Anesthesiology resident Max Feinstein, MD, discusses common medications used in anesthesia and their effects.

Following is a transcript:

Feinstein: Anesthesiologists sometimes tell patients that they are getting a "cocktail" of medications prior to their procedure, which can sound mysterious and intriguing, when in reality this cocktail is typically just comprised of a single medication called midazolam.

My name is Max Feinstein and I'm an anesthesiologist filming here at the Mount Sinai Hospital in New York City and in this video I demystify the medications that are administered to patients prior to procedures. If you find this video interesting or helpful, I'd really appreciate it if you liked it and subscribe to the channel. Let's dive in.

Before we get too far, just a quick reminder that this video does not contain medical advice; it's just a YouTube video. If you need medical advice, you should talk to your doctor.

Midazolam has several very important properties, which are why anesthesiologists use it. The first of those properties is anxiolysis, which is just a way of saying that it can reduce a person's anxiety. This is, of course, very helpful coming into the operating room if a person is nervous about getting surgery, which is very often the case for understandable reasons.

Another useful property of midazolam is that it can cause anterograde amnesia, meaning that patients won't remember anything after they have received the medication. There is an important distinction between anterograde amnesia, which means not remembering something after the medication has been administered, versus retrograde amnesia, which means not remembering something prior to the medication being administered. Midazolam only causes anterograde amnesia, and even then it doesn't necessarily cause amnesia in all patients. It can depend on the dose of medication that's given as well as patient factors like how much they weigh and whether they consume alcohol, which can have cross-tolerance with midazolam.

Midazolam can be used as a primary anesthetic in cases of light or moderate sedation where the goal is to have the patient still conscious and breathing on their own, but just very relaxed. Midazolam is also used frequently as a precursor to general anesthesia where a patient is completely unconscious and not aware of anything that's going on at all. The amount of midazolam that would need to be administered to produce a depth of general anesthesia is impractical in most cases, and so for that reason when patients do receive general anesthesia, there are other agents that are used such as propofol and sevoflurane.

In a small number of cases, there are other medications that can be administered either in lieu of or in conjunction with midazolam. One of those medications that anesthesiologists sometimes reach for is an opioid called fentanyl, which is also short-acting. Generally speaking, anesthesiologists like to reach for short-acting medications because that can help us maintain fine control over physiologic parameters like heart rate, blood pressure, and respiratory status.

When we do include fentanyl as part of the anesthesia cocktail, that's typically because the patient might be in pain and that might be the reason that they are coming in for surgery, for example, if they broke a bone. Anesthesiologists do have to use caution when mixing midazolam with opioids because together those can cause significant amount of respiratory suppression. If the plan is for the patient to undergo general anesthesia, where they're going to be intubated and mechanically ventilated, then respiratory suppression is kind of a moot point, but it is very important for patients to be able to breathe on their own in the time period immediately prior to undergoing general anesthesia.

Another medication that can be used as part of the anesthesia cocktail is a very low dose of propofol, which when given in 10 or 20 mg increments, won't produce general anesthesia in an adult but will actually just produce anxiolysis and perhaps a bit of amnesia. Having said that, propofol can irritate the vein where it's injected, which can be a reason to avoid giving more propofol to an awake patient than they need.

When I mentioned that midazolam is fast-acting, I mean onset can be 2 minutes or less when given through the IV. It typically won't last for more than an hour, although again that also varies depending on the patient. For adult patients, midazolam is typically administered through an IV, which is placed of course while the patient is completely awake. But for pediatric patients who won't tolerate having an IV placed while they are awake, then we can actually administer an oral form of midazolam, but it has a longer time of onset closer to around 20 minutes or so, again depending on the dose and the patient.

One of the common misconceptions around the anesthesia cocktail is that it's a sort of truth serum that causes patients to just blurt out their deepest darkest secrets. In reality, midazolam typically just causes patients to feel relaxed, chill out, maybe giggle a little bit about things that otherwise aren't that funny, and only extremely rarely do patients become disinhibited enough to start saying things that perhaps they wouldn't have said prior to receiving midazolam.

David: I... I feel funny. Is this going to be forever?

Feinstein: But honestly, I have never had a patient actually disclose anything really that embarrassing while they have been under the effects of midazolam or any other anesthetic agent. It's pretty uncommon.

I mentioned that some patients don't remember much, or anything, after they receive midazolam and I think it's really important for anesthesiologists to make patients understand that that may or may not happen once the medication goes in. Expectation setting is a really important part of the patient experience after all.

By the same token, I think it's very important for anesthesiologists to tell patients when they are receiving midazolam or any other medication that's going to change the way that they feel. I don't think it's really fair to surprise patients with medications through their IV without first telling them that they are about to get something that will change the way they feel. While the vast majority of patients who receive midazolam will feel pretty chilled out, there is a small proportion of patients who have what's called a paradoxical reaction where they become hyper-energetic after receiving the medication.

David's Dad: Stay in your seat.

David: [OUTBURST]

Feinstein: If you're a patient watching this video and you're wondering will you receive midazolam or any other medication as part of the anesthesia cocktail before your procedure, the answer is it depends.

Certain aspects of anesthesia practice can vary pretty considerably depending on factors like who your anesthesiologist is, what procedure you're coming in for, what medications and monitoring are available for patients prior to going into the operating room, and so forth. For these reasons, it wouldn't be surprising to me to know that a patient who is coming in for, say, a laparoscopic appendectomy at a certain hospital would probably not be offered midazolam unless there were extenuating circumstances. Whereas a different hospital that has different practice norms would routinely offer midazolam to patients who are coming in for the same procedure.

I do think this variation in practice begs an important philosophical question about the involvement that patients have with regard to the specific medications that they get for their anesthesia and also the extent to which anesthesiologists are involving patients in the decision about what medications will be administered.

On the one hand, I think there is a lot of benefit for anesthesiologists and their patients to have an open conversation about what medications will be administered and why, but then on the other hand that's also not entirely feasible, especially if a patient is under general anesthesia. And there is also an argument to be made for the fact that it can be overwhelming for patients to have to make medical decisions about the specifics of exactly what they are receiving as part of their anesthetic plan that might overall make the experience more anxiety-inducing than it needs to be, as opposed to simply leaving the decisions to the anesthesiologist about how best to produce the outcome that the patient desires, for example, feeling relaxed or being completely unconscious for a procedure.

If you are a patient and you do have any questions or concerns about any part of your anesthesia plan, then it's important to bring it up with your own physician before you undergo your procedure.

Max Feinstein, MD, is a PGY-4 anesthesiology resident at the Mount Sinai Hospital in New York City, where he is also chief resident of teaching. His YouTube channel focuses on perioperative medicine, especially the role of the anesthesiologist.

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What Exactly Is an Anesthesia 'Cocktail'? - Medpage Today