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ORIGINAL ARTICLES
A Prospective Randomized Study of the
Effectiveness of Aromatherapy for Relief
of Postoperative Nausea and Vomiting
Nancy S. Hodge, RN, MSN, BSN, ACNS-BC, Mary S. McCarthy, RN, PhD, MN, BSN,
Roslyn M. Pierce, BA
Introduction: Postoperative nausea and vomiting (PONV) is a major con-
cern for patients having surgery under general anesthesia as it causes
subjective distress along with increased complications and delays in dis-
charge from the hospital. Aromatherapy represents a complementary and
alternative therapy for the management of PONV.
Purpose: The objective of this study was to compare the effectiveness ofaro-
matherapy (QueaseEase, Soothing Scents, Inc, Enterprise, AL) versus an
unscented inhalant in relieving PONV.
Methods: One hundred twenty-one patients with postoperative nausea
were randomized into a treatment group receiving an aromatic inhaler
and a control group receiving a placebo inhaler to evaluate the effective-
ness of aromatherapy.
Findings: Initial and follow-up nausea assessment scores in both treatment
and placebo groups decreased significantly (P,.01), and there was a signif-
icant difference between the two groups (P5.03). Perceived effectiveness of
aromatherapy was significantly higher in the treatment group (P,.001).
Conclusions: Aromatherapy was favorably received by most patients and
represents an effective treatment option for postoperative nausea.
Keywords: aromatherapy, postoperative nausea, complementary ther-
apy, CAM, research, perianesthesia nursing.
Published by Elsevier Inc. on behalf of the American Society of
PeriAnesthesia Nurses
POSTOPERATIVE NAUSEA AND VOMITING
(PONV) is a major concern of providers for pa-
tients having surgery under general anesthesia.
PONV is associated with subjective distress as
well as increased complications and delays in dis-
charge from the hospital. The consequences of
prolonged nausea and vomiting significantly affect
postoperative morbidity and include dehydration,
electrolyte disturbances, aspiration, and even
wound dehiscence.
1
Aromatherapy represents
a complementary and alternative therapy to the
management of PONV.
Nancy S. Hodge, RN, MSN, BSN, ACNS-BC, is a Medical-Surgi-
cal Clinical Nurse Specialist, Center for Nursing Science &
Clinical Inquiry, Madigan Army Medical Center, Tacoma,
WA; Mary S. McCarthy, RN, PhD, MN, BSN, is a Senior Nurse Sci-
entist, Center for Nursing Science & Clinical Inquiry, Madigan
Army Medical Center, Tacoma, WA; and Roslyn M. Pierce, BA,
is a Research Assistant, Center for Nursing Science & Clinical
Inquiry, Madigan Army Medical Center, Tacoma, WA.
The views expressed in this article are those of the authors
and do not reflect the official policy of the Department of the
Army, the Department of Defense, or the US Government. The
investigators have adhered to the policies for protection of hu-
man subjects as prescribed in 45 CFR 46.
Conflict of interest: QueaseEase and placebos were pro-
vided free of charge.
Address correspondence to Nancy S. Hodge, 6908 65th Ave-
nue West, Lakewood, WA 98499; e-mail address: nancy.s.
hodge@us.army.mil.
Published by Elsevier Inc. on behalf of the American Society
of PeriAnesthesia Nurses
1089-9472/$36.00
http://dx.doi.org/10.1016/j.jopan.2012.12.004
Journal of PeriAnesthesia Nursing, Vol 29, No 1 (Februar y), 2014: pp 5-11 5
Literature Review
Depending on the number of risk factors a patient
has for PONV, the incidence ranges anywhere from
10% to 87%. This is not surprising, given that dif-
ferent surgical populations, procedures, and anes-
thetic methods influence PONV.
2,3
Most patients
and surgeons believe PONV is caused by the
anesthetic agent used for the procedure.
4
How-
ever, there is literature to support a significant re-
duction in PONV with the introduction of
halogenated inhalational agents in the 1960s.
5
The problem of PONV continues to persist unfor-
tunately; the mechanisms for it are numerous and
the causative pathways are not well elucidated.
In 1997, Koivuranta et al described PONV risk fac-
tors in the adult surgical population. These risk fac-
tors included female gender, non-smoking status,
history of PONV, history of motion sickness, and
duration of surgery greater than 60 minutes.
6
In
1999, Apfel et al identified female gender, non-
smoking status, history of PONV or motion sick-
ness, and postoperative opioids as the four most
significant predictors of PONV. The propensity
for the development of PONV is cumulative with
each additional risk factor adding to the risk of oc-
currence. For example, with one risk factor the
PONV risk is 10%, but if four risk factors are re-
ported, the PONV risk rises to 80%.
7
Current drug therapies used to treat PONV such as
dopamine receptor antagonists (eg, metoclopra-
mide) and butyrophenones (eg, droperidol) have
occasional undesirable side effects that include ex-
cessive sedation, hypotension, dry mouth, extrapy-
ramidal reactions, and limited dosing abilities.
8
Some drug combinations may have additional ad-
verse effects such as headache, dizziness, and
drowsiness. The negative outcomes of PONV may
require additional medications, more attention
from nurses and physicians, and an extended hos-
pital length of stay, all of which increase the cost
of related health care.
Alternative treatments are now being used to help
control PONV with early favorable results. These
treatments include nausea relief bands (pressure
point or electrical stimulation), intraoperative
high concentration oxygen administration, acu-
pressure, acupuncture, music, and aromatherapy.
Aromatherapy, a complementary therapy, is de-
fined as ‘‘treatment using scents.’’
9
It is a relatively
new area of research for PONV. These non-
pharmacologic modalities are appealing to many
patients and assist in the emotional and physical
healing that enhances one’s overall well-being
and quality of life.
1
Smiler and Srock found that
aromatherapy with isopropyl alcohol effectively
treated the nausea caused by the motion patients
experience while being transported on a gurney.
10
Wang et al found that isopropyl alcohol was more
effective than placebo as the initial treatment for
nausea in children, although the effect was limited
to less than 1 hour.
11
Merritt et al were unable to
demonstrate a beneficial effect of isopropyl alco-
hol inhalation in patients with PONV; their study
had no control group and a small sample size.
12
A randomized, double blind study by Anderson
and Gross enrolled subjects experiencing PONV
to receive aromatherapy with isopropyl alcohol,
oil of peppermint, or placebo (saline).
13
The va-
pors were inhaled from scented gauze pads held
directly beneath the nose. Subjects were instructed
to exhale slowly through their mouth. They rated
their nausea on a visual analog scale at 2 and 5 min-
utes after the inhalation. Overall nausea scores
decreased from 60.6 64.3 mm before aromather-
apy to 43.1 64.9 mm (P,.005) at 2 minutes
and to 28.0 64.6 mm (P,.0001) at 5 minutes after
aromatherapy. While decreased, nausea scores did
not differ between groups. Only 52% of the sub-
jects required additional antiemetic therapy during
their post-anesthesia care unit (PACU) stay. Overall
patient satisfaction with postoperative nausea
management was 86.9 64.1 mm and was indepen-
dent of treatment group. The researchers con-
cluded that aromatherapy effectively reduced
perceived severity of PONV and that the ben eficial
effect may be related to the controlled breathing
patterns that subjects were instructed on during
the study. This study did provide support for iso-
propyl alcohol as well as herbal inhalations. No
safety concerns for subjects were identified.
Aromatherapy formulations that have been popu-
lar alone or as adjuncts to conventional treatments
include peppermint oil ingestion for morning sick-
ness, dyspepsia, and other gastrointestinal com-
plaints; peppermint oil vapor for the reduction of
postoperative nausea in surgical gynecology pa-
tients; and ginger as a powder, candy, or oil to
reduce the incidence of 24-hour PONV among
6HODGE, MCCARTHY, AND PIERCE
patients undergoing gynecologic and lower ex-
tremity surgeries.
14
Only one study was found
that described the use of lavender oil aromather-
apy for postoperative pain; the treatment group
pain scores were not significantly different than
the control group, but overall satisfaction with
pain control was higher in the group receiving lav-
ender aromatherapy.
15
There is a paucity of research using aromatherapy
interventions for PONV, with few new studies in
the last decade. A recent review published in The
Cochrane Library examined six randomized con-
trolled trials and three clinical controlled trials to
establish the effectiveness of aromatherapy on the
severity and duration of PONV in a total of 402
participants. The conclusion of the reviewers was
that isopropyl alcohol was more effective than sa-
line placebo for reducing PONV but less effective
than standard anti-emetic drugs. Patient satisfaction
was not different between groups receiving aroma-
therapy or standard therapy.
16
Purpose
The purpose of this study was to compare the
effectiveness of aromatherapy delivered by a hand-
held inhaler (QueaseEase; Soothing Scents, Inc, En-
terprise, AL) to an unscented inhaler for reducing
PONV in patients who were admitted to a surgical
unit for at least 24 hours postoperatively.
Design
A prospective randomized two-group design was
used with the treatment group receiving an aromatic
inhaler and the control group receiving a placebo
inhaler.
Method
This study was conducted in a 250-bed military
medical center in the Pacific Northwest. Human
subjects approval was granted by the hospital’s In-
stitutional Review Board before initiating the
study. Study inclusion criteria were adult surgical
patients with planned admission to the inpatient
unit for postoperative care. Patients with an allergy
to lavender, peppermint, spearmint, or ginger
were excluded. Patients were recruited from
the Pre-Admission Surgery Center and enrolled 1
to 5 days before surgery with documentation of in-
formed consent. Study procedures were initiated
with the first complaint of nausea on the postoper-
ative inpatient unit. Because of the reported asso-
ciation between tobacco use and decreased
PONV, we decided to ask patients about nicotine
use and compare rates of PONV between users
and non-users.
A self-administered scented QueaseEase inhaler
or an unscented identical inhaler was used as an
immediate treatment for nausea and was followed
by prescribed antiemetic therapy if ineffective.
QueaseEase is an over-the-counter aromatherapy
product formulated as an aromatic inhaler con-
taining a proprietary blend of lavender, pepper-
mint,ginger,andspearmintoils.Itwas
developed by a nurse who intended it to be
used for morning sickness, motion sickness, and
nausea related to chemotherapy, and postopera-
tive recovery.
17
The inhaler is a portable, handheld
device that can be kept at the patient’s bedside for
immediate use. The patient is instructed to remove
the cap, hold the container under the nose, and take
a few deep breaths. The patient can use it as often as
needed and the product is effective for up to
6 months if the cap is replaced tightly after each
use. There are no known or reported risks to this
therapy except allergy to any of the oils used in
the inhaler.
Patients completed two 10-point Likert-type
scales (0 5none, 10 5worst possible) rating
nausea at baseline and after 3 minutes, as well
as questionnaires addressing satisfaction with
nausea treatment and perceived effectiveness of
aromatherapy. In addition, 10% of patients were
asked to participate in an individual brief inter-
view with one of the research team members to
discuss attitudes about aromatherapy. The study
included the period of time from the first postop-
erative episode of nausea until 24 hours later,
with the brief interview planned for 10% of pa-
tients at 24 hours or upon discharge, whichever
came first. Using previous studies involving aro-
matherapy, the following considerations were in-
cluded in the power analysis: allowing for an
attrition rate of 10%, alpha 50.05 and a standard
deviation on questionnaire responses of 0.5 to 1,
and a beginning sample size of 60 subjects in
each group was required to determine if a statisti-
cally significant difference between groups ex-
isted.
PONV AROMATHERAPY STUDY 7
Analysis
Patients evaluated and ranked their nausea on a de-
scriptive ordinal scale with 0 5‘‘no nausea’’ and
10 5‘‘the worst nausea ever.’’ Unpaired ttests
were used to compare scores at baseline and at
the 3-minute post-aromatherapy interval between
groups while paired ttests were used for within
group comparisons at the two time points. Inde-
pendent ttests were used to compare scores on
the patient satisfaction question with 0 5‘‘com-
pletely dissatisfied’’ and 10 5‘‘completely
satisfied’’ and the perceived effectiveness of aro-
matherapy question with 0 5‘‘completely ineffec-
tive’’ and 10 5‘‘completely effective.’’ Statistical
analyses were performed using SPSS, v14.0 (IBM,
Armonk, NY) with significance set at P,.05.
Findings
Of 339 enrolled patients, 121 patients experi-
enced PONV. Ninety-four patients received an in-
haler device; 54 received the treatment inhaler
and 40 received the placebo inhaler. Twenty-
seven patients were not offered the inhaler for var-
ious reasons such as the nurse did not realize the
patient was enrolled in the study before giving
the intravenous antiemetic, had not received train-
ing for carrying out the protocol, or felt he/she was
too busy to administer the protocol. One patient
chose not to use the inhaler when nauseated and
another vomited before the inhaler could be ad-
ministered. Demographic data including gender,
age, and tobacco use are illustrated in Table 1.A
change score was computed for the initial and
follow-up nausea assessment scores. Nausea scores
in both the treatment group and the placebo group
decreased significantly, P,.01 respectively, and
there was a significant difference between the
two groups, P5.03 (Figure 1). Perceived effective-
ness of aromatherapy was examined between
groups. The scores for patients in the treatment
group (M 55.72 63.26) were higher than in the
placebo group (M 52.72 63.12). This 3-point dif-
ference between means was statistically significant
(95% confidence interval 51.60 to 4.39 points;
two-tailed Student ttest, t54.27; df 584;
P,.001). Independent sample ttests showed no
difference between groups on their ratings of over-
all satisfaction with nausea management; both
groups rated satisfaction between 6.8 and 7.1 on
the 0-10 Likert scale (Figure 2).
Table 1. Demographic Data
Variables
Number of Subjects
N (Total Enrolled) 5339 Percent (%) of Subjects
PONV event 121 35.7
Gender—female 220 66.5
Age $40 y 161 47.4
Tobacco use 57 17.2
Operative procedure
Cervical/lumbar discectomy/laminectomy 24 8.1
Incision and drainage 3 1.0
Laparoscopic/resectional gastric bypass/sleeve*50 17.0
Laparotomy 18 6.1
Mammoplasty*32 10.9
Neck dissection 4 1.4
Open reduction internal fixation 12 4.1
Osteotomy 9 3.0
Panninculectomy 18 6.1
Arthroplasty (knee, shoulder, other joint) 26 8.8
Thyroidectomy 8 2.7
TAH/TVH*32 10.9
Uro-gynecologic procedures 21 7.2
Other 82 24
PONV, postoperative nausea and vomiting; TAH, total abdominal hysterectomy; TVH, total vaginal hysterectomy.
*Denotes top 3 diagnoses for patients experiencing PONV.
8HODGE, MCCARTHY, AND PIERCE
Ten percent of the patients were randomly se-
lected to volunteer additional information in a brief
interview concerning their aromatherapy experi-
ence. Comments suggested that the aromatherapy
was more effective for lower levels of nausea. Sev-
eral patients who received the placebo inhaler
asked if they could have a ‘‘real’’ inhaler for their
discharge home at the end of the study period.
One patient felt the aromatherapy was more effec-
tive than the acupressure bracelets she had used
while in PACU. And one patient who had brought
his own essential oils with him to the hospital to
use in the event of PONV said he was pleased be-
cause he did not even need to use his own oils.
While generally pleasing to patients, one patient
did say the fragrance made the nausea worse.
Discussion
Evidence-based nursing interventions are desper-
ately needed for surgical patients experiencing
PONV. When looking to the literature to uncover
evidence for a nursing policy for postoperative
care, the research team noted the lack of current
and relevant therapies for short-stay surgical pa-
tients. This led to the current research study,
which resonated with all staff nurses in the
medical-surgical unit. Having bedside nurses as
partners, actively engaged in the project, led to
a greater appreciation for evidence-based practice
as well as teamwork to best meet the needs of the
postoperative patient.
This study demonstrated that surgical patients in
this hospital are in favor of using aromatherapy
as a first-line approach to PONV. Patients fre-
quently commented that the lack of effectiveness
and negative side effects of antiemetics were major
concerns for them, especially those who re-
counted past experiences with PONV. Patients
who were tobacco users did indeed have a lower
rate of PONV, which is congruent with the current
literature. The lower rate in smokers has been at-
tributed to smoking-induced changes in the senses
of taste and smell, but the decreased incidence of
PONV among smokers actually results from the
chemicals in cigarette smoke affecting liver
enzyme production, which, in turn, increases me-
tabolism of several anesthesia drugs.
18
Further ex-
ploration is warranted as nicotine patches have
been unable to produce the same results.
19
The
overall success of the aromatherapy and the posi-
tive experience for staff nurses led to rapid ap-
proval of the QueaseEase product as a standard
item in our Omnicell supply system on all inpatient
units. The adoption of this product is widely
known in the institution; other inpatient and out-
patient areas frequently ask how to order the
item. The study results, and the proper indications
for use of the product, are mentioned at every new
employee nursing orientation class.
Limitations
The study results are limited to the experience in
a single institution with the only product of its
Figure 1. Mean difference initial and follow-up
nausea scores.
Figure 2. Mean difference satisfaction overall and
perceived effectiveness.
PONV AROMATHERAPY STUDY 9
kind on the market at the time. The research team
was comprised strictly of volunteers and subject
accrual was somewhat dependent on the availabil-
ity of the team on any given day. However, there
were no attempts to seek out a specific population
and the results demonstrate that patients under-
went a wide range of surgical procedures. There
were more female volunteers, but this is a reflec-
tion of the high number of gynecologic proce-
dures performed on most days in this facility. The
intervention related to the study involved only
a 3-minute interval of time; the first experience
of nausea described by the patient evaluated on
notification of the nurse and 3 minutes following
the use of the inhaler brought to the bedside.
Many factors could impact this experience and
the response to the inhaler, to include pain, an al-
tered level of consciousness, or other lingering
aromas from anesthetic agents, blood, and so on.
Although patients had orders for intravenous or
oral antiemetic medication, there was no attempt
to collect information regarding use and effective-
ness of rescue medications when aromatherapy
was ineffective.
Lastly, the sample size fell short of the recommen-
ded number for enrollment according to the a pri-
ori power analysis, but statistical significance was
achieved nonetheless.
Further Research
The current interest in complementary and alter-
native therapies presents numerous opportunities
for nurses to conduct further research into uses of
aromatherapy. Additional research is needed to
evaluate aromatherapy for the nausea associated
with chemotherapy and morning sickness. Com-
parisons between modalities for nausea such as
aromatherapy and antiemetic bands, or guided
imagery, or music, would make interesting evi-
dence-based practice research activities. Such in-
formation may strengthen the evidence for
aromatherapy or identify adjunct modalities to en-
hance patient comfort.
Conclusion
In conclusion, the use of aromatherapy and a dedi-
cated team of nurses led to a high rate of satisfac-
tion with overall management of PONV on the
medical-surgical units. Aromatherapy was favor-
ably received by most patients and represents an
effective treatment option for postoperative nau-
sea. The nurse is not always able to respond as
promptly as desired to obtain and administer an
IV antiemetic. A device such as an aromatherapy
inhaler is immediately available to the patient
and if it does not completely relieve the nausea,
it may help the patient in the short period of
time waiting for the IV antiemetic to be adminis-
tered. This evidence-based nursing therapy is
now available to the bedside nurse in our institu-
tion to offer to patients with postoperative nausea.
Continued use and additional data will help to de-
termine if this intervention is deserving of a best
practice recommendation for bedside nurses car-
ing for postoperative patients.
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PONV AROMATHERAPY STUDY 11
