Exam 3 part V Flashcards
which concentration of epi would have a higher plasma concentration @ 1mL (thus increased risk of toxicity) - 1% or 2%
2% ; 2% = 20 mg/ml which is a higher DOSE than 1%. plasma concentration of LA is directly proportional to the dose
plasma concentration of lido is directly proportional to the ________________
dose
all LA anesthetics cause vasodilation –> increased absorption, decreased DOA, and increased risk of toxicity EXCEPT _____________, __________, _____________
cocaine (inhibits reuptake of NE) lidocaine ropivicaine
what is the rapid phase of the two compartment model (for LA)
highly perfused tissues (VRG) reach equilibrium quickly
what is the slow phase of the two compartment model (for LA)
equilibrium of lesser perfused tissues happens slower
which tissue group recieves the highest concentration of LA from redistribution
muscle group
order of distribution of LA throughout the body
- VRG 2. muscle group 3. fat group 4. vessel poor group
saturated, inhibited, or atypical p-AchE can _______________ the 1/2 life of __________ LA
prolong; ester
all amide LA are metabolized by the hepatic biotransformation via CYP450 except __________________, which is metabolized via _____________________
articaine; plasma cholinesterase
T/F: poorly functioning P-AchE effects DOA of ester LA
false; the absorption away from the site of action remains unchanged
Amides should be avoided in patients with ____________________
renal failure
if pt has hepatic dysfunction you should _______________ single dose and ____________ infusions of amide LA
make no adjustment; decrease by 10-50%
during pregnancy, women will have increased ______________ & __________ of the LA with spinals and epidurals
spread; depth
why do pregnant women have increased spread and depth of LA with spinals and epidurals
- decreased thoracolumbar CSF 2. increased susceptibility to LA d/t increased progesterone 3. gravid uterus = dilated epidural veins = narrowed SA and epidural space
modification to dose of LA in spinals and epidurals for pregnant women
you decrease dose
T/F: epi markers will prolong the DOA to the same extent with all LA
FALSE
purpose of epi additives to LA
- used to detect intravacular injection with PNB and epidurals 2. prolongs the intensity of the block 3. increases safety, quality, rate of onset, and reduced blood loss
epi markers in LA will have much more pronounced effects with ____________acting LA
short
how do epi markers prolong the intensity of the LA
local vasoconstriction which: 1. decreases rate of vascular absorption 2. decreases risk of toxicity 3. increases the LA available at the site
what is the typical concentration of epi with LA
1:200,000 (5 mcg/mL)
when testing an epidural catheter you are going to place _________ cc of LA + epi, and if you are in the right place, ______________ will happen
3; nothing (no raise in HR, BP, or anesthesia)
effect of vasoconstrictive additive on the LA is influenced by:
- drug (LA and vasoconstrictor) 2. dose of each 3. concentration of each 4. site of injection
what vasopressor drugs can be used as additives to LA
- epi (superior) 2. phenylephrine 3. norepinephrine
which vasoconstricting additive is the best for the nerve stimulator technique with peripheral blocks
epi
alpha2 adrenergic agonist additives to LA are most effective on ______________ & ____________ fibers
C (sensory); A-delta (motor)
MOA of adding alpha 2 agonist to LA
- effect spinal and supraspinal receptors 2. interrput the nerves ability to achieve resting membrane potential from the inactive state
alpha-2 agonists are added to LA for what type of blocks
- caudal (peds) 2. neuraxial 3. PNB
s/e of adding clonidine to LA block
- hypotension 2. bradycardia 3. sedation
______________ mcg of clonidine added to LA will increase analgesic effect by about _______________ minutes
100; 100
“updosing an epidural” means that you are adding _________________ to the LA
sodium bicarbonate
sodium bicarb is widely used as an additive to LA in ________________ anesthesia
epidural
effects of adding sodium bicarb to LA in epidural
- increases the pH of the solution –> increased non-ionized form of LA 2. with injection more LA crosses the membrane –> increased speed of onset 3. also decreases pain and stinging
if adding sodium bicarb to LA you should beware of NaHCO3 ability to __________________
precipitate
effect of adding hyaluronidase to LA
increases the spread of LA via facilitating diffusion into the nerve
MOA of hyaluronidase
enzyme that hydrolysis hyaluronic acid (which inhibits the spread of substances through tissues)
hyaluronidase as an additive to LA is commonly seen with _______________ procedures
opthalamic
potential adverse effects of hyaluronidase into LA
- allergic response 2. shorten DOA 3. increased risk of toxicity
what types of blocks can ketamine be added to
- spinals (intrathecal) 2. epidural 3. PNB
what is the effect of adding ketamine to LA for an intrathecal (spinal) injection
- shortens onset of LA analgesia 2. shortens DOA of analgesia
what is the effect of adding ketamine to LA for epidural
effect is unclear