Spinal/Epidural Random things Flashcards by Elizabeth Hurring

Desired Dermatomal Levels for Peri-anal/anal surgery (“saddle block”)

S2-S5

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Desired Dermatomal Levels for Foot/Ankle Surgery

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Desired Dermatomal Levels for thigh/lower leg/knee

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Desired Dermatomal Levels for vaginal delivery/uterine/hip procedure/tourniquet/ TURP

T10 (level of the umbillicus)

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Desired Dermatomal Levels for scrotum

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Desired Dermatomal Levels for Penis

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Desired Dermatomal Levels for Tsticular Procedure

** Testicles are embryonically derived from the same level as the kidneys for pain transmission (T10-L1)

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Desired Dermatomal Levels for Urology, gynecologic, and lower extremities

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Desired Dermatomal Levels for Cesarean section and upper abdominal

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Target: LA acts on the myelinated preganglionic fibers of spinal nerve roots

Spinal

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Target for ____: LA diffuse through the dural cuff to reach nerve roots

Epidurals

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With epidurals, the LA can leak through the ____ ____ into the para-vetebral area

intervertebral foramen

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Baricity, pt position, dose, site of injections are _____ factors that affect the spread of LA in spinals

Controllable factors

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Volume of CSF, increased intra-abdominal pressure (obesity, pregnancy), elderly are ____ factors

non-controllable factors that affect the spread of LA. in spinals

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T or F: These things effect the spread of LA in spinals

-Barbotage (repeated aspiration and reinjection of CSF)

-speed of injection

-orientation of bevel

-addition of vasoconstictor
-gender

False: these do not affect the spread

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Low or High CSF volume correlates to extensive spread of LA in intrathecal space

low CSF volume (think less dilution)

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During pregnancy, CSF volume _____ dt increased intra-abdominal pressure

decreases

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With age, neural nerves are ____ to LA and SCF volume ____

nerves are vulnerable to LA

CSF decreases

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Factors that affect LA distribution and block height with epidurals:

These are _____ factors that have a significant effect on spread:

-Local anesthetic volume

-Level of injection

-LA dose

controllable

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Factors that affect LA distribution and block height with epidurals:

These are _____ factors:

pregnancy and old age

non-controllable factors

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Factors that affect LA distribution and block height with epidurals:

These are _____ factors that have a small effect on spread:

-LA concentration

-pt position

controllable factors

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Factors that affect LA distribution and block height with epidurals:

These are _____ factors that have a small effect on spread:

-Height

Non-controllable Factors

Taller or shorter stature may slightly affect spread

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Additives in the anesthetic might change ____ or ____ but not spread

onset or duration

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(epidurals)
Injections of LA in the lumbar region mostly spread _____

cephalad

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(epidurals) Injections of LA in the mid-thoracic region spread is ____

balanced both cephalad and caudal

(epidurlas) Injections of LA in the cervical region spreads

caudal

Nerve Fiber: myelination and function? A alpha

heavily myelinated function: skeletal muscle- motor proprioception

Nerve Fiber: myelination and function? A beta

Myelination: heavy Function: touch pressure

Nerve Fiber: myelination and function? A gamma

Myelination: medium Function: skeletal muscle- tone

Nerve Fiber: myelination and function? A delta

Myelination: medium Function: fast pain, temperature, touch

Nerve Fiber: myelination and function? B

Myelination: light Function: preganglionic ANS fiber

Nerve Fiber: myelination and function? C (sympathetic)

Myelination: no Function: post-ganglionic ANS fibers

Nerve Fiber: myelination and function? C (dorsal root)

Myelination: no Function: slow pain, temperature, touch

Order of blockade: first to last

1st: B fibers 2nd: C fibers 3rd: A delta and A gamma 4th: A beta and A alpha

Monitoring sensory block: order of progression?

temp, then pain, then touch/pressure

Monitoring Motor block: Modified Bromage Scale What level is this? -Complete motor block. The patient cannot move the legs, knees, or feet

Monitoring Motor block: Modified Bromage Scale What level is this? No motor block

Monitoring Motor block: Modified Bromage Scale What level is this? -The patient cannot raise an extended leg or move the knee but can move the feet

2: moderate motor block

Monitoring Motor block: Modified Bromage Scale What level is this? The pt cannot raise an extended leg but can still move the knees and feet

1: slight motor block

The Modified Bromage Scale specifically evaluates the function of ______ nerves, which are the lower spine and sacral nerve areas, and does not assess movement above these regions.

lumbosacral

Neuraxial Anesthesia can drop SVR by __ % in healthy people or ___% in elderly or cardiac pt's

healthy: 15% elderly or CV pt's: 25%

Neuraxal anesthesia --> decrease HR triggering two reflexes. What are they?

Bezold-Jarisch Reflex Reverse Bainbridge Reflex

This reflex responds to ventricular under-filling, potentially leading to a significant bradycardia and asystole **This reflex is mediated by 5-HT3 receptors in the vagus nerve and ventricular myocardium

Bezold-Jarisch Reflex ** give ondansetron before procedure

This reflex is triggered by reduced stretching of heart's right atrium to allow for more filling

Reverse bainbridge reflex

cardiac accelerators are?

T1-T4

Nerve that feed the diaphragm?

Phrenic nerve C3-C5

Sudden cardiac arrest after neuraxial anesthesia is more common in spinals and can occure _ - _ min after onset of spinal

20-60 mins after onset of spinal

prevention of spinal-anesthesia induced Hypotension Co-loading: administering intravenous fluids (around 15 ml/Kg) before or after spinal

after ** avoid excess fluids --> it can overlaod the circulatory system, especially pt's with heart conditions

Pulmonary effects of Neuraxial anesthesia: usually minimal impact How is tidal volume, RR, inspiratory reserve volume, ABG, and ERV effected?

All are unchanged besides ERV ** this is due to a small decrease in vital capacity dt loss of abdominal muscle contribution in forced expiration

High concentrations of local anesthetics in the spinal fluid rarely cause nerve paralysis that stops breathing. Typically apnea is due to reduced blood flow to the _____ affecting the brain's breathing center

brainstem

What two populations should you take special considerations in before giving neuraxial anesthesia

COPD and Pickwickian syndrome It is very common to feel short of breath after receiving neuraxial anesthesia dt the loss of sensory feedback from the chest area, with these patients they have lose ability to take big breaths and strong cough

GI Parasympathetic ____: tonic contractions, sphincter relaxation, peristalsis, and secretion.

EFFERENT

GI Parasympathetic _____: transmits sensations of satiety, distension, and nausea

AFFERENT

Sympathetic innervation of GI tract stems from ___ - ___

T5-L2

Sympathetic ____: transmit visceral pain Sympathetic ____: inhibit peristalsis and gastric secretion and cause sphincter contraction and vasoconstriction

AFFERENT EFFERENT

Neuraxial anesthesia effects on Genitourinary no change in renal blood flow with maintained MAP; however a block above ___ affects bladder control

T10

An addition of neuraxial opioids leads to a ___ in detrusor contraction --> increase in bladder capacitance

decrease *** these changes lead to urinary rention/incontinence and need for foley catheter with neuraxial anesthesia

Neuraxial blockade can ____ suppress (major invasive surgery) or ___ block (lower extremity) neuroendocrine response. *** Maximal benefits occurs if the neuraxial blockade occurs before the surgical stimulus

partially suppress major invasive surgery totally block lower extremities

LA Pharmacology: Aromatic ring is lipophilic or hydrophilic

Aromatic ring: lipophilic Tertiary amine is hydrophilic and accepts protons

LA pharm: Intermediate chain determines 3 things

allergic potential, metabolism, drug class

Esters: in the intermediate link connect to an ___ Amides: in the intermediate link coonect to ___

esters: oxygen (C O O) amides: NH (NH C O)

Benzocaine Cocaine Chloroprocaine Procaine Tetracaine

Esters

Bupivacaine Dibucaine Lidocaine Mepivacaine Ropivacaine

Amides

There are cross sensitivities in amino- ____ dt producing para-aminobenzoic acid (PABA)

esters

Amide allergic reaction is rare and has _______ preservative

methylparaben

T or F: There is cross-sensitivity btw esters and amides

False

pKA determines

onset of action

Lipid solubility determines

Potency

The duration of action is determined by

Potein binding (alpha-1 acid glycoprotein)

Site of Injection Tissue blood flow Physiochemical Properties Metabolism Addition of vasoconstrictor

factors influencing vascular uptake and plasma concentration of LA

Baricity chart

SAB Dosing Bupivacaine 0.5-0.75% Dose (T10) Dose (T4) Onset duration Duration + epi

Dose (T10): 10-15 mg Dose (T4): 12-20 mg Onset : 4-8 mins duration: 130-220 Duration + epi: + 20- 50%

SAB Dosing: Levobupivacaine 0.5% Dose (T10): Dose (T4): Onset: duration: Duration + epi: NA

Dose (T10): 10-15 mg Dose (T4): 12-20 mg Onset: 4-8 mins duration: 140-230 mins Duration + epi: NA

SAB Dosing: Ropivacaine 0.5-1% Dose (T10) Dose (T4) Onset duration Duration + epi

SAB Dosing: Ropivacaine 0.5-1% Dose (T10): 12-18 mg Dose (T4): 18-25 mg Onset: 3-8 mins duration: 80-120 mins Duration + epi

SAB Dosing: 2- Chloroprocaine 3% Dose (T10): Dose (T4): Onset : duration: Duration + epi: NA

SAB Dosing: 2- Chloroprocaine 3% Dose (T10): 30-40 mg Dose (T4): 40-60 mg Onset : 2-4 mins duration: 40-90 mins Duration + epi: NA

SAB Dosing: Tetracaine: 0.5-1.0% Dose (T10) Dose (T4) Onset duration Duration + epi

Tetracaine: 0.5-1.0% Dose (T10): 6-10 mg Dose (T4): 12-16 mg Onset : 3-5 mins duration: 90-120 mins Duration + epi: +20-50%

Incremental dosing with __ mL avoids: Accidental "high spinal" Hypotension from rapid autonomic blockade (cardiac arrest) Local anesthetic toxicity

5 mL

If epi is added to epidurals, it can act as a ___ marker

intravenous

Epidural onset

10-25 minutes onset

2-Chloroprocaine comes in 2% and 3% (surgical anesthesia); rapid onset and metabolism; redose q ___ mins

45 mins

Alkalinization of LA in epidurals increases the pH of LS, increasing the concentration of nonionized free base, rate of diffusion, and onset. How much bicarb do you add?

1 meq/10 mL of LA

_____ of the LA is crucial for determining how high the anesthetic block reaches in epidurals.

Volume

Initial Dose: Typically, ______ per segment of the spine to be anesthetized.

1 - 2 mL

Top-Up Dose: Should be _____ of the initial dose, used to maintain the block without letting it wear off too much.

50% - 75%

Timing for Top-Up Dose: Administer before the block decreases more than _____ dermatomes.

2 dermatomes.

With epidurals comparing lumbar vs thoracic, which one would have the greatest spread?

thoracic will have a greater spread bc it is smaller

The concentration of LA in a epidural affects how ___ or ___ the block is

dense or strong the block is

Neuraxial Adjucts: Adjucts can provide postoperative analgesia, extends duration, and improves the density of the block -Opioids do what? -Alpha-2 agonist do what? -Vasopressors do what?

Opioids (Sufentanil, Fentanyl, and Morphine): NO extension of duration (Analgesia/Density: YES) Alpha-2 agonists (Dexmedetomidine IV or IT*, Clonidine): Improves density, duration, and analgesia Vasopressors: Extends duration only; No effect on density or analgesia

Neuraxial opioids target the ______ ______ of the dorsal horn (Lamina 2)

substantia gelatinosa

Neurotransmission is reduced by decreased ____ --> decreased Ca++ conductance and ____ K+ conductance

cAMP and increases K+ conductance

Morphine, hyrdromorphone and meperidine (demerol) are hydrophilic or hydrophobic

hydrophilic --> so duration in longer in CSF and spreads widely affecting larger area for pain relief (more rostral spread)

Neuraxial (hydrophilic ) opioid adjunct onset longer: takes __ - ___ mins to start working duration: last longer (___-___) hrts

onset: 30-60 mins duration: 6-24 hrs

Neuraxial (hydrophilic ) opioid adjunct systemic absorption is ____

Less, it stays longer in CSF

Fentanyl and Sufentanil hydrophiic or lipophilic

lipophilic

high risk and intrmediate risk procedures Hold aspririn for __-___ days low risk procedures generally do not need to hold

4-6 days *** no distinction in guidelines btw 81 mg and 325 mg dose

Consideration for NSAID High risk procedures: hold for __ half lives Intermediate risk procedures: consider holding for cervical ESI (epidural sterioid injections) and _____ _____ block low risk procedures: Central neuraxial blocks:

high: 5 half lives Intermediate: stellate ganglion block low: do not need to routinely hold central: no additional precautions

This drug class inhibits platetl aggregation via surface receptors ex. Tirofiban (Aggrastat); Eptifibatide (Intergrilin), Abciximab (ReoPro)

Glycoprotein IIb/IIIA antagonists

Glycoprotein IIb/IIIA antagonists -Tirofiban and eptifibatide hold for __-__ hrs -Abciximab hold for __-___ hrs

-Tirofiban and eptifibatide hold for 4-8 hrs -Abciximab hold for 24-48 hrs

thienopyridine derivatives inhibits plt aggregation by blocking ____ transferase ex. Clopidogrel (Plavix), Prasugrel (Effient), Ticlopidine (Ticlid)

ADP

Regional anesthesia consideration for thienopyridine derivatives Clopidogrel: Hold for _-_ days. Prasugrel: Hold for _-_ days. Ticlopidine: Hold for __ days.

Clopidogrel: Hold for 5-7 days. Prasugrel: Hold for 7-10 days. Ticlopidine: Hold for 10 days.

Unfractionated heparin potentiates _____ (enzyme inhibitor), inhibiting thrombin (factor 2) and factors 9, 10, 11, 12.

antithrombin

Regional Anesthesia Consideration for unfractionated Heparin Low-dose (<5,000 U): Hold __ - ___hours. Higher-dose (≤20,000 U daily): Hold __ hours. Therapeutic dose (>20,000 U daily or in pregnant patients): Hold __ hours. UFH >4 days should have a platelet count before central neuraxial block

Low-dose (<5,000 U): Hold 4-6 hours. Higher-dose (≤20,000 U daily): Hold 12 hours. Therapeutic dose (>20,000 U daily or in pregnant patients): Hold 24 hours. UFH >4 days should have a platelet count before central neuraxial block

LMWH inhibits ___ ex. Enoxaparin (Lovenox), Dalteparin (Fragmin), Tinzaparin (INNOHEP)

LMWH Regional anesthesia Consideration: -Ensure coagulation status appears normal. -No other blood thinners should be in use. -Check platelet count if on LMWH for more than __ days.

4 days

LMWH Regional anesthesia Consideration: Delay at least ___ hours after a prophylactic dose. Delay at least __ hours after a therapeutic dose. *Consider checking anti-factor 10a activity in elderly or if renal insufficiency.

12 hrs (prophylactic dose) 24 hrs (therapeutic dose )

Vitamin K dependent clotting facotrs (4)

2, 7, 9, 10

Warfarin is a vitamin K antagonist You hould hod for __ days and verify what lab

5 day; INR < 1.5

Thrombolytic agents activate what? ex. TPA; streptokinase, alteplase, urokinase

plasminogen

This class of drug is an absolute contraindication to neuraxial anesthesia

thrombolytic agents

Direct oral anticouagulants inhibit ___ ex. Apixaban (Eliquis), Betrixaban (Bevyxxa), Edoxaban (Lixiana), Rivaroxaban (Xarelto), Dabigatran (Pradaxa) How long should you dc drug before block?

10a; 72 hrs if less than 72 hours check anti-factor 10a

Being young, female, and pregnant are all factors that increase risk of what?

PDPH: post-dural puncure headache

what needle used is mostly responsible for PDPH?

Quincke

Bed rest NSAIDs Caffeine Epidural Blood Patch Sphenopalatine Ganglion Block (SGB) These are all tx for _____

PDPH

What two LA & concentrations are used for spenopalatine ganglion block

Lindocaine 1-2% Bupivacaine 0.5* leave it in for 5-10 mins

If a spinal has not set up after __-__ mins, it may be necessary to redo the block

15-20 mins

Streptococcus viridans

common bacteria involved in post-spinal bacterial meningitis found in the mouth and hands --> wash hands and wear a mask

This skin prep is neurotoxic and can cause arachnoiditis if not completely dry before starting a spinal

chlorhexidine

Cauda Equina Syndrome: -Nerves affected __-___ + coccygeal nerves

L1-S5

Cauda Equina Syndrome: factors that increase risk (3 things)

high Concentration Local Anesthetics: Using 5% lidocaine in SAB Microcatheters: These catheters deliver the drug on a small area, increasing risk of nerve damage by exposing the area with a high concentration of LA. Whiticare 25/26 needle have been associated with this syndrome

These are all signs of what condition: Serious neurologic complication that can be permanent Bowel and Bladder Dysfunction Sensory Deficits: Loss of feeling in the legs or feet. Back pain Saddle anesthesia Sexual dysfunction Weakness or Paralysis Can lead to paraplegia (late sign)

Cauda equina syndrome * if a compressed disc is cause of issue --> immediate laminectomy < 6hrs

This condition leads to pain within 6-36 hrs after surgery and lasts from 1-7 days. It is severe radiuclar pain in the back and buttocks that spreads down both legs

Transiet Neurological symptoms

Tx for this condition include: NSAIDs (ibuprofen), opioids, and trigger point injections

Transiet Neurological symptoms

All of these are risk factors for epidural ____ ____ Multiple Attempts Pregnancy Catheter Type: Stiffer catheters are harder to maneuver and more likely to puncture a vein. Trauma to epidural vein during block procedure

epidural vein cannulation

Local anesthetic systemic toxicity (LAST) is most commonly caused by inadvertent injection LAST is more common in what procedure

peripheral nerve blocks > epidurals

Most frequent symptom of LAST is ___; but with bupivacaine ____ ____ may come first before seizures

seizures; but with bupivacaine cardiac arrest may come first

PLASMA CONCENTRATION (MCG/ML) -Analgesia:

1-5

PLASMA CONCENTRATION (MCG/ML) -Tinnitus; skeletal muscle twitching, numbness of lips and tongue; restlessness; vertigo; blurred vision; hypotension; myocardial depression

5-10

PLASMA CONCENTRATION (MCG/ML) -sizures; loss of contiousness

10-15

PLASMA CONCENTRATION (MCG/ML) coma and respiratory arrest

15-25

PLASMA CONCENTRATION (MCG/ML) cardiovascular collapse

> 25

With LAST these 3 things increase risk of CNS toxicity

hypercarbia, hyperkalemia (more excitable neurons); metabolic acidosis (lowers seizure threshold)

Difficulty of cardiac resusitation from greatest to least (LAST)

bupivacaine > levobupivacaine > ropivacaine > lidocaine

TX LAST: >70 kg <70 kgs

>70 kg : 100 mg bolus over 2-3 mins --> 250 mg infusion over 15-20 mins <70 kgs: Start with a 1.5 mL/kg bolus for 2-3 minutes of 20% lipid emulsion, followed by a 0.25 mL/kg/min infusion. Repeat or double if unstable. max dose is 12 mg/kg

These drugs should be avoided in what tx? beta blockers LA, vasopressin CCB

LAST

Once pt is stable after receiving lipid emulsion, how long do you keep infusion going?

At least an edition 15 mins

Quicke and Pitkin are consider what types of spinal needles

cutting

PT (prothrombin time) normal lab value

12-14 secs

INR (international normalized ratio) lab value

0.8-1.1

aPTT: activated parial thomboplastin time

25-32 secs

PLT count

150,000-300,000

extrinsic pathway: factors and labs

III and VII coumadin (warfarin): PT &I NR

intrinsic pathway: factors and labs

12,11,9, 8 labs: PTT & ACT

Common pathway for extrinsic and intrinsic clotting cascade

10, 5, 2, 1, 13