[MmacFN]

OK


So i have read a little about the different gasses used in the Anes. profession. It seems the most common are nitrous oxide, sevoflurane, desflurane, isoflurane and halothane.

I understand some of the ins and outs such as sevoflurane and halothane are easy to inhale while desflurane is very irritating to inhale and has a shorter duration of action. If a very short-acting anesthetic is needed, the anesthesiologist can switch to desflurane after you fall asleep. Nitrous oxide is easy to inhale, but when used alone is not potent enough to be a complete general anesthetic. However, it can be used alone for sedation, or combined with one of the other inhaled anesthetics or injected liquid anesthetics for general anesthesia.

They all seem to have some interesting properties. For example:

- halothane may cause the heart rate to slow down and the blood pressure to decrease while desflurane may cause the heart rate to speed up and the blood pressure to increase.



It seems an important property of anesthetics is reversibility. If i understand it correctly, once the anesthetic gas is turned off, the blood stream brings the gas back to the lungs where it is eliminated. The more soluble the gas is in blood, the longer it takes to eliminate. Nitrous oxide and desflurane are the shortest-acting anesthetic gases because they are the least soluble in blood.

So I guess where Im a little confused is why it wouldnt be equally as good to use diprivan or vecc and a versed drip etc etc. All those combinations that are commonly used. What advantages does utilizing a gas machine and the various gasses have over those other drugs?

[versatile_kat]

Originally Posted by MmacFN

So I guess where Im a little confused is why it wouldnt be equally as good to use diprivan or vecc and a versed drip etc etc. All those combinations that are commonly used. What advantages does utilizing a gas machine and the various gasses have over those other drugs?

Titratability (depending on the gas), hemodynamic stability, amnesia, analgesia, and muscle relaxation. But, once you start school, you'll see that anesthesia can be delivered a million different ways.

And unless you end up in a rural hospital or doing missionary trips, you'll rarely see halothane.

[EmeraldNYL]

First of all, versed hangs around forever, so if you want your patient to wake up in a resonable time frame to be extubated when the surgery is over, this is a really bad idea. Especially in older patients, it takes forever to clear. I don't routinely even give Versed in a case that I know will be short as a pre-med unless the patient is anxious. Propofol gtts are frequently used as total anesthetics, in a technique called TIVA (total IV anesthesia). You might use this, for instance, if your patient has a history of malignant hyperthermia. Don't forget that Propofol also has its drawbacks-- I have seen it cause profound hypotension. It can also cause bradycardia, and I have seen people develop rashes after induction from histamine release.

[MmacFN]

Hey

Makes sense.

I have seen hypotension with diprivan and versed. Ive had a couple of rashes which i gave 12.5 of benedryl iv for and thats seemed to solved the problem.

So it appears to me it may simply be choices depending on the clinical circumstances of the surgery? Pretty straight forward.

Originally Posted by EmeraldNYL

First of all, versed hangs around forever, so if you want your patient to wake up in a resonable time frame to be extubated when the surgery is over, this is a really bad idea. Especially in older patients, it takes forever to clear. I don't routinely even give Versed in a case that I know will be short as a pre-med unless the patient is anxious. Propofol gtts are frequently used as total anesthetics, in a technique called TIVA (total IV anesthesia). You might use this, for instance, if your patient has a history of malignant hyperthermia. Don't forget that Propofol also has its drawbacks-- I have seen it cause profound hypotension. It can also cause bradycardia, and I have seen people develop rashes after induction from histamine release.

[Pete495]

Halothane isn't used much anymore, and will probably go by the waste side someday soon. It has some more side effects than the others and a high blood gas solubility, so it isn't eliminated very quick. the only thing keeping it on the market is its cheapness.

You can not get the anesthesia with a propofol drip that you will get with an anesthetic gas. You will understand when you get into the OR. Although, there are cases where you will not run any gas, this is generally not a good idea. It takes a lot of propofol to make somebody not move, and requires increased doses all the time. Inhalational agents above all provide excellent muscle relaxation, and this is half the point of using them. You will find you will have to run your agent at a certain % to prevent patients from moving. and as the previous poster mentioned, they provide other properties as well. In my facility, n2o is used very little anymore. the docs don't like it, and my limited experience with it hasn't made me want to use it a lot.

The old addage that versed hangs around a long time is a confusing one. I tend to think the dose is more individualized. Had a patient who got about 8mg of versed the other day and was still awake during a MAC case, and she had a cardiac history, nor was she very large, or a drinker. had to give her propofol to keep her down. most of our patients get 2mg preop, and this is just enough to keep them happy. I haven't found that I've had trouble waking some of them up. Personally, right now, I don't think versed hangs around as much as the books say it does, but that is just in my limited experience.

The clinical circumstanes are not straight forward at all in my opinion. Every patient is different, and there is always one thing you should do with one patient, that you shouldn't do with another. for instance, you wouldn't mix lidocaine w/ propofol on a cardiversion, since it is an antiarrhymic also. but we mix the lido with the diprivan on almost everyone to prevent burning. although, in another thread, it says not to do this, it is a pretty common practice you will find.

[MmacFN]

Excellent post

My experience with versed has been drastically different with each patient. I dont prefer the drug and use it seldom when i need sedation.

I do understand that clincial circumstances arent always straight forward. What i mean is that here dont appear to be any obvious issues with one gas or another based upon the info i read and posted here.

good info

Originally Posted by Pete495

Halothane isn't used much anymore, and will probably go by the waste side someday soon. It has some more side effects than the others and a high blood gas solubility, so it isn't eliminated very quick. the only thing keeping it on the market is its cheapness.

You can not get the anesthesia with a propofol drip that you will get with an anesthetic gas. You will understand when you get into the OR. Although, there are cases where you will not run any gas, this is generally not a good idea. It takes a lot of propofol to make somebody not move, and requires increased doses all the time. Inhalational agents above all provide excellent muscle relaxation, and this is half the point of using them. You will find you will have to run your agent at a certain % to prevent patients from moving. and as the previous poster mentioned, they provide other properties as well. In my facility, n2o is used very little anymore. the docs don't like it, and my limited experience with it hasn't made me want to use it a lot.

The old addage that versed hangs around a long time is a confusing one. I tend to think the dose is more individualized. Had a patient who got about 8mg of versed the other day and was still awake during a MAC case, and she had a cardiac history, nor was she very large, or a drinker. had to give her propofol to keep her down. most of our patients get 2mg preop, and this is just enough to keep them happy. I haven't found that I've had trouble waking some of them up. Personally, right now, I don't think versed hangs around as much as the books say it does, but that is just in my limited experience.

The clinical circumstanes are not straight forward at all in my opinion. Every patient is different, and there is always one thing you should do with one patient, that you shouldn't do with another. for instance, you wouldn't mix lidocaine w/ propofol on a cardiversion, since it is an antiarrhymic also. but we mix the lido with the diprivan on almost everyone to prevent burning. although, in another thread, it says not to do this, it is a pretty common practice you will find.

[Pete495]

As far as gas goes, you are right and you are wrong. There are instances when you will use one gas over another, such as renal patients, but then again, a lot of what you use depends on availability. some facilities carry only 2 or 3 gases. the main ones in use are des, iso, and sevo. my facility only has sevo and iso. kind of sucks. I'd love to be able to use des, but it is expensive I think. they will be coming out with another one soon, which will be a generic of sevo, cuz sevo's patent runs out soon. so we'll see what they come up with. hopefully it is something good.

[MmacFN]

ahhh


interesting stuff.

Im excited to get more into the mechanics of it all!

[athomas91]

it all comes down to $$$$$$$
never forget it...

propofol/remi drip - great anesthetic - expensive as all get out...
des on a short case - great - longer than 20 min - your MAC of 6 will eat through the company pockets...

gases provide amnesia, skeletal muscle relaxation - some have bronchodilatory effects (sevo) and have even been used to break status asthmaticus - the only thing they don't provide is analgesia...

none of the other meds on their own provides such benefits as the gases.

[Nitecap]

Originally Posted by athomas91

it all comes down to $$$$$$$
never forget it...

propofol/remi drip - great anesthetic - expensive as all get out...
des on a short case - great - longer than 20 min - your MAC of 6 will eat through the company pockets...

gases provide amnesia, skeletal muscle relaxation - some have bronchodilatory effects (sevo) and have even been used to break status asthmaticus - the only thing they don't provide is analgesia...

none of the other meds on their own provides such benefits as the gases.

Actually all halogenated agents can bronchodilate. Sevo is used for inhaled induction b/c it lacks the pungent odor that Iso and Des has (smells like ether) It is the odor of these that cause coughing and upper airway irritation which can lead to bronchospasm. However if the tub is in and you are running Des of Iso and the pt is asleep all the halogenated agents cause bronchodilation.