The sooner practitioners incorporate regional anesthetic techniques into their practice, the sooner proficiency will be achieved. It has been stated that 50 regional procedures are required to develop proficiency. 1 However, this will obviously depend on previous experience, opportunities for training and access to supervision.
When starting ultrasound-guided regional anesthesia, it is imperative to practice scanning the relevant area before blocks are attempted. Accurate recognition of the relevant sonographic anatomy is essential. Once confidence with sonographic anatomy is acquired, blocks can be cautiously performed on patients. It is a good idea to use concomitant neurostimulation to confirm the relevant target structures. Sustained motor responses (e.g. at < 0.5 mA) are not required; just a brief motor response at 0.8-1.0 mA to confirm the target structure. Once further confidence is developed, concomitant neurostimulation can be abandoned if indicated.
For anesthesiologists experienced with nerve stimulation guided blocks, it is important to not significantly change a technique that is already effective, otherwise block success will initially fall. Similar to the approach described above for operators new to peripheral nerve blocks, first scan the relevant area to gain experience with sonoanatomy and then perform the block with the traditional nerve stimulation guided technique. Later, perform the block under real time ultrasound needle guidance, still aiming for a traditional needle endpoint (e.g. sustained motor responses at < 0.5 mA). Later still, use the nerve stimulator to confirm the sonographic anatomy by eliciting a brief motor response at 0.8-1.0 mA, but deposit the LA under real-time guidance. Ultimately, for some blocks, the nerve stimulator will not be required.
Practicing in-plane vs. out-of-plane needle alignment
The value of practicing the above needle alignment techniques before blocks are attempted on patients cannot be over-stressed. Purpose designed “phantoms” can be used for this purpose, or alternatively, a large turkey breast or similar flesh can be used. It is also a good idea to practice the steps described for perineural catheter placement before attempting on patients. See also in-plane vs out-of-plane discussion.
Avoiding wrong side or wrong site blocks
The only way to eliminate the risk of performing a wrong side block is to stop performing blocks period. Protocols can reduce risk, but studies have shown that protocols (no matter how drastic) only reduce, not eliminate risk. Factors thought to contribute to wrong side/site blocks include operating room patient turnover pressure and distraction. Lower limb blocks are thought to be associated with higher risk because the blocks are usually performed with the operator facing caudad to cephalad, and therefore the operator’s right vs. left are reversed compared to the patient’s right/left. A simple and effective way to significantly reduce wrong side/site block risk is to make a habit of always marking the block site with a surgical marking pen immediately before block placement. This simple practice gets the operator thinking of the correct side/site immediately before needle-skin penetration.
1. Kopacz DJ, Neal JM, Pollock JE. The regional anesthesia "learning curve". What is the minimum number of epidural and spinal blocks to reach consistency? Reg Anesth 1996;21:182-90.