Nagelhout Local Anesthetics 2 - Exam 2 Flashcards
T/F Pregnancy enhances the effects of LA.
true
-more sensitive to LA
T/F Epidurals, even when placed properly, can cause decreased uterine tone, slows labor, and affects uterine/ umbilical blood flow
FALSE
T/F If a pt with preeclampsia receives repeated epidural injections of lidocaine, they can develop greater accumulation of LA
true
Which LA drug has greater cardiotoxicity, predisposing it to causing ventricular arrhtyhmias?
Bupivacaine
T/F Ropivacaine and Levobupivacaine can cause even higher cardiotoxic effects than standard racemic bupivacaine
false
T/F LA are teratogenic
false
Fetal acidosis results in a greater accumulation of _ (amide/ester) LA in the fetus
amide
The elimination half life of amide LA is _ (shorter/longer) in newborns than in adults
longer
-fetuses have larger volume of distribution, ALSO more acidotic
T/F Compared to adults, fetuses and newborns are more vulnerable to the toxic effects of LA
false
T/F Neonatal neurobehavior solely depends on the choice of LA
false
Alkalinization of LA solutions _ (shortens/lengthens) the latency of neural blockade but increases the risk of _ when giving epidurals.
shortens the latency (speeds onset)
HoTN
Neuraxial opioid anesthesia produces analgesia without the loss of _ or _
sensation or proprioception
Combining neuraxial LA and opioids _ (increases/decreases) block density and allows for admin of a _ (higher/lower) total dose of LA
increases
lower
-reduces S/E risk too!
Spinal bioavailability of hydrophilic drugs (morphine and hydromorphone) are _ (more/less) than hydrophobic drugs (fentanyl, sufentanil)
less
3 most common S/E of neuraxial opioid admin are:
-pruritis
-N
-V
-fetal bradycardia and maternal resp depression are the most serious tho
What is the benefit of mixing 2 different LA?
-helps speed onset and prolong duration when done properly
Mixing LA compensates for the _ duration of short -acting agents (Lido, chloroprocaine) and the _ latency of long-acting agents (Tetracaine, Bupivacaine)
short
long
Use of _ techniques for regional anesthesia make it possible to give a rapid acting LA then start a short or long acting infusion.
catheter
T/F Due to LA toxicities being different between drugs, when mixing them, you are able to give both max doses.
FALSE!
-cut toxic doses to whatever % of the total mix solution
ex) you want a 50/50 bupivacaine and lidocaine solution: give 3.5 lidocaine and 1.5 bupivacaine
T/F Spread and depth of LA is less in pregnant pts than nonpregnant pts
false
-pregnant pts have LA spread more and works more significantly
-why?: mechanical and hormonal change-most likely a hormonal factor
T/F LA doses should be cut in pregnant pts, but especially in their 1st trimester
true
-hormone changes(progesterone) are the most significant factor increasing the spread/depth of LA, NOT gravid uterus
If you give a max dose of a spinal LA at the start of a procedure for a patient, and the surgeon asks if they can give some more 1.5 hr into the case, can they give more LA?
yes
-can safely readminister LA 90 mins after the max dose is given
Tumescent anesthesia, known for its use during liposuction, is more common with _ _ procedures in NORA settings
minimally-invasive
Tumescent anesthesia involves injecting lidocaine into fat during liposuction at doses of _ - _ mg/kg.
35-55mg/kg
-conc can peak 12-16 hr after infusion
How is giving 35-55mg/kg of LA for liposuction ok when max dose of Lido with epi is 7mg/kg?
It’s directly injected into fat, which has less vasculature. This helps constrict the vessels in there to avoid trauma while the surgeon sucks the rest of the fat out
Without liposuction, tumescent anesthesia max dose of lidocaine is _ mg/kg
28mg/kg
When using tumescent anesthesia for endovenous laser therapy (varicose vein therapy) , peak lidocaine conc are seen much earlier between _ - _ hr after injection
1-2
Tumescent Anesthesia LA risks:
-higher conc LA
-rapid injection
-perivascular injection
-removing epi from the LA formula
Tumescent anesthesia preparation:
0.9: 1 L
sodium bicarb: 12mEq (12.5mL of a 8.4% amp)
Epi: 1mg
Lidocaine: 500mg
Eutectic mixture of lidocaine and prilocaine (EMLA) is most often used for:
topical numbing kids hands for IV start
-little numbing bandaid they wear on the way to the hospital
Lidocaine-Epinephrine-Tetracaine (LET) main uses:
-topical numbing for suturing kids lacerations (also tetracaine-epi-cocaine [TAC])
- numbing endotracheal area before intubation
Tetracaine- Epi-Cocaine max safe dose
-adults
-kids
A: 3-4mL
K: 0.05mL/kg
What does hyaluronidase (HSE) do naturally?
naturally occurring enzyme in tissue that helps stuff spread around in tissue/skin
-good for ophtho cases for one time LA injections into eyeball
What does HSE do for LA?
-faster onset
-shorter duration
-higher risk toxicity (d/t spread)
What is process of forming catecholamines?
- Phenylalanine
2.Tyrosine + tyrosine hydroxylase
3.DOPA
4.Dopamine
5.NE(increased NE INHIBITS conversion of tyrosine)
6.Epi (mainly made in adrenal medulla)
2 main molecules that metabolize (break down) catecholamines, and where they’re stored:
cathechol-O-methyltransferase (COMT)
- stored in nerves
monoamine oxidase (MAO)
-stored in synapse
ACh is made by combining Acetyl CoA and choline via _
Choline Acetyl Transferase
ACh is broken down by _ into choline and acetyl CoA
cholinesterase
ANS works _ _ with renin, cortisol, and other hormones
in concertq
T/F SNS demonstrates both acute and chronic adaptation to stress pre and post synaptically
true
Presynaptic _ receptors play a large role in regulating sympathetic release
alpha
When you see vagus nerve, think _ nervous system
MUSCARINIC/ PARAsympathetic (rest, digest, etc)
-atropine blocks this! (increases HR, eyes dilate, etc) ATROPINE IS ANTICHOLINERGIC/ PARASYMPATHOLYTIC
If a drugs is a PREsynaptic alpha agonist, it is sympatho_
LYTIC
-works on alpha 2 receptors pre-synaptically to DECREASE release of NE, decreasing SNS effects
-DECREASES catecholamines
If a drug is a POSTsynaptic alpha agonist, it is sympatho_
MIMETIC
-works on adrenergic receptors post-synaptically to increase SNS effects
-increases catecholamines
2 ways to dilate the pupil:
sympathomimetic (alpha1 agonist)
OR
parasympatholytic (anticholinergic drug: ATROPINE)
-if using atropine, will block pupil constriction AND near vision accommodation (CYCLOPLEGIA)
-THINK EYEDROPS FOR DILATION
SNS effects in heart:
increase everything!
-VIA beta1
-PNS decreases everything (SA and AV node, purkinje, atria and ventricle)
SNS increases in Alpha1 + Beta2 cause a _ effect in blood vessels.
shunting
-vasoconstricts and vasodilates in different parts to move blood to vital organs
When you see alpha receptors, think:
VASOCONSTRICTION
When you see beta 2 receptors, think:
VASODILATION
-think of vessels!
When you see beta1 receptors, think:
CONTRACTILITY/ HR
HEART ONLY!! (well, besides kidneys)
T/F PNS has a massive effect on blood vessels
FALSE! Actually it is mainly just the SNS
SNS effect on lungs:
bronchoDILATION -beta2
PNS effect on lungs:
bronchoCONSTRICTION
SNS effect on GI tract:
relaxes GI system= SPHINCTERS CONTRACTED(a)
-decrease GI motility!
-full stomach!
SCARED SHITLESS
PNS effect on GI tract:
stimulates = SPHINCTERS RELAXED
-increased motility
SNS effects on kidneys:
increased renin secretion via beta1
- other non heart location = adipocytes
PNS effects on kidneys:
-
SNS effect on GU system:
relaxes bladder(b), CONTRACTS SPHINCTER(a) = NO PEE
-alpha1 contracts PREGNANT pt uterus
-beta2 has tocolytic effect on uterus (relaxed)
-liver increases BG(a + b)
PNS effects on GU system:
contracts bladder, relaxes sphincter = MORE PEE
- no effects on liver and uterus
SNS effects on pancreas:
decreases insulin secretion (a)
increases insulin secretion (b)
-tries to increase BG
lipolysis (a, b1,2,3)
Phenylephrine is a pure _ agonist:
alpha
-hella increased SBP
-hella increased DBP
-HR - reflex brady
-hella increased SVR
NE is moreso _ than _ agonist.
alpha>beta
- hella increased SBP
-kinda increased DBP
-slight increase Hr
-hella increase SVR
Epi is moreso _ than _ agonist
beta>alpha
-increased SBP
-DECREASED DBP
-hella increased HR
-DECREASED SVR (at low doses-beta1)
Dobutamine is a pure _ agonist
beta
-increase SBP
-hella decreased DBP (vasodilatory)
-hella increased HR
-hella decreased SVR
Dopamine works on dopamine, alpha, and beta receptors to:
-kinda increase SBP
-decrease DBP
-kinda increase HR
-decrease SVR (slight increase in high doses)
ANS Mechanisms
-Interference of NT synthesis (less NT made)
sympatholytic
-choline acetyl transferase inhibitors
-alpha-methyl tyrosine (inhibits tyrosine conversion)
ANS mechanisms
-Metabolic transformation by same pathway as precursor of NT (imposter-attaching to alpha2 presynaptic R)
sympatholytic
-Methyldopa
ANS mechanisms
-Blockade of transport system at nerve terminal membrane (BLOCKS reuptake)
sympathomimetic
-Cocaine
ANS mechanisms
-Blockade of transport system of storage vesicle(no protective vesicle, MOA eats NT)
sympatholytic
-Reserpine
ANS Mechanism
-Promotion of exocytosis or displacement of NT from axon terminal (turbo boost)
sympathomimetic
-Amphetamine, tyramine, ephedra, ketamine
ANS Mechanism
-Prevention of release of NT
sympatholytic
-botox, clonidine, precedex (sits on alpha 2 subunitR telling neuron it has enough NT in NMJ)
ANS Mechanisms
-Mimicry of NT at postjunctional sites (artificial NT) this one is big
sympathomimetic
-nicotine, phenylephrine, dobutamine, albuterol, terbutaline, isoproterenol
ANS Mechanisms
-Blockade of postsynaptic receptor this one is big
Sympatholytic
-atropine, atracurium, terazosin, propranolol, metoprolol, atenolol
ANS Mechanism
-Inhibition of enzyme break down of NTthis ones different
PARAsympathoMIMETIC
-ACEi, MAOi, COMT inhibitors, edrophonium, neostigmine!
ANS Mechanism
-Interference of 2nd messenger(prolongs action by preventing 2nd messenger breakdown)
sympathomimetic
-PDE 3 inhibitors (Milrinone)
Atropine poisoning mnemonic
RED as a beet,
BLIND as a bat,
DRY as a bone,
MAD as a hatter,
HOT as a hare
-often seen in ER from OTC anticholinergic OD
Analeptic is basically:
opposite of what neuroleptic anesthesia drugs do
-confident, anorexic, increased speech/motor function, decreased fatigue, alert
Alpha 1 POST synaptic R
vasoconstriction
mydriasis
relax GI
contract GI sphincters
Alpha 2 PRE synaptic R
inhibits NE release (precedex, clonidine)
Alpha 2 POST synaptic R
platelet aggregation
hyperpolarize CNS cells
Beta 1 POST synaptic R
increase conduction velocity
increase automaticity
increase contractility
Beta 2 POST synaptic R
vasodilation
bronchodilation
GI relax
Uterine relax
Bladder relax
glycogenesis
lipolysis
Dopamine 1 POST synaptic R
vasodilation -renal artery
Dopamine 2 PRE synaptic R
inhibits NE release
Which anticholinergic drug causes the most sedation?
Scop>Atropine>Glyco
glyco=0
Which anticholinergic drug causes the most antisiagogue effect?
Scop>Glyco>Atropine
Which anticholinergic increases HR the most>
Artopine>Glyco>Scop
Which anticholinergic has equal benefits of increased HR, relaxing smooth musc, and antisiagogue
Glyco
Which anticholinergic has the most mydriasiscycloplegia?
Scop>Atropine> Glyco=0
Which anticholinergic has the most PONV prevention
scop>atropine
glyco-0
T/F Anticholingergics increase H ion release into stomach
false, decrease
Stim of PRE synaptic Alpha2R =
decreased NE release
Stim of PRE synaptic Beta2R=
increased NE release
Blockade of PRE synaptic Alpha2R=
increased NE release
Blockade of PRE synaptic Beta2R=
decreased NE release