D5W) has long been used as an intravenous fluid for hydration and energy supplementation and has recently gained increasing clinical interest in perineural injection therapies and ultrasound-guided hydrodissection. D5W has been shown to improve pain and functional outcomes in entrapment neuropathies by mechanically releasing perineural adhesions and potentially modulating neurogenic inflammation. In contrast, 0.9% sodium chloride (normal saline) is routinely used as a dilution medium for local anesthetics in peripheral nerve blocks; however, emerging evidence suggests that alternative diluents such as D5W may influence block onset and efficacy.
The infraclavicular block is a commonly used ultrasound-guided technique for brachial plexus anesthesia, providing reliable anesthesia and postoperative analgesia for upper extremity surgery. This study aims to compare the effects of diluting bupivacaine with either D5W or 0.9% NaCl on block success and duration of analgesia in patients undergoing infraclavicular block. Secondary outcomes include block onset characteristics, sensory and motor block profiles, and perioperative analgesic requirements. The findings may help determine whether D5W represents a safe and effective alternative diluent to saline in routine regional anesthesia practice.
Patients who agree to participate in the study and provide written informed consent
Patients scheduled for elective upper extremity surgery for whom infraclavicular block is considered appropriate for anesthetic management
Age between 18 and 65 years
American Society of Anesthesiologists (ASA) physical status I-III
Patients who decline to participate in the study or refuse to provide informed consent
History of allergy or hypersensitivity to study medications
Body mass index (BMI) ≥ 30 kg/m²
Body weight less than 40 kg
Parallel
Blocked and analgesia time
Diagnostic testAll eligible participants will be informed in detail about the study objectives, procedures, potential risks, and benefits by the responsible investigator, and all questions will be answered prior to enrollment. Written informed consent will be obtained from each participant before any study-related procedures are initiated. Following the ultrasound-guided infraclavicular block, sensory block assessment will be performed using a sterile single-use needle for a pinprick test. Light punctate stimuli will be applied to dermatomal areas corresponding to the branches of the brachial plexus on the blocked extremity. Participants will be asked to compare the sensation with the contralateral limb and to report the perceived sensation as "normal," "reduced," or "absent." Sensory block assessments will be performed at 5, 10, 15, 20, and 30 minutes after block administration. Sensory block onset time will be defined as the time point at which the participant reports absence of pinprick sensation
Sensory block onset time
Sensory block onset time will be defined as the time from completion of the ultrasound-guided infraclavicular block until the participant reports complete loss of pinprick sensation in the dermatomal areas corresponding to the branches of the brachial plexus, assessed using a sterile pinprick test.
Motor block duration
Motor block duration will be defined as the time from onset of motor block (Modified Upper Extremity Bromage Scale ≥1) until full recovery to Bromage score 0.
Intraoperative need for additional anesthetic or analgesic intervention
Requirement for supplemental anesthetic or analgesic interventions during surgery will be recorded as a binary outcome (yes/no) and as total additional drug consumption if applicable.
Postoperative analgesic efficacy
Postoperative pain intensity will be assessed using the Visual Analog Scale (VAS; 0 = no pain, 10 = worst imaginable pain) at postoperative 2, 6, 12, and 24 hours.
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Burçin Alaçam, MD
Lead sponsor
Sakarya University
Sponsor institution
