The aim of our study was to predict hypotension by using caval aorta index and perfusion index in elderly patients who may develop hypotension after spinal anesthesia.

The study will include 200 patients over 60 years of age who are planned to undergo elective lower extremity surgery in the supine position with spinal anaesthesia. This study is planned as a single-centre prospective observational study. All patients planned to be included in the study will be fasted according to the standard protocol. Age, height, body weight, body mass index, gender, type of surgery, systemic disease, preoperative heart rate (HR), noninvasive systolic (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and peripheral oxygen saturation (SpO₂) will be measured and noted in the waiting area before entering the operating room. For the initial perfusion index (PI) value, PI measurement will be taken 3 times at 5 minutes intervals with a probe to be attached to the same finger and the average will be recorded as the initial PI value. To measure the IVC diameter, the maximum internal AP diameter of the IVC will be measured in M-mode during expiration and the mean will be taken. The maximum internal AP diameter of the abdominal aorta will be measured during systole and the mean will be recorded as the aortic diameter.The study will be explained to all patients participating in the study and informed consent will be obtained from the patients. Routine preoperative preparations and monitoring of the patients admitted to the operating room will be performed. Spinal anaesthesia will be performed through L3-4 or L4-5 intervertebral spaces in the sitting position.Depending on the nature of the patient and the type of surgery, an appropriate dose of 0.5% hyperbaric bupivacaine will be injected intrathecally to provide adequate sensory block.The patient will be immediately placed in the supine position.The level of sensory blockade will be evaluated at the end of the appropriate time. heart rate, systolic, diastolic blood pressure, mean arterial pressure, oxygen saturation and PI will be recorded every 2 minutes for the first 15 minutes, then every 5 minutes until the 30th minute, then every 10 minutes until the 60th minute and at the end of the operation.Hypotension after spinal anaesthesia will be defined as SDB less than 90 mmHg, a fall in SDB by more than 30% from the preoperative baseline value or an OAB less than 60 mmHg.Patients will be divided into two groups as patients with and without hypotension after spinal anaesthesia. Demographic data (age, gender, comorbidity, etc.), caval-aorta index and PI will be analysed for differences between the groups.

The primary aim of the study was to evaluate the ability of caval-aorta index and PI to predict post-spinal hypotension in elderly patients between the two groups.

Inclusion Criteria:

• American Society of Anesthesiology(ASA) I-II-III score
• Patients over 60 years
• Elective surgeries
• Surgeries in supine position

Exclusion Criteria:

• Patient refusal to participate in the study
• The patient will undergo emergency surgery
• Contraindication to spinal anaesthesia
• Planning unilateral spinal anaesthesia
• Failure of spinal anaesthesia
• Body mass index above 35kg/m2
• Presence of preoperative hypotension (SBP<90mmHg or MAP<60mmHg)
• The patient has valvular disease and arrhythmia impairing haemodynamics
• Presence of neuropsychiatric disorders that make communication difficult
• Presence of abdominal hernia

patients over 60 years of age who will undergo elective lower extremity surgery in supine position admitted to ankara city hospital