Effects of Nature Sounds on Sleep Quality among Patients Hospitalized in Coronary Care Units: A Randomized Controlled Clinical Trial

Background: Sleep disorders are a source of stress for patients hospitalizedin coronary care units (CCUs). Objective: The aim of this study was toinvestigate the effects of nature sounds on sleep quality among patients inCCUs. Methods: This randomized controlled trial was conducted on 93 patientshospitalized in the CCUs of three teaching hospitals in Tehran, Iran. Patientswere randomly allocated into three groups, namely, nature sounds, silence, andcontrol groups. Patients in the nature sounds group listened to nature sounds for30 min in two consecutive nights while their counterparts in the silence grouponly wore mute headphones. Patients in the control group neither listened tonature sounds nor wore headphones. The Richards–Campbell sleep questionnairewas used for the evaluation of the patients’ sleep quality two days before andduring the intervention. The mean scores of sleep quality at the first two and thelast two nights, respectively, were considered as the pretest and the posttest sleepquality. Cohen’s d, one‑way analysis of variance, paired‑sample t, Chi‑square,Fisher’s exact, and the Scheffe post hoc tests were used to analyze the data.Results: Posttest‑pretest mean differences of the sleep depth, the number ofawakenings, and the returning to sleep domains of sleep quality in the controlgroup were significantly less than nature sounds group (P 0.001). Moreover, theposttest‑pretest mean differences of the total sleep quality and its sleep latencyand subjective sleep quality domains in the control group were significantly lowerthan both the nature sounds and the silence groups (P 0.001). On the otherhand, none of the differences between the nature sounds and the silence groupswere statistically significant (P 0.05). Conclusion: Both nature sounds andsilence can significantly improve sleep quality among patients in CCUs. Nursescan use these strategies to improve the sleep quality of a patient in these units.