Aim of the study:

The current study aims to compare the effect of adding dexamethasone versus magnesium sulfate to bupivacaine in ultrasound-guided erector spinae plane block on the severity of postoperative pain.

Primary Objectives:

- To compare the effect of ESPB without additives to the effect of adding dexamethasone and to the impact of adding magnesium sulfate in the form of post-operative morphine consumption

Aim of the study:

The current study aims to compare the effect of adding dexamethasone versus magnesium sulfate to bupivacaine in ultrasound-guided erector spinae plane block on the severity of postoperative pain and postoperative morphine consumption.

Methodology:

I. Study design:

This is a randomized Controlled Study. It will involve three groups: Control Group (C) receiving erector spinae block with 27ml bupivacaine 0.25% + 3 ml NS, Group (M) receiving 27 ml bupivacaine 0.25% + 3 ml magnesium sulphate 10%, Group (D) receiving 27 ml bupivacaine 0.25% + 8 mg dexamethasone (2 ml) + 1 ml NS.

II. Study setting and location:

National Cancer Institute, Cairo University after approval by the institutional review board.

III. Study population:

Adult patients undergoing unilateral nephrectomy under general anesthesia.

Patients will be randomly assigned to the groups using online random number generator.

Erector Spinae Plane Block technique:

Informed consent, including the risks and benefits of the procedure, should be obtained before carrying out an ESP block. A peri-procedural "timeout" should be performed to confirm the type, side, and location of the procedure and ensure that there are no contraindications.

Standard patient monitoring should be in place, including continuous ECG monitoring, pulse oximetry, and blood pressure measurement in at least 5-minute intervals. Patients should be prepped and draped in sterile conditions. Sterile gloves and surgical cap and a mask are necessary, and the ultrasound probe is placed into the sterile ultrasound probe cover for imaging. The ESP block will be performed at the level of T 10 paraspinal level. The ultrasound transducer should be placed in a cephalocaudal orientation over the midline of the back at the desired level. The probe should then slowly be moved laterally until the transverse process is visible. The transverse process requires differentiation from the rib at that level. The transverse process will be more superficial and wider, while the rib will be deeper and thinner. Erector spinae muscle should be identified superficial to the transverse process. The needle should be inserted superior to the ultrasound probe using an in-plane approach in the cephalad to caudal direction. Once the needle tip is below the erector spinae muscle, a small bolus of local anesthetic should be given through the needle. The erector spinae muscle should be visualized, separating from the transverse process. This separation from the transverse process confirms the proper needle position.

The local anesthetic should then be injected in 5 ml increments, with aspiration after every 5 ml to prevent intravascular injection. Block will be performed preoperatively in the preoperative holding area.

Heart rate and blood pressure to be recorded preoperative, intraoperative and postoperatively

Assessment of pain:

Pain assessment will be done through Visual Analogue Scale. Patients should be informed preoperatively about it and how to use this scale. Starting from recovery time, pain assessment is done by asking the patient to mark the intensity of pain perceived and express it on a 10 cm horizontal scale ranging from no pain at one end to the worst possible pain at the other end.

Assessment of pain is to be done in the recovery unit and at 0,2,4,8,12,18, 24 and 30 hours postoperatively.

Total amount of opioid needed in first 24 hours to be recorded.

Rescue Analgesia:

Intraoperative rescue analgesia will be done by giving fentanyl at dose of 1 mic/Kg. Postoperatively, NSAIDs such as Ketorolac 30 mg I.V infusion if VAS is between 3 to 6, and Morphine 3 mg I.V if VAS equals or is more significant than 6.

Inclusion Criteria:

• Adult (18 - 65)
• Patients undergoing unilateral nephrectomy
• ASA II / III

Exclusion Criteria:

• Patient refusal
• Age less than 18 years
• Allergy to any of the studied medications
• Mid line incision
• Bilateral nephrectomy
• Distorted anatomy of the back (e.g. kyphoscoliosis)
• Known neurologic disorders, psychiatric disorder or chronic pain
• Local infection
• Hemodynamic instability

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