Donald H. Lambert Boston, Massachusetts Spinal - Epidural - [Combined Spinal Epidural]

Advantages of Spinal Anesthesia l Technically easy l Objective end-point l Rapid onset l Profound sensory and motor block l Low potential for systemic toxicity

Disadvantages of Spinal Anesthesia l Limited duration l Limited sensory and motor separation l “Hypotension” l Potential neuro-toxicity l Headache

Indications Any operation in the lower abdomen and below

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

Relative Contraindications l Some neurologic diseases l Bacteremia l Deformities that preclude doing an LP easily

Positioning for the Spinal or Epidural l Two choices Sitting Lateral decubitus (recumbent)

ABSOLUTELY NO RITUALS!

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

Spinal Anesthesia Agents

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

Spinal Anesthesia Agents

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

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

Addition of a Vasoconstrictor

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

l The effect of baricity on the distribution of bupivacaine in spinal model l 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

Hyperbaric Isobaric Hypobaric

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

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

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

Dosing Guidelines l 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 l I give hyperbaric solutions for operations above the L1 dermatome and isobaric solutions for those below

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

CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIA BASE DECISION ON THE DURATION OF THE OPERATION

CHOOSING A LOCAL ANESTHETIC FOR SPINAL ANESTHESIA GIVE ENOUGH TO PROVIDE ADEQUATE ANESTHESIA ? CHLOROPRACAINE, ? ROPIVACAINE

Isobaric Spinal Anesthesia l Epidural Bupivacaine It says right on the bottle: “Not for spinal anesthesia” What is the value or wisdom behind using that agent? u It works great and I have used it since the 1980’s. u I know of no reports of complications associated with using it. u Litigation for the off-labeled use of a drug has not appeared in the ASA closed claims database. Who would know? u 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 Anesthesia l Addition of narcotics Fentanyl (15-25 ug lasts a few hours) Sufentanil ( ug lasts a few hours) Morphine ( ug lasts hours) Side effects (increase with increasing dose) u Nausea and vomiting u Itching u Respiratory depression

Spinal Anesthesia l Advantages v. Disadvantages l Pharmacology of spinal agents l Addition of a vasoconstrictor l Baricity l Dosing l Complications

Spinal Anesthesia l Complications Cardiac arrest Hypotension Headache Nerve injury

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 Caplan, R A; et al. Injuries Associated with Regional Anesthesia in the 1980s and 1990s: A Closed Claims Analysis. Anesthesiology. 2004;101:

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

Cardiac arrest during spinal anesthesia l 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: Cardiac Arrest During Neuraxial Anesthesia: Frequency and Predisposing Factors Associated with Survival

Acta Anaesthesiol Scand 1997; 41: Severe complications associated with epidural and spinal anaesthesias in Finland A study based on patient insurance claims Aromaa U, Lahdensuu M, Cozanitis DA

Spinal Anesthesia Complications Hypotension (happens!) But, if you want to know something… it happens also when I do general anesthesia!!

The Two Components of Spinal Headache l There must have been a lumbar puncture l The headache is related to posture Worst when standing or sitting Gone or improved with recumbence

Effect of Needle Gauge on the Incidence of Spinal Headache Vandam and DrippsJAMA 1956;161:

Effect of Age on the Incidence of Spinal Headache Vandam and Dripps, JAMA 1956;161: 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? n 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 Anesthesia

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 u Epidural are associated with hematoma and compressive nerve injury (? owing to volume) u Spinals are associated with local anesthetic toxicity Major Complication of Spinal Anesthesia

Eisenach, James C. Regional Anesthesia: Vintage Bordeaux (and Napa Valley) Anesthesiology 1997;87: l Editorial on Auroy’s study: “Spinal anesthesia appears in this study to be more dangerous than other regional anesthesia techniques.” u “Neurologic injury is two- to threefold greater with spinal than with other regional anesthetic techniques.” Nerve Injury Still Occurring

How Safe are Spinals?

Spinal Anesthesia l Is there a reasonable alternative to lidocaine? l What are the possibilities? Procaine ? Chloroprocaine (non-neurotoxic in isolated nerve) u 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 ANESTHESIA l Advantages l Disadvantages l Technique l Pharmacology of Specific Agents l Effect of Dose l Mechanism of Action l Addition of a Vasoconstrictor l Complications l Test Dose l Comparison with Spinal

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

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

EPIDURAL ANESTHESIA AGENTS DRUGCONC.DOSE VOLUMEDURATION (%)(mg)(ml)(min) CHLOROPROC LIDOCAINE MEPIVACAINE PRILOCAINE ROPIVACAINE BUPIVACAINE LEVOBUPIV ETIDOCAINE

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

100 mg 150 mg

Truisms on Dose l The more you put in  The quicker it comes on  The better the block  The longer it lasts l The more you put in The more likely are you to cause toxicity

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

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

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

LEVEL T5T1T2-3T5T5T5 Lido (ug/ml) 4<4<4<4 Epinephrine Hypovolemia

The Two Components of Spinal Headache l There must have been a lumbar puncture l The headache is related to posture Worst when standing or sitting Gone or improved with recumbence

Accidental puncture during labor epidural l About a 1% chance or less l About 60% will develop a headache l About 70% will require a blood patch

Guidelines for Regional Anesthesia in the Anticoagulated Patient See Consensus Statement at the ASRA Web site:

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

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

Test Dose l Used to prevent intravascular injection of local anesthetic l 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: ;2002

Test Dose l When epinephrine is not practical Use moderate doses of local anesthetic while monitoring for CNS effects u 100 mg of lidocaine or chloroprocaine u 25 mg of bupivacaine u Requires non pre-medicated patient u Medication with midazolam will interfere Mulroy, MF RAPM 27: ;2002

Test Dose From Mulroy, MF RAPM 27: ;2002

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

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

Comparing spinal to epidural l Spinal easier to do l No chance systemic toxicity l Increased risk of neural toxicity l Duration too short l Low incidence of spinal headache l Epidural more difficult l Systemic toxicity possible l Less chance neural toxicity except with certain agents and accidental spinal injection l Unlimited duration l Incidence of spinal headache about the same as spinal

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): I will try to post these presentations on a web site: (Education Corner) Don’t for get the “dash” between “debunk” and “it”

RULE N0. 1: YOUR ATTENDING IS ALWAYS RIGHT. RULE NO. 2: IF YOUR ATTENDING ISWRONG, SEE RULE NO. 1.

Eisenach, James C. Regional Anesthesia: Vintage Bordeaux (and Napa Valley) Anesthesiology 1997;87: l Editorial on Auroy’s study: “Spinal anesthesia appears in this study to be more dangerous than other regional anesthesia techniques.” u “The risk of cardiac arrest is five- to six fold greater than with other regional anesthetic techniques ” Cardiac Arrest Still Occurring

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

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 Initial Clues of Impending Arrest

Cardiac arrest during spinal anesthesia l 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.

* ”Regional Anesthesia” Cardiac Arrest Associated with Anesthesia (per 10,000)

l There appears to be two mechanisms for cardiac arrest during spinal anesthesia Spinal factors u Vaso-depressor syncope Factors other than the spinal u Blood loss u Cardiac events u Orthopedic manipulations Cardiac Arrest Associated with Anesthesia

Effect of Needle Gauge on the Incidence of Spinal Headache Vandam and DrippsJAMA 1956;161:

Spinal Anesthesia l Complications Cardiac arrest Hypotension Headache Nerve injury

l Two types Permanent u Cauda equina syndrome u Adhesive arachnoiditis Non-permanent u Transient radicular irritation Nerve Injury with Spinal Anesthesia

l Lidocaine spinal anesthesia was associated with 14.4 per 10,000 neurologic complications compared to 2.2 per 10,000 for bupivacaine spinal anesthesia. Auroy Y. et al. Major complications of regional anesthesia in France: The SOS Regional Anesthesia Hotline Service. Anesthesiology 2002; 97: Permanent Nerve Injury with Spinal Anesthesia

l In the cases [of cauda equina syndrome and paraparesis] after subarachnoid block, hyperbaric 5% lidocaine was used in eight cases, bupivacaine 0.5% in 11 cases, and in one case a mixture of both drugs was used. Moen V. et al: Anesthesiology 2004; 101: Permanent Nerve Injury with Spinal Anesthesia

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 u Epidural are associated with hematoma and compressive nerve injury (? owing to volume) u Spinals are associated with local anesthetic toxicity Major Complication of Spinal Anesthesia

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 Anesthesia

Eisenach, James C. Regional Anesthesia: Vintage Bordeaux (and Napa Valley) Anesthesiology 1997;87: l Editorial on Auroy’s study: “Spinal anesthesia appears in this study to be more dangerous than other regional anesthesia techniques.” u “Neurologic injury is two- to threefold greater with spinal than with other regional anesthetic techniques.” Nerve Injury Still Occurring

l Minor complications Transient neurologic symptoms (TNS) a.k.a. transient radicular irritation (TRI) Non-permanent Nerve Injury with Spinal Anesthesia

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 n TNS/TRI Non-permanent Nerve Injury with Spinal Anesthesia

The best alternative to lidocaine appears to be bupivacaine. u Lasts too long Other shorter acting substitutes have not caught on. u Procaine, mepivacaine, prilocaine, ropivacaine n TNS/TRI Non-permanent Nerve Injury with Spinal Anesthesia

Chloroprocaine (off label) is being rediscovered as a short acting spinal anesthetic. Series of ten articles by Dan Kopacz et al. in the last year (see Anesth Analg 2004 and 2005) u Comparable to lidocaine. u No TNS n TNS/TRI Non-permanent Nerve Injury with Spinal Anesthesia

The spinal anesthetic profile of 40 mg chloroprocaine compares favorably with the same dose of spinal lidocaine Lidocaine was associated with mild to moderate TNS in 7 of 8 subjects No subject complained of TNS with chloroprocaine Yoos JR, Kopacz DJ:. Anesth Analg 2005; 100: n TNS/TRI Non-permanent Nerve Injury with Spinal Anesthesia

Does General Anesthesia Cause Nerve Injury?

Questions? - Anesthesiology Forum