Effect of Age on the Median Effective Dose(ED50) for Motor Block With Intrathecal Ropivacaine

Study Overview
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Brief Summary
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The primary aim of this study was to determine the median effective dose (ED50) for motor block of intrathecally-administered ropivacaine in adults (20-80 years), and to assess the effect of age on ED50 required for motor block.

Detailed Description
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This study was performed in adult patients undergoing transurethral, urological or lower limb surgery under combined spinal and epidural anesthesia. Patients were stratified according to age: 20-30, 31-40, 41-50, 51-60, 61-70, and 71-80 years. The spinal component of the anesthetic was established by bolus administration of various up-and-down doses of 0.75% ropivacaine, determined by Dixon's method, with the first patient receiving 15 mg, and with testing intervals of 1.5 mg according to failure or success of the preceding patient's motor block. The degree of motor block after intrathecal administration of each dose was evaluated by the modified Bromage and Hip motor function score. The primary outcome was obtained by administration of the mean dosage that was determined from the midpoints of all independent pairs of patients involving a crossover from failure to success during 5 minutes after the spinal injection. The ED50 were estimated from the up-and-down sequences using the method of Dixon and Massey and logistic regression. Other endpoints were included on the basis of sensory block level, duration of motor blockade, hypotension, and vasopressor requirements.

Official Title
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Effect of Age on the Median Effective Dose(ED50) for Motor Block With Intrathecal Ropivacaine

Conditions
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Anesthesia

Intervention / Treatment
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* Other: age


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients who were undergoing transurethral, urological or lower limb surgery, primarily under the spinal anesthesia Exclusion Criteria: Patients with diabetes, obesity, neuromuscular diseases, bleeding diathesis, hypersensitivity to amide local anesthetics, lumbar vertebrae abnormality, chronic back pain, or who were pregnant

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| age<br>subjects stratified according to age: 20-30 years (Group 1), 31-40 years (Group 2), 41-50 years (Group 3), 51-60 years (Group 4), 61-70 years (Group 5), and 71-80 years (Group 6). | Other: age<br>* subjects stratified according to age: 20-30 years (Group 1), 31-40 years (Group 2), 41-50 years (Group 3), 51-60 years (Group 4), 61-70 years (Group 5), and 71-80 years (Group 6).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the dose of intrathecal ropivacaine |  | at 5-min after administered ropivacaine | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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intrathecal; ropivacaine; motor blockade; local anesthetics