Richardson 2003.

Methods	Design: 2‐arm, parallel group design RCT Setting: 3 intensive care units, single‐bed rooms in 2 teaching hospitals, USA
Participants	Inclusion criteria "Adults (18 years or older) admitted to ICU with nurse‐patient acuity ratio of 1:1 or 1:2" Exclusion criteria "Unstable patients with an acuity ratio of 2:1 or more (such as patients on an intraaortic balloon pump or a left ventricular assist device) Patients with a history of Alzheimer's disease, dementia, psychoses, central neurological impairment (cerebrovascular accident, head injury, cranial surgery, coma), severe bradycardia, or severe hypotension Non‐English‐speaking patients" Total numbers randomized: 36 Total numbers analysed: 29 (17 in the control group and 12 in the experimental group) Sex: 17 men, 19 women Mean age: 58.4 years
Interventions	Experimental group: a combination of relaxation and imagery; the participant received the intervention for 2 evenings, between the hours of 5 p.m. and 7 p.m.. The investigator designed the intervention to be from 13 to 18 minutes in length, and the intervention was delivered in person Control group: usual care without relaxation and imagery Study duration: 2 days
Outcomes	Primary outcome Subjective sleep scores: used the Verran/Snyder‐Halpern (VSH) Sleep Scale, an 8‐item visual analogue instrument using a 100 mm response line, to measure the sleep quality; 3 items were added to the tool for this study, and 1 item was revised, resulting in an 11‐item visual analogue instrument. These 11 items were numbers of awakenings, hours awake, hours of sleep, concern with interruptions, time to first sleep, concern with time to first sleep, depth of sleep, sufficiency of sleep, refreshment upon awakening, number of naps taken during the previous day, and good or bad night. Higher sleep scores indicated a perception of improved sleep
Notes	There were no significant differences between groups for any demographic variable There was no pattern of administration of medications that could have affected sleep over time for any participant The paper did not report the results of sleep scores on day 1, day 2, and day 3 The mean sleep scores of the baseline night were as follows: control group was 57.85 ± 44.1, intervention group was 82 ± 44.6, showing a significant difference between them We attempted to contact author Dr S Richardson via email; however, we received no response
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization was generated using a coin toss
Allocation concealment (selection bias)	Unclear risk	Allocation concealment was not described
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "The investigator was responsible for recruitment and was the individual who presented the tool to the subject on day 1. The research assistant, without knowing group membership of the subject, presented the tool to the subject on days 2 and 3" Comment: however, self‐report measures were used for subjective sleep data, and participants were not blinded
Blinding of participants and personnel (performance bias) All outcomes	High risk	It was not possible to blind participants and personnel to the intervention
Incomplete outcome data (attrition bias) All outcomes	High risk	The refusal rate for participation was 16% (n = 6); 36 were randomized; 29 were analysed 19.4% of participants dropped out
Selective reporting (reporting bias)	High risk	The results of sleep scores on day 1, day 2, and day 3 in both groups were not reported
Other bias	High risk	The mean sleep scores of the first night (namely baseline) were significantly different between the 2 groups