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 discharge 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 of aromatherapy (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 effectiveness of aromatherapy. Findings: Initial and follow-up nausea assessment scores in both treatment and placebo groups decreased significantly (P , .01), and there was a significant difference between the two groups (P 5 .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 therapy, 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 patients having surgery under general anesthesia. PONV is associated with subjective distress as well as increased complications and delays in discharge 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-Surgical 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 Scientist, 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 human subjects as prescribed in 45 CFR 46. Conflict of interest: QueaseEase and placebos were provided free of charge. Address correspondence to Nancy S. Hodge, 6908 65th Avenue West, Lakewood, WA 98499; e-mail address: nancy.s. [email protected]
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 (February), 2014: pp 5-11
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 different surgical populations, procedures, and anesthetic methods influence PONV.2,3 Most patients and surgeons believe PONV is caused by the anesthetic agent used for the procedure.4 However, there is literature to support a significant reduction in PONV with the introduction of halogenated inhalational agents in the 1960s.5 The problem of PONV continues to persist unfortunately; the mechanisms for it are numerous and the causative pathways are not well elucidated. In 1997, Koivuranta et al described PONV risk factors in the adult surgical population. These risk factors 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, nonsmoking status, history of PONV or motion sickness, 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 occurrence. For example, with one risk factor the PONV risk is 10%, but if four risk factors are reported, the PONV risk rises to 80%.7 Current drug therapies used to treat PONV such as dopamine receptor antagonists (eg, metoclopramide) and butyrophenones (eg, droperidol) have occasional undesirable side effects that include excessive sedation, hypotension, dry mouth, extrapyramidal reactions, and limited dosing abilities.8 Some drug combinations may have additional adverse 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 hospital 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, acupressure, acupuncture, music, and aromatherapy. Aromatherapy, a complementary therapy, is de-
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fined as ‘‘treatment using scents.’’9 It is a relatively new area of research for PONV. These nonpharmacologic 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 alcohol 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 vapors 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 minutes after the inhalation. Overall nausea scores decreased from 60.6 6 4.3 mm before aromatherapy to 43.1 6 4.9 mm (P , .005) at 2 minutes and to 28.0 6 4.6 mm (P , .0001) at 5 minutes after aromatherapy. While decreased, nausea scores did not differ between groups. Only 52% of the subjects required additional antiemetic therapy during their post-anesthesia care unit (PACU) stay. Overall patient satisfaction with postoperative nausea management was 86.9 6 4.1 mm and was independent of treatment group. The researchers concluded that aromatherapy effectively reduced perceived severity of PONV and that the beneficial effect may be related to the controlled breathing patterns that subjects were instructed on during the study. This study did provide support for isopropyl alcohol as well as herbal inhalations. No safety concerns for subjects were identified. Aromatherapy formulations that have been popular alone or as adjuncts to conventional treatments include peppermint oil ingestion for morning sickness, dyspepsia, and other gastrointestinal complaints; peppermint oil vapor for the reduction of postoperative nausea in surgical gynecology patients; and ginger as a powder, candy, or oil to reduce the incidence of 24-hour PONV among
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patients undergoing gynecologic and lower extremity surgeries.14 Only one study was found that described the use of lavender oil aromatherapy 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 lavender 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 controlled 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 saline placebo for reducing PONV but less effective than standard anti-emetic drugs. Patient satisfaction was not different between groups receiving aromatherapy or standard therapy.16
Purpose The purpose of this study was to compare the effectiveness of aromatherapy delivered by a handheld inhaler (QueaseEase; Soothing Scents, Inc, Enterprise, 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 Institutional 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 postoperative inpatient unit. Because of the reported association 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 containing a proprietary blend of lavender, peppermint, ginger, and spearmint oils. It was developed by a nurse who intended it to be used for morning sickness, motion sickness, and nausea related to chemotherapy, and postoperative 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 5 none, 10 5 worst 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 interview with one of the research team members to discuss attitudes about aromatherapy. The study included the period of time from the first postoperative episode of nausea until 24 hours later, with the brief interview planned for 10% of patients at 24 hours or upon discharge, whichever came first. Using previous studies involving aromatherapy, the following considerations were included in the power analysis: allowing for an attrition rate of 10%, alpha 5 0.05 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 statistically significant difference between groups existed.
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Table 1. Demographic Data Variables PONV event Gender—female Age $40 y Tobacco use Operative procedure Cervical/lumbar discectomy/laminectomy Incision and drainage Laparoscopic/resectional gastric bypass/sleeve* Laparotomy Mammoplasty* Neck dissection Open reduction internal fixation Osteotomy Panninculectomy Arthroplasty (knee, shoulder, other joint) Thyroidectomy TAH/TVH* Uro-gynecologic procedures Other
Number of Subjects N (Total Enrolled) 5 339
Percent (%) of Subjects
121 220 161 57
35.7 66.5 47.4 17.2
24 3 50 18 32 4 12 9 18 26 8 32 21 82
8.1 1.0 17.0 6.1 10.9 1.4 4.1 3.0 6.1 8.8 2.7 10.9 7.2 24
PONV, postoperative nausea and vomiting; TAH, total abdominal hysterectomy; TVH, total vaginal hysterectomy. *Denotes top 3 diagnoses for patients experiencing PONV.
Analysis Patients evaluated and ranked their nausea on a descriptive ordinal scale with 0 5 ‘‘no nausea’’ and 10 5 ‘‘the worst nausea ever.’’ Unpaired t tests were used to compare scores at baseline and at the 3-minute post-aromatherapy interval between groups while paired t tests were used for within group comparisons at the two time points. Independent t tests were used to compare scores on the patient satisfaction question with 0 5 ‘‘completely dissatisfied’’ and 10 5 ‘‘completely satisfied’’ and the perceived effectiveness of aromatherapy question with 0 5 ‘‘completely ineffective’’ 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 experienced PONV. Ninety-four patients received an inhaler device; 54 received the treatment inhaler and 40 received the placebo inhaler. Twentyseven patients were not offered the inhaler for various reasons such as the nurse did not realize the
patient was enrolled in the study before giving the intravenous antiemetic, had not received training 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 administered. 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, P 5 .03 (Figure 1). Perceived effectiveness of aromatherapy was examined between groups. The scores for patients in the treatment group (M 5 5.72 6 3.26) were higher than in the placebo group (M 5 2.72 6 3.12). This 3-point difference between means was statistically significant (95% confidence interval 5 1.60 to 4.39 points; two-tailed Student t test, t 5 4.27; df 5 84; P , .001). Independent sample t tests showed no difference between groups on their ratings of overall satisfaction with nausea management; both groups rated satisfaction between 6.8 and 7.1 on the 0-10 Likert scale (Figure 2).
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While generally pleasing to patients, one patient did say the fragrance made the nausea worse.
Figure 1. Mean difference initial and follow-up nausea scores.
Ten percent of the patients were randomly selected to volunteer additional information in a brief interview concerning their aromatherapy experience. Comments suggested that the aromatherapy was more effective for lower levels of nausea. Several 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 effective 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 because he did not even need to use his own oils.
Evidence-based nursing interventions are desperately 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 patients. 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 frequently commented that the lack of effectiveness and negative side effects of antiemetics were major concerns for them, especially those who recounted 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 attributed 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 metabolism of several anesthesia drugs.18 Further exploration is warranted as nicotine patches have been unable to produce the same results.19 The overall success of the aromatherapy and the positive experience for staff nurses led to rapid approval 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 outpatient 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 Figure 2. Mean difference satisfaction overall and perceived effectiveness.
The study results are limited to the experience in a single institution with the only product of its
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kind on the market at the time. The research team was comprised strictly of volunteers and subject accrual was somewhat dependent on the availability of the team on any given day. However, there were no attempts to seek out a specific population and the results demonstrate that patients underwent a wide range of surgical procedures. There were more female volunteers, but this is a reflection of the high number of gynecologic procedures 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 altered 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 effectiveness of rescue medications when aromatherapy was ineffective. Lastly, the sample size fell short of the recommended number for enrollment according to the a priori power analysis, but statistical significance was achieved nonetheless.
Further Research The current interest in complementary and alternative 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. Comparisons between modalities for nausea such as aromatherapy and antiemetic bands, or guided imagery, or music, would make interesting evidence-based practice research activities. Such information may strengthen the evidence for aromatherapy or identify adjunct modalities to enhance patient comfort.
Conclusion In conclusion, the use of aromatherapy and a dedicated team of nurses led to a high rate of satisfaction with overall management of PONV on the medical-surgical units. Aromatherapy was favorably received by most patients and represents an effective treatment option for postoperative nausea. 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 administered. This evidence-based nursing therapy is now available to the bedside nurse in our institution to offer to patients with postoperative nausea. Continued use and additional data will help to determine if this intervention is deserving of a best practice recommendation for bedside nurses caring for postoperative patients.
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PONV AROMATHERAPY STUDY 11. Wang SM, Hofstadter MB, Kain ZN. An alternative method to alleviate postoperative nausea and vomiting in children. J Clin Anesth. 1999;11:231-234. 12. Merritt BA, Okyere CP, Jasinski DM. Isopropyl alcohol inhalation. Nurs Res. 2002;51:125-128. 13. Anderson LA, Gross JB. Aromatherapy with peppermint, isopropyl alcohol, or placebo is equally effective in relieving postoperative nausea. J Perianesth Nurs. 2004;19:29-35. 14. Chaiyakunapruk N, Kitikannakorn N, Nathisuwan S, et al. The efficacy of ginger for the prevention of postoperative nausea and vomiting: A meta-analysis. Am J Obstet Gynecol. 2006;194:95-99. 15. Kim JT, Wajda M, Cuff G, et al. Evaluation of aromatherapy in treating postoperative pain: Pilot study. Pain Pract. 2006;6:273-277.
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