Complications of Neuraxial Blockade - PowerPoint Presentation

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Complications of Neuraxial Blockade

Developing Countries Regional Anesthesia Lecture SeriesDaniel D. Moos CRNA, Ed.D. U.S.A. moosd@charter.net

Lecture 13

Soli

Deo

Gloria

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Disclaimer

Every effort was made to ensure that material and information contained in this presentation are correct and up-to-date. The author can not accept liability/responsibility from errors that may occur from the use of this information. It is up to each clinician to ensure that they provide safe anesthetic care to their patients.

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Introduction

Exaggerated physiological responseAssociated with needle placementAssociated with catheter placementAssociated with medication toxicity

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Medical Liability- In General

Administration of regional anesthesia constitutes 18% of all claims in the US64% are temporary and non disabling13% involve death10% permanent nerve injury8% brain damage4% are “other”

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Medical Liability- Neuraxial Blockade

76% of all claims were related to neuraxial blockadeEpidural’s comprised 42%Spinal’s comprised 34%Caudal comprised 2%The population most affected is the obstetric population

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Adverse or Exaggerated Physiological Response Include:

High neural blockadeCardiac arrestUrinary retention

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Adverse or Exaggerated Physiological Response

This category is an extension of “normal” physiologic manifestations.The main point is vigilance and early treatment. Treat hypotension early and do not let it progress to cardiac arrest.Knowledge, preparation, and anticipation can help reduce adverse or exaggerated physiological responses

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High Neural Blockade

Can occur with either spinal or epidural techniques

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High Neural Blockade Causes

Excessive doses of local anesthetic are administeredFailure to reduce dose in patients susceptible to excessive spread (i.e. the elderly, pregnant, obese, or short patients)Unusual sensitivityUnusual excessive spread

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High Neural Blockade

Constant monitoring of the patients vital signs and block level are imperative Use of alcohol wipes (to assess cold sensation) and/or pinprick test will helpIncremental dosing is important with an epiduralWith hyperbaric techniques you can change the patients position to slow down the cephalad spread (i.e. reverse Trendelenberg)

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High Neural Blockade-Prevention

Careful consideration in dosing your blockAnticipation of potential complicationsPlan of action if complications occurContinual monitoring of the patient as the block progresses

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High Neural Blockade- Initial Symptoms

DyspneaNumbness and tingling of the upper extremities (i.e. fingers)Nausea generally precedes hypotension due to hypoperfusion of the chemoreceptor trigger zoneMild to moderate hypotension

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High Neural Blockade- Initial Treatment

Change position with hyperbaric techniqueStop the administration of local anesthetics with an epidural techniqueSupplemental oxygenOpen up the IV fluidsTreat hypotension with ephedrine or phenylephrineTreat bradycardia

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High Neural Blockade- Initial Treatment

Choose your vasopressor carefully.If patient is hypotensive and bradycardic then ephedrine would be indicatedEphedrine will increase heart rate as well as constrict blood vesselsPhenylephrine can result in reflex bradycardia as it constricts blood vesselsIf patient is hypotensive and tachycardic or normal in respect to heart rate then phenylephrine may be indicated

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High Neural Blockade- Initial Treatment

Refractory hypotension and/or hypotension should be treated rapidly with 5-10 mcg of epinephrine

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High Neural Blockade- Spread to Cervical Dermatomes Signs and Symptoms May Include:

Severe hypotensionBradycardiaRespiratory insufficiency including apneaUnconsciousness

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High Neural Blockade- Cervical Dermatomes Treatment

The A,B,C’sAirway and breathing- supplemental oxygen, maintain a patent airway, intubation, mechanical ventilationCirculation- aggressive intravenous fluid administration, ephedrine, phenylephrine, epinephrineBradycardia should be treated with atropineDopamine infusions may help

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High Neural Blockade- Cervical Dermatomes Treatment

Early and aggressive treatment may help avoid a cardiac arrest!Once patient has been stabilized and successfully treated the decision to proceed is based on individual circumstancesConsiderations include time spent hypotensive, indications of myocardial ischemia, etc.The respiratory compromise associated with high neural blockade are often transient

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Cardiac Arrest Due to Neuraxial Blockade

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Cardiac Arrest Due to Neuraxial Blockade

Cardiac arrest can occur with either epidural or spinal anesthesiaMore common with spinal anesthesia and the incidence may be as high as 1:1,500Usually preceded by bradycardiaCan easily occur in the young and healthy

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Cardiac Arrest Due to Neuraxial Blockade- Keys to Prevention

Appropriate hydration (i.e. 1 liter to an average sized adult)- must be administered within approximately 15 minutes since the majority of crystalloid solution will leave the intravascular spaceAggressively treat bradycardia, atropine, ephedrine, epinephrineDo not be fooled by the 26 year old marathon runner- patients with a slow heart rate and high vagal tone are at risk for cardiac arrest during spinal anesthesiaTotal sympathectomy with unopposed vagal stimulationError on the conservative and treat the patient

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Cardiac Arrest Due to Neuraxial Blockade- Risk Factors

Baseline heart rate < 60 bpmASA class IUse of Beta BlockersSensory level > T6Prolonged P-R interval

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Urinary Retention

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Urinary Retention

Due to blockade of S2-S4Leads to a decrease in bladder tone and inhibition of normal voiding reflexNeuraxial opioids may contribute to urinary retentionMore common in elderly men and those with a history of benign prostatic hypertrophy

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Urinary Retention

Urinary catheterizes should be provided for patients undergoing moderate to lengthy proceduresPostoperative assessment is important to detect urinary retentionProlonged urinary retention may be a sign of serious neurological injury

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Complications Associated with Needle Placement or Catheter Insertion

Inadequate anesthesia or analgesiaInadvertent intravascular injectionTotal spinalSubdural injectionBackachePostdural puncture headacheNeurological injury

Spinal or epidural hematomaMeningitis and arachnoiditisEpidural abscess

Sheering off the tip of the epidural catheter

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Inadequate Analgesia or Anesthesia

Rate of block failure is low but can be frustratingMust always be prepared to convert to general anesthesia or supplementRate of block failure decreases as experience increases

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Inadequate Analgesia or Anesthesia- May be associated with:

Outdated or improperly stored local anesthetics (tetracaine looses potency when stored for long periods in a warm environment)

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Inadequate Analgesia or Anesthesia- May be associated with:

Needle movement once free flowing CSF is noted- helpful to confirm aspiration before, during, and after injectionEven with free flowing CSF it is possible that the spinal needle is not entirely in the subarachnoid space resulting in a partial subdural injection and partial spinal

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Inadequate Analgesia or Anesthesia- May be associated with:

Epidural anesthesia is more subjective since you have to rely on confirmation by loss of resistance or hanging drop techniqueEither technique can lead to false positivesSpread of local anesthetic is less predictable

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Inadequate Analgesia or Anesthesia- May be associated with anatomical factors with epidural

Soft spinal ligament can occur in the very young and in obstetrics…this results in never achieving a good loss of resistanceIf you are off the midline slightly you may be in the paraspinous muscle and not in the spinal ligaments

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Inadequate Analgesia or Anesthesia- May be associated with anatomical factors with epidural

Block failure may occur if the epidural catheter migrates into the subdural spaceInjection of local anesthetics into this space may result in Horner’s syndrome, a high spinal, or an absence of any effect

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Inadequate Analgesia or Anesthesia

Local anesthetic toxicity can occur if the epidural catheter is placed into a vesselA high spinal can occur if the epidural catheter is placed in a subarachnoid space- stresses importance of the test dose

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Inadequate Analgesia or Anesthesia

Septations within the epidural space may create a barrier to the spread of local anesthetic and some segments may lack anesthesiaL5, S1, S2 are all large nerve roots and the large size may prevent penetration of local anesthetic- correct by making the area dependent and adding local anesthetic

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Inadequate Analgesia or Anesthesia

Visceral pain can occur even if the epidural is adequate. Visceral afferent fibers travel with the vagus nerve.May increase the level of epidural anesthesia to the thoracic levels with additional local anestheticIV sedatives and opioids may help

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Inadequate Analgesia or Anesthesia- Failed Epidural

Not waiting long enough to let it workCatheter is inserted too far resulting in a “unilateral” block…pull back the catheter 1-2 cm and add local anesthetic with the unaffected side down

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Inadvertent Intravascular Injection

Risk with spinal anesthesia is extremely lowRisk generally lies with epidural or caudal anesthesiaToxicity will affect the central nervous system and cardiovascular system

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Inadvertent Intravascular Injection

Local anesthetics vary in their potential to cause toxicityLeast to most toxic local anesthetics are as follows:Chloroprocaine< lidocaine < mepivacaine < levobupivacaine< ropivacaine < bupivacaine

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Inadvertent Intravascular Injection- Symptoms

HypotensionArrhythmiasCardiovascular collapseSeizuresUnconsciousness

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Inadvertent Intravascular Injection- Prevention

Test doseCareful aspiration prior to injectionIncremental dosingVigilant monitoring for early signs and symptoms of intravascular injectionEarly symptoms include increase heart rate (if epi used), tinnitus, funny taste or metallic taste, subjective changes in mental status

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Inadvertent Intravascular Injection- Prevention

With early symptoms stop administration and anticipate impending complications such as seizures and hypotension, etc.Re-evaluate placement of catheter and reinsert as needed

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Local Anesthetic Toxicity Treatment

Standard ACLS treatmentBretyllium may be more effective than other forms of antiarrhythmics

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On the Horizon- Intralipids

Several successful resuscitations of local anesthetic overdose as well as other lipophilic medication overdosesLocal anesthetics are amphipathic (have an affinity for both lipid and water)This makes local anesthetics potentially toxic for several tissues including the heart, brain, and skeletal muscles

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On the Horizon- Intralipids

Intralipids expand the lipid compartment and allow for local anesthetic binding (there are more involved and technical explanations but lets keep it simple)

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Lipid Rescue Protocol (Experimental)

20% Intralipid1.5 mg/kg initial bolus0.25 mg/kg/min infusion for 30-60 minutesBolus may be repeated 1-2 times for persistent asystoleMay increase infusion rate if blood pressure decreasesSee lipidrescue.com for more information

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Subdural Injection

Subdural space is a potential space that is found between the dura and arachnoid spaceIt contains a small amount of serous fluidSubdural space extends from the epidural space to the intracranial spaceLocal anesthetics can travel further in the subdural space than they can in the epidural space

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Subdural Injection

Small doses of local anesthetic can travel far in the subdural spaceSmall doses of local anesthetic associated with a spinal may result in no local anesthetic blockadeLarger doses of local anesthetics associated with epidural analgesia may result in Horner’s Syndrome

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Subdural Injection

Manifestations of Horner’s syndrome include miosis (constriction of the pupil); ptosis (drooping of the upper eyelid); and anhidrosis (diminished or absent sweating).

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Horner’s Syndrome

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Subdural Injection

Larger doses of local anesthetics associated with epidural anesthesia may result in a total spinal.Prevention is slightly more difficult as aspiration will generally be negativeWith slow incremental dosing you may note a higher and faster progression of blockade than would be normally expected

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Backache

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Backache

Up to 30% of patients undergoing general anesthesia will complain of back painLarge number of patients suffer from chronic back painNot a contraindicationPatient should be aware that spinal or epidural anesthesia may result in some discomfort

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Backache

Inflammatory reaction due to tissue traumaMay result in back spasmsShort lived, analgesics, iceMay last a few weeksBack ache may be a sign of serious complications such as epidural/spinal hematoma, abscessCareful evaluation to determine if a common/benign complication or something more serious

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Postdural Puncture Headache

Caused by disrupting the integrity of the duraCan occur due to: spinal anesthesia, “wet” tap with epidural, epidural catheter migration, tip of the epidural needle “indenting” the dura enough to cause a leak.

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Postdural Puncture Headache

Headache occurs due to leakage of CSF through the duraDecrease in intracranial pressure occurs due to the leakUpright position in the patient leads to traction on the dura, tentorium, and blood vessels resulting in pain.Traction on the 6th cranial nerve can result in diplopia and tinnitus

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Postdural Puncture Headache- Symptoms

Headache associated with upright position (i.e. sitting or standing). Relief found with a supine positionHeadache may be bilateral, frontal, retroorbital and/or occipital with or without radiation to the neckDescribed as “throbbing” or constantMay be associated with nausea and/or photophobia

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Postdural Puncture Headache- Symptoms

Onset is generally 12-72 hours; rarely is the onset immediateIf untreated it may last for weeks

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Postdural Puncture Headache- Associations

Increased incidence related to needle size, needle type and patient populationThe larger the needle the higher the incidenceCutting point needles have a higher incidence of post dural puncture headache than pencil pointsWhen using cutting point needles orientate the bevel “sideways” so it will be parallel with the fibers. This will act to “spread” the fibers as opposed to cutting them

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Postdural Puncture Headache- Associations

Recent literature may indicate that pencil points actually cause more trauma then cutting needles. This actually may reduce the incidence of headache secondary to a localized inflammatory response.Increased post dural puncture headache in younger patients, in female patients, and in pregnant patients

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Postdural Puncture Headache

Some advocate the prophylactic treatment if a wet tap occurs with an epidural needle.Methods include epidural blood patch, epidural dextan, or epidural saline.A wet tap with a 17 g. epidural needle will yield a 50% incidence of pdphA prophylactic epidural blood patch performed within 24 hours of a “wet” tap has a 71% failure rate.After 24 hours there is a failure rate of 4%

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Postdural Puncture Headache

Epidural blood patches are not without risk.Remember 50% of the patients with a “wet” tap will not get a post dural puncture headache.Conservative measure would be to wait and see if symptoms occurProphylactic treatment will only result in unnecessary treatment in 50% of the patients

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Postdural Puncture Headache- Conservative Treatment

Symptoms can be debilitatingStart with conservative measuresSupine position- will reduce symptoms, no evidence that bed rest will reduce the duration of post dural puncture headache. Theoretically it should decrease the amount of CSF leak and allow replacement of lost CSF

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Postdural Puncture Headache- Conservative Treatment

Hydration- theoretically helps to encourage the production of CSF. A dehydrated patient may experience more severe symptoms and hydration is important. The one study looking at this did not find that hydration decreased the incidence of post dural puncture headache.

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Postdural Puncture Headache- Conservative Treatment

Caffeine- theoretically helps to decrease sx by vasoconstriction of the cerebral vessels. May decrease symptoms but does not necessarily decrease the number of patients that will require an epidural blood patch.IV caffeine can be administered in a dose of 500 mgOral caffeine can be encouraged.

A dose of 300 mg of oral caffeine has been shown to decrease the intensity of pdph

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Caffeine Content of Common Beverages

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Postdural Puncture Headache- Conservative Treatment

Analgesics- will decrease the severity of symptoms and include acetaminophen and NSAIDSStool softners and soft diet may help decrease Valsalva straining which may increase leakage of CSF

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Postdural Puncture Headache- Conservative Treatment

Conservative treatment is mainly symptomatic

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Postdural Puncture Headache- Epidural Blood Patch

Definitive treatmentSuccessfully resolves 90% of all post dural puncture headache after the first treatmentGenerally offered 12-24 hours after the initiation of conservative treatmentNot without risk

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Postdural Puncture Headache- EBP Precautions

Check patients history for contraindicationsCheck coagulation statusEnsure no anticoagulants have been administered (i.e. DVT prophylaxis)Ensure that the patient is not bacteremicJehovah’s Witness patients may refuse an epidural blood patch based on religious beliefs

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Postdural Puncture Headache- Epidural Blood Patch

Involves injection of 15-20 ml of the patients own blood at the level of dural punctureMay be administered one space below the dural puncture siteBlood patch works by mass effect and stops the leakage of CSF or alternatively by coagulating and “plugging” the hole

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Postdural Puncture Headache- Epidural Blood Patch

Inform the patient of risks and benefitsSame as with any neuraxial technique with the addition of the increased risk of meningitis or infection (the blood that is removed can be contaminated and placed at an area that has breached the blood brain barrierInform the patient that it is only 90% effective and not 100% effective

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Postdural Puncture Headache- Epidural Blood Patch Technique

Assemble your supplies- mask, sterile gloves, epidural tray, additional betadine and alcohol, sterile needle for venipuncture and tourniquet.Prior to locating the epidural space identify a suitable vein to draw blood. Prep the area with betadine and consider draping the area with sterile towels

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Postdural Puncture Headache- Epidural Blood Patch Technique

Perform usual steps for locating the epidural spaceOnce epidural space is identified then have your assistant aseptically withdraw 15-20 ml of blood. Keep the blood sterile.Ensure no contamination of the blood has occurred

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Postdural Puncture Headache- Epidural Blood Patch Technique

Place 15-20 ml of blood into the epidural space

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Postdural Puncture Headache- Epidural Blood Patch Technique

The patient should not experience pain but may note pressureThe patient should remain supine for 1-2 hoursThe patient should avoid lifting heavy items or straining for 48 hours (thus avoiding the dislodgement of the epidural blood patch

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Neurological Injury

Can be transient or permanentPrevention is done by avoiding trauma to the nerve roots or spinal cordIdentification of appropriate landmarks is essentialAlways document pre-existing neurological deficitsAsk the patient if they suffer from neuropathy, chronic or acute low back pain, motor deficits.

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Neurological Injury

Document concurrent conditions that may contribute to postoperative neuro deficits such as peripheral vascular disease, diabetes, intervertebral disk injury, spinal disorders.Perform subarachnoid anesthesia below L1 in adults and L3 in childrenMultiple attempts will increase the risk of trauma- avoid this by proper positioning, identification of landmarks, and take your time being deliberate when performing neuraxial techniques

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Neurological Injury

If difficulty is encountered do not be afraid to ask another provider to helpIf a paresthesia is encountered make sure it is transient and redirect the needleWhen inserting a catheter or injecting and the patient experiences pain stop. Direct injection into the spinal cord can lead to paraplegia

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Neurological Injury

Document the presence of paresthesia or pain during neuraxial blockadeAlternatively if the neuraxial technique has been performed without any problems document this (i.e. no pain, no paresthesia, etc.)

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If the patient experiences a neuro deficit after neuraxial blockade:

Possible causes include surgical positioningImproper positioning in the post op periodDirect trauma related to surgeryRule out hematoma or abscessOB patients at risk for neuro deficits related to c-sec and vaginal delivery

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Obstetric Causes

Incidence of neurological complications in OB range from 1:2,600-6,400 and often related to difficult deliveries.Prolapse of intervertebral disk and subsequent nerve root compression can occur.

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Obstetric Causes

Injury related to descending head or mid to high forcep use include lumbrosacral injury (L4, L5). Results in foot drop, weakness of hip adduction and quadriceps.Acute hip flexion and retractors during a cesarean section can result in injury to the femoral nerve (L2, L3, L4). Results in quadricep paralysis, abscent patellar reflex, and altered sensation of anterior thigh and medial calf.

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Obstetric Causes

Incorrect lithotomy positioning and retractors during a cesarean section can injury the lateral femoral cutaneous nerve (L2, L3). This will alter sensation on the anterolateral thigh.Incorrect lithotomy position with knee extension and external hip rotation may injure the sciatic nerve (L4,L5,S1,S2,S3). This will result in sciatic type pain (from gluteal area to foot) and the inability to flex the leg.

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Obstetric Causes

Lithotomy position with acute flexion of thigh may lead to injury to the obturator nerve (L2,L3,L4). This may lead to weak or paralyzed thigh adduction.Compression of lateral knee may lead to common peroneal nerve injury (L4, L5, S1, S2). This will result in foot drop and the inability to stand erect.

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Obstetric Causes

Lithotomy positioning may result in injury to the saphenous nerve (L2, L3, L4). Loss of sensation in the medial foot and anteromedial lower leg.

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Document New Neurological Deficits

Is the neuropathy in the distribution of neuraxial blockade? (usually transient)Is there sharp back pain? Leg pain? (severe symptoms may indicate epidural hematoma or Transient Neurological Symptoms)Is there progressive numbness, motor blockade, or sphincter dysfunction? (may be spinal or epidural hematoma)

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Document New Neurological Deficits

Trauma to conus medullaris generally results in sacral dysfunction and you will see:Paralysis of biceps femoral muscleSensory loss of the posterior thigh, perineal area, or great toesBowel and bladder dysfunction

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Document New Neurological Deficits

After evaluation of sx it is reasonable to have a neurological consult

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Spinal/Epidural Hematoma

1:150,000 for epidurals1:220,000 for spinals

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Factors associated with Spinal/Epidural Hematoma

Abnormal coagulation due to disease/medsMultiple attempts at neuraxial blockadeFormation after the removal of the epidural catheter

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Spinal/Epidural Hematoma

Presence of blood in the subarachnoid or epidural space will result in the compression of neural tissueThere is no way to apply pressure and stop the bleeding due to the anatomy.Compression results in ischemia and subsequent injury

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Spinal/Epidural Hematoma Symptoms (generally rapid)

Sharp back and leg painProgression of numbness and motor weaknessSphincter dysfunction

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Spinal/Epidural Hematoma

Rapid diagnosis is essentialMRI/CT scan can diagnose this complicationSurgical decompression must occur in 8-12 from the onset of symptoms to avoid permanent injury

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Meningitis

Meningitis is very rareMust always use strict sterile techniqueAlways wear a mask and change it frequently even in OB

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Meningitis

Most common cause of bacterial meningitis is from contamination of the puncture site by aerosolized mouth particlesViridans streptococcus is the dominant organism and is found in the mouthStresses the importance of masks!

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Meningitis

To a lesser extent skin bacteria can result in meningitisCare should be taken in securing the device with sterile materialsSkin bacteria could track there way into the epidural space

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Meningitis

Presentation is very similar to a post dural puncture headacheException is there is no postural component to the headache, there is generally a fever, and alteration in level of consciousness

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Arachnoiditis

Very rareMore common in the past when supplies where reusedChemical arachnoiditis can occur with intrathecal injection of steroidsLumbar arachnoiditis is more commonly associated with surgical procedures or trauma

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Epidural Abscess

RareIncidence 1:6,500- 1:500:000May develop independent of neuraxial techniques

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Epidural Abscess-risk factors

Back traumaIV drug abuseNeurological surgical proceduresThose associated with neuraxial techniques are commonly due to indwelling epidural cathetersSymptoms develop between 5 days and several weeks

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Epidural Abscess-Stages of Development

Stage 1: back and vertebral pain intensified by percussion. Any patient with back pain and a fever should alert the anesthesia provider to the possibility of an abscessStage 2: progresses to nerve root and radicular pain

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Epidural Abscess-Stages of Development

Stage 3: motor, sensory and/or sphincter dysfunctionStage 4: paralysis and or paraplegia

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Epidural Abscess-Prognosis

Dependent upon when diagnosed, the earlier the betterEpidural catheter should be removed immediatelyTip sent for cultures (not always accurate)Epidural site should be examined for signs and symptoms of infectionBlood cultures should be sent for evaluationAny drainage from the site should be sent for evaluation

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Epidural Abscess-Prognosis/Treatment

Neuro consultMost common agents include staph auerus and staphylococcus epidermisAntibiotic coverageMRI/CTPossible decompression lami

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Epidural Abscess-Prevention

Sterile technique (hat, mask, sterile gloves, hand washing, sterile field, proper prep of the skin etc.)If there is any doubt to contamination, stop and start overIf epidural cath becomes disconnected you must decide whether to aseptically reattach it or remove the catherter

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Epidural Abscess-Prevention

Reduce epidural catheter manipulationMaintain a closed system alwaysUse bacterial filter that comes with the kitRemove the catheter after 96 hours and if needed then replace it with a new one at a new site

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Shearing Off the Tip of the Epidural Catheter

Never attempt to withdraw the epidural catheter through the epidural needleIf you need to remove the catheter remove both the needle and catheter as one unitWhen dc an epidural catheter use steady pressure never jerk the catheterIf difficulty is encountered change the patients positions (i.e. fetal position) to maximize the intervertebral space

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Shearing Off the Tip of the Epidural Catheter

If tip breaks off deep in the epidural space leave it and observe for complicationsIf tip breaks off in the superficial tissue it should be surgically removedA remnant of epidural catheter superficially can lead to infection

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Complications Associated With Medication Toxicity

Systemic toxicity (covered earlier)Transient neurological symptomsCauda equina syndrome

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Transient Neurological Symptoms

Described in 1993Most common after spinal anesthesia/rare for it to occur with epidural anesthesiaSymptoms include LBP with radiation to the legsSx occur after anesthetic has regressed and normal sensation has occurredSx occur from 1-24 hours after normal sensationAlmost any local anesthetic can cause TNS

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Transient Neurological Symptoms- Associated Local Anesthetics

LidocaineTetracaineBupivacaineMepivacainePrilocaineProcaineRopivacaine

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Transient Neurological Symptoms- Associated Local Anesthetics

Most common local anesthetic to cause TNS is lidocaineMost in the anesthesia community have abandoned lidocaine as a spinal anestheticLeaves us with few good choicesProcaine often too short livedPrilocaine has a high incidence of nausea and vomitingMepivacaine has similar profile to lidocaine for both duration and incidence of TNS

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Transient Neurological Symptoms

Unknown mechanism of actionTheorized that lidocaine is more neurotoxic to the unsheathed nerve

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Transient Neurological Symptoms-Contributing Factors

Lithotomy position – may be due to stretching of the lumbrosacral nerve roots and decreased perfusionEarly ambulation after the spinal reason not elucidatedTreatment is symptomatic and generally is short lived

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Cauda Equina Syndrome

Associated with spinal catheters and 5% lidocaineDiffers from TNS in that it is permanent and associated with sphincter dysfunction, sensory and motor deficits, and paresis

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Cauda Equina Syndrome

Generally appears in a peripheral nerve pattern and may be due to misdistribution of the hyperbaric lidocaine

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Cauda Equina Syndrome

Neurotoxicity of local anesthetics is as follows:Lidocaine=tetracaine > bupivacaine > ropivacainePain is similar to nerve root compressionHas been reported after single shot spinals as well as rarely after epidural anesthesia

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Analyzing Complications of Spinal and Epidural Anesthesia

Sweden1990-1999Reviewed 1,260,000 spinals and 400,000 epidurals (half of which were for OB)Overall incidence of complications were 127 out of 1,660,000.Moen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Analyzing Complications of Spinal and Epidural Anesthesia

Incidence for spinal anesthetics 1:20,000-30,000Incidence for epidural in OB was 1:25,000Incidence for non OB epidural was 1:3,600(this differs from US experience)Moen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Analyzing Complications of Spinal and Epidural Anesthesia- Risk Factors

LMWH administered within 10 hours before a spinal or epidural or removing a catheter 2 hours before treatmentDisease that cause coagulation problems such as renal/liver, OB syndrome with hemolysis, elevated liver enzymes, low plateletsAnkylosing Syndrome

Moen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Analyzing Complications of Spinal and Epidural Anesthesia- Risk Factors

Spinal deformityTrauma while during the blockOsteoporosisMoen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Analyzing Complications of Spinal and Epidural Anesthesia

Most complications seen with orthopedic surgery followed by general surgery and then urologyComplications higher after epidural anesthesia when compared to spinal anesthesiaPatients with cauda equina syndrome, traumatic cord injury, and paraplegia had a 100% of permanent injury.

Moen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Analyzing Complications of Spinal and Epidural Anesthesia- The take home

Complications occur 4-5 times more frequently after spinal anesthesia when compared to epiduralOB population had a lower incidence of complications compared to non ob female populationOsteoporosis is now a risk factorSevere complications have a high rate of being permanent

Moen V, Dahlgren N, Irestedt L. Severe neurological complications after central neuraxial blockade in Sweden 1990-1999. Anesthesiology. 2004; 101: 950-959.

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Allergic Reactions

Very low incidence with local anesthetics.Esters are more likely to cause reactions. They are metabolized into PABA (a known allergen).Methylparaben is a preservative used in some multi dose vials and is structurally similar to PABA. Should use preservative free local anesthetics.

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Allergic Reactions

Most reactions are related to vagal reactions, toxicity of local anesthetics, effects of epinephrine such as tachycardia, flushing, and tachypnea.Allergic reactions to anesthetics are rare. Propensity to cause allergic reactions are as follows muscle relaxants> thiopental > propofol > etomidate = ketamine = benzodiazepines > local anesthetics

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Allergic Reactions

Anaphylactic reactions involve in a number of mediators that result in an exaggerated response.Airway- angioedema of upper airway, bronchospasm, and edema of the lower airway. Signs and symptoms include bronchospasm, cough, dyspnea, pulmonary edema, laryngeal edema, and hypoxia. Vascular- increased permeability allows edema to occur resulting in hypovolemia and shock. Primary symptom will be hypotension and shock. 

Heart- hypoperfusion and hypoxemia results in arrhythmias and myocardial ischemia. Coronary vasoconstriction may occur. Tachycardia and arrhythmias are common.  Other vital organs- resulting shock and lactic acidosis leads to additional ischemic trauma.

 

The effect of mediators will manifest

dermatologically

as urticaria, facial edema, and pruritus.

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Allergic Reactions

Treatment includes the following: Stop the administration of the suspected medicationAdminister 100% O2 and consider intubation if the patient is not already intubated.Epinephrine administered in doses of 0.01-0.5 mg IV or IMAdminister fluids rapidly to combat the hypovolemia and shock (1-2 L of crystalloid)Diphenhydramine in a dose of 50-75 mg IVRantidine or

cimetidine IVHydrocortisone up to 200 mg IV or alternatively methylprednisolone in a dose of 1-2 mg/kg IV.

Slide128

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