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

China Three Gorges University, Yichang, China

Status: Completed

Conditions: Anesthesia

Treatments: Other: age

Study type: Observational

Funder types: Other

Identifiers

NCT02102607

China Three Gorges University (Registry Identifier)

intrathecal ropivacaine

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 120 patients

Sex: All

Ages: 20 to 80 years old

Volunteers: No Healthy Volunteers

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

Trial design

120 participants in 1 patient group

age

Description:

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).

Treatment:

Other: age