The purpose of this study was to determine the minimum effective dose of a local anesthetic for proper anesthesia for popliteal sciatic nerve block under ultrasound guidance in patients undergoing surgery for diabetic foot disease.
Unlike general patients, patients with diabetic foot disease often have diabetic neuropathy and thus have increased sensitivity to local anesthetics. Therefore, when performing sciatic nerve block, it is essential to properly adjust the dose to prevent neurotoxicity and delay in recovery due to local anesthetics. If the appropriate effective dose of local anesthetic for sciatic nerve block is found in patients with diabetic foot through this study, it is expected that it will be a useful basis for establishing a safe anesthetic method in the case of diabetic foot surgery.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
45
Maintain the same concentration of ropivacaine used in the previous participant with an 89% chance through a random assignment
Decrease ropivacaine concentration by 0.05% from the concentration used in the previous participant with an 11% chance through a random assignment
Seoul National University Hospital
Seoul, South Korea
Median effective anesthetic concentration 90 (MEAC 90)
Concentration of ropivacaine required for successful sciatic nerve block in 90% of all patients
Time frame: within 30 minutes from the popliteal sciatic block
Median effective anesthetic concentration 50 (MEAC 50)
Concentration of ropivacaine required for successful sciatic nerve block in 50% of all patients
Time frame: within 30 minutes from the popliteal sciatic block
Sensory block onset time
Check for sensory blockade every 5 minutes until 30 minutes after block performed. For sensory block, cold sense using alcohol swabs is evaluated on the foot, comparing with the opposite foot, on a 3-point scale (0 points if there is no cold sense at all, 1 point if there is a decrease, 2 points if it is the same with the opposite foot). The time it takes to block to 0 point is the sensory blockade onset time.
Time frame: within 30 minutes from the popliteal sciatic block
Motor block onset time
Check for motor blockade every 5 minutes until 30 minutes after block performed. Dorsiflexion and plantar flexion is evaluated, compared to the opposite foot, on a 3-point scale (0 points for inability to move 1 point for reduced movement 2 points for normal movement). The time it takes to block to 0 point is the motor blockade onset time.
Time frame: within 30 minutes from the popliteal sciatic block
Block duration
Block duration is the time from when block is performed until the patient first complained of pain at the surgical site post-operatively.
Time frame: within 24 hours post-operatively
Time to first rescue analgesia
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Increase ropivacaine concentration by 0.05% from the concentration used in the previous participant.
Time to first rescue analgesia is the time from when block is performed until the patient first requested of rescue analgesics post-operatively.
Time frame: within 24 hours post-operatively
Any adverse events
Unintentional nerve damage that occurs during nerve block, pain, bleeding, infection, hypoxia, hypotension
Time frame: within 24 hours post-operatively