Donald H. Lambert

Boston, Massachusetts

http://www.debunk-it.org

Spinal - Epidural - Spinal - Epidural - [Combined Spinal Epidural][Combined Spinal Epidural]

Advantages of Spinal AnesthesiaAdvantages of Spinal Anesthesia

Technically easy Objective end-point Rapid onset Profound sensory and motor block Low potential for systemic toxicity

Disadvantages of Spinal AnesthesiaDisadvantages of Spinal Anesthesia

Limited duration Limited sensory and motor separation “Hypotension” Potential neuro-toxicity Headache

IndicationsIndications

Any operation in the lower abdomen and below

Absolute ContraindicationsAbsolute Contraindications

Patient refusal Uncorrected hypovolemia Uncorrected coagulopathy Infection at site of injection Increased intracranial pressure

Relative ContraindicationsRelative Contraindications

Some neurologic diseases Bacteremia Deformities that preclude doing an LP easily

Positioning for the Spinal or EpiduralPositioning for the Spinal or Epidural

Two choices Sitting Lateral decubitus (recumbent)

ABSOLUTELY NO RITUALS!

Spinal AnesthesiaSpinal Anesthesia

Dosing will affect Spread Duration Quality of Anesthesia

That is, the need for supplemental IV medication

Spinal Anesthesia AgentsSpinal Anesthesia AgentsAgent Conc. (%) Dose Gluc. Duration

Proc. 10 100-200 30-90Chlorop. 2 40-120 30-90Lido. 1.5 – 5 30-100 7.5 30-90Mep. 4 40-80 9 30-90Prilo. ? ? ? ?Ropiv. ? ? ? ?Dibu. 0.06-0.5 2.5-12 5 75-150Bupiv. 0.25-.75 5-22.5 8.25 75-150Tetra. 0.25-1 5-20 5 75-150

.

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.

Addition of a Vasoconstrictor

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

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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 of doing this) Hyperbaric solutions

extend into the thoracic region

Isobaric solution remain in the lumbar region

Hyperbaric

Isobaric I give hyperbaric

solutions for operations above the L1 dermatome and isobaric solutions for those below

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.”

Narcotic work here in the substantia gelatinosa

Local anesthetics work here in the nerve roots

Spinal AnesthesiaSpinal Anesthesia

Addition of narcotics Fentanyl (15-25 ug lasts a few hours) Sufentanil (10 - 20 ug lasts a few hours) Morphine (100 - 200 ug lasts 12-24 hours) Side effects (increase with increasing dose)

Nausea and vomiting Itching Respiratory depression

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

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

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 Needle Gauge on the Effect of Needle Gauge on the Incidence of Spinal HeadacheIncidence of Spinal Headache

Vandam and Dripps JAMA 1956;161:586-591

02468

1012141618

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16 19 20 22 24

Needle Gauge

Effect of Age on the Incidence of Spinal Headache

Vandam and Dripps, JAMA 1956;161:586-591

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2

4

6

8

10

12

14

16Pe

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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!

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

Neurologic injury associated with paresthesia or pain on injection is believed to be traumatic.

Neurologic injury not associate with paresthesia or pain on injection is believed to be due to local anesthetic toxicity.

Permanent Nerve Injury with Spinal Permanent Nerve Injury with Spinal AnesthesiaAnesthesia

Spinal is somewhat more dangerous in causing cardiac arrest and major nerve injury than epidural or general

Epidural has a neurological injury rate similar to spinal but the injuries are different Epidural are associated with hematoma and

compressive nerve injury (? owing to volume) Spinals are associated with local anesthetic toxicity

Major Complication of Spinal AnesthesiaMajor Complication of Spinal Anesthesia

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

100 m

g

150 m

g

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

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.

0

1

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3

4

5

Pla

sm

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on

c.

(ug

/ml)

M ipiv500 mg

Lido400 mg

Prilo400 mg

Etido300 mg

Bupiv150 mg

Plain Epi - 5ug/ml

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

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 or 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/

Components of an Components of an Epidural Test DoseEpidural 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

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

Test DoseTest Dose

From 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

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

Questions?Questions?

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