The aim of this study was to compare the effects of hypobaric and hyperbaric spinal applications on patient haemodynamics, duration of anaesthetic effect and postoperative analgesia. Thus, it was aimed to determine the method that protects haemodynamics more and suppresses postoperative pain complaints of patients better in this patient group with advanced age, comorbid systemic diseases and high risk of operation.

Patients who are planned to be operated for partial hip replacement at Adıyaman University Training and Research Hospital, who are informed about the study and who agree to participate in the study with their written consent will be included in the study.

Patients who agree to participate in the study will be divided into two groups: hypobaric and hyperbaric spinal anaesthesia patients will be divided into two groups to be decided by the Anaesthesiology and Reanimation specialist responsible for the operation (hyperbaric/hypobaric). Before the start of the operation, perfusion index (PI) values will be monitored with a probe in both lower extremities with standard ASA monitoring. Haemodynamic values (blood pressure arterial, peak heart rate, peripheral oxygen saturation), PI values of both extremities, duration of motor and sensory block, postoperative numeric pain scores of all patients will be recorded and these values will be compared in both groups.

Thus, it was aimed to compare the efficacy, safety, block times and contribution to pain management of each application.

Inclusion Criteria:

• ASA I-II
• 18-65 aged

Exclusion Criteria:

• ASA III-IV
• Deny to participiate
• conditions that spinal anesthesia contraindicated
• use of alpha or beta-blockers
• allergy to local anesthetics
• diabetes mellitus
• peripheral vascular disease (The following exclusion criteria were added to ensure patient safety and to avoid confounding factors that could interfere with perfusion index measurements or hemodynamic responses: use of alpha or beta-blockers, diabetes mellitus, and peripheral vascular disease. These conditions may significantly alter autonomic regulation, vascular tone, or peripheral circulation, potentially affecting perfusion index values or increasing the risk of adverse reactions to spinal anesthesia)

for patient - closed envelope system for Outcomes Assessor - will not participate perioperative period and will not know group of patients