Anesthetic Mechanisms Flashcards Preview

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Flashcards in Anesthetic Mechanisms Deck (39):

What are the drugs used in monitored anesthesia

Midazolam for premedication, then propofol for the deeper sedation


What is the mechanism of action of propofol

GABAa agonist receptors


What are the general toxicities seen with inhaled anesthetics

-Nausea and vomiting
-Malignant hyperthermia if used with succinyl CoA


What is deep sedation

Decreased consciousness, loss of protective reflexes, no patent airway, lock of verbal responsiveness


What are the toxicity seen in the CV with local anesthetics

Block cardiac sodium channels and decrease the amount of excitability, conduction, contractility, arteriole dilation, and hypotension


What is conscious sedation

Used by dentists where the patient is awake and responsive


What is the method of epidural anesthesia

Injection into the epideral space to create a large area


What is the method of block anesthesia

Injection into the major nerve trunks, so results in a region distal to the site of injection (such as brachial plexus)


What are the toxicities of local anesthesia at low concentrations

-light headed
-visual and auditory disruptions


What are the characteristics of an anesthetic agent that high low blood solubility

Reaches high arterial pressure slowly, so it reaches equilibrium slowly, resulting in a slow onset of action


What is the mechanism that most general anesthetics work

-Activation of chloride channels for hyperpolarization (GABA and Glycine)
-Decreased excitatory channels activity


What is monitored anesthesia

Sedation based anesthetic technique for diagnostic and mino therapeutic surgical procedures, where premedication is given, then followed by another for deep sedation


What can be given to help control seizures and what is the mechanism

Benzodiazepine, which raising the threshold of seizure activity


What is the mechanism of action for local anesthetics

Blocks the voltage gated sodium channels, so there is no spread of the depolarization


What is the method of infiltration anesthesia

Direct injection into the tissues near peripheral nerve endings


What are the toxicities seen in high doses of local anesthetic

-muscle twitching and fasciculation


What is the method of spinal anesthesia

Injection into the CSF in the lumbar space in order to produce a great area


Where are ester type agents metabolized

In the plasma by circulating enzymes


Which type of fibers are most susceptible to blockage by a local anesthetic

Type C (dorsal root and SNS) > Type B (pregang) > Type A delta


What are the characteristics of a gaseous anesthetic

High vapor pressure and low boiling point, so they are gas at room temperature


Where are amide-type anesthetics metabolized

In the liver by CYP450 and excreted in the urine


What is the mechanism of action of opioid analgesics in anesthesia

Given in combination with benzo


Where do inhaled anesthetics tend to accumulate and have an effect first

The organs receiving a higher cardiac output, such as the heart, liver, and kidneys, with the muscle tissues taking much longer


What are the characteristics of effects for an anesthetia

-attenuated Autonomic responses


What is the response in the CV to inhaled anesthetics

They decrease the mean arterial pressure in direct proportion to their alveolar concentration, but increase the right atrial pressure proportionately


What is the mechanism of action of dexmedetomidine

Alpha 2 adrenergic agonist (hypnotic like state)


What are the characteristics of an anesthetic with a low blood solubility

Reaches high arterial pressure rapidly, so there is a rapid equilibrium with the brain and subsequent onset of action


What is the mechanism of action of benzodiazepines

Increased GABAa sensitivity


What are the parameters that the efficacy of inhaled anesthetics are based on

-Concentration of anesthetic in air
-Ventilation rate
-drug solubility in the air, blood, and CNS


What is the blood:gas’s partition

Relative affinity of an anesthetic for the blood compared to the inspired gas (aka blood solubility)


What is the minimal alveolar concentration (MAC)

Amount of an anesthetic to prevent a response to a surgical incision in 50% of patients


What is the mechanism of action of ketamine

NMDA antagonist


What is the reasoning that a blood soluble anaesthetic takes longer to affect the brain

Because the gas is soluble in blood, it must fist completely saturate the blood with the gas before it can affect the brain, as opposed to insoluble, which will reach maximum saturation much quicker and therefore affect the brain much faster


How can you tell between an amide and ester local anesthetic

Amide- will have at least 2 i’s in in
Ester-Will only hav ethe I in -caine


How are inhaled anesthetics eliminated, and which are eliminated the quickest

They are eliminated via the lungs, and those that are not blood soluble result in much quicker elimination


What is the toxic effect of inhaled anesthetics on the respiratory system

Respiratory depressants (reduced response to increased CO2 levels)


What are the characteristics of volatile inhaled anesthetics

Low vapor pressure and high boiling points so they are liquid at room temperature


What is the mechanism of action of barbiturates in anesthetics

GABAa receptor agonist


What is the mechanism of action of etomidate

Enchances GABA on GABAa receptors