Biological Research for Nursing - Decision on Manuscript ID BRN-ROR-10-02-0007 Title: EvidencethatMusicListening ReducesPreoperativePatients’Anxiety
Abstract
Background. Preoperatively, patients often exhibit fear and anxiety that may
influence the process of induction and recovery from anesthesia. Music is thought to
be an alternative to medication for relief of fear and anxiety.
Objectives.
The purpose of the present study was to explore the feasibility of using heart rate
variability for evaluating the efficacy of music listening to relieve the patients’
anxiety during their stay in the waiting area of the operation room and to compare the
HRV measures with subjective visual analogue scale (VAS) scores.
Methods. In total, 140 patients were randomly assigned to the experimental group
(n=64) or control group (n=76). The intervention consisted of a 10-min period of
exposure to relaxing music delivered through headphones. Anxiety levels were
measured by the VAS (a ten-point scale) and 5 min of monitoring of HRV before and
after the music intervention.
Results. The music group demonstrated significant reductions in VAS scores, mean
heart rate, low-frequency HRV, and low- to high-frequency ratio, and an increase in
high-frequency HRV, while patients in the control group showed no changes.
subjectiveresultsofpatient’sVAS anxiety scores were consistent with the objective results of HRV parameters.
Conclusions. Listening to music can significantly lower the anxiety levels of patients
before surgery. The frequency-domain parameters of HRV can be indicators for
monitoring the change in anxiety level of preoperative patients.
Introduction
Every year, 3.5 million patients receive surgery in Taiwan (Department of
Health, 2009). The most common emotion felt by patients before surgery is anxiety
about the unknown (Leach, Zernike, & Tanner, 2000; Rosén, Svensson, & Nillson,
2008). An unfamiliar environment, dependence on strangers, separation from family
and friends (Gillen, Biley, & Allen, 2008), a perceived or actual physical risk,
possible postoperative complications, and even the threat of death are factors that may
cause patients to feel anxious in the waiting area before surgery (Mitchell, 2003). The
waiting period is also the time during which patients are most likely to imagine any
potential danger they may face (Cooke, Chaboyer, Schluter, & Hiratos, 2005; Haun,
Mainous, & Looney, 2001). To date there has been little research conducted with the
Taiwanese on their propensity to preoperative anxiety.
Anxiety can affectan individual’scognitiveabilitiesand causeboth mentaland physical discomfort (Vaughn, Wichowski, & Bosworth, 2007). This, in turn, can
increase postoperative pain, prolong postoperative recovery, and increase analgesic
requirements. (Ozalp, Sarioglu, Tuncel, Aslan, & Kadiogullari, 2003; Katz et al.,
2005; Rosén et al., 2008). Even though doctors usually provide prescribed anxiolytics
Research also indicates that patients do not want excessive medication to lower their
anxiety, but would rather listen to music or read (Hyde, Bryden, & Asbury, 1998).
Music has been used since ancient times to influence human health (Nilsson,
2008). The common theory to explain the anxiety and stress-reducing effect of music
is that music acts as a distracter, focusing the patient’s attention away from negative
stimuli to something pleasant and encouraging (Mitchell, 2003; Nilsson, 2008). Music involvespatient’smind with something familiar and soothing, which allows a patient to escape into his or her “own world.”Patients can focus their awareness on the music
to aid relaxation. (Thorgaard et al., 2005; White, 2000; White, 2001). Research
comparing music and diazepam (Berbel, Moix, & Quintana, 2007) showed that music
had calming effects that could lower anxiety and relax patients before surgery.
Therefore, music is an effective non-invasive method to reduce anxiety (Buffum et al.,
2006; Nilsson,2008).
Some have suggested that therapeutic music should have a slow tempo, low
pitch, regular rhythm, and pleasing harmonics, and consist of string, flute, and piano
selections (Nilsson, 2008; Pelletier, 2004). The genre and the duration of the soothing
music did not seem to influence the effectiveness of music intervention. These results
anxiety during short waiting periods and a Cochrane review that explored the effects
of music on pain (Cooke, Chaboyer, & Hiratos, 2005).
Most of the studies measured anxiety by subjective scales,such as the
State-Trait Anxiety Inventory (STAI) or visual analog scale (VAS) (Mitchell, 2003; Nilson,
2008). Their validity was limited by theclients’self-reporting ability and results were
influenced by personal preference of music (Mitchell, 2003). As the medical
profession has considerable concern about patient safety, effective anesthesia and
what patients want, objective indicators are needed to monitor the level of anxiety in
assessing and caring for patients.
In addition, though many studies showed that listening to music is effective, the
physiological indicators were not consistent (Dijkstra, Pieterse, & Pruyn, 2006).
Previous studies have also shown that anxiety scores were not related to blood
pressure (Hamel, 2001; Yung, Chiu-Kam, Lau, & Chan, 2003), breathing (Buffum et
al., 2006; Yung, Chui-Kam, French, & Chan, 2002; Taylor-Piliae, & Chair, 2002),
electrodermal activity, or serum levels of cortisol and adrenaline (Wang, Kulkarni,
Dolev, & Kain, 2002).
The purpose of this study was to explore the feasibility of using heart rate
patients during their stay in the waiting area of the operating theater, and to compare
the HR variability measures with subjective visual analogue scale (VAS) scores.
Methods
Research Design and Setting
The present study was a randomized, clinical study that took place in the waiting
area of an operating theater of a teaching hospital in northern Taiwan. There are ten
rooms in this operating theater and the average number of surgeries is 1000/month.
Patients are admitted to the hospital at least one day before the day of surgery. They
are sent to the waiting area of the operating theater 30 min before the scheduled
surgery time. Premedication will be given when they enter the operating room. The
waiting room is nearly independent but not completely isolated from the nursing
station. Its size is 1260 x 390 cm, and it can hold eight patients simultaneously. The
temperature of the room was maintained at 19~21° C.
Sampling and sample size
Patients who were sent to the waiting area between 07:00 and 16:00 were
recruited for enrollment. The inclusion criteria were that the patient: (1) was
conscious and aged 20~65 years, (2) had not consumed any medications for
hypertension or heart disease, caffeine, sedatives, or operative premedication, (3) had
disease, (4) stayed at least 25 min in the waiting area, and (5) was willing to
participate in the study and signed an informed consent form.
Group assignment was done by dividing subjects’by birthday according to even
(experimental group) or odd days (control group). Sample size was determined by the
assistance of G power software (Grant Devilly, Vistoria, Australia). We set alpha as
0.05, the effect size (t) for heart rate variability as 0.3 (small), and the power as 0.8 for
our two group repeated level of two statistical procedures. A resulting sample size of
55 for both groups was obtained. Considering an attrition rate of 20% due to short
stays in the waiting area, we decided on an expected sample size of 70 for both groups.
Intervention
The patients in the experimental group listened to music via an MP3 player
(Ergotech, ET-U31P, Taoyuan, Taiwan), while patients in the control group did not
listen to music. Subjects were provided with a list of five kinds of music of 10 min
duration to choose from. All five kinds of music were light music such as folk songs
or pop music, played at a tempo of 60~80 beats per minute and a volume of 50~55 db.
Measurements
In our study, we used a visual analog scale (VAS) instead of State-Trait Anxiety
Inventory (STAI) which has been used in most studies of anxiety. This decision was
This could cause unnecessary strain for patients waiting for surgery in the waiting
area of the operating room and could make them more nervous. On the other hand, the
VAS takes only five seconds for a patient to express his/her anxiety level. Second, a
patient can remain lying down and still respond to the VAS, while the patient might
need to change his/her posture to fill out the STAI questionnaire. Third, the VAS was
routinely used in this hospital for pain and anxiety assessment. Subjects were used to
responding to it.
The VAS is a ten-centimeter horizontal line marked by vertical lines at
one-centimeter intervals to construct a scale. To use in measuring anxiety, subjects were
asked to say a number or indicate with their finger to give the score from 0 (calm) to
10 (very anxious). It was reported that the VAS was significantly correlated with
hospital anxiety (r= 0.28) (Ledowski, Bein, Hanss, Tonner, Roller, & Scholz, 2005)
and STAI (r=0.5-0.6) (Abdul-Latif, Putland, McCluskey, Meadows, & Remington,
2001; Clan, 2004).
Heart rate was measured by a CheckMyHeart handheld HRV device (DailyCare
BioMedical, Chungli, Taiwan). It is a handheld limb lead EKG (lead I) recorder with
HR variability analytical software. To measure HR, the researchers placed the sensor on theradialareaofthepatient’sforearm for5 min.Participants were asked not to move around to ensure the quality of the readings. According to the user’smanual,the
CheckMyHeart is CE certified (Conformite Europeenne) and has passed
electromagnetic interference and compatibility tests. Its sampling frequency is 250
samples/sec. The measurement heart rate range is 45-186 bpm and ST segment -3 to
+3 mm, and operates stably at temperature of 50℉-104℉ (10℃-40℃) and humidity
of 25%-95%. It has been used in previous clinical studies of HR variability (Peng,
Koo, & Yu, 2009; Wen, Chung-Kwe, Yang, & Yang, 2007).
The heart rate data was analyzed by the CheckMyHeart software and provided
parameters of heart rate variability. In the time-domain analysis, the original
normal-to-normal intervals (NNIs) were subjected to a statistical analysis, and the variables
included the mean of the NNIs (mean NNI), the standard deviation of the NNIs
(SDNN), and the root mean square of successive differences in the NNIs (rMSSD).
Prior literature has established that when an individual feels anxiety or pressure, these
indicators decrease (Malik et al. 1996).
In the frequency-domain, a power spectral density analysis was utilized to
analyze the distribution of HR variability at different frequencies. The total power is a
short-term estimate of the total power of the spectral density in the range of
frequencies between 0 and 0.4 Hz representing the overall activity of the autonomic
nervous system (ANS). Very low frequencies (VLFs; frequencies between 0.0033 and
frequencies (LFs; frequencies between 0.04 and 0.15 Hz) reflect mixed sympathetic
and parasympathetic activities. High frequencies (HFs; frequencies between 0.15 and
0.4 Hz) reflect parasympathetic activity. Deep, even breathing activates the
parasympathetic and raises the HF amplitude (Malik et al. 1996; Musselman, Evans,
& Nemeroff, 1998; Niskanen, Tarvainen, Ranta-aho, & Karjalainen, 2004). High
values of the low-to high (LF/HF) ratio indicate a dominance of sympathetic activity
while low values indicate a dominance of parasympathetic activity. Activation of the
sympathetic nerves, as happens in anxiety, can cause the HR to increase, total power
and high frequencies to decrease, and low frequencies and the low-to-high ratio to
increase (Kamath & Fallen, 1993).
Data Collection Process
The research was approved by the Institutional Review Board of the study
setting (approved code: CRC-03-09-07). The researcher (KJL) checked the operating
schedule and met the potential participants in the waiting area of the operating theater.
After an eligible participant entered the waiting room, the researcher explained the
purpose and process of the study, helped the patient fill out a consent form, let the
patient lie down on the gurney, and closed the curtains. After 5 min of rest, the VAS
and 5-min HR were measured. Then, subjects of the experimental group listened to a
measured after the music session was finished. Subjects in the control group received
the VAS and heart rate measurements by the researcher at a 10-min interval without a
music intervention.
Statistical Analysis
Data was first examined for completeness. Incomplete data or data with too
many noise signals were deleted for data processing. Data analysis was performed
with SPSS 15.0 (SPSS, Chicago, IL). The major statistical procedures applied were
descriptive statistics, the Chi-squared test,independentStudent’stest, and paired
t-test. If data was not normally distributed, nonparametric statistical procedure was
applied. A value of p< 0.05 was taken as statistically significant.
Results
Between September and November 2009, 185 patients were contacted and 161
were enrolled in the study. Of these, six were unable to complete the study because
they were sent to the operating suite before the 10-min of music or rest was finished,
four refused the second measurement, and 11 were deleted due to poor EKG
recording (incomplete or too many noise signals). Finally, there were 76 and 64
subjects in experimental group and control group, respectively, that provided useful
There were no significant differences between the experimental and control group in
terms of demographics. The average waiting time for the 140 participants was 27 min.
Seventy percent to 80% of patients received general anesthesia, and 11%~15%
underwent spinal anesthesia. The majority of subjects received obstetric and
gynecological surgery, followed by orthopedic surgery. There were no significant
differences between the two groups in age, gender, waiting time, methods of
anesthesia, or types of surgery (Table 1).
Pre-surgical Anxiety
The VAS scores in both groups before and after music intervention are listed in
Table 2, and the HR variability (HRV) data in both groups before and after music
intervention is listed in Table 3.
According to the VAS scores, the initial mean anxiety level of all participants
was 3.4±2.7. The mean anxiety levels of the experimental and control groups were
3.5± 2.9 and 3.2± 2.5, respectively, and the difference was not significant (t=.61,
p=.54, see Table 2). The mean HR of the subjects was 72.7±11.6 beats/min (bpm).
There were no significant differences in mean HR, mean NNI, SDNN, rMSSD, total
power, %LF, %HF, or the LF/HF ratio between the two groups (Table 3).
The VAS scores in both groups before and after music intervention are listed in
Table 2. After listening to music, the mean VAS scores of the experimental group was
decreased and the difference was statistically significant (3.5±2.9 vs. 2.8±2.3, p <
0.001). Comparing the VAS score changes in the control group, the difference was
not statistically significant (3.2±2.5 vs. 3.3±2.4, p > 0.05).
The HR variability (HRV) data in both groups before and after music
intervention are listed in Table 3. After listening to music, the heart rate of the
experimental group was also decreased and the difference was statistically significant
(73.1±10.7 vs. 72±10.6 bpm, p < 0.001). In terms of HRV parameters, the mean NNI
significantly increased (p < 0.001), while SDNN, and rMSSD did not exhibit
significant changes. Percent of low frequency (%LF) and the low-to-high ratio
became significantly smaller after listening to music (p < 0.001), the percent of high
frequency (%HF) showed a significant increase (39.5±17.3 vs. 46.1±19.3, p < 0.001),
while the total power did not exhibit a significant change. Compared to changes in
HRV data at 10-min intervals in the control group, none of the differences were
statistically significant (p>.05).
Table 4 shows the changes between the pre- and post-test measures of the
experimental and control groups. The mean difference in the VAS scores for the
difference was statistically significant (p < 0.001). Additionally, the decrease in the
HR was significantly greater in the experimental group (1.1±2.3 vs.0.3±1.5 bpm, p =
0.02). In terms of HRV parameters, the change in the mean NNI for the experimental
group was significantly higher than that of the control group (p = 0.046). However,
changes in the other parameters, including SDNN and rMSSD were not significant.
Changes in the total power and low-to-high ratio were not significant between the two
groups, but changes in %LFs and %HFs were (Table 4). Taken together, the change in
anxiety levels measured by both the subjective and objective indicators in the
experimental group between the pre- and post-test periods were significantly higher
than those of the control group.
The Influence of Personal Differences on the Effect of Listening to Music
In the music intervention group, personal differences on the pre- and post-test
mean difference in anxiety scores were examined. The results showed that no
demographic background factor such as age, gender, anesthesia type, surgery type, or
surgical experience had a significant influence on changes in anxiety level.
Discussion
In this study, the VAS level of the experimental group was reduced after the
(Table 2). The mean difference in the VAS score for the experimental group was
significantly greater than that of the control group (Table 4). This finding was
consistent with previous findings (Gillen et al., 2008), demonstrating the
anxiety-relieving effect of music intervention on pre-surgical patients in waiting area of
operating theater.
The anxiety-reliving effect was also reflected in the change in heart rates and
part of heart rate variability parameters (Table 3, 4). The HR of the experimental
group had significantly decreased after the music intervention. The mean difference in
the HR in the experimental group was also significantly greater than that of the
control group (p < 0.02). This was consistent with findings of past studies (Bringman,
Giesecke, Thorne, & Bringman, 2009; Yung et al., 2003).
In our frequency-domain parameters of HR variability, low frequency and the
low-to-high ratio of the experimental group showed significant decreases after the
musical intervention, while the high frequency exhibited a significant increase (Table
3). Sheps and Sheffield (2001) stated that anxiety increases the activity of sympathetic
nerves and decreases the activity of parasympathetic nerves, resulting in increased
low frequency HR variability and lowered high frequency HR variability. Thus our
parasympathetic nerves after listening to music. In contrast, the HR variability
parameters in the control group showed no significant changes (Table 3).
Chiu, Lin, Kuo, Chiang, and Hsu (2003) used an HRV analysis to evaluate the
anxiety of 68 pre-procedure subjects, and found that low frequency and the
low-to-high ratio significantly decreased in patients who received music therapy. They also
found that the HFs significantly increased, consistent with our findings. Ledowski et
al. (2005) compared the anxiety level of 50 patients waiting for surgery with healthy
individuals, and found thatthepatients’total power, low frequency, and high
frequency were all lower than those of healthy individuals, indicating the less heart
rate variability in anxious patients.
In terms of the time domain of HR variability parameters, the mean changes in
the SDNN, and rMSSD were not significant. This phenomena indicates that 10 min of
music listening did not cause significant changes in the scales of the variations, but
the frequency of variation presented a significant change. In other words, the
time-domain parameters were not as sensitive as frequency-time-domain parameters for
indicating changes in anxiety levels of patients preoperatively.
Our study confirms the immediate effect of music intervention for anxiety
reduction. However, the duration of this effect is unclear. It was reported that post
the use of analgesics (Nilsson, 2008). Future studies need to determine if lowering the
levels of anxiety in the preoperative patient has any lasting effect on outcomes during
the intraoperative and postoperative stages. Using objective measurements such as
HR variability evaluation, investigating the anxiety levels of patients intraoperatively
and immediately post-operation becomes possible.
Limitations of this study are as follows: Both raters and subjects were not
blinded, which may introduce bias. However, consistent results demonstrated by
objective HR variability data may help eliminate the Hawthorn effect. In addition,
subjects in the control group did not wear headphones as subjects in the experimental
group did. Further study needs to distinguish the effect of wearing headphones from
the effect of music intervention for relieving anxiety.
Conclusions
Listening to music is effective for reducing the anxiety of preoperative patients.
Patient anxiety can be indicated by a decrease in VAS scores, a decrease in the HR,
and a decrease in the low- and an increase in the high-frequency parameters of HR
variability. With an HR variability evaluation as objective measurement, this can also
be considered for assessing the impact of patients’preoperative anxiety on induction
and recovery. In addition, nurses can become more sensitive at assessing patients’
Effective interventions such as music listening can be delivered in a more timely
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