Table 1.

Summary of reviewed studies.

Author/Year	Design	Purpose	Setting/Subjects	Variables Measured	Findings
Almerud&Peters son, (2003)35	Mixed Methods Intervention: Classical music for 30 minutes in conjunction with night sleep Control: Rest under similar circumstances as the intervention group	Purpose: to discover whether music therapy had a measurable relaxing effect on patients who were temporarily on a respirator in an ICU and after completion of respirator treatment investigate those patients’ experiences of music therapy	16 bed ICU in Sweden 20 subjects for quantitative data 6 subjects for qualitative interviews	Quantitative: Vital signs every 5 minutes during intervention Qualitative: Interview questions about memories of MV after ventilation terminated	-Statistically significant drop in BPb during intervention -Non-statistically significant drop in HR during intervention -Subjects had poor memory of time on the ventilator. No subjects recalled listening to music while ventilated -Three themes identified: 1) Anxiety and discomfort, 2) Illusory Feelings, 3) Close Relationship
Beaulieu-Boire, et al. (2013)34	Randomized Crossover (3 days with a washout on day 2) Intervention: Slow tempo music for 1 hour, 2 times per day Control: Rest with headphones with no music	Purpose: to evaluate the impact of slow tempo music listening periods in mechanically ventilated intensive care unit patients	16 bed ICU in a tertiary hospital in Canada 49 subjects	Vital signs before and after intervention Sedative drug consumption Blood tests for biomarkers before and after intervention	-No significant change in vital signs observed -Trend towards decrease in Fentanyl in intervention group -Blood cortisol and prolactin decreased after intervention
Chlan (1995)33	Two group experimental design Intervention: Classical music listening for 30 minutes during late afternoon/evening Control: Rest with headphones with no music	Purpose: to examine selected psychophysiological responses of mechanically ventilated patients to music	Single ICU at a tertiary care center in the US Intervention group: 11 subjects Control group: 9 subjects	Vital signs before, at 5 minute intervals during intervention, and 5 minutes after intervention Anxiety measured using Profile of Mood States (POMS) 30 item short form	-Statistically significant decreases in HR, BP, and RR observed in the intervention group -Statistically significant difference found in POMS scores between groups
Chlan (1998)32	Two group experimental design Intervention: Non lyrical, relaxing music with 60–80 bpm for 30 minutes Control: Rest with no headphones for 30 minutes	Purpose: to test the effects of music therapy on relaxation and anxiety reduction for patients receiving ventilator assistance	4 urban ICUs in the US Intervention group: 27 subjects Control group: 27 subjects for control	Vital signs at baseline, every 5 minutes, and at 30 minutes Anxiety measured by pretest/posttest 6 item version of Spielberger State Anxiety Inventory	-Statistically significant difference between pretest and posttest anxiety scores for the intervention group -HR and RR decreased over time for the intervention group
Chlan et al. (2007)38	Pilot Study: two group experimental design Patient selected music listening for 60 minutes Control: Rest with no headphones for 60 minutes	Purpose: to explore the influence of music on serum biomarkers of the stress response in patients receiving ventilator support	11 bed ICU in a University medical center in the US Intervention group: 5 subjects Control group: 5 subjects	Levels of corticotropin, epinephrine and norephinephrine measured 4 times during each 60 minute session HR: measured 4 times during each 60 minute music listening session	-No clear pattern of SNS activity was apparent from the levels of biomarkers -Levels of biomarkers did not differ significantly between intervention and control group -Levels of corticotrophin and cortisol decreased over time for the music group, but this decrease was not statistically significant
Chlan et al. (2012)41	Three group randomized clinical trial Patient Directed Music (PDM): self-initiated, PDM with preferred selection tailored by a music therapist Headphones (HP): self initiated application of noise canceling headphones Control: U0sual care (UC)	Purpose: to explore the influences of music on stress in a sample of patients of the duration of ventilator support	12 ICUs at 5 urban hospitals in the US PDM group: 19 subjects HP group: 27 subjects UC group: 19 subjects	24 hour Urinary free cortisol (UFC) collected from 0700 hours to 0700 hours each day the subject was enrolled in the study	-No significant differences in UFC among groups over the course of ventilator support -Extremely high variability in study entry levels of UFC noted which could have impacted results
Chlan et al. (2001)37	Descriptive pilot study	Purpose: to test feasibility of patient-initiated music intervention protocol over a 3 day trial and to discern the associated barriers to adherence by study participants and nursing staff	1 ICU at a tertiary care center in the US 5 subjects	Vital signs measured at baseline and after completion of the intervention Anxiety measured by a visual analogue scale, given before and after each intervention session	-Patient initiated music is a feasible intervention protocol -Subjects were able to independently request music -Nurses were cooperative in offering the intervention
Chlan et al. (2013)17	Three group randomized clinical trial Patient Directed Music (PDM): self-initiated, PDM with preferred selection tailored by a music therapist Headphones (HP): self-initiated application of noise canceling headphones Control: Usual Care (UC)	Purpose: to test whether listening to self-initiated PDM can reduce anxiety and sedative exposure during ventilator support in critically ill patients	12 ICUS at 5 urban hospitals in the US PDM group: 126 subjects HP group: 122 subjects UC group: 125 subjects	Daily anxiety measured by visual analogue scale Sedative exposure measured by sedative drug intensity score	-PDM subjects had significantly lower anxiety scores than subjects in the UC group -By the 5th study day, anxiety was reduced by 36.5% in PDM patients -PDM significantly reduced measures of sedative exposure -By the 5th study day, PDM subjects received 2 fewer sedative doses than subjects in the UC group
Conrad et al. (2007)40	Two group randomized clinical trial Intervention: slow movements of Mozart’s piano sonatas for 1 hour Control: Rest for 1 hour with headphones with no music	Purpose: to identify mechanisms of music-induced relaxation using a special selection of slow movements of Mozart’s piano sonatas	1 ICU 10 subjects	Vital signs, continuously during intervention Brain electrical activity, continuously during intervention Serum levels of stress hormones and cytokines before and after intervention Requirements for sedative drugs Level of sedation before and after music intervention	-The intervention significantly reduce the amount of sedative drugs needed to achieve a comparable degree of sedation -Subjects that received music had increased levels of growth hormone and decreased levels of interleukin-6 and epinephrine -The reduction in stress hormones in the subjects that received music was associated with a significantly lower blood pressure and heart rate
Dijkstra, et al. (2010)21	Two group randomized clinical trial Intervention: Listened to music 3 times for 30 minutes over 2 days Control: had 3 rest periods for 30 minutes of 2 days	Purpose: to determine the effects of music on physiological responses and sedation scores in sedated, mechanically ventilated patients	3 ICUs in a university hospital in the Netherlands Intervention group: 10 subjects Control group: 10 subjects	Vitals signs at baseline, after 5, 10, 20, 30, 60 minutes Sedation scores measured by the Ramsay Sedation Scale measured at baseline and after music or rest	-Subjects in the intervention group had higher sedation scores, indicating music leads to a deeper level of sedation -No significant decreases in physiological parameters were observed
Han et al. (2010)28	Three group randomized clinical trial Listening to relaxing music for a single 30 minute session Headphones with no music for a single 30 minute session Control with quiet rest for a single 30 minute session	Purpose: to examine the effects of music intervention on the physiological stress response and the anxiety level among mechanically ventilated patients in the intensive care unit	A single ICU at a large teaching hospital in China Music listening group: 44 subjects Headphones group: 44 subjects Control group: 49 subjects	Vital signs, baseline, every 5 minutes during intervention and at 5 minutes after intervention Anxiety measured by the Spielberger State-Trait Anxiety Scale, measured before and after 30 minute session or all groups	-Significant differences among groups for HR, BP, RR, and anxiety -Significant reduction in physiological stress response over time in music listening group -Significant increase in physiological stress response over time in control group -Significant reduction in anxiety score for the music group and headphone group
Hunter et al. (2010)4	Feasibility study with historical controls Intervention: 45–60 minute MT sessions offered 3 times/week during weaning trials; time of session determined by where patient was in weaning process	Purpose: to determine the feasibility of incorporating music therapy in to the weaning process and to evaluate the efficacy of the intervention based on levels of anxiety, days to wean and patient/nurse satisfaction	A single pulmonary step down unit of a large tertiary teaching hospital in the US 61 subjects	Anxiety measured by a patient survey and a staff survey Vital signs before and after each music therapy session Days to Wean (DTW) Satisfaction measured by a patient survey and a staff survey	-Patient and nurse satisfaction with the intervention were both high -Significant difference in HR and RR found from beginning to the end of the music therapy session suggesting a more relaxed state had been achieved -Staff assessment of anxiety demonstrated patient appeared to be less anxious after intervention
Korhan et al. (2011)23	Case control experimental study Intervention: Classical music listening for 60 minutes Control: Usual ICU care	Purpose: to investigate if relaxing music is an effective method of reducing the physiological signs of anxiety in patients receiving mechanical ventilator support	A single ICU in a teaching hospital in Turkey 30 subjects for the intervention 30 subjects for the control	Vital Signsmeasured immediately before the intervention, at the 30th, 60th, and 90th minutes of the intervention, and 30 minutes after the intervention	-Subjects in the music group had significant lower mean RR and BP than the control group -The decrease in RR and BP improved progressively in the 30th, 60th, and 90th minutes of the intervention suggesting a cumulative dose effect
Lee et al. (2005)24	Two group randomized clinical trial Intervention: 30 minute relaxing music listening Control: 30 rest period with headphones with no music	Purpose: to investigate effects of music on the anxiety of patients on mechanical ventilators as assessed by objective parameters and a subjective validated anxiety scale	A single ICU in Hong Kong Intervention group: 32 subjects Control group: 32 subjects	Vital signs measured before and after the intervention Anxiety measured by the Chinese version of the Spielberger State Trait Anxiety Inventory Scale measured before and after the intervention Resting Behavior Observation checklist Patient Satisfaction measured before and after the intervention	-Significant decreases in HR, RR, systolic BP and diastolic BP were noted after the music intervention in the music group -An increased in observed resting behaviors was observed in the intervention group
Saadatmand et al. (2013)31	Two group randomized clinical trial Intervention: 30–90 minutes of listening to nature based sounds Control: 30 minute rest period with headphones with no music	Purpose: to identify the effect of the nature-based sounds’ intervention on agitation, anxiety level, and physiological stress responses in patients under mechanical ventilation support	A single ICU in a teaching hospital in Iran Intervention group: 30 subjects Control group: 30 subjects	Vital signsmeasured before the procedure, at the 30th, 60th, and 90th minutes of the procedure and 30 minutes after procedure Anxiety measured by the FACES anxiety scale 30 minutes after the intervention Agitation measured by the Richmond Agitation Scale during the intervention	-The intervention group had significantly lower systolic BP, diastolic BP, anxiety and agitation levels than the control group -The reductions observed were progressive over time, indicating a cumulative dose effect
Stubbs (2005)39	Qualitative Study Intervention: 30 minutes of relaxing music listening on 2 prescribed occasions	Purpose: to gain insight into patients’ and nurses’ perception of the benefit of music therapy during critical illness and to add to the body of knowledge in nursing around the use of therapies complementary to medicine	A single ICU in a community hospital in the US 5 patients 4 nurses	Unstructured interviews after ICU discharge but before leaving the hospital. Results were analyzed according to Burnard’s framework	-When interviewed, no patients remembered listening to music. Nursing staff made timetables of music interventions which was successful in jogging patients’ memories -Patients’ notable comments concerned 1) imagery, 2) being somewhere else, 3) pain perception altered by music, 4) sleep relaxation, 5) music dreams -None of the nurses interviewed felt there were any disadvantages and found the results to be positive
Twiss et al. (2006)36	Two group randomized clinical trial Intervention: listened to music continuously throughout surgery and while in ICU Control: received usual postoperative care	Purpose: to determine the effect of music listening on postoperative anxiety and intubation time in patients undergoing cardiovascular surgery	A single ICU in the US Intervention group: 28 subjects Control Group: 32 subjects	Anxiety measured by the Spielberger State Trait Anxiety inventory administered the night before surgery and the 3rd postoperative day Intubation time – measured by the time patient left the OR until they were extubated	-Subjects in the music group had significantly lower anxiety scores -Subjects in the music group had fewer minutes of postoperative intubation after cardiovascular surgery
Wong et al. (2001)22	Crossover design with random assignment Randomized to get 30 minutes of music therapy then 30 minutes of uninterrupted rest or vice versa Music: relaxing music via headphones Control: uninterrupted rest	Purpose: to assess the effectiveness of music therapy in decreasing anxiety in ventilator dependent patients	A single ICU in Hong Kong 20 subjects	Vital signs measured before intervention and at 5 minute intervals throughout intervention Anxiety measured by the Chinese version of the Spielberger State Trait Anxiety Inventory measured before intervention and immediately after intervention	-Music listening was more effective in decreasing state anxiety than uninterrupted rest period -Significant difference of BP and RR were observed at the end of the intervention between the two conditions, with music being superior to the rest period

^bHR-heart rate, BP – blood pressure, RR – respiratory rate