epidural anesthesia

Epidural AnesthesiaEpidural Anesthesia


Presentation divided into two sections:Presentation divided into two sections:

1)1) Anatomy and PhysiologyAnatomy and Physiology

2)2) TechniquesTechniques


A Neuraxial technique that offers a wider range of A Neuraxial technique that offers a wider range of applications than a Spinal Anestheticapplications than a Spinal Anesthetic

An Epidural block can be performed at the An Epidural block can be performed at the Lumbar, Thoracic, Cervical and Caudal levelLumbar, Thoracic, Cervical and Caudal level

Wide use of applications; Operative anesthesia, Wide use of applications; Operative anesthesia, Obstetric Anesthesia & Analgesia, Postop pain Obstetric Anesthesia & Analgesia, Postop pain control and Chronic Pain Managementcontrol and Chronic Pain Management

It can be used as a “Single Shot” or with a It can be used as a “Single Shot” or with a catheter that allows intermittent boluses or a catheter that allows intermittent boluses or a Continuous InfusionContinuous Infusion


One advantage of an Epidural is that the One advantage of an Epidural is that the muscle blockade can range from none to muscle blockade can range from none to completecomplete

Everything can be regulated and Everything can be regulated and changed by:changed by:

1)1) Choice of drugChoice of drug2)2) Concentration of LAConcentration of LA3)3) DosageDosage4)4) Level of InjectionLevel of Injection

AnatomyAnatomy

The Epidural space surrounds the Dura The Epidural space surrounds the Dura Mater posterior, laterally and anteriorlyMater posterior, laterally and anteriorly

Nerve roots travel in this space as they Nerve roots travel in this space as they exit the spinal cord laterallyexit the spinal cord laterally

They then exit the foramen and travel They then exit the foramen and travel peripherally to become peripheral nerves peripherally to become peripheral nerves carrying both afferent and efferent carrying both afferent and efferent pathwayspathways

AnatomyAnatomy

Other contents of the Epidural space Other contents of the Epidural space include:include:

1)1) Fatty connective tissueFatty connective tissue

2)2) LymphaticsLymphatics

3)3) Venous plexus (Batson’s)Venous plexus (Batson’s)

4)4) Septa and Connective tissue bandsSepta and Connective tissue bands

PhysiologyPhysiology

Local anesthetics or other solutions Local anesthetics or other solutions injected into the epidural space (steroids, injected into the epidural space (steroids, narcotics) spread anatomicallynarcotics) spread anatomically

Horizontal spread is to the region of the Horizontal spread is to the region of the dural cuffs with diffusion into the CSF and dural cuffs with diffusion into the CSF and leakage through the intervertebral foramen leakage through the intervertebral foramen into paravertebral spacesinto paravertebral spaces

Longitudinal spread is preferentially Longitudinal spread is preferentially cephalad in directioncephalad in direction


Possible sites of anesthetic action Possible sites of anesthetic action include:include:

1)1) Paravertebral nerve rootsParavertebral nerve roots2)2) Intradural spinal rootsIntradural spinal roots3)3) Dorsal and Ventral spinal rootsDorsal and Ventral spinal roots4)4) Dorsal root gangliaDorsal root ganglia5)5) The Spinal CordThe Spinal Cord6)6) The Brain itself (by diffusion)The Brain itself (by diffusion)


Initial blockade is PROBABLY a result of Initial blockade is PROBABLY a result of anesthetic blockade at the spinal roots within the anesthetic blockade at the spinal roots within the dural sleevesdural sleeves

The Dural Cuffs or Sleeves have a proliferation of The Dural Cuffs or Sleeves have a proliferation of arachnoid villi and granulations that effectively arachnoid villi and granulations that effectively reduce the THICKNESS of the dura mater reduce the THICKNESS of the dura mater facilitating rapid diffusion of the LA from the facilitating rapid diffusion of the LA from the Epidural space, through the Dura and into the Epidural space, through the Dura and into the CSF surrounding the nerve rootsCSF surrounding the nerve roots

Then the local anesthetic diffuses into the nerve Then the local anesthetic diffuses into the nerve root itself, producing anesthesia to that particular root itself, producing anesthesia to that particular dermatomedermatome


Because Epidural anesthesia is Because Epidural anesthesia is DIFFUSION dependent, relatively LARGE DIFFUSION dependent, relatively LARGE volumes of LA are needed to achieve a volumes of LA are needed to achieve a block that spans several dermatomesblock that spans several dermatomes

The block ONLY goes as high or low as The block ONLY goes as high or low as you regulate it (by volume)you regulate it (by volume)

It’s not like a Spinal which is It’s not like a Spinal which is EVERYTHING distal to the level of the EVERYTHING distal to the level of the block; it is a DIFFERENTIAL block block; it is a DIFFERENTIAL block dependent on the volume and site of dependent on the volume and site of injectioninjection

AdvantagesAdvantages

Consequently, Epidural techniques have the Consequently, Epidural techniques have the advantage of better control of level (and also of advantage of better control of level (and also of sympathetic blockade)sympathetic blockade)

Epidural techniques allow for the placement of a Epidural techniques allow for the placement of a continuous catheter which is especially useful continuous catheter which is especially useful for:for:

1)1) Cases of unpredictable durationCases of unpredictable duration2)2) Prolonged postoperative analgesiaProlonged postoperative analgesia3)3) Chronic pain controlChronic pain control4)4) Obstetric Analgesia & AnesthesiaObstetric Analgesia & Anesthesia

Spread of AnesthesiaSpread of Anesthesia

To be able to choose the most appropriate anesthetic To be able to choose the most appropriate anesthetic dose, concentration and volume of LA, the anesthetist dose, concentration and volume of LA, the anesthetist must be familiar with the variables that affect spread must be familiar with the variables that affect spread and duration of Epidural Anesthesiaand duration of Epidural Anesthesia

The variables are more numerous than those of spinal The variables are more numerous than those of spinal anesthesia and Baricity plays a VERY small factor anesthesia and Baricity plays a VERY small factor when dealing with Epidurals, whereas in a Spinal, when dealing with Epidurals, whereas in a Spinal, baricity is a KEY factor in spread and distribution of baricity is a KEY factor in spread and distribution of the blockthe block

Spread of AnesthesiaSpread of Anesthesia

The factors that affect the level of the Epidural block are:The factors that affect the level of the Epidural block are:1)1) Injection SiteInjection Site2)2) DoseDose3)3) VolumeVolume4)4) ConcentrationConcentration5)5) PositionPosition6)6) AgeAge7)7) Height and Weight (?)Height and Weight (?)• Pregnancy (?)Pregnancy (?)1)1) Speed of injection (?)Speed of injection (?)

Injection SiteInjection Site

INJECTION SITE:INJECTION SITE:Unlike Spinal anesthesia, Epidural anesthesia Unlike Spinal anesthesia, Epidural anesthesia produces a segmental block that spreads both produces a segmental block that spreads both caudally and craniallycaudally and craniallyBased on that fact, then the INJECTION SITE is Based on that fact, then the INJECTION SITE is arguably THE most important determinant of the arguably THE most important determinant of the spread of an epidural blockspread of an epidural blockThe injection site should be in the MIDDLE of the The injection site should be in the MIDDLE of the range of dermatomes that needs to be range of dermatomes that needs to be anesthetized and closest to the main nerve roots anesthetized and closest to the main nerve roots involvedinvolved


Caudal epidural blocks are largely Caudal epidural blocks are largely restricted to sacral and LOW lumbar restricted to sacral and LOW lumbar dermatomesdermatomes

Thoracic levels can be reached by the Thoracic levels can be reached by the caudal approach only if large volumes caudal approach only if large volumes (30cc) are given, and then the block is (30cc) are given, and then the block is patchy at best because of the distance that patchy at best because of the distance that the anesthetic has to travelthe anesthetic has to travel


Lumbar local anesthetic injections of 10cc Lumbar local anesthetic injections of 10cc tend to spread caudad to include all the tend to spread caudad to include all the sacral dermatomessacral dermatomes

Lumbar injections of 20cc volumes Lumbar injections of 20cc volumes produce much better quality sacral blocks produce much better quality sacral blocks and can also extend cranially to include the and can also extend cranially to include the midthoracic levelsmidthoracic levels


Thoracic injections tend to produce a symmetric Thoracic injections tend to produce a symmetric segmental band of anesthesia with minimal segmental band of anesthesia with minimal lumbar spreadlumbar spread

When using a thoracic approach, it is prudent to When using a thoracic approach, it is prudent to decrease your volume by about 30-50% to decrease your volume by about 30-50% to prevent cranially spreadprevent cranially spread

It is generally not feasible to produce surgical It is generally not feasible to produce surgical anesthesia in the low lumbar or sacral nerve anesthesia in the low lumbar or sacral nerve distributions when using thoracic injection sitesdistributions when using thoracic injection sites

Thoracic injection sites are ideally suited for Thoracic injection sites are ideally suited for procedures of the chest and upper abdomen or procedures of the chest and upper abdomen or for relief of post-op thoracotomy pain with a for relief of post-op thoracotomy pain with a catheter being placed for continuous infusionscatheter being placed for continuous infusions

Dose, Volume & ConcentrationDose, Volume & Concentration

Within the range typically used for surgical Within the range typically used for surgical anesthesia, drug CONCENTRATION is anesthesia, drug CONCENTRATION is relatively unimportant in determining relatively unimportant in determining block block spreadspread

DOSE & VOLUME, however, are important DOSE & VOLUME, however, are important variables in determining both spread and variables in determining both spread and quality of the Epidural block obtainedquality of the Epidural block obtained

Dose, Volume & ConcentrationDose, Volume & ConcentrationIf drug CONCENTRATION is held constant, If drug CONCENTRATION is held constant,

increasing the volume of LA (and thereby increasing the volume of LA (and thereby increasing the DOSE) results in significantly increasing the DOSE) results in significantly greater average spreadgreater average spread

DOSE = Volume x Concentration (i.e. 15cc x DOSE = Volume x Concentration (i.e. 15cc x 2.5mg/cc = 37.5mg; 20cc x 2.5mg/cc = 50mg)2.5mg/cc = 37.5mg; 20cc x 2.5mg/cc = 50mg)

The CONCENTRATION of the LA generally The CONCENTRATION of the LA generally affects the DENSITY of the block, NOT the affects the DENSITY of the block, NOT the spreadspread


So a small volume of a more concentrated So a small volume of a more concentrated LA will produce a very limited BUT very LA will produce a very limited BUT very strong blockstrong block

But take the same DOSE and double the But take the same DOSE and double the volume, the spread will increase BUT the volume, the spread will increase BUT the strength of the block may not be as intensestrength of the block may not be as intense


NOTE: The increase in block level IS NOT in NOTE: The increase in block level IS NOT in direct proportion to the volume increase. direct proportion to the volume increase. Doubling the volume WILL NOT double the block Doubling the volume WILL NOT double the block spread. It is a NON-linear relationship and spread. It is a NON-linear relationship and doubling the volume will only increase the level doubling the volume will only increase the level about 1/3-1/2 the original number of segmentsabout 1/3-1/2 the original number of segments

The same relationship exists with DOSE; The same relationship exists with DOSE; doubling the dose will usually only increase the doubling the dose will usually only increase the level of block the same 1/3-1/2 of the original level of block the same 1/3-1/2 of the original number of segments blockednumber of segments blocked


Recommended amounts of LA differ as to Recommended amounts of LA differ as to which level is being injected:which level is being injected:

Cervical/Thoracic doses are 0.7 to 1cc per Cervical/Thoracic doses are 0.7 to 1cc per segment with an initial volume of 10ccsegment with an initial volume of 10cc

Lumbar level doses are 1.25 – 1.5cc per Lumbar level doses are 1.25 – 1.5cc per segment with an initial volume of 15-20ccsegment with an initial volume of 15-20cc

This is due to the narrowing of the spinal This is due to the narrowing of the spinal canal as it progresses craniallycanal as it progresses cranially

Concentration and Differential BlockConcentration and Differential Block

Using a lower concentration anesthetic Using a lower concentration anesthetic can sometimes give you a differential blockcan sometimes give you a differential block

The lower concentration means the dose The lower concentration means the dose is lower and there is less LA to penetrate is lower and there is less LA to penetrate the nerve roots so the block acts more the nerve roots so the block acts more peripherally on the nerves, differentially peripherally on the nerves, differentially blocking sensory and pain fibers over blocking sensory and pain fibers over larger muscle fibers in the center of the larger muscle fibers in the center of the nervesnerves

Concentration and Differential BlockConcentration and Differential Block

An example of this is used in Obstetrics:An example of this is used in Obstetrics:Bupivicaine 0.25%, 20cc, usually ONLY provides a Bupivicaine 0.25%, 20cc, usually ONLY provides a sensory block but leaves the motor fibers intact so sensory block but leaves the motor fibers intact so the patient can push when needed tothe patient can push when needed to

If Bupivicaine 0.5% is given with the same volume, If Bupivicaine 0.5% is given with the same volume, then a sensory as well as motor block is obtained, then a sensory as well as motor block is obtained, paralyzing the muscles at the levels of the block so paralyzing the muscles at the levels of the block so NO pushing is going to be possibleNO pushing is going to be possible

There is quite a bit of individual sensitivity and There is quite a bit of individual sensitivity and some people may end up with a purely sensory some people may end up with a purely sensory block while others may end up with significant block while others may end up with significant muscle weakness or paralysis; (ooooppps!!)muscle weakness or paralysis; (ooooppps!!)

PositionPosition

Some people feel that the Lateral position Some people feel that the Lateral position is the preferred position to optimize spread is the preferred position to optimize spread

Others feel that the sitting position is Others feel that the sitting position is preferred due to anatomical advantagespreferred due to anatomical advantages

Studies have shown small to NO Studies have shown small to NO differences in spread of block when differences in spread of block when comparing the two positions; it’s your comparing the two positions; it’s your preference which one to usepreference which one to use

AgeAge

Most (but NOT all) studies that have Most (but NOT all) studies that have examined the effect of age on Epidural examined the effect of age on Epidural blocks have demonstrated a greater blocks have demonstrated a greater spread in older patientsspread in older patients

This is thought to be related to a less This is thought to be related to a less compliant epidural space and Dura Matercompliant epidural space and Dura Mater

Even so, the clinical effect is usually AT Even so, the clinical effect is usually AT MOST an increase of no more than three MOST an increase of no more than three or four dermatomesor four dermatomes

Height and WeightHeight and Weight

The correlation between patient Height or The correlation between patient Height or Weight and spread of epidural block is very Weight and spread of epidural block is very weak at best and seems to have no clinical weak at best and seems to have no clinical significancesignificance

The only instance where it may have an The only instance where it may have an effect is in EXTREMELY TALL people effect is in EXTREMELY TALL people (greater than 6’6”) or in EXTREMELY (greater than 6’6”) or in EXTREMELY SHORT (less than 4’10”) or in MORBIDLY SHORT (less than 4’10”) or in MORBIDLY obese patientsobese patients

PregnancyPregnancy

Studies examining the effect of pregnancy Studies examining the effect of pregnancy on spread of Epidural blocks are conflictingon spread of Epidural blocks are conflicting

Some have shown a greater spread at Some have shown a greater spread at TERM and early in pregnancyTERM and early in pregnancy

Other studies have shown no significant Other studies have shown no significant differences in level of spread between differences in level of spread between pregnant and non-pregnant patientspregnant and non-pregnant patients

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Speed of InjectionSpeed of Injection

Some feel that a rapid injection will increase the Some feel that a rapid injection will increase the level of spread or decrease the time it takes for level of spread or decrease the time it takes for the block to setthe block to set

This has NEVER been shown to make any This has NEVER been shown to make any difference in eitherdifference in either

Drugs should, in fact, be injected SLOWLY to Drugs should, in fact, be injected SLOWLY to avoid rapid increases in CSF pressure, headache avoid rapid increases in CSF pressure, headache and increased intracranial pressuresand increased intracranial pressures

Also, incremental bolus vs. slow, steady injection Also, incremental bolus vs. slow, steady injection has shown NO difference in level of spread in has shown NO difference in level of spread in multiple studiesmultiple studies


All solutions should be injected in All solutions should be injected in increments of 3-5cc every 3 minutes and increments of 3-5cc every 3 minutes and titrated to the desired anesthetic leveltitrated to the desired anesthetic level

If a catheter has been placed and you are If a catheter has been placed and you are injecting through the catheter, then the injecting through the catheter, then the catheter needs to be aspirated prior to catheter needs to be aspirated prior to every injection to show no CSF is presentevery injection to show no CSF is present


This gradual administration of medication slows This gradual administration of medication slows the rate of onset of the anesthetic level and the rate of onset of the anesthetic level and controls the development of the sympathetic controls the development of the sympathetic blockadeblockade

This is an advantage that you have with an This is an advantage that you have with an Epidural that you DO NOT have with a SpinalEpidural that you DO NOT have with a Spinal

The Spinal is ALL or none, whereas the Epidural The Spinal is ALL or none, whereas the Epidural can be brought up gradually, slowing whatever can be brought up gradually, slowing whatever hypotensive response you may have to a more hypotensive response you may have to a more manageable level (and saving you an extra pair of manageable level (and saving you an extra pair of pants!!)pants!!)

Onset of BlockadeOnset of Blockade

The onset of an epidural block can usually be The onset of an epidural block can usually be detected within 5 minutes in the dermatomes detected within 5 minutes in the dermatomes immediately surrounding the injection siteimmediately surrounding the injection site

The time to PEAK effect differs somewhat among The time to PEAK effect differs somewhat among different LA’sdifferent LA’s

Shorter acting drugs usually reach their maximum Shorter acting drugs usually reach their maximum spread in 15-20 minutesspread in 15-20 minutes

Longer acting LA’s usually reach their maximum Longer acting LA’s usually reach their maximum spread in 20-25 minutesspread in 20-25 minutes

Increasing the DOSE of LA SPEEDS the onset of Increasing the DOSE of LA SPEEDS the onset of both motor and sensory blockboth motor and sensory block

Duration of BlockDuration of Block

The DURATION of the Epidural block The DURATION of the Epidural block depends on:depends on:

1)1) The LA itselfThe LA itself

2)2) Dose givenDose given

3)3) Patient agePatient age

4)4) Use of Adrenergic AgonistsUse of Adrenergic Agonists

Local Anesthetics & DurationLocal Anesthetics & Duration

Your choice of LA is the most important Your choice of LA is the most important factor in determining DURATION of the factor in determining DURATION of the blockblock

Chlorprocaine is shortest, Lidocaine & Chlorprocaine is shortest, Lidocaine & Mepivicaine are intermediate and Mepivicaine are intermediate and Bupivicaine and Ropivicaine produce the Bupivicaine and Ropivicaine produce the longest lasting Epidural blockslongest lasting Epidural blocks

LA’s & DurationLA’s & Duration

Back to the differential block topic:Back to the differential block topic:

ETIDOCAINE is a long acting agent that has ETIDOCAINE is a long acting agent that has a profound muscle relaxation effect but a a profound muscle relaxation effect but a weak sensory effect, so you would end up weak sensory effect, so you would end up with a paralyzed patient in severe pain; it with a paralyzed patient in severe pain; it has been almost completely eliminated from has been almost completely eliminated from use as a result of this differential blockadeuse as a result of this differential blockade

LA’s and DurationLA’s and Duration

On the flip side, BUPIVICAINE is the On the flip side, BUPIVICAINE is the opposite of Etidocaineopposite of Etidocaine

In lower doses (concentrations) In lower doses (concentrations) BUPIVICAINE seems to have a preferential BUPIVICAINE seems to have a preferential sensory block with minimal motor effectsensory block with minimal motor effect

That is why it is an ideal drug for Obstetric That is why it is an ideal drug for Obstetric ANALGESIA during labor, eliminating pain ANALGESIA during labor, eliminating pain while preserving muscle functionwhile preserving muscle function

Dose and AgeDose and Age

DOSE: Increasing the DOSE of a LA DOSE: Increasing the DOSE of a LA results in increased duration AND density results in increased duration AND density of the blockof the block

AGE: There are conflicting studies, but the AGE: There are conflicting studies, but the majority seem to show a longer duration of majority seem to show a longer duration of action in the elderly population. The exact action in the elderly population. The exact reason is unknown and more studies need reason is unknown and more studies need to be performed to be performed

Adrenergic Agents and DurationAdrenergic Agents and Duration

Epinephrine in a concentration of 5 Epinephrine in a concentration of 5 micrograms/cc (1:200,000) is the most common micrograms/cc (1:200,000) is the most common adrenergic agent added to epidural LA’sadrenergic agent added to epidural LA’s

It has been shown to prolong the blocks of It has been shown to prolong the blocks of Lidocaine and Mepivicaine by as much as 80%Lidocaine and Mepivicaine by as much as 80%

Epinephrine has been shown NOT to significantly Epinephrine has been shown NOT to significantly prolong the duration of anesthesia when added to prolong the duration of anesthesia when added to concentrated solutions of Bupivicaine and concentrated solutions of Bupivicaine and Ropivicaine used for surgical anesthesiaRopivicaine used for surgical anesthesia

Adrenergic Agents and DurationAdrenergic Agents and Duration

However, when added to more dilute However, when added to more dilute concentrations of Bupivicaine, as used for OB concentrations of Bupivicaine, as used for OB Analgesia, it has been shown to increase the Analgesia, it has been shown to increase the duration AND quality of the blockduration AND quality of the block

The mechanism proposed, although never The mechanism proposed, although never proven, is that through vasoconstriction, it slows proven, is that through vasoconstriction, it slows the systemic absorption and elimination of the LAthe systemic absorption and elimination of the LA

Why it does not work with higher concentrations Why it does not work with higher concentrations of Bupivicaine and Ropivicaine is not clearly of Bupivicaine and Ropivicaine is not clearly understoodunderstood

A & P ConclusionA & P Conclusion

The extent and duration of both Spinal The extent and duration of both Spinal AND Epidural blocks are influenced by a AND Epidural blocks are influenced by a number of variables, some of which are number of variables, some of which are under the control of the anesthetistunder the control of the anesthetist

Understanding the impact of these Understanding the impact of these variables will allow the anesthetist to select variables will allow the anesthetist to select the most appropriate drug and dose for the most appropriate drug and dose for any given clinical situationany given clinical situation


HOWEVER, even the most experienced HOWEVER, even the most experienced anesthetist will STILL have blocks that are anesthetist will STILL have blocks that are not adequate or may fail completelynot adequate or may fail completely

The frequency of failed blocks can be kept The frequency of failed blocks can be kept to a minimum if the clinician aims for a to a minimum if the clinician aims for a block that is a little higher and a little longer block that is a little higher and a little longer than would ideally be used for the given than would ideally be used for the given procedureprocedure


REMEMBER, it is often easier to deal with REMEMBER, it is often easier to deal with a block that is too high or too long than to a block that is too high or too long than to attempt to cover up for a block that is too attempt to cover up for a block that is too low or not dense enoughlow or not dense enough

It’s always better to have a little more than It’s always better to have a little more than a little less, especially with Regional a little less, especially with Regional AnesthesiaAnesthesia

Break Time!!Break Time!!

TechniqueTechnique

Patient preparation and positioning are Patient preparation and positioning are similar to a Spinal Anestheticsimilar to a Spinal Anesthetic

Either the sitting or lateral decubitus Either the sitting or lateral decubitus positions can be usedpositions can be used

Emergency equipment and monitors Emergency equipment and monitors should be immediately available and you should be immediately available and you need to be prepared to use it if any thing need to be prepared to use it if any thing goes wronggoes wrong

TechniqueTechnique

The most commonly performed Epidural is The most commonly performed Epidural is a Lumbar Epidural, followed by a Caudal, a Lumbar Epidural, followed by a Caudal, then Thoracic and finally Cervicalthen Thoracic and finally Cervical

Today most high thoracic and cervical Today most high thoracic and cervical epidurals are performed under flouroscopic epidurals are performed under flouroscopic guidance by pain specialists as it takes a guidance by pain specialists as it takes a greater level of skill to successfully perform greater level of skill to successfully perform those proceduresthose procedures

TechniqueTechnique

As you can see in the following diagram, As you can see in the following diagram, the angles of approach for the various the angles of approach for the various levels are markedly differentlevels are markedly different

The Lumbar region is at or greater than 90 The Lumbar region is at or greater than 90 degrees to the skindegrees to the skin

The Thoracic is at a much more acute The Thoracic is at a much more acute angle due to the anatomical arrangement angle due to the anatomical arrangement of the Thoracic Spinous Processesof the Thoracic Spinous Processes

Finally the Cervical is at an angle in Finally the Cervical is at an angle in between the previous twobetween the previous two

TechniqueTechnique

The Lumbar region is by far the easiest due to:The Lumbar region is by far the easiest due to:

1)1) The angle of the Spinous processesThe angle of the Spinous processes

2)2) The larger spaces BETWEEN adjacent spinous The larger spaces BETWEEN adjacent spinous processesprocesses

3)3) Easily identifiable location by using easy to find Easily identifiable location by using easy to find landmarks (Iliac crests)landmarks (Iliac crests)

4)4) Width of epidural space is greatest at this level Width of epidural space is greatest at this level as well so if you are a little off the mark, you still as well so if you are a little off the mark, you still stand a good chance of finding itstand a good chance of finding it

TechniqueTechnique

With a Spinal Anesthetic, the practitioner With a Spinal Anesthetic, the practitioner seeks CSF by piercing the Duraseeks CSF by piercing the Dura

In an Epidural, the practitioner seeks to In an Epidural, the practitioner seeks to place the tip of the needle into the fat-filled place the tip of the needle into the fat-filled space DEEP to the Ligamentum Flavum space DEEP to the Ligamentum Flavum and SHALLOW to the Duraand SHALLOW to the Dura

This is done by using a completely This is done by using a completely different needle and injection technique different needle and injection technique than with a Spinal anestheticthan with a Spinal anesthetic

TechniqueTechnique

The Epidural is most often performed with a 16, The Epidural is most often performed with a 16, 17 or 18 gauge needle with a BLUNTED tip 17 or 18 gauge needle with a BLUNTED tip designed to facilitate passage of a catheter into designed to facilitate passage of a catheter into the epidural space at the beginning or end of the the epidural space at the beginning or end of the procedureprocedure

The blunted tip is also designed specially to The blunted tip is also designed specially to AVOID puncture of the dura and if it comes in AVOID puncture of the dura and if it comes in contact with the Dura, the lack of a sharp point will contact with the Dura, the lack of a sharp point will hopefully just inwardly push the dura without hopefully just inwardly push the dura without puncturing itpuncturing it

TechniqueTechnique

The procedure is begun by identifying your The procedure is begun by identifying your anatomical landmarks and locating your planned anatomical landmarks and locating your planned interspace of insertioninterspace of insertion

Then the patient is positioned similar to that of a Then the patient is positioned similar to that of a Spinal AnestheticSpinal Anesthetic

A sterile prep is performed with the planned A sterile prep is performed with the planned insertion point at the center of both the prepped insertion point at the center of both the prepped area and in the middle of the special hole in the area and in the middle of the special hole in the drape that is provided in the kitdrape that is provided in the kit

TechniqueTechnique

Local anesthetic (usually Lido 1% plain) is Local anesthetic (usually Lido 1% plain) is injected at the planned insertion site and a skin injected at the planned insertion site and a skin wheal is raised with an injection of 1-2 cc of local wheal is raised with an injection of 1-2 cc of local with the 25g skin needle (see kit)with the 25g skin needle (see kit)

Then some people change local needles and Then some people change local needles and place the 22g needle on the local syringe, and in place the 22g needle on the local syringe, and in the center of the skin wheal, go deeper along the the center of the skin wheal, go deeper along the planned injection tract, injecting slowly as they planned injection tract, injecting slowly as they penetrate deeper into the subcutaneous tissuepenetrate deeper into the subcutaneous tissue

Needle StabilizationNeedle Stabilization

Firmly place the BACK of your non-dominant Firmly place the BACK of your non-dominant hand against the patient’s skin and below the hand against the patient’s skin and below the epidural needleepidural needle

Then grasp the needle and eventually the hub Then grasp the needle and eventually the hub once the epidural space is found between your once the epidural space is found between your thumb and index finger of your non-dominant thumb and index finger of your non-dominant hand as it stays in contact with the patient’s back hand as it stays in contact with the patient’s back (the Bromage Grip)(the Bromage Grip)

This stabilizes the needle and prevents any This stabilizes the needle and prevents any unwanted movement either in or out which is unwanted movement either in or out which is especially critical once you find the Epidural especially critical once you find the Epidural space space

TechniqueTechnique

The Epidural needle is place bevel up and The Epidural needle is place bevel up and introduced into the skinintroduced into the skin

It is passed slowly through the Supraspinous It is passed slowly through the Supraspinous ligament and seated in the Interspinous Ligament ligament and seated in the Interspinous Ligament before the stylet is removedbefore the stylet is removed

You can tell that the needle is seated in the You can tell that the needle is seated in the Interspinous ligament by letting go of the needle; Interspinous ligament by letting go of the needle; it should still be supported in the same position, it should still be supported in the same position, not drop down not drop down

TechniqueTechnique

After the stylet is removed, the needle is slowly After the stylet is removed, the needle is slowly advanced using the “Loss of Resistance” advanced using the “Loss of Resistance” techniquetechnique

The LOR syringe is typically made of glass and is The LOR syringe is typically made of glass and is filled with either 3-4cc of air, normal saline, or a filled with either 3-4cc of air, normal saline, or a mixture of saline and airmixture of saline and air

As the syringe/needle combo is advanced, As the syringe/needle combo is advanced, pressure is applied to the plunger of the syringe pressure is applied to the plunger of the syringe by “Bouncing” or intermittently applying pressure by “Bouncing” or intermittently applying pressure to the plungerto the plunger

The pattern is “move-bounce-move-bounce-The pattern is “move-bounce-move-bounce-move-bounce” until LOR is obtained move-bounce” until LOR is obtained

TechniqueTechnique

The syringe/needle combo should only be moved The syringe/needle combo should only be moved 0.5-1cm at a time and then tested for resistance 0.5-1cm at a time and then tested for resistance or LORor LOR

The syringe/needle combo is advanced by The syringe/needle combo is advanced by applying pressure to the NEEDLE and not the applying pressure to the NEEDLE and not the syringesyringe

As the needle passes through the Ligamentum As the needle passes through the Ligamentum Flavum, resistance increases and you may feel a Flavum, resistance increases and you may feel a distinct “pop” as you pass through itdistinct “pop” as you pass through it

Once you pass through the LF, you will Once you pass through the LF, you will experience an immediate LOR and then the tip of experience an immediate LOR and then the tip of the needle will be in the Epidural Spacethe needle will be in the Epidural Space

TechniqueTechnique

In younger patients like you may In younger patients like you may encounter in Obstetrics, there may not be encounter in Obstetrics, there may not be a distinct “pop” of the LF, just a sudden a distinct “pop” of the LF, just a sudden loss of resistanceloss of resistance

Once the Epidural space is reached, pass Once the Epidural space is reached, pass your stylet through the needle to make your stylet through the needle to make sure there are no tissue plugs possibly sure there are no tissue plugs possibly blocking the flow of CSF with an blocking the flow of CSF with an inadvertent Dural punctureinadvertent Dural puncture

TechniqueTechnique

Once it is determined that your needle tip Once it is determined that your needle tip is in the Epidural space, begin first by is in the Epidural space, begin first by injecting a “TEST” dose of 3cc of LA injecting a “TEST” dose of 3cc of LA containing Epi (Lido 1.5% w/Epi)containing Epi (Lido 1.5% w/Epi)

If you are intravascular, you will see an If you are intravascular, you will see an increase in heart rate within 30 secondsincrease in heart rate within 30 seconds

It is also important to question the patient It is also important to question the patient after the injection of your test doseafter the injection of your test dose

TechniqueTechnique

The questions asked should be aimed at The questions asked should be aimed at determining if you may have inadvertently determining if you may have inadvertently obtained a dural puncture or are possible obtained a dural puncture or are possible injecting directly into the vascular systeminjecting directly into the vascular system

Besides the tachycardia, with an Besides the tachycardia, with an Intravascular injection, the patient may Intravascular injection, the patient may experience a “ringing” or “buzzing” in the experience a “ringing” or “buzzing” in the ears, a metallic taste in the mouth or ears, a metallic taste in the mouth or circumoral numbnesscircumoral numbness

TechniqueTechnique

If you happen to have gotten a dural If you happen to have gotten a dural puncture by accident, the test dose should puncture by accident, the test dose should produce numbness and/or weakness or a produce numbness and/or weakness or a “pins and needles” sensation in the lower “pins and needles” sensation in the lower extremitiesextremities

This can take up to three minutes to occur, This can take up to three minutes to occur, so you need to wait at least three minutes so you need to wait at least three minutes before continuing your injection of LAbefore continuing your injection of LA

TechniqueTechnique

At this point, techniques and opinions At this point, techniques and opinions differ as to whether to pass a catheter and differ as to whether to pass a catheter and inject your total dose via the catheter or inject your total dose via the catheter or inject your total dose through the needle inject your total dose through the needle and then insert the catheterand then insert the catheter

The catheter first crowd feels that it is The catheter first crowd feels that it is better because you can slowly raise your better because you can slowly raise your level of anesthesia having better control level of anesthesia having better control and less incidence of sympathetic blockand less incidence of sympathetic block

TechniqueTechnique

The problem with the cath first is that it is The problem with the cath first is that it is possible for the catheter NOT to go possible for the catheter NOT to go correctly into the epidural space. It may correctly into the epidural space. It may come out a nerve root or kink or coil up come out a nerve root or kink or coil up and then you will be performing a useless and then you will be performing a useless epidural which will end up not working or epidural which will end up not working or be patchy or one sidedbe patchy or one sided

TechniqueTechnique

The needle crowd believe that the injection The needle crowd believe that the injection of the LA opens up and distends the of the LA opens up and distends the epidural space and makes it easier to pass epidural space and makes it easier to pass the catheter into the correct locationthe catheter into the correct location

Also, if the catheter fails, you will have a Also, if the catheter fails, you will have a complete block for a period of time and complete block for a period of time and that may be all the time you need to that may be all the time you need to complete the surgery or procedurecomplete the surgery or procedure

TechniqueTechnique

Regardless of which technique is used, as Regardless of which technique is used, as you pass the catheter, the patient should you pass the catheter, the patient should be warned that at that moment they may be warned that at that moment they may feel an “electric shock” or a feeling like feel an “electric shock” or a feeling like they hit their “funny bone”they hit their “funny bone”

This is caused by the cath tip brushing up This is caused by the cath tip brushing up against a nerve root or two as it is passed against a nerve root or two as it is passed into the epidural spaceinto the epidural space

TechniqueTechnique

As you pass the catheter, you may initially As you pass the catheter, you may initially feel resistance at the tip of the needlefeel resistance at the tip of the needle

A slightly stronger push may be needed A slightly stronger push may be needed and then you will feel the resistance drop and then you will feel the resistance drop and the catheter will thread smoothlyand the catheter will thread smoothly

It should be inserted between 3-5cm and It should be inserted between 3-5cm and no more (3-5 little black lines)no more (3-5 little black lines)

CAUTIONCAUTION

NEVERNEVER pull the catheter back pull the catheter back through the needle once it has been through the needle once it has been insertedinserted

It is possible to catch the catheter on the It is possible to catch the catheter on the needle tip and shear or cut the tip offneedle tip and shear or cut the tip off

Then it becomes a permanent new Then it becomes a permanent new addition to the epidural space and will be addition to the epidural space and will be there for the rest of the patient’s life!!!!there for the rest of the patient’s life!!!!

Caudal AnesthesiaCaudal Anesthesia

An Epidural technique used for anorectal An Epidural technique used for anorectal surgery in adultssurgery in adults

Also one of the most commonly done Also one of the most commonly done regional techniques in pediatric patientsregional techniques in pediatric patients

Technique is the same for both patient Technique is the same for both patient populationspopulations

Difference lies of course with size of Difference lies of course with size of equipment and dosage of anesthesiaequipment and dosage of anesthesia


Caudal anesthesia involves needle or Caudal anesthesia involves needle or catheter penetration of the Sacrococcygeal catheter penetration of the Sacrococcygeal Ligament covering the Sacral HiatusLigament covering the Sacral Hiatus

The Hiatus is created by the unfused S4 The Hiatus is created by the unfused S4 and S5 laminaand S5 lamina

The Hiatus can be felt as a groove or The Hiatus can be felt as a groove or notch above the coccyx and between two notch above the coccyx and between two bony prominences, the Sacral Cornuabony prominences, the Sacral Cornua


The Posterior Superior Iliac Spines and the Sacral The Posterior Superior Iliac Spines and the Sacral Hiatus form a triangle (see photo)Hiatus form a triangle (see photo)

The patient is placed either prone or in lateral The patient is placed either prone or in lateral decubitusdecubitus

A Sterile prep is done similar to an epidural and the A Sterile prep is done similar to an epidural and the landmarks are again palpatedlandmarks are again palpated

A needle or catheter is inserted at a 45 degree A needle or catheter is inserted at a 45 degree angle to the skin until a “pop” is feltangle to the skin until a “pop” is felt

Then the angle of the needle is dropped down and Then the angle of the needle is dropped down and advanced, aspirating for blood or CSF every 1-2cmadvanced, aspirating for blood or CSF every 1-2cm


Some clinicians recommend test dosing as Some clinicians recommend test dosing as with other techniques, while most simply with other techniques, while most simply rely on incremental dosing with frequent rely on incremental dosing with frequent aspirationsaspirations

Repeated injections can be given or a Repeated injections can be given or a catheter can be placed for boluses or a catheter can be placed for boluses or a continuous infusioncontinuous infusion


For adults undergoing anorectal procedures, For adults undergoing anorectal procedures, caudal anesthesia can provide dense sacral caudal anesthesia can provide dense sacral sensory blockade with limited cephalad spreadsensory blockade with limited cephalad spread

A dose of 15-20cc of 1.5-2.0% Lidocaine with or A dose of 15-20cc of 1.5-2.0% Lidocaine with or w/o epi is usually effectivew/o epi is usually effective

This technique should be avoided in patients with This technique should be avoided in patients with Pilonidal cysts because the needle may pass Pilonidal cysts because the needle may pass through the cyst track and introduce bacteria into through the cyst track and introduce bacteria into the epidural space and lead to infection and the epidural space and lead to infection and abscess formationabscess formation

Conversion for C-SectionConversion for C-Section

A clinical situation that you will be faced with is A clinical situation that you will be faced with is one in which the patient has an Epidural in place one in which the patient has an Epidural in place for labor and is receiving Bupivicaine 0.125 -for labor and is receiving Bupivicaine 0.125 -0.0625% infusion or periodic Bupivicaine 0.25% 0.0625% infusion or periodic Bupivicaine 0.25% boluses and now has to be converted to a more boluses and now has to be converted to a more intense level of anesthesia for a C-sectionintense level of anesthesia for a C-section

The normal Epidural dose of Lidocaine 2% w/epi The normal Epidural dose of Lidocaine 2% w/epi for a C-section is 15-18cc WITHOUT an epidural for a C-section is 15-18cc WITHOUT an epidural in placein place

Conversion for C-sectionConversion for C-section

How much do you give if a Labor epidural How much do you give if a Labor epidural is in place to avoid a high block with is in place to avoid a high block with respiratory compromise????? respiratory compromise?????

Opinions vary as much as there are Opinions vary as much as there are anesthetists!!!anesthetists!!!

Some say that with a GOOD labor Epidural Some say that with a GOOD labor Epidural in place, no more that 12cc should be in place, no more that 12cc should be given; others say no more than 10cc and given; others say no more than 10cc and some go as high as 15ccsome go as high as 15cc

Conversion for C-sectionConversion for C-section

This is a situation in which many factors This is a situation in which many factors come in to play:come in to play:

1)1) The quality of the existing blockThe quality of the existing block

2)2) Infusion or bolus and how long since the Infusion or bolus and how long since the last bolus?last bolus?

3)3) Has the infusion been turned off for any Has the infusion been turned off for any length of time prior to the C-section for length of time prior to the C-section for the patient to push?the patient to push?

Conversion for C-sectionConversion for C-sectionUnfortunately, depending on the answer to Unfortunately, depending on the answer to

those questions, your dose may vary from those questions, your dose may vary from a low of 10cc to a max normal dose of 15-a low of 10cc to a max normal dose of 15-18cc18cc

Only clinical experience can be called Only clinical experience can be called upon in this situation so until you feel upon in this situation so until you feel comfortable with your decision, always comfortable with your decision, always consult with your attending or another consult with your attending or another CRNA with greater clinical experience than CRNA with greater clinical experience than youyou

ConclusionConclusion

Spinal and Epidural anesthesia each have Spinal and Epidural anesthesia each have advantages and disadvantages that may make advantages and disadvantages that may make one or the other technique better suited to a one or the other technique better suited to a particular patient or procedureparticular patient or procedure

Studies comparing both techniques have Studies comparing both techniques have consistently found that Spinal anesthesia takes consistently found that Spinal anesthesia takes less time to perform, produces more rapid onset less time to perform, produces more rapid onset of both sensory and motor block and is associated of both sensory and motor block and is associated with less pain during surgerywith less pain during surgery


Despite these important advantages, Despite these important advantages, Epidural anesthesia offers advantages, tooEpidural anesthesia offers advantages, too

Chief among them are the lower risk of Chief among them are the lower risk of PDPH, less hypotension, the ability to PDPH, less hypotension, the ability to prolong or extend the block using an prolong or extend the block using an indwelling catheter, and options to use the indwelling catheter, and options to use the same catheter for postoperative analgesiasame catheter for postoperative analgesia


Despite the advantages and disadvantages of Despite the advantages and disadvantages of BOTH techniques and even done with very BOTH techniques and even done with very experienced hands, BOTH blocks can have experienced hands, BOTH blocks can have systemic, toxic reactions and complicationssystemic, toxic reactions and complications

Be vigilant, be cautious, and be prepared to Be vigilant, be cautious, and be prepared to handle all the emergencies and complications that handle all the emergencies and complications that can occur with BOTHcan occur with BOTH

Again, always be prepared to convert to GA at a Again, always be prepared to convert to GA at a moment’s notice and keep thinking “What if…..”moment’s notice and keep thinking “What if…..”

epidural anesthesia

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