This document discusses regional anesthesia techniques. It begins by explaining nerve physiology and conduction. It then classifies regional anesthesia based on the site of local anesthetic application, including topical, infiltration, field block, and intravenous regional anesthesia. The document describes various peripheral nerve blocks such as interscalene brachial plexus block, ankle block, and dorsal penile block. It also discusses central (neuroaxial) blocks like spinal anesthesia, epidural anesthesia, and caudal anesthesia, explaining their indications, techniques, effects, advantages, and disadvantages.

1. Regional Anesthesia

2. PHYSIOLOGY OF NERVE CONDUCTION
 Nerve Fiber – impulse – transmitting unit
 Membrane
 90% of lipids
 10% protein
 Channels guarded by “gates”
 K+ pass freely in and out
 Na+ barred outside
 Negative resting potential -70 to -90 mV

3. PHYSIOLOGY OF NERVE CONDUCTION
 Nerve Stimulation
 Gates open
 Na+ rushing in
 Shifting of polarity
 Depolarization

4. I. TOPICAL – skin or mucous membrane
spray – refrigeration (e.g. boils / abcess)
ointment – insect bites
instillation – urethral meatus
contact – cotton pledgets in nasal mucosa
II. INFILTRATION – incision site / tissue to be cut
(e.g. sebaceous cyst)
III. FIELD BLOCK – around tissue to be cut (e.g.
breast mass)
Classification of
Regional Anesthesia
(according to SITE of application)

5. IV. INTRAVENOUS REGIONAL (Bier Block)
Peripheral vein of
upper / lower extremity
I.V. catheter inserted
Desanguinated
extremity
Esmarch elastic
bandage

6. 2 tourniquets (BP cuffs)
bandage removed
LA injected over 2-3
minutes
Distal tourniquet inflated
after 20-30 minutes
Proximal tourniquet
deflated
Slow release of
tourniquet after at least 15-
20 minutes
Use: short surgical
procedure
< 45 minutes in upper /
lower extremity

7. V. CONDUCTION BLOCK – along nerve
or course of nerves
A. Peripheral Nerve Blocks
B. Central Blocks

8. Peripheral Nerve Blocks
RETROBULBAR NERVE
BLOCK (ciliary
ganglion)
 Indications
 Cataract surgery
 Corneal transplant
 Enucleation
 Complications
 Retrobulbar hemorrhage
 Globe perforation
 Contraindications
 Bleeding disorders
 Extreme myopia
 Open-eye injury

10. GASSERIAN GANGLION BLOCK
Branches of trigeminal nerve
(ophthalmic, maxillary, mandibular)
Indications
 Trigeminal neuralgia
 Cancer pain in face
 Operations in face teeth, gum, mandible, etc.
 Technique: LA injected into respective
foramen of nerve branches
Peripheral Nerve Blocks

12. CERVICAL PLEXUS BLOCK
 Anterior rami of C1-C4 spinal nerve roots
 Sensory supply to jaw, a neck, occiput, chest-
shoulders, clavicle, upper border of scapula
 Indications
 Operations in the neck
 Cervical lymph node biopsy
 Carotid endarterectomy
 Thyroid operations
Peripheral Nerve Blocks

15. BRACHIAL PLEXUS BLOCK
 Anterior rami of C4-T2 spinal nerve roots
 Entire motor supply of upper extremity
 Almost entire sensory supply – except over
shoulder and medial arm
Peripheral Nerve Blocks

16. Major Peripheral Branches
a. Axillary N – shoulder
abduction
b. Musculocutaneous –
elbow flexion
c. Radial – elbow, wrist,
and finger extensions
d. Median – wrist and
finger flexion
e. Ulnar – wrist and
finger flexion

17. BRACHIAL PLEXUS BLOCK
 Indication: operations of upper
extremity
 Approaches to Brachial Plexus Block
1. interscalene approach
2. Supraclavicular
3. Infraclavicular
4. axillary
Peripheral Nerve Blocks

18. Interscalene approach
BRACHIAL PLEXUS BLOCK

19. Axillary approach
BRACHIAL PLEXUS BLOCK

20. INTERCOSTAL NERVE BLOCK
 Anterior rami of 1st eleven spinal nerves
 At inferior surface of ribs
 Indications
 Post-op analgesia of thoracic and upper abdomen
surgeries
 Relief of pain from rib fractures, herpes zoster,
pleurisy
 Complications: pneumothorax
Peripheral Nerve Blocks

21. INTERCOSTAL NERVE BLOCK

22. INTERCOSTAL NERVE BLOCK

23. INTERCOSTAL NERVE BLOCK

24. Peripheral Nerve Blocks
WRIST BLOCK
 Ulnar nerve
 Median
 Radial
 Indications:
 surgery or analgesia distal
to metacarpophalangeal
joints
 suture of lacerations
 paronychia, abcess

25.  Digital branches of
ulnar, median, radial
 Indications:
 minor procedure in fingers
 Reminder:
 avoid using large volume
of LA
 do not add
vasoconstrictors
Peripheral Nerve Blocks
DIGITAL NERVE BLOCK

26. Proximal nerve blocks on lower
extremity
 Femoral nerve block
 Sciatic nerve block
 Obturatory nerve block
 Lateral cutaneous femoral nerve block
 Lumbar plexus
 Lumbar paravertebral block
 Psoas compartment block

27. ANKLE BLOCK
 Blocks five nerves supplying foot
a. Deep peroneal
b. Superficial peroneal
c. Saphenous
d. Posterior tibial
e. Sural
 Indications
 Surgery of foot and toes in frail patients who cannot
tolerate hemodynamic effects of GA or neuraxial
block
Distal Nerve Blocks on the leg

28. Distal Nerve Blocks on the leg
ANKLE BLOCK
 Precaution
 Avoid epinephrine to
reduce risk of
ischemia
 Complication
 Intravascular
injection

30. Peripheral Nerve Blocks
PUDENDAL NERVE
BLOCK
 sacral plexus (S2 – S3 –
S4)
 Indications
 perineal surgery
o hemorrhoids
o lacerations
 obstetric vaginal delivery
 Complications
 puncture of fetal head
 inadvertent IV infection

31. DORSAL PENILE BLOCK
 Base of penis at symphysis pubis
 Blocks dorsal nerve
 Fan-shaped injection at the base blocks dorsal and
ventral branches
 Indications
 Penile surgery
 Post-op pain relief
Peripheral Nerve Blocks

32. DORSAL PENILE BLOCK
 Precautions
 Avoid big volume of solution
 Avoid epinephrine or any vasoconstrictor
 Complication
 Artery spasm – ischemic injury to penis
Peripheral Nerve Blocks

33. Central Blocks = Neuroaxial
anesthesia
A. SPINAL ANESTHESIA
Sub Arachnoid Block, Intrathecal Block
 Local anesthestic deposited at subarachnoid
space
 Acts on spinal nerve roots, dorsal ganglia, not
on substance of spinal cord
 Redistributed via vascular absorption
 Produces sympathetic block, sensory analgesia
and motor block

34. Indications
 Surgery involving lower half of body
 Upper abdomen
 Lower abdomen
 Perineum
 Lower Extremity
 Obstetrics – vaginal delivery
Caesarian section
 Painful diagnostic and therapeutic procedures
below diaphragm

35. Contraindications
 Absolute
 Bleeding disorders
 Septicemia
 Inc. intracranial pressure
 Chronic dermatitis or infection near puncture site
 Pre-existing spinal cord disease
 Hypotension
 Patient refusal
 Systemic disease with neurologic sequelae
 Relative
 Hemorrhage
 Back problem due to muscle strain, arthritis
 Extremely tense / psychotics
 Respiratory disease

36. Drugs Used
 Tetracaine
 Lidocaine
 Bupivacaine
Factors Determining Level of Anesthesia
 volume of solution
 concentration
 barbotage
 speed of injection
 patient position
 specific gravity of solution
 site of injection
 height of patient
 increased intra-abdominal pressure

37. Technique
A. Position
 Lateral decubitus – knees flexed to chest
hin put down on chest (nose-to-knee)
 Sitting – when lateral approach is difficult (e.g.
obese patients)
B. Puncture Sites
 Interspaces between L2-L3, L3-:4, L4-L5
 Line joining highest points of iliac crests
crosses either body of L4 or interspace
between L3-L4

39. Structures Traversed By Spinal Needle
a. Skin
b. Subcutaneous Tissue
c. Supraspinous ligament
d. Interspinuous ligament
e. ligamentum flavum
f. Dura

40. PHYSIOLOGIC EFFECTS (Immediate Complications)
A. Cardiovascular
Sympathectomy  vasodilation   BP,  CR
B. Respiratory
Difficulty of breathing
Apnea (high level)
C. Gastrointestinal
Nausea / vomiting in 20%
DELAYED COMPLICATIONS
 Headache – leak of CSF
 Backache
 Urinary retention
 Paraplegia – hematoma

41. Levels of Spinal Anesthesia – Dermatomes Involved
1. Saddle Block – sensory loss involves lowers lumbar
and sacral segments.
Area that “sits on the saddle”.
2. Low Spinal – level of umbilicus (T10) lower
thoracic lumbars and sacrals.
3. Mid-Spinal – costal margin (T6) lower thoracic
lumbars and sacrals
4. High Spinal – nipple line (T4) thoracic segments
(T4 – T12) lumbars and sacrals

42. B. EPIDURAL ANESTHESIA
 Anatomy
 Epidural space – base of skull (foramen magnum) to the coccyx
(sacrococcygeal membrane)
 Distance from skin to epidural space – 4-5 cm
 Epidural space contains loose areolar tissue, fat, arterial and
venous networks, lymphatics, spinal nerve roots
 LA deposited in epidural space
 Block spinal nerve roots that traverse peridural space
 Blocks sympathetic nerves traveling with the anterior roots
 Applications range from sensory analgesia, minimal motor block, or
dense anesthesia and full motor block – controlled by drug choice,
concentration, dosage
Central Blocks

43. Types – selective blockade possible
because it can be performed at any
level of spine
 Cervical epidural
 Thoracic epidural
 Lumbar epidural
 Caudal epidural
Factors Influencing Spread of Solution
 Height of patient
 Drugs used
 Volume
 Concentration
 Level of puncture and catheter insertion

44. Technique
 Method
 Single dose injection
 Fractional – continuous epidural – repeated injections
of LA through catheter inserted into epidural space
 Position
 Cervical epidural – sitting (C7)
 Thoracic epidural (T7)
 Lumbar epidural
(L1-L2, L2-L3, L3-L4, L4-L5)
Lateral
Decubitus, full
flexion

47. Method of Identifying Epidural Space
Principle: negative pressure in space
 Loss of resistance
 Plunger of syringe pushed without resistance once
epidural needle is in
 Hanging Drop
 Drop of saline at hub of epidural needle is sucked in
once it enters space

49. Indications
 All operations below diaphragm
 May be used in
 Poor risk patients
 Cardiac diseases
 Pulmonary diseases
 Metabolic disturbances
 When GA is contraindicated
 When spinal anesthesia is contraindicated
 Painful conditions including post-op pain relief

50. Contraindications – similar to spinal
 Severe hemorrhage
 Coagulation defects
 Previous laminectomy
 Uncooperative / apprehensive
 Local inflammation at site
 Patient refusal
Advantages
 Well-defined area of anesthesia
 Longer duration
 More severe disturbances of spinal anesthesia minimized
 GI complaints minimized
 Catheterization minimized
 Less respiratory effects

51. Disadvantages
 Technically more difficult
 Muscle relaxation not complete
 Large volume necessary
 Danger of dural puncture
 Incomplete / patchy block
Physiologic Effects
 Similar to those observed in spinal anesthesia
 Slower onset
 Less intensity of motor and sensory block
Drugs: low-dose LA, opiods

52. C. CAUDAL ANESTHESIA
 LA injected into the epidural space in the sacral
canal through sacral hiatus
 Blocks lumbosacral plexus (T12, L1-5, S1-3) and
coccygeal plexus (S4-5, coccygeal nerves)
 Indications
 OB – vaginal deliveries
 Surgery involving lower abdomen, perineum
 Post-op pain control following these surgeries
especially pediatric patients
Central Blocks

53. Technique
 Patient prone or lateral
 Needle inserted into sacral hiatus
 15-20 ml Lidocaine
Physiologic Effects
 Similar to lumbar epidural
 Related to level achieved – volume of drug

56. Complications
 Accidental Dural puncture
 General systemic reactions
 Infection at site of injection
Disadvantages
 Difficult to obtain high level
 Needs big amount – systemic reactions possible
 Infection possible
 5-10% failure – anatomic anomalies or incorrect
method

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