Study of Different Concentrations of Epidural Bupivacaine for the Effects on Vasodilatation and Sensory Block
This study aims to compare human subjects receiving epidural bupivacaine local anesthetic at different doses and concentrations and to assess the effect on vasodilatation (sympathectomy), sensory and motor block.
The hypothesis is that the drug concentration is more important than drug dose in the determination of the extent and intensity of differential sympathetic, sensory and motor block following epidural local anesthetic.
Drug: Epidural bupivacaine (dose/concentration/volume ranging)
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacodynamics Study
Intervention Model: Parallel Assignment
Primary Purpose: Prevention
|Official Title:||Sympathectomy-Mediated Vasodilatation and Differential Sensory Block After Epidural Bupivacaine: a Randomized Concentration Ranging Study|
- Index of sympathectomy: photoplethysmography derived amplitude-baseline ratio from foot and hand; data measured at time 0, 5, 10 and 20 min following epidural; data expressed as % change from baseline and as area under time effect curve.
- 1. Other indices of sympathectomy:
- a. Photoplethysmography derived baseline change (ln (Blepi/Blo));
- b. Photoplethysmography derived time lag between pulse reaching hand and foot;
- c. Blood pressure (mean, systolic, diastolic);
- d. Skin temperature changes (finger and toe temperature change from baseline, toe-thigh and finger-arm temperature gradients).
- 2. Sensory level (pinprick, touch, cold)
- 3. Motor block (Bromage scale)
- All assessments made at 0, 5, 10 and 20 minutes after epidural drug administration.
|Study Start Date:||March 1999|
|Estimated Study Completion Date:||September 1999|
There is controversy regarding the factors that determine the extent and intensity of epidural drug action. Most studies have focused on the inter-related triad of dose, concentration and volume.
We compare three groups: group A: 10ml of 0.5% bupivacaine; group B: 10ml of 0.25% bupivacaine and group C: 40ml of 0.0625% bupivacaine. When comparing these groups, groups A & B have the same volume of epidural drug, and groups B & C have the same total dose.
In particular this study compares different methods of assessing the sympathetic block (causing vasodilatation). These methods include skin temperature changes, hemodynamic changes and photoplethysmography.
|Hadassah Hebrew University Medical Center|
|Jerusalem, Israel, 91120|
|Principal Investigator:||Yehuda Ginosar, BSc MBBS||Hadassah Medical Organization|