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166 Cards in this Set
- Front
- Back
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what is the trade name for methoxyflurane
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PENTHRANE
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what is the trade name for fluathane
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HALOTHANE
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what is the trade name for enflurane
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ETHRANE
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what is the trade name for isoflurane
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FORANE
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what is the trade name for desflurane
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SUPRANE
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what is the trade name for sevoflurane
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ULTANE
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what is the generic name for penthrane
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METHOXYFLURANE
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what is the generic name for halothane
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fluathane
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what is the generic name for ethrane
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ENFLURANE
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what is the generic name for forane
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ISOFLURANE
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what is the generic name for suprane
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DESFLURANE
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what is the generic name for ultane
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SEVOFLURANE
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what is the trade name for N2O
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nitrous oxide
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who was the 1st person to attempt to describe anesthetic depth and potency
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*John Snow
*Plomley |
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what did Merkel and Eger examine in regards to anesthetic agents
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they looked at one parameter--only abolition of movement in response to noxious stimuli
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how did Merkel and Eger describe MAC
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minimum alveolar concentration (MAC) of anesthetic at 1 atm required to abolish movement of 50% of pts in response to noxious stimuli
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what facilitates comparison of anesthesia agents
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the index of anesthetic potency which is described by MAC
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what does MAC measure
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alveolar concentrations at equlibrium
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what is true regarding inspired and alveolar pressures
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they are equivalent
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alveolar and brain partial pressures should be what at equilirium
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the SAME
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how is MAC defined in relation to atm
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it is defined in terms of % of 1 atm
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when would it be inappropriate to measure MAC and why
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in the 1st couple of breaths taken b/c it needs time to equilibrate
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concentration of IA in alveolar mirrors concentration where
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in the CNS
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MAC represents anesthetic activity where
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at the site of action (CNS)
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what is MAC applied to in relation to inhaled anesthetics
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ALL inhaled agents
*unlike clinical signs |
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what makes comparison of IA with MAC different than comparison using clinical signs
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clinical signs rely on side effects and vary from 1 drug to another -- MAC does not
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what is the noxious stimuli used humans in relation to MAC
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surgical skin incision
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what is the noxious stimuli used in animals in relation to MAC
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*tail clamp
or *SQ electrical current |
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what is one MAC
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minimum alveolar concentration of inhaled anesthetic at 1 atm which prevents skeletal muscle movement to noxious stimuli in 50% of pts
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MAC concentrations produce what in terms of CNS depression
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EQUIVALENT depression
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MAC may produce DIFFERENT effects on what parameters
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*ventilation
*BP *CO |
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which causes greater depression of CO enflurane or isoflurane at 1 MAC
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ENFLURANE
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which IA does NOT suppress CO
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ISOFLURANE
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what is the relationship of MAC to the dose-response curve
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it represents only ONE point (movement to noxious stimuli)
-the other points on the curve may not be parallel |
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T or F
MAC values are not additive |
FALSE
MAC values ARE additive -therefore by adding 2 agents you can get the same effect on the CNS as 1 MAC of either agent alone |
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what is the only agent that you can combine with other agents to equal 1 MAC
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N2O
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what is one MAC for N2O
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104%
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can N20 be used alone at 1 MAC at 1 atm
why or why not |
NO
b/c 1 MAC=104% and that would give you an inadequate level of O2 |
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1 MAC represents movement in _____% of pts
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50
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what is 1.3 MAC
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prevents movement in 95% of pts
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what is the MAC value for N2O in oxygen
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104 %
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what is the MAC value for methoxflurane in O2
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.16 %
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what is the MAC value for halothane in O2
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.75 %
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what is the MAC for enflurane in O2
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1.63 %
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what is the MAC for isoflurane in O2
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1.17 %
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what is the MAC of desflurane in O2
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6.6 %
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what is the MAC of sevoflurane in O2
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1.8 %
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how is MAC 1.3 obtained
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bump up MAC by 1/3
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what is the relationship b/t MAC and age
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is it age dependent
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regarding age when is MAC the HIGHEST
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NEWBORN
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regarding age when is MAC the LOWEST
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ELDERLY
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what is MAC at age 35
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6.6 %
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what happens to MAC after age 35
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it goes down
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what is the relationship b/t MAC and temperature
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it is temperature dependent
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what occurs with MAC with DECREASED temperature
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it DECREASES
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what occurs with MAC with INCREASED body temperature
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it INCREASES
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how much will MAC decrease per degree of body temp
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2-5 %
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what factors INCREASE MAC
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*hyperthermia
*hyperthyroidism *alcoholism *ACUTE admin of dextroamphetamine *young age |
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what factors DECREASE MAC
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*hypothermia
*severe hypotension *advanced age *opioids, ketamine *CHRONIC admin of amphetamine *reserpine, a-methyldopa *cholinesterase inhibitors *IV local anesthetics *pregnancy *severe hypoxemia *anemia *a2-agonists |
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what would be an example of acute adminstration of dextroampheamine
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*MAO inhibitors
*cocaine *ephedrine *levodopa |
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any medication or situation that causes an INCREASE in plasma stimulating NT will affect MAC how
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INCREASE it
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what affect do depleted catecholamines have on MAC
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DECREASE it
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what factors do NOT affect MAC
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*duration of anesthesia
*sex *metabolic acid-base status *hyper or hypocapnia *isovolemic anemia *HTN |
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what is the relationship b/t MAC and the oil:gas partition coefficient
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the oil:gas partition coefficent parallels anestheia requirements
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MAC can be estimated by ___ of oil:gas partition coefficient
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150
e.g. MAC for anesthesai w/ an oil: gas p.c. of 100 would be 1.5 % |
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what does the oil:gas partition coefficient describe
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how many molecules of the IA are attracted to oil vs how many will stay in the gas phase
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the more lipid soluble an IA is the _____(lower or higher) MAC is
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LOWER
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all inhalation agents are eliminated PRIMARILY through what route
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exhalation
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absorption of the IA consists of what actions or steps
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*uptake of the IA from alveoli into pulmonary cap blood
*series of partial pressures from anesthesia machine to brain *distribution in the body |
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what is the elimination routes in general for inhalation agents
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lungs and/or liver & kidneys
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what is the objective of inhalation anesthesia (definition of general anesthesia)
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to cause a state in which the body is insensible to pain and other stimuli
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how is general anesthesia achieved
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by obtaining a constant and optimal CNS partial pressure of the IA
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how does equilibration of the IA occur/work in the body
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the brain, spinal cord and all other tissues equilibrate with the partial pressure of anesthesia agent in the blood
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what does equilibrate mean
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means equal partial pressure of IA NOT equal number of molecules
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direction of movement of gases is determined by what
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PRESSURE GRADIENT
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gases move from what type of area to what other type of area
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move from areas of HIGH pressure to areas of LOW pressure
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what is Daltons Law of Partial Pressure
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*sum of partial pressures = pressure exerted by mixture
*in a mixture of gases (or vapors)the pressure exerted by each gas is the same as it would exert if it occupied the container alone |
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according to Daltons Law of Partial Pressure regarding individual gases or vapors each gas exerts a pressure _____ of other gases present
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INDEPENDENT
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according to Daltons Law of Partial Pressure the sum of partial pressures (of individual gases or vapors) equals what
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total pressures exerted by mixture
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at dry atmospheric air (760 mmHg) what percent of air is nitrogen
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79 %
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at dry atmospheric air (760 mmHg) what percent of air is oxygen
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21 %
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as % of 1 atm 1 % IA = _____ mmHG
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7.6
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as % of 1 atm 10 % IA = _____mmHg
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76
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with vapor PRESSURE how do molecules behave
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escape from the surface of a liquid to enter the space above
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with vapor pressure how is equilibrium established
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equilibrium is established b/t the molecules in the vapor phase and the molecules in the liquid phase
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how do vapor PHASE molecules behave
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they are in contant motion
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how do vapor phase molecules exert a vapor pressure
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strike walls of the container
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how does a gas become "saturated"
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when the gas above the liquid holds al the vapor that it can hold at that temperature
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the vapor pressure of a potent volatile agent depends on what factors
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*the agent itself
*the ambient temp |
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what is the vapor pressure at 20 degrees C for HALOTHANE
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244
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what is the vapor pressure at 20 degrees C for ENFLURANE
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172
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what is the vapor pressure a 20 degrees C for ISOFLURANE
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242
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what is the vapor pressure at 20 degrees C for SUPRANE
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669
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what is the vapor pressure at 20 degrees C for ULTANE
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170
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what is the vapor pressure at 20 degrees C for N2O
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gas
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what is lethal MAC
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2-3
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what is liquids boiling point
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*the temperature at which the vapor pressure becomes equal to atmospheric pressure
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what point is it that all the liquid agent changes to vapor phase
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BOILING POINT
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input includes what steps
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1-vaporizer to anesthesia machine inflow
2-vapor mixes with carrier gas (O2, air, N2O) 3-exits anesthesia machine 4-to patient breathing circuit |
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during the input phase the IA concentration is equal to
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partial pressure
1 % is equilivant to 7.6 mmHg |
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regarding temperature compensation which IA vaporizer has to be plugged in secondary to high vapor pressure
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DESFLURANE
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regarding temperature compenstion how are most gases compensated
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from the metal alloy the vaporizer is composed of
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the amt of IA picked up from inside the vaporizer with the carrier gas is based on what factors
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*vapor pressure
*temp of the liquid |
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what types of breathing circuits are there
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*rebreathing
*non-rebreathing |
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what is the flow with a rebreathing circuit
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*flow < minute volume
*gas flow is LOW (< 5 L/min) |
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what is the concentration with a rebreathing circuit
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concentration in inspired gases differs from inflow concentration
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what is flow with non-rebreathing circuit
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*HIGH flow
(5-10 L min) |
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what is the concentration with a non-rebreathing circuit
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concentration in inflow is equal to inspired gases
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what are the general characteristics of anesthesia breathing circuits
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*volume 8-10 L
*composed of rubber or plastic |
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inhalation agents are soluble in what things
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*rubber
*plastic *metal *Co2 absorbent |
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what can become a reservior for the inhalation agent
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the breathing circuit
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what factors are a function of solubilty
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concentration and partial pressure
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do dissolved gases exert pressure
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YES
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the amount of gas dissolved is determined by what factors
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*pressure of the gas
*solubility coeffcient of the gas |
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what is Henrys Law
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concentration of dissolved gas = partial pressure of gas x solubility coefficient (pp x s.c.)
*temperature is also a factor |
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how does HYPERthermia affect MAC
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INCREASES it
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how does HYPOthermia affect MAC
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DECREASES it
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which gas is the LEAST soluable (O2, N2O or Co2)
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N2O
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which gas is the MOST soluble (O2, N20 or Co2)
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Co2
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Co2 is how many times more soluble than O2
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20 x
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what are the factors that determine the amount of inhalation agent dissolved
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1-partial pressure
2-solubillity coefficient 3-temperature |
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what is the blood gas solubility coefficient of DESFLURANE
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.42
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what is the blood gas solubility coefficient of nitrous oxide
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.46
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what is the blood gas solubility coefficient of SEVOFLURANE
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.69
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what is the blood gas solubility coefficient of ISOFLURANE
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1.46
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what is the blood gas solubility coefficient of ENFLURANE
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1.9
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what is the blood gas solubility coefficient of HALOTHANE
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2.54
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what is the blood gas solubility coefficient of METHOXYFLURANE
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12
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which IA has the LOWEST solubility
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DESFLURANE
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which IA are moderately soluble
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*isoflurane
*enflurane *halothane |
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which IA has the HIGHEST solubility
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METHOXYFLURANE
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what is FI
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partial pressure/concentration of inspired agent
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what is FA
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anesthetic in the alveolar gas
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what are the typical carrier gases
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*O2
*nitrous *compressed air |
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if the system is a non-rebreathing system what is the FD/FI relationship
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FD=FI
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if the system is a rebreathing system what is the FD/FI relationship
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FI < FD
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regarding input and uptake what is FD
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inflow
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regarding input and uptake what is FI
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circuit
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regarding input and uptake what is FA
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circuit and alveoli
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regarding input and uptake what is Fa
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alveoli and blood
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what is the formula for time constant
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capacity
_______ flow =time to a 63% change |
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one time constant is how long and equals what percent change
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*30 sec
*63% change |
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2 time constants is how long and equals what percent change
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*1 min
*86% change |
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3 time constants is how long and equals what percent change
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*1.5 min
*95% change |
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4 time constants is how long and equals what percent change
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*2 mins
*98% change |
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solubility of an agent in rubber and/or plastic components does what to FA
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initially slows rate of rise of FA
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solubility of an agent in rubber and/or plastic components has what effect on emergence
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acts as a reservoir on emergence
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what occurs with FI until anesthesia tubing and soda lime are fully equlibrated with inflowing anesthetic
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it will be decreased
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changes from rubber and plastic solubililty is more pronounced with what type of agent
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more fat soluble IA
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what does DRY soda lime do to IA
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absorbs IA and decreases FI
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what are the factors that affect uptake
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1-blood/gas partition coefficient
2-cardiac output 3-alveolar to venous partial pressure difference 4-barometric pressure |
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if any factor that affects uptake is 0 what is uptake
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zero
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what are examples of "insoluble" agents
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*N20
*desflurane *sevoflurane |
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what are examples of moderately soluble agents
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*halothane
*isoflurane *enflurane |
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the amt of anesthetic that is in the alveoli reflects what
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the amt of anesthetic that is in the brain
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regarding FA/FI ratio rate of rise is SLOWER with what type of agent
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moderately soluble
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regarding FA/FI ratio rate of rise occurs more RAPIDLY with what type of agent
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INSOLUBLE
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elimination or emergence is more rapid with what type of agent
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less soluble
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elimination or emergence is LESS rapid with what type of agent
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MORE soluble
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which agents are poorly "insoluble"
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*desflurane
*N20 *sevoflurane |
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which agents are moderately soluble
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*isoflurane
*enflurane *halothane |
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which agents are soluble
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methoxyflurane
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which agents have a blood solubility in the 0.5 range
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*desflurane
*N20 *sevoflurane |
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which agents have a blood solubility in the 2 range
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*isoflurane
*enflurane *halothane |
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what is methoxyfluranes blood solubility
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12-15
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what is the 1st factor in uptake
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solubility
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