Spinal anaesthesia in detail with complications

1. SPINAL
ANAESTHESIA
PRESENTED BY
DR. SHAILENDRA SATPUTE

2. BRIEF HISTORY OF SPINAL ANAESTHESIA
 CSF DISCOVERED ---- by Domenico Catugno 1764
 CSF CIRCULATION----by F . Magendie 1825
 FIRST SPINAL ANALGESIA--- by J Leonard Corning 1885
 FIRST PLANNED SPINAL ANAESTHESIA ON HUMAN--- by
August Bier in 1891
 The epidural space was first described by Corning in 1901, and Fidel
Pages first used epidural anaesthesia in humans in 1921.

3. ANATOMY
•cervical vertebrae (7)
•thoracic vertebrae (12)
•lumbar vertebrae (5)
•sacral vertebrae (5)
•coccygeal vertebrae (4 )

4. Spinal cord
• The adult spinal cord measures approximately 41 to 48
cm in length.
• Weight of spinal cord is between 24 to 36 gm.
• It is about 1 cm in diameter with cervical and
lumbosacral expansion.
• The spinal cord extends caudally from the brain. Its upper
end is continous with brain (medulla oblongata)

5. The spinal cord usually ends at the level of L1
in adults and L3 in children.
Dural puncture above these levels is associated
with a slight risk of damaging the spinal
cord and is best avoided.
An important landmark to remember is that a
line joining the top of the iliac crests is at
L4 to L4/5

6. Surface anatomy
• Spinous processes
are palpable over the
spine and help define
the midline
• In cervical area First
palpable spinous
process is C2
• Most prominent
spinous process is C7

7. Surface anatomy
• Spinous process of
T7 – inferior angle of
scapula
• Tuffier’s line –
body of
L4 or L4-L5
interspace

8. DERMATOMES
A dermatome is an area of skin innervated by
sensory fibers from a single spinal nerve

9. Cerebrospinal fluid (CSF)
• The CSF is the clear
watery fluid contained
within the cerebral
ventricles and the
subarachnoid space.
• The total volume of CSF
is about 100-160 ml
adult humans and it is
produced at a rate of 20 to
25ml/hr

10. • CSF is an ultra filtrate formed by active process
from the choroid plexus of the lateral
ventricles
• The epidymal cells of pia covering the blood
vessels play the secretary role
• At 500-600ml of CSF is formed per day

11. • About 20-25 ml of CSF is present in the
ventricles
• 90 ml of the CSF in reservoirs in the brain
• 25-30 ml of CSF occupy the sub arachnoid space
• It is produced at a rate of 0.4ml/min
• It is around 25ml/hr

12. •About 4/5th of fluid is reabsorbed via the
arachnoid villi.
•The remaining 1/5th of the CSF is absorbed
via similar spinal arachnoid villi or escapes
along the nerve sheaths in to the lymphatics.

13. • The specific gravity of CSF is 1.003-1.009
• Its PH is 7.4 - 7.6
• Na - 140-150 meq/L
• Chloride - 120-130
mEq/L
• Bicarbonate - 25-30
meq/L
• Proteins – 15-45 mg/dl
• Glucose – 50-80 mg/dl

14. DERMATOMAL LEVELS OF SPINAL ANESTHESIA FOR COMMON
SURGICAL PROCEDURES
Procedure Dermatomal Level
Upper abdominal surgery T4
Intestinal, gynecologic, and
urologic surgery Transurethral
resection of the prostate
T6
Vaginal delivery of a fetus, and hip
surgery
T10
Thigh surgery and lower leg
amputations
L1
Foot and ankle surgery L2
Perineal and anal surgery S2 to S5 (saddle block)

15. PHYSIOLOGICAL EFFECTS OF NEURAXIAL
BLOCKADE
CARDIOVASCULAR EFFECTS:
•Vasomotor tone determined by sympathetic fibers
arising from T5 to L1 innervating arterial & venous
smooth muscle.
•A ↓ in blood pressure that may be accompanied by
↓ in heart rate.
•With high sympathetic block, sympathetic cardiac
accelerator fibers arising at T1-T4 are blocked, leading to
↓ cardiac contractility.
•Bezold-Jarisch reflex has been implicated as a cause of
bradycardia, hypotension and cardiovascular collapse
after central neuraxial anaesthesia, in particular spinal
anaesthesia.

16. Cardiovascular effects…..
 Arterial and venous dilatation both occur
 Arterial dilatation may lead to increased aft
erload and CO
 Venous dilatation also occur which leads to
decreased preload and CO
 Bt as 75% vascular supply is venous; result
ant effect is decrease in preload and CO
 A decrease in MAP is anticipated after SAB;
a reduction of 20% MAP can be tolerated

17. PULMONARY EFFECTS:
 Even with high thoracic levels, tidal volume is
unchanged.
 A small decrease in vital capacity due to paralysis of
abdominal muscles (accessory muscles of
respiration) necessary for forced exhalation & not
due to decrease in phrenic nerve or diaphragmatic
function.
 Effective coughing & clearing of secretions may get
affected with higher levels of block.
 Rare respiratory arrest associated with spinal
anaesthesia due to hypoperfusion of respiratory
centers in brain stem.

18. GASTROINTESTINAL FUNCTION:
 Nausea and vomiting in upto 20% patients due
to gastrointestinal hyperperistalsis caused by
unopposed parasympathetic(vagal) activity.
 Vagal tone dominance results in small
contracted gut with active peristalsis & can
provide excellent operative conditions for some
laproscopic procedures when used as an
adjunct to GA.
 Hepatic blood flow will ↓ with reductions in
mean arterial pressure.

19. RENAL FUNCTION:
 Renal function has a wide physiological reserve. ↓
in renal blood flow is of little physiological
importance.
 Urinary bladder supplied by S2-S4 usually gets
blocked leading to decreased bladder tone and
retention of urine
 Neuraxial blocks are a frequent cause of urinary
retention which delays discharge of outpatients &
necessitates bladder catheterization in inpatients.

20. Indications
Surgeries of lower limbs, perineum, pelvis, abdomen
It is ideal in
•Renal failure – onset is rapid, spread is greater by
two or three segments, duration is shorter
•Cardiac disease
•Liver disease
•Obstetric anaesthesia

21. Indications
• Immunosuppressed patients – does not impair cell
mediated immunity
• Elderly patients
• Diabetes mellitus

22. CONTRAINDICATIONS
ABSOLUTE
1. patients refusal
2.coagulopathy
3.infection at local site
4. severe hypovolemia
5. increased ICT
6. allergy to drugs
7. Shock
8. sever AS or MS
RELATIVE
1.uncoperative pt
2.preexisting neurological
deficits
3.demyelinating lesions
4.severe spinal deformity
5.infection at site remote
from insertion
¡sepsis

23. SEQUENCE OF ONSET
 Principal site of action is the nerve root.
 Sequence of onset depends on conc. of LA achieved, duration of
contact, size & myelination of nerve fibers.
CLINICALLY OBSERVED SEQUENCE
• Sympathetic nervous system fibers (B fibers:
vasodilation, skin temp ↑)
2. Temperature & pain conduction (A& C fibers)
3. Proprioception & touch (AȖ & Aȕ fibers)
• Motor function (A fibers)

24. DOSAGE AND ACTIONS OF COMMONLY USED SPINAL ANESTHETIC
DRUGS
Medication Preparation Dose
Lower
Limbs
Dose Lower
Abdomen
Dose
Upper Abdomen
Procaine 10% Solution 75 mg 125 mg 200 mg
Lidocaine 5% Solution in 7.5%
dextrose
25-50 mg 50-75 mg 75-100 mg
Tetracaine 1% Solution in 10% glucose
or as niphanoid crystals
4-8 mg 10-12 mg 10-16 mg
Bupivacaine 0.5-0.75% Isobaric
Solution
0.5-0.75% Hyperbaric
Solution in 8.25% Dextrose
Hypobaric Solution
4-10 mg 12-14 mg 12-18 mg
Ropivacaine 0.2—1% solution 8-12mg 12-16 16-18

25. Dosage of drug used
 Hyperbaric Bupivaciane-
 According to weight
 0-5kg – 0.5ml/kg
 5-15kg – 0.4ml/kg
 >15kgs – 0.3ml/kg
 According to height(can be used in
pregnant females)-0.06ml/cm of hei
ght

26. Pediatric drug dosing
 Pediatric drug dosage can be calcula
ted by using
 Young’s formula-
 Child dose=age/(age+12) multiplied
by average adult dose

27. FACTORS AFFECTING THE LEVEL OF SPINAL
ANESTHESIA
MOST IMPORTANT FACTORS
Baricity of the drug
Position of the patient
Drug dosage
Site of injection
OTHER FACTORS
Age
Csf
Curvature of Spine
Intraabdominal Pressure
Needle direction
Patient Height
Pregnancy
Weight of pt

28. PROCEDURE PREPERATION
 Remove your jewellery/watches
 Wash your hands
 I.V access/fluids bolus if needed
 Emergency drugs /equipment
 Position
 Sedation if needed
 Monitoring
NIBP/SPO2/ECG
• Verbal contact with pt

29.  POSITIONING
1. Sitting
2. Lateral
3. Prone
 TECHNIQUES FOR SPINAL
1. Midline
2. Paramedian
3. Taylor approach
The structures that will be passed in spinal :
Skin , subcutaneous tissue, supraspinous ligament ,
interspinous ligament , lagementum flavum , dura
mater , subdural space , arachnoid
matter,subarachnoid space in midline approach

30. Positions
• Lateral flexed position
-most commonly used
-back parallel to edge of
table
-hips and knees flexed,
neck and shoulder flexed
towards knees
-nose to knees

31. Positions
• Sitting position
-for saddle block
anaesthesia
-obese patients,
pregnant patients,
patients with
abnormal spinal
curvatures

32. Positions
• Sitting position
-patient should sit on the
table with knees resting
on the edge, legs
hanging over the side
and feet supported by a
stool below

33. Positions
• Prone position
- suitable for hypobaric
techniques
-patient should be in
prone position with OT
table flexed under his
flanks, just above the
iliac crests

34. Technique
• Hands and lower forearms scrubbed for at least 3
minutes
• Sterile gloves should be applied
• A large area of L-S spine from lower border of scapula to
iliac crests should be painted using antiseptic solution
• Excess antiseptics removed after waiting for sufficient
time for the antiseptic to act

35. Technique
• Area is draped – view of T12 to S1 and laterally of
quadratus lumboram muscles
• Selection of space – tuffier’s line AKA Jacoby’s line
OR intercristal line is line drawn across the highest
points of iliac crests
• Raise a skin wheal with 2ml of 2% lignocaine solution
after negative aspiration for blood

36. Technique
Insert an introducer in the midline
Uses -prevents deflection of spinal
needle
-fine gauge needles can be used
-decreases incidence of
postpuncture headache
-decreases infections
-avoids skin fragments from
entering

37. Technique
• Spinal needle is inserted with the stylet through the
introducer
• Needle should be inserted in the midline and directed
cranially at an angle of less than 50 degrees to the
longitudinal axis of the vertebral column
Bevel of the spinal needle should be kept parallel to the
longitudinal axis of the spine
Loss of resistances can be felt after puncturing
ligamentum flavum (1st resistance) and the duramater
(2nd resistance).

38. Layers traversed by the spinal needle
(posterior to anterior)
•
•
•
Skin
Subcutaneous tissue
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Duramater
Sub dural space
Arachnoidmater
Subarachnoid space
•
•
•
•

39. Technique
• Remove stylet to observe free flow of CSF
• Attach 5 ml Luer Lok syringe containing anaesthetic
mixture to the spinal needle
• Stabilize the spinal needle and attach the syringe by
grasping the hub of spinal needle with thumb and index
finger while propping the remaining fingers against the
patient’s back to provide support (bromage grip)

40. Technique
• Inject at the rate of 0.2ml/sec
• Aspirate small amount of spinal fluid to determine if
the needle is still placed properly
• Remove spinal needle and introducer quickly and
simultaneously

41. Technique
Paramedian approach
• 1-1.5 cm lateral to
midline
Spinal needle is
inserted at an angle
of 25 degrees with the
midline and without
deviation cephalad or
caudad
•

42. Technique
Paramedian approach
•Needle lies lateral to supraspinous and interspinous
ligaments bypassing them and penetrates ligamentum
flavum and duramater in the midline
•It pierces skin,subcutaneous tissue,lumbar
aponeurosis,ligamentum flavum,dura and arachnoid
mater.
•Useful in arthritis , deformed spine,those who cannot be
positioned properly,kyphoscoliosis.

43. Taylor
technique
A 12 cm spinal needle is
inserted 1 cm medially and
1 cm above the lowest
prominence of posterior
superior iliac spine
Needle is directed
upwards medially and
forwards at an angle of 50
degrees

44. Technique
Taylor technique Uses :
•Spinal fusion
•Arthritic spine
•Opisthotonus
•Skin infection in lumbar region

45. SPINAL NEEDLES

46. Spinal needles
Three parts
–Hub
–Canula
–Stylet
•Point of the canula is beveled and has a sharp edge
•Lumenal sizes : 18 gauge to 30 gauge
•Length : 3.5 to 4 inches
•Colour coding:white (16Gz) pink
(18Gz),ivory/cream(19Gz),yellow (20Gz),green
(21Gz),black (22Gz),blue (23 Gz),orange (25Gz),brown
(26Gz),

47. Spinal needles
• Quincke Babcock needle
• Medium length
• Sharp edges
• Cutting bevel
• Hub with leur lock connector
• End injection.

48. Spinal needles
• Whitacre needle
• Small hub
• Pencil point type of
bevel compeletely
rounded
• Non-cutting and solid
• Side opening 2mm
proximal to tip

49. Spinal needles
• Sprotte needle
• Side injection
needle with long
opening
• Causes more
vigorous flow of
CSF
• Failed block when
only distal part of
opening is in SA
space

50. Spinal needles
• Pitkin needle
• Small hub
• Short, sharp
point bevel with
cutting edges

51. Spinal needles
• Touhy needle
• Leur lock connector
• Tip curved
• Bevel is medium
length
• Cutting edges
• Bevel of the point is
designated as “Huber
point”

52. Spinal needles
• Greene needle
• Small hub
• Medium bevel
• Rounded,non
cutting edges of the
bevel
• End injection

53. • Local anaesthetic solution injected into the
subarachnoid space blocks conduction of impulses
along all nerves with which it comes in contact,
although some nerves are more easily blocked than
others.
• There are three classes of nerve: motor, sensory and
autonomic.
• Stimulation of the motor nerves causes muscles to
contract and when they are blocked, muscle paralysis
results.
Mechanism of action

54. Mechanism of action
 Sensory nerves transmit sensations such as touch
and pain to the spinal cord and from there to the
brain, whilst autonomic nerves control the calibre of
blood vessels, heart rate, gut contraction.
 Generally, autonomic and sensory fibres are
blocked before motor fibres. This has several
important consequences.

55. Mechanism of action
• For example, vasodilation and a drop in blood
pressure may occur when the autonomic fibres are
blocked.
Practical implications of physiological
changes. The patient should be well hydrated
before the local anaesthetic is injected and should
have an intravenous infusion in place so that further
fluids or vasoconstrictors can be given if
hypotension occurs.
•

56. Mechanism of action of local
anaesthetics on nerve conduction
• Interacts with the receptor situated within the voltage
sensitive sodium channel and raises the threshold of
channel opening
• Decreases the entry of sodium ions during upstroke of
action potential

57. Mechanism ……..
• Local depolarization fails to reach the threshold
potential and conduction block ensues
• Onset time of blockade is related to the pKa of the LA
• Lower pKa – fast acting

58. Adjuvants used
Opioids
•Addition of opioids improves analgesic quality, prolongs
sensory block, reduces local anaesthetic requirements,
reduces duration of motor blockade and improves
haemodynamic stability
•Fentanyl – 12.5 mcg to 25mcg
•Sufentanyl – 2.5 – 5 mcg
•Diamorphine – 0.3 mg
•Morphine – 0.1 – 0.2 mg

59. Adjuvants used
•Epinephrine- 0.2 mg; Decreases blood flow
• Clonidine- 10-15mcg; Prolongs duration of
sensory analgesia
• Neostigmine- 5-100mcg; inhibits the
breakdown of acetylcholine

60. Baricity
Density of a solution in relation to density of CSF
•Hypobaric solutions : raise against gravity
•Isobaric solutions : tend to remain in the same sight
where they are injected
•Hyperbaric solutions : tend to follow gravity

61. Factors affecting block height
(postulated)
• Patient characteristics
– Age
– Height
– Weight
– Gender
– Intra abdominal pressure
– Anatomic configuration of spinal column
– Position

62. Factors affecting block height
(postulated)
• Technique of injection
– Site of injection
– Direction of injection
– Direction of the bevel
– Use of barbotage
– Rate of injection

63. Factors affecting block height
(postulated)
 Characteristics of anaesthetic solution
 Density
 Amount
 Concentration
 Temperature
 Volume
 Vasoconstrictors

64. Factors affecting block height
(postulated)
• Characteristics of spinal fluid
– Volume
– Pressure
– Density

65. Factors influencing block height
Controllable factors
•Dose ( volume x concentration)
•Site of injection
•Baricity of local anaesthetic solution
•Posture of patient

66. Factors influencing block height
Factors not controllable
•Volume of CSF
•Density of CSF

67. Sequence of nerve modality block
1. Vasomotor block – dilatation of cutaneous
vessels and increased cutaneous blood flow
2. Block of cold temperature fibres
3. Sensation of warmth felt by the patient
4. Temperature discrimination is lost
5. Los of slow pain

68. 6. Loss of fast pain
7. Tactile sensation is lost
8. Motor paralysis
9. Pressure sense abolished
10. Proprioception and joint sense is lost
Sequence of nerve modality block

69. Testing for levels of block
Sympathetic block
•Skin temperature sensation
•Changes in the skin temperature

70. Testing for levels of block
Sensory level
•Pin prick using sterile needle
•Loss of touch is two dermatomes lower
than pin prick

71. Testing for levels of block
Motor block
•Modified Bromage scale of onset of motor block

72. Spinal anaesthesia in pregnancy
Decreased dose requirement due to
•Mechanical factor : compression of IVC causes
shunting of blood to the venous plexus in the
vertebral canal
• Decreased vertebral canal space and CSF volume
•Hormonal factor – higher progesterone levels

73. COMPLICATIONS/SIDE EFFECTS OF NEURAXIAL
ANESTHESIA
 Systemic toxicity
 Hypotension
 Postdural Puncture Headache
 High Spinal Anesthesia
 Total spinal anaesthesia
 Neurological complications
 Arachnoiditis / Meningitis
 Spinal / Epidural Hematoma
Formation
 Epidural Abscess
 Backache
 Urinary retension
 Pruritus

75. POSTDURAL PUNCTURE HEADACHE
 ONSET= 12—72 hrs
 it is postural and it is often fronto--occipital associated
with stiff neck , nausea, vomiting , dizziness and
photophobia.
 CAUSE---loss of CSF at a faster rate than it can be
produced causing traction on the structures supporting
brain, particularly dura and tentorium.
 INCIDENCE---25%
 FACTORS---that increase the risk are young
age,female,pregnancy,large guage needles and multiple
punctures
 It is aggravated by sitting or standing and decreased or
relieved by lying down flat.
 TREATMENT----- conservative t/t involves recumbent
position, analgesics, i.v or oral fluids and caffeine.
29

77. EPIDURAL BLOOD PATCH
 The epidural blood patch
consists of injecting 5-20 mLs
of autologous blood into the
epidural space, in the region
of the suspected dural 'hole.'
 Autologous blood is typically
drawn in a sterile fashion, and
then injected as a bolus into
the epidural space.
 In 90% of cases, the response
is positive and immediate.
Subsequently, long-term relief
of PDPH occurs in the
majority of cases

78. HIGH NEURAL BLOCKADE ,HIGH
SPINAL AND TOTAL SPINAL
ANAESTHESIA
 Can occur both with spinal and epidural
 Administration of an excessive dose,failure to reduce
doses in selected pts (elderly,pregnant,obese , very short)
or unusual sensitivity or spread of LA maybe responsible
 SA ascending into cervical level causes severe
hypotension,bradycardia and respiratory insufficiency
and even apnea
 Total spinal can occur following attempted
epidural/caudal anesthesia if there is inadvertent
intrathecal injection
 TREATMENT---vasopressors(to increase BP),atropine(to
treat bradycardia) ,fluids,oxygen ,assisted ventillation(to
overcome respiratory insufficiency) and even intubation
and mechanical ventillation may be needed

79. TRANSIENT NEUROLOGICAL SYMPTOMS
AND CAUDA EQUINA SYNDROME
TNS or transient radicular irritation refers to
pain,dysesthesia or both inthe legs or buttocks
after spinal anesthesia, resolving spontaneously
within several days
Mostcommon with hyperbaric lidocaine and
after surgery in lithotomy position
CES characterized by bowel and bladder
dysfunction together with evidence of multiple
nerve root injury, associated with use of
continous spinal catheters and 5% lidocaine

80. NEURAXIAL BLOCKADE IN SETTING OF ANTICOAGULANTS AND
ANTIPLATELET AGENTS---AMERICAN SOCIETY FOR REGIONAL
ANESTHESIA RECOMMENDATIONS
 Pts taking NSAIDS or receiving subcutaneous unfractioned
heparin for DVT prophylaxsis are not viewed as being at
increased risk of spinal hematoma
 DISCONTINUE---ticlopidine 2 weeks, clopidogrel for 1 week
,abciximab 24 to 48 hrs, eptifibate and tirofiban 4 to 8 hrs
before performing central neuraxial block.
 Pt who are fully anticoagulated or who are receiving
thrombolytic or fibrinolytic theraphy should not receive
central neuraxial block except in very unusual circumstances
where other options are not viable.
 Delay atleast 10 -12 hrs after last dose of LMWH
 Post op t/t with LMWH delay 12hrs after completion of
surgery
 Removal of epidural ,spinal catheters should take place 10—
12hrs after last dose with subs dosing delay for atleast 2hrs.

81. ADVANTAGES OF SPINAL ANESTHESIA (SPA)
1. Cost. The costs associated with SPA are minimal.
2. Patient satisfaction. the majority of patients are very
happy with this technique.
3. Respiratory disease. SPA produces few adverse
effects on the respiratory system as long as unduly
high blocks are avoided.
4. Patent airway. As control of the airway is not
compromised, there is a reduced risk of airway
obstruction or the aspiration of gastric contents.
5. Diabetic patients. There is little risk of unrecognised
hypoglycaemia in an awake patient.

82. ADVANTAGES OF SPA CONTD
6. Muscle relaxation- SPA provides excellent muscle
relaxation for lower abdominal and lower limb
surgery.
7. Bleeding- Blood loss during operation is less than
when the same operation is done under general
anaesthesia
8. Splanchnic blood flow- Because of its effect on
increasing blood flow to the gut, spinal anaesthesia
reduces the incidence of anastomotic dehiscence
9. Visceral tone- The bowel is contracted by SPA and
sphincters relaxed although peristalsis continues.
Normal gut function rapidly returns following surgery.
10. Coagulation- Post-operative deep vein thromboses
and pulmonary emboli are less common following
spinal anaesthesia.

83. THANK YOU