EXAM #3 Prodigy Barash Flashcards
Through what inhibitory transmitter do inhalation and IV anesthetics exert their primary sedative and hypnotic effects?
GABA
Which narcotic is rapidly metabolized by blood and tissue esterases?
Remifentanil
Local anesthetics block the transmission of nerve impulses by targeting the function of voltage-gated _______ channels.
Sodium
Select two dose-dependent CNS depressant effects of benzodiazepines.
Hypnosis
Anticonvulsant activity
Which is the most important factor in the rate of rise of FA/FI?
Uptake
Which agent is notable for prolonging the duration of both intermediate and long-acting local anesthetics equally when added to their formulation?
Clonidine
Which of the following agents has been shown to increase intracranial pressure?
Desflurane
All have been shown to increase ICP
All volatile and N2O
2 IV agents decreasing ICP
Etomidate
Propofol
Which area is responsible for producing opioid-induced, postoperative nausea and vomiting?
Chemoreceptor Trigger zone
What may be responsible for the prolonged duration of action of vecuronium when used in intensive care unit patients?
Decreased Renal function
One of vecuronium’s metabolites,
3-OH vecuronium
3-OH vecuronium
accounts for about 60% of the activity of vecuronium and is excreted by the kidneys.The reduced clearance of this metabolite in the presence of altered renal status can result in a prolongation in the action of vecuronium.
Which of the following agents is a water-based prodrug of propofol?
Fospropofol, prodrug
Advantages of fospropofol include
Less bacteremia and HLD,less pain upon injection
After intravenous administration of fentanyl, there is an initial rapid increase in plasma concentration of the drug followed by a rapid decline in plasma administration. This initial, rapid decline is due primarily to
redistribution to highly-perfused organs
Once injected, the plasma concentration of an opioid such as fentanyl rises rapidly. Shortly after this initial rise, the plasma concentration rapidly
decreases as the drug is distributed into the highly perfused organs such as the brain, liver, and kidneys. A second, slower decrease in the plasma concentration occurs as the drug distributes into the less well-perfused tissues such as the muscles and adipose tissues
To what receptors does sugammadex bind?
It does not bind to any known receptors
Sugammadex is not known to have an affinity for any identified receptor, and it is biologically inactive. It binds
directly to steroidal neuromuscular blocking drugs.
Which of the following nondepolarizing muscle relaxants has an ED95 of 0.3 mg/kg?
Rocuronium
Simultaneous administration of a relatively slow agent such as isoflurane and a faster drug such as nitrous oxide (in high concentrations) to speed the onset of the slower agent is referred to as
2nd gas effect
Explain the 2nd gas effect?
Combined administration of a potent inhaled anesthetic with nitrous oxide can increase the alveolar concentration of the VA as the Nitrous exits the alveoli and enters the bloodstream more rapidly.
Which term describes the administration of a higher partial pressure of anesthetic than the alveolar concentration actually desired for the patient?
Overpressurization is the administration of a higher partial pressure of anesthetic than the alveolar concentration actually desired for the patient. This is used to speed induction.
All other factors being equal, which inhalation agent would exhibit the fastest emergence?
Desflurane
The elimination of the anesthetic is referred to as washout, and it’s primarily determined by the
solubility of the agent
The more soluble the agent is, the
greater it clings to the bloodstream and tissues.
The more soluble the agents the greater it clings to bloodstream and tissues, This is why emergence from a
poorly-soluble agent such as desflurane (blood:gas solubility = 0.42) occurs faster than a more soluble agent like isoflurane or sevoflurane.
Most clinicians, however, have found that gradually titrating a more soluble agent downward near the end of the case speeds
emergence.
When added to a local anesthetic, clonidine will
prolong long-acting and intermediate-acting agents equally
Local anesthetics block the transmission of nerve impulses by targeting the function of voltage-gated _______ channels.
Sodium
Which alpha-2 agonist produces analgesia via supraspinal and spinal adrenergic receptors?
Clonidine
Clonidine causes analgesia via
Supraspinal and spinal adrenergic receptors
What is the initial IV bolus of a 20 percent lipid emulsion for the treatment of local anesthetic cardiovascular toxicity?
1.5 ml/kg f/b infusion of 0.25 ml/kg/min for at least 10 minutes AFTER cardiac stability is maintained
What is the major metabolite of fentanyl?
Inactive metabolite NORFENTANYL
When administered as a premedication, the sympatholytic properties of dexmedetomidine may increase the incidence of intraoperative
Hypotension and BRADYCARDIA
Succinylcholine administration can increase the intraocular pressure
as much as 15 mmHg for about 5 minutes
All of the following are critical in determining the speed of emergence from inhalation anesthesia with a volatile agent
CO
Solubility of the agent
Minute ventilation
The lower the agent solubility, higher the cardiac output, and larger the minute ventilation, the
faster emergence will occur.
Unlike induction, in which you can use over-pressurization to speed the onset of anesthesia, you can’t under-pressurize at emergence simply because you cant
can’t reduce the inspired anesthetic below zero.
The post-tetanic count is
inversely related to the amount of time until a train-of-four twitch can be elicited
During profound neuromuscular blockade, the post-tetanic count is used to
estimate the time that is required before a response to stimulation will return.
The number of visible twitches correlates
inversely with the amount of time required for return of the first twitch of a TOF stimulation.
Which of the following is an expected respiratory effect of an inhaled anesthetic?
A decrease in tidal volume
Which opioid has the shortest half-life?
Remifentanil
Which term accurately describes the phenomenon that occurs during the recovery from anesthesia in which the washout of high concentrations of N20 can lower alveolar concentrations of oxygen and carbon dioxide?
Diffusion hypoxia
Select two treatments for an inadvertent intra-arterial injection of thiobarbiturates.
Heparin
Papaverine
Inadvertent intra-arterial injections of thiobarbiturates should be treated immediately with
intra-arterial papaverine.
Other treatment of inadvertent intra-arterial papaverine?
Heparinization as well as a sympathectomy induced by a regional anesthetic block should also be employed.
Select two agents that may shorten neuromuscular blockade in patients treated with chronic anticonvulsant therapy.
Carbamezipine
Phenytoin
Sevoflurane has been shown to produce late-phase cardiac preconditioning. What MAC level is needed to gain the maximum benefit of this effect?
1.5 MAC
Which neuromuscular blocking agent exhibits direct sympathomimetic and vagolytic effects?
Pancuronium
One of the most significant concerns with the use of nitrous oxide is its ability to.
expand an air-filled space. This can occur in any closed space that contains air including the bowel, an air embolus, or even the balloon in an endotracheal tube cuff.
During tympanoplasty, this agent contraindicated because the pressure can build up to the point that it dislodges the graft.
Nitrous oxide is contraindicated
What is the appropriate intravenous dose for succinylcholine in a 3 month-old patient?
2.0-3.0 mg/kg
Children and Defasciculating doses of nondepolarizing neuromuscular blockers
Defasciculating doses of nondepolarizing neuromuscular blockers are rarely given because fasciculations are uncommon in children
Which narcotic is rapidly metabolized by blood and tissue esterases?
Remifentanil is quickly metabolized by esterases in the tissues and bloodstream to a mildly active mu-opioid agonist and renally excreted metabolite
In general, most patients will not awaken from general anesthesia until what percentage of the anesthetic has been eliminated?
80-90%
Sevoflurane has been shown to demonstrate late-phase cardiac preconditioning. How long would you expect this cardioprotective effect to last?
24-48 hours
Volatile anesthetics exhibit cardiac.
preconditioning effects
How does VA exhibit cardiac preconditioning effect?
They appear to alter mitochondrial electron transport in myocardial cells.
It is estimated that about 30-40% of the cardioprotective effects of volatile anesthetics occurs by
reducing the overload of calcium within the cardiac cells and improving contractility.
Which patient is most likely to experience myalgia following the administration of succinylcholine?
Healthy, young adults undergoing minor procedures
What is the most successful non-pharmacological technique for lessening the pain on injection associated with intravenous propofol?
using a large, antecubital vein
Although many techniques have been used to alleviate this painful experience of IV propofopl, the most successful approach has been with the
pretreatment of a local anesthetic combined with the use of a tourniquet.
The most successful non-pharmacological technique to prevent IV propofol pain has been seen with the use of
larger antecubital veins as opposed to peripheral veins, which tend to be much smaller.
Why is edrophonium a weaker reversal agent than neostigmine?
It binds using ionic bonds while neostigmine uses covalent bonds
Which structure is characterized as an interruption of the myelin sheath that is essential for the propagation of neuron electrical signals?
Nodes of Ranvier
Which of the following statements regarding neuraxial anesthesia level is true?
Light touch sensation is blocked at a higher level than pinprick sensation
Because different neurons have a different susceptibility to local anesthetics, what happens to sensation?
specific sensations exhibit inhibition at different dermatome levels .This is referred to as differential block.
With regards to spinal anesthesia, light touch or cold sensation is
inhibited at a higher dermatome level than pinprick sensation.
Select two dose-dependent CNS depressant effects of benzodiazepines.
Hypnosis
Anticonvulsant activity
Which calcium channel blockers inhibit CYP450? (select two)
Verapamil
Cardizem
The clinical effect of benzodiazepines is due to the
Opening of Chloride channels
Specific benzodiazepine receptor sites exist on a protein complex that contains binding sites for
benzodiazepines, GABA, ethanol, barbiturates, and a chloride channel.
For Benzo receptor site, When these receptor sites are occupied by one of the drugs the
GABA receptor increases the frequency of chloride channel opening which results in hyperpolarization of the postsynaptic membrane and inhibition of neuronal transmission.
Which of the following statements correctly describes how to elicit a post-tetanic count?
A 5-second 50 Hz tetanic stimulation followed by a 3-second pause, then 1 Hz twitch stimulations
Which activity is the most sensitive determination of neuromuscular function?
Clenching the jaws and preventing the removal of a tongue depressor
Which is the most important factor in the rate of rise of FA/FI?
Uptake
Which of the following agents would produce the least amount of skeletal muscle relaxation?
Nitrous oxide
Hypercapnia in the range of 50 to 70 mmHg can produce
increased cerebral blood flow
Which local anesthetic is least protein bound?
Lidocaine
LA that are 95% bound to protein are
Ropivacaine
Bupivacaine
Levobupivacaine
LA that are 75% bound to protein are
Mepivacaine
Amide is metabolized in
liver by Hepatic carboxy-esterases
LA that are 60% bound to protein are
Lidocaine and prilocaine
Pancuronium would have a significantly prolonged duration in patients with
Renal insufficiency
Which of the following statements correctly identifies an issue that may require additional postoperative instructions after the administration of sugammadex?
Sugammadex can interfere with oral contraceptives
What concentration of epinephrine is typically added to a local anesthetic to prolong the duration of an epidural block?
1: 200,000
Sevoflurane may be less likely to result in an increase in intracranial pressure than desflurane upon emergence because it is
Less pungent
True allergy of LA are more common with
Esters
Which of the following effects of succinylcholine administration will not be prevented by the administration of a defasciculating dose of a nondepolarizing muscle relaxant?
Increased in intraocular pressure.
Remifentanil exhibits a _____ volume of distribution than fentanyl due to a(n) _____ clearance.
Smaller; increased
Which local anesthetic has been shown to decrease the effectiveness of opioids when administered together epidurally?
Chlorprocaine
What is the context-sensitive half-life of remifentanil?
2-4 minutes
Which inhalational agent has no adverse effects on cerebral physiology at normal CO2 and blood pressure?
Sevoflurane
Which of the following agents will precipitate when combined in an intravenous line with thiopental?
Vecuronium
Sugammadex has the greatest affinity for
Rocuronium
Sugammadex has about ____affinity for vecuronium
1/3
What inhaled anesthetic potentiates the effects of neuromuscular relaxants the most?
Desflurane f/b sevo, iso, and N2O
What initial arrhythmia would you most likely see in a patient experiencing cardiovascular toxicity from a local anesthetic?
Bradycardia
Cardiovascular toxicity requires much
higher plasma concentrations of local anesthetics compared to the levels for CNS toxicity
All local anesthetics can produce
hypotension, myocardial depression, and dysrhythmias,
Most commonly the first arrhythmia seen at toxic levels of LA
Bradycardia
At 1.5 MAC, which agent would maintain cerebral autoregulation more effectively?
Sevoflurane
Normally, cerebral blood flow is regulated through a range of mean arterial pressures from about
50 mmHg to 150 mmHg (some sources cite a narrower range of 60-140 mmHg).
With sevoflurane, cerebral autoregulation is maintained up until about
1 MAC. Even at 1.5 MAC, autoregulation is maintained more effectively by sevoflurane than isoflurane or desflurane.
The skeletal muscle relaxation associated with the administration of volatile anesthetics would be most evident in a patient with
Myasthenia Gravis. Skeletal muscle relaxation is most pronounced when using potent volatile anesthetics in excess of 1.0 MAC. In patients with myasthenia gravis, this effect is enhanced by as much as 40%.
IV dose of midazolam is
0.02 - 0.04 mg/kg
Because it produces less depression of EEG activity, what is the intravenous anesthetic of choice for ECT?
Methohexital
At which plasma concentration of lidocaine would analgesia first be achieved?
3mcg/ml
Hypercapnia in the range of 50 to 70 mmHg can produce
Increase in CBF
Which of the following nondepolarizing muscle relaxants would be most prolonged in the presence of severe renal disease?
Pancuronium
Succinylcholine is metabolized
By pseudocholinesterase in the plasma
Which of the following agents is classified as a piperidine?
Remifentanil
Benzo water soluble injectable form is
Midazolam
Besides using a defasculating dose of a non-depolarizing neuromuscular blocking agent, what is the most effective way to prevent myalgia from succinylcholine administration?
Pretreatment with an NSAID
Neuromuscular blocking agents work by acting on
postsynaptic nicotinic cholinergic receptors
Which agents have been noted to delay the onset of rocuronium?
Beta blockers
Rocuronium and ephedrine can speed the onset of rocuronium.
ephedrine can speed the onset of rocuronium.
Local anesthetics have been noted to potentiate
the effects of both nondepolarizing and depolarizing agents.
Larger nerves and myelinated nerve conduct impulses more quickly. Both A-delta and C nerve fibers are associated with
pain function.
Large nerve fibers are involved with
motor and sensory functions
Pancuronium would have a significantly prolonged duration in patients with
Renal Insufficiency
What are the most powerful accessory muscles of inspiration?
External intercostals
The primary muscles of expiration are the
abdominus rectus muscles and the internal intercostals.
Expiration
Internal intercostal
Inspiration
Extennal intercostal
What are the factors that most influence the response of peripheral nerves to electrical stimulation? (select two)
- placement of electrodes 2. the amount of current applied 3. duration of current. Current is measured in amps or milliamps, not volts.
In opioids with a small volume of distribution, the termination of the analgesic effect is primarily due to
Clearance of the drug
Which neuromuscular blocking agent has the fastest onset time for a typical induction dose?
Succinylcholine
Is the most cardiotoxic of the local anesthetics.
Bupivacaine
The burning felt on injection of diazepam and lorazepam is due to
preservative propylene glycol
Spinal administration of opioids gives analgesia primarily by attenuating the transmission of.
C-fiber nociceptive impulses
Local anesthetics produce a differential blockade in which different modes of nerve transmission are interrupted in an unequal fashion. Which list below demonstrates the correct order in which different nerve functions are blocked?
Temperature sensation, sharp pain, light touch
What serious side effect are you most likely to see following the administration of sugammadex?
Hypersensitivity reaction
What initial arrhythmia would you most likely see in a patient experiencing cardiovascular toxicity from a local anesthetic?
Bradycardia
Which gas law states that the total pressure of a system is the additive pressure of each individual gas in a mixture?
Dalton’s
At 1.5 MAC, which agent would maintain cerebral autoregulation more effectively?
Sevoflurane
Midazolam and etomidate are both imidazole ring derivatives.
Midazolma
Etomidate
Select two factors that may decrease the minimum alveolar concentration (MAC).
Acidosis
Hypoxia
If a patient has a true allergic reaction to a spinal anesthetic, how is it most likely to present?
pruritus and erythema
Two centrally active alpha-2 adrenergic receptor agonists that exhibit potent sedative and opioid analgesic-sparing properties.
Clonidine
Precedex
Tetracaine spinalThe addition of phenylephrine, however, does
increase the risk of TNS following a spinal using tetracaine
Which muscle relaxant would be LEAST appropriate for a patient with a history of severe asthma
Atracurium
What intravenous anesthetic has the chemical name 2,6-disopropylphenol and is insoluble in aqueous solution?
Propofol
Which local anesthetic is associated with the highest incidence of transient neurologic syndrome (TNS) when used for spinal anesthesia?
Lidocaine
