How much anesthetic is in a carpule?

Seems like an easy question right?
The glass carpule or cartridge is designed for 2cc of liquid local anesthetic right?
Makes all the calculations easy right?
WRONG!
First off, nobody thought of the rubber stopper when the glass cartridge was designed, and nobody ever bothered to change it. The rubber stopper takes up .2cc of volume, so there is 1.8cc available for the medication, right?
WELL MAYBE...
We all assumed for years that there was 1.8 cc of local anesthetic in each carpule. Then along comes articaine, which is finally ready to take on the FDA for use in the United States.
Nobody could prove that the carpule consistantly had 1.8cc of medication, once under the scrutiny of the FDA. They could prove there was 1.7cc all the time, but not always 1.8cc.
Articaine got labeled "1.7cc" or "at least 1.7cc" depending on the company you buy it from. Go ahead and check it out. Other companies soon followed for packaging of lidocaine and carbocaine.
What does this mean to us?
The change in numbers is very small, and if we practice safely, dosing patients really does not change, but the numbers are ridiculous!
Why didnt anyone ever remember the rubber stopper? Things would have been so much easier!
Except that we would then have to buy bigger syringes....

Is Septocaine (Articaine) safe for block anesthesia?

Lots of people have asked me this. There have been reports of parathesia or even anesthesia after the administration of articaine for an inferior alveolar block. Possible reasons include the high concentration (4%) or increased tissue penetration.

Parethesia or anesthesia can occur after a block with any anesthetic preparation. Reasons include:

• Direct needle injury;
• Direct injury to the blood supply or the nerve;
• Swelling or bleeding around the nerve which causes compression.

Having said that, reports of anesthesia/parathesia appear to be higher with Articiane.

I personally use Articaine for infiltration only. I have no problem with "hitting" my blocks using Lidocaine or Carbocaine, and Articaine's improved penetration is most needed when I infiltrate. Articaine can be invaluable in certain situations such as:

• Obtaining palatal anesthesia wirhout a palatal injection (especially in kids);
• Penetrating an area of inflammation or infection
• Need for less needle insertions when infiltrating large areas of the mouth.

What do you think?

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