This study aims to compare lumbosacral erector spinae plane block and psoas muscle compartment with sciatic nerve block in unilateral lower limb operations in critically ill patients.

The lower limb surgeries are associated with acute postoperative pain and require long-term analgesia. Regional anesthesia is often used to prevent postoperative pain. Ultrasound-guided regional anesthetic approaches provide a simple intraoperative pathway that lowers pain scores with less impact on the respiratory or cardiovascular system.

Psoas compartment block (PCB) is a peripheral regional technique of anesthesia, which provides a block of the main components of the lumbar plexus - the femoral, lateral cutaneous nerve of the femur and sciatic nerve. In combination with the sciatic nerve block, the psoas compartment block provides effective anesthesia of the entire lower extremity, with better hemodynamic stability.

The erector Spinae plane block (ESPB) is a novel regional block technique primarily introduced in 2016 for managing severe neuropathic pain.

• Age from 18 to 65 years.
• Both sexes.
• American Society of Anesthesiology (ASA) physical status III, IV.
• Critically ill patients admitted to intensive care unit.
• Undergoing unilateral lower limb operations.

Exclusion Criteria:

• History of allergy to local anesthetics.
• Bleeding tendency.
• Coagulopathy.
• Anticoagulant therapy.
• Pre-existing psychological, neurologic, and spinal cord diseases.
• Previous back surgery.
• Infection or mass at the site of the block.
• Chronic analgesic therapy.
• Severe cardiac or renal diseases.

The data will be available upon a reasonable request from the corresponding author after the end of study for one year.

After the end of study for one year.

The data will be available upon a reasonable request from the corresponding author.