Complications of Neuraxial Blockade

1
Complications of Neuraxial Blockade
Soli Deo Gloria

• Developing Countries Regional Anesthesia Lecture
  Series
• Daniel D. Moos CRNA, Ed.D. U.S.A.
  moosd_at_charter.net

Lecture 13
2
Disclaimer

• Every effort was made to ensure that material and
  information contained in this presentation are
  correct and up-to-date. The author can not
  accept liability/responsibility from errors that
  may occur from the use of this information. It
  is up to each clinician to ensure that they
  provide safe anesthetic care to their patients.

3
Introduction

• Exaggerated physiological response
• Associated with needle placement
• Associated with catheter placement
• Associated with medication toxicity

4
Medical Liability- In General

• Administration of regional anesthesia constitutes
  18 of all claims in the US
• 64 are temporary and non disabling
• 13 involve death
• 10 permanent nerve injury
• 8 brain damage
• 4 are other

5
Medical Liability- Neuraxial Blockade

• 76 of all claims were related to neuraxial
  blockade
• Epidurals comprised 42
• Spinals comprised 34
• Caudal comprised 2
• The population most affected is the obstetric
  population

6
Adverse or Exaggerated Physiological Response
Include

• High neural blockade
• Cardiac arrest
• Urinary retention

7
Adverse or Exaggerated Physiological Response

• This category is an extension of normal
  physiologic manifestations.
• The main point is vigilance and early treatment.
  Treat hypotension early and do not let it
  progress to cardiac arrest.
• Knowledge, preparation, and anticipation can help
  reduce adverse or exaggerated physiological
  responses

8
High Neural Blockade

• Can occur with either spinal or epidural
  techniques

9
High Neural Blockade Causes

• Excessive doses of local anesthetic are
  administered
• Failure to reduce dose in patients susceptible to
  excessive spread (i.e. the elderly, pregnant,
  obese, or short patients)
• Unusual sensitivity
• Unusual excessive spread

10
High Neural Blockade

• Constant monitoring of the patients vital signs
  and block level are imperative
• Use of alcohol wipes (to assess cold sensation)
  and/or pinprick test will help
• Incremental dosing is important with an epidural
• With hyperbaric techniques you can change the
  patients position to slow down the cephalad
  spread (i.e. reverse Trendelenberg)

11
High Neural Blockade-Prevention

• Careful consideration in dosing your block
• Anticipation of potential complications
• Plan of action if complications occur
• Continual monitoring of the patient as the block
  progresses

12
High Neural Blockade- Initial Symptoms

• Dyspnea
• Numbness and tingling of the upper extremities
  (i.e. fingers)
• Nausea generally precedes hypotension due to
  hypoperfusion of the chemoreceptor trigger zone
• Mild to moderate hypotension

13
High Neural Blockade- Initial Treatment

• Change position with hyperbaric technique
• Stop the administration of local anesthetics with
  an epidural technique
• Supplemental oxygen
• Open up the IV fluids
• Treat hypotension with ephedrine or phenylephrine
• Treat bradycardia

14
High Neural Blockade- Initial Treatment

• Choose your vasopressor carefully.
• If patient is hypotensive and bradycardic then
  ephedrine would be indicated
• Ephedrine will increase heart rate as well as
  constrict blood vessels
• Phenylephrine can result in reflex bradycardia as
  it constricts blood vessels
• If patient is hypotensive and tachycardic or
  normal in respect to heart rate then
  phenylephrine may be indicated

15
High Neural Blockade- Initial Treatment

• Refractory hypotension and/or hypotension should
  be treated rapidly with 5-10 mcg of epinephrine

16
High Neural Blockade- Spread to Cervical
Dermatomes Signs and Symptoms May Include

• Severe hypotension
• Bradycardia
• Respiratory insufficiency including apnea
• Unconsciousness

17
High Neural Blockade- Cervical Dermatomes
Treatment

• The A,B,Cs
• Airway and breathing- supplemental oxygen,
  maintain a patent airway, intubation, mechanical
  ventilation
• Circulation- aggressive intravenous fluid
  administration, ephedrine, phenylephrine,
  epinephrine
• Bradycardia should be treated with atropine
• Dopamine infusions may help

18
High Neural Blockade- Cervical Dermatomes
Treatment

• Early and aggressive treatment may help avoid a
  cardiac arrest!
• Once patient has been stabilized and successfully
  treated the decision to proceed is based on
  individual circumstances
• Considerations include time spent hypotensive,
  indications of myocardial ischemia, etc.
• The respiratory compromise associated with high
  neural blockade are often transient

19
Cardiac Arrest Due to Neuraxial Blockade
20
Cardiac Arrest Due to Neuraxial Blockade

• Cardiac arrest can occur with either epidural or
  spinal anesthesia
• More common with spinal anesthesia and the
  incidence may be as high as 11,500
• Usually preceded by bradycardia
• Can easily occur in the young and healthy

21
Cardiac Arrest Due to Neuraxial Blockade- Keys to
Prevention

• Appropriate hydration (i.e. 1 liter to an average
  sized adult)- must be administered within
  approximately 15 minutes since the majority of
  crystalloid solution will leave the intravascular
  space
• Aggressively treat bradycardia, atropine,
  ephedrine, epinephrine
• Do not be fooled by the 26 year old marathon
  runner- patients with a slow heart rate and high
  vagal tone are at risk for cardiac arrest during
  spinal anesthesia
• Total sympathectomy with unopposed vagal
  stimulation
• Error on the conservative and treat the patient

22
Cardiac Arrest Due to Neuraxial Blockade- Risk
Factors

• Baseline heart rate lt 60 bpm
• ASA class I
• Use of Beta Blockers
• Sensory level gt T6
• Prolonged P-R interval

23
Urinary Retention
24
Urinary Retention

• Due to blockade of S2-S4
• Leads to a decrease in bladder tone and
  inhibition of normal voiding reflex
• Neuraxial opioids may contribute to urinary
  retention
• More common in elderly men and those with a
  history of benign prostatic hypertrophy

25
Urinary Retention

• Urinary catheterizes should be provided for
  patients undergoing moderate to lengthy
  procedures
• Postoperative assessment is important to detect
  urinary retention
• Prolonged urinary retention may be a sign of
  serious neurological injury

26
Complications Associated with Needle Placement or
Catheter Insertion

• Inadequate anesthesia or analgesia
• Inadvertent intravascular injection
• Total spinal
• Subdural injection
• Backache
• Postdural puncture headache
• Neurological injury
• Spinal or epidural hematoma
• Meningitis and arachnoiditis
• Epidural abscess
• Sheering off the tip of the epidural catheter

27
Inadequate Analgesia or Anesthesia

• Rate of block failure is low but can be
  frustrating
• Must always be prepared to convert to general
  anesthesia or supplement
• Rate of block failure decreases as experience
  increases

28
Inadequate Analgesia or Anesthesia- May be
associated with

• Outdated or improperly stored local anesthetics
  (tetracaine looses potency when stored for long
  periods in a warm environment)

29
Inadequate Analgesia or Anesthesia- May be
associated with

• Needle movement once free flowing CSF is noted-
  helpful to confirm aspiration before, during, and
  after injection
• Even with free flowing CSF it is possible that
  the spinal needle is not entirely in the
  subarachnoid space resulting in a partial
  subdural injection and partial spinal

30
Inadequate Analgesia or Anesthesia- May be
associated with

• Epidural anesthesia is more subjective since you
  have to rely on confirmation by loss of
  resistance or hanging drop technique
• Either technique can lead to false positives
• Spread of local anesthetic is less predictable

31
Inadequate Analgesia or Anesthesia- May be
associated with anatomical factors with epidural

• Soft spinal ligament can occur in the very young
  and in obstetricsthis results in never achieving
  a good loss of resistance
• If you are off the midline slightly you may be in
  the paraspinous muscle and not in the spinal
  ligaments

32
Inadequate Analgesia or Anesthesia- May be
associated with anatomical factors with epidural

• Block failure may occur if the epidural catheter
  migrates into the subdural space
• Injection of local anesthetics into this space
  may result in Horners syndrome, a high spinal,
  or an absence of any effect

33
Inadequate Analgesia or Anesthesia

• Local anesthetic toxicity can occur if the
  epidural catheter is placed into a vessel
• A high spinal can occur if the epidural catheter
  is placed in a subarachnoid space- stresses
  importance of the test dose

34
Inadequate Analgesia or Anesthesia

• Septations within the epidural space may create a
  barrier to the spread of local anesthetic and
  some segments may lack anesthesia
• L5, S1, S2 are all large nerve roots and the
  large size may prevent penetration of local
  anesthetic- correct by making the area dependent
  and adding local anesthetic

35
Inadequate Analgesia or Anesthesia

• Visceral pain can occur even if the epidural is
  adequate. Visceral afferent fibers travel with
  the vagus nerve.
• May increase the level of epidural anesthesia to
  the thoracic levels with additional local
  anesthetic
• IV sedatives and opioids may help

36
Inadequate Analgesia or Anesthesia- Failed
Epidural

• Not waiting long enough to let it work
• Catheter is inserted too far resulting in a
  unilateral blockpull back the catheter 1-2 cm
  and add local anesthetic with the unaffected side
  down

37
Inadvertent Intravascular Injection

• Risk with spinal anesthesia is extremely low
• Risk generally lies with epidural or caudal
  anesthesia
• Toxicity will affect the central nervous system
  and cardiovascular system

38
Inadvertent Intravascular Injection

• Local anesthetics vary in their potential to
  cause toxicity
• Least to most toxic local anesthetics are as
  follows
• Chloroprocainelt lidocaine lt mepivacaine lt
  levobupivacainelt ropivacaine lt bupivacaine

39
Inadvertent Intravascular Injection- Symptoms

• Hypotension
• Arrhythmias
• Cardiovascular collapse
• Seizures
• Unconsciousness

40
Inadvertent Intravascular Injection- Prevention

• Test dose
• Careful aspiration prior to injection
• Incremental dosing
• Vigilant monitoring for early signs and symptoms
  of intravascular injection
• Early symptoms include increase heart rate (if
  epi used), tinnitus, funny taste or metallic
  taste, subjective changes in mental status

41
Inadvertent Intravascular Injection- Prevention

• With early symptoms stop administration and
  anticipate impending complications such as
  seizures and hypotension, etc.
• Re-evaluate placement of catheter and reinsert as
  needed

42
Local Anesthetic Toxicity Treatment

• Standard ACLS treatment
• Bretyllium may be more effective than other forms
  of antiarrhythmics

43
On the Horizon- Intralipids

• Several successful resuscitations of local
  anesthetic overdose as well as other lipophilic
  medication overdoses
• Local anesthetics are amphipathic (have an
  affinity for both lipid and water)
• This makes local anesthetics potentially toxic
  for several tissues including the heart, brain,
  and skeletal muscles

44
On the Horizon- Intralipids

• Intralipids expand the lipid compartment and
  allow for local anesthetic binding (there are
  more involved and technical explanations but lets
  keep it simple)

45
Lipid Rescue Protocol (Experimental)

• 20 Intralipid
• 1.5 mg/kg initial bolus
• 0.25 mg/kg/min infusion for 30-60 minutes
• Bolus may be repeated 1-2 times for persistent
  asystole
• May increase infusion rate if blood pressure
  decreases
• See lipidrescue.com for more information

46
Subdural Injection

• Subdural space is a potential space that is found
  between the dura and arachnoid space
• It contains a small amount of serous fluid
• Subdural space extends from the epidural space to
  the intracranial space
• Local anesthetics can travel further in the
  subdural space than they can in the epidural space

47
Subdural Injection

• Small doses of local anesthetic can travel far in
  the subdural space
• Small doses of local anesthetic associated with a
  spinal may result in no local anesthetic blockade
• Larger doses of local anesthetics associated with
  epidural analgesia may result in Horners Syndrome

48
Subdural Injection

• Manifestations of Horners syndrome include
  miosis (constriction of the pupil) ptosis
  (drooping of the upper eyelid) and anhidrosis
  (diminished or absent sweating).

49
Horners Syndrome
50
Subdural Injection

• Larger doses of local anesthetics associated with
  epidural anesthesia may result in a total spinal.
• Prevention is slightly more difficult as
  aspiration will generally be negative
• With slow incremental dosing you may note a
  higher and faster progression of blockade than
  would be normally expected

51
Backache
52
Backache

• Up to 30 of patients undergoing general
  anesthesia will complain of back pain
• Large number of patients suffer from chronic back
  pain
• Not a contraindication
• Patient should be aware that spinal or epidural
  anesthesia may result in some discomfort

53
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

54
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.

55
Postdural Puncture Headache

• 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.
• Traction on the 6th cranial nerve can result in
  diplopia and tinnitus

56
Postdural Puncture Headache- Symptoms

• 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

57
Postdural Puncture Headache- Symptoms

• Onset is generally 12-72 hours rarely is the
  onset immediate
• If untreated it may last for weeks

58
Postdural Puncture Headache- Associations

• Increased incidence related to needle size,
  needle type and patient population
• The larger the needle the higher the incidence
• Cutting point needles have a higher incidence of
  post dural puncture headache than pencil points
• When using cutting point needles orientate the
  bevel sideways so it will be parallel with the
  fibers. This will act to spread the fibers as
  opposed to cutting them

59
Postdural Puncture Headache- Associations

• Recent literature may indicate that pencil points
  actually cause more trauma then cutting needles.
  This actually may reduce the incidence of
  headache secondary to a localized inflammatory
  response.
• Increased post dural puncture headache in younger
  patients, in female patients, and in pregnant
  patients

60
Postdural Puncture Headache

• Some advocate the prophylactic treatment if a wet
  tap occurs with an epidural needle.
• Methods include epidural blood patch, epidural
  dextan, or epidural saline.
• A wet tap with a 17 g. epidural needle will yield
  a 50 incidence of pdph
• A prophylactic epidural blood patch performed
  within 24 hours of a wet tap has a 71 failure
  rate.
• After 24 hours there is a failure rate of 4

61
Postdural Puncture Headache

• Epidural blood patches are not without risk.
• Remember 50 of the patients with a wet tap
  will not get a post dural puncture headache.
• Conservative measure would be to wait and see if
  symptoms occur
• Prophylactic treatment will only result in
  unnecessary treatment in 50 of the patients

62
Postdural Puncture Headache- Conservative
Treatment

• Symptoms can be debilitating
• Start with conservative measures
• Supine position- will reduce symptoms, no
  evidence that bed rest will reduce the duration
  of post dural puncture headache. Theoretically
  it should decrease the amount of CSF leak and
  allow replacement of lost CSF

63
Postdural Puncture Headache- Conservative
Treatment

• Hydration- theoretically helps to encourage the
  production of CSF. A dehydrated patient may
  experience more severe symptoms and hydration is
  important. The one study looking at this did not
  find that hydration decreased the incidence of
  post dural puncture headache.

64
Postdural Puncture Headache- Conservative
Treatment

• Caffeine- theoretically helps to decrease sx by
  vasoconstriction of the cerebral vessels. May
  decrease symptoms but does not necessarily
  decrease the number of patients that will require
  an epidural blood patch.
• IV caffeine can be administered in a dose of 500
  mg
• Oral caffeine can be encouraged.
• A dose of 300 mg of oral caffeine has been shown
  to decrease the intensity of pdph

65
Caffeine Content of Common Beverages
66
Postdural Puncture Headache- Conservative
Treatment

• Analgesics- will decrease the severity of
  symptoms and include acetaminophen and NSAIDS
• Stool softners and soft diet may help decrease
  Valsalva straining which may increase leakage of
  CSF

67
Postdural Puncture Headache- Conservative
Treatment

• Conservative treatment is mainly symptomatic

68
Postdural Puncture Headache- Epidural Blood Patch

• Definitive treatment
• Successfully resolves 90 of all post dural
  puncture headache after the first treatment
• Generally offered 12-24 hours after the
  initiation of conservative treatment
• Not without risk

69
Postdural Puncture Headache- EBP Precautions

• Check patients history for contraindications
• Check coagulation status
• Ensure no anticoagulants have been administered
  (i.e. DVT prophylaxis)
• Ensure that the patient is not bacteremic
• Jehovahs Witness patients may refuse an epidural
  blood patch based on religious beliefs

70
Postdural Puncture Headache- Epidural Blood Patch

• Involves injection of 15-20 ml of the patients
  own blood at the level of dural puncture
• May be administered one space below the dural
  puncture site
• Blood patch works by mass effect and stops the
  leakage of CSF or alternatively by coagulating
  and plugging the hole

71
Postdural Puncture Headache- Epidural Blood Patch

• Inform the patient of risks and benefits
• Same as with any neuraxial technique with the
  addition of the increased risk of meningitis or
  infection (the blood that is removed can be
  contaminated and placed at an area that has
  breached the blood brain barrier
• Inform the patient that it is only 90 effective
  and not 100 effective

72
Postdural Puncture Headache- Epidural Blood Patch
Technique

• Assemble your supplies- mask, sterile gloves,
  epidural tray, additional betadine and alcohol,
  sterile needle for venipuncture and tourniquet.
• Prior to locating the epidural space identify a
  suitable vein to draw blood. Prep the area with
  betadine and consider draping the area with
  sterile towels

73
Postdural Puncture Headache- Epidural Blood Patch
Technique

• Perform usual steps for locating the epidural
  space
• Once epidural space is identified then have your
  assistant aseptically withdraw 15-20 ml of blood.
  Keep the blood sterile.
• Ensure no contamination of the blood has occurred

74
Postdural Puncture Headache- Epidural Blood Patch
Technique

• Place 15-20 ml of blood into the epidural space

75
Postdural Puncture Headache- Epidural Blood Patch
Technique

• The patient should not experience pain but may
  note pressure
• The patient should remain supine for 1-2 hours
• The patient should avoid lifting heavy items or
  straining for 48 hours (thus avoiding the
  dislodgement of the epidural blood patch

76
Neurological Injury

• Can be transient or permanent
• Prevention is done by avoiding trauma to the
  nerve roots or spinal cord
• Identification of appropriate landmarks is
  essential
• Always document pre-existing neurological
  deficits
• Ask the patient if they suffer from neuropathy,
  chronic or acute low back pain, motor deficits.

77
Neurological Injury

• Document concurrent conditions that may
  contribute to postoperative neuro deficits such
  as peripheral vascular disease, diabetes,
  intervertebral disk injury, spinal disorders.
• Perform subarachnoid anesthesia below L1 in
  adults and L3 in children
• Multiple attempts will increase the risk of
  trauma- avoid this by proper positioning,
  identification of landmarks, and take your time
  being deliberate when performing neuraxial
  techniques

78
Neurological Injury

• If difficulty is encountered do not be afraid to
  ask another provider to help
• If a paresthesia is encountered make sure it is
  transient and redirect the needle
• When inserting a catheter or injecting and the
  patient experiences pain stop. Direct injection
  into the spinal cord can lead to paraplegia

79
Neurological Injury

• Document the presence of paresthesia or pain
  during neuraxial blockade
• Alternatively if the neuraxial technique has been
  performed without any problems document this
  (i.e. no pain, no paresthesia, etc.)

80
If the patient experiences a neuro deficit after
neuraxial blockade

• Possible causes include surgical positioning
• Improper positioning in the post op period
• Direct trauma related to surgery
• Rule out hematoma or abscess
• OB patients at risk for neuro deficits related to
  c-sec and vaginal delivery

81
Obstetric Causes

• Incidence of neurological complications in OB
  range from 12,600-6,400 and often related to
  difficult deliveries.
• Prolapse of intervertebral disk and subsequent
  nerve root compression can occur.

82
Obstetric Causes

• Injury related to descending head or mid to high
  forcep use include lumbrosacral injury (L4, L5).
  Results in foot drop, weakness of hip adduction
  and quadriceps.
• Acute hip flexion and retractors during a
  cesarean section can result in injury to the
  femoral nerve (L2, L3, L4). Results in quadricep
  paralysis, abscent patellar reflex, and altered
  sensation of anterior thigh and medial calf.

83
Obstetric Causes

• Incorrect lithotomy positioning and retractors
  during a cesarean section can injury the lateral
  femoral cutaneous nerve (L2, L3). This will
  alter sensation on the anterolateral thigh.
• Incorrect lithotomy position with knee extension
  and external hip rotation may injure the sciatic
  nerve (L4,L5,S1,S2,S3). This will result in
  sciatic type pain (from gluteal area to foot) and
  the inability to flex the leg.

84
Obstetric Causes

• Lithotomy position with acute flexion of thigh
  may lead to injury to the obturator nerve
  (L2,L3,L4). This may lead to weak or paralyzed
  thigh adduction.
• Compression of lateral knee may lead to common
  peroneal nerve injury (L4, L5, S1, S2). This
  will result in foot drop and the inability to
  stand erect.

85
Obstetric Causes

• Lithotomy positioning may result in injury to the
  saphenous nerve (L2, L3, L4). Loss of sensation
  in the medial foot and anteromedial lower leg.

86
Document New Neurological Deficits

• Is the neuropathy in the distribution of
  neuraxial blockade? (usually transient)
• Is there sharp back pain? Leg pain? (severe
  symptoms may indicate epidural hematoma or
  Transient Neurological Symptoms)
• Is there progressive numbness, motor blockade, or
  sphincter dysfunction? (may be spinal or epidural
  hematoma)

87
Document New Neurological Deficits

• Trauma to conus medullaris generally results in
  sacral dysfunction and you will see
• Paralysis of biceps femoral muscle
• Sensory loss of the posterior thigh, perineal
  area, or great toes
• Bowel and bladder dysfunction

88
Document New Neurological Deficits

• After evaluation of sx it is reasonable to have a
  neurological consult

89
Spinal/Epidural Hematoma

• 1150,000 for epidurals
• 1220,000 for spinals

90
Factors associated with Spinal/Epidural Hematoma

• Abnormal coagulation due to disease/meds
• Multiple attempts at neuraxial blockade
• Formation after the removal of the epidural
  catheter

91
Spinal/Epidural Hematoma

• Presence of blood in the subarachnoid or epidural
  space will result in the compression of neural
  tissue
• There is no way to apply pressure and stop the
  bleeding due to the anatomy.
• Compression results in ischemia and subsequent
  injury

92
Spinal/Epidural Hematoma Symptoms (generally
rapid)

• Sharp back and leg pain
• Progression of numbness and motor weakness
• Sphincter dysfunction

93
Spinal/Epidural Hematoma

• Rapid diagnosis is essential
• MRI/CT scan can diagnose this complication
• Surgical decompression must occur in 8-12 from
  the onset of symptoms to avoid permanent injury

94
Meningitis

• Meningitis is very rare
• Must always use strict sterile technique
• Always wear a mask and change it frequently even
  in OB

95
Meningitis

• Most common cause of bacterial meningitis is from
  contamination of the puncture site by aerosolized
  mouth particles
• Viridans streptococcus is the dominant organism
  and is found in the mouth
• Stresses the importance of masks!

96
Meningitis

• To a lesser extent skin bacteria can result in
  meningitis
• Care should be taken in securing the device with
  sterile materials
• Skin bacteria could track there way into the
  epidural space

97
Meningitis

• Presentation is very similar to a post dural
  puncture headache
• Exception is there is no postural component to
  the headache, there is generally a fever, and
  alteration in level of consciousness

98
Arachnoiditis

• Very rare
• More common in the past when supplies where
  reused
• Chemical arachnoiditis can occur with intrathecal
  injection of steroids
• Lumbar arachnoiditis is more commonly associated
  with surgical procedures or trauma

99
Epidural Abscess

• Rare
• Incidence 16,500- 1500000
• May develop independent of neuraxial techniques

100
Epidural Abscess-risk factors

• Back trauma
• IV drug abuse
• Neurological surgical procedures
• Those associated with neuraxial techniques are
  commonly due to indwelling epidural catheters
• Symptoms develop between 5 days and several weeks

101
Epidural Abscess-Stages of Development

• Stage 1 back and vertebral pain intensified by
  percussion. Any patient with back pain and a
  fever should alert the anesthesia provider to the
  possibility of an abscess
• Stage 2 progresses to nerve root and radicular
  pain

102
Epidural Abscess-Stages of Development

• Stage 3 motor, sensory and/or sphincter
  dysfunction
• Stage 4 paralysis and or paraplegia

103
Epidural Abscess-Prognosis

• Dependent upon when diagnosed, the earlier the
  better
• Epidural catheter should be removed immediately
• Tip sent for cultures (not always accurate)
• Epidural site should be examined for signs and
  symptoms of infection
• Blood cultures should be sent for evaluation
• Any drainage from the site should be sent for
  evaluation

104
Epidural Abscess-Prognosis/Treatment

• Neuro consult
• Most common agents include staph auerus and
  staphylococcus epidermis
• Antibiotic coverage
• MRI/CT
• Possible decompression lami

105
Epidural Abscess-Prevention

• Sterile technique (hat, mask, sterile gloves,
  hand washing, sterile field, proper prep of the
  skin etc.)
• If there is any doubt to contamination, stop and
  start over
• If epidural cath becomes disconnected you must
  decide whether to aseptically reattach it or
  remove the catherter

106
Epidural Abscess-Prevention

• Reduce epidural catheter manipulation
• Maintain a closed system always
• Use bacterial filter that comes with the kit
• Remove the catheter after 96 hours and if needed
  then replace it with a new one at a new site

107
Shearing Off the Tip of the Epidural Catheter

• Never attempt to withdraw the epidural catheter
  through the epidural needle
• If you need to remove the catheter remove both
  the needle and catheter as one unit
• When dc an epidural catheter use steady pressure
  never jerk the catheter
• If difficulty is encountered change the patients
  positions (i.e. fetal position) to maximize the
  intervertebral space

108
Shearing Off the Tip of the Epidural Catheter

• If tip breaks off deep in the epidural space
  leave it and observe for complications
• If tip breaks off in the superficial tissue it
  should be surgically removed
• A remnant of epidural catheter superficially can
  lead to infection

109
Complications Associated With Medication Toxicity

• Systemic toxicity (covered earlier)
• Transient neurological symptoms
• Cauda equina syndrome

110
Transient Neurological Symptoms

• Described in 1993
• Most common after spinal anesthesia/rare for it
  to occur with epidural anesthesia
• Symptoms include LBP with radiation to the legs
• Sx occur after anesthetic has regressed and
  normal sensation has occurred
• Sx occur from 1-24 hours after normal sensation
• Almost any local anesthetic can cause TNS

111
Transient Neurological Symptoms- Associated Local
Anesthetics

• Lidocaine
• Tetracaine
• Bupivacaine
• Mepivacaine
• Prilocaine
• Procaine
• Ropivacaine

112
Transient Neurological Symptoms- Associated Local
Anesthetics

• Most common local anesthetic to cause TNS is
  lidocaine
• Most in the anesthesia community have abandoned
  lidocaine as a spinal anesthetic
• Leaves us with few good choices
• Procaine often too short lived
• Prilocaine has a high incidence of nausea and
  vomiting
• Mepivacaine has similar profile to lidocaine for
  both duration and incidence of TNS

113
Transient Neurological Symptoms

• Unknown mechanism of action
• Theorized that lidocaine is more neurotoxic to
  the unsheathed nerve

114
Transient Neurological Symptoms-Contributing
Factors

• Lithotomy position may be due to stretching of
  the lumbrosacral nerve roots and decreased
  perfusion
• Early ambulation after the spinal reason not
  elucidated
• Treatment is symptomatic and generally is short
  lived

115
Cauda Equina Syndrome

• Associated with spinal catheters and 5 lidocaine
• Differs from TNS in that it is permanent and
  associated with sphincter dysfunction, sensory
  and motor deficits, and paresis

116
Cauda Equina Syndrome

• Generally appears in a peripheral nerve pattern
  and may be due to misdistribution of the
  hyperbaric lidocaine

117
Cauda Equina Syndrome

• Neurotoxicity of local anesthetics is as follows
• Lidocainetetracaine gt bupivacaine gt ropivacaine
• Pain is similar to nerve root compression
• Has been reported after single shot spinals as
  well as rarely after epidural anesthesia

118
Analyzing Complications of Spinal and Epidural
Anesthesia

• Sweden
• 1990-1999
• Reviewed 1,260,000 spinals and 400,000 epidurals
  (half of which were for OB)
• Overall incidence of complications were 127 out
  of 1,660,000.

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
119
Analyzing Complications of Spinal and Epidural
Anesthesia

• Incidence for spinal anesthetics 120,000-30,000
• Incidence for epidural in OB was 125,000
• Incidence for non OB epidural was 13,600
• (this differs from US experience)

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
120
Analyzing Complications of Spinal and Epidural
Anesthesia- Risk Factors

• LMWH administered within 10 hours before a spinal
  or epidural or removing a catheter 2 hours before
  treatment
• Disease that cause coagulation problems such as
  renal/liver, OB syndrome with hemolysis, elevated
  liver enzymes, low platelets
• Ankylosing Syndrome

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
121
Analyzing Complications of Spinal and Epidural
Anesthesia- Risk Factors

• Spinal deformity
• Trauma while during the block
• Osteoporosis

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
122
Analyzing Complications of Spinal and Epidural
Anesthesia

• Most complications seen with orthopedic surgery
  followed by general surgery and then urology
• Complications higher after epidural anesthesia
  when compared to spinal anesthesia
• Patients with cauda equina syndrome, traumatic
  cord injury, and paraplegia had a 100 of
  permanent injury.

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
123
Analyzing Complications of Spinal and Epidural
Anesthesia- The take home

• Complications occur 4-5 times more frequently
  after spinal anesthesia when compared to epidural
• OB population had a lower incidence of
  complications compared to non ob female
  population
• Osteoporosis is now a risk factor
• Severe complications have a high rate of being
  permanent

Moen V, Dahlgren N, Irestedt L. Severe
neurological complications after central
neuraxial blockade in Sweden 1990-1999.
Anesthesiology. 2004 101 950-959.
124
Allergic Reactions

• Very low incidence with local anesthetics.
• Esters are more likely to cause reactions. They
  are metabolized into PABA (a known allergen).
• Methylparaben is a preservative used in some
  multi dose vials and is structurally similar to
  PABA. Should use preservative free local
  anesthetics.

125
Allergic Reactions

• Most reactions are related to vagal reactions,
  toxicity of local anesthetics, effects of
  epinephrine such as tachycardia, flushing, and
  tachypnea.
• Allergic reactions to anesthetics are rare.
  Propensity to cause allergic reactions are as
  follows muscle relaxantsgt thiopental gt propofol gt
  etomidate ketamine benzodiazepines gt local
  anesthetics

126
Allergic Reactions

• Anaphylactic reactions involve in a number of
  mediators that result in an exaggerated response.
• Airway- angioedema of upper airway, bronchospasm,
  and edema of the lower airway. Signs and
  symptoms include bronchospasm, cough, dyspnea,
  pulmonary edema, laryngeal edema, and hypoxia.
•  
• Vascular- increased permeability allows edema to
  occur resulting in hypovolemia and shock.
  Primary symptom will be hypotension and shock.
•  
• Heart- hypoperfusion and hypoxemia results in
  arrhythmias and myocardial ischemia. Coronary
  vasoconstriction may occur. Tachycardia and
  arrhythmias are common.
•  
• Other vital organs- resulting shock and lactic
  acidosis leads to additional ischemic trauma.
•  
• The effect of mediators will manifest
  dermatologically as urticaria, facial edema, and
  pruritus.

127
Allergic Reactions

• Treatment includes the following
• Stop the administration of the suspected
  medication
• Administer 100 O2 and consider intubation if the
  patient is not already intubated.
• Epinephrine administered in doses of 0.01-0.5 mg
  IV or IM
• Administer fluids rapidly to combat the
  hypovolemia and shock (1-2 L of crystalloid)
• Diphenhydramine in a dose of 50-75 mg IV
• Rantidine or cimetidine IV
• Hydrocortisone up to 200 mg IV or alternatively
  methylprednisolone in a dose of 1-2 mg/kg IV.

128
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