TY - JOUR

T1 - Volume of ropivacaine 0.2% and common peroneal nerve block duration

T2 - a randomised, double-blind cohort trial in healthy volunteers

AU - Christiansen, C B

AU - Madsen, M H

AU - Rothe, C

AU - Andreasen, A M

AU - Lundstrøm, L H

AU - Lange, K H W

N1 - © 2018 Association of Anaesthetists.

PY - 2018

Y1 - 2018

N2 - The volume-duration relationship using low concentrations of ropivacaine for peripheral nerve blocks is unknown, even though low concentrations of ropivacaine are increasingly used clinically. We investigated the effect of ropivacaine 0.2% on common peroneal nerve block duration. With ethical committee approval, 60 consenting, healthy volunteers were randomly allocated to receive one of five volumes of ropivacaine 0.2% (2.5, 5.0, 10, 15 or 20 ml) administered by ultrasound-guided, catheter-based injection (at 10 ml.min-1 ) near the common peroneal nerve. Our primary outcome was duration of sensory block, defined by insensitivity to a cold stimulus. Our secondary outcome was duration of motor block. Outcomes were assessed every hour from onset of block to complete remission. Intergroup differences were tested using one-way ANOVA followed by regression analyses using the 20 ml intervention group as reference. Block durations varied significantly (p < 0.0001) between groups. Mean (SD) sensory block durations were 9.2 (3.3), 12.5 (3.0), 15.5 (4.4), 17.3 (3.5) and 17.3 (4.6) h. Mean (SD) motor block durations were 3.3 (2.1), 7.2 (2.5), 9.2 (2.2), 12.7 (2.5) and 12.5 (2.5) h. Regression analysis showed that the effect of volume on block duration was progressively smaller with increasing volume, reaching a threshold volume above which there was no effect on nerve block duration (10 ml for sensory block and 15 ml for motor block). We conclude that there is a ceiling effect of increasing volume of ropivacaine 0.2% on both sensory and motor block duration of the common peroneal nerve.

AB - The volume-duration relationship using low concentrations of ropivacaine for peripheral nerve blocks is unknown, even though low concentrations of ropivacaine are increasingly used clinically. We investigated the effect of ropivacaine 0.2% on common peroneal nerve block duration. With ethical committee approval, 60 consenting, healthy volunteers were randomly allocated to receive one of five volumes of ropivacaine 0.2% (2.5, 5.0, 10, 15 or 20 ml) administered by ultrasound-guided, catheter-based injection (at 10 ml.min-1 ) near the common peroneal nerve. Our primary outcome was duration of sensory block, defined by insensitivity to a cold stimulus. Our secondary outcome was duration of motor block. Outcomes were assessed every hour from onset of block to complete remission. Intergroup differences were tested using one-way ANOVA followed by regression analyses using the 20 ml intervention group as reference. Block durations varied significantly (p < 0.0001) between groups. Mean (SD) sensory block durations were 9.2 (3.3), 12.5 (3.0), 15.5 (4.4), 17.3 (3.5) and 17.3 (4.6) h. Mean (SD) motor block durations were 3.3 (2.1), 7.2 (2.5), 9.2 (2.2), 12.7 (2.5) and 12.5 (2.5) h. Regression analysis showed that the effect of volume on block duration was progressively smaller with increasing volume, reaching a threshold volume above which there was no effect on nerve block duration (10 ml for sensory block and 15 ml for motor block). We conclude that there is a ceiling effect of increasing volume of ropivacaine 0.2% on both sensory and motor block duration of the common peroneal nerve.

KW - Adult

KW - Anesthetics, Local/administration & dosage

KW - Dose-Response Relationship, Drug

KW - Double-Blind Method

KW - Female

KW - Humans

KW - Male

KW - Nerve Block/methods

KW - Peroneal Nerve/diagnostic imaging

KW - Reference Values

KW - Ropivacaine/administration & dosage

KW - Time Factors

KW - Ultrasonography, Interventional

KW - Young Adult

U2 - 10.1111/anae.14400

DO - 10.1111/anae.14400

M3 - Journal article

C2 - 30184254

VL - 73

SP - 1361

EP - 1367

JO - Anaesthesia

JF - Anaesthesia

SN - 0003-2409

IS - 11

ER -