A Dose-Ranging Study of 0.5% Bupivacaine or Ropivacaine on the Success and Duration of the Ultrasound-Guided, Nerve-Stimulator–Assisted Sciatic Nerve Block

Abstract

Injecting 10 mL of 0.5% bupivacaine or ropivacaine below the CIEL produces comparable onset and duration of sensory and motor blockade as volumes as large as 30 mL.

Local Anesthetic Injection Speed and Common Peroneal Nerve Block Duration

“…6,17 Previous RCTs concur with this notion. [18][19][20] Thus, we assumed that 4.0 mL would give a more volatile nerve block duration and increase the likelihood of discovering a potential effect of LA injection speed, while providing an adequate and quantifiable nerve block.…”

“…Durations were median [range]: 11 [6][7][8][9][10][11][12][13][14], 12 [9-14], 10.5 [2-15], 11 [8][9][10][11][12][13][14][15][16][17], and 12 [9-18] hours, respectively (P = 0.294). In addition, we found no differences in secondary outcomes.…”

“…5 On the other hand, a too small volume of LA could fail to provide the desired effects. 6,7 Research has focused on investigating the influence of LA volume, concentration and dose on nerve block characteristics without compromising desired effects and aggravating safety. [7][8][9] Injection pressure affects the contact between deposited LA molecules and targeted nerve fibers.…”

Peripheral nerve block and local anaesthetic dose, how much is enough?

“…Some authors have reported longer-lasting sensory and motor block when using higher doses of local anaesthetic, and suggest that the additional analgesia provided by the sensory block warrants the use of higher local anaesthetic doses [24,25]. Other studies find no meaningful difference in block characteristics [26,27]. The key consideration in selecting an appropriate dose of local anaesthetic is achieving successful anaesthesia while minimising the likelihood of adverse patient outcomes.…”

“…The interrelationship between injectate volume, local anaesthetic concentration and the duration of conduction block has been studied with conflicting results [24][25][26][27]. It is intuitive that there may be a direct relationship between the success and duration of a block and the total local anaesthetic dose.…”