3. Definition
The term anaesthesia is derived from a Greek
word anaesthesis meaning no sensation.
Anaesthesia is the limited loss of feeling without
loss of consciousness. The anaesthesiologist
determine the method of administering the
anaesthesia and the decision is influenced by
the patient preference, age, physical status,
emotional status, co-existing disease, type,
length of the surgical procedure, post-operative
recovery from specific anaesthetic agent and
any requirement of the surgeon.
4. REGIONAL ANAESTHESIA
This is a type of anaesthesia that causes a
temporary loss of sensation in a particular
portion of the body(dermatone).
Usually it is used in patients whom general
anaesthesia is contraindicated. The choice
of regional agent depends on the type and
anticipated length of the procedure, patient
position during the procedure, and patient
physical and psychological status.
5. ADVANTAGES
It is simple
It is done at a reasonable cost
Easily induced
Minimal equipment required
Reduced post operative care
Fewer systemic body effects on body function
Decreased nausea and vomiting
Useful for a variety of patient in circumstances
where general anaesthesia is contraindicated
6. DISADVANTAGES
Lack of patient acceptance and fear of
being awake during the surgical
procedure.
Impracticality of anaesthetizing certain
areas of the body
Insufficient duration of anaesthesia.
Patient fear anaesthesia will wear off
prematurely
Rapid absorption leading to cardiac arrest
7. TYPES OF REGIONAL
ANAESTHESIA
(1)Spinal anaesthesia
Usually administered for surgical procedures
performed on the lower abdomen, inguinal
region, perineum and lower extremities.
POSITION
The patient lies on one side curled into fetal
position or sitting position and physician
inject local anaesthesia into cerebral
spinal fluid through subarachnoid space.
8. Cont…….
There is an immediate effect of anaesthesia on the
site of injection. The duration and level of spinal
anaesthesia are determined by:
-body weight
-site
-speed of injection
-specific gravity of anaesthetic agent
-position of patient immediately prior to injection
9. COMPLICATIONS
Headache-this result from cerebral spinal fluid leak from
the dual needle puncture leading to decreased pressure
within spinal cord and causes headache.
Backache
Hypotension
Paresthesias
Paralysis
Tinnitus
Arachnoiditis
Meningitis
Auditory and ocular disturbance
10. (2)Epidural anaesthesia
This is achieved by injecting local
anaesthesia agent through intervetebral
space into the surrounding of the dura
matter in spinal column. Anaesthesia may
be delivered at the thoracic, lumbar or
caudal level. It can be administered either
in a single dose or intermittently through
an epidural catheter and it diffuses slowly
into cerebral spinal fluid .Epinephrine may
be added to slow absorption.
11. INDICATIONS
Procedures on abdomen
Procedures on lower extremities
Treatment of chronic pain
Genital-urinary procedures.
In contrast to spinal anaesthesia, epidural
anesthesia requires high doses of local
anaesthetic, has slower onset and not
dependent on patient position for level of
anaesthesia
13. (3)NERVE BLOCK
This is achieved by the use of local anesthesia into
or around the nerve or a group of nerves that
innervates the operative site. Either continuous
or intermittent infusion may be used. For
example, intercoastal, auxiliary, digital blocks.
Nerve blocks interfere with sensory, motor or
sympathetic transmission. Onset and length of
the block depend on amount and concentration
of the anaesthetic agent. Also used in chronic
pain
15. (4)BIER BLOCK
It is achieved by administering local
anesthetic agent into the venous system of
an exsanguinated extremity.
A tourniquet is used to prevent the agent
from entering systemic circulation.
18. (5)FIELD BLOCK
This involves injecting anaesthetic solution
around the area to be anaesthetized. For
example, administering lignocaine when
inserting Norplant.
19. TOPICAL/SURFACE
ANAESTHESIA
This involves applying local anaesthetic to skin as
mucous membranes. Such application makes
sensory receptors unresponsive to pain, itching
and other stimuli.
They are usually ingredients of various ointment
solutions or lotions designed for use at particular
sites. For example, preparations available for
use on eyes, ears, nose, oral mucosa, perineum,
hemorrhoid and skin.
