This segment will feature a unique pearl learned by a junior VIR staff during residency or fellowship to share with our community. This pearl is written by Dr. Joel Woodley-Cook from Scarborough Health Network.


A Dr. Sniderman Nugget: How to Reduce Pain Associated with Local Anesthesia Injection 

It became clear early on in VIR fellowship that Dr. Sniderman had many passions in life. Two of these passions included teaching and patient care. He would literally sacrifice himself for both passions, whether it was during his Friday morning teaching rounds despite being in pain from a recent fractured hip or giving patients his personal mobile number and getting calls throughout the night regarding post-UFE pain management.

Dr. Sniderman bestowed many pearls upon his mentees, including the liberal use of roadmapping, vascular ultrasound tips, being careful (and typically avoiding altogether) of advancing a wire beyond a catheter*, and teaching the Subway sandwich artist to hollow out the bun to reduce carb intake. Dr. Sniderman was a strong advocate for patient safety and comfort, and although he taught numerous techniques and tricks, one stands out as it highlights his empathy, prioritizing patient comfort, and improving the patient experience.

The following technique was taught by Dr. Sniderman after he read a 5 Things To Know About CMAJ article on how to reduce the pain of local anesthesia injection [1].

Below is a summary of these tricks on how to reduce the pain of local anesthesia injection:

  1. Using a smaller diameter needle
    • Encourages slow injection thereby reducing pain from volume expansion.
  2. Warming the injection solution
    • At the beginning of the day, Dr. Sniderman would warm his vials for the day.
    • Resources vary, but a gel warmer, towel warmer, or warm water bath can be used.
  3. Buffering lidocaine with sodium bicarbonate
    • The burning sensation of lidocaine, an acid with a pH of 4.7, can be reduced with a 10:1 mix of 1% lidocaine:8.4% sodium bicarbonate.
    • Prior to warming, Dr. Sniderman would add 5 mL of sodium bicarbonate to the 50 mL bottle of 1% lidocaine (with or without epinephrine).
  4. The initial injection should be perpendicular to the skin
    • Injections performed at 90o intersect fewer dermal nerve endings, which tend to branch out.
  5. Pause after initial subdermal injection
    • The first injection should be a 0.2 – 0.5 mm subdermal injection, as opposed to intradermal, followed by a pause.
  6. Maintain visible anesthetic ahead of the advancing needle tip
    • This ensures anesthetizing downstream nerves prior to tip penetration.

*I recall Dr. Sniderman’s analogy of the tip of a wire acting like a sword, which should be “unsheathed” from the catheter to prevent dissection instead of sticking the vessel wall with the pointy bit.

Reference:

  1. Strazar R, Lalonde D. Minimizing injection pain in local anesthesia. CMAJ. 2012;184:2016.