Why is the rubber stopper in the carpule is indented inside the glass barrel & not just ending at it's end ?!
Question: Why is the rubber stopper in the carpule is indented inside the glass barrel & not just ending at it's end .?
our college professor asked us to search for the answer & i couldn't find itHealth Question & Answer
Answers:
If you look at the metal syringe, you will see it has a barb at the end. This is for locking into the rubber bung.
Why is this necessary.? Because when injecting local anaesthetic (LA), we are aiming to be as close to the nerve bundle as possible (especially with blocks). But also near the nerve bundles are veins and arteries. If you inject into a vein or artery, then:
1. the LA will be taken away thru the bloodstream and not encircle the nerve. Thus, poor anaesthesia.
2. the LA in the bloodstream will cause the patient to have a racing heart because of the adrenaline that usually accompanies the LA. Not pleasant for the patient.
Therefore, just before injecting, you should check to see if you have inserted the needle into a vein or artery. To do this, the barb is locked into the bung so that you can pull it backwards. If blood comes back into the cartridge, then you are in the bloodstream, and have to reposition the needle before injecting.Health Question & Answer
Why is this necessary.? Because when injecting local anaesthetic (LA), we are aiming to be as close to the nerve bundle as possible (especially with blocks). But also near the nerve bundles are veins and arteries. If you inject into a vein or artery, then:
1. the LA will be taken away thru the bloodstream and not encircle the nerve. Thus, poor anaesthesia.
2. the LA in the bloodstream will cause the patient to have a racing heart because of the adrenaline that usually accompanies the LA. Not pleasant for the patient.
Therefore, just before injecting, you should check to see if you have inserted the needle into a vein or artery. To do this, the barb is locked into the bung so that you can pull it backwards. If blood comes back into the cartridge, then you are in the bloodstream, and have to reposition the needle before injecting.Health Question & Answer
I think its so its easier to engage with the aspirating syringe. Health Question & Answer