Ozgundondu 2019.

Study characteristics
Methods	Study design: randomised controlled trial Study grouping: parallel group
Participants	Baseline characteristics Progressive muscle relaxation combined with music Age in years (mean ± SD): 24.61 ± 2.61 Sex (N (% female)): 28 (100%) Sample size: 28 Years of experience (category (n (%))): 6 to 23 months (16 (57.1%)) ‐ 24 months+ (12 (42.9 %)) Control (no intervention) Age in years (mean ± SD): 27.75 ± 4.75 Sex (N (% female)): 28 (100%) Sample size: 28 Years of experience (category (n (%))): 6 to 23 months (10 (35.7%)) ‐ 24 months+ (18 (64.3 %)) Overall Age in years (mean ± SD): NR Sex (N (% female)): 56 (100%) Sample size: 56 Years of experience (category (n (%))): NR Included criteria: the eligible nurses included those who (a) were 18 years old, (b) had an experience of at least three months in ICUs, and (c) had no documented history of chronic obstructive pulmonary disease, heart failure and asthma. Excluded criteria: the exclusion criteria were as follows: (a) history of severe psychiatric disorder, (b) ICU experience of less than three months, and (c) not currently using any complementary therapy modalities such as acupuncture, massage therapy, relaxation techniques, and yoga that can be influential on perceived stress and fatigue or coping styles. Pretreatment: the study groups were homogeneous in terms of age, gender, marital status, educational level, income status, living with either their family or friends, comorbid conditions, experience in ICU, working hours per week and satisfaction levels with ICUs (P > 0.05). Compliance rate: 90% Response rate: 89% Type of healthcare worker: exclusively nurses
Interventions	Intervention characteristics Progressive muscle relaxation combined with music Type of the intervention: Intervention type 2 ‐ to focus one’s attention away from the experience of stress Description of the intervention: The nurses who were grouped in the intervention group were provided with a booklet containing the definition, purpose, benefits, and application techniques of PMR and music therapy. The participants were first taught the description, using fields and effects on the body of the PMR plus music therapy. Subsequently, step‐by‐step instructions on PMR were provided by the PI. After the demonstration by PI, all the PMR steps were practised by the participants under the supervision of PI within the duration of 20 minutes, following which, PMR booklets prepared by the researchers were delivered to the nurses in the training session itself. The number of sessions: 8 Duration of each session on average: 20 minutes Duration of the entire intervention: 8 weeks Duration of the entire intervention short vs long: short Intervention deliverer: The principal investigator (PI), who had work experience in relaxation and music therapy Intervention form: group sessions, which composed of 10–15 participants Control (no intervention) Type of the intervention: NA Description of the intervention: a single‐time face‐to‐face attention‐matched educational session, on the first day of the study and no additional intervention was conducted for this group during the whole study period. Was performed with a booklet containing the causes, negative effects of stress and fatigue on the body, and techniques for coping with stress The number of sessions: 1 Duration of each session on average: 20 minutes Duration of the entire intervention: NA Duration of the entire intervention short vs long: NA Intervention deliverer: NA Intervention form: face‐to‐face; 10–15 participants; a silent room located in the hospital.
Outcomes	Perceived Stress Scale (PSS) Outcome type: ContinuousOutcome
Identification	Sponsorship source: The author(s) received no financial support for the research, authorship, and/or publication of this article Country: Turkey Setting: University of Health Sciences, Ankara Gulhane Training and Research Hospital Comments: NR Authors name: Zehra Gok Metin Institution: Hacettepe University Email: zehragok85@hotmail.com Address: Hacettepe University, Faculty of Nursing, 06000 Sihhiye, Ankara, Turkey. Time period: were recruited from 1 July 2018 to 15 January 2019.
Notes	We kindly received the mean and SD from the author.  PSS included in analysis 2.1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "were assigned randomly into two groups (Group A: 31; Group B: 32) through lottery method (A: Control; B: Intervention)"
Allocation concealment (selection bias)	Low risk	Quote: "by the second author of the present report who was not involved in the intervention procedures, and the PI informed the nurses about the randomisation results."
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "All the sessions comprising PMR combined with music were also conducted by the PI who was not blinded to the study groups due to the nature of PMR. ,"
Blinding of outcome assessment (detection bias) All outcomes	High risk	Participants were not blinded whereas outcomes are self‐reported.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up
Selective reporting (reporting bias)	Unclear risk	No trial registration, nor did we find one online.
Other bias	Low risk	No indication of other bias.