measured using the 0 to 10 VNRS on arrival, every 15
minutes while in the PACU, and again on arrival and
discharge in same-day surgery unit or inpatient ward
and at a complaint of nausea for 72 hours following
surgery. All subjects were asked to keep the patch in
place for at least 72 hours following surgery and were
given instructions concerning patch care following
discharge from the hospital. All subjects were asked to
keep a log of the time and severity of nausea (using
the 0-10 VNRS) for 72 hours following surgery. They
were instructed that they would be receiving a follow-
up phone call from one of the investigators 72 hours
following surgery to obtain information recorded in
their logs. In addition, all subjects were told that they
would be asked to rate their overall satisfaction with
their quality of nausea relief at the 72-hour follow-up
phone interview. Satisfaction was measured using a 5-
point Likert scale that used the follow grading criteria:
(1) dissatisfied, (2) somewhat dissatisfied, (3) some-
what satisfied, (4) satisfied, and (5) very satisfied.
Inferential and descriptive statistics were used for
data analysis. Descriptive statistics were used for demo-
graphic variables. Satisfaction scores were analyzed
using a Mann-Whitney U test. A Pearson correlation
was used to predict overall level of satisfaction in sub-
jects who complained of nausea postoperatively, con-
trolling for group assignment. A Student t test was used
to analyze VNRS scores, postoperative analgesic require-
ments, and antiemetic requirements between groups. A
P value of less than .05 was considered significant.
Before implementation of the study, a power analysis
was performed using an a of .05 and a power of 0.8. It
was determined that a sample size of 27 per group
would produce an estimated 20% difference in PONV
scores between the groups. Factoring an attrition rate of
10% (3 subjects per group), the final sample size
required was 60 subjects, or 30 subjects per group.
We enrolled 60 subjects in this double-blind, random-
ized, placebo-controlled study. A total of 4 subjects
were disenrolled, 1 for inadvertent removal of the
patch, 1 for incomplete data collection, and 2 for
intentional removal of patches secondary to headaches
(ondansetron only group). This left a total of 56 sub-
jects with data for analysis (28 in each group). No dif-
ference was noted in gender, age, weight, height, eth-
nic background, or number of risk factors present
between groups (Table 1). No significant differences in
preoperative, intraoperative, or postoperative analgesic
or anxiolytic requirements; volatile agent require-
ments; or need for reversal from neuromuscular block-
ade were noted between groups.
There was no difference found between the groups
in the mean time from patch placement and time to
induction or from patch placement and arrival in the
PACU (Table 2). No difference in incidence of side
effects was noted between groups, but it was noted
(n = 28)
(n = 28)
No. of risk factors present
Table 1. Variables associated with demographics*
* No significant differences were noted in demographic variables or the
number of risk factors for postoperative nausea and vomiting between the
placebo and scopolamine groups.
130AANA Journal/April 2006/Vol. 74, No. 2 www.aana.com/members/journal/
that a higher incidence of side effects occurred in
group 1 than in group 2 (Table 3).
When the overall incidence of nausea was analyzed
for the first 24 hours following surgery, it was noted
that 17 (61%) of subjects in group 2 reported “no nau-
sea” compared with only 7 (25%) of subjects in group
1 (P = .007) (Figure 1). Initial PACU antiemetic treat-
ment was required for 8 subjects in group 2 and 19
subjects in group 1 (P = .007) (Figure 2). Analysis of
the second treatment for complaints of PACU nausea
revealed that only 1 subject in group 2 required treat-
ment compared with 8 subjects in group 1 (P = .025)
(see Figure 2).
The mean ± SD time to first request for nausea
treatment was longer in group 2 (361 ± 171 minutes)
than for group 1 (259 ± 108 minutes) (P = .044). The
incidence of emesis also was lower in group 2 (6
episodes) than in group 1 (12 episodes), but the dif-
ference did not achieve statistical significance (P =
.152). However, when the time to first emetic event
was analyzed, a significant difference was noted. The
mean ± SD time for the initial episode of emesis was
498 ± 102 minutes for group 2 vs 324 ± 129 minutes
for the control group (P = .031) (Figure 3). In addi-
tion, 1 patient in group 2 reported an episode of
PONV following discharge from the hospital com-
pared with patients in group 1 (P = .043). The use of
reversal agent was not correlated with any nausea or
Overall patient satisfaction scores between groups
were similar with the median level of satisfaction
being 4 in group 1 compared with 5 in group 2. How-
ever, when patients who complained of nausea were
isolated, the satisfaction scores were significantly
lower in group 1 (P = .006). There was no statistical
significance between the groups when analyzing
VNRS scores; however, the scores tended to be lower
in group 2 compared with group 1.
Postoperative nausea and vomiting is multifactorial in
etiology and has given rise to investigations proposing
prophylactic measures to minimize these symptoms.
Factors contributing to PONV can be categorized into
3 groups, including patient-related factors, surgery-
related factors, and anesthesia-related factors. In our
study, we focused on patient-related factors that
placed patients at an increased risk of developing
PONV. Koivuranta et al5proposed a simple method of
classifying patients based on 5 patient-related criteria.
Did the patient experience nausea?
Figure 1. Overall incidence of nausea within 24 hours
of surgery (PACU, SDSU, ward, home)
When overall incidence of nausea was analyzed for the
first 24 hours following surgery, it was noted that 17
(61%) of subjects in the scopolamine group reported
“no nausea” as compared with only 7 (25%) of the
subjects in the placebo group (P = .007).
PACU indicates postanesthesia care unit; and SDSU, same-day surgery unit.
(n = 28)
(n = 28)
Time from patch place-
ment to induction of
Time from patch place
ment to arrival in the
45.6 ± 45 57.8 ± 41.3
213.4 ± 121.7 251.3 ± 89.3
Table 2. Patch placement times*
* No significant differences were noted between groups in relation to mean ±
SD time from patch placement to induction of anesthesia (P = .263) or to
postanesthesia care unit (PACU) arrival (P = .204).
(n = 28)
(n = 28)
Table 3. Side effects experienced by group*
* No significant differences were noted between groups in relation to
occurrence of side effects (P > .05), although a higher incidence was noted in
the placebo group than in the scopolamine group.
AANA Journal/April 2006/Vol. 74, No. 2
Using this simplified method, patients meeting 3 of 5
risk factors would have an incidence of PONV of
54%.5We suggest that the incidence of PONV at this
percentage would justify prophylactic treatment.
During the past several decades, there have been
numerous research studies supporting the effective-
ness of reducing PONV with ondansetron as a single
agent and in combination with other agents, includ-
ing metoclopramide, droperidol, and dexametha-
sone.7-12,14,17In a study by Sadhasivam et al,8ondanse-
tron used as a single agent decreased PONV from 81%
to 33% compared with a placebo.
In our study, the control subjects received
ondansetron as a single agent and reported a 75% inci-
dence of PONV. In analysis of risk factors present, it
was noted that approximately 50% of the sample in
both groups had 4 or 5 of the risk factors present,
placing them at a higher risk for PONV. Koivuranta et
al5reported that the risk of PONV increases exponen-
tially based on the number of risk factors present
(67% with 4 risk factors and 87% with 5 risk factors);
therefore, it was not surprising that we had a higher
incidence of PONV for the entire sample than the pro-
jected 54% when only 3 risk factors are present.
What was surprising was that we still had such a
high incidence of PONV despite all subjects receiving
a prophylactic dose of 4 mg of ondansetron. The high
rate could have been attributed to study design
(allowing for patients to receive 50% nitrous oxide or
not controlling for surgical procedures). Perhaps not
isolating the patient populations to a specific surgical
procedure or allowing the use of nitrous oxide may
have decreased the degree of PONV prophylaxis from
the ondansetron. A repeat of this study in which these
variables are controlled is needed to determine
whether these variables were possible causative fac-
tors attributing to the high degree of PONV found in
There also have been a number of studies support-
ing that TD scopolamine is safe and effective for the
treatment and prevention of PONV.18-20When scopo-
lamine was compared with a placebo in women who
received epidural morphine after cesarean section,
nausea and vomiting was reduced from 50% to 13%
during the first 24 hours postoperatively.18Bailey et
al21showed that scopolamine reduced nausea and
vomiting from 62% to 37% compared with a placebo
after laparoscopic surgery. Our study did not compare
scopolamine as a single agent; however, this might be
included in future investigations.
Our study combined scopolamine and ondansetron
and tested 56 patients who were classified as high risk
for PONV. We found that patients who received a com-
bination of TD scopolamine and ondansetron overall
did better than those receiving ondansetron alone.
Pueyo et al22showed that combination therapy reduced
PONV from 72% to 8%. We found that the combination
of ondansetron and scopolamine reduced PONV from
Figure 2. PACU antiemetic treatment requirements
Initial postanesthesia care unit (PACU) antiemetic treat-
ment was required for 8 subjects in the scopolamine
group and 19 subjects in the placebo group (P = .007).
When second treatment for complaints of PACU nausea
was analyzed, it was noted that only 1 subject in the
scopolamine group required treatment compared with 8
subjects in the placebo group (P = .025).
Mean ± SD time (min)
Time to nausea event
Time to emetic event
Figure 3. Time from patch placement to nausea event
When the time to first emetic event was analyzed, a
significant difference was noted. The mean ± SD time
for the initial episode of emesis was 498 ± 102
minutes for the scopolamine group vs 324 ± 129
minutes for the control group (P = .043).
132 AANA Journal/April 2006/Vol. 74, No. 2www.aana.com/members/journal/ Download full-text
75% to 39%. The difference could be attributed to the
differences in patient population. Our study included
men, and we did not control for surgical procedure,
whereas Pueyo et al22limited their population to
women undergoing intra-abdominal surgery.
One of the dangers of prophylactic treatment of
PONV is the potential of increased side effects. In a
meta-analysis of antiemetic use performed by Domino
et al,7there were no significant differences for any side
effects, but ondansetron had an increased risk for
headache compared with droperidol. Our study find-
ings agree with these results. We monitored both
groups for side effects normally attributed to scopo-
lamine and ondansetron, including itching, headache,
and dry mouth. The most frequently reported side
effect was headache, which has been attributed to
ondansetron.7Two of our patients experienced
headaches early in the recovery period and removed
their patches before 72 hours.
Ondansetron continues to be a popular choice in
the treatment and prevention of PONV. Transdermal
scopolamine is becoming a popular choice in the
treatment of motion sickness. Our study suggests that
the combination of ondansetron and scopolamine
produced a better outcome in the prevention and suc-
cessful treatment of PONV. Future studies using
scopolamine along with other antiemetics affecting
alternative receptor pathways could prove even more
effective in the reduction of PONV.
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Saez A. Combination of ondansetron and droperidol in the prophy-
laxis of postoperative nausea and vomiting. Anesth Analg. 1996;
LCDR Shari Jones, CRNA, MSN, NC, USN, is a staff nurse anesthetist
of the Naval Medical Center San Diego, Calif.
LT Robert Strobl, CRNA, MSN, NC, USN, is a staff nurse anesthetist
at Naval Hospital Lemore, Calif.
LCDR Daniel Crosby, CRNA, MSN, NC, USN, is a staff nurse anes-
thetist stationed on board the USS Ronald Reagan, CVN-77.
CDR Joseph F . Burkard, CRNA, DNSc, NC, USN, is a clinical
research coordinator for the Navy Nurse Corps Anesthesia Program,
San Diego, Calif. Email: JFBurkard@nmcsd.med.navy.mil
CDR John Maye, CRNA, PhD, NC, USN, is the clinical research
coordinator for the Naval Postgraduate Dental School, Bethesda, Md.
CAPT Joseph E. Pellegrini, CRNA, DNSc, NC, USN, is the director
of clinical research for the Navy Nurse Corps Anesthesia Program,
The Chief, Bureau of Medicine and Surgery, Navy Department, Wash-
ington, DC, Clinical Investigation Program sponsored this report # S-
02-099, as required by NSHSBETHINST 6000.41A.
The views expressed in this article are those of the authors and do not
reflect the official policy or position of the Department of the Navy,
Department of Defense, or the United States Government.