Donald H. Lambert Boston, Massachusetts Spinal - Epidural - [Combined Spinal Epidural]
Donald H. Lambert Boston, Massachusetts Spinal - Epidural - [Combined Spinal Epidural]
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Transcript of Donald H. Lambert Boston, Massachusetts Spinal - Epidural - [Combined Spinal Epidural]
Donald H. Lambert
Boston, Massachusetts
http://www.debunk-it.org
Spinal - Epidural - Spinal - Epidural - [Combined Spinal Epidural][Combined Spinal Epidural]
Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
Spinal Anesthesia AgentsSpinal Anesthesia Agents
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.
Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
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
Hyp
erbari
cIsob
aric
Hyp
obari
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Hyp
erbari
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aric
Hyp
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Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
Spinal AnesthesiaSpinal Anesthesia
Dosing will affect Spread Duration Quality of Anesthesia
That is, the need for supplemental IV medication
Spinal AnesthesiaSpinal 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
Dosing GuidelinesDosing 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
Dosing GuidelinesDosing 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
CHOOSING A LOCAL ANESTHETIC FOR CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIASPINAL ANESTHESIA
BASE DECISION ON THE BASE DECISION ON THE DURATIONDURATION OF OF THE OPERATIONTHE OPERATION
CHOOSING A LOCAL ANESTHETIC FOR CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIASPINAL ANESTHESIA
GIVE ENOUGH TO PROVIDE GIVE ENOUGH TO PROVIDE ADEQUATEADEQUATE ANESTHESIAANESTHESIA
BARICITY PROC. LIDO. BUPIV. TETRA.ISOBARIC 80 mg 60 mg 15 mg 15 mgHYPERBARIC 80 mg 60 mg 15 mg 15 mg
? CHLOROPRACAINE, ? ROPIVACAINE
Isobaric Spinal AnesthesiaIsobaric 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 1980’s. 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.”
Spinal AnesthesiaSpinal Anesthesia
Advantages v. Disadvantages Pharmacology of spinal agents Addition of a vasoconstrictor Baricity Dosing Complications
Spinal AnesthesiaSpinal Anesthesia
Complications Cardiac arrest Hypotension Headache Nerve injury
Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors
1988 2004
Number of Claims 900 5,047
Number of Arrests 14 (1.5%) 68 (1.3%)
Mean Age 36 42
ASA Physical Status I - II I - II
Caplan, R A; et al. Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors. Anesthesiology 1988;68:5-11
Caplan, R A; et al. Injuries Associated with Regional Anesthesia in the 1980s and 1990s: A Closed Claims Analysis. Anesthesiology. 2004;101:143-152
Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors
Local Anesthetic Tetracaine
Dose 6 - 14 mg
Maximum Level T4
Time of Arrest 12 - 78 minutes
Caplan, R A; et al. Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors. Anesthesiology 1988;68:5-11
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 1988;68:5-11
1st Clue 2nd Clue CombinedClues
Bradycardia 7 2 9
Hypotension 2 6 8
Cyanosis 4 3 7
LOC 1 1 2
Asystole 0 2 2
Initial Clues of Impending ArrestInitial Clues of Impending Arrest
Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors
Caplan, R A; et al. Anesthesiology 1988;68:5-11 and Mackey, D C, et al. Anesthesiology 1989;70:866-868
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
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 1988;68:2-4.
Sandra L. Kopp, et al Anesth Analg 2005; 100: 855-65
Cardiac Arrest During Neuraxial Anesthesia: Frequency and
Predisposing Factors Associated with Survival
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
Spinal Anesthesia ComplicationsSpinal Anesthesia Complications
Hypotension (happens!)
But, if you want to know something… it happens also
when I do general anesthesia!!
Incidence and risk factors for side effects ofspinal anesthesia in 952 patients
Hypotension in 314 (33%)
Bradycardia in 125 (13%)
Nausea in 175 (18%)
Vomiting in 65 (7%)
Dysrhythmia in 20 (2%)
Carpenter, RL, et al. Anesthesiology 1992;76:906
Reduction of side effects during spinalanesthesia
Minimize peak block height
Perform lumbar puncture at or below L3-L4
Avoid vasoconstrictors
Avoid procaine
Carpenter, RL, et al. Anesthesiology 1992;76:906
The Two Components The Two Components of Spinal Headacheof 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
Effect of Age on the Incidence of Spinal Headache
Vandam and Dripps, JAMA 1956;161:586-591
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10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89
Age
This and AARP discounts are two of the few advantages to aging!
Spinal Anesthesia ComplicationsSpinal Anesthesia Complications
Nerve injury
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
How Safe are Spinals?How Safe are Spinals?
TNS/TRI
How Safe are Spinals?How Safe are Spinals?
Spinal AnesthesiaSpinal 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
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
EPIDURAL ANESTHESIA AGENTSEPIDURAL ANESTHESIA AGENTS
DRUG CONC. DOSE VOLUME DURATION(%) (mg) (ml) (min)
CHLOROPROC. 2 - 3 300 - 900 15 - 30 30 - 90LIDOCAINE 1 - 2 150 - 500 15 - 30 60 - 180MEPIVACAINE 1 - 2 150 - 500 15 - 30 60 - 180PRILOCAINE 1 - 3 150 - 600 15 - 30 60 - 180ROPIVACAINE 0.5 - 1.0 75 - 300 15 - 30 180 - 300BUPIVACAINE 0.25 - 0.75 37.5 - 225 15 - 30 180 - 300LEVOBUPIV. 0.25 - 0.75 37.5 - 225 15 - 30 180 - 300ETIDOCAINE 1 - 1.5 150 - 300 15 - 30 180 - 300
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
Truisms on DoseTruisms 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
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
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.
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
Effect of Epinephrine on Peak VenousEffect of Epinephrine on Peak VenousPlasma Level with Plasma Level with Epidural Epidural AnesthesiaAnesthesia
The more “vasodilating”agents - mepivacaineand lidocaine show thegreatest epinephrineeffect.
The lack of effect withprilocaine may be due toits “ good diffusion.”
The lack of effect withetidocaine andbupivacaine due to theiravid binding to lipids.
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Pla
sm
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on
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(ug
/ml)
M ipiv500 mg
Lido400 mg
Prilo400 mg
Etido300 mg
Bupiv150 mg
Plain Epi - 5ug/ml
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
Cardiovascular ToxicityCardiovascular ToxicityHYPERTENSION - 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
Low doses of epidural localanesthetics have a CNSstimulating affect thatcounteracts vascular depression.
With higher local anestheticdoses, cardiovascular depressionis more apparent.
Epinephrine contributes tovascular depression by its betaeffect, which lower peripheralvascular resistance.
Hypovolemia contributes tocardiovascular collapse (vaso-depressor syncope?).
The deleterious effect ofhypovolemia is counteracted bythe addition of epinephrine tothe local anesthetic.
-40
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MAP PVR CO
LEVEL T5 T1 T2-3 T5 T5
Lido (ug/ml) <4 <4 >4 <4 <4
Epinephrine 0 0 0 + +
Hypovolemia 0 0 0 0 +
-40
-30
-20
-10
0
10
20
30
40
50
MAP PVR CO
LEVEL T5 T1 T2-3 T5 T5 T5
Lido (ug/ml) <4 <4 >4 <4 <4 <4
Epinephrine 0 0 0 + 0 +
Hypovolemia 0 0 0 0 + +
The Two Components The Two Components of Spinal Headacheof 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
Accidental puncture Accidental puncture during labor epiduralduring labor epidural
About a 1% chance of less
About 60% will develop a headache
About 70% will require a blood patch
Guidelines for Regional Anesthesia in Guidelines for Regional Anesthesia in the Anticoagulated Patientthe Anticoagulated Patient
See Consensus Statement at the ASRA Web site:
http://www.asra.com/items_of_interest/consensus_statements/
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
Test DoseTest 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 27:556-561;2002
Test DoseTest 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 27:556-561;2002
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ase
1970s 1980s 1990s
IV injection
Death
No test dose
Mulroy, MF RAPM 27:556-561;2002
Local Anesthetic ToxicityLocal Anesthetic ToxicityRate of InjectionRate 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
Test Dose QuizTest Dose QuizEpidural 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
EPIDURAL ANESTHESIAEPIDURAL ANESTHESIA
Advantages Disadvantages Technique Pharmacology of Specific Agents Effect of Dose Mechanism of Action Addition of a Vasoconstrictor Complications Test Dose Comparison with Spinal
Comparing spinal to epiduralComparing 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
Good luck with your exam!Good luck with your exam!
If you still have unanswered questions
OR
If you have answers you want questioned
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