Cardiovascular disease is the leading cause of death worldwide [1]. It is a common and life-threatening problem in developed and developing countries in men and women [2]. In developed countries, 50% of deaths annually or 5 million out of 12 million deaths are due to cardiovascular disease [3]. The Middle East and Eastern Europe have the highest mortality rates for cardiovascular disease [4]. In Iran, cardiovascular disease is currently the leading cause of death and the prevalence of coronary artery disease and its complications in the community cause mortality and disability of a large part of the country's productive forces, especially in the best years of work efficiency and reduced productivity. There has been an increase in medical costs [5].
Coronary artery bypass graft surgery can relieve angina symptoms in patients, but sometimes these patients experience symptoms of pain, mental distress and sleep problems [6]. Problems and complications after coronary artery bypass graft surgery may include pain in the area of chest and leg incision, fatigue, anxiety, depression, anger, irritability, and sleep disturbances that have been reported by patients many times [7-10].
Currently, medicinal methods are being used to improve the quality of sleep in cardiac patients [19], but many of these hypnotic drugs are associated with some side effects, such as resistance to medication and withdrawal symptoms [21–20].
Relaxation is one of the nursing interventions that has been introduced in many sources as complementary and sometimes alternative therapies to improve the sleep quality of patients [24-23]. Commonly used relaxation techniques include Benson relaxation, progressive muscle relaxation, relaxation with meditative mental imagery, massage, hypnosis, breathing technique, yoga and music therapy [29-26].
According to the results of the study by Akbarzadeh et al., Benson relaxation technique as a complementary treatment can increase sleep quality in chronic heart patients [34]. Also, according to Haddadian et al., progressive relaxation technique can be effective in improving sleep quality of hemodialysis patients [35], but few studies have been performed on the effect of Benson relaxation technique on patients' sleep quality; therefore this study aimed to evaluate the quality of sleep of patients after coronary artery bypass graft surgery.

 

In the present randomized clinical trial study, 80 patients [36] after coronary artery bypass graft surgery were selected from patients referring to cardiac surgery ward of Shahid Beheshti hospital and Hazrat Vali-e-asr hospital of Qom according to the researcher's criteria in mind and using randomizing software were divided into two groups of four: A (Benson relaxation group) and B (control group). Criteria for entering the sample included 40-75 years of age, having written informed consent, having no cardiac surgery history, having no mental illness, undergoing coronary artery bypass graft due to 2VD-3VD, having complete alertness and hearing ability and a good word to learn about sedation is poor sleep quality based on the Pittsburgh Sleep Quality Questionnaire (score 5-21 is considered to be poor sleep quality) [26], and using non-sedative medications other than routine medications. Patients were excluded from the present study if they applied any of the relaxation methods except Benson during the study period and the patient's unwillingness to participate in the study.
Data were analyzed using independent t-test, paired t-test, analysis of variance, Mann-Whitney, Wilcoxon, Kruskal-Wallis, and Chi-square using SPSS software (SPSS Inc., Chicago, Illinois, USA).

Based on the results of this study, the mean age of the subjects was 62.5±6.6. In Table 1, the individual characteristics of the present study’s samples are presented. Before intervention, there were no significant differences between two groups of Benson relaxation and control group in any variables of sleep quality and total sleep quality (P>0.05) (Table 2). After intervention, in the Benson relaxation group, the patients' sleep quality was significantly better than the control group in terms of subjective sleep quality, sleep latency, sleep efficacy, sleep disturbances and total quality (P<0.05) (Table 3). However, there was no significant difference between Benson relaxation and control group in the variables of sleep duration, taking sleep drugs and daily dysfunction (P>0.05) (Table 4).
 

Table 1. Distribution of absolute and relative frequency of individual characteristics of patients in this study


Table 2. Mean scores of sleep quality domains of patients before intervention in Benson relaxation and control group


Table 3. Comparison of mean scores of sleep quality domains after intervention in Benson relaxation group and control group


Table 4. Comparison of mean total sleep quality before and after intervention in Benson relaxation group and control group

According to the results of this study, after intervention, sleep quality was improved in most dimensions and overall sleep quality in both test and control groups, but this improvement was higher in Benson relaxation group than control group. In other words, the sleep quality of Benson's patients was better than the control group in the areas of subjective sleep quality, delayed onset of sleep, useful sleep, sleep disturbances and overall quality of sleep, but in the areas of hypnotic drugs and impaired daily functioning, there was no significant difference between the two groups.

 

Using Benson's relaxation technique as supplementary and alternative therapies to improve the sleep quality of patients after open heart surgery is recommended.

 

This article is part of a postgraduate thesis approved by the Graduate Council of Shahroud University of Medical Sciences in 2016, with respect to the right of authors to use printed and electronic texts and resources, and was approved by research project at the University Ethics Committee under the IR.SHMU Code of Ethics. REC.1396.163 and is registered at the Iranian registry for clinical trials center under the code IRCT201703123064N6. We would like to express our gratitude for the financial support of this university in the implementation of this research project, as well as for the cooperation and assistance of medical and nursing staff and patients of Cardiac Surgery Department of Shahid Beheshti Hospital and Hazrat Vali-e-asr Hospital in Qom.

 

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.