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174 Cards in this Set

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With the exception of prilocaine and hexylcaine, what molecular class do the majority of injectable local anesthetics fall under?
Tertiary Amines
(Prilocaine and hexylcaine are secondary amines)
What part (lipophobic or lipophilic) is the largest of the molecule?
Lipophilic
True or False: All local anesthetics posses hydrophilic and lipophilic characteristics.
True; this is called amphipathic
True or False: Local anesthetic parts with a hydrophilic part are not suited for injection but are good topical anesthetics (i.e. Benzocaine)
False; Local anesthetics WITHOUT a hydrophilic part are not suited for injection, but make good topical agents
What are the two chemical classes that local anesthetics can be according to their linkage?
1) Amino Esters
2) Amino Amides
True or False: Ester-linked local anesthetics (procaine) are readily hydrolyed in aqueous solution.
True
True or False: Amide-linked local anesthetis (lidocaine) are relatively resistant to hydrolysis.
True
Which class, amide or ester local anesthetics, are excreted in a greater percentage in the urine unchanged?
Amides
List three properties of local anesthetics as prepared in the labratory:
1) Weakly Basic
2) Poorly soluble in water
3) Unstable when exposed to air
In this form, they are of little clinical value
What do local anesthetics combine with to form salts? Why is this relevant?
They combine with acids to form local anesthetic salts which are quite soluble in water and comparatively stable; thus most LA's are dispensed as salts (Hydrochloride, most commonly)
What is the pH of normal tissue?
7.4
What is the pH of inflamed tissue?
5 to 6
True or false: Manufacturers often acidify local anesthetics that contain epinephrine to prevent oxidation of the vasopressor?
True; this pH is usually around 3.3 whereas the pH of solutions w/o epinephrine is 5.5
Name two results of injecting into an area of inflammation?
1) Burning sensation on injection
2) Reduced efficacy of local anesthesia
True or False: Increasing the pH (more basic) of a local anesthetic solution speeds its onset of action, increases effectiveness, and makes the injection more comfortable.
True
True or False: The ability of a local anesthetic to block nerve impulses is profoundly altered by changes in intracelluar pH.
False; it is affected by EXTRACELLULAR pH. The nerve or intracellular pH remains rather stable
Fill in the blank: For clinical use, local anesthetics are available as ________.
Salts
In solution, the local anesthesia salt exists simultaneously in what two forms?
1) RN or base (uncharged, lipid-soluble)
2) RNH+ or cation (charged)
True or False: The proportion of each ionic form (RN or RNH) in solution varies with the pH of the solution or surrounding tissues?
True
In the presence of many hydrogen atoms (high concentration = high acidity = low pH), what form does most of the anesthetic solution exist as?
Cationic (i.e. RNH+ > RN + H+)
As the number of hydrogen ions decrease (i.e. low concentration = low acidity = high pH), the equilibrium shifts which direction?
The equation shifts to the right (i.e. RNH+ < RN + H+)
What is the pKa a measure of?
The pKa is also known as the dissociation constant and is a measure of a molecule's affinity for hydrogen ions (H+)
When the pKa of the local anesthetic = the pH of the solution, what percentage exists of both the base and the cation?
They are exactly proportional (i.e. 50% of the drug exists as RNH+ and 50% exists as RN)
What is the Henderson-Hasselbalch equation?
It determines the percentage of drug existing in either form (i.e. base or cation). The formula is as follows:

Log (Base/Acid) = pH-pKa
Name the two factors involved in the action of a local anesthetic on the nerve membrane:
1) Diffusion of drug through the nerve sheath
2) Binding at the receptor site in the ion channel
What form of the drug is responsible for diffusion through the nerve sheath?
RN (uncharged, lipid-soluble, base)
From the axoplasmic side, what ions enter the sodium channels and bind to the receptor sites and are ultimately responsible from the conduction blockade that results?
RNH+
Of the two properties, diffusion and binding, which is more important in actual practice when it comes to local anesthetic effectiveness?
Diffusability
True or False: The rate of onset of anesthetic action is related to the pKa (drug's affinity for H+ molecule) of the local anesthetic.
True! High pKa = low RN form to diffuse through the nerve membrane (if pH of surrounding tissue is around 7.4). Low pKa = abundance of RN to diffuse through membrane; however, once inside the axoplasm, only a small number of base molecules regroup back to the cationic form necessary for binding to the receptor site, thus anesthetic action is inadequate
In inflamed tissue, why is the succeeding round of RN base molecules not as great in number in crossing the membrane as the initial wave of RN molecules (Sum total is less)?
Because of the greatly increased absorption of anesthetic molecules due to increased vascularity
True or False: Local anesthetics are clinically effective on both axons and free nerve endings?
True
What kind of membrane do topical anesthetics easily penetrate?
Mucous membranes and (injured skin)
To increase clinical effectiveness of topical anesthetics, the pH is often raised. Why?
Increasing the pH of the drug provides more base form (RN) for diffusion and dissociation to the active cation form at free nerve endings
Individual nerve fibers are also known as ____.
Axons
What is the function of the endoneurium?
To separate indvidual nerve fibers (axons) from each other.
The _________ binds nerve fibers together into fasciculi.
Perineurium; The thicker, the slower the rate of local anesthetic diffusion across it
What is the innermost layer of the perineurium?
Perilemma
What problem does the perilemma/perineurium pose to local anesthetics?
It is the main barrier of diffusion into a nerve
True or False: The epineurium has a tight consistency?
False; it is loose connective tissue where local anesthetics are able to readily diffuse through
What layer do blood vessels and lymphatics traverse through?
Epineurium; the vessels absorm the local anesthetic molecules, thus removing them from the site of the injection
True or False: The epineural sheath or nerve sheath constitutes a barrier to diffusion of local anethetics.
False
Define diffusion.
The unhindered migration of molecules or ions through a fluid medium under the influence of the CONCENTRATION GRADIENT.
True or False: The greater the initial concentration of the local anesthetic, the faster is the diffusion of its molecules and the more rapid its onset of action.
True!
What are mantle bundles and where are they located?
Mantle bundles are fasciculi or bundles of nerve fibers (axons) and they are located near the surface of ther nerve
True or False: Mantle bundles are the last ones reached by the local anesthetic and are exposed to a higher concentration of it.
The first part of the statement is FALSE, they are reached first; the second part of the statement is TRUE. Mantle bundles are usually blocked completely shortly after the injection
Fasciculi found closer to the center of the nerve are called ________ bundles.
Core
Why is it that core bundles are contacted by a local anesthetic after much delay and a lower anesthetic concentration?
Because of the greater distance that the solution must traverse and the greater number of barriers it must cross
True or False: Amide anesthetics undergo almost immediate enzymatic hydrolysis once within the tissues.
False; ESTER anesthetics do
Complete conduction blockade of all nerve fibers in a peripheral nerve requires an adequate _________ and ________ of local anesthetic.
1)Volume
2)Concentration
Which regions do the mantle and core fibers tend to innervate?
1) Mantle: More proximal regions like molar areas with an IA
2) Core: More distal regions of the nerve like the incisors and canines with an IA
Define Induction Time.
The period from deposition of the anesthetic solution to complete conduction blockade
True or False: Although molecular forms of the anesthetic are important in neural blockade, drugs with a lower pKa possess a more rapid onset of action than do those with a higher pKa.
True!
Name some physiochemical factors of a local anesthetic that influence its clinical characteristics.
1. Dissociation Constant (pKa)
2. Lipid Solubility (i.e. lipophilic nerve membrane)
3. Protein Binding (i.e. at receptor sites = longer duration)p.24
4. Vasoactivity
4.
When emerging from a LA block, why is it that the molars will "wake up" before the incisors?
Because the mantle fibers which innervate the molars lose the local anesthetic much earlier than the core fibers which innervate the incisors
Define Tachyphylaxis.
An increasing tolerance to a drug that is administered repeatedly. It is much more likely to develop if nerve function is allowed to return before reinjection
Name some factors most likely associated with the development of Tachyphylaxis
1) Edema (isolate nerve from LA)
2) Localized hemorrhage(isolate nerve from LA)
3) Clot formation (isolate nerve from LA)
4) Transudation (isolate nerve from LA)
5) Hypernatremia (raises sodium ion gradient)
6) Decreased pH of tissues (due to first injection of acidic LA, fewer LA molecules are transformed into the free base to traverse across membrane)
Name three factors that are associated with the rate at which an anesthetic is removed from a nerve.
1) Protein binding
2) Vascularity of the injection site
3) Presence or absence of a vasoactive substance
List the most desirable properties of a local anesthetic.
1) Not irritating to tissue at which it is applied
2) Not cause permanent alteration of nerves
*3) LOW SYSTEMIC TOXICITY
4)Effective injected and/or applied locally
5) Time of onset is short
6) Duration is long enough for procedure but short enough so there is no extended recovery
7) Potency sufficient to give complete anesthesia w/o use of harmful concentrations
8) Relatively free from producing allergic reactions
9) Should be stable in solution and readily undergo biotransformation in body
10) Should either be sterile or capable of being sterilized by heat without deterioration
List the methods of inducing anesthesia.
1) Mechanical trauma
2) Low temperature
3) Anoxia
4) Chemical irritants
5) Neurolytic agents (alcohol, phenol)
6) Chemical agents (local anesthetics)
*We desire TRANSIENT or COMPLETELY REVERSIBLE methods
Define Local Anesthesia
A loss of sensation in a circumscribed are of the body caused by a DEPRESSION of excitation in nerve endings or an INHIBITION of the conduction process in peripheral nerves...without loss of consciousness (separating factor from general anesthesia)
What is another name for a Sensory nerve?
Afferent (SAME)
Where does the sensory nerve travel?
To the CNS
Name the three parts of the sensory nerve.
1) Dendritic zone
2) Axon
3) Cell body
True or False: The cell body of the sensory neuron is located between the axon and the dendrites and plays a role in both 1) nerve transmission and 2) metabolic support
False; this is a definition of the motor neuron
Where is the senory neuron located?
Away from the axon or main pathway of nerve transmission
What is the primary function of the sensory neuron?
To provide metabolic support for the entire neuron
What is another name for a motor neuron or nerve?
Efferent (SAME)
Which direction does the motor neuron travel?
Away from the CNS toward periphery
The motor neuron plays a role in both _______ ____________ and _________ ________ for the cell.
1) Nerve transmission
2) Metabolic support
What does the axoplasm do?
Provides metabolic support
What does the nerve membrane consist of?
1) Bilipid layer of phospholipids
2) Associated proteins (receptor sites), lipids, and carbohydrates
What are the Nodes of Ranvier?
Portions of the nerve membrane exposed directly to the extracellular medium
Name 4 ways in which an impulse can be initiated.
1) Chemical
2) Thermal
3) Mechanical
4) Electrical
True or False: An impulse loses its energy as it propagates along a nerve fiber.
False; it does not lose energy rather it remains constant
What is the charge of a nerve at resting potential?
-70mV
Name the three essential components of the local anesthetic armamentarium.
1) Syringe
2) Cartridge
3) Needle
What is the ADA's criteria from acceptance of local anesthetic syringes?
1) Must be durable and able to withstand repeated sterilization w/o damage (if disposable, packaged in a sterile container)
2) Capable of accpeting a wide variety of cartridges and needles of different manufacturers, and permit repeated use
3) Inexpensive, self-contained, lightweight, and simple to use w/one hand
4) Should provide for effective aspiration and be constructed so that blood may be easily observed in the cartridge
What is the most commonly used syringe in dentistry today?
Breech-loading, metallic, cartridge-type syringe
What is the major factor influencing the ability to aspirate?
Gauge of the needle
What are some advantages of a pressure syringe?
1) Trigger permits measured does administration
2) Enables a relatively weak (muscularly) administrator to overcome the significant tissue resistance that is encountered during a PDL injection
Who introduced the hypodermic syringe?
Alexander Wood
What is the primary use of a jet injector?
To obtain topical anesthesia before the insertion of a needle; it may also be used for mucosal anesthesia of the palate
True or False: The jet injector is an adequate substitute for the more traditional needle and syringe in obtaining pulpal or regional block anesthesia
False
When should a disposable syringe be considered for use?
Only when a traditional syringe is not available or cannot be used (i.e. severe latex allergy, diphenhydramine is used as a local anesthetic is presumed cases of LA allergy)
Is the use of a safety syringe recommended by the author?
Yes
What does CCLAD stand for?
Computer-Controlled Local Anesthetic Delivery Systems
In a CCLAD injection, what explains the reduced pain perception noted by most patients during the injection?
The controlled rate of fluid administration
After administering one cartridge of anesthetic, you switch it out for a new cartridge. It begins to leak as pressure is applied. What could be the problem?
The needle did not penetrate the diaphragm in the center (ovoid puncture) allowing leakage of the solution
Why does disengagement of the harpoon occur? When is this most likely to happen?
Because it is dull or the administrator applies too much pressure during aspiration. Disengagement is most likely to occur when a 30-guage needle is being used because there is significant resistance produced within the needle lumen as aspiration is attempted
Who would most benefit from a self-aspirating syringe?
Practitioners with small hands
List the components of the needle.
1) Bevel
2) Shaft
3) Hub
4) Cartridge-penetrating end
True or False: A needle whose point is centered on the long axis will deflect less than a beveled-point needle whose point is eccentric.
True
When selecting a needle for an injection, what two factors should be considered?
1) Gauge
2) Length
True or False: The smaller the number (or gauge), the greater the diameter of the lumen.
True
What are some distinct advantages of larger-gauge needles over smaller ones?
1) Less deflection...
2) Which causes greater accuracy in insertion which leads to increased success rates (especially in injections where the depth of soft tissue being penetrated is significant)
3) Needle breakage less likely to occur
4) Aspiration of blood is possibly easier and more reliable through a larger lumen
5) No perceptual differences in patient comfort
When is the use of larger-gauged needles recommended?
For any injection technique used in a highly vascular area or when needle deflection through soft tissue would be a factor (i.e. inferior alveolar, posterior superior alveolar, mental or incisive nerve block)
True or False: The 27-gauge is the preferred needle for all injections presenting high risk of positive aspiration.
False; the 25-gauge is the preferred needle, the 27 can be used for all other injection techniques provided the aspiration percentage is low and tissue penetration depth is not great
What injection is the 30-gauge needle specifically recommended?
None, although it may be used in instances of local infiltration as when obtaining hemostasis during periodontal therapy
True or False: The greater the angle of the bevel, the lesser the degree of needle deflection.
False; the greater the deflection
What is BRIT?
Birotational insertion technique; A technique in which the operator rotates the handpiece or needle in a back and forth rotational movement while advancing the needle through tissues. Can be used with a CCLAD device
What are the average lengths for short and long needles?
20mm and 32mm, respectively
When is a long needle preferred?
For all injection techniques where the penetration of significant thicknesses of soft tissue is required
When is a short needle preferred?
Short needles may be used for any injection in any patient who does not require the penetration of significant depths of soft tissue
Why do we change the needle after 3 to 4 injections?
Because it becomes dull and can cause pain and trauma to the tissues.
According to Malamed, which needle is the only needle necessary in a dental office?
25-gauge long; however, he states that it is practical to have a second needle available(25 or 27-gauge short)for injections in which the soft tissue thickness is less than 20mm and where the risk of positive aspiration is minimal, and in areas where stabilization of a long needle might be difficult (i.e. maxillary anterior teeth and palate)
Needles should not be bent if they are to be inserted into the soft tissue to a depth of __ mm.
5; There is no injection technique in which the needle enters into the soft tissue that mandates that the needle be bent for an injection to be successful
True or False: According to Malamed, no attempts should be made to change the direction of a needle when it is embedded in tissue
True
Name the 4 parts of the cartridge.
1) Cylindrical glass tube
2) Stopper (plunger, bung)
3) Aluminum cap
4) Diaphragm
True or False: Cartridges whose plungers are flush with or extruded beyond the glass of the cylinder are fine to use as long as the cartridge is inspected for cracks or leakage.
False
What group of people might need special consideration when administering a local anesthetic through a glass cartridge? Why?
Persons with latex allergy due to the latex rubber diaphragm
How can the number of milligrams of an agent be calculated?
By multiplying its percent concentration (i.e. 20%=2.0mg/mL) by total volume of cartridge (i.e. 1.8mL in U.S. or 2.2mL in U.K.). Thus, 1.8mL cartridge of a 2% solution contains 36mg of a drug.
True or False: The local anesthetic drug is not stable or capable of being autoclaved, heated, or boiled without breaking down.
False; it is stable and capable of the above mentioned things. However, the vasopressor drug and/or cartridge seals are more easily destroyed
Why is the vasopressor drug included in most anesthetic cartridges?
To increase the safety, duration and depth of action of the local anesthetic
True or False: The pH of dental cartridges containing vasopressors is lower or more acidic compared to those that do not contain a vasopressor (3.3 to 4.0 versus 5.0 to 6.0. Thus, plain local anesthetics have a slower onset of action and cause more "burning" upon injection.
The first statement is true; the second statement is false. Plain local anesthetics have a quicker onset of action (more free base to penetrate membrane) and are more comfortable on injection
Cartridges containing vasopressors also contain an antioxidant. What is the name of the antioxidant added?
Sodium (meta) bisulfite
What does sodium (meta) bisulfite do?
Prevents oxidation of vasopressor by reacting first with oxygen that was either trapped in the cartridge or oxygen that has seeped in. This reaction prevents the oxygen from destroying the vasopressor
What does sodium bisulfite oxidize to and which form has a lower pH?
Sodium bisulfate which has a lower pH thus increased "burning" upon injection if an older cartridge is being used over a newer one
Why is sodium chloride added to the cartridge?
To make the solution isotonic with the tissues of the body
What is the diluent that provides the volume of solution in the cartridge?
Distilled water
If a doctor gets the "urge" to "sterilize" a cartridge before administering, what should he or she do?
Wipe the exterior of the cartridge with an isopropyl(91%) or ethyl (70%) alcohol-dampened wipe. There should be no liquid alcohol present around the cartridges
Why are cartridge warmers not necessary?
Overheating the LA soluction can lead to patient discomfort and destruction of the heat-sensitive vasopressor
What is the "bubble" that is sometimes seen in local anesthetic cartridges?
Nitrogen gas
When a stopper is visibly extruded, what conclusions can be made? Is this a problem?
The cartridge was frozen thus causing the liquids within to expand. This is a problem because it means that the cartridge can no longer be considered sterile and should not be used for injection (Extruded stopper can be seen with and without a bubble. Without, indicative of prolonged storage in chemical disinfectant and diffusion of solution into cartridge)
"Burning" sensation upon injection may be the result of what four things.
1) Normal response to the pH of the drug
2) Cartridge containing sterilizing solution (i.e. alcohol that has seeped in; more intense burning)
3) Overheated cartridge
4) Cartridge containing a vasopressor
If a cartridge has a corroded cap, what can be concluded?
It was immersed in a cold sterilizing solution (the metal and disinfecting salts are not compatible)and should not be used
What does rust on a cartridge indicate?
That at least one cartridge in the tin storage container has broken or leaked. Cartridges should not be used if they contain rust
Name one commonly used antiseptic.
1) Betadine (povidone-iodine)
2)Merthiolate (thimerosal)
Why should antiseptics that contain alcohol be avoided?
Because the alcohol is irritating to the tissues
What class of local anesthetic is benzocaine?
Ester
True or False: The likelihood of allergic reactions to esters (topically) is significantly greater than that to amide topical anesthetics.
True
Why is it that allergic reactions to benzocaine are usually localized?
Because benzocaine, although an ester (increased chance of allergy), is not absorbed systemically
Of the amides, which one possesses topical anesthetic properties in clinically acceptable concentrations?
Lidocaine
True or False: The risk of overdose with ester topical anesthetics is greater than that with amide anesthetics.
False; it is the opposite
What does EMLA stand for and what does it consist of?
Eutectic mixure of local anesthetic; Lidocaine and prilocaine. It is designed to provide topical anesthesia to intact skin
Why should only small, metered doses of topical anesthetic sprays be used?
Because topical anesthetics require greater concentration to penetrate mucous membranes, and because topical anesthetics are rapidly absorbed by the cardiovascular system
Nerve conduction depends on two factors. Name them.
1) Concentration of electrolytes in axoplasm (or interior of cell) and extraceullular fluids
2) Permeability of nerve membrane to Sodium and Potassium
In order for firing threshold to be reached, how many millivolts must the charge decrease by?
15 mV
True or False: Local anesthesia increases the firing threshold, leading to a need of less Na+ to create an action potential.
First part of the statement is true, the second part of the statement is false. More Na+ is needed within the membrane to create an action potential
During repolarization, what is required to establish equilibrium of potassium and sodium?
ATP energy and their respective pumps
Define Action Potential.
Transient depolarizations of a membrane that result from a brief increase in permeability of the membrane to sodium and usually a delayed increase in permeability to potassium
List the steps to an action potential.
1) Stimulus excites nerve (Resting potential of nerve = -70mV
2) Slow depolarization (electrical potential within nerve becomes slightly less negative; remember...it must reach a change of 15 mV before rapid depolaraization. 15 mv is considered "firing threshold")
3) Rapid depolarization (threshold, potential or firing threshold which leads to reversal of electrical potential = +40 mV on interior of nerve)
4) Repolarization
True or False: The influx of Na+ and efflux of K+ require ATP energy during an action potential
False; this process is passive during the action potential. However, during repolarization, ATP energy is required
What does the myelin sheath allow?
Faster nerve conduction
With the exception of Cocaine, what is the action produced by local anesthetic drugs?
Vasodilation
Cocaine is the only local anesthetic that produces vasoconstriction. It inhibits the uptake of __________ into tissue binding sites.
Catecholamines (especially norepinephrine)
When applied topically, local anesthetics are taken up most rapidly by which mucous membrane?
Tracheal mucosa (followed by pharyngeal then esophogeal and bladder mucosa)
Once absorbed into the blood, local anesthetics are distributed throughout the body to all tissues. What tissue and/or organ contains the greatest percentage of local anesthetic than any other in the body? Why?
Skeletal muscle; this is because it constitutes the largest mass of tissue in the body
The "blood level" of the anesthetic is influenced by which three factors?
1) Rate at which drug is absorbed into the CVS
2) Rate of distribution of the drug (more rapid in health patients)
3) Elimination of the drug through metabolic or excretory pathways
What is the main excretory organ for both the amide and ester local anesthetics?
Kidneys
What is a byproduct of procaine that is linked to allergic reactions?
PABA
When is the use of ester local anesthetics relatively contraindicated?
When the patient has atypical plasma pseudocholinesterase
Your client has marked "difficulty" during general anesthesia on her health history. What should you be cautious of?
The use of ester local anesthetics due to the probable genetic inheritance of atypical plasma cholinesterase (inability to hydrolyze ester local anesthetics and other chemically related drugs such as Succinylcholine that is used to induce general anesthesia)
Where are ester local anesthetics biotransformed (metabolized)?
In the plasma by the enzyme plasma cholinesterase
What is the main site of metabolism for amide local anesthetics?
Liver
Prilocaine undergoes primary metabolism in the liber. Where else could it possibly be metabolized?
Lungs
True or False: Liver funcion and hepatic perfusion significantly influence the rate of biotransformation of an ester local anesthetic.
False! Amide local anesthetic
What ASA classes are considered relative contraindications to receive amide local anesthetics?
ASA IV and V (significant liver dysfunction or heart failure)
Which drug is associated with methemaglobinemia?
prilocaine
Does significant renal disease (ASA IV or V) indicate a relative contraindication for both amide and ester local anesthetics?
Yes; this includes patients undergoing renal dialysis, and those with chronic glomerulonephritis or pyelonephritis. Patients with such problems may be unable to eliminate the parent LA compound or its metabolites from the blood resulting in elevated blood levels and increased potential for toxicity
What is the pharmacological action of LA's on the CNS?
Depression, there is a spectrum of symptoms depending on the blood levels (low vs. high)
What is a sign or symptom that is an "exception" to the direct depressant action of the local anesthetic on the CNS?
Circumoral and lingual numbness; these are not caused by CNS depression but rather is the direct result of high blood levels of LA reaching the highly vascular area of the mouth
You administer an IA on the left side. Ruling out crossover innervation, your client complains of bilateral mandibular numbness. Why should you be concerned?
The anesthetic dose administered was too high and has been transported to those tissues by the CVS
True or False: If either excitation or sedation appears within 20 to 30 minutes after the intraoral administration of a local anesthetic, it should serve as a warning to the clinician of a rising local anesthetic blood level and the possibility of a more serious reaction.
False; within the first 5 to 10 minutes
Although not known for sure, where within the CNS is the local anesthetic thought to exert its effect?
At the inhibitory cortical synapses or directly on the inhibitory cortical neurons
True or False: Local anesthetics have a direct action on the mycardium and peripheral vasculature.
True
Which of the two systems, CNS or CVS, is more resistant to the effects of local anesthetic drugs?
CVS
Local anesthetics produce a myocardial ________ that is related to the local anesthetic blood level.
Depression
True or False: Local anesthestics decrease eletrical excitability, decrease the conduction rate, and decrease the force of contraction of the heart
True
At what blood level will signs and symptoms of local anesthesic overdose be noted?
If the blood level rises past 6 ug/mL
What is the primary effect of local anesthesia on blood pressure?
Hypotension
With the exception of Cocaine and ropivacaine, what effect do local anesthetics have on peripheral vasculature?
Vasodilation; through relaxation of the smooth muscle in the walls of the blood vessels (increased blood flow = increased rate of drug absorption = decreased depth and duration of anesthesia and increaed bleeding and increased LA blood levels)
True or False: Negative effects on the CVS are not noted until significantly elevated blood levels of LA are reached.
True; see page 37 of Malamed
What effect do local anesthetics have on the respiratory system?
1) Nonoverdose levels-- direct relaxation on bronchial smooth muscle
2) Overdose levels-- may produce respiratory arrest as a result of generalized CNS depression
From the following description, name the associated pharmacogenic disorder: Acute clinical manifestations include tachycardia, tachypnea, unstable blood pressure, cyanosis, respiratory and metabolic acidosis, fever, muscle rigidity, and death. Many commonly used anesthetic drugs can trigger the manifestation of this disorder.
Malignant Hyperthermia