Intravenous Dexamethasone Added to Dexmedetomidine After Superior Trunk Block

Effective postoperative analgesia after arthroscopic shoulder surgery is important for patient comfort, early mobilization, and reduction of postoperative complications. Interscalene brachial plexus block is widely used for shoulder surgery; however, it may be associated with hemidiaphragmatic paresis and respiratory complications. Superior trunk block has been proposed as an alternative regional anesthesia technique that may provide effective analgesia with a potentially lower risk of respiratory impairment.

Adjuvant agents are frequently used to prolong the duration and improve the quality of analgesia after peripheral nerve blocks. Intravenous dexamethasone has been shown to prolong analgesia and improve postoperative pain control. Dexmedetomidine is another adjuvant agent with sedative and analgesic properties. However, evidence regarding the combined use of intravenous dexamethasone and intravenous dexmedetomidine in patients receiving superior trunk block for arthroscopic shoulder surgery is limited.

This study is designed as a prospective, randomized, placebo-controlled, triple-blind clinical trial. Adult patients aged 18 to 65 years, classified as American Society of Anesthesiologists physical status I to III, scheduled for elective arthroscopic shoulder surgery, and eligible for superior trunk block will be included after written informed consent.

All patients will receive standard monitoring before block placement. Premedication with intravenous midazolam may be administered for anxiolysis. A superficial cervical plexus block will be performed with 3 mL of 0.5% bupivacaine, followed by ultrasound-guided superior trunk block using 15 mL of 0.5% bupivacaine. Block success will be assessed approximately 20 minutes after block completion using sensory and motor evaluation.

Participants will be randomly assigned to one of two groups using a computer-generated randomization sequence and sealed opaque envelopes. In the intervention group, patients will receive standard intravenous dexmedetomidine infusion plus intravenous dexamethasone 0.15 mg/kg. In the control group, patients will receive standard intravenous dexmedetomidine infusion plus an equal volume of 0.9% normal saline placebo. The study drug or placebo will be prepared by an independent staff member who will not be involved in block performance, data collection, or outcome assessment. The patient, block practitioner, postoperative outcome assessor, and statistician will remain blinded to group allocation.

All patients will receive a standardized postoperative multimodal analgesia protocol. Intravenous ibuprofen 400 mg will be administered every 8 hours. Intravenous tramadol 50 mg will be used as rescue analgesia when the Numeric Rating Scale pain score is greater than 3 at rest or during passive movement, or when the patient requests additional analgesia. At least 4 hours will be allowed between tramadol doses, and the maximum daily tramadol dose will be limited to 400 mg.

The primary outcome is the time from completion of the superior trunk block to the first request for systemic rescue analgesia in the postoperative period. Secondary outcomes include sensory and motor block characteristics, postoperative Numeric Rating Scale pain scores at 4, 8, 12, 24, and 72 hours, incidence of rebound pain, cumulative opioid consumption during the first 24 hours, perioperative blood glucose levels, hemodynamic events requiring treatment, postoperative nausea and vomiting, sleep disturbance due to pain during the first two nights, transient block-related complications such as Horner syndrome, hoarseness or dyspnea, and patient satisfaction at postoperative 72 hours.

Inclusion criteria

Patients aged 18 to 65 years. Patients classified as American Society of Anesthesiologists physical status I to III.

Patients scheduled for elective arthroscopic shoulder surgery. Patients with a body mass index between 18.5 and 35 kg/m². Patients who are able to understand the study protocol and provide written informed consent.

-

Exclusion criteria

Patients younger than 18 years or older than 65 years. Patients classified as American Society of Anesthesiologists physical status IV or higher.

Contraindications to peripheral nerve block, including coagulopathy or infection at the block site.

Known allergy or contraindication to any of the drugs used in the study. Active gastrointestinal bleeding, history of peptic ulcer disease, or severe renal or hepatic insufficiency.

History of chronic analgesic or opioid use. Pregnancy or breastfeeding. Presence of coagulopathy or use of anticoagulant or antiplatelet therapy. Requirement for additional sedation or general anesthesia during surgery. Neurological or psychiatric disease that may affect pain assessment.

-