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The Effects of Aroma Essential Oil Inhalation on Stress, Pain, and Sleep Quality in Laparoscopic Cholecystectomy Patients: A Randomized Controlled Trial
Correspondence to: Myung-Haeng Hur, RN, PhD, College of Nursing, Eulji University, 712, Dongil-ro, Uijeongbu-si, Gyeonggi-do, 11759, Republic of Korea.
Patients undergoing cholecystectomy report experiencing stress related to the surgery, complaining of pain and poor sleep quality. Aromatherapy is known to have positive effects on these complaints. However, the effect of aromatherapy on cholecystectomy patients has yet to be determined. The aim of this study, therefore, was to investigate the effects of aromatherapy on laparoscopic cholecystectomy patients’ stress, pain, and sleep quality.
Methods
This study was a randomized controlled trial involving 69 adults who underwent laparoscopic cholecystectomy. Essential oil therapy was given to an intervention group, and almond oil was given to a placebo group. The outcome variables were stress, pain, and sleep quality.
Results
There were no differences between the groups in terms of demographic and clinical characteristics and pretreatment dependent variables. After the intervention, subjective stress (F = 7.43, p < .001), objective stress (F = 2.70, p = .034), parasympathetic nerve activity (F = 2.65, p = .036), pain (F = 8.74, p < .001), analgesics administration (F = 22.43, p < .001), and sleep quality (F = 5.23, p < .001) were significantly different between the intervention, placebo, and control groups. Sympathetic nerve activity was not significantly different. The effect sizes regarding the sleep quality of the intervention versus control group and the intervention versus placebo group were 1.92 and 1.52, respectively.
Conclusion
Postoperative aromatherapy received by cholecystectomy patients was effective in reducing stress and pain and improving sleep quality. No side effects of aromatherapy were reported during the experimental treatment.
The incidence of gallbladder disease is gradually increasing in Korea due to the influence of Westernized lifestyles, high-protein and high-fat diets, and the rising prevalence of obesity [
]. Cholecystectomy and antibiotic therapy are common treatments for inflammation caused by gallbladder disease. Open cholecystectomy has the disadvantages of involving large surgical incisions, severe pain, and long hospital stays; therefore, laparoscopic cholecystectomy may be performed to minimize surgical incisions and shorten hospital stays [
Laparoscopic cholecystectomy requires three incisions, and patients undergoing such surgery under general anesthesia still experience stress, complaining of severe postoperative pain [
] and discomfort during hospitalization. Accordingly, relieving stress, assuaging anxiety, and lessening pain, i.e., ensuring patient comfort, are paramount during postoperative care [
Effects of PCA (patient controlled analgesics) education Program including practicum on postop pain of gynecologic laparoscopic surgery patients algesics.
]. For short hospitalizations following laparoscopic cholecystectomy, however, nonsteroidal and narcotic analgesics are used instead of PCA to control pain.
Laparoscopic cholecystectomy patients may also suffer from psychological helplessness and sleep disorders [
]. Sleep is a basic human need, and sound sleep provides stability and relaxation, which is essential for maintaining mental homeostasis and physiological health [
]. Stress and sleep disorders affect the autonomic nervous system, with various physiological changes occurring in the body activating the sympathetic nervous system and inhibiting the stimulation of the parasympathetic nervous system [
]. As sleep deficiency is a form of stress and postoperative pain interferes with sleep, a patients recovery is negatively affected; therefore, active efforts to overcome sleep deprivation are necessary [
The effect of topical application of lavender essential oil on the intensity of pain caused by the insertion of dialysis needles in hemodialysis patients: a randomized clinical trial.
]. The aromatherapy essential oils used in this study were intended to balance the autonomic nervous system by activating the parasympathetic nerve. Since lavender oil, ylang-ylang oil, and marjoram oil are effective for insomnia treatment and gentle sedation, these oils were blended and applied [
]. Among the various aromatherapy methods, the method that is frequently used safely is the inhalation method. In this study, the inhalation method using an aroma stone was employed, having the advantages of being portable and easy to use [
Effect of inhalation aromatherapy with lavender essential oil on stress and vital signs in patients undergoing coronary artery bypass surgery: a single-blinded randomized clinical trial.
]. However, there have been no aromatherapy studies on patients undergoing laparoscopic cholecystectomy. Moreover, studies on aromatherapy for improving sleep have focused on elderly inpatients [
], with few studies examining the effects of aromatherapy on surgical patients.
This study was conducted to identify the postoperative comfort and symptom improvement effect of applying a proven, safe aroma inhalation therapy. A blended essential oil containing lavender, ylang-ylang, marjoram, and neroli was inhaled by patients who underwent laparoscopic cholecystectomy to treat gallbladder disease, and attempts were made to determine the oil’s effects on stress, pain, and sleep quality on the first and second days after surgery.
Methods
Study design
This study used a randomized, single-blind, parallel-group controlled trial to investigate the effects of aroma essential oil inhalation on stress, pain, and sleep quality in patients undergoing laparoscopic cholecystectomy. The study design is shown in Figure 1.
The participants were patients diagnosed with gallbladder disease at Eulji Medical Center in Daejeon City, South Korea, who were recommended for laparoscopic cholecystectomy. The sample size was calculated using G-power 3.1.9.2., considering alpha, power, the number of groups, the number of measurements, the correlation coefficient of repeated measures, and the effect size obtained from previous studies using the statistical method of repeated measures ANOVA. The values used were alpha .05, power .95, number of groups 3, number of measurements 3, a correlation coefficient of .20, and the effect size .27 was obtained by substituting .07 partial eta squared in a previous study [
]. The required number of patients was 69, which was then set at 75, considering a dropout rate of 10%.
The researcher explained the study in accordance with research ethics regulations to patients admitted for laparoscopic cholecystectomy, checked the inclusion criteria and exclusion criteria, and selected 85 patients. To be included, patients had to be scheduled to undergo laparoscopic cholecystectomy under general anesthesia, able to communicate, fully understand the purpose and procedure of the study, and agree to participate sincerely. Patients taking antidepressants or sleeping pills, those with allergies that could affect inhalation of aroma essential oils, and those with low blood pressure were excluded. The 75 patients were chosen after the exclusion of seven patients taking antidepressants and sleeping pills and three who did not consent to participation in the study.
The study was conducted after randomly assigning 25 patients to each group—the intervention group, the placebo group, and the control group—using Excel’s random number method. No information was provided to the patients about their assigned group; however, for the researchers, blindness could not be maintained due to the nature of the aromatherapy intervention. During the study, one of the intervention group patients was unable to continue due to vomiting immediately after surgery, and another participant inhaled the aroma essential oil but then refused postmeasurements to be obtained. One of the placebo group patients withdrew from the study after being unable to identify a smell, and another participant also withdrew because of the discomfort felt during postmeasurement. Two of the control group patients were excluded because they refused postmeasurement; therefore, the total study patients numbered 23 in each group (Figure 2).
To confirm the homogeneity between the three groups, the patients completed a questionnaire on demographic characteristics.
Primary outcomes
Stress
For measuring the degree of stress perceived by the patients, subjective stress was measured using an 11-point numeric rating scale (NRS), from no stress (0 points) to extreme stress (10 points). The patients’ subjective stress was measured on the day of admission, the morning of surgery, immediately after surgery, and the first and second days following surgery (Figure 1). Objective stress was evaluated based on a stress index, sympathetic nerve activity, and parasympathetic nerve activity. The autonomic nervous system was continuously measured for 2 minutes 30 seconds using Canopy9 professional 4.0 (IEMBIO, Chuncheon, Korea). This is a device that measures the degree of autonomic nervous system abnormality and stress using an accelerated pulse wave graph (APG) and heart rate variability (HRV). It is a method of measuring sympathetic and parasympathetic activity by quantifying a current stress state using a standard induction method. The machine is noninvasive and produces fast results. The stress index was based on HRV. The index ranged from 1 to 10—the higher the number, the more an individual was experiencing stress. As the measured sympathetic nerve activity increased and the measured parasympathetic nerve activity decreased, the more an individual was experiencing stress. Objective stress was measured on the day of hospitalization and the first and second days after surgery.
Pain
The pain experienced by the patients was measured using an 11-point numeric rating scale (NRS), from no pain (0 points) to severe pain (10 points). This was measured on the day of hospitalization, the morning of surgery, immediately after surgery, and the first and second days after surgery. Another method was to check the number of pain control injections. Since pain is a subjective concept, to objectively evaluate pain levels, administration records were checked to establish the number of times analgesics of the same component were administered.
Secondary outcomes
Sleep quality
For measuring sleep quality, the VSH sleep scale [
], was used after obtaining approval from the original author and the author of the translation. Eight of nine items were measured using a 10-point scale, resulting in a score ranging from 0 to 80 points: the higher the total score, the higher the quality of sleep. This was measured on the day of hospitalization, the morning of surgery, and the first and second days after surgery.
The reliability at the time of tool development was Cronbach’s α = .82. The reliability of this study using Cronbach’s α was α = .83, α = .90, α = .70, and α = .79, on the day of admission, the day of surgery, the first day after surgery, and the second day after surgery, respectively.
Intervention
In this study, routine postoperative care was provided to all patients according to the code of ethics. Essential oil therapy was given to the intervention group, almond oil therapy, chosen because the oil’s color was similar to the essential oil used for the intervention group, was given to the placebo group, and routine care was received by the control group. The essential oils used in this study were produced by Neumond (website: http://www.neumond.de) and purchased from Bestbeing, Korea (website: http://www.bestbeing.co.kr). The oils used were selected and blended by MH, an international aromatherapist, and applied by inhalation following the instructions.
Essential oils can be classified into top notes, middle notes, and base notes [
]. The duration of fragrances varies depending on the oil, with top notes usually evaporating within 3 hours. The scent retention time of middle notes can be as short as 5 hours or as long as 3 days. As time passes, the reverberation becomes extremely light. The oils used in this study were ylang-ylang (middle note), lavender (middle note), marjoram (middle note), and neroli (middle or top note) [
]. Based on the characteristics of each oil, blending was conducted under the guidance of aroma experts. The lavender, ylang-ylang, marjoram, and neroli oils were mixed in a ratio of 5:2:1:0.5 and stored in a refrigerator.
The oils were inhaled immediately after surgery and again over the next two days. For the aroma intervention and placebo groups, three drops of oil were placed on an aroma stone located 30 cm from the patients’ beds upon returning to their wards after surgery and at 9 pm. At 8:00 am and 9:00 pm on the first and second days following surgery, the aroma and almond oils were reapplied. All interventions and measurements were performed by the same researcher. For controlling confounding variables, different group patients were not placed in the same room, and intervention was performed outside of mealtimes to prevent contamination of the aroma fragrances with the smell of food. At the time of the intervention, no adverse reactions related to the aromas were experienced; however, one participant refused to continue, suffering from severe nausea following surgical anesthesia.
Ethics approval and consent
The research proposal was submitted to the institutional review board of the Eulji Medical Center as per the regulations on research ethics and collected data after obtaining approval (Approval no. 2019-04-018). The patients were recruited through public announcements, and the purpose and procedure of the study, the inclusion/exclusion criteria, and the possibility of withdrawing freely at any time was explained. Upon agreeing to participate in the study, the patients were asked to provide written consent.
Data collection
The data were collected at Eulji Medical Center in Daejeon City, South Korea, from June 1 to August 15, 2019. The researcher measured subjective stress, objective stress, pain, and sleep quality three to five times in total on the day of admission, the morning of surgery, immediately after surgery, and on days 1 and 2 after surgery. For protecting personal information, a unique ID was assigned to each patient. After the experiment, $10 gift certificates were offered to the patients in each group.
Data analyses
The collected data were analyzed using SPSS for Windows version 25.0 (IBM Corp., Armonk, NY, USA). The general characteristics of the patients were analyzed by frequency, percentage, and average. Verification of the homogeneity of the patients’ general characteristics was confirmed by ANOVA, x2-test, and Fisher’s exact test. Verification of the homogeneity of the dependent variables of the three groups was analyzed using one-way ANOVA. The groups were also analyzed using ANOVA and repeated measures ANOVA to verify the effects of stress, pain, and quality of sleep before and after the intervention, and a posthoc test was performed using Scheffe’s procedure. Additionally, the effect size was calculated by Cohen’s d formula, and the significance was evaluated with a 95% confidence interval and a significance level less than 5.0%. In this study, per-protocol analysis was performed, and only patients who completed the performance in their assigned groups were analyzed. Missing data were processed and analyzed using listwise deletion; however, no cases were excluded due to missing values.
Results
The general characteristics of the patients and homogeneity verification
There were 69 patients in this study, 23 in each group, and the mean ages were 47.78, 54.57, and 57.96 years in the intervention, placebo, and control groups, respectively. The patients’ subjective stress, objective stress, parasympathetic activity, sympathetic activity, pain, and sleep quality were not significantly different among the three groups; therefore, the three groups were considered to be homogeneous (Table 1).
Table 1Homogeneity test of General Characteristics, Dependent Variables between the Three Groups (N = 69).
Characteristics
Category
Inter. (n = 23)
Plac. (n = 23)
Cont. (n = 23)
X2or F
p
M(SD)or n (%)
M(SD)or n (%)
M(SD)or n (%)
Age (yr)
47.78 (11.72)
54.57 (16.49)
57.96 (12.91)
68.20
.668
Range
26–63
29–80
33–82
Gender
Women
10 (43.5%)
11 (47.8%)
9 (39.1%)
Men
13 (56.5%)
12 (52.2%)
14 (60.9%)
0.35
.838
Job
No
4 (17.4%)
11 (47.8%)
10 (43.5%)
Yes
19 (82.6%)
12 (52.2%)
13 (56.5%)
5.40
.067
Subjective stress
4.04 (1.97)
3.35 (1.92)
3.96 (2.65)
0.68
.511
Objective stress
4.70 (2.12)
4.57 (2.04)
5.09 (2.23)
0.37
.690
Sympathetic nerve activity
4.88 (1.07)
4.46 (1.38)
4.46 (1.13)
0.95
.394
Parasympathetic nerve activity
4.40 (1.09)
4.27 (1.32)
4.23 (1.09)
0.14
.874
Pain
0.91 (1.65)
1.22 (2.06)
1.13 (2.12)
0.15
.863
Sleep quality
49.78 (15.58)
52.09 (13.31)
52.39 (12.79)
0.27
.765
Note. Cont. = Control group; Inter. = Intervention group; Plac. = Placebo group; SD = Standard deviation; Yr = Year.
Verification of the effects of aroma essential oil inhalation
Stress
There was no significant difference in the stress scores between the groups on the day of admission, before surgery, and immediately after surgery. Immediately after the surgery and before the intervention, the subjective stress scores in the intervention, placebo, and control groups were 7.78, 7.30, and 6.96, respectively. After the intervention, the subjective stress scores on the first day after surgery were 1.22, 4.09, and 5.30 in the intervention, placebo, and control groups, respectively, and 0.65, 2.78, and 3.87 on the second day after surgery. Subjective stress was significantly different between the groups on the first (F = 29.24, p < .001) and second day (F = 17.40, p < .001) after surgery, and the effect sizes, 95% confidence interval of the intervention group versus the control group and the intervention group versus the placebo group were −2.40 (−3.16/−1.64) and −1.49 (−2.14/−0.83) on the first day after surgery, and 1.86 (−2.56/–1.17) and −1.17 (−1.79/–0.54) on the second day after surgery, respectively (Table 2). There was a significant group-by-time interaction effect (F = 7.43, p < .001).
Table 2Comparison of Stress, Pain, Sleep Quality between the Three Grou ps (N = 69).
Variables
Inter. G (n = 23)
Plac.G (n = 23)
Cont.G (n = 23)
Inter vs.Plac
Inter vs.Cont
F∗
p
F(p)∗∗
Mean ± SD (CI 95%)
Mean ± SD (CI 95%)
Mean ± SD (CI 95%)
Effect Size
Effect Size
Subjective stress
Dadm
4.04 ± 1.97 4.04 (3.19–4.89)
3.35 ± 1.92 3.35 (2.52–4.18)
3.96 ± 2.65 3.96 (2.81–5.10)
0.68
.511
Time 64.34 (< .001) G∗T 7.43 (< .001) Group 6.83 (.002)
Dpreop
4.96 ± 2.402 4.96 (3.92–6.00)
4.96 ± 2.55 4.96 (3.85–6.06)
4.83 ± 2.04 4.83 (3.95–5.71)
0.46
.460
Dpostop
7.78 ± 1.59 7.78 (7.09–8.47)
7.30 ± 2.03 7.30 (6.43–8.18)
6.96 ± 1.94 6.96 (6.12–7.80)
1.14
.327
Dpostop#1 (post test)
1.22 ± 1.68a 1.22 (0.49–1.94)
4.09 ± 2.15b 4.09 (3.16–5.02)
5.30 ± 1.72b 5.30 (4.56–6.05)
1.49
2.40
29.24
<.001
Dpostop#2 (post test)
0.65 ± 1.43a 0.65 (0.03–1.27)
2.78 ± 2.15b 2.78 (1.85–3.71)
3.87 ± 1.98b 3.87 (3.01–4.73)
1.17
1.86
17.40
<.001
Objective stress
Dadm
4.70 ± 2.12 4.70 (3.78–5.61)
4.57 ± 2.04 4.57 (3.68–5.45)
5.09 ± 2.23 5.09 (4.12–6.05)
0.37
.690
Time 0.06 (.938) G∗T2.70 (.034) Group 6.47 (.003)
Dpostop#1 (post test)
3.61 ± 1.41a 3.61 (3.00–4.22)
5.04 ± 1.67b 5.04 (4.32–5.76)
5.61 ± 2.35b 5.61 (4.59–6.62)
0.93
1.03
7.14
.002
Dpostop#2 (post test)
3.13 ± 1.10a 3.13 (2.65–3.61)
5.30 ± 2.46b 5.30 (4.24–6.37)
5.61 ± 2.57b 5.61 (4.50–6.72)
1.14
1.25
9.09
<.001
Sympathetic nerve activity
Dadm
4.88 ± 1.07 4.88 (4.42–5.35)
4.46 ± 1.38 4.46 (3.87–5.06)
4.46 ± 1.13 4.46 (3.97–4.95)
0.95
.394
Time 0.50 (.607) G∗T 0.74 (.566) Group 4.16 (.020)
Dpostop#1 (post test)
5.17 ± 0.99a 5.17 (4.74–5.60)
4.52 ± 0.92b 4.52 (4.12–4.92)
4.13 ± 1.07ab 4.13 (3.68–4.59)
6.41
.003
Dpostop#2 (post test)
4.85 ± 0.63 4.85 (4.57–5.12)
4.40 ± 1.37 4.40 (3.81–4.99)
4.22 ± 1.29 4.22 (3.66–4.77)
1.85
.165
Parasympathetic nerve activity
Dadm
4.40 ± 1.09 4.40 (3.93–4.88)
4.27 ± 1.32 4.27 (3.70–4.84)
4.24 ± 1.09 4.24 (3.77–4.70)
0.14
.874
Time 0.18 (.840) G∗T 2.65 (.036) Group 4.66 (.013)
Dpostop#1 (post test)
4.98 ± 1.03a 4.98 (4.54–5.43)
4.22 ± 1.04b 4.22 (3.77–4.67)
3.96 ± 1.44b 3.96 (3.34–4.58)
4.63
.013
Dpostop#2 (post test)
5.07 ± 0.71a 5.07 (4.77–5.39)
4.00 ± 1.35b 4.00 (3.42–4.59)
3.88 ± 1.47b 3.88 (3.24–4.51)
6.70
.002
Pain
Dadm
0.91 ± 1.65 0.91 (0.2–1.63)
1.22 ± 2.07 1.22 (0.32–2.11)
1.13 ± 2.12 1.13 (0.21–2.05)
0.15
.863
Time 405.46 (<.001) G∗T 8.74 (<.001) Group16.35 (<.001)
Dpreop
0.48 ± 1.12 0.48 (–0.01–0.96)
0.65 ± 1.97 0.65 (–0.20–1.50)
0.39 ± 0.94 0.39 (–0.02–0.80)
0.20
.817
Dpostop
9.70 ± 1.02 9.70 (9.25–10.14)
9.91 ± 0.42 9.91 (9.73–10.09)
9.39 ± 1.25 9.39 (8.48–10.30)
0.84
.436
Dpostop#1 (post test)
2.35 ± 1.30a 2.35 (1.79–2.91)
5.04 ± 1.85b 5.04 (4.25–5.84)
5.52 ± 1.56b 5.52 (4.85–6.20)
1.68
2.21
26.79
<.001
Dpostop#2 (post test)
0.57 ± 0.90a 0.57 (0.18–0.95)
3.74 ± 1.91b 3.74 (2.91–4.57)
3.43 ± 1.67b 3.43 (2.71–4.16)
2.12
2.13
29.14
<.001
Frequency of analgesics administration
1.83 ± 0.94 1.83 (1.42–2.23)
3.39 ± 0.78 3.39 (3.05–3.72)
3.48 ± 1.08 3.48 (3.01–3.95)
22.43
<.001
Sleep quality
Dadm
49.78 ± 13.58 49.78 (43.91–55.65)
52.09 ± 11.31 52.09 (46.33–57.84)
52.30 ± 11.85 52.30 (47.18–57.43)
0.27
.765
Time 57.60 (<.001) G∗T 5.23 (<.001) Group 0.65 (.528)
Dpreop
42.35 ± 13.25 42.35 (36.62–48.08)
50.17 ± 15.47 50.17 (43.48–56.87)
51.26 ± 15.66 51.26 (44.49–58.03)
2.47
.092
Dpostop#1 (post test)
57.00 ± 7.37 57.00 (53.81–60.19)
56.43 ± 5.77 56.43 (53.94–58.93)
53.52 ± 4.24 53.52 (51.69–55.36)
0.08
0.58
2.28
.111
Dpostop#2 (post test)
71.35 ± 4.10a 71.35 (69.58–73.12)
65.09 ± 4.16b 65.09 (63.29–66.88)
59.00 ± 8.11c 59.00 (55.49–62.51)
1.52
1.92
26.36
<.001
Note. CI= Confidence Interval; Cont. = Control group; Dadm = admission date; Dpostop = after surgery on the day of operation; Dpostop#1 = 1st day after surgery; Dpostop#2 = 2nd day after surgery; Dpreop = before surgery on the day of operation; F∗ = ANOVA; F∗∗ = Repeated measurement ANOVA; Inter. = Intervention group; Mean ±SD = Mean ± Standard Deviation; Plac. = Placebo group.
Means for each group with different superscript(a,b) indicate a significant difference (Scheffe’ test; p<.05).
There was no significant difference in objective stress on the day of admission, but there were significant differences between the groups on the first day (F = 7.14, p = .002) and second day (F = 9.09, p < .001) after surgery. The effect sizes, 95% confidence interval of the intervention versus the control group and the intervention versus placebo group were −1.03 (−1.65/–0.42) and −0.93 (−1.53/–0.32) on the first day after surgery, and −1.25 (−1.89/–0.62) and −1.14 (−1.76/–0.52) on the second day after surgery, respectively. There was a significant group-by-time interaction effect (F = 2.70, p < .034).
There was no significant group-by-time interaction effect regarding sympathetic activity (F = 0.74, p = .566); however, there was a significant group-by-time interaction effect concerning parasympathetic nerve activity (F = 2.65, p = .036) (Table 2).
Pain
The patients’ immediate pain after surgery was 9.70, 9.91, and 9.39 in the intervention, placebo, and control groups, respectively; there was no significant difference. Pain on the first day after surgery was 2.35, 5.04, and 5.52 in the intervention, placebo, and control groups, respectively; there were significant differences between the groups (F = 26.79, p < .001). Pain on the second day after surgery was 0.57, 3.74, and 3.43 in the intervention, placebo, and control groups, respectively; there were significant differences between the groups (F = 29.14, p < .001). There was also a significant group-by-time interaction effect (F = 8.74, p < .001). Furthermore, there was a significant difference between the groups regarding the frequency of analgesics administered (F = 22.43, p < .001). The effect sizes, 95% confidence interval of the intervention versus the control group and the intervention versus placebo group were −2.21 (−2.94/–1.47) and −1.68 (−2.36/–1.01) on the first day after surgery, and −2.13 (−2.86/–1.41) and −2.12 (−2.85/–1.40) on the second day after surgery, respectively (Table 2).
Sleep quality
There were no significant differences in sleep quality among the groups before and on the first day after surgery. The quality of sleep improved in all three groups on the day after surgery and two days after surgery; however, the levels of improvement exhibited by the placebo and control groups were lower than the intervention group, with there being a significant difference in sleep quality on the second day after surgery (F = 26.36, p < .001). There was also a significant group-by-time interaction effect (F = 5.23, p < .001) (Table 2). The effect sizes, 95% confidence interval of the intervention versus the control group and the intervention versus placebo group were 1.92 (1.22/2.62) and 1.52 (0.86/2.17), respectively.
Discussion
As the incidence of gallbladder disease increases, the number of laparoscopic cholecystectomies increases. Despite the stress, pain, and poor sleep quality that occur after such procedures, prior to this study, there had been no intervention research on laparoscopic cholecystectomy postoperative discomforts, hence the necessity for this study. This study involved men and women participants of various ages. The aim was to reduce the stress, pain, and deterioration of sleep quality experienced by patients following laparoscopic cholecystectomy by applying an aroma essential oil inhalation method that was nonrepulsive, safe, and effective.
Regarding stress, the autonomic nervous system is distributed in internal organs and blood vessels, regulates vital functions, and is composed of sympathetic and parasympathetic nerves [
]. When the sympathetic nerve is excited in response to a sudden environmental change, phenomena such as an increase in blood pressure and an increase in heart rate occur, and the parasympathetic nerve plays a role in stabilizing the body [
]. The aromatherapy essential oil used in this study comprised marjoram, neroli, and ylang-ylang, which affect the parasympathetic nervous system, and lavender, which maintains the balance of the autonomic nervous system [
]. This blended oil is understood to have helped relieve stress and increase the activity of parasympathetic nerves in the patients undergoing cholecystectomy.
The results in this study agree with the results of prior studies on aromatherapy examining the stress relief of coronary angiography patients [
Effects of aromatherapy on stress responses, autonomic nervous system Activity and blood pressure in the patients undergoing coronary angiography: a non-randomized controlled trial.
]. Furthermore, in studies on the general population, lavender has been found to enhance parasympathetic activity and have significant effects on stress relief and sleep [
]. Thus, based on the results of this study, the inhalation of essential oils blended with lavender, ylang-ylang, marjoram, and neroli is considered to be effective in relieving stress, enhancing parasympathetic nerve activity, and helping to calm people.
In this study, the analysis of the effect of aromatherapy on the pain experienced by patients following laparoscopic cholecystectomy identified significant differences between the intervention, placebo, and control groups. The patients in the intervention group experienced significantly lower pain than the patients in the other groups. In the 48 hours after surgery, the number of additional pain control measures employed besides regular analgesics was significantly lower in the intervention group than in the other groups. These results are consistent with the results of studies examining lavender, geranium, and peppermint oil hand massages given to vascular dialysis patients receiving arteriovenous fistula puncture treatment [
Effects of 10% lidocaine spray and aroma hand massage on pain, anxiety, blood pressure, and pulse during arteriovenous fistula needling in hemodialysis patients.
The effect of topical application of lavender essential oil on the intensity of pain caused by the insertion of dialysis needles in hemodialysis patients: a randomized clinical trial.
]. Aromatherapy was found to alleviate pain in all of the studies. The findings in this study are considered to be the result of applying essential oils to calm patients. Thus, it appears clear that aromatherapy involving the inhalation of essential oils is effective in reducing pain.
Previous studies have shown the positive effects of aromatherapy on sleep quality. These studies have examined elderly patients [
], there was no significant improvement in the quality of sleep. In sum, although aromatherapy has not been found effective in every study, several studies have identified a positive effect on sleep. In this study, the patients’ subjective sleep quality increased after surgery, with the intervention group demonstrating a significantly higher quality of sleep. Thus, this study adds to the research demonstrating the positive effect of aromatherapy on sleep.
There are some limitations of this research. Despite the patients and the outcome measurer not being informed of the groups to which they were assigned, the essential oil used for the aromatherapy released a scent; therefore, the experiment could not be completely blind. This may have lead to performance bias. Additionally, since there were few research participants, there is a limit to the external validity of generalizing the research results. Thus, to verify the effectiveness of aroma essential oil inhalation in alleviating stress, reducing pain, and improving sleep, further studies examining various aroma essential oils and various blending ratios to dependent variables, as well as analyses using a variety of indicators, are recommended.
Conclusion
The results of this study showed that inhalation of a blended oil comprising lavender, ylang-ylang, marjoram, and neroli for two days following surgery relieves stress, alleviates pain, and is helpful for sleep. Thus, nursing intervention using a blended aromatherapy oil inhalation method will benefit postoperative patients by improving recovery times, thereby expediting their return to daily life.
Funding
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT and Future Planning (NRF-2015R1A1A3A04001441).
Data availability
The data for this study are available from the corresponding author on reasonable request.
Conflict of interest
The authors declare there is no conflict of interest.
Acknowledgments
The researchers of this study express their gratitude to the participants despite the difficulties of being hospitalized and undergoing surgery. Thank you, all of the patients involved in the study who provided their signed informed consent.
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