Term
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Definition
Halogenated methyl ethyl ether- Non-flammable
vapor pressure: 243 mmHg
B/G coeff: 1.4
MAC: 1.2
OTHER: <1% metabolized, potentiates skeletal muscle relaxation, VERY mild analgesic effects |
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Term
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Definition
suggests that lipid solubility correlates with potency. Points to lipophilic/hydrophobic action in some region of the brain.
Alters fluidity of membrane |
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Term
| unitary theory of narcosis |
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Definition
| All anesthetics have a common method of action |
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Term
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Definition
Mullins expanded on the Meyer-Overton theory-
absorption of anesthetic molecules could expand the volume of a hydrophobic region within the cell membrane and subsequently distort channels necessary for sodium ion flux and the development of action potentials necessary for synaptic transmission |
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Term
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Definition
volume of a gas varies inversely with the pressure if moles and temp constant.
P1V1=P2V2 |
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Term
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Definition
Volume of gas varies directly with absolute temperature (K) if pressure and moles are held constant.
V1/T1=V2/T2 |
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Term
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Definition
Pressure of a gas is directly proportional to the absolute temp. (K) of the gas if moles and volume are held constant.
P1/T1=P2/T2 OR P1T2=P2T1 |
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Term
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Definition
Useful for when variables change simultaneously:
P1V1/T1=P2V2/T2 |
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Term
| Dalton's Law of Partial Pressures |
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Definition
A mixture of gases exerts a pressure that is the sum of the pressures that each gas would exert if it were present alone under the same conditions.
Ex: at sea level the sum would be 760mmHg
Pt= P1+P2+P3+... |
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Term
| What Reynold's numbers correlate with laminar and turbulent flow? |
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Definition
Laminar= 1000 or less
Turbulent= 1500 or more
If number in between these, it is hard to predict whether it will be laminar or turbulent |
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Term
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Definition
Rate of diffusion is PROPORTIONAL to membrane area, partial pressure gradient, and solubility of a gas
Rate of diffusion is INVERSELY PROPORTIONAL to the membrane thickness and molecular weight |
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Term
| Graham's law of diffusion |
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Definition
The rate of diffusion of the gases is inversely proportional to the square root of the density of the gas.
The more dense a gas is, the less well it will move and diffuse across membranes |
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Term
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Definition
The amount of a gas that will dissolve in a liquid is proportional to the partial pressure of the gas in the gas phase.
So, if you increase the partial pressure of a gas above a liquid it will increase the concentration of that gas dissolved in liquid |
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Term
| What things cause turbulent flow? |
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Definition
| high flow rates, rough tubing, kinks and bends in tubing, or sudden changes in tubing diameter. |
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Term
| T/F. concerning fluid flow, resistance is proportional to flow rate. |
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Definition
| TRUE. If you increase flow rate enough to the point that you get a lot of resistance you can turn laminar flow into turbulent flow |
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Term
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Definition
Laminar flow is DIRECTLY PROPORTIONAL to the radius of tubing and hydrostatic pressure gradient
Laminar flow is INVERSELY PROPORTIONAL to viscosity of fluid and length of tubing |
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Term
| T/F. Nitrous oxide is an excellent analgesic. |
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Definition
| TRUE. b/w 10-30% N2O produces analgesia equivalent to 10 mg morphine |
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Term
| What is the mechanism of action of N2O? |
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Definition
| Inhibition of NMDA glutamate excitatory receptors |
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Term
| T/F. N2O produces sedation by enhancing the inhibitory effects of GABA. |
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Definition
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Term
| What inhalational anesthetic(s) is/are notorious for sensitizing the heart to the catecholamines? |
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Definition
| All alkane types. Especially Halothane |
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Term
| How do most volatile anesthetics work? |
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Definition
| By enhancing GABA and holding the chloride ionophore open |
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Term
| Why do we not see enflurane (Enthrane) much anymore? |
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Definition
High doses stimulate the CNS leading to seizure-like twitching of muscle.
Also free flouride ion release that may lead to kidney toxicity seen in long procedures |
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Term
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Definition
flourinated methyl ethyl ether- non-flammable
VP: 673
MAC:6%
B/G coeff: 0.42
OTHER: ~0.02% metabolized, requires special heated vaporizer, airway irritant-- not suitable for induction without IV anesthetic |
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Term
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Definition
Flourinated isopropyl ether- non-flammable
VP: 160
MAC: 2%
B/G coeff: 0.65
OTHER: ~3% metabolized to hexaflouroisopropanol which releases free flouride ions (nephrotoxic), reacts with CO2 absorbant to form Compound A (nephrotoxic), gas flows should be at least 2L/min. |
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Term
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Definition
Inert gas/Noble gas
MAC: 63-71%
Doesn't cause MH, mechanism of action is by inhibition of NMDA glutamate receptors (w/o the neurotoxic risk of others that work by this mechanism.)
Hemodynamic functions stay intact
NOT METABOLIZED AT ALL SO WHATEVER YOU INHALE YOU EXHALE |
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Term
| explain the risk of carbon monoxide inhalation during inhalational anesthesia. |
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Definition
| CO is a degradation product of halogenated anesthetics with DRY CO2 absorbants. Desflurane is the most common followed by isoflurane. Can lead to carboxyhemoglobinemia. |
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Term
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Definition
natural alkaloid from papaver somniferum
acts primarily at mu receptors (some kappa)
associated with development of rapid tolerance
releases histamine |
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Term
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Definition
semisynthetic drug that is easily prepared from morphine-- diacetylmorphine
2x potency of morphine
VERY LIPID SOLUBLE- enters CNS rapidle causing quick euphoria
some anticancer compounds contain it |
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Term
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Definition
1/10th potency of morphine
little risk of addiction or resp. dep.
parent form: potent antitussive
partially converted to morphine in body which gives in some analgesic properties |
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Term
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Definition
2x potency of morphine
high euphoric liability
"hillbilly heroin" d/t chewing ER 160mg tablet |
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Term
| levorphanol (Levo-Dromoran) |
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Definition
synthetic morphine congener with 5x potency
less constipation and lasts longer than morphine |
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Term
| dextromethorphan (Dimetane, Robitussin) |
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Definition
A dextro-rotary isomer (D)--> NO analgesic activity.
Very good antitussive |
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Term
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Definition
1/10th potency of morphine
synthetic
*metabolized to normeperidine (CNS stimulant) which can cause seizures
C/I with MAOIs
Frequently abused b/c doesn't cause miosis and it is hard to detect |
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Term
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Definition
equipotent to morphine w/ much less sedation
longer DOA than morphine d/t slower elimination
Good to counter withdrawal symptoms |
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Term
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Definition
chemically r/t meperidine
80-100x potency of morphine
short 1/2 life of redistribution= 12.5 mins
Can be combined with neuroleptics (haldol, etc) to achieve "neuroleptic anesthesia"
Used for continuous epidural & transdermal analgesia |
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Term
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Definition
selective mu agonist
differs from fentanyl derivatives in that it has an ESTER linkage.
very short DOA d/t non-specific ester hydrolysis |
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Term
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Definition
| Drug undergoes glucuronidation making it water soluble, it gets put into biliary fluid and empties into small intestine. Bacteria from sm. intestine cleave off the glucuronide group and now the original drug remains and gets absorbed in the small intestine and the liver repeats the glucuronidation and so forth... |
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Term
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Definition
| tolerance that develops acutely within only a few doses of a drug (ex: thiopental). Per Dr. Dick, you will never get full effect no matter how high the dose |
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Term
| polymorphisms of ______ show _____ acetylation in asian population and ______ acetylation in european population. |
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Definition
| NAT (N-acetyl transferase); fast; slow. |
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Term
| T/F. Females clear drugs oxidized by CYP3A4 40% faster than males. |
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Definition
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Term
A) T/F. Females have lower pain tolerance than men.
B)T/F. Men awaken 50% faster from propofol/alfentanil/N2O anesthesia than women and may require greater doses to reach proper anesthesia |
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Definition
A) TRUE.
B)FALSE, women do |
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Term
| Discuss the 3 types of drug interactions |
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Definition
A) physiochemical- incompatability b/w physical properties of 2 drugs (precipitate formation when pancuronium added to thiopental)
B) pharmacokinetic- one drug alters the way another drug is handled by body. chronic anticonvulsant therapy enhances metabolism of NMDs
C) pharmacodynamic- drug increases or decreases effect of another drug (ex: decrease in MAC required for volatile anesthetics when opioids also given)-- it is the MOST IMPORTANT type of interaction in anesthesiology |
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Term
| What is the primary contributor to resting charge? |
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Definition
| Potassium channels (only channel open at rest) |
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Term
| T/F. dendrites and axons undergo active electrical processes |
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Definition
| FALSE. dendrites- passive, axons-active |
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Term
| What things increase conduction velocity during neurotransmission |
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Definition
1. myelination- don't have to move as many ions and open as many channels
2. |
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Term
| 1 quanta of neurotransmitter equals how many molecules of of neurotransmitter? |
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Definition
| 5,000-10,000 (each vesicle contains 1 quanta of neurotransmitter) |
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Term
| How does decreased resting potential affect conduction velocity? |
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Definition
|
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Term
| how does axonal diameter affect conduction velocity? |
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Definition
| faster conduction d/t less resistance |
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Term
| difference b/w opiates and opioids |
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Definition
opiates- agents derived from opium
opioids- all agents acting on morphine receptors (agonists and antagonists) |
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Term
| is most opioid receptor activity inhibitory or excitatory? What is it's effect on cAMP? |
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Definition
| Inhibitory, decreases intracellular cAMP. Low doses are excitatory increasing cAMP |
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Term
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Definition
LOCATIONS: mainly found in brainstem and medial thalamus. (some located in spinal cord)
FUNCTION: analgesia, respiratory depression, euphoria, miosis, physical dependence, decreased GI motility |
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Term
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Definition
LOCATION: mainly in dorsal horn of spinal cord (some in brainstem)
FUNCTION: Supraspinal analgesia, sedation, dysphoria (psychosis) |
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Term
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Definition
LOCATION: limbic system
FUNCTION: spinal analgesia |
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Term
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Definition
| newly discovered ENDOGENOUS tetrapeptides (4 amino acids) selective for mu receptors |
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Term
| What is the PRIMARY mechanism of action of the opioids? |
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Definition
| inhibition of presynaptic neurotransmitter release (NE, Ach, DA, substance P) |
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Term
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Definition
1. decreased neuronal activity
2. analgesia- raises pain threshold and pain tolerance
3. respiratory depression- decreases sensitivity to CO2, can lead to Cheyne-stokes respiration
4. Mood alteration/euphoria
5. sedation (depends on agonist)
6. miosis
7. N/V
8. Antitussive effects
9. endocrine (inhibits LHRH secretion) |
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Term
| peripheral opioid effects |
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Definition
1. Histamine release
2. venous dilation by DIRECT opioid receptor action (separate from histamine)
3. smooth muscle contraction in biliary and bladder sphincter muscles
4. inhibition of ACh release- cause of decreased peristalsis |
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Term
| Which opioids are best for cough suppression? |
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Definition
| codeine and dextromethorphan |
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Term
| Why can opioids cause muscular rigidity? |
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Definition
| they can inhibit dopamine release in the striatum (parkinson-like) |
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Term
| pharmacokinetics (ADME) of opioids |
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Definition
ABSORPTION: most well absorbed from GI tract
DISTRIBUTION: distribute well. **more lipid soluble agents reach high CNS conc. faster**
**most cross placenta well, but fetus cannot metabolize much, so conc is high*
METABOLISM: varies, but all are metabolized to some extent. most undergo large first-pass metabolism following oral dosing
EXCRETION:mainly via renal and biliary mechanisms |
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Term
| What are the 2 chemical classes of opium alkaloids? |
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Definition
| phenanthrenes and benzylisoquinolines |
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Term
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Definition
Type of opium alkaloid
4 ring system with a tertiary amine with pKa > 8.0 (mostly ionized as they are bases)
**Levo isomers more active**
examples include morphine, codeine, thebain |
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Term
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Definition
type of opium alkaloid
**Lack standard opioid activity**
papaverine: smooth muscle relaxant- PDE inhibitor- increases cAMP
Noscapine: antitussive, anticancer? |
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Term
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Definition
pure opioid antagonist
works at mu, kappa, and delta receptors |
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Term
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Definition
thebaine derivative
Pure opioid antagonist similar to Narcan, but given PO with a longer half-life |
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Term
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Definition
Partial agonist at mu receptors
structurally similar to codeine and naltrexone
less abuse potential, has been used to counteract heroin and morphine addiction without causing full-blown withdrawal symptoms |
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Term
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Definition
mixed opioid agonist/antagonist
weak agonist at kappa receptors
mu antagonist
large doses may cause dysphoria and hallucinations d/t kappa agonism |
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Term
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Definition
Mixed agonist/antagonist
antagonist at mu receptors
agonist at kappa receptors (stronger than Nalline) |
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Term
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Definition
Mixed agonist/antagonist
antagonist at mu receptors
agonist at kappa receptors (stronger than Nalline) |
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Term
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Definition
analgesic structurally similar to opioids and NSAIDS*
parent compound and active metabolite have weak affinity for mu receptors
also blocks reuptake of serotonin and norepinephrine in CNS (decreases paininfo transmission to brain)
analgesia similar to codeine-acetaminophen agents
causes dizziness, sedation, seizures, and hallucinations |
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Term
| T/F. opioids are physically and psychologically addictive |
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Definition
|
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Term
| What is neuroleptic anesthesia? |
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Definition
| a form of anesthesia induced by an injection of a butyrophenone derivative (haldol, droperidol) with a narcotic analgesic (fentanyl) |
|
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Term
| droperidol and haloperidol |
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Definition
inhibits dopaminergic neurotransmission (D2 blockade) in the CNS
Antiemetic properties |
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Term
| By what mechanisms do opioids inhibit presynaptic neurotransmitter release? |
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Definition
1. calcium channel inactivation
2. increased potassium conduction (causing cell to become hyperpolarized) |
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