Pharm 1 - Inhalant Anesthetics


Basics
Question | Answer |
---|---|
What drugs do you need to use in combination w/ inhalant anesthetics? | None, they are complete anesthetics (relax mm, analgesia, anesthesia) |
Where are inhalant anesthetics metabolized? | In the LUNGS |
How do inhalant anesthetics cause anesthesia? | Disrupt the transfer of ions (disrupt conduction of nervous signals) |
How safe are inhalant anesthetics? | Low margin of safety, but machines allow us to control this well |
Which inhalant anesthetics can cause a seizure? | Enflurane, Sevoflurane (SEizurEN) |
How would you describe the molecules of inhalant anesthetics? | Small & lipid soluble |
Would you use inhalant anesthetics w/ head trauma? | NO, they ↑ IC pressure* |
Which inhalant anesthetics can help treat seizures? | Iso, Des, Sevo (Sevo can also cause...weird) (ISO DESpise SEizures) |
Which drug most commonly causes malignant hyperthermia? | Halothane |
How (which) do inhalant anesthetics affect pigs? | Halothane can cause malignant hyperthermia in pigs, avoid |
What is the basic path of inhalant anesthetics? | Lung → Blood → Brain → Blood → Lung |
Concentration of _________ governs effects in brain | Arterial blood conc. |
What is the route into the body? Out? | Lungs for both |
What is the partition coefficient? | Ratio of the concentration of the agent in 2 phases at equilibrium. 2 kinds we use: blood:gas & oil:gas |
What does the blood:gas partition coefficient determine? | The RATE (speed) (think of speed of blood flowing) |
What does the oil:gas partition coefficient determine? | The POTENCY of the drug |
Name the 7 drugs in order from slowest to fastest (putting animal to sleep? recover rate? same scale as B:G? so confused) | Ether, Halothane, Enflurane, Isoflurane, Sevoflurane, Nitrous oxide, Desflurane |
What drug is the best for heart & the worst for lungs? | Desflurane (my heart is Desperate for you, but my lungs just can't breath) |
Mnemonic to the order of drugs slowest to fastest? | Every Halloween Everyone Is Scared N' Disguised |
Which drugs are the heart-friendliest ones? | Isoflurane & Desflurane (Iso des-parate for your heart) |
If you have a ↑ blood:gas ratio, what does that mean for speed? | SLOW. |
If B:G ratio is ↑, what does it mean for solubility? Speed? | ↑ BG means ↑ solubility means ↓ speed (↑ solubility means it dissolve in the blood well, so it converts back into a gas slower) |
If you have a ↓ blood:gas ratio, what does that mean for speed? | Fast (↓ solubility means it doesn't dissolve in the blood well, so it converts back into a gas quicker) |
If you have a ↑ oil:gas ratio, what does this mean for potency? | ↑ potency |
If you have a ↓ oil:gas ratio, what does this mean for potency? | ↓ potency |
If you have ↑ O:G, what does this mean for MAC? Potency? | ↑ O:G = ↓ MAC = ↑ potency |
Ex: if the MAC of Desflurane is 6xs higher than Halothane, what does this mean for potency? | Desflurane is less potent MAC- Minimal Alveolar Concentration |
Respiratory
Question | Answer |
---|---|
How do inhalant anesthetics affect alveolar ventilation? What does this do to the partial pressure of CO2? | They ↓ alveolar ventilation (which is a direct relation to the dose) which ↑ the partial pressure of CO2 |
What does a MAC of 1 mean? | It means successful anesthesia in 50% pts |
What do we use the MAC to measure? | Effectiveness |
What does an ↑ in concentration do to the MAC? | ↑ conc = ↑ mac (if you have to increase conc of the drug, then that means that the minimal alveolar conc of drug needs to be increased as well) |
What does MAC stand for? | Minimum alveolar concentration |
What would you say the MAC tells you? | Effective concentration where it's effective in 50% of the animals |
What does ↑ MAC do to the compensating responses? | ↑ MAC = ↓ compensating responses |
How do inhalant anesthetics affect the bronchi? | Bronchodilation |
Which inhalant anesthetic causes laryngeal spasm (making it hard to intubate)? | Desflurane ("DESent" let you intubate) (Also remember Injectable Anesthetic Barbiturates cause this as well) |
If you ↑ the mac, what happens to the breathing rate? | ↑ mac, ↓ of breathing (give more gas, breathe less) |
Which inhalant anesthetic is the most resp. depressive (rate) | Desflurane (("DESparate for air")?) |
Which inhalant anesthetic causes the highest partial pressure of CO2? What is this related to? | Desflurane, bc it causes the more resp. rate depression (aka ↓ alveolar ventilation) |
What is the "minute volume" | Amount of air inhaled & exhaled in a minute |
↑ MAC does what to the minute volume? | Decreases it....Desflurane is the most severe example of this |
Which inhalant anesthetic causes the highest partial pressure of CO2? The 1 w/ the least affect? | Most = Desflurane. Least = Isoflurane |
Cardiovascular
Question | Answer |
---|---|
If you ↑ the inhalant anesthetic dose, what happens to the CO? Contractility? Stroke volume? | They would all decrease? |
How come there are such pronounced CV affects w/ inhalant anesthetics? | They alter the Ca++ homeostasis |
How do inhalant anesthetics affect the cerebral blood flow? | ↑ cerebral blood flow (↑ IC pressure--- no good for head trauma) |
Where do inhalant anesthetics ↑ blood flow? Dec? | ↑ cerebrum, ↓ liver & kidney |
What is automaticity of the myocardium? How do inhalant anesthetics affect it? | Automaticity = body tries to compensate depressive effects of the inhalant anesthetics. However, although it is INCREASED! it cannot overwhelm the drug effects |
Which inhalant anesthetic causes the steepest decrease in CO? | Halothane (Hal was lazy, had bad output) |
What do inhalant anesthetics do to blood pressure? Resistance? | ↓ BP & resistance |
Which inhalant anesthetics can cause an ↑ in heart rate? | Halothane & Desflurane (esp if the MAC is over 1.5) (my heart races, desparate for you, im in hal) |
Which inhalant anesthetic causes a decrease in splanchnic blood flow? | Halothane (I can think Halothane makes pigs hot to touch bc drew blood away from organs) |
What is the decrease in blood pressure dependent on? | Dose |
Which drugs preserve CO? | Isoflurane & Desflurane (Iso Desparately love your heart) |
Which drug causes the steepest drop in blood pressure? | Desflurane (Des Drop) |
Which drug causes the most severe drop in CO? | Halothane |
Liver & Kidney, Muscles
Question | Answer |
---|---|
Which drug will cause hepatocellular injury? Why? | Halothane, bc it has hepatotoxic metabolites |
How do inhalant anesthetics affect hepatic circulation? | Decreases it |
How do inhalant anesthetics affect renal blood flow? GFR? | ↓ them |
Do inhalant anesthetics provide muscle relaxation? | Yes, some mm relax |
Which drug most commonly causes malignant hyperthermia (a myopathy)? How does this happen? | Halothane, loss of control of Ca++ = muscle rigidity = ↑ metabolism = heat |
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