Acupuncture on Yintang Point Decreases Preoperative Anxiety

Abstract

Objectives:

The aim of this study was to investigate the effect of ear-press needle acupuncture on Yintang point for preoperative anxiety.

Design:

This was a prospective, randomized, single-blind, controlled study.

Settings/location:

The study setting was the Department of Anesthesiology in Ankara Training and Research Hospital of Ministry of Health, Ankara, Turkey.

Subjects:

The study comprised 52 adult surgical patients.

Interventions:

A single, 20-minute session of single-point acupuncture was applied on Yintang (acupuncture group) or sham point (sham acupuncture group).

Outcome measures:

The efficacy of acupuncture was evaluated by means of the changes in bispectral index (BIS) and STAI (State-Trait Anxiety Index).

Results:

BIS values in the acupuncture group were significantly lower than in the sham group in all time intervals (p<0.0042). BIS values were lower than baseline in the study group during the entire study period (p<0.0004) while no such effect has been observed in the sham group (p>0.0004). Mean values of state anxiety (STAI-S) decreased after acupuncture in the study group (p=0,018), while no change was observed in trait anxiety (STAI-T) (p=0.156). Patients of the sham group showed no change in both parameters (p=0.387 and p=0,116).

Conclusions:

Ear-press needle acupuncture on Yintang point reduces preoperative anxiety in adult surgical patients.

Introduction

P reoperative stress and anxiety is a major problem for anesthesiologists, since the incidence ranges from 11% to 80% among adult surgical patients.¹ It has negative consequences during intraoperative and postoperative periods. Anxiety increases intraoperative and postoperative anesthetic requirements and makes the pain control difficult in the postoperative period.^1,2 High preoperative anxiety is also a risk factor for postoperative anxiety³ and postoperative nausea and vomiting.⁴ Decreasing preoperative anxiety improves preoperative pain attitude and postoperative analgesia,⁵ increases patient satisfaction,⁶ and causes a better recovery.^5,6

Acupuncture is an ancient technique that originated in China thousands of years ago. Studies showed that acupuncture might be a useful technique to treat various conditions as well as anxiety.^7,8

Stimulation of the Yintang point, which is located at the root of the nose, decreases preoperative anxiety in healthy volunteers and surgical patients.^9

–13 Various techniques including acupressure with the thumb,^9,10,13,14 needling,¹¹ and acupressure bead¹² have been used for stimulation of the Yintang point. However, ear-press needle on the Yintang point was not studied for preoperative anxiety until now.

This randomized, controlled study was designed to test the assumption that application of ear-press needles on the Yintang point may have a potential to decrease preoperative anxiety in adult surgical patients.

Materials and Methods

After approval from the ethics committee of Ankara Training and Research Hospital of Ministry of Health and obtaining informed consent of the patients, adult patients who were between the ages of 18 and 65 years and who were undergoing general or regional anesthesia and classified under American Society of Anesthesiologists I-II were included in the study. Patients with major psychiatric problems, and patients who were using anxiolytic, sedative, or psychotropic drugs were excluded. With α of 0.05 and power of 0.85 to detect a 20% difference between groups, a sample size of 52 patients was estimated (26 patients per group). Needling was performed by one of the authors (HVA). The acupuncturist was not blinded to the groups, whereas patients and assessors were blinded.

Patients were divided into two groups based on a computer-generated randomization table:

1. Acupuncture: Yintang (EX HN-3) point, which is located at the root of the nose and between the eyebrows, was used in these patients. This point has been described as having sedative and relaxant properties.¹⁵

2. Sham acupuncture: A nonacupoint, which is located 2 cm lateral to the distal end of the right eyebrow was used in these patients. This was used as a sham point in studies investigating the stimulating effect of the Yintang point on anxiety.^{9,10,12
–14,16,17}

After recording demographic data, patients completed STAI (State-Trait Anxiety Inventory) in the preoperative waiting area. STAI is a commonly used self-report instrument to measure anxiety; it consists of two 20-item portions for state anxiety (STAI-S) and trait anxiety (STAI-T).¹⁸ Then, a disposable bispectral index (BIS) electrode that was attached to a BIS VIEW monitor (Aspect Medical Systems, Newton, MA) was placed on each patient's forehead while patients were in a 30° head-up position. After 3 minutes of rest, median value was recorded as the baseline measurement. Yintang or sham points are then needled. Needles used were disposable ear-press needles (0.22 mm×1.5 mm, Kingli Press Needle, China) (Fig. 1).

FIG. 1.

Ear-press needle.

BIS measurements were recorded at baseline and was repeated every 2 minutes for 20 minutes. At the end of the 20-minute measurement period, the BIS electrode and acupuncture needle was removed. Patients then completed the STAI again.

Statistical analysis

Data analysis was performed by using Statistical Package for Social Sciences (SPSS) version 11.5 software (SPSS Inc., Chicago, IL). The Shapiro-Wilk test was used to test the normality of distribution for continuous variables. Data were expressed as mean±standard deviation or median (minimum–maximum), where applicable. Means were compared by unpaired t-test, while the Mann-Whitney U test was used for the statistical comparison of the median values. Intragroup comparisons were evaluated by paired-samples t-test or Wilcoxon sign rank test, where appropriate. Nominal data were analyzed by Pearson χ² test. A p-value<0.05 was considered statistically significant. However, for all possible multiple comparisons, the Bonferroni correction was applied for controlling Type I error.

Results

Groups were comparable in terms of age, weight, height, and gender distribution (Table 1). Baseline and 0-minute BIS values were comparable between groups (p=0.366 and p=0.574) (Fig. 2). However, BIS values between the second and twentieth minutes were significantly lower in the acupuncture group than in the sham group (p<0.0042) (significant at p<0.0004 with Bonferroni correction). BIS values in the acupuncture group were significantly lower than in baseline values in all measurements except 0 minutes (p<0.0004), whereas no significant differences were found in the sham group (p>0.0004) (significant at p<0.0004 with Bonferroni correction).

FIG. 2.

Changes in BIS (bispectral index) during the study period. *p<0.05 compared to baseline. ¶p<0.05 compared to sham acupuncture.

Table 1.

Demographic and Clinic Data of the Patients

	Acupuncture (n=26)	Sham acupuncture (n=26)	p-Value
Age (years)	38.38±14.61	38.42±14.43	0.992
Weight (kg)	78.96±14.60	72.19±11.14	0.066
Height (cm)	168.70±8.38	166.62±8.94	0.392
Sex (M/F)	16/10	15/11	0.777
GA/RA	15/11	14/12	0.780

GA, general anesthesia; RA, regional anesthesia.

In the acupuncture group, the mean STAI-S value decreased with acupuncture treatment (p=0.018), whereas no change was seen in mean STAI-T value (p=0.156). However, no significant difference was found both in STAI-S and in STAI-T values in the sham group (p=0.387 and p=0.116) (Figs. 3 and 4).

FIG. 3.

Comparison of STAI-S (State-Trait Anxiety Index-State) values in acupuncture and sham groups. *p<0.05 compared to baseline.

FIG. 4.

Comparison of STAI-T (State-Trait Anxiety Index–Trait) values in acupuncture and sham groups.

Discussion

It was determined that ear-press needle acupuncture on the Yintang point decreased preoperative anxiety significantly in adult surgical patients.

Acupuncture and related techniques (acupuncture, acupressure, etc.) are effective for various anxiety conditions. These include dental anxiety,^19,20 anxiety before extracorporeal shock-wave lithotripsy,²¹ and anxiety in prehospital transport settings.²² Acupuncture also decreases preoperative anxiety in children¹² and in parents whose children will undergo surgery.^16,23

In Traditional Chinese Medicine, the Yintang point is indicated for insomnia, agitation, and restlessness.¹⁵ Stimulation of this point leads to an anxiolytic and sedative effect. Two (2) studies by Wang et al. have shown the positive effect of stimulation of ear acupuncture points on anxiety in volunteers and in surgical patients.^24,25 However, stimulation of the Yintang point for preoperative anxiety was first described by Fassoulaki et al.⁹ They reported that acupressure with the thumb for 10 minutes resulted in a decrease in anxiety. Later reports support the use of acupuncture on the Yintang point to decrease preoperative anxiety.^10

–13,16

Assessment of anxiety/sedation can be performed by various methods such as sedation scales (i.e., STAI) and monitoring devices (i.e., BIS). BIS monitoring is based on electroencephalogram (EEG)-derived data and used for monitoring of the depth of anesthesia intraoperatively.²⁶ However, use of BIS is not only limited to the awareness during anesthesia. BIS is a common tool for monitoring sedation in the intensive care unit and sedation during monitored anesthesia care.²⁶ Furthermore, BIS can also be used for the assessment of anxiety in the preoperative settings.^{9,11,12,16,27

–31}

Decreased BIS and STAI values in the present study made the patients calm and more relaxed. This was supported by studies that demonstrated that reductions in BIS and STAI correlated well with anxiolysis.^{27,29,30,31,32} In this way, patients can cope with the preoperative anxiety associated with surgery and anesthesia. Reducing preoperative anxiety leads to less postoperative pain, less postoperative analgesic consumption, and less nausea and vomiting.^4,5,33 Patients with lesser preoperative anxiety also have better surgical outcome and shorter duration of hospitalization.³⁴

The major inconsistency between the present study and the others that used Yintang for preoperative anxiety is the quantity of decrease in anxiety. In the present study of ear-press needle acupuncture, it was found that BIS value decreased from 97.3 to 89.3 at the end of a 20-minute period, while the lowest value was 86.8. However, the lowest BIS value ranged between 35 and 42 in the studies.^9,28,35 Fassoulaki et al. found that the BIS value was decreased from 97 to 47 at the tenth minute.⁹ In another study, the same group detected that the BIS value decreased from 97 to 38 at the tenth minute.²⁸ In Litscher's study, acupressure at the Yintang point caused a reduction in BIS value from 97.4 to 62.9 at the fifth minute.³⁵ However, in all three studies researchers applied acupressure with the thumb. For the present study, an ear-press needle was used and no extra pressure was applied when inserting needle. This may explain the differences between studies. Fortunately, BIS decreases in the present study were statistically significant in all measurement times.

Although acupressure with the thumb has resulted in higher decreases in anxiety levels, the method has several limitations. First, this may not be a feasible technique in busy clinical settings. Applying pressure with a finger for 10 minutes is not an easy task since the practitioner begins to get tired after a while. It also may not be possible for most departments to assign a person to apply acupressure to each patient for long periods of time. Second, it is obvious that a standardized intensity of stimulation cannot be guarenteed in this way. Wang et al. have used an acupressure bead with a self-adhesive tape to create a “continuous standardized pressure of 1.3 psi as measured by a tonometer” to overwhelm this issue.¹² However, they could not find a significant difference in BIS values and STAI values either between groups or within groups both in adults and children, although STAI was decreased.^12,16 It is therefore suggested that the use of an ear-press needle offers an valuable choice to stimulate the Yintang point. Although it was developed for ear acupuncture, application of ear-press needles on body acupoints has been used with success in studies.^36,37 Use of ear-press needles take only several seconds to apply and does not require an experienced staff. The method provides time and manpower in anesthesia departments with heavy workload and health care provider shortage, which is a great problem even in developed countries.³⁸

In the current study, both BIS and STAI-S values decreased significantly after the stimulation of the Yintang point. Other investigators also found that the change in both EEG-derived data (i.e., BIS and A-line autoregressive index [AAI]) and verbal stress scale (VSS) values were in parallel to each other in acupuncture (Yintang) groups.^10,17,28 However, a distinction was noted between the results of sedation scales and monitoring devices in some studies. Wang et al. have detected a decrease in STAI (44 pre, 37 post) and State-Trait Anxiety Inventory for Children (−9%) scores, while no change was seen in BIS values (95 pre, 96 post).^12,16 Litscher et al. also have shown that VSS decreased with the stimulation of both Yintang and sham acupoints, while BIS (97.4 pre, 62.9 post) and spectral-edge frequency decreased only after the stimulation of the Yintang point.³⁵ Although the reason for this was not fully understood, it might be due to several reasons including differences in stimulation techniques (acupressure with thumb, and acupressure with bead), subject populations (volunteers, preoperative patients, and preoperative children's parents), and assessment methods (AAI, BIS, and VSS).

In the present study, a significant decrease was found in STAI-S value, while there was no change in STAI-T. This is not surprising, because STAI-T measures trait anxiety, whereas STAI-S measures state anxiety.¹⁸

Cases in the current study were not held in a dark and quiet room as in the study by Cabrini et al., which compared two combinations of acupoints and found a decrease in anxiety both in acupuncture and sham groups.³⁹ The reason for this was to mimic the routine clinical conditions, while the aim was to explore a method that can be used in daily routine. Premedication units in most anesthesia departments are not isolated from noise and lightning. Therefore, to provide an isolated room for the patient would be misleading and cause wrong results.

Conclusions

Acupuncture with ear-press needles on the Yintang point reduces preoperative anxiety in adult surgical patients. This method offers a valuable alternative to pharmacological agents in the management of preoperative anxiety.

Footnotes

Acknowledgments

The authors thank Cansu Kaya for providing illustrations.

Disclosure Statement

No competing financial interests exist.

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