| ||||||||||||||
|
|
|||||||||||||
Department of Anesthesiology; McGill University; Montreal; Quebec, Canada; de_tran{at}hotmail.com
To the Editor:
Despite our being able to visualize neurovascular structures, ultrasound-guided infraclavicular brachial plexus blockade yields a variable success rate (80%95%) (13). We may explain this variation by the fact that local anesthetic spreads differently around the axillary artery (to anesthetize the three cords of the brachial plexus), depending on its point of injection. For instance, injection between the axillary artery and vein may result in failure, whereas injection posterior to the axillary artery leads to an improved success rate (4).
We have found placement of the needle tip (and subsequent bolus of local anesthetic) posterior to the artery, so predictive of success that we no longer use neurostimulation. Instead, under ultrasonographic guidance, using previously described landmarks (4), we aim to place the needle tip posteriorly to the axillary artery as shown in Figure 1. Correct placement results in a "double bubble" sign after local anesthetic injection. The inferior "bubble" is the local anesthetic solution and the superior "bubble" is the axillary artery (in short axis). Whenever a "double bubble" sign appears, our personal experience suggests that the success rate of infraclavicular blockade is almost 100%.
|
REFERENCES
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|