Donald H. Lambert

1
Spinal - Epidural - Combined Spinal Epidural

• Donald H. Lambert
• Boston, Massachusetts

http//www.debunk-it.org
2
Spinal - Epidural - Combined Spinal Epidural

• Donald H. Lambert
• Boston, Massachusetts

http//www.debunk-it.org
3
(No Transcript)
4
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

5
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

6
(No Transcript)
7
(No Transcript)
8
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

9
Spinal Anesthesia Agents
10
(No Transcript)
11
(No Transcript)
12

• The dosing in this study was 10 mg, 15 mg, and 20
  mg of bupivacaine
• The lowest dose limited spread
• The lowest dose also resulted in more failures
  than the higher doses.

13
(No Transcript)
14
(No Transcript)
15
(No Transcript)
16
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

22
(No Transcript)
23

• The effect of baricity on the distribution of
  bupivacaine in spinal model
• In spite of the crudeness of this model, the
  levels of anesthesia predicted by the model are
  remarkably similar to the levels of anesthesia
  observed in patients

Hyperbaric
Isobaric
Hypobaric
24
Hyperbaric
Isobaric
Hypobaric
25
(No Transcript)
26
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

27
Spinal Anesthesia

• Dosing will affect
• Spread
• Duration
• Quality of Anesthesia
• That is, the need for supplemental IV medication

28

• The duration of anesthesia with bupivacaine is
  dependent on the dose
• Regression to T10 and T12 is similar despite the
  difference in concentration so long as the dose
  (mg) is the same
• There is a tendency for the analgesia to be
  shorter with the 0.5 v. 0.75 bupivacaine
• With lidocaine the motor block wears off more
  quickly with 1.5 v. 5 when equal doses are
  given.

29
(No Transcript)
30
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

31
Spinal Anesthesia

• I have been doing spinal anesthesia for 25 years
• I spent the first 10 years trying to control the
  level of spinal anesthesia
• I have failed
• I have given up trying
• If you know how to control the level of spinal
  anesthesia please tell me how it is done

32
Dosing Guidelines

• Based on the spinal canal model (and many years
  in the trench)
• Hyperbaric solutions extend into the thoracic
  region
• Isobaric solution remain in the lumbar region
• I give hyperbaric solutions for operations above
  the L1 dermatome and isobaric solutions for those
  below

Hyperbaric
Isobaric
33
Dosing Guidelines

• Hernia operations and those operations whose
  innervation is by nerves above L1
• HYPERBARIC
• Those operations whose innervation is by nerves
  below L1 (pretty much all lower extremity
  operation including hip operations)
• ISOBARIC

34
(No Transcript)
35
CHOOSING A LOCAL ANESTHETIC FOR SPINAL
ANESTHESIABASE DECISION ON THE DURATION OF THE
OPERATION
36
(No Transcript)
37
CHOOSING A LOCAL ANESTHETIC FOR SPINAL
ANESTHESIAGIVE ENOUGH TO PROVIDE ADEQUATE
ANESTHESIA
? CHLOROPRACAINE, ? ROPIVACAINE
38
Isobaric Spinal Anesthesia

• Epidural Bupivacaine
• It says right on the bottle Not for spinal
  anesthesia
• What is the value or wisdom behind using that
  agent?
• It works great and I have used it since the
  1980s.
• I know of no reports of complications associated
  with using it.
• Litigation for the off-labeled use of a drug has
  not appeared in the ASA closed claims database.
• Who would know?
• Unless you wrote on your anesthesia record, I
  used the bupivacaine that is not for spinal
  anesthesia.

39
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

40
Spinal Anesthesia

• Complications
• Cardiac arrest
• Hypotension
• Headache
• Nerve injury

41
Unexpected cardiac arrest during spinal
anesthesia a closed claims analysis of
predisposing factors
Caplan, R A et al. Unexpected cardiac arrest
during spinal anesthesia a closed claims
analysis of predisposing factors. Anesthesiology
1988685-11
42
Unexpected cardiac arrest during spinal
anesthesia a closed claims analysis of
predisposing factors
Caplan, R A et al. Unexpected cardiac arrest
during spinal anesthesia a closed claims
analysis of predisposing factors. Anesthesiology
1988685-11 Caplan, R A et al. Injuries
Associated with Regional Anesthesia in the 1980s
and 1990s A Closed Claims Analysis.
Anesthesiology. 2004101143-152
43
Unexpected cardiac arrest during spinal
anesthesia a closed claims analysis of
predisposing factors
Caplan, R A et al. Unexpected cardiac arrest
during spinal anesthesia a closed claims
analysis of predisposing factors. Anesthesiology
1988685-11
44
Unexpected cardiac arrest during spinal
anesthesia a closed claims analysis of
predisposing factors
Initial Clues of Impending Arrest
Caplan, R A et al. Unexpected cardiac arrest
during spinal anesthesia a closed claims
analysis of predisposing factors. Anesthesiology
1988685-11
45
Unexpected cardiac arrest during spinal
anesthesia a closed claims analysis of
predisposing factors

• Factors Predisposing to Asystole
• High level
• Loss of Cardiac Sympathetic Stimulation
• Unopposed Vagal Tone
• Decreased Venous Return
• Empty Left Ventricle
• Activation of Intracardiac Reflexes
• ? So-called Bezold-Jarisch Reflex or the
  so-called Vaso-vagal Syncope

Caplan, R A et al. Anesthesiology 1988685-11
and Mackey, D C, et al. Anesthesiology
198970866-868
46
Cardiac arrest during spinal anesthesia

• How can this be prevented and/or treated?
• Maintain venous return at all cost
• Use epinephrine at the first sign of cardiac
  arrest

Keats, A. S. Anesthesia mortality--a new
mechanism.Anesthesiology 1988682-4.
47
Cardiac Arrest During Neuraxial Anesthesia
Frequency and Predisposing Factors Associated
with Survival
Sandra L. Kopp, et al Anesth Analg 2005 100
855-65
48
Acta Anaesthesiol Scand 1997 41 445-5Severe
complications associated with epidural and spinal
anaesthesias in Finland 1987-1993. A study based
on patient insurance claims Aromaa U, Lahdensuu
M, Cozanitis DA
49
Spinal Anesthesia Complications

• Hypotension (happens!)

But, if you want to know something it happens
also when I do general anesthesia!!
50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
The Two Components of Spinal Headache

• There must have been a lumbar puncture
• The headache is related to posture
• Worst when standing or sitting
• Gone or improved with recumbence

56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
(No Transcript)
60
Effect of Age on the Incidence of Spinal Headache
This and AARP discounts are two of the few
advantages to aging!
Vandam and Dripps, JAMA 1956161586-591
61
There is a lower incidence of spinal headache in
older patients

• One of the few advantages of aging!

62
(No Transcript)
63
(No Transcript)
64
(No Transcript)
65
(No Transcript)
66
(No Transcript)
67
(No Transcript)
68
(No Transcript)
69
How Safe are Spinals?

• TNS/TRI

• Most frequent with lidocaine (10-34 incidence)
• More frequent with lithotomy position and knee
  arthroscopy
• VAS pain score averages 6 out of 10
• Many rate the pain worse than their incision
• Can last up to three days
• Least frequent with bupivacaine

70
How Safe are Spinals?
71
(No Transcript)
72
Spinal Anesthesia

• Is there a reasonable alternative to lidocaine?
• What are the possibilities?
• Procaine
• ? Chloroprocaine (non-neurotoxic in isolated
  nerve)
• recent data in rats indicates neural toxicity
  with i.t. infusion
• Prilocaine (low incidence of TRI, but neurotoxic
  in rat)
• Mepivacaine (same incidence of TRI as with
  lidocaine)
• Low dose bupivacaine
• ? Ropivacaine

73
(No Transcript)
74
Spinal Anesthesia

• Advantages v. Disadvantages
• Pharmacology of spinal agents
• Addition of a vasoconstrictor
• Baricity
• Dosing
• Complications

75
EPIDURAL ANESTHESIA

• Advantages v. Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

76
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

77
(No Transcript)
78
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

79
(No Transcript)
80
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

81
(No Transcript)
82
(No Transcript)
83
(No Transcript)
84
(No Transcript)
85
(No Transcript)
86
(No Transcript)
87

• Through the years many methods to locate the
  epidural space have come and gone.
• This attests to the difficulty associated with
  the performance of epidural anesthesia.
• The two methods that have stood the test of time
  appear to be loss of resistance to injection of
  air or saline.

88
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

89
EPIDURAL ANESTHESIA AGENTS
DRUG CONC. DOSE VOLUME DURATION () (mg) (ml) (m
in) CHLOROPROC. 2 - 3 300 - 900 15 - 30 30 -
90 LIDOCAINE 1 - 2 150 - 500 15 - 30 60 -
180 MEPIVACAINE 1 - 2 150 - 500 15 - 30 60 -
180 PRILOCAINE 1 - 3 150 - 600 15 - 30 60 -
180 ROPIVACAINE 0.5 - 1.0 75 - 300 15 - 30 180
- 300 BUPIVACAINE 0.25 - 0.75 37.5 - 225 15 -
30 180 - 300 LEVOBUPIV. 0.25 - 0.75 37.5 - 225 15
- 30 180 - 300 ETIDOCAINE 1 - 1.5 150 - 300 15 -
30 180 - 300
90
(No Transcript)
91
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

92
(No Transcript)
93
Truisms on Dose

• The more you put in
• The quicker it comes on
• The better the block
• The longer it lasts
• The more you put in
• The more likely are you to cause toxicity

94
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

95
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

96
(No Transcript)
97
(No Transcript)
98

• The are many potential sites where epidural local
  anesthetics can act.
• The highest concentrations of local anesthetic
  are found in the CSF and nerve roots.
• The lowest concentrations are found in the dorsal
  root ganglia and the substance of the spinal
  cord.
• All sites likely contribute to the mechanism of
  epidural anesthesia, but the most likely
  conclusion is that the epidural anesthesia comes
  about by an intrathecal action.

99
(No Transcript)
100
(No Transcript)
101

• The largest and most difficult nerve root to
  block with epidural anesthesia is S1.
• The S1 root is the one which is most likely to be
  missed or poorly anesthetized.

102
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

103
Effect of Epinephrine on Peak Venous Plasma Level
with Epidural Anesthesia

• The more vasodilating agents - mepivacaine and
  lidocaine show the greatest epinephrine effect.
• The lack of effect with prilocaine may be due to
  its good diffusion.
• The lack of effect with etidocaine and
  bupivacaine due to their avid binding to lipids.

104
(No Transcript)
105
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

106
(No Transcript)
107
Cardiovascular Toxicity
HYPERTENSION - TACHYCARDIA OWING TO CNS
EXCITATION NEGATIVE INOTROPY DECREASED CARDIAC
OUTPUT MILD - MODERATE HYPOTENSION PERIPHERAL
VASODILATATION PROFOUND HYPOTENSION SINUS
BRADYCARDIA CONDUCTION DEFECTS
VENTRICULAR ARRYTHMIAS CARDIOVASCULAR
COLLAPSE
108

• Low doses of epidural local anesthetics have a
  CNS stimulating affect that counteracts vascular
  depression.
• With higher local anesthetic doses,
  cardiovascular depression is more apparent.
• Epinephrine contributes to vascular depression by
  its beta effect, which lower peripheral vascular
  resistance.
• Hypovolemia contributes to cardiovascular
  collapse (vaso-depressor syncope?).
• The deleterious effect of hypovolemia is
  counteracted by the addition of epinephrine to
  the local anesthetic.

LEVEL T5 T1 T2-3 T5 T5 Lido (ug/ml) lt4 lt4 gt4 lt4 lt4
Epinephrine 0 0 0 Hypovolemia 0
0 0 0
109
(No Transcript)
110
LEVEL T5 T1 T2-3 T5 T5 T5 Lido (ug/ml) lt4 lt4 gt4 lt4
lt4 lt4 Epinephrine 0 0 0
0 Hypovolemia 0 0 0 0
111
(No Transcript)
112
(No Transcript)
113
The Two Components of Spinal Headache

• There must have been a lumbar puncture
• The headache is related to posture
• Worst when standing or sitting
• Gone or improved with recumbence

114
Accidental puncture during labor epidural

• About a 1 chance of less
• About 60 will develop a headache
• About 70 will require a blood patch

115
(No Transcript)
116
(No Transcript)
117
(No Transcript)
118
(No Transcript)
119
(No Transcript)
120
(No Transcript)
121
FDA WARNING ON LOW MOLECULAR WEIGHT HEPARIN
Standard LMWH Mean Mol. Wt. 12000-15000 4000-6500
Saccharide units 40 - 50 13 - 20 Anti X-a Anti
II-a Activity 11 21 to 41 Plasma Protein
Binding High Low Endothelium Binding Yes
Weakly Dose Dependent Clearance Yes No Small
Dose Bio-availability Poor Good Platelet
Inhibition Strong Moderate Increases Vascular
Permeability Yes No
122
Guidelines for Regional Anesthesia in the
Anticoagulated Patient

• See Consensus Statement at the ASRA Web site

http//www.asra.com/items_of_interest/consensus_st
atements/
123
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

124
Components of an Epidural Test Dose

• Cause a detectable increase the heart rate
• Cause detection of a spinal injection but not
  produce a total spinal
• Three ml of 1.5 lidocaine with epinephrine 5
  ug/ml will do both
• Unless the patient is beta blocked

125
Test Dose

• Used to prevent intravascular injection of local
  anesthetic
• Epinephrine most frequently advocated and most
  extensively studied
• 15 ug of epinephrine produces a tachycardia
  within 20 seconds
• Reliability diminished by beta blockade, aging,
  general or combined general-epidural anesthesia

Mulroy, MF RAPM 27556-5612002
126
Test Dose
Criteria for Positive Epinephrine Test
Dose Patient under age 60, awake, HR increase gt
20 bpmnot on beta blocker Beta blockade SBP
increase gt 15 torr Age over 60 SBP increase gt 15
torr HR increase gt 9 bpm General Anesthesia SBP
increase gt 13 torr HR increase gt 8 bpm
All changes in the first 120 seconds of injection
Mulroy, MF RAPM 27556-5612002
127
Test Dose

• When epinephrine is not practical
• Use moderate doses of local anesthetic while
  monitoring for CNS effects
• 100 mg of lidocaine or chloroprocaine
• 25 mg of bupivacaine
• Requires non pre-medicated patient
• Medication with midazolam will interfere

Mulroy, MF RAPM 27556-5612002
128
(No Transcript)
129
Test Dose
From Mulroy, MF RAPM 27556-5612002
130
Local Anesthetic ToxicityRate of Injection

• Slow rates of injection are less likely to result
  in systemic toxicity
• Intermittent injections, at slow rates will
  lessen further the likelihood of systemic
  toxicity
• These two steps, in my opinion, are better than a
  test dose of local anesthetic with epinephrine as
  tracer

131
Test Dose Quiz

• Epidural anesthesia for cesarean delivery is
  planned for a 30-year-old woman in labor. She has
  preeclampsia and takes propranolol for mitral
  valve prolapse. A test dose of 3 ml of 2
  lidocaine containing 15 ?g of epinephrine is
  administered, and no change in heart rate is
  noted by palpation of the pulse. Prior to
  injection of more local anesthetic, blood is
  freely aspirated from the catheter. Explanations
  for failure of the intravenous test dose include
• (1) The pain of labor masked the change
  usually seen with the test dose
• (2) Pre-existing beta-adrenergic blockade
  blunted the tachycardia from the
  intravenous epinephrine
• (3) Changes in pulse rate were too brief to be
  noted by palpation of the
• pulse
• (4) Preeclampsia decreased the sensitivity to
  exogenously administered catecholamines

132
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

133
Comparing spinal to epidural

• Spinal easier to do
• No chance systemic toxicity
• Increased risk of neural toxicity
• Duration too short
• Low incidence of spinal headache

• Epidural more difficult
• Systemic toxicity possible
• Less chance neural toxicity except with certain
  agents and accidental spinal injection
• Unlimited duration
• Incidence of spinal headache about the same as
  spinal

134
(No Transcript)
135
(No Transcript)
136
(No Transcript)
137
EPIDURAL ANESTHESIA

• Advantages
• Disadvantages
• Technique
• Pharmacology of Specific Agents
• Effect of Dose
• Mechanism of Action
• Addition of a Vasoconstrictor
• Complications
• Test Dose
• Comparison with Spinal

138
(No Transcript)
139
Good luck with your exam!

• If you still have unanswered questions
• OR
• If you have answers you want questioned

You can contact me (no bunk)donlam_at_debunk-it.org
I will try to post these presentations on a web
sitehttp//www.debunk-it.org (Education Corner)
Dont for get the dash between debunk and it
140
Components of an Epidural Test Dose

• Cause a detectable increase the heart rate
• Cause detection of a spinal injection but not
  produce a total spinal
• Three ml of 1.5 lidocaine with epinephrine 5
  ug/ml will do both
• Unless the patient is beta blocked