isoflurane

anonymous asked:

Can you explain a few different types of sedatives? I know ketamine is your favorite, but what are some other options?

Hey there nonny! Congrats on being the first in the inbox for July!! 

Okay. Sedatives. This is an entire monumental class of medications, so you’ll forgive me if I have to be fairly brief about each type. 

There are more than a few sedatives and anesthetics that have been used throughout history. In this day and age, the most common are the benzodiazepines, which I have  [a full post on here]. 

Basically, benzos work by hitting GABA receptors and suppressing brain activity, which is also why they work so well for seizures. Benzos can be given as an injection in the muscle (IM), in the vein (IV), orally (PO), and some can be given via the nose (IN, intranasally). How long they take to kick in will depend on the medication. 

In terms of anesthetics, the next big one is propofol, AKA Milk of Amnesia, AKA Jackson Juice if your character is a bit of a cynic. Propofol is a milky-white medicine which MUST be given by IV. Propofol is basically instant unconsciousness in a glass vial. Anesthesiologists love this crap, because it’s literally dial-a-brain: turn on the medicine and the brain shuts down, turn off the medicine the person wakes up with minimal effects. Having had propofol, I can say it’s absolutely magical. Outpatient procedures basically depend on it. 

The downside of propofol is that it can cause severe drops in blood pressure, which makes it less than ideal for emergency uses, and that it must go by IV. 

Next up are the barbiturates, such as phenobarbital, thiopental, and secobarbital. These are an older class of meds who have fallen out of favor as sedatives but retain a role for seizure prevention and management, and were initially investigated as potential [truth serums]. 

These tend to be fairly long-acting and relatively unpredictable in their effects (compared to benzos and propofol), and can be given as pills (PO), intravenously (IV) or in the muscle (IM), depending on the specific med. These last anywhere from 4-6 hours, and can cause respiratory depression in overdose (just like almost all benzos). 

Sleep aids like Ambien (zolpidem) technically fall into the sedative category as well. Diphenhydramine is typically sold over-the-counter as a sleep aid… but is better known by its trade name, Benadryl. It’s sold OTC in the same doses for both indications but often at wildly different prices, so a smart character might take the same med for both indications, while a less-observant character might accidentally overdose if they take it for their allergies (Benadryl) and to help them sleep (Unisom). 

As for inhaled sedation, ether and chloroform are both historical inhaled anesthetics, but the difficulty with them is dosing. Both drugs have a fairly narrow therapeutic index; that is, the difference between a dose that’s safe and healthy and a dose that could kill your character is very small. They both also take a few minutes to kick in, meaning that the old ”Hey, does this smell like chloroform to you?” method of subduing characters isn’t realistic. 

In fact, all sedatives take between 1 and 5 minutes to kick in, meaning  that your character may still have to struggle with the subdued before the meds kick in. 

Nitrous oxide is another inhaled anesthetic, AKA laughing gas, with a sweet odor. Its half-life is about 5 minutes, so characters who need to remain sedated will need the nitrous to continue to be on. It typically doesn’t produce general anesthesia, but is used as an anxiolytic (ie to reduce anxiety) and for partial sedation. Interestingly enough, some ambulances in this world carry nitrous oxide. (Note: not to be confused with inhaled nitric oxide, which is a pulmonary antihypertensive gas.)  

Other anesthetic gasses still in use include desflurane, isoflurane, and sevoflurane. These require an anesthesia machine to deliver, partially because many of them are liquid at room temperature and must be heated to become gasses. 

Etomidate is an anesthetic that’s used almost exclusively for intubation; it must go IV, it only works for a few minutes, which means it needs another sedative to go with it. That makes it ideal for putting tubes in people. 

I’ve struggled with whether or not to include opiates in this list. The thing about opiates, such as morphine, methadone, meperidine, and heroin, is that while they do make characters sleepy, it’s not their primary effect. (Then again, doctors don’t always get this right; you would be appalled by the number of ICUs who believe that using fentanyl as a “sedative” is an appropriate course of action.) These work by acting on opioid receptors, which manage pain but also help make someone very drowsy. The danger with opioid overdose is respiratory depression, to one degree or another. 

You mentioned ketamine. Ketamine is the anesthetic I think works best in most situations in which writers use sedatives; it reliably produces unconsciousness, it’s relatively safe when administered properly, doesn’t tank blood pressure, typically leaves breathing reflexes intact, etc. However, it’s not perfect, and it’s a bad idea to use recreationally, as is literally every drug in this post. 

I hope this helped!! 

xoxo, Aunt Scripty

disclaimer    

This blog is proudly sponsored by generous Patrons. Have you considered sponsoring the blog?

Ebook for Free! 10 BS “Medical” Tropes that Need to Die TODAY!  

Important tech things to remember in veterinary medicine

1. Cats have four sets of claws. All four sets hurt like a mother.
2. Doctors will steal your pen. Hunt them down and steal it back.
3. Chihuahuas are demons disguised in sweet little packages.
4. Brachycephalic dogs can still bite. Even with those cute smooshed in faces.
5. Hitching up your scrub pants in front of a client is preferable to mooning a client.
6. A quiet child is a helpful child in an exam room. Even better if they are sleeping.
7. Pugs are impossible to restrain.
8. Cursing in front of clients, while cathartic, is frowned upon.
9. Dogs awaiting procedures will happily poop all over their kennel and dance in it…just as you’re getting them out to pre-med.
10. They will also do this five minutes before their owners pick them up.
11. Drink plenty of water..even though this will cause you to have to pee ten minutes into surgery.
12. A diabetic animal’s urine is sticky. If you step in it you will make that funny squishing sound everywhere you walk.
13. Nothing says love like cleaning dog vomit out of another tech’s hair.
14. The scavenger is your friend. Unless you like passing out from isoflurane….whatever floats your boat.
15. Video taping an abscess procedure is educational…right? For science?

2

isoflurane- inhaled anasthesia

flumazenil- used to treat benzodiazepine overdose, known to antagonize sedation

rohypnol- intermediate acting benzodiazepine

midazolam- benzodiazepine used for lethal injections in the US

pentobarbital- benzodiazepine that leads to respiratory arrest in high doses; used for executions in the US

Ava and Odin escaped a kill house; drugs outside the dumpsters of the building.

Hey kids, let's play guess the smell

Your choices are:
1. Anal glands
2. Giardia laden fecal sample
3. Parvo
4. Vomit
5. Electrocautery
6. A recently drilled tooth
7. Isoflurane
8. Skunk
9. An abscess
10. A maggot riddled wound
11. Diabetic urine
12. Kidney failure breath
13. Dental disease breath
14. Cat urine
15. Heat fixed urine sample
16. All of the above

Just to confirm, all of the drugs that were more clearly visible in the last update (isoflurane, rophypnol, midazolam) are heavy duty sedatives, anesthetics and muscle relaxants, mostly used for surgery. And the one Ava’s holding, Pentobarbital, causes respiratory arrest in high doses and more infamously has been the primary substance in the “lethal injection” used by the more modern US executions.

How Anesthesia Works In Animals

There are basically two types of anesthetics: injectable anesthetics and gas anesthetics.  We at All Pets Veterinary Home Care use gas anesthesia nearly exclusively for our patients as they are typically both more consistent and safer than their injectable counterparts.  This means our patients and their owners can enjoy less risk & more comfort.

When an injectable anesthetic or sedative is injected into a patient, there is no way of getting it out once it’s in.  If the patient proves sensitive or allergic to the drug, we must simply do what we can to support them until the effects wear off.  Even in the rare case that there is an antidote to the drug, there is no guarantee that the patient will respond as desired or that we will be able to act fast enough for the patient to benefit from the antidote’s effects.  Of course, sometimes injectable anesthetics & sedatives are the best choice and in those cases we must simply be as cautious and prepared as possible in order to prevent and, if needed, handle any problems that may occur.

In those cases in which injectable drugs are not needed, we use isoflurane gas anesthesia.  This is a newer and much safer cousin to the ether gas used in the old days.  Isoflurane gas actually starts off as a liquid which is placed into a special machine called a vaporizer, turned into a gas and mixed with oxygen prior to being administered to a patient.  As the mixture of oxygen and isoflurane gas is breathed in by the patient, it is absorbed into the bloodstream through the lungs and travels to the brain where it does its work to place the patient into an anesthetic state.  The beauty of gas anesthesia is it works very quickly.  This not only means patients reach an anesthetic plane quickly but it also means that they can be woken up very quickly as well, either when the procedure being performed is complete OR if there is a problem of any kind during the procedure.  This is due to the fact that not only is the gas anesthesia delivered to the brain through the lungs but it also exits the body through the lungs.  This means that as soon as the anesthesia machine is turned OFF and no more anesthetic is being breathed IN, the patient begins breathing OUT all of the anesthesia that they have in their body.  With each and every breath, the patient has less and less anesthetic in their body and begins to wake up very quickly. 

This ability to control the anesthesia so precisely by using gas means there are less chances for complications to arise.  Contrast this with the injectable forms which often leave doctors and/or technicians sitting with patients for variable periods of time after a procedure while waiting for the anesthetic to wear off and your choice of anesthetic should be clear the next time your pet requires anesthesia! 

NOTE:  Of course, these statements are very general and, as everyone knows, we must be specific when dealing with the life of a patient.  No topic in medicine is black & white and it is the grey areas we must account for when formulating any diagnostic or treatment plan.  Therefore, every precaution must be taken and every complication must be ready to be dealt with should one occur at any time.  Only then can we be certain that we are doing what is best for our patients.

Ollie is a Survivor (but not a smart one!)

I had a pretty traumatic experience with Ollie on Thursday evening. I was flying him down the road from the house I’m staying at, when he saw a bug flying back towards the house and took chase. He ended up on the roof of the house. That’s when he noticed the large gyr-prairie hybrid falcon perched out in a chain-link weathering area in the back. He saw a tuft of feathers (left-over food) on the bird’s feet and decided to take it from her. He flew THROUGH the chain link and tried to grab the large falcon’s feet. Needless to say, it did not end well for him. 

The falcon grabbed him and I went full mama bear. I got in there within seconds and pried the falcon’s talons off of him (she had one foot around his neck and the other around his abdomen). I carried him into the house with him alarm calling the whole way. When I got into my room, I checked for punctures but couldn’t find any. I noticed that his leg was held out funny and he couldn’t walk well. My biggest fear was internal damage. A punctured lung or internal bleeding would be the end for him. I tried calling around to all the local vets but it was 6pm and none of them had after-hour avian vets on staff. So I had to wait until morning to take him in. 

The next day I took him in and the vet did an exam. He was also unable to find any punctures on him, but prescribed antibiotics just in case. He could not feel any broken bones or dislocations either, but wanted to do an x-ray just in case. The anesthetic they used was isoflurane, one of the gentlest and most commonly used in birds. Still, after just one x-ray, Ollie responded poorly and stopped breathing. They had to insert a breathing tube and manually breathe for him for about ten minutes! His heart never stopped but it beat weakly. Finally, he started breathing again and eventually woke up just fine. 

Due to his reduced function in the lower legs, the vets and I are guessing he has neurological damage in the lower lumbar region. This results in him being unable to properly place his legs, so he is off-balance and has trouble perching. The way he walks looks like he’s drunk - stumbling and wobbling. One leg is definitely worse than the other. The vet says his chances of recovering are fair, but not guaranteed. He prescribed anti-inflammatories as well to help with pain and swelling. 

I now have Ollie in a small crate with cardboard on the inside of the door and mesh covering the side windows. It will restrict his motion, hopefully without damaging feathers. I have a piece of rug on the inside and made a nest for him out of a towel rolled up and shaped into a donut (a technique I learned from the wildlife rehabilitation center). He seems to really enjoy the “donut” and spends most of his time sitting in it, resting. Besides that, he still acts like himself. When I open the door, he comes out to sit with me. He takes food well and doesn’t seem to be in pain.

I take him out for a few short sessions each day to observe his progress, feed him, and maintain our relationship. Tonight he was able to perch better on my hand (not leaning as much or dangling a leg) and even managed a short flight! So it looks like he is slowly recovering. I was really excited to see him fly because it means his wings are still functional. He may never be 100% again, but I at least want him to be able to fly and perch, and his chances are looking pretty good! If he’s really lucky, he’ll regain full or nearly full function of his legs after a few weeks of rest. Nothing I can do now but keep him rested, give his medications daily, and wait and see. 

Either way, he’s one lucky bird (though not the smartest)! He took on a very large raptor and is lucky to have come out of it alive. Hopefully he learned a valuable lesson too - big birds are dangerous! I never thought he would so blatantly challenge a larger falcon like that, especially from such a distance (I made sure to get what I believed to be a safe distance away before flying him), but now that I know how reckless he is, I’ll be sure to keep him far far away from any other birds in the future. I guess I raised him to be a little too bold