INTRODUCTION:

Approximately 71% of critically ill patients receive Mechanical ventilation.¹ Patients undergoing mechanical ventilator support manifest discomforting symptoms such as pain, dyspnea, anxiety and agitation². Psychological symptoms arise as a result of inability to communicate, family absence and ICU alarm sounds, frequent procedures on the patient and weaning from the ventilator.³ Anxiety in critically ill patients has been reported with an incidence ranging from 30.8%⁴ to 80%⁵. Anxiety greatly affects psychological well-being and physiologic stability of a person. It becomes graver among critically ill patients and patients on mechanical ventilator. The incidence of agitation in critically ill patients is reported from 16% to 71%.^{6,7 ,8} Agitation is a clinical manifestation in response to pain commonly occurring ICU and among patients on ventilator which may occur in isolation, or accompany extreme anxiety⁹, delirium¹⁰ or brain dysfunction.¹¹ Nature based sounds denote to the sounds which are already existing in the nature. They could result from natural phenomena such as wind, rain, ocean, river, birds, and animals’ sounds. Natural environments have been found to be restorative effects on health by inducing positive emotional states and sustained attention.¹² Kaur A et al¹³estimated the effect of nature-based sounds on agitation and anxiety of ICU patients. The result indicated that the means posttest agitation (17.33+01.29) and anxiety (17.97+06.10) scores of patients in intervention group were significantly lower (p≤0.05) than the mean posttest agitation (20.90+02.51) and anxiety (30.77+04.75) scores of patients in control group. Seifi L et al compared the effects of benson muscle relaxation and nature sounds on fatigue among heart failure patients (n=105) using a randomized block design. Results indicated that Benson muscle relaxation and nature sounds significantly reduced fatigue among those patients¹⁴. Aghaie B et al¹⁵ in his RCT demonstrated that group exposed to nature-based sounds had significantly lower anxiety (p<0.002) and agitation (p<0.001) levels than those who didn’t hear those sounds.

NEED OF THE STUDY:

Patients on mechanical ventilator frequently exhibit anxiety and produce assessment and management challenges for clinicians and nurses. Though drugs may be necessarily administered to during initial stages of agitation and anxiety to make them calm and prevent any injury. However, parallel, intermittent and adjunctive use of non-pharmacological interventions with sedatives may magnify the effects of and reduce the dosages of drugs in order to get equal effect. Routine use of Complementary therapies can help reduce anxiety¹⁶ (Pun and Dunn, 2007). Therefore, Sedation need not to be given in all cases in order to manage the patient’s anxiety and distress related to mechanical ventilation.

MATERIAL AND METHODS:

The study was undertaken to identify the effect of the nature-based sounds (NBS) on agitation, and anxiety level in patients under mechanical ventilation support and to determine the association between effects of NBS with selected variables of patients.

Research Hypothesis:

H1: There will be a significant difference in post test scores of anxiety in the patients on mechanical ventilator support exposed to nature based sounds than those who were not exposed to nature based sounds at α level of 0.05.

H2: There will be a significant difference in post test scores of agitation in the patients on mechanical ventilator support exposed to nature based sounds than those who were not exposed to nature based sounds at α level of 0.05.

Design:

It was a randomized controlled trial pretest-posttest control group design (single blinding). The intervention was given for over a period of 60 minutes and post test was done after every 15 minutes from the baseline and 30 minutes after finishing the intervention.

Randomization and blinding:

Patients were allocated to the NBS and without NBS group along with routine care using a computer-generated randomization list. The allocation was sealed in thick, opaque envelopes before data collection. After participants completed the baseline data evaluation, the sealed envelopes were opened sequentially. The sealed envelopes prepared and opened by nurse on duty daily and she put the headphones on selected patients. The researcher was blinded to random assignment throughout the study period.

Sample Size estimation:

As per the pilot study done in 10 patients, mean anxiety score (1.2±0.44) in experimental group and 1.53±0.67 in control group, assuming 5% level of significance and 80% power, estimated sample size was 120 (60 in each group of experimental and control).

Inclusion criteria:

The patients aged between 18 and 65 years under mechanical ventilation support on pressure support ventilation mode and SIMV for 48 hours in an ICU, having Glasgow Coma score of 9 or above. Patients who were able to hear and see, non-drug-addicted, not taking any neuromuscular blocker agent and antihypertensive drug, not currently using NBS intervention and without any psychiatric or neurological illnesses.

Exclusion criteria:

Patients extubated from mechanical ventilation, having a skull injury that restricted the use of headphones, physical restrained, who need emergency dose- stat sedative and not willing to participate in the study.

Tools and techniques:

Anxiety was assessed by Faces anxiety scale (FAS)¹⁷. This scale was chosen because it has been demonstrated to be easier for ICU patients to respond to in comparison to other anxiety scales¹⁸. It has an established criterion validity of 0.70 at p<.0005. Agitation was assessed by The Richmond Agitation Sedation Scale (RASS). Its inter-rater reliability was quite high (r= 0.922–0.983).

Intervention (nature-based sounds):

The preliminary authors were contacted for providing different sounds and CD was further prepared by combining different sounds. The CD was given to different experts in the field of anaesthesia, ICU, Nursing for the quality, pitch, frequency and rhythm of the sounds. The sounds included birds ‘chirping, soothing rain sounds, river streams, waterfall sounds and sea waves sound. The subjects in the experimental group wore the foam-lined headphones. The volume of the media player was adjusted according to the subjects’ comfort by responding to their facial expression and holding up fingers responsive to confirmationby nurse on duty. The subjects were asked to remain comfortable as they feel by closing or opening their eyes and follow the sounds during the intervention. The subjects in control group also wore the same foam-lined headphones and without any nature based sounds and remained quiet for the same time duration. Post-test measures were assessed after the finishing of the experiment according to the study protocol

Procedure for Data Collection:

The institute ethics committee of the AIIMS hospital granted the approval of the study). All participants were explained about the voluntary participation and withdrawal from the study at any given point of time and their written informed consent was taken prior to participating in the study. The informed consent paper was read by the researcher for all the patients. The patient’s anxiety and agitation were assessed using standardized tools before intervention of the subjects in both groups. NBS was played between 5 to 6 pm to accommodate nursing activities and the unit’s routine. The duration of nature-based sounds was 60 minutes for each patient. The anxiety and agitation were assessed every 15 min for both the groups and 30 minutes after the intervention without headphones. The data was collected from October 2016 to August 2017. The approximate time taken for each subject was 2 hours for one setting of NBS and other group too. Consort diagram is given in fig. 1

Fig. 1: consort diagram

RESULT:

SPSS version 16.0 was used to analyze the data. The data collected was coded, entered into a Microsoft excel sheet and all entries were checked for any errors. Chi-square tests were used to detect any significant difference between the groups’ demographic and clinical data. Mann Whitney U-test was used to detect any significant difference on anxiety and agitation between the two groups

Both the groups were found homogeneous in terms of sample demographic and clinical characteristics, has been shown in table 1 and table 2.

Table 1: Distribution of Demographic variables of subjects in experimental and control groups N=120

Demographic Variables	Experimental group f (%), n=60	Control group f (%) n=60	p value
Gender: Males	35 (58)	37 (62)	0.70 ^χ²
Females	25 (42)	23 (38)	0.70 ^χ²
Age (years): Means (range)	47.07±10.66 (25-65)	46.90±10.95 (18-62)	0.93^t
Residence: Urban	41 (68)	43 (72)	0.69^χ²
Rural	19 (32)	17 (28)	0.69^χ²
Education: Illiterate	18 (30)	24 (40)	0.42^χ²
Primary	4 (7)	8 (13)
Senior secondary	9 (15)	6 (10)
Undergraduate	8 (13)	7 (12)
Postgraduate	21 (35)	15 (25)
Occupation: Labourer	3 (5)	11 (18)	0.15^χ²
Skilled worker	11 (18)	13 (22)
Unskilled worker	5 (8)	2 (3)
Professional	17 (29)	15 (25)
Others	24 (40)	19 (32)
Marital status: Married	53 (88)	54 (90)	0.76^χ²
Unmarried	7 (12)	6 (10)	0.76^χ²
Type of family: Nuclear	18 (30)	20 (33)	0.69^χ²
Joint	42 (70)	40 (67)	0.69^χ²
Smoking status: Smoker	22 (37)	34 (57)	0.02*^χ²
Non-smoker	38 (63)	26 (43)	0.02*^χ²

chi-square (χ²), independent ‘t’ test * p value<0.05

Table no 2: Distribution of clinical variables of subjects in experimental and control groups N=120

Clinical variables	Experimental group f (%), n=60	Control group f (%), n=60	p value
Medical diagnosis			0.69
Pleural effusion	8 (13)	9 (15)
Respiratory arrest	7(12)	6 (10)
Interstitial lung disease (ILD)	6 (10)	10 (17)
Chronic obstructive pulmonary disease (COPD)	21 (35)	15 (25)
Obesity with obstructive sleep apnea (OSA)	18(30)	20 (33)
Mode of ventilation
volume controlled ventilation (VCV)	24 (40)	23 (38)	0.92
Synchronous intermittent mandatory ventilation (SIMV)	11 (18)	14 (23)
Pressure support ventilation (PSV)	17 (28)	16 (27)
Assisted controlled ventilation (A/C)	8 (13)	7 (12)
Length of stay in ICU (days)
0-4	16 (27)	25 (42)	0.18
5-8	34 (57)	25 (42)
>8	10 (16)	10 (16)
Length of stay in ICU before NBS
0-4	20 (33)	27 (45)	0.42
5-8	32 (53)	26 (43)
Above 8	8 (13)	7 (12)
No of days on mechanical ventilation
0-4	21 (35)	27 (45)	0.45
5-8	31 (52)	28 (47)
Above 8	8 (13)	5 (8)
GCS score
9	32 (53)	36 (60)	0.46
10	28 (47)	24 (40)	0.46

chi-square (χ²), p value>0.05

Table 3: Frequency distribution of subjects in experimental and control groups according to anxiety scores before, during and after nature-based sounds’ intervention. N=120

Time	experimental Group (n=60): Anxiety scores			control Group 2 (n=60): Anxiety scores
Time	Not anxious	A little bit anxious	Fairly anxious	Not anxious	A little bit anxious	Fairly anxious
Baseline	4 (6.6)	43 (71.6)	13(21.6)	5 (8.3)	48(80)	7 (11.6)
15 minutes	32 (53.3)	21 (35)	7 (11.6)	14 (23.3)	38(63.3)	8 (13.3)
30 minutes	44(73.3)	15 (25)	1 (1.6)	16 (26.6)	38(63.3)	6 (10)
45 minutes	55 (91.6)	4 (6.6)	1 (1.6)	17 (28.3)	39 (65)	4(6.6)
60 minutes	58 (96.6)	2 (3.3)	0	17(28.3)	38(63.3)	5(8.3)
30 min after NBS	59 (98.3)	1 (1.6)	0	27 (45)	29 (48.3)	4(6.6)

Table 4: comparison of anxiety scores in experimental and control group.N=120

Time	Group	Median	Mean difference	Mann Whitney U value	p value
Baseline	Experimental (n=60) Control (n=60)	2 2	0.03	1722.50.00	0.55
15 min	Experimental (n=60) Control (n=60)	1 2	0.55	936.00	<0.001*
30 minutes	Experimental (n=60) Control (n=60)	1 2	0.79	542.50	<0.001*
45 minutes	Experimental (n=60) Control (n=60)	1 2	0.95	253.50	<0.001*
60 minutes	Experimental (n=60) Control (n=60)	1 2	0.92	328.50	<0.001*
30 min after NBS	Experimental (n=60) Control (n=60)	1 2	0.68	798.00	<0.001*

0.05 level of significance *-Significant

Effect of NBS on agitation

Table 5: Frequency distribution of samples in experimental and control group according to RAAS scores before, during and after nature-based sounds’ intervention. N=120

Time	Experimental Group (n=60) Agitation frequency (%)			control group (n=60) Agitation frequency (%)
Time	Restless	Agitated	Very agitated	Restless	Agitated	Very agitated
Baseline	4 (6.6)	34 (56.6)	22 (36.6)	0	47 (78.3)	13 (21.6)
15 min	21(35)	31 (51.6)	8(13.3)	6 (10)	40 (66.6)	14 (25)
30 minutes	40 (66.6)	18 (30)	2(3.3)	9(15)	38 (63.3)	13 (21.6)
45 minutes	46 (76.6)	12 (20)	2(3.3)	10 (16.6)	35 (58.3)	15 (25)
60 minutes	49 (81.6)	9 (15)	2(3.3)	10 (16.6)	35 (58.3)	15 (25)
30 min after NBS	47 (78.3)	12 (20)	1(1.6)	21 (35)	26 (43.3)	13(21.6)

Table 6: comparison of agitation scores in experimental and control group. N=120

Time	Group	Median	Mean difference	Mann Whitney U value	p value
Baseline	Experimental (n=60) Control (n=60)	2 2	0.07	1652.00	0.25
15 min	Experimental (n=60) Control (n=60)	2 2	0.41	1199.00	0.003*
30 minutes	Experimental (n=60) Control (n=60)	1 2	0.77	680.50	0.001*
45 minutes	Experimental (n=60) Control (n=60)	1 2	0.86	578.00	0.001*
60 minutes	Experimental (n=60) Control (n=60)	1 2	0.91	51.50	0.001*
30 min after NBS	Experimental (n=60) Control (n=60)	1 2	0.44	1148.00	0.001*

0.05 level of significance *- Significant

Table 7: Association of agitation, anxiety and physiological stress response scores with selected demographic variables N=120

		Experimental group (n=60)			Control group (n=60)
Research variables	Demographics	χ²	df	p value	χ²	Df	p value
Agitation	Age	6.91	6	0.32	3.85	3	0.27
	Gender	0.45	2	0.79	0.73	1	0.53
	Smoking status	2.80	2	0.24	1.62	1	0.23
	Length of ICU stay	4.09	4	0.39	1.30	2	0.52
	Ventilator mode	9.26	6	0.15	*10.77*	3	0.01*
	GCS	4.05	2	0.13	7.47	1	0.05
Anxiety	Age	2.65	3	0.44	2.43	3	0.48
	Gender	1.01	1	0.355	0.06	1	1.00
	Smoking status	*6.00*	1	0.02*	0.61	1	0.45
	Length of ICU stay	0.97	2	0.61	3.91	2	0.14
	Ventilator mode	1.26	3	0.73	*11.39*	3	0.01*
	GCS	0.44	1	0.54	*8.95*	3	0.03*

Majority (56.6.6%) of the subjects in the experimental group and 78.3% of the subjects in control group were agitated at baseline and most of them were found to be not in the restless category than agitated category after NBS were played for them as compared to control group in which most of the subjects were either agitated or very agitated as shown in (table 5). After applying Mann Whitney U test (as shown in table 6), for significance and inference, the subjects in both the groups were found comparable (p=0.25). There was a significant reduction in the agitation level from baseline among the subjects of experimental groups as compared to control group. (p =0.003 at 15 minutes, p=0.001 at 30 minutes, p=0.001 at 45 minutes, p=0.001 at 60 minutes and p=0.001 after 30 minutes of removal of Nature based sounds).

There was no significant association of agitation and anxiety with selected demographic and clinical variables such as age, gender and smoking status as calculated values of χ2 was less than the table value at 0.05 level of significance (χ2= 3.841) as shown in table no 7.

DISCUSSION:

The present study aimed to investigate the effects of nature-based sounds on anxiety and agitation in patients on mechanical ventilator support in respiratory ICU. We hypothesized that the subjects who listened to nature-based sounds would show significant reduction in anxiety and agitation than the subjects not exposed to nature-based sounds.

Natured based sounds as an inexpensive and non-invasive, non-pharmacological intervention has been used in various studies in recent years. The study findings indicated that at six different time points nature-based sounds significantly reduced anxiety when compared to non-nature-based sounds arm. Similar findings were reported by Chiang^15,18,19,20 that both nature sounds and music caused relaxation and distraction and reduced pain and anxiety. In support of the present study, Hansen-Ketchum and Halpenny²¹ reported that the nature-based sounds create conditions that promote human and environmental health by reducing anxiety and facilitating psychological and physical activity. Tan et al²² also confirmed with the present study findings that sound therapy can reduce anxiety, pain, muscle tension, and compression during daily care.

The patients in control group in the present study with headphones on but without any nature-based sounds didn’t show any significant reduction in anxiety and agitation. This was similar to a study by Tsivian et al²³ in which silence produced using headphones had no significant effects on pain and anxiety. Mehran Farzaneh et al²⁴ also reported the same findings indicating that headphones alone as a mediating factor could not lead to a reduction in the mothers’ pain. The study by Mirbagher Ajorpaz and Aghajani²⁵concluded that headphones can block environmental sounds.

LIMITATIONS:

The present study had few limitations. Firstly, there were five different types of nature-based sounds and the subjects might not have their favorite sounds as per their choice which might have reduced the effect of the intervention. The sounds could have been given by asking individual subjects’ preference. However, since the results showed positive effects; we may conclude that that the limited choices over sounds selection did not considerably affect our results. Secondly, since the patients were chosen from one respiratory ICU of the hospital, their demographic and clinical characteristics might be similar to some extent but the findings can’t be generalized to broader population. Patients in the control groups who wore headphones without any natural based sounds might have experienced anxiety which was not assessed.

IMPLICATIONS:

The findings of this study imply that nature-based sounds can significantly improve psychological stress responses in patients on mechanical ventilator support in ICU. Nursing managers and hospital authorities need to provide adequate training, equipment, and facilities to nurses to facilitate their use of such strategies.

RECOMMENDATION:

Further studies might be undertaken to ascertain whether the effect of particular sound they liked were more affirmative than the sounds they didn’t like if used in separate ways such as individually, combination of two sounds and all the sounds in one group. Further studies comparing the effects of music interventions with different frequencies (e.g., once or twice per day) are warranted.

CONCLUSION:

The findings of the present study and those of previous research indicate that nurses in the clinical setting may use nature-based sounds as a healing ambience to help reduce ICU patients’ anxiety and agitation levels and to promote health and well-being of the patients. However, as the duration of the effect of intervention is indistinct, nurses need to monitor patients’ psychological stress after providing the nature-based sounds’ intervention. In addition, nurses must be sensitive enough to understand that individual patients may have different responses to nature-based sounds so that they may consider providing the nature-based sounds according to their preferences.

ACKNOWLEDGEMENT:

The researchers would like to thank the patients for their participation in this study.

CONFLICTS OF INTEREST:

None of the authors have any conflicts of interests with regards to this research.

ETHICAL APPROVAL:

Ref. No. IESC/T-393/28.11.14 by institute ethics committee, New Delhi.

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Received on 10.07.2019 Modified on 31.07.2019

Int. J. of Advances in Nur. Management. 2019; 7(3): 169-175.

DOI: 10.5958/2454-2652.2019.00041.6