Introduction: Poor quality of sleep is a common problem among patients in the coronary care unit. The use of earplugs, as an uncomplicated non-pharmacological method, can improve quality of sleep in patients. This study aimed to investigate the effect of using earplugs on the quality of sleep in patients hospitalized in coronary care unit.
Methods: This study was a randomized clinical trial conducted in the coronary care unit of the hospitals affiliated to Tehran University of Medical Sciences. 72 acute coronary syndrome patients having the inclusion criteria participated in this study and written consents were obtained. Through simple random sampling, the participants were assigned to two groups of intervention and control. In the intervention group, earplugs were used for the first three nights after hospitalization for 45 minutes in the beginning of sleep. The quality of sleep was measured upon hospitalization and three days later using the Pittsburgh Sleep Quality Index. The data were analyzed by SPSS 16 using descriptive and inferential statistics (Chi-square, Fisher's exact test, independent samples t- test).
Results: The mean ± standard deviation of quality of sleep for the intervention group using earplugs decreased from 8.11±3.00 (before the intervention) to 6.00±2.30 (after the intervention). It increased from 6.33±3.08 to 8.80±2.45 for the control group. The results of independent samples t- test showed a statistically significant difference between the intervention and control groups in terms of average change in the sleep quality score before and after the intervention (p=0.001).
 Conclusion: It is recommended that nurses employ earplugs as a non-pharmacological intervention for improving the quality of sleep of patients in the cardiac care unit.