Lower Limb Surgery
Conditions
Brief summary
This study aims to determine the minimum effective dose of bupivacaine 0.5% in 90% of patients undergoing lower limb surgery with ultrasound-guided spinal anesthesia using Taylor's approach. A biased coin design up-and-down sequential method is applied. The initial dose is 15 mg of bupivacaine 0.5%. After 45 successful spinal anesthesia, the ED90 of bupivacaine 0.5% will be calculated.
Detailed description
The minimum effective dose of local anesthetics for spinal anesthesia using Taylor's approach is not known. This study aims to determine the minimum effective dose of bupivacaine 0.5% using a biased coin design up-and-down sequential method. Patients will receive real-time ultrasound guided spinal anesthesia using Taylor's approach. The initial dose is chosen as 15 mg on the basis of clinical experience. Subsequently, if a patient has an inadequate block, the bupivacaine dose is increased by 2 mg in the next subject. If a patient has a successful block, the next subject is randomized to receive either a lower dose (with a decrement of 2 mg), with a probability of b = 0.11, or the same dose, with a probability of 1 - b = 0.89. Forty five successful blocks will be accomplished. MED90 will be calculated by isotonic regression.
Interventions
PROCEDUREspinal anesthesia
Patients will receive real-time ultrasound guided spinal anesthesia using Taylor's approach. Various doses of bupivacaine 0.5% (Bupivacaine hydrochloride injection, Harvest Pharmaceutical CO., LTD., Shanghai, China) will be administered.
Sponsors
Huazhong University of Science and Technology
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* American Society of Anesthesiologists physical statusⅠ- Ⅲ * Lower limb surgery, expected operation time within 2 hours
Exclusion criteria
* Patient refusal * American Society of Anesthesiologists physical status IV/V * Peripheral neuropathy * skin infection at the site of injection * allergy to bupivacaine or lidocaine * BMI \> 35 kg/m2 * coagulation disorders
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The minimum effective dose of bupivacaine in spinal anesthesia using Taylor's approach | up to 6 months | The minimum effective dose of bupivacaine in spinal anesthesia using Taylor's approach is based on 45 successful spinal anesthesia performed in patients undergoing lower limb surgery. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| the upper level of the sensory block 25 min after bupivacaine injection | 25 min | the upper level of the sensory block 25 min after bupivacaine injection |
| the incidence of hypotension | during anethesia and operation | the incidence of hypotension |
| the duration of sensory spinal anaesthesia for the lower extremity | up to 3 days postoperation | the duration of sensory spinal anaesthesia for the lower extremity |
| postoperative neurological complications | up to 3 months postoperation | postoperative neurological complications |
Countries
China
Outcome results
None listed