Hwang 1998.

Methods	RCT, parallel design, 2‐arm, single‐centre study Aim of the study: to investigate the effects of an audio‐recorded message from the attending cardiac surgeon that provides information and emotional support on the physiological and psychological reactions of heart surgery patients during the early recovery phase in the ICU
Participants	Total number of randomised participants: 60 Inclusion criteria: patients > 16 years of age, alert and oriented, with no visual or auditory defects, and no psychiatric illness or cognitive impairment Exclusion criteria: not reported Participant baseline characteristics Patient: Age not reported by group. Overall age, mean (SD): 52.7 (± 15.5) years Intervention group Gender, M/F: 18/12 BMI: not reported Illness severity: not reported Mechanically ventilated: assumed patient participants were ventilated because of description of information included in recorded message Primary diagnoses: heart disease Additional information (e.g. socio‐economic characteristics, nationality, primary language): participant education levels: < middle school (N = 13), > middle school (N = 17); occupation: professional (N = 13), non‐professional (N = 17); social class I‐III (N = 7), social class IV (N = 8), social class V (N = 15) Health literacy status (number correct on REALM‐SF): not reported Control group Gender, M/F: 16/14 BMI: not reported Illness severity: not reported Mechanically ventilated: assumed patient participants were ventilated because of description of information included in recorded message Primary diagnoses: heart disease Additional information (e.g. socio‐economic characteristics, nationality, primary language): participant education levels: < middle school (N = 16), > middle school (N = 14); occupation: professional (N = 6), non‐professional (N = 24); social class I‐III (N = 4), social class IV (N = 3), social class V (N = 23) Health literacy status (number correct on REALM‐SF): not reported Country: Taiwan Setting: ICU in National Taiwan University Hospital (surgical)
Interventions	Recipient of the information: patient participant Intervention group Patient participants: N = 30; no losses Details: patient participant given standardised audio message recorded by physician. Message played back to patient participant during ICU recovery. Duration of message was 6 to 10 minutes and was given 5 to 10 hours after heart surgery. Information included reassurance, general ICU information, rehabilitation information, and treatment plan. Intervention given once. Control group Patient participants: N = 30; no losses Details: patient participants given no information. Patient participants given earphones to block out other noises.
Outcomes	Outcomes reported in the review: Anxiety and depression of patient participant, postoperatively in cardiosurgical unit (using BSRS; each symptom is scored from 1 to 7 with 18 to 24 possible symptoms; lower scores indicate less depression) Other outcomes reported in the study: Pain, tension, psychological reactions, and hostility of patient participant
Notes	Funding/declarations of interest: not reported Study dates: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomly assigned, but no additional details
Allocation concealment (selection bias)	Unclear risk	No evidence of allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	High risk	It was not possible to blind participants. It may have been possible to blind personnel, but insufficient details were provided.
Blinding of assessment for patient‐related outcomes (detection bias)	Unclear risk	Assessment of anxiety and depression with BSRS. Study authors do not report whether independent investigators were involved in these assessments. It is not clear whether awareness of group allocation would have influenced patient‐reported outcome data.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	No clinical trial registration or pre‐published protocol. Not feasible to judge selective outcome reporting
Other bias	Low risk	No other sources of bias identified.