The patient undergoing bariatric surgery to pass the postoperative period without any problems depends on the complete preoperative preparation. First of all, the height and weight of the patients are measured and the body mass index is calculated. Additional diseases that may occur in patients are investigated (such as diabetes, hypertension, heart and respiratory diseases).

If the patient smokes, it is recommended to quit at least one month before the surgery. The patients' eating habits, obesity processes, and treatments related to this are determined and recorded.

Patients are evaluated with a multidisciplinary approach by bariatric surgeons, cardiologists, psychologists, pulmonologists and endocrinologists. At the end of these evaluations, bariatric surgery is performed. Patients are evaluated by a dietician in the preoperative period, appropriate diets are given, and breathing exercises are applied by specialists when necessary.

The surgical procedure to be applied to the patient by the bariatric surgeon should be explained in depth, the expected benefit and the risks that may occur should be explained.

The tests applied to the patients are as follows:

o Full blood count

o Liver function tests, lipid profile, urea/creatinine, electrolytes, iron, ferritin

o PTH, Vitamin D, Vitamin B12, Folic acid, Albumin, Ca/P

o Cortisol, Thyroid hormones, Hemoglobin A1C

o Chest X-ray

o Electrocardiogram (ECG), and Echocardiogram if necessary

o Pulmonary function tests

o Abdominal ultrasonography

o Upper gastrointestinal system endoscopy