Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
53 Cards in this Set
- Front
- Back
|
1) Which two factors listed below increase nerve sensitivity to local anesthetics?
a. High vascularity at the injection site b. Small axon diameter c. Extensive myelination d. High hydrophyllic character of local anesthetics |
b. Small axon diameter
c. Extensive myelination |
|
|
2) What does the abbreviation “Cm” stand for?
The minimum concentration of local anesthetic that will block nerve conduction The conduction velocity of motor nerves The minimum concentration of local anesthetic that will open nerve channels The maximum conductance time of blocked fibers |
The minimum concentration of local anesthetic that will block nerve conduction
|
|
|
3) Which ester local anesthetic has a rapid onset despite a pKa value of 9.0?
Bupivacaine Prilocaine Chloroprocaine Tetracaine |
Chloroprocaine
|
|
|
4) MLA cream consists of a 50:50 mixture of which two local anesthetics?
Bupivacaine, etidocaine Tetracaine, Lidocaine Lidocaine, Prilocaine Chloroprocaine, Prilocaine |
Lidocaine, Prilocaine
|
|
|
5) local anesthetic-induced seizures may be related to what?
An imbalance in the relative concentrations of glutamate and oxalate at medullary excitatory centers An imbalance in the relative concentrations of glycine and beta-endorphins at mu receptors An imbalance of glycine and glutamate at limbic inhibitory receptors An overabundance of glutamate in proportion to inhibitory neurotransmitters A relative overabundance of GABA in proportion to inhibitory neurotransmitters |
An overabundance of glutamate in proportion to inhibitory neurotransmitters
|
|
|
6) What is the smallest diameter single-lumen tube through which an 8F bronchial blocker and a 4mm diameter fiberoptic bronchoscope can be passed simultaneously?
8 mm ID 7 mm ID 6 mm ID 5 mm ID 4 mm ID |
7 mm ID
|
|
|
7) Most local anesthetics work by which mechanism?
Lowering the nerve membrane threshold potential Blocking ligand-gates sodium channels Inhibiting cell repolarization Blocking voltage-gates sodium channels |
Blocking voltage-gates sodium channels
|
|
|
8) Local anesthetic potency best correlates with which of the following factors?
High lipid solubility Large axon diameter Extensive myelination High vascularity at injection site |
High lipid solubility
|
|
|
9) Which block site has the greatest vascularity and therefore the highest rate of local anesthetic systemic absorption?
Intercostal Paracervical Caudal Brachial plexus |
Intercostal
|
|
|
10) When does major local anesthetic cardiovascular toxicity occur?
At a blood concentration lower than blood levels that produce seizures When blood concentrations are 3 times the level that produces seizures Only in patients with profound CNS depression Before signs and symptoms of CNS toxicity become apparent in the awake patient |
When blood concentrations are 3 times the level that produces seizures
|
|
|
11) Local anesthetic sprays that contain benzocaine can cause methemoglobinemia. Which treatment will change methemoglobin to hemoglobin?
Intravenous methylene blue Intravenous intralipid solution Thiocyanate solution Intravenous sodium bicarbonate |
Intravenous methylene blue
|
|
|
12) Which two local anesthetics from the following list are relatively selective for sensory fibers?
Mepivacaine Lidocaine Bupivacaine Ropivacaine |
Bupivacaine
Ropivacaine |
|
|
13) Which local anesthetic produces severe cardiotoxic reactions after unintentional intravascular administration that are prolonged and difficult to reverse?
Etidocaine Prilocaine Ropivacaine Bupivacaine |
Bupivacaine
|
|
|
14) Which is true for local anesthetic duration of action?
Local anesthetic duration of action is directly related to injection site vascularity High lipid-soluble local anesthetics have a longer duration of action Local anesthetic duration of action is inversely related to local anesthetic lipid solubility A low pKa is associated with longer duration of action |
High lipid-soluble local anesthetics have a longer duration of action
|
|
|
15) Which two of the following are early premonitory manifestations of local anesthetic overdose in the awake patient?
Circumoral numbness Dysrhythmias Dizziness Tonic-clonic seizures |
Circumoral numbness
Dizziness |
|
|
16) Which two from the following list are risk factors for transient neurological symptoms associated with spinal anesthesia?
Lidocaine use Elderly Lateral decubitus position Dehydration Lithotomy position |
Lidocaine use
Lithotomy position |
|
|
17) What causes bupivacaine-induced cardiovascular toxicity that is resistant to treatment?
Prolonged binding of the R(+) isomer to cardiac sodium channels Activation of the autonomic nervous system Blockage of the repolarization stage of the cardiac action potential by the racemic bupivacaine mixture Increase metabolism of myocytescAMP by phosphodiesterase activation |
Prolonged binding of the R(+) isomer to cardiac sodium channels
|
|
|
18) A local anesthetic is classified as an ester or amide based on which of the following?
Subsitutions on the benzene ring The nature of the intermediate chain Alkyl groups attached to the amine nitrogen The number of carbon atoms on the aromatic ring |
The nature of the intermediate chain
|
|
|
19) In normal tissue, which property of drugs has the greatest effect on the speed of onset of a local anesthetic?
Amide structure Degree of protein binding Intrinsic vasoconstrictor activity pKa Potency |
Intrinsic vasoconstrictor activity
pKa |
|
|
20) Five minutes after intrathecal administration of tetracaine 12mg in hyperbaric solution, a 60-year-old man has a weak hand grasp. Respirations are normal, heart rate has decreased from 80 to 45 bpm, and blood pressure has decreased from 150/80 to 90/50 mmHg. The most appropriate management at this time is what?
Administration of atropine Administration of ephedrine Administration of phenylephrine Placement of the patient in the head-down position Observation |
Administration of ephedrine
|
|
|
1. LAs exert their mechanism of action by?
|
Inhibiting the passage of Sodium through the ion selected sodium channel
|
|
|
2. In local anesthetic drugs, which drugs fraction is pharmacologically active and lipid soluble?
|
Aromatic and non-ionized.
|
|
|
3. Alkalization or carbonation of local anesthetic solution:
|
speeds the onset of action
|
|
|
4. Amide local anesthetics are predominantly metabolize by:
|
microsomal hepatic enzymes
|
|
|
5. What effect does lipid solubility have on LA potency?
|
the higher solubility the greater the potency of LA
|
|
|
6. The degree of ionization is most responsible for the speed of onset of the local anesthetics where?
|
The closer the pKa of the LA to the ph of the tissue the faster the onset
|
|
|
7. Adding epinephrine to LA will?
|
Prolong the duration of action
|
|
|
8. The following choices represent four ampules of preservative-free solution of local anesthetic agents. Which of the following have the most potential for allergic reactivity on a patient?
|
Tetracaine (because of esters)
|
|
|
9. Peak plasma concentration of LA are influenced by the site of injection. Which of the following injection site is associated with the highest absorption of local anesthetics?
|
Intercostal
|
|
|
10. Which words bellow will make the sentence true?
Alkalosis in the mother which may occur during distress during labor can result in fetal ion trapping of LA molecules in relation to placental blood flow. |
alkalosis mother and fetal ion trapping
|
|
|
11. A patient gives ahx saying: “I was told I have abnormal pseudocholinesterase and I should not get Sux, but I still want my epidural for labor.” The CRNA will do best by avoiding which LA?
|
Chloroprocaine (avoid any of the esters).
|
|
|
12. Early symptoms of LA toxicity includes:
|
Circumoral numbness
|
|
|
29.Tx of acute CNS toxicity from a LA should include:
|
administer 100% FIO2,
correction of acidosis, administration of a benzodiazepine (the answer is all of the above) |
|
|
LA toxicity can result from:
|
All of the above:
|
|
|
Accidental administration of bupivacaine IV can result in:
|
D) All of the above
|
|
|
4) What effect does lipid solubility have on LA potency?
|
The Higher solubility the Greater the potency of LA
|
|
|
7. Local anesthestics block which fibers easiest?
|
B fibers (he gave credit for C fibers)
|
|
|
Structure of LA consists of?
|
hydrophilic end, lipophilic end and hydrocarbon chain
|
|
|
Relationship of PH and PKA?
|
closer PKA and physiologic PH are to each other will have faster onset
|
|
|
Relationship between protein and lipid solubility?
|
directly related
|
|
|
Other organ that excretes LA’s?
|
lungs
|
|
|
17. Treatment for methoglobinemia?
|
--methylene blue
|
|
|
19. What is responsible for the anesthetic action of LA?
|
--lipophilic end
|
|
|
22. Most potential for allergic reaction?
|
--choice is an ester
|
|
|
31. CV toxicity related to?
|
--bupivicaine
|
|
|
33. Pt has plasma cholinesterase deficiency. Which LA do you use?
|
amide
|
|
|
34. Pick 2 amides from list?
|
--(amides have 2 “i’s”)
|
|
|
40. Lipid solubility R/T local anesthetic?
|
--increased lipid solubility results in increased potency
|
|
|
43. LA’s exert their mechanism of action by?
|
--inhibiting passage of NA through the ion selected Na channel
|
|
|
Local Anesthetics: weak bases that produce REVERSIBLE conduction blockade along central and peripheral nerve pathways.
|
Inhibiting Na ion channels in nerve membranes. Failure of Na ion channel Permeability to inc. slows the rate of depolarization such that threshold potential Is not reached and thus an action potential is not propagated. LA’s bind to the Inner gate or H gate. Unionized portion of LA’s X’s nerve cell membrane and Reequilibrizes to ionized, only ionized/water soluble can bind to inner gate and inhibit.
|
|
|
METABOLISM:
AMIDES |
By CYP-450 in liver. Prilocaine is most rapid, then lido/mepiv, then etido/bupiv/ropiv is longest acting.
|
|
|
METABOLISM:
ESTERS: |
cholinesterase (aka pseudocholinesterase & plasma cholinesterase). Choloprocaine is most rapid, then procaine, then tetracaine is slowest. Metab. Of esters= PABA= allergic rxn. Metab. Of esters is slowed with liver dz or increased BUN.
|
|
|
Cocaine is only vasoconstrictor LA used for:
|
ENT surg
|
