Local Anaesthesia :
Q1. Define local anesthesia.
Ans. If has been defined as a loss of sensation in a circumscribed area of the body caused by depression of excitation in nerve endings or an inhibition of the conduction process in peripheral nerves.
Q2. Enumerate various methods of inducing local anesthesia.
Ans.
- Mechanical trauma.
- Low temperature.
- Anoxia.
- Chemical irritants.
- Neurolytic agents such as alcohol & phenol.
- Chemical agents such as local anesthesia.
Q3. What are the ideal properties of local anesthetic solutions?
Ans.
- It should be non irritating to the tissue when applied.
- It should not cause any permanent alteration of nerve structure.
- Its systemic toxicity should be low.
- The time of onset should be as short as possible.
- The duration of action must be long enough to permit the completion of the procedure yet not so long as to require an extended recovery.
Q4. What are the types of pain?
Ans.
- Pricking pain (lancinating pain):
- Pain arising from skin, mucous membrane, dental pulp and glands.
- Burning pain:
- Pain of longer duration mediated through unmyelinated nerves.
- Aching pain:
- Pain arising from muscles, Fascia, tendons. Ligaments, joints, bone, etc. usually of long duration and associated with referred pain.
Q5. Define saltatory conduction.
Ans. In myelinated nerves, jumping of current from node to node occurs because of the heavy insulation of the inter nodal areas of the axons which takes place. This type of conduction is known as saltatory conduction.
Q6. How does a local anesthetic molecule?
Ans.
- Altering the basic resting potential of nerve membrane.
- Altering the threshold potential.
- Decreasing the rate of depolarization.
- Prolonging the rate of repolarization.
Q7. What are the various theories of LA?
Ans.
- Acetyl choline theory.
- Calcium displacement theory.
- Surface charge theory.
- Membrane expansion theory.
- Specific receptor theory.
Q8. Define Pain.
Ans. Pain is defined as specific sensory experience to noxious stimuli mediated through nerve structures which are separated from those which mediate other sensations like touch or pressure.
Q9. Enumerate various theories of pain.
Ans.
- Specificity theory of pain.
- Pattern theory of pain.
- Gate control theory of pain.
Q10. What are the various types of nerve fibers?
Ans.
A α 12-22 microns.
A β 8-13 microns.
A γ 4-8 microns
A s 1-4 microns.
B 1-3 microns.
C 0.2-1.3 microns.
Q11. What are the advantage of vasoconstrictor?
Ans.
- Vasoconstrictor helps by slowing down the rate of absorption of local anesthetic.
- If increases the depth and duration of anesthesia.
- Vasoconstrictor reduces the bleeding in the surgical field by improving the vicinity of the operating field.
Q12. How do you classify local anesthetics?
Ans. A Esters:
- Esters of Benzoic acid.
- Esters of Para amino benzoic acid.
- Amides.
- Quinoline.
Q13. What is Felypressin?
Ans. It is a synthetic analogue of vasopressin (anti diuretic hormone). It is a non-sympathomimetics amine, categorized as a vasoconstrictor. Max dose 0.03 IU/ml
Q14. How many milligram of local anesthetic molecule is present in 1:10,000 concentration of vasoconstrictor?
Ans. 0.01mg/ml
Q15. Mention the local anaesthetic which has a longer duration action.
Ans. Bupivacaine
Q16. What is EMLA ?
Ans. EMLA is Eutectic Mixture of Local Anesthetic cream which consist of 2.5% lidocaine and 2.5% prilocaine.
Q17. How many milligram of local anaesthetic molecule is present in 1:80,000 concentration of adrenaline?
Ans. 0.0125 mg.
Q18. How many milligram of local anaesthetic molecule is present in 2% lidocaine?
Ans. 20 mg.
Q19. What is the maximum recommended dose of local anesthetic molecule for an adult 70 mg/kg body weight with adrenaline?
Ans. 4.4 mg kg/body weight
Q20. What is the maximum recommended dose of local anesthetic molecule for and adult 70 mg kg body weight without adrenaline?
Ans. 7.4 mg kg/body weight.