for anesthesia students

1. Neuraxial
Anesthesia
Anesthesia department
Al azhar university
2016

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 and caudal) or into the
cerebrospinal fluid which surrounds the spinal
cord (also known as a spinal).

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 of Regional Anesthesia 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

5. Spinal anesthesia
Spinal anesthesia involves the use of small amounts of local
anesthetic injected into the subarachnoid space to produce
a reversible loss of sensation and motor function. The
anesthesia provider places the needle below L2 in the adult
patient to avoid trauma to the spinal cord. Spinal anesthesia
provides excellent operating conditions for
– Hernia (Inguinal or epigastric).
– Haemorrhoidectomy , fistula , fissure.
– cystectoscopy
– Transurethral resection of the prostate and transurethral resection of the
bladder tumors.
– Abdominal and vaginal hysterectomies
– Caesarean sections.
– Lower limb surgery(orthopedic,plastic,vascular)

6. Vertebral Anatomy
• Each vertebra consists of a pedicle, transverse
process, superior and inferior articular processes,
and a spinous process.
• Each vertebra is connected to the next by
intervertebral disks.
• There are 2 superior and inferior articular processes
(synovial joints) on each vertebra that allows for
articulation.
• Pedicles contain a notch superiorly and inferiorly to
allow the spinal nerve root to exit the vertebral
column.

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

8. Vertebral Anatomy- Top View
Transverse
Process
Vertebral
Body
Spinal Canal
Spinous
Process
Lamina

9. Ligaments that support the vertebral
column
Ventral side:
Anterior and
posterior
longitudinal
ligaments
Dorsal side:
Important
since these
are the
structures
your needle
will pass
through!

10. 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

11. Termination of Spinal Cord
In adults usually ends at L1.
Infants L3
There are anatomical
variations. For most adults it is
generally safe to place a spinal
needle below L2 unless there is
a known anatomic variation.

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

13. CSF
• Clear fluid that fills the subarachnoid space
• Total volume in adults is 100-150 ml
• Volume found in the subarachnoid space is 25-35
ml
• Continually produced at a rate of 450 ml per 24
hour period replacing itself 3-4 times
• Reabsorbed into the blood stream by arachnoid
villi and granulations
• Specific gravity is between 1.003-1.009 (this will
play a crucial role in the baracity of local
anesthetic that one chooses)

14. Membranes that surround the spinal cord
• Pia mater- highly vascular, covers the spinal cord and
brain
• Arachnoid mater- non vascular and attached to the
dura mater. Principal barrier to the migration of
medications in and out of the CSF
• Dura mater (“tough mother”)- extension of the
cranial dura mater, extends from the foramen
magnum to S2 (ending at the filum terminale)

15. Adapted with permission from “Unintended subdural injection: a complication of epidural anesthesia- a case report”, AANA Journal, vol. 74, no. 3, 2006.

16. 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

17. 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

18. Spinal Technique
• Preparation & Monitoring
– EKG
– NBP
– Pulse Oximeter
• Patient Positioning
– Lateral decubitous
– Sitting
– Prone (hypobaric technique)

19. Landmark
• landmark:
iliac crest spinous
processL4-5

20. PATIENT POSITIONING
• SITTING POSITION

21. PATIENT POSITIONING
• LATERAL DECUBITUS

22. Positions for Spinal Tap
Procedures

24. • 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

25. Spinal Anesthesia Levels

26. Complications of Spinal Anaesthesia
• Hypotension
• Bradycardia
• Total Spinal Anesthesia
• Neurological Complecations – Cauda Equina
Syndrome
• Post Dural Puncture Headache
• Infection
• Backache

27. EPIDURAL ANESTHESIA

28. Introduction:
• Epidural anesthesia is a central neuraxial block
technique with many applications.
• The epidural space was first described by Corning in
1901, and Fidel Pages first used epidural anaesthesia in
humans in 1921.
• In 1945 Tuohy introduced the needle which is still most
commonly used for epidural anesthesia.
• it can be used as an anesthetic, as an analgesic
adjuvant to general anesthesia, and for postoperative
analgesia in procedures involving the lower limbs,
perineum, pelvis, abdomen and thorax.

29. Indications:
• Epidural anaesthesia can be used as sole anaesthetic for
procedures involving the lower limbs, pelvis, perineum
and lower abdomen.
• It is possible to perform upper abdominal and thoracic
procedures under epidural anaesthesia alone, but the
height of block required, with its attendant side effects,
make it difficult to avoid significant patient discomfort
and risk.
• The advantage of epidural over spinal anaesthesia is the
ability to maintain continuous anaesthesia after
placement of an epidural catheter, thus making it
suitable for procedures of long duration.

31. Technique of Epidural Anesthesia
 Loss of resistance technique to identify the epidural
space.
– 0.5% Bupivacaine (mainly) or lidocaine (2.0%) is
usually used to produce epidural anaesthesia.
– Local anaesthetic solutions are deposited in the
peridural space between the dura mater and the
periosteum lining the vertebral canal.
– The peridural space contains adipose tissue,
lymphatics and blood vessels.
– The injected local anaesthetic solution produces
analgesia by blocking conduction at the intradural
spinal nerve roots.
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32. 33

33. 34

34. Indication and Contraindication:
• The same of spinal anaesthesia.
• Additional indication is the post operative Pain
management using the epidural catheter
technique.
• Complications: the same of spinal anaesthesia,
except the postdural puncture headache.
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35. Detail Technique of Epidural
Anaesthesia
• Using local anaesthetic raise a subcutaneous wheal at the midpoint
between two adjacent vertebrae.
• Inflitrate deeper in the midline and paraspinously to anaesthetise the
posterior structures.
• Insert epidural needle to the skin at this point, and advance through
the supraspinous ligament, with the needle pointing in a slightly
cephalad (upward) direction.
• Then advance the needle into the interspinous ligament, which is
encountered at a depth of 2-3 cm.
• Until distinct sensation of increased resistance is felt as the needle
passes into the ligamentum flavum.

37.  With 5-10ml of air in the syringe, attach it to the hub of the needle once it
has entered the interspinous ligament.
 The plunger is gently pressed, and if there is resistance ("bounce"), the
needle is very carefully advanced, with the dorsum of both hands resting
against the back to provide stability.
 After 2-3mm, the plunger is again gently pressed, and this procedure is
repeated as the needle is carefully advanced through the tissues.
 The distinctive decrease in resistance when the needle enters the
ligamentum flavum is felt, and the process is continued in 2mm increments.
 There is usually a distinctive "click" when the needle enters the epidural
space, and provided great care is taken, and the needle only advanced in
2mm increments, the needle should stop before it reaches the dura.
 At this point air can be injected into the epidural space very easily. The
syringe is removed and the catheter threaded

38. • Remove the syringe and thread the catheter gently via the needle
into the epidural space.
• The catheter has markings showing the distance from its tip, and
should be advanced to 15-18cm at the hub of the needle, to ensure
that a sufficient length of catheter has entered the epidural space.
• Remove the needle carefully, ensuring that the catheter is not
drawn back with it.
• The markings on the needle will show the depth of the needle from
the skin to the epidural space, and this distance will help determine
the depth to which the catheter should be inserted at the skin.
• For example, if the needle entered the epidural space at a depth of
5cm, the catheter should be withdrawn so that the 10cm mark is at
the skin, thus leaving approximately 5cm of the catheter inside the
epidural space, which is an appropriate length.

39. Choice of drugs:
• The choice of drugs administered epidurally depends on the
indication for the epidural:
• Surgical anaesthesia:Requires dense sensory block and usually
moderate to dense motor block. To achieve this, concentrated local
anaesthetic preparations are required. The most commonly used local
anaesthetics in this setting are 2% lignocaine 10-20ml (with or
without adrenaline 1:200 000) or 0.5% bupivacaine 10-20ml. The
latter has a longer duration of action, but a slower onset time,
compared with lignocaine.
• For analgesia during labour: 0.1-0.25% bupivacaine 5-10ml is more
popular, as it produces less motor block.
• Postoperative analgesia: weaker concentrations of bupivacaine, e.g.
0.1-0.166% with or without added low dose opioids.

40. 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, 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 Peridural space: Using the
Loss of Resistance technique.
Doses: 2.5- 3.5 ml Bupivacaine 0.5% heavy Doses: 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 complication.
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41. Complications and Side Effects
• Hypotension
• Inadvertent high epidural block
• Local anaesthetic toxicity
• Total spinal block

42. CAUDAL ANESTHESIA

43. Introduction:
• Caudal anesthesia has been used for many years and is
the easiest and safest approach to the epidural space.
When correctly performed there is little danger of
either the spinal cord or dura being damaged.
• It is used to provide peri and post operative analgesia
in adults and children.
• It may be the sole anesthetic for some procedures, or it
may be combined with general anesthesia.

44. Indications:
1. Anesthesia and analgesia below the umbilicus
2. Obstetric analgesia :For the 2nd stage or
instrumental deliveries. Care should be taken as
the foetal head lies close to the site of injection
and there is real risk of injecting local anesthetic
into the foetus.
3. Chronic pain problems relating to lower limbs
and lower abdominal pains.

45. Contraindications:
1. Infection near the site of the needle
insertion.
2. Coagulopathy or anti coagulation.
3. Congenital abnormalities of the lower spine
or meninges, because of the unclear or
impalpable anatomy.

46. Anatomy:
• The caudal epidural space
is the lowest portion of the
epidural system and is
entered through the sacral
hiatus.
• The sacrum is a triangular
bone that consists of the
five fused sacral vertebrae
(S1- S5).
• It articulates with the fifth
lumber vertebra and the
coccyx.

47. • The sacral hiatus is a defect
in the lower part of the
posterior wall of the sacrum
formed by the failure of the
laminae of S5 and/or S4 to
meet and fuse in the midline.
• The sacral canal is a
continuation of the lumbar
spinal canal which terminates
at the sacral hiatus.

48. Choice of drugs & dosage:
• Drugs that are commonly used include :
 Lignocaine 1% and
 Bupivacaine 0.25%.

49. Technique:
The patient is prepared as for general anaesthesia:
(1) He/she should be fasted
(2) All appropriate equipment for resuscitation must be
available.
(3) An intravenous cannula should always be inserted in an
upper limb, in case of accidental intravenous injection, or
profound sympathetic blockade from a high epidural block.
(4) The procedure must be carried out with a strict aseptic
technique. The skin should be thoroughly prepared and
sterile gloves worn.

50. (5) There are three main approaches:
• The prone, the semi-prone, and the lateral. The choice
depends on the preference of the anesthetist and the
degree of sedation of the patient. The caudal space is made
more prominent by asking the patient to internally rotate
their ankles.
 The semi-prone position is preferred for the anesthetised or
heavily sedated patient as the airway is easier to control in
this position, while still allowing reasonably easy access to
the sacral hiatus.
 The lateral position is often used in children, as the
landmarks are easier to find than in adults. Care should be
taken to avoid over flexing the hips (as for lumber epidurals)
as this can make the landmarks more difficult to palpate

51. 6) The landmarks are
palpated. The sacral hiatus
and the posterior superior
iliac spines form an
equilateral triangle pointing
inferiorly.
• The sacral hiatus can be
located by first palpating
the coccyx, and then sliding
the palpating finger in a
cephalad direction until a
depression in the skin is
felt.

53. 7) Once the sacral hiatus is
identified the area above
is carefully cleaned with
antiseptic solution, and a
22 gauge cannula or
needle is directed at
about 90 degree to skin
and inserted till a "click"
is felt as the sacro-
coccygeal ligament is
pierced.

54.  Care should be taken not to insert the needle too far as the
dura lies at or below the S2 level in the child.
The needle should be aspirated looking for either CSF or
blood. The injection should never be more than 10 ml/30
seconds
• Further tests to confirm the correct position include:
Introduction of a small amount of air will not produce
subcutaneous emphysema, and will be heard as a "woosh"
sound if a stethoscope is place further up the lumbar spine.
There should be no local pain during injection.

55. (9) A small amount of local anaesthetic should be injected
as a test dose (2-4mls). It should not produce either a
lump in the subcutaneous tissues, or a feeling of
resistance to the injection, nor any systemic effects
such as arrhythmias or hypotension.
 If the test dose does not produce any side effects then
the rest of the drug is injected, the needle removed and
the patient positioned for surgery. In the post-operative
period, motor function must be checked and the
patient should not be allowed to try and walk until
complete return of motor function is assured. The
patient should not be discharged from hospital until
he/she has passed urine, as urinary retention is a
recognized complication.

56. Complications:
 Intravascular or intraosseous injection:This may lead to grandmal
seizures and/or cardio-respiratory arrest.
 Dural puncture: Extreme care must be taken to avoid this as a total
spinal block will occur if the dose for a caudal block is injected into
the subarachnoid space. If this occurs then the patient will become
rapidly apnoeic and profoundly hypotensive.
 Perforation of the rectum: Contamination of the needle is
extremely dangerous if it is then inserted into the epidural space.
 Sepsis:This should be a very rare occurrence if strict aseptic
procedures are followed.
 Urinary retention.
 Haematoma