4. • Sedation – This is a continuum between normal consciousness and
general anesthesia.
• A medically controlled state of depressed consciousness that
allows patients to maintain:
• protective reflexes
• patent airway independently
• appropriate response to verbal and physical stimuli
5. LEVELS OF SEDATION
• There is seamless progression from minimal sedation to deep
sedation in which verbal contact and protective airway reflexes
may be lost.
• The levels of sedation;
- minimal sedation
- moderate sedation
- deep sedation
- general anesthesia
6. Minimal sedation
• It’s equivalent to anxiolysis which is a drug-induced relief of
apprehension with minimal effect on sensorium.
Moderate sedation
• Depression of consciousness in which patient can respond to
external stimuli (verbal or tactile).
• Conscious sedation.
7. Deep sedation
• Depression of consciousness in which patient can be aroused by
purposefully repeated or painful stimuli.
• May not be able to maintain airway reflexes or spontaneous
ventilation.
• Cardiovascular function is preserved.
8. General anesthesia
• State of unconsciousness; the autonomic nervous system is unable
to respond to surgical or procedural stimuli.
• Properties of an ideal sedative ;
Anxiolysis - relief of agitation.
Amnesia - lapse in memory for a period of time.
Analgesia - relief of pain.
14. INDICATIONS OF SEDATION
1. Dental procedures
• Root canal
• Tooth extraction
• Cleanings for sensitive individuals
• Dental implants
2. Medical examinations using a scope
• Colonoscopy
• Endoscopy
• Bronchoscopy
3. Radiation therapy
15. 4. Minor surgical procedures
• Biopsies
• Minor bone fracture surgery
• Cardiac ablation procedures
• Electrical cardioversion
• Minor skin surgery
• Vasectomy
• Fix a dislocated joint
• Lumbar puncture
16. CONTRAINDICATIONS OF SEDATION
Absolute Contraindications
• Urgent need for treatment (e.g., hemodynamic instability) that cannot
await sedation
• Hypersensitivity to one of the drugs or to the delivery vehicle*
• Particular to ketamine: Age < 3 months (increased risk of airway
compromise)
• Particular to nitrous oxide: Pneumothorax, pneumomediastinum, bowel
obstruction, or intraocular gas bubble (post-vitreoretinal surgery), which
are sites of air accumulation into which nitrous oxide can expand
17. Relative Contraindications
•Severe cardiopulmonary disease (increased risk of
decompensation from respiratory depression)
•Obstructive sleep apnea
•Obesity or anatomic characteristics (e.g., micrognathia,
macroglossia, short neck, congenital anomalies) that suggest
difficult intubation
•Chronic liver or kidney disease: Some drugs will be metabolized
slowly, leading to prolonged sedation
18. •Patients > 60 years of age (increased risk of decompensation):
PSA drug doses should often be decreased
•Acute alcohol/sedative drug intoxication (increased risk of
respiratory complications): PSA drug doses should be
decreased
•Chronic alcohol or substance use disorder: PSA drug doses
may need to be increased
•Pre-procedural food or drink: Review institution-specific
protocols regarding fasting before PSA
19. COMPLICATIONS OF SEDATION
• Respiratory depression
• Oxygen desaturation
• Hypotension (rarely significant in the absence of concurrent
serious disease or cardiovascular compromise)
• Aspiration (rare)
• Particular to etomidate: Myoclonus (minimal and brief, rarely
clinically significant); adrenal suppression (usually
inconsequential and transient)
20. • Particular to fentanyl: Chest wall rigidity (rigid chest syndrome)
due to too-rapid IV push (infrequent at the low dose used for
analgesia)
• Particular to ketamine: Occasional laryngospasm or apnea
(prevented by adhering to slow push [> 30 to 60 seconds]);
sympathomimetic effects (hypertension, tachycardia, which pose
risk to patients with ischemic heart disease or underlying
hypertension); on recovery, vomiting or emergence reactions
(anxiety/panic/hallucinatory episode), more frequent in adults
than in children
21. In Summary
1. Indications: Any time the patient requires an intervention that
will cause significant discomfort (Pain or anxiety). The level of
sedation needed depends on the amount of pain the patient is
likely to experience, and the necessity of the patient remaining
still during the procedure
2. Contraindications: Operator skill/patient needs/patient
conditions/allergies/High risk of aspiration
3. Complications: Reflect
22. REFERENCES
1. How To Do Procedural Sedation and Analgesia - Injuries; Poisoning - MSD
Manual Professional Edition
https://www.msdmanuals.com/professional/injuries-poisoning/how-to-
do-anesthesia-procedures/how-to-do-procedural-sedation-and-analgesia
2. https://www.ncbi.nlm.nih.gov/books/NBK551685/
25. INTRODUCTION
• Regional anesthesia is a form of pain management that numbs a
huge part of the body.
• It provides a reversible loss of sensation.
• For a short period of time, motor, sensory and autonomic
functions are inhibited.
• This facilitates the performance of surgical procedures.
27. ADVANTAGES
• It differs from general anesthesia as it does not interfere with
the patient's level of consciousness.
• Significant reduction of perioperative pain
• Easy to administer
• Quicker recovery time
• Fewer side effects than general anesthesia
• Reduced doses of drug used
28. DISADVANTAGES
• Hypotension
• Post lumbar puncture headache
• Neurological and cardiac toxicity
• It is difficult to cover multiple sites of pain
• Infection
• Back pain
29. TOPICAL ANESTHESIA
• It is defined as the application of a local anesthetic to an area of
the body with the intention of numbing that region.
• It causes a superficial loss of sensation in the conjunctiva,
mucous membranes and skin.
• It comes in many dosage forms: creams, ointments, solutions,
eye drops, gels or sprays.
30. • The first local anesthetic to be used was cocaine and it was used
as a topical anesthetic.
• It was discovered to have anesthetic properties, when Albert
Niemann in 1860 tested the drug and noted that it caused
numbing of the tongue.
• In 1884, Karl Koller, an ophthalmic surgeon, demonstrated that
cocaine could be applied to the conjunctiva before surgery.
31. • Some examples of drugs used in topical anesthesia:
a) Lidocaine
b) Benzocaine
c) Tetracaine
d) Dibucaine
e) Eutectic mixture of local anesthetics
32. USES OF TOPICAL ANESTHESIA
• Relieve pain and itching caused by conditions such as sunburn or
other minor burns, insect bites, poison ivy and minor cuts and
scratches.
• In ophthalmology, it is used to numb the surface of the eye before
performing procedures.
• In dentistry, to numb oral tissues before administering a local
anesthetic.
• In otorhinolaryngology, it can be applied before procedures.
33. • For minor penile surgery like circumcision
• For temporary relief of premature ejaculation when applied to
the glans of the penis
34. Skin penetration routes
• There are three pathways to cross the stratum corneum, which is
the main barrier for topical anesthetic agent delivery:
a) Intercellular route
b) Transcellular route - through the cornified cells
c) Trans-appendageal route - through the openings of the hair
follicles and sweat glands
35. 1. Lidocaine
• It is also known as xylocaine
• It is classified as an amide local anesthetic agent
• Its chemical formula is C14H22N2O
Mode of action - the site of action of lidocaine is at sodium ion
channels on the surface of nerve cell membranes. It binds
reversibly to sodium channels from the inside, locking them in the
open state and preventing nerve depolarization.
36. Onset of action - 3 to 5 minutes
Duration of action - 30 minutes to 3 hours
Dosage – 2% xylocaine jelly, 3% lidoRx
Routes of administration - Epidural, spinal infiltration, peripheral
nerve block, intravenous, topical
Its period of stability, with refrigerated storage, is 7 days for
solutions containing epinephrine and 28 days for epinephrine-free
solutions.
37. Metabolism - metabolized predominantly and rapidly by the
liver, and metabolites and unchanged drug are excreted by the
kidneys
Elimination - the excretion of unchanged lidocaine and its
metabolites occurs predominantly via the kidney with less than
5% in the unchanged form appearing in the urine
38. Drug interactions
• Benzodiazepines – When mixed the risk and severity of CNS depression
increases
• Ampicillin – The risk or severity of methemoglobinemia can be
increased when ampicillin is combined with lidocaine
• Caffeine – The metabolism of lidocaine can be decreased when
combined with caffeine
• Cephalosporins – The risk or severity of methemoglobinemia can be
increased
39. Effects on body systems
• Cardiovascular system – Excessive blood levels of lidocaine can
cause changes in cardiac output, total peripheral resistance, and
mean arterial pressure. The net effect is hypotension.
• Central nervous system – High systemic lidocaine concentrations
exert well-known toxic effects including seizures, coma, and
death.
• Gastrointestinal – Lidocaine modulates sensory signaling
pathways involved in pain perception within the gastrointestinal
tract.
40. • Respiratory system - lidocaine increases airway tone and causes airway
narrowing.
• Musculoskeletal system - provides pain relief
Contraindications
• Severe sinoatrial block (without pacemaker)
• Serious adverse drug reaction to lidocaine or amide local anesthetics
• Hypersensitivity to corn and corn-related products (corn-derived
dextrose is used in the mixed injections)
• Concurrent treatment with quinidine, flecainide, disopyramide
• Heart block
42. Side effects
• Blistering, crusting, irritation, itching, or reddening of the skin
• Fast heartbeat
• Fever
• Hoarseness
• Joint pain, stiffness, or swelling
• Large, hive-like swelling on the face, eyelids, lips, tongue, throat,
hands, legs, feet, or genitals
• Noisy breathing
• Tightness in the chest
43. 2. Benzocaine
• Belongs to the amino ester drug class
• Its chemical formula is C9H11NO2
Mode of action
• Benzocaine functions by reversibly binding to and inhibiting
sodium channels in the neuronal cell membrane. Nerve cells
unable to allow sodium into cells cannot depolarize and conduct
nerve impulses.
44. Onset of action – less than a minute
Duration of action – approximately 10 minutes
Route of administration – topical
Dosage – gel/topical solution: 6.3%, 7.5%, 10%, 20%
Metabolism - benzocaine undergoes ester hydrolysis to form 4-
aminobenzoic acid, acetylation to form acetyl-benzocaine, or N-
hydroxylation to form benzocaine hydroxide
45. Elimination - because of limited aqueous solubility, very little is
excreted intact in the urine.
Drug interactions
• The risk or severity of CNS depression can be increased when
benzocaine is combined with a benzodiazepine.
• The metabolism of benzocaine can be decreased when
combined with amphetamine
• The risk or severity of methemoglobinemia can be increased
when amphotericin B and ampicillin is combined
with benzocaine
46. Contraindications
• Severe allergic reactions to ester-type local anesthetics
• Heart arrhythmias
• History of methemoglobinemia
• Children under the age of 2 because of the risk of
methemoglobinemia
• Predisposing medical conditions such as COPD, emphysema, or
coronary artery disease have a higher incidence of developing
methemoglobinemia
48. Summary
• Topical anesthesia is the application of a gel or cream to an area
to numb it in preparation of procedures or alleviate pain
• Used in ophthalmology, dentistry, otorhinolaryngology and other
injuries
• Examples include lidocaine, benzocaine and tetracaine
• They mainly reversibly block nerve conduction near their site of
administration, thereby producing temporary loss of sensation in
that area
49. REFERENCES
1. Morgan and Mikhail's Clinical Anesthesiology 5th edition
2. Medscape
3. Drug bank
4. The National Library of Medicine
52. •Neuraxial anesthesia involves delivery of LAA into the fatty
tissue in epidural space or CSF in subarachnoid
•This is done at the level L4-L5
•So as to avoid injury to the spinal cord
•Terminates at lower border of L1(adults) and L3(children)
•Injury may cause neurological manifestations like
paraplegia
•NA can be epidural, spinal or caudal
53. MECHANISM OF ACTION
• Principle site of action is the nerve roots in epidural and
subarachnoid space
• Blockade of ventral root inhibit efferent action such as skeletal
muscle tone
• Blockade of dorsal root inhibit afferent action such as pain stimuli
• Order of blockade : Starts with >Autonomic, Sensory, Motor
• During recovery, starts with motor then sensory then autonomic
54. EPIDURAL ANESTHESIA
• Delivering LA in epidural space between l.flavum and dura
• Contents of epidural space: blood vessel, fat, nerves, lymphatics
• Given as a single infusion or continuously via a catheter
• Slower onset of action: 10 - 20minutes
• More difficult to perform and needs more LA than spinal
• Can be thoracic, cervical or at lumbar level
• Sacral blockade is called caudal block
56. SPINAL/INTRATHECAL ANESTHESIA
• Delivery of LA into the subarachnoid space having CSF
• Subarachnoid space extend from magnum to S2 (adults),
S3(children)
• Two “pops” are felt. Ligamentum flavum, and the second is
penetration of the dura–arachnoid membrane.
• Successful dural puncture is confirmed by withdrawing the stylet
to verify flow of CSF
60. COMPLICATIONS
1. Hypotension
2. Bradycardia- give atropine
3. Post dural puncture headache
4. Total spinal anesthesia - blockade reaches cranium and may
cause medulla paralysis
5. High spinal - blockade high enough to cause diaphragm
paralysis
6. Epidural abscess
7. Epidural hematoma
61. 1. HYPOTENSION
• Occurs as a result of sympathetic blockade leading to vasodilation
• Subsequent venous pooling, decreased venous return
• And reduced cardiac output
• Autotransfusion may be accomplished by placing the patient in a
jack-knife position
• A bolus of intravenous fluid (5–10 mL/kg) may be helpful in
patients who have adequate cardiac and renal function
• If refractory, give vasopressors e.g., ephedrine
62. 2. POST DURAL PUNCTURE HEADACHE
• Mainly in younger patients and women
• Mostly 14-18hours post puncture
• Frontal or occipital, +/- diplopia
• Occurs secondary to CSF loss> brain sinks/displaces> traction on
pain sensitive areas - thalamus and tentorium
• Bridging veins may tear causing subdural hematoma
• Treatment - resolves spontaneously
• Bed rest, IV fluids, blood patch, caffeine citrate increases CSF
production
63. TOTAL AND HIGH SPINAL ANESTHESIA
Total spinal anesthesia - Blockade reaches cranium and may cause
medulla paralysis.
Features - hypotension, mydriasis, loss of consciousness
Management - intubation, fluid resuscitation
High spinal anesthesia - blockade high enough to cause diaphragm
paralysis
64. CAUDAL ANESTHESIA
• Epidural sacral blockade is called caudal block
• Mostly given in children at the sacral hiatus via sacrococcygeal l.
• Dural sac in adults-S1; children-S2
• Used for urogenital, rectal, inguinal and lower limb surgeries
• PSIS and the hiatus form an equilateral triangle
• Complications - total spinal, intraosseous injection thus systemic
toxicity
65. SADDLE ANESTHESIA
• Spinal given in a seated position
• Patient remains seated for 5-10mins
• Lower lumbar nerves and sacral nerves are blocked
66. IN SUMMARY…
• Neuraxial anesthesia refers to central blockade of nerves
• They can be used as primary anesthesia or together with GA or for
analgesia
• Epidural blockade is more tedious, needs more LAA, has a slower
onset of action
• Spinal involves giving LAA inside CSF. Associated with higher risk of
postdural puncture headache
• Factors that determine spread of the LAA in the CSF ARE:
67. …
• Baricity of LAA, dosage used, and position of patient during
injection and after injection
• Neuraxial anesthesia is mostly indicated in lower body surgery
• Is contraindicated where there is a site infection, coagulopathy or
patient refusal among others
• It is relatively cheaper, avoids systemic effects of GA and alleviates
the surgical stress response
68. REFERENCES
1. Morgan and Mikhail's Clinical Anesthesiology 5th Edition
2. Short Textbook of Anesthesia 1st Edition
3. Medscape
4. AMBOSS
71. • A peripheral nerve block refers to injection of local anesthetic agents
around nerves in the peripheral nervous system to achieve reversible
numbing of pain conduction in the corresponding innervated tissue.
• General indications include: non-thoracoabdominal surgery, minor surgical
procedures, wound repair in which infiltration anesthesia may distort the
anatomy, when a large area of anesthesia is required, and for postoperative
pain control.
72. BLOCK TECHNIQUES
1. Field Block Technique
• Field block - local anesthetic injection that targets terminal cutaneous
nerves.
• Used by surgeons to minimize incisional pain; as supplementary or sole
anesthetic for minor, superficial procedures; for procedures of the neck or
shoulder, forearm, and the medial leg or ankle joint
• Contraindicated where they obscure the operative anatomy, or where local
tissue acidosis from infection prevents effective local anesthetic functioning.
73. 2. Paresthesia Technique
• A block needle is placed in proximity to the target nerve or plexus; when
direct contact is made with a sensory nerve, a paresthesia (abnormal
sensation) is elicited in its area of sensory distribution.
3. Nerve Stimulation Technique
• An insulated needle, wire, nerve stimulator, and grounding electrode are
attached to the patient to create a circuit.
• When the insulated needle is placed in proximity to a motor nerve, muscle
contractions are induced, and local anesthetic is injected (30-40mL).
74. 4. Ultrasound
• May be used alone or combined with other modalities.
• Uses high-frequency sound waves emitted from piezoelectric crystals; travel
at different rates through tissues of different densities; return a signal to that
is converted into a 2D grayscale image.
• Sound passes easily – hypoechoic – appear dark or black on the ultrasound
screen. More sound reflected – hyperechoic – appear brighter or white.
• Needle insertion can pass either parallel (“in plane”) or not parallel (“out of
plane”) to the plane of the ultrasound waves. Injected volume 10-30mL.
75.
76. 5. Continuous Peripheral Nerve Blocks/ Perineural Local Anesthetic Infusion
• Percutaneous catheter is placed adjacent to a peripheral nerve, followed by
local anesthetic administration to prolong a nerve block.
• Types of catheters: non-stimulating and stimulating; flexible and more rigid;
through-the-needle and over-the- needle.
• Long-acting local anesthetics (e.g., ropivacaine) are often used as they
provide a more favorable sensory-to-motor block ratio (optimizing analgesia
while minimizing motor block).
77. • Methods of administration: repeated bolus doses, basal infusion, as a
combination, using a portable infusion pump.
• Serious complications (relatively rare), include systemic local anesthetic
toxicity, catheter retention, nerve injury, infection, and retroperitoneal
hematoma formation. In addition, a perineural infusion affecting the femoral
nerve increases the risk of falling.
78. UPPER EXTREMITY PERIPHERAL NERVE BLOCKS
Brachial Plexus
• Local anesthetic may be deposited at any point along the brachial plexus,
depending on the desired block effects
• Interscalene for shoulder and proximal humerus surgical procedures; and
supraclavicular, infraclavicular, and axillary for surgeries distal to the mid-
humerus.
79.
80.
81. 1. Interscalene Block
• Indications: Procedures involving the shoulder and upper arm.
• Contraindications: Local infection, severe coagulopathy, local anesthetic
allergy, patient refusal, severe pulmonary disease or preexisting contralateral
phrenic nerve palsy.
• Complications: Dyspnea, hypercapnia, and hypoxemia (hemidiaphragmatic
paresis), Horner’s syndrome, hoarseness, respiratory distress, vertebral artery
injection (suspect if immediate seizure activity is observed), spinal or epidural
injection, and pneumothorax.
82. • Positioning: With the patient supine and their head rotated 30° or less to the
contralateral side; palpate the interscalene groove.
• Techniques:
a) Nerve Stimulation: Interscalene groove palpated; skin anesthetized; block
needle inserted and advanced to optimally elicit a motor response of the
deltoid or biceps muscles.
b) Ultrasound: Identification of the SCM muscle and interscalene groove;
transducer placed perpendicular to interscalene muscles; needle advanced
through the middle scalene muscle until it passes through the fascia
anteriorly into the interscalene groove.
83. 2. Supraclavicular Block (“Spinal of the arm”)
• Indications: Surgical procedures at or distal to the elbow
• Historically, fell out of favor due to the high incidence of pneumothorax that
occurred with paresthesia and nerve stimulator techniques. Use of
ultrasound guidance has theoretically improved safety.
• Complications: Ipsilateral phrenic nerve palsy, Horner’s syndrome, recurrent
laryngeal nerve palsy, pneumothorax and subclavian artery puncture.
84. • Techniques:
a) Ultrasound: Patient supine and head turned 30° toward the contralateral
side; transducer placed in the supraclavicular fossa superior to the
clavicle and angled slightly toward the thorax; needle inserted just
cephalad or lateral to the ultrasound transducer; local anesthetic spread
should be visualized surrounding the plexus after careful aspiration for
the nonappearance of blood and incremental injection.
85. 3. Infraclavicular Block
• Indications: Procedures at or distal to the elbow.
• Contraindications: Patients with vascular catheters in the subclavian region,
patients with an ipsilateral pacemaker.
• Complications: Vascular puncture, pneumothorax (although less common
than with supraclavicular block).
86. • Techniques:
a) Nerve Stimulation: Patient supine and head turned to the contralateral
side; coracoid process is identified - subclavian artery and brachial plexus
run deep to it; needle inserted and advanced until a motor response (finger
flexion or extension) is elicited.
b) Ultrasound: Patient in the supine position; transducer is placed in the
parasagittal plane 2 cm medial and 2 cm caudad to the coracoid process;
needle is inserted 2–3 cm cephalad to the transducer, between the axillary
artery and the posterior cord.
87. 4. Axillary Block
• Indications: Anesthesia of the entire arm distal to the elbow.
• Contraindications: Local infection, neuropathy, bleeding diathesis.
• Because the axilla is highly vascularized, there is a risk of local anesthetic
uptake through small veins traumatized by needle placement.
• Techniques:
a) Trans-arterial: Palpate and immobilize the axillary artery; needle is inserted
high in the axilla until bright red blood is aspirated; slightly advanced until
blood aspiration ceases; 30–40 mL of local anesthetic is typically used.
88. b) Nerve Stimulation: Palpate and immobilize the axillary artery; needle
inserted proximal to the palpating fingers to elicit muscle twitches in the
hand; careful aspiration is performed and local anesthetic is injected.
c) Ultrasound: Transducer used to visualize the axillary artery and vein in
cross-section; brachial plexus can be identified surrounding the artery;
needle is inserted under direct visualization; 10mL of local anesthetic is
then injected around each nerve.
89. 5. Blocks of the Terminal Nerves
• Indications: for minor surgical procedures with a limited field or as a
supplement to an incomplete brachial plexus block.
• Terminal nerves may be anesthetized anywhere along their course, but the
elbow and the wrist are the two most favored sites.
• Examples:
90. A. Median Nerve Block
• At the elbow: Brachial artery is identified in the antecubital crease; needle
inserted just medial to the artery; directed toward the medial epicondyle until
wrist flexion or thumb opposition is elicited; 3–5 mL of local anesthetic
injected.
• At the wrist: the palmaris longus tendon identified; needle inserted just
medial and deep to the palmaris longus tendon; 3–5 mL of local anesthetic is
injected.
• Ultrasound technique can also be used.
91. B. Ulnar Nerve Block
• At the elbow: Needle is inserted approximately one fingerbreadth proximal
to the arcuate ligament; advanced until fourth/fifth digit flexion or thumb
adduction is elicited; 3–5 mL of local anesthetic is then injected.
• At the wrist: Ulnar artery pulse is palpated; needle inserted just medial to
the artery; 3–5 mL of local anesthetic is injected. Ultrasound may also be
used.
92. C. Radial Nerve Block
• At the elbow: Biceps tendon is identified in the antecubital fossa; needle
inserted just lateral to the tendon; directed toward the lateral epicondyle until
wrist or finger extension is elicited; 5 mL of local anesthetic is then injected.
• At the wrist: Superficial branch of the radial nerve lies just lateral to the radial
artery, which can be easily palpated lateral to the flexor carpi radialis tendon;
3–5 mL local anesthetic is injected lateral to the artery.
• Ultrasound technique may also be used.
93. D. Musculocutaneous Nerve Block
• To target the musculocutaneous nerve following an axillary block; Needle
redirected superior and proximal to the artery; coracobrachialis muscle is
pierced; 5–10 mL of local anesthetic is injected, with or without elicitation of
elbow flexion.
• At the elbow: Insertion of the biceps tendon is identified; needle is inserted
1–2 cm laterally; 5–10 mL of local anesthetic is then injected as a field block.
94. E. Digital Nerve Blocks
• Indications: Minor operations on the fingers and to supplement incomplete
brachial plexus and terminal nerve blocks.
• Procedure: Needle is inserted at the medial and lateral aspects of the base
of the selected digit; 2–3 mL of local anesthetic is inserted without
epinephrine.
95. 6. Intercostobrachial Nerve Block
• Supplies cutaneous innervation to the medial aspect of the proximal arm
and is not anesthetized with a brachial plexus block.
• Procedure: Patient supine with arm abducted and externally rotated; starting
at the deltoid prominence and proceeding inferiorly, a field block is
performed in a linear fashion using 5 mL of local anesthetic, extending to the
most inferior aspect of the medial arm.
96. PERIPHERAL NERVE BLOCKS OF THE TRUNK
• Superficial Cervical Plexus Block: Cutaneous analgesia for surgical procedures
on the neck, anterior shoulder, and clavicle.
• Intercostal Block: Thoracic and upper abdominal surgery, and relief of pain
associated with rib fractures, herpes zoster, and cancer.
• Paravertebral Block: Surgical or postop analgesia for procedures of thoracic or
abdominal wall, mastectomy, inguinal or abdominal hernia repair, and more
invasive unilateral procedures such as open nephrectomy.
• Transversus Abdominis Plane (TAP) Block: Surgical anesthesia for minor,
superficial procedures on the lower abdominal wall, or postop analgesia for
procedures below the umbilicus.
97. PERIPHERAL NERVE BLOCKS OF HEAD AND NECK
• Maxillary Nerve Block: Pain reduction and/or abscess drainage for maxillary
teeth, laceration repair of upper lip and midface.
• Mandibular Nerve Block: Pain reduction and/or abscess drainage for
mandibular teeth, laceration repair of lower lip and chin.
98. Summary
1. Block techniques – field block, paresthesia, nerve stimulation,
ultrasound, continuous
2. Upper limb blocks – interscalene, supraclavicular, infraclavicular, axillary
3. Trunk blocks – superficial cervical plexus, intercostal, paravertebral, TAP
4. Head and neck blocks – maxillary, mandibular
99. References
1. Morgan and Mikhail’s Clinical Anesthesiology; 5th Edition
2. www.medscape.com
3. www.amboss.com
103. FEMORAL NERVE BLOCK
• Femoral nerve innervates the main hip flexors and knee extensors
• Most medial branch is saphenous nerve innervating medial leg and ankle
joint
• Indications: provide postoperative analgesia for hip, thigh, knee and ankle
procedures
• Contraindications: previous ilioinguinal surgery, local infection, tumor
peritoneal infection, large inguinal lymph nodes, femoral neuropathy
• Techniques: nerve stimulation, ultrasound, fascia Iliaca technique
104. LATERAL FEMORAL CUTANEOUS NERVE BLOCK
• Provides sensory innervation to the lateral thigh
• Indications: as a supplement to femoral nerve block or limited anesthesia of
the lateral thigh
Procedure
• Patient positioned supine or lateral
• The point 2cm medial and 2cm distal to the ASIS is identified
• A short 22-gauge block needle is inserted and directed laterally observing for
a pop as it passes through the fascia lata
• A field block is performed with 10-15ml of local anesthesia
105. OBTURATOR NERVE BLOCK
• Contributes sensory branches to the hip and knee joints , medial thigh and
innervates adductor of the hip.
• Indication: required for complete anesthesia of the knee-femoral +sciatic
Procedure
• Identification of pubic tubercle, 10 cm block needle inserted 1.5cm inferior
and laterally
• Advanced posteriorly until bone contact, redirect laterally and caudally 2-4
cm until a motor response
• 15-20 ml of local anesthetic is injected
106. SCIATIC NERVE BLOCK
• Indicated for surgeries of the hip, thigh, knee, lower leg and foot
• Limited application hence used in combination with a femoral or 3-in-1 block
Approaches
• Posterior (classic or Labat) - Sim′s position, greater trochanter, PSIS and sacral
hiatus identified. 25ml used
• Anterior - nerve stimulation and ultrasound. 25 ml used. High risk of vascular
puncture. CI in coagulopathy and vascular grafting
• Subgluteal - nerve stimulation and ultrasound- landmarks easily
identified(greater trochanter and ischial tuberosity), less tissue traversed
• Popliteal - nerve stimulation (posterior or lateral), ultrasound. 30-40 ml.
Excellent coverage for foot and ankle surgery, eases ambulation
107. COMBINED SCIATIC, FEMORAL AND OBTURATOR (3-IN-1)
NERVE BLOCK
• Indication: Pain relief and anesthesia from upper thigh downwards.
• Contraindications: as in spinal anesthesia
• Drug injected in the femoral canal while maintaining distal
pressure resulting in upward spread.
• Upper inner thigh and possibly posterior thigh not covered –
problem with tourniquet applied high on the leg
• Supplementary parenteral analgesia or sedation can be used.
108. LUMBAR PLEXUS BLOCK
• Indications: Procedures on the hip, knee and thigh
• Complete anesthesia of the knee attained with a proximal sciatic
nerve block.
• Highest complications due to close proximity with multiple
sensitive structures: retroperitoneal hematoma, toxicity,
hematoma due to renal capsule puncture
• Landmarks - PSIS and L4
109. SAPHENOUS NERVE BLOCK
• Indication: used mainly in conjunction with a sciatic nerve block to
provide a complete anesthesia below the knee.
Techniques
• Trans-Sartorial - deep to the sartorius muscle (Junction with vastus
medialis and adductor muscle; 5-10 ml
• Proximal saphenous - short block needle inserted 2 cm distal tibial
tuberosity directed medially; 5-10 ml.
• Distal saphenous - medial malleolus identified. 5 ml in a line
running anteriorly around the ankle.
110. ANKLE BLOCK
• Indication: surgical anesthesia of the foot-fast, low technology, low
risk.
• Excessive injectate volume and use of vasoconstrictors avoided -
minimize risk of ischemic complications.
• It include 5 injections - deep peroneal, superficial peroneal,
saphenous posterior tibial and sural nerves.
• Uncomfortable for patient requiring adequate premedication.
• Unlike sciatic nerve block, provides no analgesia for tourniquet pain
and does not allow for perineural catheter insertion.
111. COMPLICATIONS OF PERIPHERAL NERVE BLOCKS
• Toxicity of local anesthetics
• Transient or chronic paresthesia
• Intra-arterial injection, seizures or cardiac arrest
• Block failure - need to supplement or convert to general
anesthesia
• Infection
• Coagulopathy
• Nerve damage
112. SUMMARY
• Lower extremity nerves comprise the lumbosacral plexus branches
• Femoral nerve block seldomly alone provides general anesthesia but often
used to provide postoperative analgesia
• 3-in-1 block is combination of sciatic, femoral and obturator nerve blocks to
provide anesthesia upper thigh downwards
• Complete anesthesia of the knee can be attained with a proximal sciatic nerve
block
• Blockade of sciatic nerve may occur anywhere along its course. Indicated for
surgical procedures of hip, thigh, lower leg and foot
• Popliteal nerve block provide excellent coverage for foot and ankle surgery and
eases ambulation
• A complete ankle block requires 5 nerves
• Complications: toxicity, nerve damage, coagulopathy, infection, block failure,
paresthesia, seizures and cardiac arrest.
113. REFERENCES
1. Short Textbook of Anesthesia 1st Edition
2. Morgan and Mikhail′s Clinical Anesthesiology 5th Edition
3. Medscape
115. • Also known as Bier Block
• August Bier introduced this block in 1908
• 1963, Holmes popularized the Bier Block.
• The Bier Block is a suitable technique for the following:
Surgical procedures involving the arm below the elbow (open procedures or
closed reductions)
Surgical procedures involving the leg below the knee (open procedures or
closed reductions)
Surgical procedures that will be completed within 40-60 minutes
117. Mechanism of Action
Exact mechanism not clearly understood. There appear to be multiple and
complementary mechanisms for producing analgesia and anesthesia.
Initial analgesia is produced by local anesthetic action on major nerve
trunks, small nerves, and nerve endings.
Asphyxia occurs at 20-30 minutes complementing local anesthetic action.
Local anesthetic molecules transverse venous walls into surrounding tissue.
Hypothermia and acidosis result in enhanced local anesthetic activity.
118. Contraindications
• Severe Raynaud’s Disease (intermittent arteriolar vasospasm of the distal
limbs after cold or emotional stimuli)
• Sickle Cell Disease (IVRA is relatively contraindicated, unless meticulous
exsanguination of the limb takes place prior to cuff inflation)
• Seizure disorder
• Hypersensitivity to prilocaine or lidocaine
• Crush injury to the limb, IVRA may provoke further tissue damage secondary
to hypoxia.
119. • Age - young children are generally not amenable to IVRA alone,
however in combination with sedation and additional analgesia it
can be used successfully.
• Patients should be starved, as there may be a possibility of
conversion to a general anesthetic, alternatively the patient may
require sedation in addition to IVRA to improve co-operation.
120. Local Anesthetic Choice
Preservative free prilocaine and lidocaine are acceptable choices.
Both have relatively low toxicity and a high therapeutic index.
The concentration for both should be 0.5%.
Never substitute other local anesthetics.
The local anesthetic should NOT contain epinephrine, it should be
pain free.
121. • PRILOCAINE
It’s the drug of choice its least toxic with the largest therapeutic
index.
It’s the drug that is metabolized to O-toluidine which produces
methaemoglobinemia in a dose dependent fashion.
Onset is 2-15 minutes and duration 1-4hours.
Dosage: The usual dose for an adult is 30-40 ml of 0.5% prilocaine
The leg, larger volume 50-60ml. Max of 6mg/kg.
124. Complications of Bier Block
• Tourniquet discomfort.
• Rapid return of sensation after tourniquet release, resulting in subsequent
pain.
• Toxic reactions from malfunctioning tourniquets or deflating the tourniquet
prior to 20-25 minutes. This will result in a large volume of local anesthetic
being rapidly introduced into the circulation. The patient may develop
dizziness, nausea, vomiting, tinnitus, perioral tingling, muscle twitching, loss
of consciousness, and convulsions. Avoidable deaths have occurred.
125. Management of Systemic Toxicity of Local Anesthetics
• Airway - Maintain the patient’s airway, administer 100% oxygen and call for
help. Turn the patient onto their side; lower their head if possible to prevent
aspiration.
• Breathing - Start ventilation if breathing inadequate. Intubate if indicated.
• Circulation - Pulse check. If in cardiac arrest start CPR. Assistant to start
monitoring ECG, pulse oximetry, and blood pressure.
• Convulsions - IV 5mg diazepam or 50mg - 200mg thiopentone. Muscle
relaxation if required.
• Hypotension - IV ephedrine 3-6mg increments, elevate legs, IV fluid bolus
126. Advantages of Bier Block
•Easy to administer
•Safe technique when used appropriately
•Low incidence of block failure
•Rapid onset and recovery
•Patient is awake during procedure
•Controllable extent of anesthesia
127. Disadvantages of Bier Block
•Only for short procedures
•Patients may experience tourniquet pain after 20-30 min
•Sudden CVS collapse if local anesthetic is released into the
circulation too early
•Rapid recovery may lead to post operative pain
128. Summary
• IVRA is a simple and effective regional anesthetic technique to
perform, provided that the cuff is checked, and its’ pressure
monitored.
• Resuscitation and monitoring equipment should be readily
available when conducting IVRA.
129. REFERENCES
1. Haasio J Hippala S Rosenberg PH. Intravenous regional anaesthesia of the
arm. Anaesthesia 1989;44:19 -21
2. Gentili M Bonnet F Bernard JM. Adding clonidine to lidocaine for IVRA
prevents tourniquet pain. Anesthesia Analgesia 1999
Operator skillset (training). If the person performing the sedation lacks the skillset to secure an unstable airway, from intubation to cricothyrotomy, PSA is not an option.
Nerves are best imaged in cross-section, where they have a characteristic honeycomb appearance (“short axis”).
After careful aspiration for the nonappearance of blood, 30–40 mL of local anesthetics injected in 5-mL increments while visualizing local anesthetic spread around the brachial plexus.
Local anesthetic is the primary medication infused, as adjuvants do not add benefits to perineural infusions (unlike single-injection peripheral nerve blocks).
Roots: C5–7 are most densely blocked with this approach; and the ulnar nerve originating from C8 and T1 may be spared. (Hence are not appropriate for surgery at or distal to the elbow). For complete surgical anesthesia of the shoulder, the C3 and C4 cutaneous branches may need to be supplemented with a superficial cervical plexus block or local infiltration.
Having the patient lift and turn the head against resistance often helps delineate the anatomy.
Nerves: The supraclavicular block does not reliably anesthetize the axillary and suprascapular nerves, and thus is not ideal for shoulder surgery. Sparing of distal branches, particularly the ulnar nerve, may occur.
Brachial plexus block at the level of the cords providing excellent anesthesia for procedures at or distal to the elbow
The upper arm and shoulder are not anesthetized with this approach.
As with other brachial plexus blocks, the intercostobrachial nerve (T2 dermatome) is spared.
The axilla is also a suboptimal site for perineural catheter placement because of greatly inferior analgesia versus an infraclavicular infusion, as well as theoretically increased risks of infection and catheter dislodgement.
Transarterial technique has fallen out of favor due to the trauma of twice purposefully penetrating the axillary artery along with a theoretically increased risk of inadvertent intravascular local anesthetic injection.
Nerve stimulation - Although a single injection of 40 mL may be used, greater success will be seen with multiple nerve stimulations (i.e., two or three nerves) and divided doses of local anesthetic.
Addition of a vasoconstrictor (epinephrine) has been claimed to seriously compromise blood flow to the digit; however, there are no case reports involving lidocaine or other modern local anesthetics to confirm this claim.
The intercostobrachial nerve originates in the upper thorax (T2) and becomes superficial on the medial upper arm.
Intercostal blocks result in the highest blood levels of local anesthetic per volume injected of any block in the body, and care must be taken to avoid toxic levels of local anesthetic.
The intercostal block has one of the highest complication rates of any peripheral nerve block due to the close proximity of the intercostal artery and vein (intravascular local anesthetic injection), as well as underlying pleura (pneumothorax).
