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. Classification of Regional Anesthesia (according to SITE of application)
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)

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 minutes
Proximal tourniquet deflated
Slow release of tourniquet after at least 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. Peripheral Nerve Blocks
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

12. Peripheral Nerve Blocks
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

15. Peripheral Nerve Blocks
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

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

18. BRACHIAL PLEXUS BLOCK
Interscalene approach

19. BRACHIAL PLEXUS BLOCK
Axillary approach

20. Peripheral Nerve Blocks
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

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

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. Distal Nerve Blocks on the leg
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

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
hemorrhoids
lacerations
obstetric vaginal delivery
Complications
puncture of fetal head
inadvertent IV infection

31. Peripheral Nerve Blocks
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

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

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 Relative 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 Factors Determining Level of Anesthesia 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 Interspaces between L2-L3, L3-:4, L4-L5
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
Saddle Block – sensory loss involves lowers lumbar and sacral segments.
Area that “sits on the saddle”.
Low Spinal – level of umbilicus (T10) lower thoracic lumbars and sacrals.
Mid-Spinal – costal margin (T6) lower thoracic lumbars and sacrals
High Spinal – nipple line (T4) thoracic segments (T4 – T12) lumbars and sacrals

42. Central Blocks 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

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 Lateral Decubitus, full flexion Method Position
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. Drugs: low-dose LA, opiods
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. Central Blocks 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

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

57. THANK YOU