3. INTRODUCTION
Local anesthetic induced blockade
of peripheral nerve impulses from a
targeted body part with preserved
level of consciousness
Injecting local anesthetic near the
course of a named nerve
• Surgical procedures in the distribution of
the blocked nerve
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6. ADVANTAGES
Avoids general anaesthesia complications
• Safer than GA especially when anaesthetist is inexperienced
Pt remains awake .....pt will & helpfull for suegeon----
feedback
Postops analgesia----continue / catheter
Less PONV-----less opiods need
Less post ops sedation------less confision(cognitive functions)
in elderly
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7. Faster return to street fitness & early discharge
Cheep & relatively safe in remote location
hemodynamic stability than neuraxial & GA
Sole anesthetic technique , supplemented with monitored
anesthesia care (moderate sedation) or with a "light" general
anesthetic
Premptive analgesia
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8. Less immunosuppressive than GA
Excellent alternative to GA
• Hemodynamically compromised
• Too ill to tolerate GA
• MH
• PONV is risk
Growing populalarity of RA & PNB
• Modern equipments—USG,Nerve stimulator ect
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9. DISADVANTAGES
TIME DELAY
• 15-30 MIN –Procedure & onset
PATIENT FACTORS
• Discomfort due to procedure & positioning & awake during surgery
• Distress due to paralysis & numbness---postops
• Managed easily—benzodizepine & opiods
SURGEON FACTORS
• Irritated by awake & conversation with surgeon
ANAESTHETIST FACTORS
• Skill,knowledge & proper equipments
BLOCK FAILURE
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11. NERVE DEMAGE
• Chronic paresthesias
• Permanent N demage
FAILURE RATE-----10%
SURGERY OUTLASTS THE BLOCK
• If No catheter----GA
LOCAL ANAESTHETIC TOXICITY
SPECIFIC COMLPICATIONS RELATED TO NERVE BEING BLOCKED
• Respiratory failure-phrenic N Block
• Seizures ---intraarterial injecton
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14. Related to specific N Block
• Interscalene block
• with contralateral phrenic N paralysis
• Severe pulmonary disease
Increased risk fo LA toxicity
• Bilateral axillary Block
• Multiple intercostal blocks
LA Allergy
Ring block at site---endarteries---LA
containing Adrenaline
• Penile block,toes,fingers etc
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15. RELATIVE
COTRAINDICATIONS
Demented , combative & uncooperative patients
Pediatric patients
Placing block under GA
Surgeons who feel uncomfortable
Uncertain duration of surgery
Bloodstream infection
Preexisting peripheral neuropathy
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17. Haematoma
• Bleeding diorder
• Anticoagulant drugs
Wrong drug
Pneumothorax
• supra &infra clavicular
• inter costal block
Psychological reaction
• Vasovagal –mistaken as LA toxicity
• Anxious pt--sedate
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18. 1.LA TOXICITY
Immediate or delayed-----signs &
symptoms (CNS & CVS)
Prevention ---always
• Maintain IV line before
• Have resuscitation equipments & drugs
• Always aspirate before injecting
• Inject slowly & aspirate after every 3-5 ml
• Stablize needle ……short fine bone plasting tubing
b/w needle & synge (isolated needle technique)
• Observe pulse,ECG & sign of IV injection
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20. 2.NERVE DEMAGE
Direct by needle or by injection of LA
Eliciting paraesthesia technique -----can demage
• Withdraw 1-2 mm after eliciting paraesthesia-before
injection
Incidence---experienced anaesthetist
• 1 in 1000 blocks
• Most dysaesthesiasis & paresis resolve—few months
• 1 in 10000 blocks=permanent demage
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21. RECOMMENDATIONS TO REDUCE
RISK OF NERVE DEMAGE
Use short bevel needle
Use nerve stimulator & insulated short bevel needle
Avoid rapid,forceful injection
• STOP –undo resistance & severe pain-----withdraw
& then reinject
Avoid block under GA
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22. 4.VASOCONSTRICTOR
PROBLEM
General rule—epinephrine should not be used in
concentration > 1:200000 (5ug/ml) in PNB
• Skin ----- 1:300000 or 1:400000 sufficient
• Dentist –1:80000 but in small vol
Never use----areas of endarteries
Careful-----ischemic areas---varicose leg ulcer
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23. H/O IHD-----avoid/reduce dose---- can cause
palpatation,angina,HTN
Pregnancy-----epinephrine in significant
quntity -----avoid /reduce dose
Max recommended dose of epinephrine---
4 ug/kg
Epinephrine sol-----lower Ph--pain on
injection-----can be reduced by
• Adding sodium bicarbonate
• Felypressin in stead of epinephrine
• Warming the sol to body temp
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24. INFECTION
Aseptic technique
No needle prick through infected skin
except abscess
Use atiseptic Alcoholic
Betadine(povidone/ iodine in ethanol)
• 1% chlorhexidine in 75% alcohol—
allergic to iodine
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25. PREPARATION
FEW GOLDEN RULES
• Designed procedure room—block room
• Insert an intravenous lin e before
• Monitor (pulse oximetry,EG G , BP
• Practice proper aseptic technique .
• Resuscitation equipments at hand
• Patients informed consent
• Adequate knowledge of the correct
tehnique an d know how to handle
complications
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34. STIMULATION AND
INJECTION TECNIQUE
Initial current
2-3 mA
Frequency
1-2 Hz
Threshold current
0.3- 0.5 mA
Aspirate– inj LA 1-2
ml----no pain &
resistance
Aspiration test 5- 10
ml LA injected
slowly
Increase the current
to initial level
No stimulatory
response -inject the
remaining drug
Recurring response
- May indicate
intraneural needle
position
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36. UNIPOLAR B-BEVEL
NEEDLES
less-experienced
practitioners, the
shortest recommended
needle is generally
safest
longer needle (up to 5
cm) may also be
indicated in morbidly
obese or very muscular
patients.
approach and the
patient population--
e.g., adult vs. pediatric,
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25-150 mm
20-25G
47. Direct visualization of nerves & other
structures
Visualization of LA spread
Re-position of needle in case of
misdistribution of LA
Avoidance of side effect- due to
excess dose of LA
ADVANTAGES OF USG47
48. Avoidance of painful muscle
contractions due to PNS
Faster onset
Longer duration of blocks
Improved quality
Blocks under GA
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49. Short Axis (SAX) –
• probe is aligned perpendicular to the axis of the nerve, the
nerve is seen in cross section
Long Axis (LAX) –
• probe is aligned parallel to the axis of the nerve
Short Axis View is preferred due to easy identification of
nerves, more stable view & allows to visualise circumferential
spread of LA------ “Doughnut” sign
BASIC VIEWS ON USG49
50. Ultrasound scanned image obtained in the infragluteal fossa midway
between the greater trochanter and ischial tuberosity with the probe
oriented along the long axis of the sciatic nerve. The sciatic nerve is
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51. 51
Ultrasound scanned image of the femoral nerve surrounded by
Hypoechoic (dark) local anesthetic (L) creating a “doughnut” sign
Doughnut
sign
52. In plane (IP) – long axis of the needle is
oriented to the long axis of the probe
• Entire needle can be seen
Out of plane (OP) – the long axis of the
needle is the oriented perpendicular to
long axis of the probe
• Only part of the needle is seen
Contd…
NEEDLE APPROACHES52
55. 55
Schematic representation of the views and needle approaches for
nerve blocks with ultrasound imaging. A. Short axis view of a nerve
with an out-of-plane needle approach. B. Short axis view of a nerve
with an in-plane needle approach. C. Long axis view of a nerve with
an out-of-plane needle approach. D. Long axis view of a nerve with
an in-plane needle approach. Modified6.
56. 56
Picture showing the orientation of the ultrasound probe
and the needle for placement of an interscalene block with
the in-plane needle approach
VIEW
SHORT /
LONG ?
57. TECHNIQUES
Single injection
Multiple injections---axillary block
Using catheters
• Intermittent dose
• Continuous
Field block---superficial cervical plexus block
• Large vol of LA in general location of cutaneous N
• Minor/superficial surgery
• Supplement to PNB & Neuraxial blocks
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59. CHOICE OF LOCAL
ANAESTHETICS
Purpose of block
• Anaesthesia or analgesia
Onset
Duration of block
Site & area of block—vol
Degree of sensory Vs motor block
Maximum toxic dose
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61. CONCENTRATION
ANAESTHESTHETIC BLOCK
• 1.5-2% Plain Lignocaine----------max 3 mg / kg
• 1.5-2% Lignocaine with adrenaline--- 7mg / kg
• 0.5% Bupivacaine---------max 2 mg / kg
• Mepivacaine 2%
• o.75 % Ropivacaine-------max 2-3 mg / kg
ANALGESIC BLOCK
• 0.125% Bupivacaine, 0.2% Ropivacaine,
• Opiods, Clonidine.
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62. PNB PLACEMENT
TECHNIQUES
Anatomy
Loss of
resistance and
tactile feedback
Evoked
paresthesia
Nerve stimulator
(goal 0.2-0.5 mA)
Ultrasound
guided
Percutaneous
electrical
guidance
1
2
3
4
5
6
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OTHERS
1.Droppler
2.CT
3.MRI
LA-- in
Perineural
area
63. CONCLUSION
Not as a first case
Centralize your equipment
Select proper block
Good knowledge of anatomy
Know about potential complications on treatment
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64. Select right patient
Pick the right surgeon
Be confident about your block
But still if you fail--Failures are the
stepping stones for success
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65. QUESTION 1
Anaesthetist was performing a peripheral nerve
block with help of neve stimulator & ultrasound
……he introduces insulated short bevel 22G
needle at location…….& observe muscle
contractions in nerve related area at 0.3
mA(n=0.2-o.5 mA).after injecting 1ml of LA
muscle cotractions disappear.He injects rest of
10ml sol in incremental doses.Surgeon strat
surgery after5 minutes but Pt feels
pain……..Anaesthetist is quite sure about
block……WHY Pt. feels pain ??
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66. QUESTIOIN 2
Anaesthetist introduced linsulated long bevel
needle to block a peripheral nerve & observes
muscle contractions at 0.2 mA ……….while he
injected 1ml of LA ,……he had to stop the
injection due to severe pain………moreover
muscle contraction did not disappeared ..
• WHY SEVERE PAIN ON INJECTION…?
• WHY MUSCLE CONTRACTIONS DID NOT DISAPPEAR ON
INJECTING LA….?
• WHAT SHOULD BE THE ACTION OF ANAESTHETIST
NOW…?
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