The aim of this observational study is to compare the effects of preoperative breathing exercises during the preoxygenation period in patients undergoing abdominal surgery.

Patients who are planned for abdominal surgery under elective conditions and who meet the inclusion criteria will be divided into 2 groups after routine preoperative preparations. The 1st group will start at least 5 days before the preoperative period and until the preoperative period, a minimum of 5 minutes of effective triflo exercise will be performed 4 times a day under the supervision of a nurse, and the 2nd group (control group) will not be exercised except for routine preoperative preparation. Age, existing chronic diseases, body mass index, haemoglobin levels, smoking status, presence or absence of lung disease, SpO2 values before and at the end of respiratory exercise (in the preoperative respiratory exercise group) will be recorded. All patients will be monitored with ECG, SpO2, non invasive blood pressure, Masimo. After the patients are taken to the operating table, they will be preoxygenated with oxygen at FiO2 100% at 10 L\min in supine position, with the anaesthesia mask placed on the patient's face so that there is no leakage. Patients will be preoxygenated until ETO2 concentration reaches 85%. When preoxygenation is started, the timer will be started and the time to reach ORI:0.55 and the time to reach ETO2 85% will be measured and recorded with a timer. Preoxygenation time will be limited to a maximum of 5 minutes and patients who do not reach ETO2 concentration 85% or ORI:0.55 within 5 minutes will be noted.

Inclusion Criteria:

• Patients who will undergo elective abdominal surgery under general anesthesia
• Between the ages of 18-65
• Both genders
• ASA I-III risk group
• Patients who accept and give consent to participate in the study

Exclusion Criteria:

• Patients who did not agree to participate in the study
• Patients younger than 18 years old and older than 65 years old
• Patients with advanced heart failure
• Conditions where the patient is uncooperative (e.g. dementia, Alzheimer's)
• Patients who refuse to breathe through the mask before EtO2 reaches 85% or more after the preoxygenation process begins
• Patients who cannot reach the EtO2 level of 85% within five minutes
• Deeply Anemic Patients (Hb<8 gr/dl)
• Patients with neurological sequelae
• Patients with conditions that may prevent effective preoxygenation (those with long beards, patients with a nasogastric tube, etc.)

Patients who will undergo elective abdominal surgery under general anesthesia in Ankara Bilkent City Hospital Operating Room, between the ages of 18-65, both genders and ASA I-III risk group who agree to participate in the study will be included.