Spinal anaesthesia involves injecting local anaesthetic into the subarachnoid space to block spinal nerves. It was first introduced in the late 1800s. The spinal cord and nerves are surrounded by meninges including the dura, arachnoid and pia mater. Cerebrospinal fluid flows in the subarachnoid space. Spinal anaesthesia is performed using a small needle inserted between vertebrae to access this space and inject anaesthetic. The level and extent of nerve blockade depends on factors like drug used, dose, patient positioning and anatomy. It provides anaesthesia for surgeries below the level of injection while sparing consciousness above.

1. SPINAL & EPIDURAL
ANAESTHESIA
Dr. Chandrika Bhut
Assistant Professor
Dept. Of Anaesthesiology
GMC, Bhavnagar

2. SUBARACHNOIDBLOCK
DEFINITION
Spinal anaesthesia is
the regional
anaesthesia obtained
by blocking the spinal
nerves in the
subarachnoid space.

3. HISTORY
Corning, in 1885, accidentally
administered cocaine intrathecally
Quincke, in 1891, - made use of
spinal puncture in diagnosis
August Bier, of Greifswald,
Germany, in 1898, introduced the
technique of spinal anaesthesia.
Pitkin popularized the method of
introducing agents intrathecally.
QUINCKE
AUGUST BIER

4. Spinal Column Anatomy
 Vertebra
 Vertebral Body
 Pedicles Anterior (2) &
Laminae Posterior (2)
 Transverse Process –
Junction of the Pedicles
and Laminae
 Spinous Processes –
Joining of the Laminae
 Intervertebral Disks

5. The spine is composed of the vertebral
bones and fibrocartilaginous
intervertebral disks . There are 7
cervical, 12 thoracic, 5 lumbar,5 sacral
and 4-5 coccygeal vertebra
-Vertebral column has:
2 primary curves which are concave
anteriorly-thoracic and pelvic.
2 secondary curves which are convex
anteriorly-cervical and lumbar.
All the cervical vertebrae are horizontal
except for the last which is slightly
inclined downwards with progressive
increase in angle of inclination of the
vertebra as we move down the spine

6. Anatomy of ligaments
Supraspinous ligament
The supraspionous ligament is a strong,
thick, fibrous band connecting the
apices of the spines from the seventh
cervical to the sacrum. Above C-7 it
blends with ligamentum nuchae
in neck & attaches to external
occipital protuberance of skull
Interspinous ligament
The interspinous ligament is thin,
fibrous structure connecting adjacent
spines. The fibers are almost
membranous and extend from the apex
and upper surface of a lower spine
towards the root and inferior surface of
the lower vertebrae.

7. 3) Ligamentum flavum:
- most important ligament
-consists of yellow elastic tissue
-fibres are perpendicular in direction
- extends between lamina from the
anterior inferior surface of the
upper lamina downwards to the
anterior superior
surface of the lower lamina.
- extends from foramen magnum to
sacral hiatus.
- although portrayed as a single
ligament, it is composed of two
ligaments right and left,which join
in the middle forming acute angle
with a ventral opening.

8. Ligament thickness,distance to dura and
skin to dura distance vary with area of
vertebral canal as follows

9.  Meninges of spinal cord:
1) Duramatter.
2) Arachnoidmatter
3) Piamatter—firmly attached to spinal cord.
Duramatter: forms sac around cord
- Continuation of cranial dura matter
-extends from foramen magnum to S2 vertebrae.
-potential space between duramatter and arachnoid matter is
called subdural space which contains small amount of
serous fluid.
Arachnoidmatter : delicate non-vascular structure, closely
attached to dura.
Piamatter: highly vascular thin membrane covering cord,
terminates at phylum terminalae

10. Sub arachnoid space :
- potential space lined externally by
arachnoid matter and internally by pia
matter close to spinal cord.
- Although spinal cord ends at L1 in
adults, the space continues to S2.
- CONTENTS:
CSF
Spinal nerves
Trabecular network
Blood vessels that supply the spinal
cord
Lateral extensions of pia mater and
dentate ligaments, which supply lateral
support from spinal cord to dura
- Shape :
- annular (3mm) – Cervical , thoracic
region.
circular – lumbar

11. PHYSIOLOGY OF CSF
• CSF is an ultrafiltrate of the blood plasma.
VOLUME OF CSF
• Total Volume- 120-150ml.
• 20-25ml- in ventricles
• 30-90ml – Cisterna reservoir at the base of brain.
• 25-30ml- Spinal subarachnoid space.
FORMATION OF CSF
• 50 to 70% is formed by ultrafiltration through the choroid plexus
• Formed around blood vessels and along ventricular walls.
• Total production 550 ml/day
Absorption of csf :
Cranial region-through arachnoid villi
Spinal region -venous plexus
• .
CONTROL OF CSF PRODUCTION
• Under sympathetic control
• Stimulation of superior cervical ganglia increases production and fluid pressure.

13. CHARACTERISTICS OF CSF
• CSF pressure-70-180mm of H2O in recumbent position,
375 -550 mm of H2O in vertical position.
• PH-7.4-7.6
• Specific gravity- 1.003-1.009
• Density- 1.0003 (at37oc)

14. PREOPERATIVE EVALUATION AND PREPARATION FOR SAB
1. Informed written consent
2. Physical Examination of spine for any anatomical abnormality like
kyphosis or scoliosis
3. Laboratory Tests:Hb,TLC,DLC,PLT,PT,INR,BT,CT,RBS,RFT,LFT AND
S.electrolytes
INDICATIONS OF SPINAL ANAESTHESIA
• Surgeries for lower extremities, hip, perineum, lower abdomen.
• Upper abdominal procedures- cholecystectomy
• Urologic endoscopic surgery -TURP
• Rectal Surgeries-Sacral anaesthesia
• Obsetrics-LSCS.
.

15. Relative contraindications
• Cardiac disease-severe
ischaemic heart disease
• Neurological disease
• Major spinal
abnormalities
•Patient refusal
•Shock, hypovolaemia
•Skin infection at injection site
•Systemic infection
•Increased ICT
•Coagulopathy
•Therapeutic anticoagulation
CONTRAINDICATION OF SAB
Absolute Contraindications

16. SPINAL ANAESTHESIA-TECHNIQUE
NEEDLES
The standard spinal needle-
Three parts .Hub with lever lock connection, cannula, stylet
- Points of cannula are bevelled and have sharp edges. Cannulae made of
stainless steel should be stiff, flexible and resistant to breakage.
Sizes- 16 G to 30 G
Length- 3.5 to 4 inches
NEEDLES CLASSIFIED
1. Standard bevelled with cutting edges-
Quincke, Babcock
2. Pencil point needle with conical point with no cutting edges- Sprotte or
whitacre.

18. Structures pierced by spinal needle
1.Skin
2.Subcutaneous tissue
3.Supraspinous ligament
4.Interspinous ligament
5.Ligamentum flavum
6.Dura
7.Arachnoid Membrane

19. POSITIONS
L.P. is most easily
performed when there is
maximum flexion of
lumbar spine .By this
ligaments get stretched and
space is open. Positions for
SAB are:
1)Sitting position
2)Lateral position
3)Prone jackknife position

20. SITTING POSITION
• The patient is placed with the
buttocks near the edge of the table,
and the legs over the opposite edge
with the feet supported on a stool.
• The patient rests his elbow on his
thighs, or folds his arms forwards
over pillows, and flexes the neck.
• An assistant should support the
patient from the front; every effort
should be made to see that the back
remains vertical & open up the
lumbar vertebral space.

21. • Preferred for obese patients and saddle block
anaesthesia
• Advantage- Proper curvature of back is obtained

22. LATERAL POSITION
. Ideal positioning
consists of having the
back of the patient
parallel to the edge of
the bed closest to the
anaesthetist, knees
flexed to the abdomen,
and neck flexed

23. Prone Jackknife
• appropriate for rectal, perineal, or lumbar procedures
• Patient can position himself
• Hypobaric solution of LA is used
• Paramedian approach should be used
• CSF has to be aspirated

24. LANDMARKS FOR SPINAL
ANAESTHESIA
• Vertebral Spinous processes and
the iliac crests
• Spinous processes clearly define
the midline.
 First prominent spinous process –
spine of C7
 Most prominent spinous process –
spine of T1
T7 lies opposite to the inferior angle of
scapula.
Line drawn between the iliac crests-
intercristine or Tuffier’s line crosses the
4th lumbar vertebrae.

25. RECOMMENDATIONS FOR SAFE. SPINAL
TECHNIQUE
1. Scrub hands according to aseptic surgical technique
2. Use sterile gloves
3. Use aseptic technique when opening tray.
4. Cleanse the skin prior to needle puncture.
5. Touch only sterile articles once gloved.
6. Needle directed just under and parallel to spinous process
7. Avoid repeated traumatic punctures.
8 Use approved local anaesthetic agents in std conc

26. MIDLINE APPROACH
• Palpate space
• Local infiltration.
• Needle directed just under and
parallel to spinous process
• Bevel parallel to dural fibers
• Two resistance- First
Ligamentum flavum and then
duramater
• Verify free flow of CSF
• Inject the drug.
APPROACHES-MIDLINE,PARAMEDIAN
AND TAYLOR

27. PARAMEDIAN OR LATERAL APPROACH
• Useful for-Arthritic or deformed spine
• Space is chosen and needle inserted 1.5 cm lateral to the
midline at an angle of 25o with the needle directed towards
the center.
TAYLOR’S APPROACH
Useful for- Arthritic spine, fused spine.
The needle should be inserted at a point 1 cm medial
and inferior to the posterior superior iliac spine,
then angled cephalad 45-55 degrees. This should
be medial enough to reach the midline at the L5
spinous process. After needle insertion, the first
significant resistance felt is the ligamentum
flavum, and then the dura mater is punctured to
allow free flow of CSF as the subarachnoid space
is entered

28. Practical Problems
The spinal needle feels as if it is in the right position but no CSF appears. Wait at
least 30 seconds, then try rotating the needle 90 degrees and wait again. If there is still
no CSF, attach an empty 2ml syringe and inject 0.5-1ml of air to ensure the needle is
not blocked then use the syringe to aspirate whilst slowly withdrawing the spinal
needle. Stop as soon as CSF appears in the syringe.
Blood flows from the spinal needle. Wait a short time. If the blood becomes pinkish
and finally clear, all is well. If blood continues to drip, then space should be changed
The patient complains of sharp, stabbing leg pain. The needle has hit a nerve root
because it has deviated laterally. Withdraw the needle and redirect it more medially
away from the affected side
.
Wherever the needle is directed, it seems to strike bone. Make sure the patient is still
properly positioned with as much lumbar flexion as possible and that the needle is still
in the mid-line. It might be better to attempt a paramedian approach to the dura.

29. FACTORS POSTULATED TO BE RELATED TO
SPINALANAESTHETIC BLOCK HEIGHT
AGE
• Spinal and epidural spaces become smaller with  age – higher
distribution of drug and higher level of block
OBESITY
• Increase in intra-abdominal pressure results in increase in
pressure in epidural space and decreased subarachnoid space and
hence higher level of block
PREGNANCY
• Increase in intra-abdominal pressure
• Increase in volume of epidural venous plexus - Small
subarachnoid spaces hence higher level of block

30. INTRAABDOMINAL PRESSURE
• Changes resulting from increased intra-abdominal pressure include
collateral flow through epidural venous plexus and higher distribution of
the drug
SPINAL CURVATURE
• Abnormal curvature has an effect on technical aspects
• Changes the contour of Subarachnoid space.
POSITION
• Hyperbaric solutions in the sitting position cause the solution to gravitate
into the caudal areas.
RATE OF INJECTION
• Slow injections - low level of anaesthesia
• Rapid injections - high level of anaesthesia

31. Volume/Dose/Concentration
• Difficult to change one factor alone
• Most studies show no effect of volume or
concentration
• Dose may have a significant effect on block
height:
– Two studies showed significantly lower blocks
with 10mg vs. 15 or 20 mg isobaric bupivicaine
.

32. Effect of speed of injection and
volume on LA spread

33. Baricity
• Ratio of the density
(mass/volume) of the LA
solution divided by the
density of CSF (1.0003)
– Hypobaric = LA +
distilled water, <0.9990
– Isobaric = LA + saline
– Hyperbaric = LA +
dextrose, > 1.0010
• Affected by gravity and
positioning

34. • Head down position- hyperbaric solution will
move cephalad; hypobaric solution will move
caudally.
• Head up position- hyperbaric solution will
move in a caudal direction; hypobaric solution
will move in cephalad direction.
• Lateral position- hyperbaric solution will move
toward the dependent area; hypobaric solution
will move towards the non-dependent area.
• Isobaric solutions- will stay in the general area
of injection regardless of the position.

35. Site of injection: the level that you place the
local anesthetic will influence the spread of
local anesthetic. If you place your medication
at L2 it will cover higher levels than if you
inject it at L5.

36. Barbotage
• The technique first was described by Bier and consists of the injection
of the anesthetic solution into the subarachnoid space, immediate
withdrawal of a portion of the solution and reinjection. This may be
repeated. The to-and-fro movement agitates the injectate in the
spinal fluid, and the currents mix the agent more completely and
carry the agent more extensively and to higher levels.
• Caution must be observed and each operator must learn the results
of his barbotage

37. LEVEL OF ANAESTHESIA
SEGMENTAL LEVELS
• Perineum S1-S4
• Inguinal region L1
• Umbilicus T10
• Subcostal arch T6-T8
• Nipple line T4
• Second intercostals space T2
• Clavicle C3 –C4
SEGMENTAL LEVELS OF SPINAL REFLEXES
• Epigastric T7 and T8
• Abdominal T9-T12
• Cremasteric L1- L2
• Plantar S1-S2
• Knee jerk L2-L4
• Ankle jerk S1-S2

39. ORDER OF BLOCK
Autonomic fibers (mediated by C fibers) are most sensitive as
they are smallest and non-myelinated, are blocked earliest
followed by sensory and the motor fibers.
Autonomic level is tested by temperature, sensory by pin prick
and motor by lower limb movements.

40. Differential Block with SAB
• Sympathetic Block
– 2-6 dermatomes
higher than the
sensory block
• Motor Block
– 2 dermatomes
lower than sensory
block
Sensory
Motor
Sympathetic
T5

41. SEQUENCE OF NERVE MODALITY BLOCK
1. Vasomotor Block- dilatation of skin vessels.
2. Block of cold temperature fibers. Modified Bromage Scale
3. Sensation of Warmth by patient
4. Temperature discrimination is lost
5. Slow pain
6. Fast pain
7. Tactile sense lost
8. Motor paralysis
9. Pressure sense abolished
10. Proprioception
During recovery, anaesthesia recedes from head and feet areas towards the
middle i.e a point near site of anaesthetic agent

42. INDIRECT EFFECTS
Sympathetic blockade is the major determinant of physiological responses.
I. HYPOTENSION:CAUSES
1. Paralysis of vasoconstrictor nerve fibers- arteriolar paralysis
• Venous dilatation
• Vasodilatation cause decreased venous return with decreased cardiac output
2. Direct action on medullary centers
3. Loss of skeletal muscle tone.
4. Paralysis of nerve supply to adrenal glands with decreased catecholamine release

43. II. CARDIAC EFFECTS
Heart rate slows down because of:
• Paralysis of cardioaccelator nerves
• Decreased Venous return which leads to
• Decreased right heart pressure and hence decrease heart rate. (bainbridge reflex)
• The baroraceptors normally respond to fall in blood pressure by tachycardia(Marey’s
Law).But In spinal anaesthesia bainbridge reflex predominates.
III.RESPIRATORY EFFECTS
• Vital Capacity decreases from 4 to 3.73 L
• Decrease in expiratory reserve volume related to paralysis of abdominal muscles necessary
for forced exhalation.
• Respiratory arrest occurs due to hypoperfusion of respiratory centre caused by high or total
spinal’
• Peripheral pooling of blood results in decreased alveolar blood supply which leads to
decreased oxygen supply and hence reflex bronchodilation.

44. • IV. GASTROINTESTINAL EFFECT
• Sympathetic block and parasympathetic over activity
• Contracted gut – intestines active- segmental movements
• Increase peristaltic activity
• Increase in gastric emptying, relaxed sphincters.
• Therefore post operative period of fasting is enhanced to avoid paralytic ileus
and patient is kept NBM till effect of spinal weans off’

45. ENDOCRINE EFFECTS
Spinal Anaesthesia is able to block the sympathetic stimulations caused by
surgical stress.
• Blockade of Sympathetic afferents will prevent increase in plasma prolactin,
growth hormone ACTH and ADH.
GENITAL SYSTEM
• Flaccid paralysis of nervi erigentes and engorged penis
THERMO REGULATION
• Vasodilatation causes heat loss at site of block causing shivering which is
compensated by vasoconstriction
RENAL FUNCTION-
• Neuraxial blockade has little effect on the blood flow to the renal system.
Autoregulation maintains adequate blood flow to the kidneys as long as perfusion
pressure is maintained.
• Neuraxial blockade effectively blocks sympathetic and parasympathetic control of
the bladder at the lumbar and sacral levels.
•Urinary retention can occur due to the loss of autonomic bladder control. Detrusor
function of the bladder is blocked by local anesthetics.

46. SUBARACHNOID BLOCK IN NEONATES, INFANTS AND CHILDREN
SAB in children does not produce haemodynamic instability because:
1.Small venous capacitance of the lower extremities less prone to venodilation.
2.Immature sympathetic autonomic system
INDICATION----Lower abdominal, pelvic and lower limb surgeries
DOSAGE –
Hyperbaric 0.5% bupivacaine for T4 level
1mg/kg bupivacaine-Premature infant
0.8mg/kg – full term
0.5mg/kg – small children
Complication
• Technically difficult
• High failure rate

47. SPINALANAESTHESIA CAN BE SAID TO HAVE
THE FOLLOWING ADVANTAGES OVER
EPIDURAL
1. It is easier.
2. It is quicker
3. It provides slightly better relaxation of the abdomen
4. The danger of toxicity due to the drugs is negligible
because of smaller doses of the drugs used.

48. ADVANTAGES OF SPINALANAESTHESIA
OVER GENERALANAESTHESIA
1. Cheap
2. Obviates the need for general anaesthesia, which may be
problematic in some patients.
3. Spontaneous respiration, with good abdominal relaxation
(useful in patients with respiratory disease like COPD)
4. Avoids need for intubation where this is likely to be difficult.
5. Reduction of surgical hemorrhage, e.g. at prostatectomy.
6. Decreased incidence of thromboembolism due to early
ambulation

49. DISADVANTAGES OF SPINAL OVER
GENERAL ANAESTHESIA
•Discomfort, especially for long operations.
•Discomfort eliciting paraesthesia.
•Contraindicated in confused patient.
•Profound cardiovascular effects.
•Leg weakness and urinary retention.
•Toxicity with high serum levels of anaesthetic
drugs or accidental i.v. injection.
•Poor communication of intentions if deaf
patient

50. EPIDURALANESTHESIA

51. Epidural Anesthesia
• A Neuraxial technique that offers a wide range of applications.
• An Epidural block can be performed at the Lumbar, Thoracic,
Cervical and Caudal level
• Wide use of applications; Operative anesthesia, Obstetric
Anesthesia & Analgesia, Postop pain control and Chronic Pain
Management
• It can be used as a “Single Shot” or with a catheter that allows
intermittent boluses or a Continuous Infusion

52. Anatomy
• The Epidural space surrounds the Dura Mater posteriorly,
laterally and anteriorly
• Nerve roots travel in this space as they exit the spinal cord
laterally
• They then exit the foramen and travel peripherally to become
peripheral nerves carrying both afferent and efferent pathways

54. 54
Boundaries Contents
• Cranially by foramen magnum.
• Caudally by sacrococcygeal ligament.
(sacral hiatus)
• Anteriorly by posterior longitudinal
ligament
• Laterally by vertebral pedicles &
intervertebral foramina.
• Posteriorly by ligamentum flavum &
vertebral lamina.
• Nerve roots
• Blood vessels-
Batson’s venous
plexus
• Lymphatic
• Fat
• Areolar tissue

55. Physiology
 Local anesthetics or other solutions injected into the epidural
space (steroids, narcotics) spread anatomically
 Horizontal spread to the region of the Dural cuffs with
diffusion into the CSF and leakage through the intervertebral
foramen into paravertebral spaces
 Longitudinal spread is preferentially cephalad in direction.

56. Physiology
 Possible sites of anesthetic action include:
1 Intradural spinal roots
2 Dorsal and Ventral spinal roots
3 Dorsal root ganglia
4 The Spinal Cord
5 The Brain itself (by diffusion)
6 Paravertebral nerve roots

57. Physiology
 Initial blockade is PROBABLY a result of anesthetic blockade at the
spinal roots within the Dural sleeves
 The Dural Cuffs or Sleeves have a proliferation of arachnoid villi
and granulation tissue that effectively reduce the THICKNESS of
the dura mater facilitating rapid diffusion of the LA from the
Epidural space, through the Dura and into the CSF surrounding the
nerve roots
 Then the local anesthetic diffuses into the nerve root itself,
producing anesthesia to that particular dermatome

58. 58
Difference between spinal and epidural
anesthesia
Spinal anesthesia Epidural Anesthesia
Level: below L1/L2, where the spinal cord ends Level: at any level of the vertebral column.
Injection: subarachnoid space i.e. puncture of
the Dura mater
Injection: epidural space (between Ligamentum
flavum and dura mater) i.e without puncture of
the dura mater
Identification of the subarachnoid space: When
CSF appears
Identification of the Epidural space: Using the
Loss of Resistance technique.
Dose: 2.5- 3.5 ml bupivacaine 0.5% heavy Dose: 15- 20 ml bupivacaine 0.5%
Onset of action: rapid (2-5 min) Onset of action: slow (15-20 min)
Density of block: more dense Density of block: less dense
Hypotension: rapid Hypotension: slow
Headache: is a probably complication Headache: is not a probable.

59. 59
Advantage
 Minimise effect of surgery on Cardiopulmonary reserve.
 patient with compromised Respiratory system
 Morbid obesity
 COPD
 Elderly
 Earlier mobilization
 Decreased chances of DVTE

60. 60
Effective analgesia without taking systemic opioids.(
analgesics are given through catheter)
Reduce the incidence of Myocardial infarction
Surgery induced Stress response is decreased
Blood loss is less and
Everything can be regulated and changed by:
1) Choice of drug
2) Concentration of LA
3) Dosage
4) Level of Injection

61. 61
Disadvantage
• Risk of block failure
• Onset is slower
• Risk of infection
• Epidural hematoma
• Continous epidural catheter should not be used in the ward
if monitoring is not proper.

62. 62
Indications
• Epidural anesthesia with or without sedation has been used as the sole
anaesthetic or as an adjunct to general anesthesia (reduces patient’s
requirement for opioid analgesics)
• Orthopaedic surgery : Major hip/knee surgery, pelvic fractures
• Obstetrics : Caesarean section, labour analgesia
• Gynaecologic surgery : Procedures involving female pelvic organs
• Urologic surgery : Prostate, bladder procedures
• General surgery : Upper and lower abdominal procedures
• Paediatric surgery : Penile procedures, inguinal hernia repair, anal
surgery, orthopaedic procedures on the feet; supplement to GA,
postoperative pain relief.

63. 63
• Vascular surgery : Vascular reconstruction of the lower limb vessels,
amputations involving the lower extremities.
• Thoracic surgery : Postoperative analgesia, combination with GA to
reduce GA requirements.
• Diagnosis and management of chronic pain : Chronic benign pain-
Cervical & lumbar radiculopathy, vertebral compression fracture ,
degenerative disc disease, peripheral neuropathy, low back pain,
pelvic pain syndrome.
• Cancer related pain- pain secondary to face, neck, shoulder, genital,
pelvic, perineal etc .malignancy. & chemotherapy related peripheral
neuropathy.

64. 64
Contraindications
• Patient refusal
• Infection at site
• Raised ICP
• Severe AS, severe MS
• Allergy to LA drugs
• Severe
hypovolaemia/shock
• Coagulation disorder
• Pre-existing neurological
disease
• Demyelinating
disease(Multiple sclerosis)
• Abnormalities of spine
• Uncooperative patient

65. 65
Physiologic Effects of Epidural Block
• Most physiologic effects of epidural block stem from Autonomic
Blockade due to action of LA on autonomic nerve fibres of the
spinal cord.
• The actions mostly pertain to either Blockage of Sympathetic
outflow or Unopposed dominance of Parasympathetic outflow.

66. Epidural needle
 Epidural needles have larger diameter than Spinal needle.
 Typically sized of 16-19 gauge.
1 Tuohy & Hustead needle –with gently curve of 15-30°
degree.
2 Crawford needle- with straight tip.
66

67. 67
Epidural needle
 Epidural needles have larger diameter than Spinal
needle.
 Typically sized of 16-19 gauge.
1 Tuohy & Hustead needle –with curved tip
2 Crawford needle- with straight tip

68. Common LA Used for Epidural Anesthesia
 Bupivacaine:
0.125-0.25% for analgesia
0.5% for anesthesia
 Ropivacaine:
0.1 - 0.2% for analgesia
0.5-1% for anesthesia
 Lidocaine:
2% for anesthesia
 levobupivacaine:
0.5 -0.75% for anesthesia
0.125-0.25% for analgesia
68

69. 69
Pharmacology related to Epidural Anesthesia
Anaesthetic administered epidurally 20-30 ml volume.
Drug Conc Onset(min) Duration
Plain
Duration with
Epinephrine
Lidocaine 2% 15 80-120 120-180
Bupivacaine 0.5-0.75% 20 165-225 180-240
Levobupivacaine 0.5-0.75% 15-20 150-225 150-240
Ropivacaine 0.75%-1% 15-20 140-180 150-200
Mepivacaine 2% 15 90-140 140-200

70. 70
Some Common Procedural Preferences
Labour
analgesia
LSCS Hip/Knee
surgery
Laparotom
y under GA
Thoracotomy/
fractured ribs
Level of
insertion
L2-L4 L2-L4 L2-L4 T8-T10 At relevant
interspace
usally
Height of
block
T8-T9 T6-T7 T10 Upper
abdo.T7-
T8,Lower
abdo.T10
Relevant area
Density of
block
Sensory &
Minimal
motor
Motor &
Sensory
Motor &
Sensory
Sensory &
Minimal
Motor
Sensory &
minimal motor

71. 71
Labour
Analgesia
LSCS Hip/Knee
surgery
Laparotomy
under GA
Thoracotomy/
Fractured ribs
Choice of
local
anaesthetic
0.1%-0.25%
Bupivacaine
Lignocaine2
% +
Bupivacaine0.
5%
Bupivacaine
0.5%
0.25%-0.5%
Bupivacain
0.25%-0.5%
Bupivacaine in
theatre or
establish block
Infusion Bupivacaine.1
%+ Fentanyl
2mcg/ml
Post op
Bupivacaine
0.166%+Dia
morphine
.1mg/ml
Not usually
necessary
Post op
Bupivacain0.
166%+Diam
orphine
0.1mg/ml
Post op
Bupivacaine
0.166%+Diam
orphine
.1mg/ml
Rate of
infusion
0-12 ml/hr 0-8mls/hr -- 0-12mls/hr 0-8mls/hr

72. 72
Performing the procedure
 Position of patient- Careful attention to the patient’s position is
essential to successful placement of the epidural needle and
catheter.
Depending on the patient’s medical status, weight, and ability to
cooperate, the sitting or lateral decubitus position can be used.
Easier in sitting position.
 Approach - Four common approaches to the epidural space are
possible:
1. Midline,
2. Paramedian,
3. Taylor (modified paramedian),
4. Caudal

73. Technique
• The most commonly performed Epidural is a Lumbar Epidural,
followed by a Caudal, then Thoracic and finally Cervical.
• Today most high thoracic and cervical epidurals are performed under
flouroscopic guidance by pain specialists as it takes a greater level of
skill to successfully perform those procedures.

74. Technique

76. 76
• Needle angulation required to accomplish epidural blockade in the
high thoracic/low thoracic/lumbar regions.
A: High thoracic region. B: Low thoracic region. C: Lumbar region.

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Locating the Epidural space
• All aseptic precaution is taken.
• Skin is infiltrated with local anesthetic in to desired space(identified).
• Needle is advanced slowly, feel of increase resistance.
• 3 methods are used to identify Epidural space-
 Loss of resistance (to with air or saline):-As needle
reaches Epidural space Loss of Resistance is felt less 2 yr old air
LORS Vs LORA:
• LORA is associated with nerve root compression, pneumocephalus and
greater incidence of incomplete analgesia, paresthesia and venous air
embolism.
• LORS is associate with reduces incidence of dural puncture in adult, while
in pediatric patients, dural puncture incidence are more.
• LORA is safer than LORS in children less than 2 yrs old.

78.  Hanging drop method:-As needle reaches Epidural space
Hanging drop is sucked in d/t negative pressure.
 In cervical region, negative pressure poorly reliable and only
useful in sitting position.
 The negative intra-thoracic pressure may influence the pressure
in epidural spaces in thoracic region and should be maximal
during inspiration.
Ultrasonography / Fluoroscopy

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Hanging Drop Technique

81. Single –end hole catheter Spring wire-reinforced
catheter
Closed tip, multiple-side
hole catheter
Types of epidural catheter

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Catheter placement
• The catheter is made of a flexible, calibrated, durable,
radiopaque plastic .
• Typically, 19-or 20- gauge catheter is introduced through 17-or
18- gauge epidural needle.
• Catheter is threaded through needle after placing in space.
• Needle is withdrawn over the catheter.
• 4-6 cms catheter remain in epidural space. Threading more
catheter may increase the likelihood of catheter malposition.
• Catheter is firmly secured to skin with surgical tape.

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Epidural catheter placement

84. 84
Continuous infusion

85. CAUTION
 NEVER pull the catheter back through the needle once it has
been inserted
 It is possible to catch the catheter on the needle tip and shear or
cut the tip off
 Then it becomes a permanent new addition to the epidural space
and will be there for the rest of the patient’s life!!!!

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Epidural Dosing
As a general guideline,
1. 1–2 mL per segment in a lumbar epidural,
2. 0.7 mL per segment in a thoracic epidural, and
3. 3 mL per segment for a sacral/caudal epidural
is used as an initial loading dose.
• Test Dose
• Incremental Dosing
• Aspiration to check for blood or CSF before each dose.
• After the initial loading dose, one quarter to one third of the amount
can be administered 10–15 min later to intensify the sensory block.
The overall level of the block will not be significantly increased
with this method.

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Test Dose
• The purpose of the “test dose” is to make sure that the catheter is not in
the subarachnoid, intravascular, or subdural space.
• The classic test dose combines 3 mL of 1.5% lidocaine with 15 mcg of
epinephrine.
• The intrathecal injection of 45 mg of lidocaine will produce a
significant motor block consistent with spinal anesthesia.
• A change in heart rate of 20% or greater is an indication of
intravascular injection warranting the removal and replacement of the
catheter.
• If the heart rate does not increase by 20% or greater, or if a significant
motor block does not develop within 5 min of administering the test
dose, it is considered negative.
• False-ve if pt is on β blocker, false +ve in pregnancy if coincides with
labour pain.

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Factors affecting Epidural Anesthesia
 Site of injection-
 Lumbar- spread cranially more than caudally
 Thoracic- spread evenly from site of injection
 Upper thoracic & lower cervical fibers are comparatively resistant
d/t larger size of nerve roots-requires larger dose of LA.
 Thoracic epidural space is smaller, require lower volume of drug.
 Dose- 1-2 ml /segment.
 Depends on volume & concentration of drug. Higher conc.
produces a profound motor and sensory block, whereas low conc. a
selective sensory block.

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 Age - as patient age increases reduced size of intervertebral
foramina decreased epidural space size and compliance.
Decreased epidural fat necessitates decrease of dose in elderly.
 Weight - There is little correlation between the spread of analgesia
and the weight of the patient.
In morbidly obese patients, there may be compression of the
epidural space secondarily to increased intra-abdominal pressure,
creating a higher block for a given dose of local anesthetic.

90. 90
 Height - The correlation with height is usually not clinically significant.
Ht. <5 ft 2 inch, reduce the dose to 1 ml/segment to be blocked.
Bromage dosing regime - Increasing the dose of local anaesthetic by 0.1 mL
per segment for each 2 inch over 5 ft of height.
 Addition of Vasoconstrictors - Epinephrine 5 mcg/ml (1:200000) is
most commonly added.
 Prolongs duration of action by reducing the vascular absorption of drug.

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 Posture-
Block Ht. - Whether the patient is sitting or in the lateral position,
there is no significant difference in block height. This is explained by
the fact that gravity and soln. baricity are not intimately related to
block spread.
Onset, Duration & Density - slightly faster on the dependent side
when the epidural in placed with the patient in the lateral position
 Pregnancy- Increased sensitivity to regional anesthetics leads to
faster onset time.
Engorgement of Epidural veins from caval compression leads to
increased incidence of blood vessel puncture during procedure.

92. Complications
Drug Related Complications-
• CNS toxicity
• CVS toxicity
Procedure Related Complications-
• Minor Back Pain
• Postdural Puncture Headache
• Subarachnoid Injection/High or Total Spinal
• Major Subdural Injection
• Sheering of catheter
Neurologic Complications-
• Spinal nerve neuropathy
• Transient neurological symptoms
• Anterior spinal artery syndrome
• Adhesive arachnoiditis
• Epidural hematoma
• Epidural abscess

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• Postdural Puncture Headache : Due to inadvertent dural
puncture.
TOC – Epidural blood patch.
 Cosyntropin, ( ACTH analogue) .
 Postulated mechanisms include increased CSF production via sodium
channels; aldosterone mediated salt and water retention, and possibly
increased β endorphin output.
 One of the trials used 1 mg of cosyntropin for the prophylaxis of PDPH.
It showed more than 50% reduction in the incidence of PDPH
 Mannitol-
 It acts “ acute increases in blood osmolality decreases brain water
content (mainly in healthy brain tissue with intact blood brain
barrier)decrease brain bulk, intracranial pressure, increased intracranial
compliances.” decrease brain bulk, causes brain re-float in contracted
CSF volume.
 It believe that re-floatation of brain is an important factor to alleviate
PDPH with other factors.

94. 94
Neuraxial block in setting of anticoagulant and
antiplatelet drugs
(recommended by American Society of Regional Anesthesia)
• Neuraxial block and indwelling catheters are safe in patients on
aspirin , NSAID’s & cox-2 inhibitors.
• Discontinue clopidogrel for 7 days ,ticlopidine for 14 days
,abciximab for 24-48 hrs ,tirofiban & eptifibatide for 4-8 hrs
before technique.
• Wait at least 12 hrs before last thromboprophylaxis dose of
LMWH and 24 hrs after last full dose
• When LMWH is begun post-op first dose should be withheld for
at least 24 hrs if using a twice daily dosing regimen and 6-8 hrs
if using once daily dosing regimen

95. 95
• An indwelling epidural catheter should not be removed until 12 hrs
after the last prophylaxis dose of LMWH, and the next dose should
be administered no sooner than 2 hrs after catheter removal
• If a single daily thromboprophylaxis dose of LMWH is administered,
then indwelling catheters may be maintained postoperatively. But the
concurrent use of twice daily or therapeutic LMWH and an
indwelling epidural catheter is not recommended.
• The LMWH dose is delayed for 24 hr if the patient experienced
excessive trauma during attempted epidural or spinal anesthesia.
• Neuraxial blocks should not be performed in patients chronically
taking warfarin unless the warfarin is stopped and the INR is <1.5
• Neuraxial catheters should be removed only when the INR is <1.5

96. 96
Combined spinal-epidural anesthesia
• Introduced in 1939 when Soresi et al presented a paper on usage of
CSE in 200 patients.
• Technique combining both spinal and epidural.
 Spinal component gives rapid onset and dense predictable block.
 Epidural catheter is used to supplement insufficient subarachnoid
block (to increase height or duration of block) and also to provide
long-lasting analgesia.
 reduces the incidence of several potential problems associated with
the conventional epidural technique, including incomplete (patchy)
blockade, motor block, and poor sacral spread.

97. 97
 The sequential CSE technique may be particularly advantageous in
high-risk patients, such as in those with cardiac disease, when slower
onset of sympathetic blockade is desirable.
• Two approaches are mostly used:
1. Needle Through Needle
2. Needle Below Needle.

98. THANK YOU