This study aims to evaluate perioperative hemodynamic changes using the inferior vena cava (IVC) collapsibility index in patients undergoing lumbar stabilization surgery under general anesthesia. The IVC diameter and collapsibility index will be measured using ultrasonography at predefined perioperative time points. Hemodynamic parameters such as blood pressure and heart rate will also be recorded. The study seeks to determine whether the IVC collapsibility index can be used as a non-invasive indicator of intravascular volume status and hemodynamic changes during lumbar spine surgery.

his prospective study aims to evaluate perioperative hemodynamic changes using the inferior vena cava (IVC) collapsibility index in patients undergoing lumbar stabilization surgery under general anesthesia in the prone position. The inferior vena cava diameter will be measured using ultrasonography at different perioperative time points, including the preoperative period, after induction of anesthesia, and before extubation.

The IVC diameter and collapsibility index will be recorded and analyzed to assess changes in intravascular volume status during the perioperative period. In addition to ultrasonographic measurements, hemodynamic parameters such as blood pressure and heart rate will be monitored and recorded.

The study aims to investigate whether the IVC collapsibility index can be used as a non-invasive indicator of intravascular volume status and perioperative hemodynamic changes in patients undergoing lumbar spine surgery.

Inclusion Criteria:

• Age ≥ 18 years
• Patients classified as ASA physical status I-II-III
• Patients scheduled for elective lumbar spine stabilization surgery under general anesthesia
• Ability to obtain adequate inferior vena cava (IVC) ultrasonographic imaging
• Provision of written informed consent

Exclusion Criteria:

• Age younger than 18 years

  • Emergency surgery
  • American Society of Anesthesiologists (ASA) physical status IV
  • Patients undergoing revision lumbar stabilization surgery
  • Baseline systolic blood pressure >180 mmHg or <90 mmHg
  • Heart failure with ejection fraction (EF) <40%
  • Pulmonary artery pressure (PAP) >40 mmHg
  • Presence of intra-abdominal mass, ascites, or increased intra-abdominal pressure
  • Body mass index (BMI) >30 kg/m²
  • Pregnancy
  • Patients with neurological or psychiatric disorders
  • Inability to obtain adequate inferior vena cava (IVC) ultrasonographic imaging
  • Refusal to provide written informed consent

Adult patients (≥18 years) scheduled for elective lumbar spine stabilization surgery under general anesthesia at Trabzon University Faculty of Medicine Hospital will be included in this study. All participants will be classified as ASA physical status I-II-III and will undergo surgery in the prone position. Inferior vena cava (IVC) diameter and collapsibility index will be measured using ultrasonography at predefined perioperative time points.

Individual participant data will not be publicly shared because the dataset contains patient-level clinical information collected during routine clinical care. Data may be available from the investigators upon reasonable request and with approval from the institutional ethics committee.