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75 Cards in this Set
- Front
- Back
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The basic action of an anesthetic in the body is largely a function of the drug's _______structure and the resulting interaction with what?
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chemical structure, cellular receptor complex
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What are some heterogenous compounds that exhibit anesthetic properties?
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-inorgaic molecule nitrous oxide
-halogenated ethers |
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What are the inorganic molecule nitrous oxide and halogenated ethers capable of binding to? and what does it cause?
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-central nervous system and spinal cord neuronal membranes to produce reversible depression
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What are some IV agents that are used in combination w/ inh gases to provide general anesthesia?
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-sedative induction agents
-analgesics -neuromuscular blocking drugs -local anesthetics |
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current practice of anesthesia dictates that what occurs with anesthetic technique?
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-allows for a quick and pleasant induction and recovery w/ maximum patient safety and efficient case load management
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what is the basic task of anesthetic administration?
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-taking a drug supplied as a liquid, vaporizing it into an anesthesia machine, and delivering it to pt's brain and other tissues via lungs
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The main factors that influence the ability to anesthetize a patient are what?
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-technical or machine specific
-drug related -respiratory -circulatory -tissue related |
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what are the primary factors that influence abosorption of the inhal. anesthetic?
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-ventilation
-uptake into the blood -cardiac output -the solubility of the anesthetic drug in the blood -alveolar-to-venous blood partial-pressure difference |
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the concentration or partial pressure of anesthetic in the lungs is assumed to be the same as where?
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in the brain
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why is the conc. of anesthetic in the lungs the same as in the brain?
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drugs are highly lipid soluble and diffusable
they quickly and easily reach equilibrium among the body compartments |
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how is the dose of an individual drug (inh. agent) expressed?
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in terms of minimum alveolar concentration (MAC)
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T or F the faster the lung concentration rises the faster anesthesia is achieved
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True
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what are two factors related to the anesthesia machine that may affect uptake early in anesthetic administration?
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1-drug solubility in the rubber and plastc machine parts
2-total machine liter flow of the gases chosen |
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all gases except _______ are potent triggering agents for MH?
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-nitrous oxide
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to avoid exposure resulting from residual tract amts of gas what should be done to the machine for a patient suspected of being susceptible to MH?
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-thorough flush of AM w/ 100% O2 at 10L/min for at least 20min
-replacement of breathing circuits and CO2 canister -draining, inactivation, or removal of vaporizers |
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what is an indicator of the speed and uptake and elimination of an anesthetic?
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blood gas solubility coefficient
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what does the blood gas solubility coefficient reflect?
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-the proportion of the anesthetic that will be soluble in the blood
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the more soluble the drug the more quickly/slowly the brain and spinal cord uptake?
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slowly
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soluble drugs stay in the blood in greater proportion than what?
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less soluble agents
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what is blood/gas solubility coefficient of iso?
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1.4 (therefore 1.4 times as much stays in teh blood a a nonreleasable fraction for every molecule that enters the tissues and produces anesthesia)
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agents with _____ solubility leave the blood quickly and enter what?
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low, tissues (producing rapid aneshtetic state)
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what is blood/gas coefficient of des?
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0.42
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what is blood/gas coefficient of sevo?
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0.6
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what is blood/gas coefficient of N2O?
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0.47
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what is MAC of sevo?
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2
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what is MAC of iso?
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1.15
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what is MAC of des?
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5.8
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what is MAC of N2O?
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105
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anesthetics move up or down a concentration gradient?
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down
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T or F anesthetic uptake slows throughout the surgical procedure?
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true
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what is the ventilation effect?
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the faster and more deeply a patient breathes or is ventilated, the faster the patient loses consciousness at the start of anesthesia and emerges at the end
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what can hinder inhalation drug administration?
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ventilation-perfusion deficits or poor lung functions
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what is overpressuring or concentration effect?
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during the first minutes of gas administration a higher concentration of teh drug than necessary for maint., or a loading dose, is delivered to speed initial uptake
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overpressuring is more effective the more or less soluble the agent?
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the more soluble the anesthetic
(overpressuring can speed the effect of slow agents but has less of an effect on relatively fast agents) |
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what is the second-gas effect?
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simulatneous administration of a relatively slow agent (ie iso) w/ a faster drug (N2O) can speed the onset of the slower agent
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what is the oil/gas coefficient an indicator of?
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potency
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the higher the oil/gas solubility the more/less potent the drug?
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the more potent the drug
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a high solubility coefficient reflects a high ______ solubility?
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lipid
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what type of drugs tend to be the most potent?
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highly lipid soluble
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of the current inh agnets what has the highest oil/gas partition coefficient, and what has the least?
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Iso is the most
Nitrous is the least |
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what is the oil/gas partition coefficient of Iso?
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99
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what is oil/gas partition coefficient of Sevo?
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50
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what is oil/gas partition coefficient of nitrous?
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1.4
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what is oil/gas partition coefficient of des?
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18.7
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in regards to oil/gas solubility what two factors are at play?
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1-how fast the drug is delivered to the tissues (blood/gas solubiliy)
2-how efficiently is can access and affect the sites of action (oil/gas solubility) |
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what are the two major influences on anesthetic uptake and distribution from the CV system?
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1-majority of blood leaving the lungs w/ anesthetic is normally distributed to the vessel rich grp
2-during indxn, increases in CO slow onset |
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what organs consist of the vessel rich group?
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heart, liver, kidneys, brain
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an increase in CO removes more anesthetic from the lungs which results in what?
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slows the rise in lung and brain concentration
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what is the effect on uptake, distribution, and elimination with modern anesthetics with regard to metabolism?
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minimal effect
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what has historically been associated various anesthetic-related toxicities?
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drug metabolism
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what three agents are least metabolized and do not result in metabolism related toxicity?
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N2O, des, iso
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what toxicity can result from halothane?
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hepatotoxity
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how does the anesthetic leave the body during emergence?
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leaves the tissues vias the blood and exits the lungs with ventilation
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routine practice is to adminster what to aid in recovery during emergence/
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100% oxygen
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if nitrous was given, 100% oxygen prevents what?
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diffusion hypoxia
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the longer the anesthetic was administered the faster or slower the patient emerges?
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slower
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what is diffusion hypoxia?
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when high conc. of rapid insoluble agent such as N2O has been given, the drug exits the body quickly through the lungs and is replaced by less soluble nitrogen in air, this results in transient dilution of normal resp gases like O2, and CO2
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nitrous oxide diffuses into where?
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air-containing cavities in the body
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what are examples of expandable air cavities?
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-air embolism
-pneumothorax -acute interstitial obstruction, -intraocular air bubbles -pneumoperitoneum |
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what types of spaces will undergo an increase in pressure?
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rigid air-containing spaces
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what types of spaces are rigid air containing spaces?
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-tympanic membrane grafting after tympanomastoid procedures
-intracranial procedures |
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what equipment can expand during nitrous oxide anesthesia and appropriate precautions and adjustments should be considered?
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-the ETT cuff
-LMA -ballon tipped pulmonary artery catheters (all may expand w/ N2O use) |
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what agent reacts the most w/ CO2 absorbent?
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sevo
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the sevo w/ Co2 abosorbent reaction increases w/ what?
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heat
total gas flows less than 2L/min |
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what can result from sevo reacting w/ dessicated CO2 abosorbants?
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compound A
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Carbon monoxide production has been reported after use w/ what two agents?
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des and sevo
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T or F the uptake of anesthetic drugs is faster in children than adults
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True
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what accounts for the fact that anesthetic uptake is quicker in kids than adults?
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the child's higher alveolar ventilation per weight
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infants and children has higher or lower cardiac output per weight than adults?
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higher
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the higher the cardiac output the _____ the onset?but how is this effect minimized in kids?
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slower, the infant's lower muscle mass allows for more of agent to concentrate in the vital organs with overall effect to promote uptake to brain
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anesthetic are more or less soluble in kids than adults?
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less blood soluble
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the MAC in kids is higher or lower and does what with age?
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The MAC is higher in children and decreases with increasing age
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what can reduce the incidence of emergence agitation in kids?
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administration of fentanyl or dexmedetomidine
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what two drugs have no effect on emegence agitation?
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propofol
midazolam |
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how does obesity affect anesthetic induction and emergence?
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minimal clinical effects on induction, emergence may be slower because of disposition of anesthetics in fat
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