|Year : 2014 | Volume
| Issue : 6 | Page : 574-580
The effect of lavender essential oil on anxiety level in patients undergoing coronary artery bypass graft surgery: A double-blinded randomized clinical trial
Zahra Seifi1, Ali Beikmoradi2, Khodayar Oshvandi3, Jalal Poorolajal4, Malihe Araghchian5, Reza Safiaryan6
1 Master of Science Critical Care Nursing, Larestan School of Medical Science, Larestan, Iran
2 Chronic Diseases (Home Care) Research Center Hamadan University of Medical Sciences, Hamadan, Iran
3 Mother and Child Care Research Center Hamadan University of Medical Sciences, Hamadan, Iran
4 Department of Epidemiology and Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
5 Department of Pharmacology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
6 Department of Heart Surgery, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
|Date of Submission||21-Aug-2013|
|Date of Acceptance||13-Feb-2014|
|Date of Web Publication||25-Oct-2017|
Dr. Ali Beikmoradi
Chronic Diseases (Home Care) Research Center Hamadan University of Medical Sciences, Shahid Fahmideh Ave., Hamadan
Source of Support: None, Conflict of Interest: None
Clinical trial registration 201203299014N9
Background: Open heart surgery can cause high levels of anxiety in patients. Nowadays, lavender essential oil is widely used in medical research. This study was conducted with an aim to investigate the effects of lavender essential oil to reduce the anxiety of patients after coronary artery bypass surgery.
Materials and Methods: This research is double-blinded randomized controlled trial on 60 patients who had undergone coronary artery bypass surgery in a 2-day intervention targeting reduction of anxiety. This study was conducted in Ekbatan Therapeutic and Educational Center, Hamadan city, Iran, in 2013. The patients in the inhalation aromatherapy group inhaled two drops of 2% lavender essential oil and those in the control group inhaled two drops of distilled water as placebo for 20 min on the 2 nd and 3 rd days after surgery. The level of anxiety was evaluated by Spielberger's State Anxiety questionnaire before and after intervention and the vital signs were documented as well. Data were analyzed using Stata 11 (Stata Corp., College Station, TX, USA) by independent t-test for continuous variables and Chi-square test for categorical variables.
Results: The mean score of anxiety in the aromatherapy group was 48.73 ± 5.08 and in the control group was 48 ± 6.98 before the intervention (P = 0.64), which reduced after the intervention to 42.6 ± 5.44 and 42.73 ± 7.30, respectively. On the 3 rd day after surgery, the mean score of anxiety in the aromatherapy group was 46.76 ± 4.07 and in the control group was 46.53 ± 7.05 before the intervention, which reduced to 41.33 ± 3.65 and 41.56 ± 6.18, respectively, after the intervention. However, there was no statistically significant difference in the mean scores of anxiety between the aromatherapy and control groups.
Conclusions: Lavender essential oil has no significant effect on anxiety in patients after coronary artery bypass surgery, although it decreased the level of anxiety in the patients.
Keywords: Anxiety, aromatherapy, coronary artery bypass, Iran, plant medical
|How to cite this article:|
Seifi Z, Beikmoradi A, Oshvandi K, Poorolajal J, Araghchian M, Safiaryan R. The effect of lavender essential oil on anxiety level in patients undergoing coronary artery bypass graft surgery: A double-blinded randomized clinical trial. Iranian J Nursing Midwifery Res 2014;19:574-80
|How to cite this URL:|
Seifi Z, Beikmoradi A, Oshvandi K, Poorolajal J, Araghchian M, Safiaryan R. The effect of lavender essential oil on anxiety level in patients undergoing coronary artery bypass graft surgery: A double-blinded randomized clinical trial. Iranian J Nursing Midwifery Res [serial online] 2014 [cited 2022 Dec 4];19:574-80. Available from: https://www.ijnmrjournal.net/text.asp?2014/19/6/574/146222
| Introduction|| |
Coronary artery bypass graft (CABG) surgery is a common form of treatment for patients with coronary stenosis and more than 73 million surgeries are performed annually only in the United States.  Despite achieving technical success for most patients, clinically significant morbidities such as cardiologic shock, dysrhythmia, gastrointestinal bleeding, pain, anxiety, and vital sign changes are common. ,,
CABG is reported to be associated with pre- and postoperative anxiety and may impair the coronary circulation and, hence, increase the risk of angina pectoris and myocardial infarction.  In one of the studies, the prevalence of anxiety after open heart surgery in patients has been reported to be 24.7%.  There are a number of factors that may increase anxiety in patients admitted in the intensive care unit (ICU), including pain, sleep disorder, absence from home and work, long-term treatment and disease, economic problems, and lack of social support such as insurance, family and social problems , Anxiety can cause tachypnea, increased blood pressure, hypothermia, arterial vasoconstriction, and decreased tissue perfusion through stimulation of the sympathetic response.  Anxiety is a considerable challenge that can indirectly increase postoperative pain and analgesic usage, decrease resistance against infection, prolong postoperative wound healing,  and increase the duration of hospitalization. 
Sedative medications are frequently used to decrease anxiety among patients who had undergone CABG, which is usually associated with adverse effects such as sedation and respiratory depression. 
Complementary and alternative medicine (CAM) therapies are safer than pharmacologic approaches and have less adverse effects. Aromatherapy is a natural treatment method that utilizes the chemical structure and effects of essential oils. It can be applied in various forms such as massage, inhalation, compress, and baths with herbal and mineral substances. Use of aromatherapy has grown substantially in recent years compared to other medical approaches. , Inhalation aromatherapy is a technique in which essential oils are used in inhalation,  which can decrease pain, anxiety, depression, and improve the vital signs. ,,
Lavender is one such plant that is widely used in aromatherapy, with aromatic leaves and attractive bracts at the top of flowers. Some of its effects are sedative, antidepressant, antispasmodic, antibacterial, and local anesthetic. It also can be used in relieving migraines and insomnia. , Studies about the benefits of lavender's aroma showed that linalool and linalyl acetate present in this plant can stimulate parasympathetic system. In addition, linalyl acetate has narcotic effects and linalool acts as a sedative. , This herb improves the heart function and as a circulatory stimulant, it has beneficial effects on coronary blood flow.  Studies have shown that inhalation of lavender aromatherapy is effective in reducing depression, pain, and anxiety in women undergoing cesarean section and in patients undergoing dental procedures or abdominal surgery. ,,
CABG is a relatively common procedure for treatment of coronary stenosis. It is usually a stressful event for patients,  indicating the importance of anxiety reduction strategies and stable vital signs in them. The intensive care nurses have an important role in assessment of anxiety and changes in vital signs, implementation of appropriate measures, and evaluation of therapeutic effects. Accordingly, this study was carried out with an aim to investigate the effects of inhalation aromatherapy using lavender oil to reduce anxiety in patients after CABG.
| Materials and Methods|| |
A double-blinded randomized controlled trial was conducted on 60 patients who had undergone CABG in Ekbatan Therapeutic and Educational Center, Hamadan city, Iran. The entire study process was approved by the Research Ethics Committee of Hamadan University of Medical Sciences, and the protocol was registered by Iranian Registry of Clinical Trials (No.: 201203299014N9).
The details of the study were explained to the participants and their informed consent was obtained in writing. In order to avoid inductive effect of the medication, both patients and interviewers were unaware of the treatment each patient had received. For this purpose, the medications were given to the patients by one researcher and the effect of treatments was evaluated by another researcher independently.
The inclusion criteria included the absence of (a) chronic respiratory disease, (b) addiction to alcohol or narcotic substances, (c) history of head trauma or convulsion, (d) impaired sense of smell, (e) using anti-anxiety drugs, and (f) acute mental illness according to physician diagnosis and obtaining a score of less than 20 with Spielberger's questionnaire. Patients were excluded if they had (a) eczema or allergy to plants, (b) impaired consciousness, (c) been intubated for more than 24 h, (d) hemodynamic instability, and (e) severe acute pain at the time of completing the questionnaire.
The eligible patients were randomly assigned to the aromatherapy and control groups using balanced block randomization with a block size of four. For this purpose, the aromatherapy and control groups were randomly assigned to letters A and B. Thus, for each block of four patients, two sequence different assignments were made for each treatment. Six sheets of paper were used. In the papers were written all the possible states, i.e. Paper No. 1 for AABB, Paper No. 2 for ABAB, Paper No. 3 for ABBA, Paper No. 4 for BBAA, Paper No. 5 forBABA, and Paper No. 6 or BAAB. Then the number were selected randomly via table of random numbers. According to number of selected papers, the patients respectively were in the aromatherapy or control groups.
Participants (N = 70) were randomly assigned to two groups: Aromatherapy (n = 35) and control group (n = 35). Follow-up of patients was lost in the aromatherapy (n = 3) and control groups (n = 4) due to them getting discharged on the 3 rd day after surgery. Intervention was discontinued in the aromatherapy group (n = 2) due to intolerance of aromatherapy and in the control group (n = 1) due to lack of cooperation. Thus, in each of the aromatherapy and control groups, n = 30 were analyzed.
Data collection was based on completing the questionnaire, interviewing, and recording the vital signs. The data collection tool included a questionnaire with two parts and a checklist of items. The first part of the questionnaire contained demographic information such as age, gender, body mass index (BMI), educational level, and marital status. Additional information obtained included history of hospitalization or open heart surgery in the family, as well as the duration of operation and admission in the ICU. For assessing the scientific validity of this part of the questionnaire, content validity was used.
The second part of the questionnaire consisted of the standard questionnaire of Spielberger. It included 20 questions related to the State Trait Anxiety Inventory (STAI). The least score of 20 that could be obtained indicated no anxiety and the maximum score of 80 illustrated the highest level of anxiety. A score of 21-39 indicated mild anxiety. A score of 40-59 indicated moderate anxiety, and a score of 60-80 indicated severe anxiety.  This questionnaire enjoys universal validity and reliability. Its reliability had already been confirmed on 600 people in Mashhad and the Cronbach's alpha coefficient obtained was 0.94 in the norm population. This questionnaire has been used in local and international studies widely.  The checklist of items was used to recode vital signs such as systolic and diastolic blood pressure, heart and respiratory rates, and temperature measured by a monitoring machine manufactured by Sairan Co. Iran.
Based on a single-blind clinical trial conducted in 2011 by Hadi et al.,  the sample size needed in our study was estimated to be 30 subjects in each arm (totally 60) with P at 0.05 and 90% power. There were 30 subjects in the aromatherapy group and 30 subjects in the control group, who contributed data to the study according to the trial profile [Figure 1]. The eligible patients were randomly assigned to the aromatherapy and control groups using balanced block randomization with a block size of four.
The patients in the aromatherapy group inhaled two drops of 2% lavender essential oil, produced by Barij Esans Co. Iran (kashan), via an absorbable patch connected inside an oxygen mask for 20 min  on the 2 nd and 3 rd days  after surgery. The patients in the control group received two drops of distilled water as placebo via an oxygen mask at the same time as the aromatherapy group. On the 2 nd and the 3 rd days after surgery, in the aromatherapy and control groups, anxiety was measured before and 20 min after the intervention  using Spielberger's questionnaire. Vital signs including heart rate, respiratory rate, and systolic and diastolic blood pressure were measured before the intervention and then at 5 th , 30 th , and 60 th minute after the intervention , by a monitoring machine.
All statistical analyses were performed at a confidence level of 0.05 using the statistical software Stata 11 (Stata Corp., College Station, TX, USA). The relationship between the dependent and independent variables was investigated using independent statistical t-test for continuous variables and Chi-square test for categorical variables.
| Results|| |
[Table 1] shows the distribution of individual characteristics of the patients in aromatherapy and control groups. Majority of patients in the aromatherapy group (n = 19) and the control group (n = 23) were males and the rest females. The mean age in the aromatherapy group was 65.13 ± 9.76 years and in the control group was 65.63 ± 10.80 years. According to the results presented in the table, there was no statistically significant difference between the aromatherapy and control groups regarding the individual characteristics that might have an effect on the treatment.
|Table 1: Distribution of individual characteristics of the patients in aromatherapy (lavender) and control (placebo) groups|
Click here to view
[Table 2] shows the mean score of anxiety based on the Spielberger's questionnaire On the 2 nd day after surgery, the mean score of anxiety before intervention in the aromatherapy group was 48.73 ± 5.08 and in the control group was 48 ± 6.98, which reduced after the intervention to 42.6 ± 5.44 and 42.73 ± 7.30, respectively (P = 0.541). On the 3 rd day after surgery, the mean score of anxiety before intervention in the aromatherapy group was 46.76 ± 4.07 and in the control group was 46.53 ± 7.05, which reduced after the intervention to 41.33 ± 3.65 and 41.56 ± 6.18, respectively (P = 0.672). However, the mean score of anxiety decreased significantly after surgery in both groups (P = 0.032, P = 0.036), but the difference between aromatherapy and control groups before and after intervention was significant neither on the 2 nd day (P = 0.36) nor on the 3 rd day (P = 0.41) after surgery
|Table 2: Comparison of the mean difference of anxiety among the intervention (lavender) and control (placebo) groups according to Spielberger's questionnaire using independent t-test|
Click here to view
[Table 3] shows the changes in vital signs of the patients in aromatherapy and control groups before the intervention and at 5 th , 30 th , and 60 th minute after the intervention on the 2 nd and 3 rd days after surgery. There was no statistically significant difference in the vital signs (P = 0.06), except in the systolic blood pressure (P = 0.004), between the aromatherapy and control groups either on the 2 nd day or on the 3 rd day after surgery.
|Table 3: Comparison of the mean difference in homodynam ic measurements in intervention (lavender) and control (placebo) groups using independent t-test|
Click here to view
| Discussion|| |
Some studies have reported that the level of anxiety is different between males and females. Nonetheless, we did not find any significant difference in the mean score of anxiety between the two sexes. Furthermore, we found no relationship between educational level and anxiety. Dehdari et al. reported similar results. 
Open heart surgery is a stressful approach. Several studies have reported that patients who had undergone CABG suffer from anxiety after surgery. , We found that patients had moderate anxiety before the intervention in both aromatherapy and control groups. However, their anxiety deceased significantly after the intervention, although no statistically significant difference was observed between the two groups. One possible reason for this is that pain and other reasons of stress like fear of surgery and anesthesia had been resolved. Fear and anxiety of the future health status may remain after surgery which may affect the mental health status.
Rymazewska et al.  reported that patients who are candidates for CABG have severe anxiety before surgery, but their anxiety decreases considerably a few days after surgery and increases gradually 3 months thereafter.
Many studies have been conducted with an aim to decrease anxiety in the patients using aromatherapy. , In accordance with our results, Muzzarelli et al.  indicated that inhalation aromatherapy using lavender essential oil had no significant effect on anxiety (P = 0.630). The result reported by Garham et al.  indicated that inhalation aromatherapy did not have any effect on reducing anxiety in patients who underwent radiotherapy; even the level of anxiety in the control group was less than that in the aromatherapy group. The reason for increase in anxiety level could be due to the association between specific odor and anxiety caused by radiotherapy.
On the other hand, the study of Lehrner et al. showed that inhalation aromatherapy with lavender essential oil could reduce the anxiety level before the dental procedure (P = 0.039), which was not in accordance with the present study. The length of inhalation in the both studies was 20 min. Perhaps this is due to the doses of lavender used in Lehrner et al.'s study. In their study, lavender essential oil combined with orange had been used, whereas in this study, pure herbal essential oil was used. 
The study of Conrad et al. indicated that inhalation aromatherapy with lavender essential oil could reduce anxiety and depression postpartum, which was not in accordance with the results of this study.  The reason for the dissimilarity could be the duration of intervention. In Conrad et al.'s study, 15-min sessions as 2 times per week for 4 consecutive weeks were used, whereas 20-min sessions for two consecutive days were used in the present study. The mean level of anxiety might become statistically different between the two groups if the duration of intervention is changed.
The results of the study by Lee et al. showed that inhalation aromatherapy with lavender essential oil could reduce anxiety in women undergoing cesarean section, which was not in accordance with the results of this study.  The reason for the dissimilar results could be the duration of inhalation. In the study of Lee et al., women received aromatherapy with lavender essential oil for 5 min, whereas it was 20 min in the present study.
In this study, we found that lavender essential oil had no significant effect on the vital signs except systolic blood pressure. In accordance with the results of our study, Hwang et al.,  in their investigation on the effect of inhalation aromatherapy with lavender essential oil on blood pressure, reported that lavender could significantly reduce the blood pressure (P < 0.05).
On the other hand, Shiina et al.  reported that lavender essential oil had no effect on blood pressure. The discrepancy between the study results may be due to the difference in the dose of lavender used in the studies. Rho et al.  reported that aromatherapy had no significant effect on the respiratory rate as we showed in this study.
Limitations of the study are with regard to the relationship between smells and memories. Smells can trigger memories. If the smell of essential oils closely associated with the negative memories is applied to the patient, it may lead to negative results.
| Conclusion|| |
In summary, inhalation aromatherapy with lavender essential oil had no significant effect on anxiety and vital signs, except for systolic blood pressure, in patients who had undergone coronary artery bypass surgery; so our hypothesis was rejected. These results could be influenced by the relationship between specific smell and stressful experience in coronary artery bypass surgery. Applying inhalation aromatherapy with lavender essential oil can be considered by nurses, physicians, and other members of the treatment team based on the results of this study and also since using complementary methods reduces the side effects of medications. Further studies about the long-term effects of usage of this method for reducing anxiety are recommended.
| Acknowledgments|| |
We offer our best thanks and gratitude to the authorities of Hamadan Nursing and Midwifery School, Deputy of Research and Technology of the Hamadan University of Medical Sciences, authority and staffs of Ekbatan Hospital of Hamadan city, and dear CABG patients who participated in this research. This paper was a part of Critical Care Nursing M.S. thesis which was approved by the Deputy of Research and Technology of Hamadan University Medical Sciences.
| References|| |
Centers for Disease Control and Prevention. Fast stats. Atlanta: CDC; 2013. [updated 2013 24 October 2011. Available from: http://www.cdc.gov/nchs/fastats. [Last accessed on 2013 Jan 13].
Bauer BA, Cutshall SM, Wentworth LJ, Engen D, Messner PK, Wood CM, et al
. Effect of massage therapy on pain, anxiety, and tension after cardiac surgery: A randomized study. Complement Ther Clin Pract 2010;16:70-5.
Geissler HJ, Fischer UM, Grunert S, Kuhn-Régnier F, Hoelscher A, Schwinger RH, et al
. Incidence and outcome of gastrointestinal complications after cardiopulmonary bypass. Interact Cardiovasc Thorac Surg 2006;5:239-42.
Nalysnyk L, Fahrbach K, Reynolds MW, Zhao SZ, Ross S. Adverse events in coronary artery bypass graft (CABG) trials: A systematic review and analysis. Heart 2003;89:767-72.
Shiina Y, Funabashi N, Lee K, Toyoda T, Sekine T, Honjo S, et al
. Relaxation effects of lavender aromatherapy improve coronary flow velocity reserve in healthy men evaluated by transthoracic Doppler echocardiography. Int J Cardiol 2008;129:193-7.
Krannich J, Weyers P, Lueger S, Herzog M, Bohrer T, Elert O. Presence of depression and anxiety before and after coronary artery bypass graft surgery and their relationship to age. BMC Psychiatry 2007;7:1-6.
Gallagher R, Mckinley SH. Stressors and anxiety in patients undergoing coronary artery bypass surgery. Am J Crit Care 2007;16:248-57.
Durling M, Milne D, Hutton N, Ryan S. Decreasing patient's preoperative anxiety: A Literature review. Aust Nurs J 2007;14:35-41.
Barker R, Kober A, Hoerauf K, Latzke D, Adel S, Kain Z. Out-of-hospital auricular acupressure in elder patients with hip fracture: A randomized double-blinded trial. Acad Emerg Med 2006;13:19-23.
Granot M, Goldstein FS. The roles of pain catastrophizing and anxiety in the prediction of postoperative pain intensity: A prospective study. Clin J Pain 2005;21:439-45.
Kalkman CJ, Visser K, Moen J, Bonsel GJ, Grobbee DE, Moons KG. Preoperative prediction of sever postoperative pain. Pain 2003;105:415-23.
Agarwal A, Ranjan R, Dhiraaj S, Lakra A, Kumar M, Singh U. Acupressure for prevention of pre-operative anxiety: Aprospective, randomised, placebo controlled study. Anaesthesia 2005;60:978-81.
Fayazi S, Babashahi M, Rezaei M. The effect of inhalation aromatherapy on anxiety level of patients in preoperative period. Iran J Nurs Midwifery Res 2011;16:278-83.
Kutlu AK, Yýlmaz E, Çeçen D. Effects of aroma inhalation on examination anxiety. Teach Learn Nurs 2008;3:125-30.
Hur M-H, Lee M, Kim C, Ernst E. Aromatherapy for treatment of hypertension: A systematic review. J Eval Clin Pract 2012;18:37-41.
Kim S, Kim HJ, Yeo JS, Hong SJ, Lee JM, Jeon Y. The effect of lavender oil on stress, bispectral index values, and needle insertion pain in volunteers. J Altern Complement Med 2011;17:823-6.
Lee SO, Hwang JH. Effects of aroma inhalation method on subjective quality of sleep, state anxiety, and depression in mothers following cesarean section delivery. J Korean Acad Fundam Nurs 2011;18:54-62.
Boehm K, Büssing A, Ostermann T. Aromatherapy as an adjuvant treatment in cancer care: A descriptive systematic review. Afr J Tradit Complement Altern Med 2012;9:503-18.
Kerachian N, Alaee H, Gharavi-Naini M, Pilevarian Aa, Moghimi A. Effects of alcoholic extract of Avena sativa, Hypericum perforatum, Passiflora incarnata and Lavandula officinalis on symptoms of morphine withdrawal syndrome in rats. Physiol Pharmacol 2007;10:313-21.
Pirali-Kheirabadi K, Silva JATd. Lavandula angustifolia essential oil as a novel and promising natural candidate for tick (Rhipicephalus (Boophilus) annulatus) control. Exp Parasitol 2010;126:184-6.
Daghighbin E. Comparison of Honey and Lavender Cream on Pain and Wound Healing in Primigravidas Episiotomy. Ahvaz: Ahvaz Junishapur University of Medical Sciences; 2007.
Lehrner J, Marwinski G, Lehr S, Johren P, Deecke L. Ambient odors of orange and lavender reduce anxiety and improve mood in a dental office. Physiol Behav 2005;86:92-5.
Cooke B. Aromatherapy: A systematic review. Br J Gen Pract 2000;50:493-6.
Abolhassani S. Effect of sensory stimulation on signs of sleep deprivation and heart inductor in patient on intensive care uni. Isfahan: Isfahan University of Medical Sciences; 2002.
Hadi N, Hanid A. Lavender essence for post-cesarean pain. Pak J Biol Sci 2011;14:664-7.
Graham PH, Browne L, Cox H, Graham J. Inhalation aromatherapy during Radiotherapy: Results of a placebo-controlled double-blind randomized trial. J Clin Oncol 2003;21:2372-6.
Buckle J. Aromatherapy. does it matter which lavender essential oil is used? Nurs Times 1993;89:32-5.
Cho MY, Min ES, Hur MH, Lee MS. Effects of aromatherapy on the anxiety, vital signs, and sleep quality of percutaneous coronary intervention patients in Intensive Care Units. Evid Based Complement Alternat Med 2013;2013:381381
Morris N, Birtwistle S, Toms M. Anxiety reduction by aromatherapy: Anxiolytic effects of inhalation of geranium and rosemary. Int J Aromatherapy 1995;7:33-9.
Dehdari T, Heidarnia A, Ramezankhani A, Sadeghian S, Ruchi FG, Babaei GH, et al
. Effects of phase III cardiac rehabilitation programs on anxiety and quality of life in anxious patients after coronary artery bypass surgery. J Teh Univ Heart Ctr 2007;2:207-12.
Tully PJ, Bennetts JS, Baker RA, McGavigan AD, Turnbull DA, Winefield HR. Anxiety, depression, and stress as risk factors for atrial fibrillation after cardiac surgery. Heart Lung 2011;40:4-11.
Rymazewska J, Kiejna A. Depression and anxiety after coronary artery bypass grafting. Pol Merkur Lekarski 2003;15:193-5.
Muzzarelli L, Force M, Sebold M. Aromatherapy and Reducing Preprocedural Anxiety: A Controlled Prospective Study. Gastroenterol Nurs 2006;29:466-71.
Graham P, Browne L, Cox H, Graham J. Inhalation aromatherapy during radiotherapy: Results of a placebo-controlled double-blind randomized trial. J Clin Oncol 2003;21:2372-6.
Conrad P, Adams C. The effects of clinical aromatherapy for anxiety and depression in the high risk postpartum woman-A pilot study. Complement Ther Clin Pract 2012;18:164-8.
Hwang JH. The effects of the inhalation method using essential oils on blood pressure and stress responses of clients with essential hypertension. Taehan Kanho Hakhoe Chi 2006;36:1123-34.
Rho KH, Hall SH, Kim K. Effect of aromatherapy massage on anxiety and self -steem in Korean elderly women. Int J Neurosci 2006;776:1446-55.
[Table 1], [Table 2], [Table 3]