Abstract:Dose-finding studies enable the successful conduct of peripheral nerve blocks by ensuring the administration of appropriate doses of local anesthetic. However, the optimal dose-finding methodology remains ambiguous. In this research methodology article, we set out to review the basic aspects pertaining to dose-response curves (graded vs quantal), the pharmacodynamic indices required by dose-finding studies, the properties of different dose-finding methods (sigmoidal dose-response curve analysis, Dixon-Mood met… Show more
“…Volume assignment was carried out using a BCD up-and-down sequential method, where the total volume administered to each patient depended on the response of the previous one. 4,7,8 The first subject recruited received 20 mL. This initial volume was derived from the initial recommendation of Karmakar et al 1,3 Subsequently, volume assignment was based on the response of the previous patient.…”
Section: Discussionmentioning
confidence: 99%
“…Biased coin design constitutes a relatively new method to approximate the MEV for US-guided peripheral nerve blocks. 5,8 To date, most dose-finding studies have focused exclusively on MEV50 and relied on the Dixon and Massey up-and-down sequential method. 7 Maximum likelihood logistic or probit regression is then used to extrapolate to higher quantiles (eg, MEV95).…”
Section: Discussionmentioning
confidence: 99%
“…Unfortunately, such extrapolation can be notoriously imprecise. 8 In contrast, BCD allows the direct investigation of MEV at any quantile. 8 In the costoclavicular space, the 3 cords of the brachial plexus are situated closer together than in the lateral infraclavicular fossa, where the paracoracoid ICB is commonly performed.…”
For ultrasound-guided costoclavicular block, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 34 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and multiple-injection techniques.
“…Volume assignment was carried out using a BCD up-and-down sequential method, where the total volume administered to each patient depended on the response of the previous one. 4,7,8 The first subject recruited received 20 mL. This initial volume was derived from the initial recommendation of Karmakar et al 1,3 Subsequently, volume assignment was based on the response of the previous patient.…”
Section: Discussionmentioning
confidence: 99%
“…Biased coin design constitutes a relatively new method to approximate the MEV for US-guided peripheral nerve blocks. 5,8 To date, most dose-finding studies have focused exclusively on MEV50 and relied on the Dixon and Massey up-and-down sequential method. 7 Maximum likelihood logistic or probit regression is then used to extrapolate to higher quantiles (eg, MEV95).…”
Section: Discussionmentioning
confidence: 99%
“…Unfortunately, such extrapolation can be notoriously imprecise. 8 In contrast, BCD allows the direct investigation of MEV at any quantile. 8 In the costoclavicular space, the 3 cords of the brachial plexus are situated closer together than in the lateral infraclavicular fossa, where the paracoracoid ICB is commonly performed.…”
For ultrasound-guided costoclavicular block, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 34 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and multiple-injection techniques.
“…The use of ultrasound guidance has led to a reduction in recommended dose, and several studies have tried to establish the minimum effective doses for different PNBs. 17 However, exact individual dose requirements vary despite population estimates, 18 and our study suggests that there is a safety margin in the dose of local anesthetic tolerated by patients without developing major LAST after PNBs. Pharmacokinetics of absorption of local anesthetic after PNBs may also serve as a safety margin.…”
Section: Discussionmentioning
confidence: 82%
“…As noted, the ASA NACOR database analyzed nearly 1.5 million cases to determine the incidence and risk factors for perioperative cardiac arrest after a variety of cases, anesthetic techniques, and perioperative settings. 18 A similar accumulation of sufficient cases specifically pertaining to LAST after PNBs would be a formidable challenge. Alternatively, the rarity of cardiac arrest caused by LAST after PNBs may suggest that the evolution of the safety steps of our current practice for performing PNBs has reduced this once-feared bogeyman to a ghost.…”
Ropivacaine is a commonly used local anesthetic for brachial plexus blocks in children, but the minimum effective dose of ropivacaine for interscalene brachial plexus blocks has not been reported. The aim of this study was to determine the 90% minimum effective concentration (MEC90) of ropivacaine for an ultrasound‐guided interscalene brachial plexus block (ISB). A total of 155 patients, aged from 1 to 10 years, underwent unilateral surgical procedures on areas of the upper extremity not innervated by the ulnar nerve. The biased coin design up‐and‐down sequential method (BCD‐UMD) was used to determine the MEC90 of ropivacaine for ultrasound‐guided ISB. In our study, the initial concentration of ropivacaine was 0.07% in the toddler group and 0.09% in the preschool and school‐age groups. During the trial, the concentration of ropivacaine for each subsequent patient was determined by the blocking effect of the previous patient. In case of failure, the concentration for the next patient was increased by 0.01%. Otherwise, the concentration was either decreased by 0.01%, with a probability of 0.11, or kept the same, with a probability of 0.89. Overall, the MEC90 of ropivacaine was 0.104% (95% confidence interval (CI), 0.070%–0.106%) in the toddler group, 0.114% (95% CI, 0.090%–0.117%) in the preschool group, and 0.133% (95% CI, 0.099%–0.136%) in the school‐age group. No adverse events occurred. Our study showed that lower concentrations of ropivacaine could provide effective nerve blocks and reduce the risk of local anesthetics.
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