Local Anesthesia: Science behind Local Anesthesia and It’s Types

The purpose of local anesthesia is the elimination of pain in a limited area by blockade of the nerve- endings and nerve trunks in the body part.local-anesthesia

Depending on the way of introduction of the anesthetizing preparation we distinguish the following types of local anesthesia:

1. Superficial anesthesia is reached by smearing of integuments and mucous membranes. Contact anesthesia is widely applied at interventions on respiratory tracts (bronchography, bronchoscopy) and at fiber gastroscopy. In these cases, anesthetic is applied.

2. Infiltration anesthesia is based on the treatment of tissues in the field of future operational access by the anesthetic solution. Most often as anesthetic 0.25 – 0.5% Novocain solutions is used.
Equipment – In the beginning Novocain is injected by a fine needle intradermally, thus this site of skin grows white, takes a form of “a lemon crust”. “The lemon crust” is framed throughout future dermal section. Then a solution of Novocain is injected by a thicker and longer needle into a hypodermic fat, then into a muscle and deep lying tissues.
Local infiltration layer-by-layer anesthesia or the method of “a creeping infiltrate” is a kind of infiltration anesthesia. The method is offered by A.V. Vishnevsky.

3. Conduction anesthesia – is based on discontinuing of conduction on a nerve trunk. More strong solutions of Novocain are used. Conduction anesthesia is used:

  • At ablation of a femur for anesthesia of the sciatic nerve.
  • In stomatology – For extraction of teeth.
  • At finger operations – We use the method of Oberst-Lukashevich

4. Endosteal anesthesia – It is applied at operations on extremities.

5. Local intravenous and intra-arterial anesthesia -It is used seldom, at operations on extremities.

6. Spinal anesthesia -It is a kind of conduction anesthesia when anesthetic solution is injected into a subarachnoid space of the spinal channel.
Spinal anesthesia is dangerous, complications are possible: injury of the spinal cord, collapse, at distribution of anesthetic up to the level of the fourth thoracic vertebra paralysis of intercostals muscles and diaphragms is possible that can lead to respiratory standstill.

7. Epidural anesthesia -It is a kind of conduction anesthesia.

8. Novocain blockade – At a series of diseases or injuries Novocain blockade must be used for good anesthesia. The effect of such blockade depends on the blockade of the nerve-endings and trunks, and also due to action of Novocain on regulatory processes of the central nervous system.

Dangers and complications of local anesthesia

  • Allergic reaction to anesthetic, up to anaphylactic shock.
  • Toxic effect of anesthetic at the preparation overdosage.
  • Collapse.
  • At the hit of anesthetics in vessels fast intoxication develops – paleness of integuments, cold sweat, falling of blood pressure, loss of consciousness, respiratory standstill.
  • Post-injection infiltrates and abscesses after Novocain blockade – at non-observance of rules of asepsis.

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