Term
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Definition
| Minimum alveolar concentration or MAC is a concept used to compare the strengths of anaesthetic vapours; in simple terms, it is defined as the concentration of the vapour in the lungs that is needed to prevent movement in 50% of subjects in response to surgical stimulus. |
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Term
| What are the effects of the steep concentration effect curve of Anest? |
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Definition
1. Population variance is very small.
2. Drugs are very reliable.
3. Genetic implications:
multiple contributing targets
OR highly conserved target |
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Term
| Why is it so important that MAC is endpoint dependent? |
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Definition
What is needed to prevent movement in
response to pain is 2-4 times higher
than that to ablate “awareness”. Pain is
relative. |
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Term
| What does the physiochemical theory state about how As work? |
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Definition
(LIPIDS OR PROTEINS) anesthetics interact with “lipoid”
components of the cell. --so there might be changed lipid or protein properties |
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Term
| Where in the brain do anesthetics act? |
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Definition
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Term
| What does the "promiscuous ligand" theory of how A work explain? |
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Definition
Low population variability.
Lack of inhibitors or antagonists.
Lack of adapation/tachyphylaxis.
Action in every living thing.
Relationship with complexity. |
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Term
| What specific molecular targets have been proposed as agents to explain A's drug mechanism? |
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Definition
| ligand gated ion channels--such as GABA gated CL channels, Glut receopt/channels, K channels, Ca channels, G protein coupled receptors |
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Term
| What specific, cellular targets have been implicated in A's mechanism? |
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Definition
| The mitochondrion seems uniquely sensitive. Nerve conduction seems to be less sensitive. |
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Term
| What is decreased BP related to? |
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Definition
| a decrease in cardiac output or decrease in peripheral restistance. Heart Rate changes are variable |
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Term
| What does a decrease in minute ventilation (produced by inhalation anesth) produce? |
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Definition
| ventilation perfusion mismatch and increased risk of hypoxemia |
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Term
| Can anesthetic metabolites produce hepatitis? |
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Definition
|
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Term
| Which A may cause neurotox? |
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Definition
|
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Term
| What does emergence rely on? |
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Definition
| Elimination via ventilation rather than metabolism |
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Term
| What are the stages of A drug processing? |
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Definition
| induction; maintenance; emergence; recovery; pain control |
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Term
| What period is most vulnerable? |
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Definition
| Recovery: (airway, nausea, pain) |
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Term
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Definition
| NO, halothane, vecuronium, or cisatracurium |
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Term
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Definition
| pancuronium, vecuronium, cistatracurium |
|
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Term
| Name Nociceptive pathway drugs |
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Definition
| PAIN: narcotics: morphine, fentanyl |
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Term
| Name short activing IV inductive drugs used to induce unconsciousness |
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Definition
| thipental, propfol, etomidate |
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Term
| What are some similarities between the anesthetic state and sleep? |
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Definition
Neurobiologic similarities:
Global decrease in neuronal activity;
Decrease cerebral metabolic rate;
EEG slowing, increased power;
Decreased EEG entropy;
Phenotypic similarities
Unconsciousness;
Amnesia;
Atonia;
Decreased heart rate;
Decreased blood pressure;
Decreased minute ventilation;
Decreased body temp; |
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Term
| What is the key difference BTW sleep and anesthetic stage? |
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Definition
|
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Term
| How is anesthesia different than analgesia? |
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Definition
| analgesics act w/o producing unconsciousness/amnesia, anesthetics produce unconsciousness w/o ablating nociceptive pathways |
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Term
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Definition
| the dose required to achieve a specific response. |
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Term
| What are muscle relaxants? What aren't muscle relaxants? |
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Definition
| drug-induced loss of muscle tone. They do not have anesthetic properties, no analgescics, no amnesia. MUST be accompanied by an anesthetic or hypnotic. |
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Term
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Definition
rapid onset/equil;
good analgesic;
bad muscle relax;
little effect on BP;
used bc it greatly decreases required dose of other anesthetiic drugs |
|
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Term
| which drug has the higest blood soluability? |
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Definition
|
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Term
| What are some key features of Halothane? |
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Definition
| potent, bad analgesic and muscle relax. MAY PRODUCE LIVER DYSFUCTION AND MASSIVE HEPATIC NECROSIS. sensitises heart to catecholamines |
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Term
| Key features of isoflurane |
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Definition
| Pungent, mod blood sol, good analgesic and muscle relax, produces tachycardia. Most used halogenated inhalant anesth |
|
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Term
| What 2 drugs might you use for short procedures? why? |
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Definition
| NO and deflurane. They have very low soluability in blood--rapid onset and elim |
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Term
| What is a reliable estimate of blood concentration after equil? |
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Definition
| alveolar anesthetiic concentration |
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Term
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Definition
| yes--0.5 MAC OF Halothane + 0.5 of halothane = 1 MAC |
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Term
| Are inhaled drugs usually used together? |
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Definition
|
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Term
| Why are inhaled As constient in their action? |
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Definition
| dose response curve--concentration for anesthetizing 5% of pop is only 20% different that anesthetizing 95% of population |
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Term
| What does it mean that MAC's halothane value = 0.75 and NO's is 105? |
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Definition
| A relatively small concentration of halothane (and other halogenated hydrocarbon anesthetics = isoflurane and desflurane) is required to produce MAC. |
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Term
| Can you achieve 1 MAC with NO? |
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Definition
|
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Term
| What determines the depth of anesthesia? |
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Definition
| heart rate, blood presure |
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Term
| What is key for an anesthetic to fuction? |
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Definition
| the A must reach the brain ins an adequare blood-borne concentration |
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Term
| What is the amount of the A reaching an organ a function of? |
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Definition
| the concentration in the blood and percent cardiac output |
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Term
| Which organs equillibriate faster? |
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Definition
| Those with higher blood flows (brain and heart) vus those with lower blood blow (fat) |
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Term
| Why is the net uptake slowed? |
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Definition
| As venous blood containing the A returns to the lung, the partial pressure between the lung and blood decreases, which slows the net uptake of A into the body, and body equill occurs |
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Term
| What does the rate of uptake depend on? |
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Definition
| the rate of deliv of anesthetic gas to the lungs (a combo of % concentration and minute ventilation) |
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Term
| WHY do soluable agents require a slower induction? |
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Definition
| more molecules must be transferred to acheive equill. This takes more time, and slows induction |
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Term
| Why does high cardiac output mean slower induction? |
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Definition
| more molecules are being removed from the pulm circulation per unit of time--slowing equil--and thus induction |
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Term
| What does low cardia output state mean? |
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Definition
| rapid equil, abrupt inductions. Imortant for unconsciousness, and side effects like hypotension |
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Term
| Why will it take longer to acheive awareness than it took to achieve surgical A? |
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Definition
| BC at the beginning, higher than nec concertations can be used to speed the uptake and induction. At the end, lower than zero isn't possible--so kinetics are tied to a smaller gradient |
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Term
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Definition
| ALl decrease BP in a concentratoin dependant fashion. |
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Term
| What effects on metabolism and body Oxygen consumption> |
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Definition
|
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Term
| What MAC signals the beginning of unconsciousness? |
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Definition
|
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Term
| What happens to the uterus? |
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Definition
it is affected by potent agents, but NOT NO.
there is a decrease in uterine blood flow, and a decrease in uterine smooth muscle contractility |
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Term
| How does elimination mostly occur? |
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Definition
|
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Term
| Where are most of the A drugs metabolized? what is the 1 expeption? |
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Definition
| in the liver, via mixed fuction oxidase (P 450) enzymes. NO is only exception. |
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Term
| What is liver tox associated with |
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Definition
| halogenated hydrocarbon admin (so hepititis!) |
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Term
| What are major side effects of Anesth? |
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Definition
| liver tox, neurotox, malig hyperpyrexia, immunospurresion, teratogenesis |
|
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Term
| what is malignant hyperpyrexia |
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Definition
| triggered by inhalent anesthetics, it is characterized by rapid temp elevation, tachycardia, arrythmias, cyanonsis, muscle rigidity |
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Term
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Definition
| it's clinically defined as a state where no movement occurs in response to what should be painful. |
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