This study aims to evaluate the effects of prone positioning on oxygenation, ventilation, and hemodynamic parameters in patients undergoing posterior stabilization surgery under general anesthesia. By comparing routine anesthesia and monitoring data obtained in the supine and prone positions, the study seeks to determine how positional changes influence respiratory mechanics and perioperative physiological stability.

The prone position is frequently used during posterior stabilization surgery, yet it is associated with important physiological changes that may affect both respiratory and hemodynamic function under general anesthesia. Previous studies have shown that prone positioning may improve ventilation-perfusion matching, increase functional residual capacity, and enhance oxygenation. At the same time, position-related alterations in thoracic mechanics, airway pressures, venous return, and cardiovascular parameters may influence intraoperative management.

This study is designed to comprehensively assess the physiological effects of prone positioning in anesthetized patients undergoing posterior stabilization surgery. Routine anesthesia and monitoring data collected during mechanical ventilation will be analyzed and compared between the supine and prone positions. Particular focus will be placed on oxygenation, ventilation variables, respiratory mechanics, and hemodynamic parameters in order to evaluate the impact of positional change.

In addition, the study aims to identify which clinical and monitoring findings should be prioritized during anesthetic management of patients in the prone position. By clarifying the relationship between positioning and perioperative physiological responses, the study seeks to contribute to safer anesthetic practice and to support the maintenance of adequate oxygenation and hemodynamic stability throughout surgery.

Inclusion Criteria:

Patients aged 18 to 75 years Patients classified as ASA physical status I, II, or III according to the American Society of Anesthesiologists Patients undergoing posterior stabilization surgery Patients who voluntarily agreed to participate in the study Patients with a body mass index (BMI) <35 kg/m² Patients followed with a standard mechanical ventilation procedure

Exclusion Criteria:

• - ASA 4 olarak değerlendirilenler
• Anestezik ajan alerjisi olanlar
• Kanama diatezi bozukluğu olanlar
• Cerrahi süresi 3 saatin üstünde olanlar
• Bilinen ileri akciğer hastalığı olanlar (intertisyel akciğer hastalığı, ileri düzey KOAH, ileri düzey astım vb)
• VKI≥35 olanlar
• Obstrüktif uyku apne sendromu tanısı olanlar
• Toraks deformitesi olanlar
• Ciddi kalp yetmezliği öyküsü olanlar (EF<30)
• Şiddetli anemi öyküsü olanlar (Hg<8 mg/dl)
• Cerrahi operasyon sırasında kan transfüzyonu ihtiyacı olan hastalar

the study population consists of women reproductive age (18-80 years ) who are sheduled to undergo Posterior Stabilization Surgery under general anesthesia.

This study will not share individual participant data. Data will be collected and analyzed solely for research purposes and will remain confidential in accordance with institutional and ethical guidelines