Monday, June 27, 2016
IV nerve block
I recently had arthroscopic surgery for torn rotator cuff. During the nerve block procedure some anesthetic got into a vein. Do I need to be concerned about any permanent damage or complications?
Thanks for your question.
You probably had a brachial plexus block. The brachial plexus is a grouping of nerves coming from the cervical (neck) portion of the spinal cord. These nerves can be blocked by injecting local anesthetic in the neck area, or above or below the clavicle (collar bone).
The injection has to be very precise to achieve the desired effect, and also to avoid injecting the anesthetic medication into the wrong structures. One of the structures in the neck to avoid injecting into is the vertebral artery. There are also veins. If anesthetic is unintentionally injected into a blood vessel, the consequences range from none to serious. Mild symptoms can occur (ringing in the ears, dizziness, numbness around the mouth, metallic taste) for a minute or two. If enough anesthetic gets into the blood stream however, especially if injected into the vertebral artery, seizures (convulsions) and unconsciousness can occur.
If seizures occur, these can be fairly easily managed with normal resuscitation measures and they stop within minutes as the anesthetic is processed by your body.
Finally, if enough anesthetic of a particular kind (such as the commonly used bupivacaine) gets in, heart disturbances, and even cardiac arrest can occur. This is very rare but of course very serious, and also much harder to treat successfully.
To avoid such rare but awful consequences a great deal of care is taken. Various methods are available to make sure the needle is in the right place (e.g. nerve stimulators, ultrasound) Before any significant amount of anesthetic is injected, the doctor will be draw back on the syringe (aspirate) to make sure there is no blood. A small amount of anesthetic may be administered initially and then there is a pause to ensure there are no problems.
Then the rest of the dose is administered slowly and carefully, making sure the position of the needle does not change.
If you're writing and asking me about this, you survived the injection of anesthetic into a vein. In this type of case there are usually no known long term problems of the kinds you mention.
Gareth S Kantor, MD
Assistant Professor of Anesthesiology
School of Medicine
Case Western Reserve University