Duration of Analgesia after Ultrasound-Guided Brachial Plexus Block with Perioperative Intravenous Dexamethasone for Upper Limb Surgery: A Prospective Observational Study

Abstract

Background: Brachial plexus blocks are widely used for perioperative anaesthesia and postoperative analgesia in upper limb surgery. Interscalene, supraclavicular and axillary approaches are selected according to the anatomical site of surgery, while adjuvants such as dexamethasone are commonly used to prolong analgesic duration and reduce rescue analgesic requirement.

Objective: To evaluate block characteristics, duration of analgesia, postoperative pain scores, 24-hour opioid requirement, patient satisfaction and early adverse events among patients receiving ultrasound-guided interscalene, supraclavicular or axillary brachial plexus blocks with perioperative intravenous dexamethasone.

Materials and Methods: This prospective observational study included 60 patients undergoing upper limb surgery. Twenty patients each received interscalene, supraclavicular or axillary brachial plexus block according to surgical site. Study period: 2023-2025. All patients received 0.5% bupivacaine, with local anaesthetic volume determined by block approach. Dexamethasone 8 mg was administered intravenously immediately after block placement. Postoperative analgesia included intravenous paracetamol 1 g every 8 hours, with intravenous tramadol 50 mg as rescue analgesia when the numerical rating scale pain score was ≥4. Recorded outcomes included block performance time, sensory and motor onset, duration of analgesia, pain at rest at 6, 12, 24 and 48 hours, 24-hour opioid consumption in morphine-equivalent dose, satisfaction score, block success and adverse events.

Results: The mean age was 47.20±16.88 years, and 30 patients were male. Each block group included 20 patients, with equal male and female representation. Mean duration of analgesia was 20.54±3.87 hours in the interscalene group, 20.01±4.42 hours in the supraclavicular group and 20.59±4.72 hours in the axillary group (p=0.899). Pain scores remained low during the first 48 postoperative hours. Median 24-hour opioid requirement was 3 mg morphine equivalent in all three groups. Block success was achieved in all 60 patients. Hoarseness was significantly more frequent after interscalene block (p=0.046), while Horner syndrome showed a higher but statistically non-significant frequency in the interscalene group.

Conclusion: Ultrasound-guided brachial plexus blocks with perioperative intravenous dexamethasone provided effective postoperative analgesia for upper limb surgeries, with approximately 20 hours of analgesic duration, low early pain scores, limited opioid requirement and high patient satisfaction. The analgesic profile was broadly comparable across the three approaches, although hoarseness and Horner syndrome were observed more often after interscalene block.