PharmExamIV Flashcards
What is the other name for neuromuscular monitoring?
Acceleromyography
The most common location, nerve, and muscle monitored are?
hand, ulnar nerve, adductor policis
What are the long acting NDNMBs?
Pancuronium
What are the intermediate acting NDNMBs?
- Rocuronium
- Vecuronium
- Cisatracurium
- Atracurium
What are the short acting NDNMBs?
Mivacurium
What two reversal agents are normally paired together?
Neostigmine and Glycopyrolate
What is the mechanism of action for AChE inhibitors?
Inhibit acetylcholine esterase at the NMJ, so that ACh can bind and cause muscle contraction.
Competitive antagonists
What subunits do ACh bind to?
Alpha
What locations do NMBD reversal agents work at?
Preganglionic (SNS & PNS)
NMJ (primary)
What is the ceiling effect?
The point at which the drug will no longer have any effect
What is the max dose of neostigmine?
5 mg
What is the max dose of Edrophonium
1 mg/kg
How many twitches do we need to see before we can reverse?
1-2 twitches. Muscular blockage cannot be reversed if there are 0 twitches.
What are the 5 factors that influence the reversal of NMB?
- Depth of block
- AChE inhibitor choice
- Dose administered
- Rate of plasma clearance
- Anesthesia agent choice and depth
–> Postoperative residual NM blockade
What is the dose range of neostigmine?
0.04-0.07 mg/kg
OR
40-70 mcg/kg
What’s important to note regarding paralytics and their reversal agents?
The paralytics can last longer than the reversal agents.
What is the onset time of neostigmine?
5-10 minutes
What is the duration of action for neostigmine?
60 minutes
How is glycopyrolate dosed with neostigmine?
0.2 mg per mg of neostigmine
What is the dose for sugammadex?
2-16 mg/kg
What is the onset time of sugammadex?
1-4 minutes
What is the duration of sugammadex?
1.5-3 hours
What is the dose for succinylcholine (Anectine)?
1-1.5 mg/kg
What is the onset of succiynlcholine (Anectine)?
30-60 seconds
What is the duration of action for succinylcholine (Anectine)?
5-10 minutes
What is the dose for pancuronium (Pavulon)?
0.1 mg/kg
What is the onset for pancuronium (Pavulon)?
2-3 minutes
What is the duration of pancuronium (Pavulon)?
60-120 minutes
or
1-2 hours
What is the dose for cisatracurium (Nimbex)?
0.1 mg/kg
What is the onset for cisatracurium (Nimbex)?
2-3 minutes
What is the duration for cisatracurium (Nimbex)?
40-75 minutes
What is the dose for vecuronium (Norcuron)?
0.1 mg/kg
What is the duration for vecuronium (Norcuron)?
45-90 minutes
What is the onset for vecuronium (Norcuron)?
2-3 minutes
What is the dose of edrophonium?
0.5 to 1 mg/kg
What is the onset of edrophonium?
1 to 2 minutes
What is recurarization?
An increase in neuromuscular block after a variable period of recovery.
Patient becomes paralyzed again
If our dosage was 50mcg/kg
How much neostigmine will you administer in mL for a 100kg patient?
Neostigmine is available at 1 mg/mL
What is the renal excretion of the NMBD reversal agents?
Neo, Pyrido, and Edroph
Neo is 50%
Pyrido and Edrop are 75%
What does CRF do to plasma clearance? How does this affect our reversal agents?
Renal failure decreases plasma clearance and increases the duration of action.
What are the primary side effects of NMBD reversal drugs?
Increased nicotinic/muscarinic activty
CV: brady, asystole, arrythmia
Pulm: bronchoconstriction, salivation
GI: PONV, gastric fluid secretion
Eyes: Miosis
What reversal agent is preferred for cardiac disease?
Glycopyrrolate
What anti-cholinergic/anti-muscarinic is given to prevent side effects with Edrophonium?
Atropine: 7-10 mcg/kg
What anti-cholinergic/anti-muscarine is given to prevent side effects with neostigmine and pyridostigmine??
Glycopyrrolate
10 mcg/kg is the dose for this patient
How much neostigmine will you administer in mL for a 100kg patient?
Neostigmine is available at 0.2 mg/mL
What is the mechanism for persistent NM blockade?
Acetylcholinesterase is maximally inhibited and no further anticholinesterase is effective
What is the MoA of sugammadex (Bridion)?
Encapsulates and binds the NMBD molecules
Binds to free drug in the plasma (not proteins)
Forms a concentration gradient using hydrophobic interactions
What is the elimination 1/2 time of Sugammadex (Bridion)?
2 hours
What is the major route of elimination for sugammadex (Bridion)?
Urine
70% in 6 hours
90 % in 24 hours
How are neostigimine and edrophonium cleared if renal function is impaired?
30-50% hepatic clearance
What type of molecule is sugammadex (Bridion)? What are its properties?
γ-cyclodextrin
dextrose units from starch
Highly water soluble
What are dose related sugammadex (Bridion) side effects?
N/V
Pruritis
Urticaria
How do you readminister roc or vec after reversal (up to 4mg/kg bridion)?
Wait 5 minutes and then administer 1.2 mg/kg rocuronium
If NMB is req before recommended waiting time, use nonsteroidal NMBD
What are some contraindications for sugammadex?
- Oral contraceptives
- Toremifene (no-steroidal anti-estrogen) - displaces NMBD from sugammadex
- Heparin - Coagulopathy/Bleeding
- Less than recommended doses - Recurarization
What are the s/s of recurarization?
- Can verbalize - suffocating feeling
- Unable to sustain head lift or hand grasp
- Pharyngeal collapse and respiratory obstruction
How do we treat recurarization?
- Re-sedate patient
- Give additional reversal agents in divided doses (Neo 0.05 mg/kg IV = longer DoA)
What is the clinical duration of response for pancuronium?
86 minutes
What is the clinical duration of response for rocuronium?
36 minutes
Rocky is 36 minutes late
What is the clinical duration of response for vecuronium (Norcuron)?
44 minutes
What is the clinical duration of response for atracurium?
46 minutes
What is the clinical duration of response for cisatracurium (Nimbex)?
45 minutes
What is the clinical duration of response for mivacurium?
16.8 minutes
What preservative is found in both esters and amides that can cause allergies?
Methylparaben
What are the S/S of IgE anaphylaxis?
Rash
Urticaria
Laryngeal edema
hypotension
bronchospasm
What is LAST?
Local Anesthetic Systemic Toxicity
Results from an excess plasma concentration of the drug
Entrance into the systemic circulation
What does LAST depend on?
Dose
Vascularity of site
Epinephrine
Physiochemical properties
What is the order of the blood concentration at LA injection sites from the highest to the lowest?
- IV
- Tracheal
- Caudal
- Paracervical
- Epidural
- Brachial
- Sciatic
- Subcutaneous
ITCPEBSS
What is the dose dependent effect of Lidocane at 1-5 mcg/mL?
Analgesia
What is the dose dependent effect of Lidocane at 10-15 mcg/mL?
Seizures
Unconciousness
What is the dose dependent effect of Lidocane at 15-25 mcg/mL?
Apnea
Coma
What is the dose dependent effect of Lidocane at >25 mcg/mL?
cardiovascular depression
What is the dose dependent effect of Lidocane at 5-10 mcg/mL?
most effects…
Circumoral numbness
Tinnitus
Skeletal muscle twitching
Hypotension
Myocardial depression
How does lidocaine cause cardiovascular affects?
Block cardiac Na+ channels
Slows conduction of cardiac impulses
Prolongs PR interval & causes QRS widening
Which local anesthetic causes the worst cardiovascular system effects?
Bupivacaine
Latches onto cardiac muscle?
Bupivacaine > Ropivacaine > Lidocaine
What two factors predispose our OB population to local anesthetic toxicity?
- Decreased plasma esterases
- Decreased plasma proteins
What are the 3 goals of LAST treatment?
- Prompt airway management
- Circulatory support
- Removal of LA from receptor sites
What drugs are used to treat LAST?
There are several
100% oxygen
Barbituates
Benzodiazepines
Epinephrine
Propofol
Muscle Relaxants
Intralipid
Medications given depends on the symptoms seen
What is intralipid? What is the MoA?
Intralipid is lipid emulsion therapy that creates a lipid compartment. The lipid emulsion acts as a “sink” for the lipophilic (fat-soluble) local anesthetic molecules. The local anesthetic molecules diffuse from the tissues and plasma into the lipid phase of the emulsion, reducing their concentration in the bloodstream and tissues.
If the patient does not respond to intralipid, what is the next step?
CPB/ECMO
What is the dose for intralipid?
1.5 mL/kg of 20% lipid emulsion
0.25 mL/kg/minute infusion for at least 10 minutes
Max dose: 3.8 mL/kg (1.2 to 6 mL/kg) in 30 minutes
16,200 mgs
What are the 3 categories of neural tissue toxicity from LAs?
- Transient Neurological Symptoms (TNS)
- Cauda Equina Syndrome
- Anterior Spinal Artery Syndrome
Either transient or permanent neurological injury
What are transient neurological symptoms?
Moderate to severe pain (lower back, buttocks, & posterior thighs) within 6 to 36 hours after uneventful single-shot SAB
What is the treatment for transient neurological symptoms?
- Trigger point injections
- NSAIDS
What is cauda equina syndrome?
Diffuse injury at the lumbosacral plexus
Varying degrees of: sensory anesthesia, bowel and bladder dysfunction, & paraplegia
Associated w: disc hernation, prolapse, or sequest w urinary retention
What is anterior spinal artery syndrome?
Lower extremity paresis with a variable sensory deficit
The cause is uncertain. It could be a thrombosis or a spasm of the bilateral anterior spinal artery.
Which LAs can cause methemoglobinemia?
Prilocaine > benzocaine > lidocaine
Nitroglycerine, phenytoin, and sulfonamides also cause metHgb
Pril, Benny, and Liddy met
What is the dosage for methylene blue?
1 mg/kg over 5 mintutes (max 7 to 8 mg/kg)
Reversal from ferric Hgb to ferous Hgb is within 20-60 minutes
What are CO2 retainers susceptible to?
Lidocaine depressing the ventilatory response to arterial hypoxemia
What is the primary cause of hepatotoxicity with LAs?
Continuous or intermittent epidural bupivacaine to treat posthereptic neuralgia. Stop the infusion.
What is the MoA of cocaine toxicity?
SNS stimulation by blocking presynaptic uptake of NE and dopamine
Increases postsynaptic levels
What are the adverse effects of cocaine toxicity?
HTN
Tachycardia
Coronary vasospasm
MI
Ventricular dysrythmias
Fetal hypoxemia
Seizures
What are the 4 antiarrythmic drug classes?
Class I - Sodium-channel blockers.
Class II- Beta-blockers.
Class III- Potassium-channel blockers.
Class IV- Calcium-channel blockers.
What is the IV dosage of lidocaine?
1 to 2 mg/kg IV (initial bolus) over 2-4 minutes
1 to 2 mg/kg/hour (drip) terminated 12-72 hours
What is the easy way to remember what class a LA belongs to?
One “i” in the name means that it is an ester anesthetic (Cocaine)
More than one “i” it is an amide (Lidocaine)
What is the molecular structure of lidocaine?
Lipophilic portion (1) connected by a hydrocarbon chain (2) to the hydrophillic portion (3).
The bond between (1) and (2) classifies it as an ester or an amide
What determines whether or not a local anesthetic is a amide or an ester?
The intermediate chain
What is the pH of local anesthetics?
6
Weak bases
What four LAs have a potency of 1?
- Procaine
- Lidocaine
- Prilocaine
- Mepivicaine
Roc, Doc, & Loc me in as #1
What LAs have a potency of 4?
Hint: there are 4
- Chloroprocaine (Rapid)
- Bupivacaine (Slow)
- Levobupivacine (Slow)
- Ropivacaine (Slow)
Chlorbupriva came in 4th
Which two LAs have a rapid onset?
Chloroprocaine
Lidocaine
THE REST OF THE LAs ARE SLOW ONSET
Which local anesthetic is odd man out in terms of potency?
Tetracaine (16!)
What 3 LAs have a duration of 240-480 minutes?
- Bupivacaine
- Levobupivacaine
- Ropivacaine
It’s too far for Mepiva to come here
Which LA has the shortest duration time?
Chloroprocaine
30-45 minutes
Rapid, Potency of 4
Which LA has the 2nd shortest duration?
Procaine
45-60 minutes
potency 1, onset slow
Which anesthetics have durations between 60 and 180 minutes?
Hint: There are 4.
Lidocaine (60-120 min)
Prilocaine (60-120 min)
Tetracaine (60-180 min)
Mepivacaine (90 -180 min)
For the next 60-180 min, I’m your life pilot, tip me!
Which LAs do not have an toxic plasma concentration?
Ester LAs
Ester is not a toxic bitch
What are the pKs of the ester anesthetics? What are they?
Procaine (pK = 8.9)
Chloroprocaine (pK = 8.7)
Tetracaine (pK = 8.5)
Each pK drops by 0.2! (PCT!!)
Which LAs have a pK in the range of 7?
Lidocaine (pK = 7.9)
Prilocaine (pK = 7.9)
Mepivacaine (pK = 7.6)
Li, Pri, and Me are on the 7th floor.
Which LAs all have an pK of 8.1?
- Bupivacaine
- Levobupivacaine
- Ropivacaine
pK = 8.1
Bu, Lev, Ro can park on 8, except Mepiva, cuz she’s a bitch
What are the properties of nonionized drugs?
Faster onset of action
More lipid soluble
Works better
What do liposomes do?
Prolongs duration of action and decreases toxicity of LAs
Liposomal drug delivery improves the therapeutic efficacy of drugs, reduces side effects, and prolongs drug circulation time in the body.
What is the MoA of LAs?
Binds to VG-Na+ channels
Blocks/inhibits Na+ in nerve membranes
What 3 factors affect motor blockade?
- Lipid solubility
- Repetitively stimulated nerve
- Diameter of the nerve
What are other target action sites of LAs besides VG-Na+ channels?
- K+ channels
- Ca2+ channels
- GPCRs
What is MEC?
Minimum Effective Concentration
Similar to MAC for VAs, but for LAs
How many nodes of ranvier do we need to block?
At least 2, preferably 3 (1 cm)
Which nerve fibers are blocked first by a LAs?
Myelinated preganglionic B fibers (SNS)
What nerve fibers are second to be blocked by LAs?
Small and medium sized myelinated A and B
What determines a LA’s intrinsic vasodilator activity?
Potency and DoA
Lidocaine = greater systemic absorption
What effect does the pKa being closer to physiologic pH have on LAs?
More rapid onset
What percentage of LAs are lipid soluble in nonionized form?
50%
LAs are weak bases with pKa values above physiologic pH
What does adding epi to our LAs do?
Increases duration of action
What is the primary determinant of potency?
Lipid solubility
The rate of clearance for LAs depends on what two factors?
- Cardiac Output
- Protein binding: % bound is inversely related to % plasma
How are esters metabolized?
Hydrolysis by cholinesterase enzyme in plasma
Except cocaine by the liver
What is the primary metabolite of an ester LA?
Para-aminobenzoic acid (PABA)
How are amides metabolized?
Microsomal enzymes in the liver
- Most rapid: Prilocaine (Primary)
- Intermediate: Lidocaine & Mepivacaine (IdMediate)
- Slowest: Etidocaine, bupivacaine & ropivacaine (ERB)
What two things need to be kept in mind with pregnant patients?
Lower levels of cholinesterases
Significant transplacental transfer (Ion trapping)
mostly occurs with amides
Which LAs undergo first pass pulmonary extraction?
Lidocaine
Bupivacaine
Prilocaine
LiBuri
Which LA is most protein bound? Least?
- Bupivacaine (95%)
- Lidocane (70%)
- Prilocaine (55%)
Protein binding and arterial concentration are inversely related
Protein Butt Lipper
What is the maximum infiltration dose of lidocaine?
300 mgs plain and 500 mgs with Epi
What is the metabolite of lidocaine?
Xylidide
How is lidocaine metabolized?
Oxidative dealkylation in the liver, then hydrolysis
What is the metabolite of prilocaine? What’s important to note about it?
Orthotoluidine
Converts Hgb into metHgb
What LA is this?
Similar to Lidocaine, except with:
Longer duration of action
Lacks vasodilator activity
Prolonged elimination in fetus & newborn; no OB
Mepivacaine
What LA is this?
Metabolism: aromatic hydroxylation, N-dealkylation, amide hydrolysis, and conjugation
Protein (95%) binding site: α1-Acid glycoprotein
Bupivacaine
What LA is this?
Metabolism: Liver
MOA: inhibits the activity of normal butyrylcholinesterase (plasma cholinesterase) by more than 70%
Dibucaine
What LA is this?
Metabolism: Hepatic cytochrome P450 enzymes
Metabolites: can accumulate with uremic patients
Lesser system toxicity than Bupivacaine
Protein Binding: α1-acid glycoprotein
Ropivacaine
What LA is this?
Metabolism: Plasma cholinesterase (3.5x faster)
Pregnancy decreases plasma cholinesterase by 40%
Chloroprocaine
What LA is this?
Metabolite: PABA, excreted unchanged in urine
Procaine
What LA is this?
Metabolism: Slower than procaine
Tetracaine
What LA is this?
Unique: Weak acid (pKa 3.5)
Uses: Topical anesthesia of mucous membranes:
Tracheal intubation, Endoscopy, Transesophageal echocardiography (TEE), Bronchoscopy
Onset: rapid
Duration: 30 to 60 minutes
Dose: Brief spray (20%) = 200 to 300 mgs
Methemoglobinemia
Benzocaine
What LA is this?
Metabolism: Plasma and liver cholinesterases
Decreased in: Parturients, Neonates, Elderly, Severe Hepatic Disease
Peak: 30 to 45 mins
Duration: 60 minutes after peak
Elimination: Urine (24 to 36 hours)
Caution: Coronary vasospasm, ventricular dysrhythmias, HTN, tachycardia, CAD
Cocaine
What is the maximum dose of methylene blue in mgs for a 120 lbs patient?
Divide by 2, subtract 10% for lbs to kg
What does alkalinization of LAs do?
Increases % of lipid soluble or non-ionized form
Enhances depth
Increases spread
Faster onset
What LA adjuvant is this?
Increased duration of:
Both motor and sensory blocks
First analgesic request after spinal anesthesia
Dexmedetomidine
What LA adjuvant is this?
Increased duration with subarachnoid block with or without opioids.
Magnesium
What LA adjuvant is this?
Prolongs pediatric regional anesthesia duration.
Clonidine & Ketamine
What LA adjuvant is this?
Increased duration either IV or mixed with LA.
Dexamethasone
The __________ of a LA is _________ to the time the drug is in contact with nerve fibers
DoA; Proportional
Toxic effects are _______
additive
Epinephrine as an additive
1:200,000
1,000,000 / 200,000
5 mcg/mL
Epinephrine as an additive
1:500,000
1,000,000 / 500,000
2 mcg/mL
Epinephrine as an additive
1:10,000
1,000,000 / 10,000
100 mcg/mL
Epinephrine as an additive
1:1,000
1,000,000 / 1,000
1000 mcg/mL or 1 mg/mL
Local Anesthetic Strengths
0.25%
2.5 mgs/mL
Local Anesthetic Strengths
0.5%
5 mgs/mL
Local Anesthetic Strengths
1%
10 mgs/mL
What is the dose of this anesthetic
2%
20 mgs/mL
Local Anesthetic Strengths
4%
40 mgs/mL
What are the total mgs for bupivacaine and the total mcgs for epinephrine if the surgeon injects 20 mLs of 0.25% bupivacaine with 1:200,000 of epi?
2.5 mgs/mL bupivacaine x 20 mLs = 50 mgs
5 mcg/mL x 20 mLs = 100 mcg
What is the dosage of bupivacaine with and without epi for infiltration, PNB, epidurals, and spinals?
175 mg alone or 225 mg with epi
What is the dose for lidocaine with or without epi?
300 mgs alone or 500 mgs with epi
What are the 3 clinical uses for lidocaine with epinephrine?
- Infiltration
- PNB
- Epidural
What is the dose for lidocaine in a spinal?
100 mgs
Which three clinical uses for lidocaine is epinephrine not added?
Topical, IV regional anesthesia, and Spinals
112.5 mgs of bupivacaine with epi and 250 mgs of lidocaine with epi were given during a case. What are the percentages of each local anesthetic based on the recommended maximum single dose in mgs?
This is 50% max of both local anesthetics.
50 + 50 = 100
No more can be given.
Where can topical anesthesia be applied?
Mucus membranes of nose, mouth, tracheobronchial tree, esophagus, or GU tract
What is the topical dosage of cocaine, tetracaine, and lidocaine?
Cocaine (4% to 10%) > Lidocaine (2% to 4%), Tetracaine (1% to 2%)
Cocaine causes localized vasoconstriction
What is the order of effect for peripheral nerve block?
- Proximal affected first and then distal
- Proximal comes back first and then distal
- Smallest sensory and ANS fibers first, and then larger motor and proprioceptive axons
What’s different about using topical lidocaine over topical cocaine in the tracheobronchial tree?
Inhalation of lidocaine does not alter airway resistance, but it does cause vasodilation
What’s important to know about transtracheal lidocaine anesthesia?
Squirt all of it at once. Do not squirt as you withdraw.
What is EMLA?
Eutectic Mixture of LA
Lidocaine and Prilocaine 2.5% = 5% LA
Dose 1 to 2 grams/10 cm2 area
Do not use with skin wounds, beware of methemoglobinemia
IV injection of a LA into an extremity isolated from the rest of the systemic circulation with a tourniquet
Sensation and muscle tone dependent on tourniquet
Bier Block
Produced by direct injection of LA into subarachnoid
CSF is confirmation
Preganglionic fibers: Principal site of action
Sensory effect is on same level of denervation
Spinal Anesthesia Block
SNS is 2 spinal segments ______ of sensory
Cephalad
Motor is 2 spinal segments below ______
sensory
How do we dose subarachnoid blocks?
- Height of patient
- Segmental level of anesthesia desired
- Duration of anesthesia desired
What is important for determining the spread of a local anesthetic in the CSF?
Specific gravity
_____ is more important than the concentration of the drug or the volume of the solution injected with subarachnoid blocks
dose
What two drugs are used in tumescent liposuction? What are their doses?
Epi and Lido; 1:100,000 that is highly diluted with 35-55 mg/kg of lidocaine tumescent
What is the dose for glycopyrrolate?
7-15 mcg/kg (1 mg max)
What is the onset of NDNMB in order from fastest to slowest?
- Rocuronium
- Vecuronium
- Pancuronium
- Atracurium
- Mivacurium
- Cisatracurium
RV Pack All Mi Camping gear
RV pack all my camping gear
The closer the pKa is to pH…
50:50; Ionized:Nonionized
What are the ester anesthetics?
Procaine (pK = 8.9)
Chloroprocaine (pK = 8.7)
Cocaine
Benzocaine
Tetracaine (pK = 8.5)
Ester is a PCCT
What is the dosage of sugammadex for an extreme block?
8 to 16 mg/kg
What is the dosage of sugammadex for a deep block?
4 mg/kg
What is the dosage of sugammadex for a moderate block?
2 mg/kg
What are the 5 factors influencing NMBD reversal?
- Intensity of the block
- NMBD used
- Continued volatile anesthetic
- Reversal drug used
- Patient conditions (acidotic, hypothermic)
What type of bond interactions or forces does sugammadex use?
- Intermolecular (Van Der Waals) forces
- Thermodynamic (Hydrogen) Bonds
- Hydrophobic interactions
What was the first local anesthetic?
Cocaine
What were the first synthetic ester and amide anesthetics?
Procaine; Lidocaine
Which anesthetic is the standard to which all others are compared?
Lidocaine
What 3 systems are carefully monitored with IV lidocaine?
- Cardiac
- Hepatic
- Renal
What anesthetics can utilize liposomes?
- Bupivacaine
- Lidocaine
- Tetracaine
BLT are fatty
What is Exparel?
Bupivacaine ER
Liposomes containing bupivacaine
Lasts up to 96 hours
What anesthetics do not have a significant amount of transplacental transfer?
Esters
Which amide(s) are most rapidly metabolized?
Prilocaine
Which amides are intermediately metabolized?
- Lidocaine
- Mepivacaine
idermediate
What amides have the slowest metabolism?
- Etidocaine
- Ropivacaine
- Bupivacaine
ERB
What is the peak and duration of cocaine?
Peak: 30-45 minutes
Duration: 60 minutes after peak
What is the average pKa of LAs?
8
Alkalinization improves the onset of action in peripheral and epidural blocks by how much time?
3 to 5 minutes
What effect do vasoconstrictors have on the rate of onset for LAs?
No effect
_______ effects may have some degree of analgesia
a-adrenergic
What is the purpose of using topical cocaine?
Cocaine causes localized vasoconstriction which:
1. Decreases blood loss
2. Improves surgical visualization
What is EMLA contraindicated with?
Amide allergies
Achieved by LA injection into tissues surrounding individual peripheral nerves or nerve plexuses
Peripheral Nerve Block
What is the MoA for a PNB?
Diffusion from the outer mantle to the central core of nerve along a concentration gradient
What is the point of a eutectic mixture?
Improves the solublity of drugs by combining them
How long does it take before you can do skin grafting with a eutectic mixture?
2 hours
How long does it take before you can do cautery of genital warts, venipicture, lumbar puncture, arterial cannulation, and myringotomy with a eutectic mixture?
10 minutes
In peripheral nerve blocks…
Duration depends on
dose of local anesthetic
In peripheral nerve blocks…
onset depends on?
pK of the local anesthetic
What are the 4 examples of PNBs provided by Castillo?
- Interscalene
- Axiallary
- Femoral
- Sciatic
What LA is most commonly used in a Bier block?
Lidocaine
What are the steps of a bier block?
- IV start
- Exsanguination
- Double cuff
- LA injection
- IV D/C
What is the blockade sequence in neuraxial anesthesia?
- SNS
- Sensory
- Motor
What confirms a spinal anesthesia block (SAB)?
CSF
What is the principal site of action for a SAB?
Preganglionic fibers
What is the most commonly used anesthetic in epidural anesthesia?
Lidocaine
When will the epidural have an effect on the fetus?
24 to 48 hours
What is the normal onset of an epidural?
15 to 30 minutes
What component of the local anesthetic is required for a conduction block?
Non-ionized form
True or False
In general, the more lipid soluble the local anesthetic is, the greater its potency.
True
Which local anesthetic property is most important when it comes to duration of action?
protein binding
What four things can affect duration of action?
- Protein binding
- Lipid solubility
- Metabolism
- Clearance
What is more acceptable as an additive to both epidurals and SABs?
Opioids
What is one of the differences between epidurals and SAB?
No differential zone of SNS
In a SAB, 5 ft is equal to _____
1 mL
In SAB, for every inch above 5ft you add
0.1 mL
How many people will have an allergic reaction from a LA?
Very rare
<1%
What anesthetics cause more allergic reactions?
Esters
What promotes seizures with LAs?
Hyperkalemia
What is the duration of rocuronium?
35 to 75 minutes
What peripheral nerves are myelinated?
A-a
A-b
A-gamma
A-delta
B
What peripheral nerve fibers have a sensitivity of 1 to procaine?
A-a
A-b
A-gamma
What peripheral nerve fiber is this?
Innervation of skeletal muscles
Proprioception
A-alpha
What peripheral nerve fiber is this?
Touch
Pressure
A-beta
What peripheral nerve fiber is this?
Skeletal muscle tone
A-gamma
What peripheral nerve fiber is this?
Fast pain
Touch
Temperature
A-delta
What peripheral nerve fiber is this?
Preganglionic autonomic fibers
B
What peripheral nerve fiber is this?
Slow Pain
Touch
Temperature
Postganglionic sympathetic fibers
C
What peripheral nerve fiber(s) have a 0.5 sensitivity to procaine?
A-delta
C
What peripheral nerve fiber(s) have a 0.5 sensitivity to procaine?
B
What is the duration of action of all the muscle relaxants from shortest to longest?
- Succinylcholine (5-10 min
- Rocuronium (35-75 min)
- Cisatracurium (40-75 min)
- Vecuronium (45-90 min)
- Pancuronium (60-120 min)
SR or MR CVP
What are the pKs of Lidocaine, Prilocaine, and Mepivacaine?
Lidocaine (pK = 7.9)
Prilocaine (pK = 7.9)
Mepivacaine (pK = 7.6)
What anesthetics have pKs above 8?
Bupivacaine (pK = 8.1)
Levobupivacaine (pK = 8.1)
Ropivacaine (pK = 8.1)
Procaine (pK = 8.9)
Chloroprocaine (pK = 8.7)
Tetracaine (pK = 8.5)
ALL EXCEPT Li, Pri, & Me
What are the pKs of Lidocaine, Prilocaine, and Mepivacaine?
Lidocaine (pK = 7.9)
Prilocaine (pK = 7.9)
Mepivacaine (pK = 7.6)
Li, Pri, and Me are on the 7th floor
How long does MetHgb reversal take after giving methylene blue?
20-60 minutes
What’s another possible reversal for mivacurium?
Purified human plasma cholinesterase
What is toremifene? What’s important to know about it?
Non-steroidal anti-estrogen
Can displace NDMB from sugammadex
Protein binding is equal to….
rate and degree of diffusion
How much 8.4% NaHCO3- is added to 30 mL of LA?
1 mL
Which combination of LAs has a rapid onset and tachyphylaxis
Chloroprocaine and Bupivacaine
What is the dose for regional anesthesia with lidocaine and epineprhine?
7 mg/kg
What is the tissue buffering system?
1 gm SQ tissue can absorb up to 1 mg of lidocaine
What is the plasma peak s/p injection?
12-14 hours
How much SQ infiltration can occur with tumescent liposuction?
5 L
Glycopyrrolate is administered slowly over….
2-5 minutes
Which type of medication is given first during reversal?
Anti ACh drug
Sugammadex is contraindicated in…
patients on dialysis
What NMBD are not reversed by sugammadex?
- Atracurium
- Mivacurium
- Cisatracurium
AMC
How much epinephrine do you give with intralipid therapy?
10 to 100 mcg
What are the predisposing factors for cardiovascular system effects with LAs?
- Pregnancy
- Arterial hypoxemia
- Beta blocker, digitalis, Ca2+ (cardiac drugs)
- Epinephrine & Phenylephrine
How long is the recovery time from TNS?
1 to 7 days
What is the order of lipid solubility of lowest to highest?
- Procaine
- Prilocaine
- Mepivacaine
- Lidocaine
- Bupivacine
- Tetracaine
Pro Players Major League Baseball Tall
What is the order of protein binding (%) from lowest to highest
- Procaine
- Prilocaine
- Lidocaine
- Tetracaine
- Mepivacaine
- Ropivacaine
- Bupivacaine
- Levopbupivacaine
PPL Tell MR B Lies about protein binding
What nerve fibers are last to be blocked by LAs?
C
Which populations have decreased plasma cholinesterases????
- old people
- neonates
- pregnant people
- severe hepatic disease