Bariatric surgical procedures are associated with low short-term mortality and may be associated with long-term reductions in all-cause, cardiovascular, and cancer-related mortality. This surgeries are major surgeries include risk of mortality still.

Different level anxiety that can define as fear or worry can be seen in 60%-80% of patients scheduled surgery. Anxiety levels; may vary on age, gender, type of operation, previous experience of anesthesia and surgery and way of hospitalization. Preoperative anxiety affects negatively the surgery, the anesthesia and postoperative recovery.

Melatonin is a hormone secreted from the pineal gland. The circadian rhythm of melatonin changes according to age and it's production decreases with older ages. Melatonin is an antioxidant, antinociceptive, hypnotic, anticonvulsant, neuroprotective, anxiolytic, sedative, analgesic and has a preventive effect of delirium in intensive care. Irregularity of melatonin secretion causes a sleep irregularities, psychosis in intensive care unit and some behavioral disorder. It has been demonstrated that oral exogen administration of melatonin was effective on preoperative anxiety.

The aim of this study was to determine the relationship between endogenous melatonin levels and anxiety levels in patients with bariatric surgery.

Bariatric surgical procedures, including gastric bypass, vertical sleeve gastrectomy, and biliopancreatic diversion, are the most effective and durable treatments for obesity. Bariatric surgery provides long-term benefit for patients with diabetes, fatty liver disease, and other metabolic disorders, through both weight loss-dependent and -independent mechanisms.

Bariatric surgery is associated with low short-term mortality and may be associated with long-term reductions in all-cause, cardiovascular, and cancer-related mortality. This surgeries are major surgeries include risk of mortality still.

Different level anxiety that can define as fear or worry can be seen in 60%-80% of patients scheduled surgery. Anxiety levels; may vary on age, gender, type of operation, previous experience of anesthesia and surgery and way of hospitalization. Preoperative anxiety affects negatively the surgery, the anesthesia and postoperative recovery. It may cause the pathophysiological response as hypertension and arrhythmia even refusal the surgery is planned. Also the anesthetic requirements and the risk "awareness" during the operation may increase. Patients with high level anxiety have more postoperative pain symptoms too. Therefore determination of the causes and prevention of anxiety is important.

Melatonin is a hormone secreted from the pineal gland, also known as the pineal gland. It's production is stimulated by darkness, independent of sleep, and is inhibited by exposure to light and proved endocrine rhythms. It shows a daily biorhythm. The circadian rhythm of melatonin changes according to age and it's production decreases with older ages. Melatonin level can be measured in the blood and in urine collected for 24 hours. Melatonin is an antioxidant, antinociceptive, hypnotic, anticonvulsant, neuroprotective, anxiolytic, sedative, analgesic and has a preventive effect of delirium in intensive care. Irregularity of melatonin secretion causes a sleep irregularities, psychosis in intensive care unit and some behavioral disorder. It has been demonstrated that oral exogen administration of melatonin was effective on preoperative anxiety.

The aim of this study was to determine the relationship between endogenous melatonin levels and anxiety levels in patients with bariatric surgery.

Inclusion Criteria:

American Society of Anesthesiologists (ASA) 3-4 status, aged between 18-65 years who are scheduled to undergo bariatric surgery.

Exclusion Criteria:

Patients with cardiovascular and pulmonary disease, those with ASA III-IV and propofol, fentanyl, remifentanil and rocuronium allergy.

50 patients of American Society of Anesthesiologists (ASA) 1-2 status, aged between 18-65 years who are scheduled to undergo bariatric surgery, will be included in the study.

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