Cardiovascular diseases (CVD) are among the most common leading causes of death worldwide. Among cardiovascular diseases, coronary artery disease (CAD) is an important health problem that is the most common and causes death. Medical treatment and revascularization have an important place among the treatment methods of CAD. Revascularization is performed with stenting and/or coronary artery bypass surgery (CABC) according to the patient's clinic and coronary artery lesions. CABC in the world is generally performed using open heart surgery heart-lung pump. Open heart surgeries aim to reduce mortality and morbidity and improve quality of life. Despite all the scientific and technological developments in open heart surgery, some patients may have physical and psychological recovery problems. The patients' own heart problems and information about the heart from the environment; It causes intense fear of death and anxiety in some of the individuals who will undergo heart surgery in the pre- and post-operative period. Revealed in this process; Persistent symptoms may occur due to anxiety, stress, depression, pain, fatigue, and sleep disorders. It may not always be possible to effectively eliminate these complications with pharmacological treatments. Cognitive-Behavioral Therapy (CBT) can be an alternative to pharmacological treatment, and it can be applied together with drugs to help resolve problems. CBT is a proven and accepted psychotherapeutic method based on clinical experience, theory and research. There are three categories of CBT. The first is the origin of behavioral therapy; The second is based on theories about thoughts and their effects on the body, emotions, and actions (cognitive therapy), while the third category of CBT (acceptance and commitment therapy), metacognitive therapy, and mindfulness-based therapy are based on acceptance. The focus in cognitive therapy is on which thought and behavioral patterns of the patient can create and perpetuate existing problems and affect functional levels. It can manage the level of depression and anxiety by changing thought and behavior patterns. One of the common neurofunctional complications after cardiovascular surgery is delirium. Delirium manifests as a disturbance of consciousness and attention accompanied by changes in cognitive function or perceptual impairment. Delirium is characterized by acute onset and recurrent fluctuations. Patients who need constant monitoring and care in the intensive care unit after open heart surgery find themselves surrounded by medical and technological equipment. Many factors such as sedation, environmental factors, illness and mechanical ventilation affect the incidence of anxiety and delirium by causing sleep disturbance and confusion in the concepts of day and night in patients hospitalized in the intensive care unit. It is assumed that reducing environmental factors such as excessive noise and alarms and exposure to artificial light in intensive care can improve the patient's sleep quality. In this respect, it is thought that the use of earplugs and eye masks will be effective measures in patients. Considering that the cause of delirium is multifactorial, it is recommended that nurses integrate it into care by reducing pain, providing orientation, meeting sensory motor requirements such as glasses and hearing aids, maintaining biological sleep patterns, and reducing anxiety. In this context, it is thought that CBT and eye mask, ear plug applications, which are non-pharmacological psychosocial nursing interventions, can be used as an independent nursing intervention to improve sleep quality and prevent anxiety and delirium. In addition, melatonin and cortisol hormones both play a role in regulating the sleep-wake cycle. The core area of delirium is represented by the disruption of sleep. In this respect, the post-operative blood melatonin and cortisol levels of the patients will be examined as secondary outcomes of the study.