Central neuroaxial blockade

For undergraduate teaching

2. Neuraxial Anesthesia
Neuraxial anesthesia is a type of regional anesthesia
that involves injection of anesthetic medication in the
fatty tissue that surround the nerve roots as they exist
the spine (also known as an epidural) or into the
cerebrospinal fluid which surrounds the spinal cord
(also known as a spinal). This numbs the patient
from the abdomen to the toes and often eliminates
the need for general anesthesia.

3. HISTORY
1885 - J. Leonard Corning –
first spinal anesthetic was administered accidentally
The needle was made of gold
1898 - August Bier - first planned spinal anesthesia
for surgery
In 1921, Spanish military surgeon Fidel Pagés (1886–
1923) developed the modern technique of lumbar
epidural anesthesia
Robert Andrew Hingson (1913–1996), working at
the United States Marine Hospital in New York,
developed the technique of continuous caudal
anesthesia.

4. Advantages over Regional
Anaesthesia over GA
Safe, reliable technique in patients at risk of apnoea,
bradycardia, desaturation, cardiac or respiratory complications
after GA
Good alternative for day care surgeries
Minimal risk of postoperative respiratory depression
Limited stress response to surgery
Cost effective

6. VERTEBRA
33 Vertebrae
◦7 Cervical
◦12 Thoracic
◦5 Lumbar
◦5 Sacral
◦4 Coccygeal

7. Spinal Cord
Spinal Cord
Adult
Begins: Foramen Magnum
Ends: L1
Newborn
Begins: Foramen Magnum
Ends: L3
Terminal End: Conus Medullaris
Filum Terminale: Anchors in sacral region
Cauda Equina: Nerve group of lower dural sac

8. Sagittal Section Through Lumber Vertebrae
Supraspinous
Ligament
(Outer most layer)
Intraspinous
Ligament
(Middle layer)
Ligamentum
Flavum
(Inner most layer)

9. CONTRAINDICATIONS
Absolute
Patient Refusal
Infection At The Site Of Injection
Coagulopathy And Other Bleeding Disorders
Severe Hypovolemia
Increased Intracranial Pressure
Severe Aortic Stenosis
Severe Mitral Stenosis

10. CONTRAINDICATIONS
Relative
Sepsis
Uncoperative Patient
Preexisting Neurological Deficits
Severe Spinal Deformity
Controversial
Prior Surgery At The Site Of Injection
Complicated Surgery
Prolonged Operation
Major Blood Loss

11. SURFACE ANATOMY

12. PATIENT POSITIONING
SITTING POSITION

13. PATIENT POSITIONING
LATERAL DECUBITUS

14. Midline Approach
Skin
Subcutaneous tissue
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Epidural space
Dura mater
Arachnoid mater
Paramedian or Lateral Approach
Same as midline excluding supraspinous &
interspinous ligaments
Anatomic Approach

15. Spinal Needle Types
Quincke Whitacre Sprotee

16. Selection of equipments
Selection of block needles and catheters:
Block procedureRecommended device
Spinal
anaesthesia
Spinal needle (24-25 gauge; 30, 50 or 100 mm
long, Quincke bevel, stylet)
Caudal
anaesthesia
Short (25-30 mm) and short beveled (45-degree)
needle with stylet
Epidural
anaesthesia
Tuohy needle (22, 20, and 19/18 gauge); LOR
syringe and medium epidural catheter
PNB Insulated 21-23 gauge short beveled needles

17. FACTORS AFFECTING LEVEL
BARICITY OF DRUG
POSITION OF PATIENT
DOSE
SITE
AGE
CURVATURE OF SPINE
PATIENT HEIGHT
PREGNANCY

18. Spinal Anesthesia Levels

19. DRUGS
BUPIVACAINE HEAVY
DOSE
<5 KG -- 0.5MG/KG BODY WT
5-15 KG -- 0.4MG/KG BODY WT
>15 KG -- 0.3MG/KG BODY WT

20. Complications of Spinal Anaesthesia
Hypotension
Bradycardia
Cardiac Arrest
Total Spinal Anesthesia
Neurological Complecations – Cauda Equina
Syndrome
Post Dural Puncture Headache
Infection

21. Backache
Inflammatory reaction due to tissue trauma
May result in back spasms
Short lived, analgesics, ice
May last a few weeks
Back ache may be a sign of serious complications
such as epidural/spinal hematoma, abscess
Careful evaluation to determine if a
common/benign complication or something more
serious

22. Postdural Puncture Headache
Caused by disrupting the integrity of the dura
Can occur due to: spinal anesthesia, “wet” tap with
epidural, epidural catheter migration, tip of the
epidural needle “indenting” the dura enough to cause
a leak.
Headache occurs due to leakage of CSF through the
dura
Decrease in intracranial pressure occurs due to the
leak
Upright position in the patient leads to traction on
the dura, tentorium, and blood vessels resulting in
pain.

23. Postdural Puncture Headache- Symptoms
Onset is generally within 12-72 hours
Headache associated with upright position (i.e.
sitting or standing). Relief found with a supine
position
Headache may be bilateral, frontal, retroorbital
and/or occipital with or without radiation to the neck
Described as “throbbing” or constant
May be associated with nausea and/or photophobia
Traction on the 6
th
cranial nerve can result in diplopia
and tinnitus

24. Postdural Puncture Headache- Conservative
Treatment
Hydration- theoretically helps to encourage the
production of CSF.
Analgesics- will decrease the severity of
symptoms and include acetaminophen and
NSAIDS
Caffeine- Helps to decrease symptoms by
vasoconstriction of the cerebral vessels.
A dose of 300 mg of oral caffeine has been shown
to decrease the intensity of PDPH
Epidural blood patch.

25. Epidural Space
Space that surrounds the
spinal meninges
Potential space
Ligamentum Flavum
Binds epidural space
posteriorly
Widest at Level L2 (5-6mm)
Narrowest at Level C5 (1-
1.5mm)

26. Epidural Anatomy
Safest point of entry is
midline lumbar
Spread of epidural
anesthesia parallels
spinal anesthesia
◦Nerve rootlets
◦Nerve roots
◦Spinal cord

27. Epidural Anesthesia
Order of Blockade
B fibers
C & A delta fibers
Pain
Temperature
Proprioception
A gamma fibers
A beta fibers
A alpha fibers

28. Epidural Anesthesia
Test Dose: 1.5% Lido with Epi 1:200,000
◦Tachycardia (increase >30bpm over resting HR)
◦High blood pressure
◦Light headedness
◦Metallic taste in mouth
◦Facial numbness
◦Note: if beta blocked will only see increase in BP not
HR
Bolus Dose: Preferred Local of Choice
◦10 milliliters for labor pain
◦20-30 milliliters for C-section

29. Epidural Anesthesia
Distances from Skin to Epidural Space
Average adult: 4-6cm
Obese adult: up to 8cm
Thin adult: 3cm
Assessment of Sensory Blockade
Alcohol swab
Most sensitive initial indicator to assess loss of temperature
Pin prick
Most accurate assessment of overall sensory block

30. Epidural Anesthesia
Complications
Penetration of a blood vessel
Hypotension (nausea & vomiting)
Intravascular catheterization
Back pain
Wet tap
Infection

31. Differences between Spinal and Epidural Anesthesia
Spinal anaesthesia Extradural Anaesthesia
Level: below L1/L2, where the spinal cord
ends
Level: at any level of the vertebral column.
Injection: subarachnoid space i.e punture
of the dura mater
Injection: epidural space (between
Ligamentum flavum and dura mater) i.e
without punture of the dura mater
Identification of the subarachnoid space:
When CSF appears
Identification of the Peridural space: Using
the Loss of Resistance technique.
Dosis: 2.5- 3.5 ml bupivacaine 0.5% heavyDoses: 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 complicationHeadache: is not a probable.
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32. Caudal Anaesthesia
Block of the sacral and lumbar
nerve roots. This technique is
popular in pediatric patients.
The S5 processes are remnants and
form the cornua, which provide the
main landmarks for indentifying
the sacral hiatus. The hiatus is
covered by the sacro-coccygeal
membrane.
The canal contains areolar
connective tissue, fat, sacral
nerves, lymphatics, the filum
terminale and a rich venous plexus.

33. Caudal anaesthesia
Indications of caudal anaesthesia:
Surgical procedures below the umbilicus
As an adjuvant to GA
Sole anaesthetic technique in fully awake ex-premature infants
younger than 60 wk of post conceptual age
Contraindications to caudal anaesthesia:
Major malformations of sacrum (myelomeningocele, open
spina bifida)
Meningitis
Intracranial hypertension

34. Caudal Doses
Pediatric population
0.5 ml/kg, 0.25% bupivacaine
(sacro-lumbar block)
1 ml/kg, 0.25% bupivacaine
(upper abdominal block)
1.2 ml/kg,0.25% bupivacaine
(mid-thoracic block)
(Doses described by
Armitage).
Adults:
20-30 ml 0.25-0.5%
bupivacaine. Average
volume of the sacral canal is
30-35 ml.

35. Caudal Anesthesia
Anatomy
Sacrum
Triangular bone
5 fused sacral vertebrae
Needle Insertion
Sacrococcygeal membrane
No subcutaneous bulge or
crepitous at site of
injection after 2-3ml

36. Caudal Anesthesia
Post Operative Problems
Pain at injection site is most common
Slight risk of neurological complications
Risk of infection

37. Complications and side effects of
neuraxial methods

38. THE END
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