Instruments used in LA

Question 1

Syringes

Answer 1

to which double ended needles are attached by means on a screw hub
they are metal barrel with a plunger attached to a spring loaded hinge mechanism at one end.

Question 2

Some syringes

Answer 2

allow aspiration before injection + allow the detection of the needle point in a blood vessel which avoids the risk of accidental intra-vascular injection + possible fainting

Question 3

Aspirating syringe

Answer 3

before administration of LA the operator pulls back slightly on the plunger + checks for blood ensures that the anaesthetic solution will not be deposited in a blood vessel (they have a harpoon rod)

Question 4

Self aspirating syringe

Answer 4

feature a blunt harpoon rod that allows syringe to aspirate by means of counter pressure, blood will be visible in cartridge if injected into a blood vessel

Question 5

Most cartridges will have:

Answer 5

anaesthetic agent + buffering agents to reduce acidity which reduces pain during administration

• preservatives to maintain stability of solutions
• fungicide to prevent proliferation of minute fungi
• reducing agent to present premature deterioration of the vasoconstrictor

Question 6

Needles

Answer 6

• hypodermic needles are classed as long or short,
• they have a central lumen + the choice of needle should allow penetration to depth required before its complete length has entered the tissue
• the end of needle which is used to puncture tissue is bevelled to aid easy penetration
• needles are colour coded, sealed, pre-sterilised + disposed of

Question 7

Long needles

Answer 7

used for ID blocks + are about 3.5cm in length + have a wider gauge

Question 8

Short needles

Answer 8

are roughly 2cm long + are of finer gauge