Term
| What is the only LA that lacks a base N? |
|
Definition
|
|
Term
| True/False: LA are tertiary amine bases (proton acceptors)? |
|
Definition
|
|
Term
| How is a tertiary ammonium ion charged? |
|
Definition
|
|
Term
| Due to Benzocaine's LACK of a basic N, how does it work? |
|
Definition
| entirely by membrane expansion |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| True/False: esters and amides are intermediate bonds? |
|
Definition
|
|
Term
| Name the three types of AMINES? |
|
Definition
| primary, secondary, and tertiary |
|
|
Term
What are the 5 ester LAs?
"Can Big Codes Take Patients" |
|
Definition
1) cocaine
2) benzocaine (americaine)
3) Chloroprocaine (Nesacaine)
4) tetricaine (pontocaine)
5) procaine (novocaine)
"Can Big Codes Take Patients" |
|
|
Term
| Are amides AND ester linkages clinically useful? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is another name for an aromatic ring? |
|
Definition
|
|
Term
| What are the characteristics of a aromamatic (benzene) ring? |
|
Definition
| lipophilic, increasing mebrane absorption and penetration of lipid membrane of the nerve |
|
|
Term
|
Definition
|
|
Term
| What are the subtle changes that can greatly affect potency? |
|
Definition
1) halided to aromatic ring
2) ester-like procaine to procainamide
3) larger alkyl groups on tertiary amide N produce congeners or increased lipophilicty, potency, protein binding , toxicity, and duration
|
|
|
Term
| At what pH is a tertiary amine protonated (ionic) to create hydrophilic characteristics? |
|
Definition
|
|
Term
| What are weak bases with tertiary amines as proton acceptors? |
|
Definition
|
|
Term
| At what pH is Lidocaine 65% protonated? |
|
Definition
|
|
Term
| What increases AND decreases with the base/ion ratio? |
|
Definition
Increase of pH: surroundings
Decrease pH: surroundings (base trapped in acidic environment)
Example: Fentanyl trapped into acidic tissues of the stomach |
|
|
Term
| How is thipental (acid) reversed? |
|
Definition
| with ionization at high alkaline pH |
|
|
Term
| In regard to their physical and biological properties, how does Mepivacaine relate to tetracaine? |
|
Definition
| Mepivacaine is of lower potency, hydrophobicity, and pKa |
|
|
Term
| Name the six high potency and greatly hydrophobic LAs and what is there relative conduction-blocking potency? |
|
Definition
Tetracaine, Bupivacaine, Etidocaine, Ropivacaine, Levobupivicaine, and Dibucaine
relative conduction-blocking potency = 8 |
|
|
Term
| What are the three intermediate potent LAs? |
|
Definition
| Mepivacaine, Prilocaine, Chloroprocaine, and Lidocaine |
|
|
Term
What are the six LA amides?
"Locals Do Make Patients Basically Right" |
|
Definition
1) Lidocaine (xylocaine)
2) Dibucaine (Nurpercaine)
3) Mepivacaine (carbocaine)
4) Prilocaine (citanest)
5) Bupivacaine (marcaine)
6) Ropivacaine (naropin)
"Locals Do Make Patients Basically Right" |
|
|
Term
| What is the purpose of longer alkyl additions? |
|
Definition
Increased lipophilicity, potency, duration, toxicity and protein binding.
Increased potency required fewer ions.
Delayed onset = increased latency time |
|
|
Term
|
Definition
| increased protein receptor binding and plasma protein binging (reservoir) |
|
|
Term
Amide or Ester?
lidociane to hydrophobic congener etidocaine |
|
Definition
|
|
Term
Amide or Ester?
mepivacaine to hydrophobic congeners bupivacaine and ropivacaine |
|
Definition
|
|
Term
Amide or Ester?
procaine to hydrophobic congener tetracaine |
|
Definition
|
|
Term
| What lacks butyrylcholinesterase? |
|
Definition
|
|
Term
What is the pKa of most LA?
What dose pKa determine? |
|
Definition
a)8
b) the higher the pKa, the more protonation at a pH of 7.4 |
|
|
Term
| Weak bases will protonate at pH of________ forming > 50%______. |
|
Definition
a) 7.2-7.4
b) cations
[B+H = BH; BH = cation (positive ion)] |
|
|
Term
| True/False: Lidocaine is 25% protonated at a pH of 7.4. |
|
Definition
| False: Lidocaine is 65% protonate at a pH of 7.4 |
|
|
Term
| Membrane concentrations of B/BH are compared to what? |
|
Definition
|
|
Term
| The membrane pKa of a LA is one unit beow ______ ______ pKa. |
|
Definition
|
|
Term
| In what environment does B concnetrate? |
|
Definition
|
|
Term
| What is the purpose of membrane expansion? |
|
Definition
Membrane expansion may contribute to conduction blocking, especially for the nonionic ester benzocaine.
** Benzociane may work exclusively by membrane expansion.** |
|
|
Term
| True/False: Surrounding pH is influential due to an altering % of protonation to base ratio. |
|
Definition
|
|
Term
| What is the cause of trapping bases (LA and opioids) intracellularly? |
|
Definition
| the nerve cytoplasm's (axoplasm) acidic environment |
|
|
Term
What is the pH intracellularly?
It may be different if what enters the cell? |
|
Definition
a)pH= 7.2
b) pH may be differnet is CO2 enters the cell |
|
|
Term
| As intracellular CO2 further lowers the pH what increases? |
|
Definition
protonation (cationic) trapping in the more acidic environment
NaHCO3 = NaOH + CO2 |
|
|
Term
| Serum protein binding parallels ___(4)____ but is unrelated to _________. |
|
Definition
a) paralells: potency, toxicity, duration and lipophilicity
b) unrelated: receptor proteins mechanism of action
|
|
|
Term
| True/False: Serum proteins are GOOD models of receptor protein site of action? |
|
Definition
| False: serum protein are POOR sites of action |
|
|
Term
| According to sources protein binding is a plasma reservoir associated with _________ and delays both ______ & _________. |
|
Definition
| According to sources protein binding is a plasma reservoir associated with duration and delays both onset and clearance. |
|
|
Term
| What is the potency and conduction blocking of chloroprocaine? |
|
Definition
| low potency, low toxicity, rapid onset, high dose, high allergy group |
|
|
Term
| At what potency are ropivacaine (Naropin), levobupivacaine (Chirocaine) and dibucaine (Nuperacaine) LAs? |
|
Definition
|
|
Term
| True/False: Thecommercial preparations of LAs are BASIC, increasing the water solubility (protination)? |
|
Definition
|
|
Term
| What better preserves epi? |
|
Definition
| commercially prepared acidification |
|
|
Term
| What is the purpose of alkalinity? |
|
Definition
1) has no immedicate problem with epi oxidation
2) increases base penetration
3) CO2 from carbonation moves into cell and traps ionic form of local due to acidified cytoplasm |
|
|
Term
| True/False: Preservative should be avoided in the use of spinal LAs. |
|
Definition
|
|
Term
| What are parabins (para hydroxy benzoate)? |
|
Definition
| antibacterial but potential allergens and irritate bare nerves |
|
|
Term
| What should you do with discolored solutions and why has the discoloration occured? |
|
Definition
| Light oxidized epinephrine, discoloring it. You should "toss" is (do not use it). |
|
|
Term
| Cm (minimum) is the minimum concentration of LA that will do what? |
|
Definition
| block nerve impulse conduction |
|
|
Term
| Cm is a way of comparing ______. |
|
Definition
potency
[analogous to MAC of inhalants] |
|
|
Term
| What provides a 3-D shape to the carbon atom? |
|
Definition
| tetrahedral characteristics of its stereochemistry |
|
|
Term
|
Definition
| opposite shapes, structures are mirror images, handedness = hand-in-glove |
|
|
Term
| What LAs are examples of congeners (about the same structure)? |
|
Definition
| mepivacaine, bupivacaine and ropivacaine |
|
|
Term
| What is a single stereoisomer of racimic bupivacaine (Marcaine, Sensorcaine)? |
|
Definition
| levobupivacaine (Chirocaine) |
|
|
Term
| The metabolite structure of benzocaine is very similar to the allergen ______. |
|
Definition
| para amino benzoic acid (PABA) |
|
|
Term
| What is a common preservative? |
|
Definition
| para hydroxy benzoic acid, methyl paraben |
|
|
Term
| How is the internal receptor on the Na channel for LA mainly acessed? |
|
Definition
|
|
Term
|
Definition
| less drug, more lipid soluble and more protein binding |
|
|
Term
| What is the approximate pKa of LA? |
|
Definition
|
|
Term
| LA bind to Na channel receptors best when the channels are in a (open/inacitve) OR (closed/active) state. |
|
Definition
| LA bind to Na channel receptors best when the channels are in the open/inactive state. |
|
|
Term
| Procainamide is ____ excreted and very little ______. Some_____ _____ takes place. |
|
Definition
Procainamide is renal excreted and very little hydrolysis.
Some liver conjugation. |
|
|
Term
| LA work on ______ gated sodium channels and muscle relaxants work on _____ gated sodium channels |
|
Definition
LA: voltage gated Na channels
MR: ligand gated Na channels |
|
|
Term
| LA and muscle relaxants both prevent membranes from reaching _________. |
|
Definition
| transmembrane threshold potential |
|
|
Term
| What is the Epinephrine concentration and test dose for LA use? |
|
Definition
Epinephrine 1:200,000=5mcg/cc
Test Dose 3cc=15mcg |
|
|
Term
| What is the max dose for Epinephrine for LA use? |
|
Definition
|
|
Term
| True/False: Fresh Epi is best for use in LA? |
|
Definition
|
|
Term
| What is the pH of a fresh Epi vial? |
|
Definition
|
|
Term
| What is a "caution" when using Epi with a beta blocked or eldery patient? |
|
Definition
|
|
Term
| What is the regional, Lidocaine dose for an upper extremity? |
|
Definition
|
|
Term
| What is the concentration for regional Lidocaine? |
|
Definition
2%= 2gm/100cc
2% = 20mg/cc |
|
|
Term
| What is the dose and concentration of regional Lidocaine for an ARM? |
|
Definition
250mg with NS to 50cc
5mg/cc = 0.5% |
|
|
Term
| What is the concentration and dose of regional Lidocaine for a LEG? |
|
Definition
250mg to 100 ml = 0.25%
2.5mg/cc = 0.25%
(extra volume for leg aids spread) |
|
|
Term
| At what landmark on a leg would be a concern for tourniquet placement? |
|
Definition
| Tourniquet on a superficial peroneal nerve (lateral tibial) is a concern. |
|
|
Term
| What LA is of concern for cardiovascular collapse (stone heart)? |
|
Definition
|
|
Term
| List LA plasma levels in order of highest to lowest for anatomic injection site. |
|
Definition
| Highest with intercostal, caudal, epidural, brachial plexus and lest with SQ. |
|
|
Term
| At what concentration would Epi be 2mcg/ml? |
|
Definition
|
|
Term
|
Definition
| Epi 1:1= 1gm/1cc OR 1kg/1L |
|
|
Term
|
Definition
|
|
Term
| 0.2mg Epi 1:1,000 = _____. |
|
Definition
| 0.2 cc Epi 1:1,000 = 200mcg |
|
|
Term
| If you use 7mg/kg Lidocaine, what is the max dose of a solution containing Epi? |
|
Definition
|
|
Term
| All LA are ____ _____ bases (proton acceptors). |
|
Definition
|
|
Term
| What is the charged ionic form of a tertiary amine base? |
|
Definition
|
|
Term
| What do schwann cells surround all nerves to produce what? |
|
Definition
| myeline covering large nerves |
|
|
Term
| Where is schwann cell produced myeline found? |
|
Definition
| on large A and B nerve fibers |
|
|
Term
| Where is schwann cell produced myeline found? |
|
Definition
| on large A and B nerve fibers |
|
|
Term
| Where is schwann cell produced myeline found? |
|
Definition
| on large A and B nerve fibers |
|
|
Term
|
Definition
| nodes of ranvier increased rate of conduction |
|
|
Term
| What type of Schwann cell sheath is on C fibers and nerves at the NMJ? |
|
Definition
|
|
Term
| Describe the antaomy of a nerve. |
|
Definition
| A nerve is made up of fascicles which are groups or bundles of nerve axons |
|
|
Term
| Describe epineurium, perineurium and endoneurium. |
|
Definition
Epineurium convers a nerve
Perineurium covers a fascicle
Endoneurium covers a nerve axon. |
|
|
Term
| Describe the electrolyte composition of a cell's interior cytoplasm. |
|
Definition
| cell interior cytoplasm is righ in K and poor in Na and Cl. this is reverse of sea water and plasma |
|
|
Term
|
Definition
| structure of ansonal membrane: biologic molecular lipid bilayer of amphiphilic (lipo and hydro) phospholipids |
|
|
Term
| What is a "fluid mosaic"? |
|
Definition
| zwitterions contain positive and negative |
|
|
Term
| Where is the site of action for LA? |
|
Definition
| Na channels concentrated at nodes of Ranvier |
|
|
Term
|
Definition
| explains unidirectional propagation |
|
|
Term
|
Definition
| myelinated, large, fast, motor function |
|
|
Term
|
Definition
| myelinated, large, fast, tactile and proprioception function |
|
|
Term
|
Definition
| myelinated, intermediate diameter, intermediate speed, muscle tone function, highly susceptible to LA block |
|
|
Term
|
Definition
| nyelinated, small diameter, slow; pain, cold temperature and touch function; more likely to be blocked by LA |
|
|
Term
|
Definition
|
|
Term
| There are three Na channel states. What are they? |
|
Definition
Closed/Resting
Open/activated
inactivated/transition |
|
|
Term
| Describe the difference between the outer and inner gates. |
|
Definition
Outer: voltage dependent
Inner: time dependent |
|
|
Term
| True/False: K channels precede Na channels in both opening and closing? |
|
Definition
| FALSE: Na channels precede K channels in both opening and closing |
|
|
Term
| What happens when a channel is resting (closed)? |
|
Definition
| activation gate (voltage) is closed and inactivation gate (time) is open. thus, no ion flow. |
|
|
Term
| What happens with activation of a gate? |
|
Definition
| activation (charge) abruptly allows Na influx by opening outer gate until inactivation gate (time) slowly closes for a while. |
|
|
Term
| What does it mean for a gate to be inactivated? |
|
Definition
| a transition phase between activated (open) and resting (closed) Na channels |
|
|
Term
| True/False: Being refractory to a membrane's voltage changes = unresponsive? |
|
Definition
|
|
Term
| When a membrane is unresponsive what happens to the inner time-dependent gate? |
|
Definition
|
|
Term
| What is explained by positive feedback on resting adjacent voltage gates? |
|
Definition
| propagation and inactivation due to time gate |
|
|
Term
| True/False: Time gate explains unidirectional? |
|
Definition
|
|
Term
| True/False: LA both prolong inactivated states and bind to open or about to open channels more than LA bind to resting state? |
|
Definition
|
|
Term
| What are three descriptors of LAs? |
|
Definition
use-dependent
frequency-dependent
phasic block |
|
|
Term
| How do LA bind to voltage gate receptors? |
|
Definition
| from inside cytoplasm or the membrane |
|
|
Term
| True/False: Once any of the three states of receptors are bound by a LA, it is active? |
|
Definition
|
|
Term
| What do LA not do to the channel from plasma or cytoplasm? |
|
Definition
| they do not "plug" the channel |
|
|
Term
| What plugs external opening and is a toxin? |
|
Definition
|
|
Term
| Why can Na only fit through Na channels? |
|
Definition
| Na holds 5 waters and is too big for the smaller K channel. K is too big for waterless Na ions. na is stripped of water when passing through Na channels. SO...Na and K rates are ion specific. |
|
|
Term
| Describe the characteristics of MODERATELY hydrophobic LA solutions. |
|
Definition
| act fastest due to lower potency, so they are able to be delivered in higher concentrations |
|
|
Term
| Describe the characteristics of HIGHLY lipophilic LA solutions. |
|
Definition
| very potent but low concentration, so they have a slow onset |
|
|
Term
| At what pH are LA botted as hydrochloride salts and how does the environment contribute to the LA? |
|
Definition
| LA are bottled as hydrochloride salts at a pH of 6.0, thus they are ionic and more water soluble. |
|
|
Term
| What does a base add to LA and epinephrine (1:200,000)? |
|
Definition
|
|
Term
| What is a function of pH and pKa? |
|
Definition
|
|
Term
| Why if Fentanyl trapped in the stomach? |
|
Definition
| low pH favors ions for bases |
|
|
Term
| True/False: potent drugs are used at low concentrations, thus clow onset (long latency) even with high lipophilicity? |
|
Definition
|
|
Term
| True/False: Hydrophilicity parallels potency, toxicity, protein binding, and duration? |
|
Definition
|
|
Term
| What favors onset: acidity or alkalization? |
|
Definition
|
|
Term
| What hinders onset, but favors trapping? |
|
Definition
|
|
Term
| What enters the cell, lowering the intracellular pH? |
|
Definition
|
|
Term
| What increases plasma pH for better membrane potential? |
|
Definition
|
|
Term
| An increase or decrease in plasma pH favors what? |
|
Definition
| rapid onset and long duration of LA |
|
|
Term
| When can bases be trapped in an acidic environment? |
|
Definition
| nerve axoplasma, fetus, brain and stomach |
|
|
Term
| TRUE/FALSE: LA Do change resting membrane potentials and/or thresholds? |
|
Definition
| FALSE: LA DO NOT change the potentials or thresholds |
|
|
Term
| How do LA affect NA channels? |
|
Definition
| LA slow and decrease the degree of depolarization at Na channels and eventually the membrane cannot reach threshold. |
|
|
Term
| What is the effect of repolarization? |
|
Definition
| repolarization overshoots threshold so the potential is further below resting potential (partially refractory). |
|
|
Term
| How do electrolyte imbalances influence a membrane potential? |
|
Definition
| Lyte imbalances influence the resting membrane potential threshold and action potential. low Na lowers action potential, low Ca and high Mg lowers threshold, low K lowers resting membrane. |
|
|
Term
| When channels do not open due to LA, what happens to Na, K, and Ca currents? |
|
Definition
|
|
Term
| What effect do toxins have on chnnels? |
|
Definition
| they may externally occlude or destroy channels |
|
|
Term
| How does membrane expansion effect a membrane? |
|
Definition
| it may play a minor role based on lipophilicity |
|
|
Term
| True/False: LA block open (active) more than transition (inactive) and much more than closed (resting)? |
|
Definition
|
|
Term
| True/False: LA bind inactive sites quicker and longer? |
|
Definition
|
|
Term
| What three factors enhance block on repetitively stimulated nerves? |
|
Definition
frequency-dependent
use-dependent
phasic inhibition |
|
|
Term
| With a differential block is sensory or motor blocked first? |
|
Definition
|
|
Term
| What two LA have equal or greater motor to sensory? |
|
Definition
| marcaine 0.75% or etidocaine (surgery) |
|
|
Term
| Which two LA are more sensory than motor? |
|
Definition
| ropivacaine and bupivacaine 0.25% or 0.5% (OB) |
|
|
Term
| True/False: Chronic pain is hard to block with low doses? |
|
Definition
| FALSE: low doses (bupivicaine in the pain clinic) |
|
|
Term
| Frue/False: It is certain that bupivicaine stone heart is due to prolonged concentration in active cardiac muscle or nerve. |
|
Definition
|
|
Term
| _________ gets the drug to the receptor and ________ (charge) keeps it there. |
|
Definition
hydrophobicility = receptor
hydrophilicity= keeps it there |
|
|
Term
| Dissociation of LA from receptors depends on 4 factors affecting the charge that keeps it there. What are the four factors? |
|
Definition
structure
pKa
pH
hydrophobicity |
|
|
Term
| What is in parallel to duration? |
|
Definition
lipophilicity
protein receptor affinity
potency |
|
|
Term
| What two lytes stabilize the outer cell membrane? |
|
Definition
|
|
Term
| If Ca stabilized the excitatory threshold what dose low Ca do? |
|
Definition
| low Ca narrows resting membrane potential to threshold (like spontaneous firing following a parathyroidectomy) |
|
|
Term
| What raises the seizure threshould? |
|
Definition
| increased Mg (OB an pheocromocytoma) |
|
|
Term
| True/False: Ca interferes with Mg on muscle contration, lowing vascular and uterine tone. |
|
Definition
| FALSE: Mg interferes with Ca |
|
|
Term
| What effect does Mg have on NMJ? |
|
Definition
| Mg decreases ACh presynaptic release at NMJ while Ca increases this ACh release. |
|
|
Term
| What lyte determines the resting membrane potential? |
|
Definition
|
|
Term
| What channels are voltage-dependent? |
|
Definition
|
|
Term
| What channels are always voltage independent? |
|
Definition
| ligand gated channels (GABA and ACh) |
|
|
Term
| ______ of _______ is rapid as exposure to "the" plasma cholinesterase. |
|
Definition
|
|
Term
| True/False: Chloroprocaine in OR is slow and tetracaine in spinals is short? |
|
Definition
FALSE: chloroprocaine = short
tetracaine = slowW2~S2 |
|
|
Term
| Because CSF has not butyrylcholineresterase, the rational in the use of __________ (novocaine) for intermediate spinal duration. |
|
Definition
|
|
Term
| Esters may yeild this potential allergen. |
|
Definition
| PABA: para-amino benzoic acid |
|
|
Term
| What ester undergoes significant metabolization in the liver as well as ester hydrolysis? |
|
Definition
|
|
Term
| True/False: amides are metabolized in teh liver and are less stable in solution? |
|
Definition
|
|
Term
| Potency is primarly from lipophilicy or hydrophilicity? |
|
Definition
|
|
Term
| High potency = _______ dose. |
|
Definition
| low dose (low # of molecules |
|
|
Term
| What effect does Epinephrine have on a block? |
|
Definition
| Epinephrine increase the desity of the block (increases potency) by reducing wash-out by blood flow due to vasodilation, as significant effect by many LA. Epi keeps LA at site longer, increasing duration. |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| TRUE/FALSE: potent drugs are of high concentration, rapid onset/short latency? |
|
Definition
| FALSE: low concentration, slow onset, prolonged latency |
|
|
Term
| What determines toxicity? |
|
Definition
|
|
Term
| ________ affect on B/B+ shortens onset. |
|
Definition
|
|
Term
| True/False: protein binding effects duration? |
|
Definition
|
|
Term
| Plasma proteins are reservoirs for LA and thus decrease availability of LA for what 3 things? |
|
Definition
1)block
2) metabolism
3) removal from site of action |
|
|
Term
| ________ are proteins with druation affected by binding. |
|
Definition
|
|
Term
| LA have initial vaso- (constriction/dilation) followed by (constriction/dilation)? |
|
Definition
| LA have initial vasoconstriction followed by dilation. this is a biphasic property. |
|
|
Term
| what two LA are vasoconstrictors. |
|
Definition
| cocaine and maybe ropivacaine (stereospecific) |
|
|
Term
| What affect does Epi have on the constriction of LA? |
|
Definition
| maintains the initial vasoconstriction, slowing redistribution and prolonging duration |
|
|
Term
| What LAs are mostly association with dose dependent differential block? |
|
Definition
| Bupivicaine and ropivacaine, since epidural in OB preserves abdominal muscles for pushing |
|
|
Term
| Low or high concentrations of LA seem to produce differential blocks better? |
|
Definition
| low concentrations, like bupivacaine |
|
|
Term
| True/False: the theory of differential blocks is poorly understood. |
|
Definition
|
|
Term
| _____, ______, and _______ effect onset, effectiveness, spread and duration of LAs. |
|
Definition
| dosage, concentration, volume |
|
|
Term
| How many nodes on myelinated nere fibers must LA block and what fibers are they |
|
Definition
| LA need to block 3 or more nodes of the large A and/or B fibers |
|
|
Term
| What may increase bupivacaine's toxicity? |
|
Definition
|
|
Term
| While decreasing blood flow, washout is probably also influenced by what three things? |
|
Definition
1) fat storage
2) receptor binding
3) plasma protein binding |
|
|
Term
| Site of injection: ______ has the slowest onset and longest duration with motor and proximal blocks before sensory and distal blocks due to exposure. |
|
Definition
| Brachial plexus (lots of membranes to penetrate and low vascularity) |
|
|
Term
| A brachial plexus block has proximal and motor toward mantal so _____ and _____ is slowest in onset. |
|
Definition
| so core distal and sensory is slowest in onset |
|
|
Term
| Spinals (no myeling and low dose) have ____ onset and ____ duration. |
|
Definition
| rapid onset and short duration |
|
|
Term
| these fibers are blocked before/above sensory A-delta nd C fibers. |
|
Definition
|
|
Term
| A-delta and C fibers are blocked before/above these fibers at two-segment regression. |
|
Definition
|
|
Term
| This is blocked before CNS vagus. |
|
Definition
| peripheral SNS blocked before CNS vagus |
|
|
Term
| What enhances penetration? |
|
Definition
| carbonation (increases B) |
|
|
Term
|
Definition
| CO2 diffusion into axoplasma (decreased pH) |
|
|
Term
|
Definition
|
|
Term
| Alkalization is best for both of these two characteristics. |
|
Definition
| fast onset and long duration |
|
|
Term
| Mixtures can combine rapid onset LA with ____ _____ LA. |
|
Definition
|
|
Term
| True/False: LA do not potentiate or nullify each other? |
|
Definition
|
|
Term
| What three LA are combined for spinal? |
|
Definition
| procaine (novocaine) + tetracaine (pontocaine) or lidocaine + dupivacaine |
|
|
Term
| what two LA are combined for OB? |
|
Definition
| chloroprocaine (nesacaine) + bupivacaine |
|
|
Term
| What LA produce a relatively long spinal block due to low plasma cholinesterases in CSF? |
|
Definition
| prociane (novocaine) and other esters |
|
|
Term
| What medical condition can change protein binding? |
|
Definition
|
|
Term
| True/False: low protein binding decrease placental transfer? |
|
Definition
| FALSE: high protein binding |
|
|
Term
| True/False: Esters are metabolized before they can reach the fetus? |
|
Definition
|
|
Term
| What physiological change effects a block in pregnancy? |
|
Definition
| smaller spinal/epidural space |
|
|
Term
| What LA is highly ionic, slwoing the spread to a fetus? |
|
Definition
|
|
Term
| Tetracaine is highly water soluble at low pH of___. |
|
Definition
|
|
Term
| Why is tetracaine not used in brachial plexus blocks, but is okay for spinals (exposed nerves)? |
|
Definition
| only 14% is nonionic at pH 7.4 so giving it poor penetration |
|
|
Term
| What is the pH of topical EMLA cream (lidocaine/prilocaine)? |
|
Definition
|
|
Term
| How many minutes does it take for EMLA cream to be equal to IV effect and for a deep effect? |
|
Definition
| 30 minutes for IV and 2 hours for deep effect |
|
|
Term
| What is the greatest risk for newborns and infants when using EMLA cream? |
|
Definition
| prilociane toxicity (methemoglobin: metabolite replaces oxygen on Hgb) |
|
|
Term
| what topical anesthetic is used for intubation, oral, burns, or hemorrhoids that may produce stystemic toxicity? |
|
Definition
| topical benzocaine (ceticaine) or lidocaine |
|
|
Term
| What two LAs can be used in all regional blocks, making them popular? |
|
Definition
| bupivacaine and lidocaine |
|
|
Term
| What LA is especially prolonged by Epi? |
|
Definition
|
|
Term
| True/False: injection pain of LA is due to the low pH of epinephrine? |
|
Definition
|
|
Term
| What are the doseages in mg for potent, intermediate, and low potency LA? |
|
Definition
potent: 200mg
intermediate: 500mg
low: 1000mg |
|
|
Term
| By adding epi to LAs you can use how much more drug without systemic effects and increase duration by 50%. |
|
Definition
|
|
Term
| What drug (without epi) have a maximum of 150-200 mg? |
|
Definition
|
|
Term
| Peripheral nerve blocks are minor, so how many nerves do they block? |
|
Definition
|
|
Term
| How do you select a LA for a PNB? |
|
Definition
| all locals have fast onset so select LA for its duration |
|
|
Term
| Can you use Epi in PNB to prolong the sensory and motor of the block? |
|
Definition
|
|
Term
| What kind of post-sugical pain can by controlled well by intrapleural, intercostal, or epidural blocks due to their high systemic uptake? |
|
Definition
| abdominal/thoracic post-surgical pain |
|
|
Term
| What is the most common major PNB? |
|
Definition
|
|
Term
| TRUE/FALSE: PNB are used for long lasting anesthesia? |
|
Definition
|
|
Term
| In what order dose a PNB set in? |
|
Definition
| motor > sensory > SNS depending on the axon location in mantle more than serve size or myelination |
|
|
Term
| In what order do central blocks set in? |
|
Definition
|
|
Term
| Central Neural Blockade order of block and location of dermatone. |
|
Definition
| SNS 2 dermatones above sensory which is 2 dermatones above motor |
|
|
Term
| What are the characteristics of intermediate LA, Lidociane and procaine when used for a CNB with Epi? |
|
Definition
| Lidocaine and Procaine last 1-2 hours with Epi prolonging its duration by 50% |
|
|
Term
| How long do long-lasting LA work when used with Epi? |
|
Definition
|
|
Term
| The motor block of bupivacaine depends on the percentage used. What percentages can be used? |
|
Definition
|
|
Term
| The concentration of a LA affects what? |
|
Definition
| dose, volume, differential block and spread |
|
|
Term
| How do you mix tetracaine for a CNB and how long is its duration ? |
|
Definition
| spinal tetracaine 1cc 1%(10mg) diluted to 0.5% mixed with 1cc 10% glucose = 2 cc total for a 3-4 hour hyperberic spinal. |
|
|
Term
| how is lidocaine mixed for a CNB and how long does it last? |
|
Definition
| 100 mg Lido (2cc 5%) premixed with glucose 7.5% gives a 45-60 minute block |
|
|
Term
| What LA can be mixed well with tetracaine 1% (10mg) to speed its slow onset. |
|
Definition
| prociane 1cc 10% (100mg) + tetracaine 1cc 1% (10mg) |
|
|
Term
| Because tetracaine exhibits poor membrane crossing and low CSF butyrylcholinesterase it is chosen for what blocks? |
|
Definition
| it is good for spinals but poor for epidural and brachial plexus blocks |
|
|
Term
| True/False: tetracaine resembles intrathecal MS since both are highly nonionic? |
|
Definition
|
|
Term
| What type of LAs do hypobaric spinal require? |
|
Definition
| preservative free water for 4-5 cc total volume |
|
|
Term
| What pharmacokinetic characteristic is affected by patient status? |
|
Definition
| biotransformation and excretion |
|
|
Term
| What age group have prolonged duration of LA in plasma which probably reflects decreased liver metabolism of amides? |
|
Definition
extreme ages
(lower butyrylcholinesterase in older males) |
|
|
Term
| Describe the signs of Lidocaine toxicity in order of occurance. |
|
Definition
1) lightheadedness, tinnitus, circumoral and tongue numbness
2) visual disturbances
3) musclular twitching
4) convulsions
5) unconciousness
6) coma
7) respiratiory arrest
8) CVS depression
9) CVS collapse |
|
|
Term
| What changes make a patient more sensitive to seizures? |
|
Definition
| elevated CO2 and acidosis lowers the seizure threshold and increases LA trapping in brain cells |
|
|
Term
| What affect dose acidosis play on the body? |
|
Definition
| acidosis increases CBF and decrease protein binging for more free drug availability to the CNS |
|
|
Term
| True/False: cardiac fast Na channel block will slow depolarization? |
|
Definition
|
|
Term
| What channel block may decrease contractility? |
|
Definition
|
|
Term
| True/False: Toxicity parallels potency? |
|
Definition
|
|
Term
| What drug is very arrhythmic? |
|
Definition
| Bupivacaine (goes in fast if a high concentration is used and has prolonged duration) |
|
|
Term
| What is the max concentration of bupivicaine that is allowable in OB patients? |
|
Definition
|
|
Term
| What condition may be precipitated by bupivacaine? |
|
Definition
|
|
Term
| What are two better LA choices over Bupivacaine? |
|
Definition
| levobupivacaine (chirocaine) or ropivacaine (naropin) |
|
|
Term
| What possible factors makes Ropivacaine a better coice than bupivacaine in OB? |
|
Definition
1) vasoconstriction
2) slighlty shorter duration
3) more differential
4) have less placenta transfer
5) less cardiac toxicity |
|
|
Term
| What three things potentiate negative inotropic and chronotropic action and increase arrhythmias, enhancing toxicity of bupivacaine? |
|
Definition
| hypercarbia, hypoxia, and acidosis |
|
|
Term
| What LA can cause methemoglobinemia and how can this be minimized? |
|
Definition
| using Prilocaine (Citanest) at a max dose of 500 mg |
|
|
Term
| Oxygen and prilocaine metabolite are _____ agents. |
|
Definition
| oxidizing agents (bind heoglobin) |
|
|
Term
| what can be administered to reverse methemoglobinemia? |
|
Definition
| reducing agent methylene blue 100 mg |
|
|
Term
| PABA is an allergen. what other LA have structure similarities? |
|
Definition
| procaine (novocaine) and benzocaine metabolite and methylparabin (Na methyl para-hydroxybenzoate: salt preservative) |
|
|
Term
| True/False: allergies due to LA amides are most common? |
|
Definition
|
|
Term
| What two things make LA cytotoxic in spinal, epidural or in TIVA? |
|
Definition
| preservatives and high doses |
|
|
Term
| What is cauda equina syndrome? |
|
Definition
| dense concentration of LA on non-myelinated nerves |
|
|
Term
| What LA has most recently been a suspect of spinal toxicity, even besides micro catheters? |
|
Definition
|
|
Term
| What is the current name for transient radicular neuropathy (TRN)? |
|
Definition
| Transient Radicular Irritation (TRI) or Transient Radicular neurologic symptoms (TNS) |
|
|
Term
| What are some reasons for symptoms (radicular [butt] pain, back pain, hypothesia, parasthesia) resembling TRI? |
|
Definition
| epi use, position (lithotomy), aging, stretching |
|
|
Term
| When is TRIs onset and how long does it last? |
|
Definition
| TRI usually onsets in 24 hours and is transient for a few days up to months. Direct muscle injection with LA causes only transient changes. |
|
|
Term
| What was really the cause of chloroprocaine (nesacaine) permanent toxicity? |
|
Definition
| Na bisulfate additive at low pH |
|
|
Term
| rapid metabolis, onset, and short duration makes what LA safe for labor epidural and the fetus? |
|
Definition
| chloroprocaine (now available as preservative free or with another non-toxic preservative) |
|
|
Term
| What is the teatment for seizures? |
|
Definition
1) oxygen
2) seizure control (pentothal, propofol, midazolam)
3) airway control |
|
|
Term
| When raising the seizure threshold with Benzos what may you be missing? |
|
Definition
| early warning CNS signs before cardiovascular collapse, such as with lidocaine IV regional blocks |
|
|
Term
| What drugs may be used to treat seizures that have a fast onset, short duration and are easy to titrate? |
|
Definition
| barbs (anticonvulsants), propofol, midazolam, and Succs (20-40mg): have them ready with a plan! |
|
|
Term
| What blocks catacholamine reuptake and accounts for its unique vasoconstrictive effects and probably its other stimulatory effects. |
|
Definition
| Cocaine (blocks reuptake of norepi and dopamine [pleasure transmitter]) |
|
|
Term
| Dibucaine amide inactivates __% of normal and __% atypical plasma cholinesterase |
|
Definition
|
|
Term
| The % of plasma cholinesterase that Dibucaine inactivates indicates what? |
|
Definition
| butyrylcholinesterace quality, but not quantity |
|
|
Term
| One atypical gene = __% & Two atypical genes = __% inhibition of dibucaine (1/3200 patients). |
|
Definition
One atypical gene = 50-60%
Two atypical genes = 20-30% |
|
|
Term
| List in order of concentration for equivalent depth of block the 8 most commonly used LA. (N fig 9-10) |
|
Definition
Procaine & Chloroprocaine
Mepivacaine & Prilociane
Lidocaine
Tetracaine
Bupivacaine
Etidocaine |
|
|
Term
| What is the max dose (with epi) for Chloroprocaine, Lidocaine, and Bupivicaine ? |
|
Definition
chloroprocaine: 1000mg
lidocaine: 500 mg (7mg/kg)
bupivacaine: 225 mg (175 mg plain) |
|
|
Term
| From what nerve fibers does pain originate? |
|
Definition
| myelinated A delta and unmyelinated C fibers |
|
|
Term
| What block site is known for having the highest plasma concentration and what site follows behind it |
|
Definition
| intercostal then caudal, epidural, brachial plexus |
|
|
