Pharmacology for Rapid Sequence Intubation (RSI) Airway Management in Trauma Patients
Hello, my name is Laura Celmins. I am a clinical pharmacist here in the emergency department at the University of Chicago Medical Center. I've been here for about two years, and I've been part of the team for all of our critical patients who come into the emergency department, including but not limited to our trauma patients. So I'll also talk to you guys a little bit today about RSI medications as part of our airway management for our trauma patients.
Once the team has made the decision that they're going to intubate the patient, whether it's due to the patient's injuries themselves for pain control, or due to altered mental status, I come in and I have my fantastic RSI kit ready to go. So first things first, we want to assess the patients themselves, look for any obvious contraindications. We'll talk about the contraindications we have for certain medications. We're going to look at the patient's size. If we have any inkling - we won't have labs back usually on a trauma patient - but do we have any reason to suspect this patient may have liver or renal dysfunction? And that will help us decide which medications we choose to use. Part of my job, as well as providing the medications for the initial intubation itself is making sure we have the appropriate analgesic plan, and then the postintubation sedation as well so that we can keep these patients comfortable while we continue with our treatments including imaging and any therapeutics they may need. So once we've decided that we're going to intubate the patient - we've made our plan, we're starting to get our supplies ready, you know, they're getting the laryngoscope, we have RT at the bedside as well.
I'll start and we'll consider what's going to be our induction agent. So an induction agent is given to sedate the patient appropriately so that they can then receive the paralytic that allows the patient to be intubated safely and quickly. When we talk about RSI in the emergency department, that's rapid sequence intubation, that's pretty rapid compared to what we do in the operating room. In the operating room, we have - it's a much more controlled environment, we have more time. The anesthesiologists have the options of using gas agents for induction. So by doing a - with this rapid sequence intubation, we have the patient sedated more quickly, and this is also to improve our chance of first-pass intubation, and also so that we can have decreased side effects such as nausea and vomiting that could cause aspiration down the line. Now our first medication that we'll give will always be the induction agent, like I said, to facilitate us giving the paralytics. At this institution, our first-line agent, kind of our workhorse, is etomidate. So, etomidate is a GABAergic agent. Your dose for that, on a weight-based dose, is 0.3 mg/kg. But for your average adult patient, we tend to give 20 mg. It comes in a 20-mg vial often. And that's going to be kind of our workhorse dose. What's great about etomidate is it's hemodynamically stable, causes very little hypotension compared to some of our other agents, and it works incredibly quickly and reliably. We have an onset within a minute, and we get about 5-10 minutes of duration out of that single dose. There is some controversy for its use in sepsis, but we use it pretty reliably in trauma patients on the regular. Another agent that we sometimes use for induction would be ketamine. So ketamine is kind of a jack of all trades, it's got lots of indications here in the emergency department. When we're using it for RSI, we tend to use a dose of 1-2 mg/kg. We're going to give that as a slow IV push, which can be hard to do sometimes in a stressful situation. But what to remember about ketamine and adverse effects is that it can cause tachycardia and hypertension, so if you have a patient who is already tachycardic or hypertensive, that may not be our drug of choice. So we give those agents first, and we want to give them a chance to work to ensure that the patient is appropriately sedated prior to us giving our paralytic agent.
As far as our paralytics, our workhorse is our depolarizing agent, succinylcholine. So succinylcholine we dose at 1.0-1.5 mg/kg, again given IV push. So for many of our adult patients, they're going to fall into the 100-120 mg dose range. Now as far as contraindications to succinylcholine, patients who, you know, maybe won't get this medication, we have to think about some structural/functional muscle diseases because it is a depolarizing agent, so you do have patients who are more sensitive to it if they have myasthenia gravis, muscular dystrophy, etc. We also worry about - it can cause a brief hyperkalemia, so you can see an increase in potassium of about 0.5 mEq/L. That is transient in a patient with normal kidney function, but if you have a renal patient come in, and if we don't know anything about their dialysis history, we don't have labs back, we may very well want to withhold this and give a different agent. So the onset is less than 60 seconds. Like I said, we dose it at 1.0-1.5 mg/kg. And we get also about 5-10 minutes of paralysis. Just like the same duration as your etomidate and that's really important to remember down the line - that you want to make sure that you have a patient who is adequately sedated while they're paralyzed. Now if we have a patient who succinylcholine isn't our best choice, and maybe we see that they have a dialysis catheter, we have a history that they've missed dialysis, we would want to use a different agent. So what we use here is rocuronium as our non-depolarizing agent The dose here would be 1.0-1.2 mg/kg. You're usually pretty - in a good place to just go with 1 mg/kg. Your onset is also going to be in the 60-90 seconds, but your duration is going to be much longer. So your looking at a duration of paralysis of 30-60 minutes depending on the dose you gave, and if the patient has any underlying clearance issues, they hold onto it longer. And that's where it really comes in, and is very important that our postintubation sedation analgesia is curated to what our sedation and what our paralytic regimen was. So we've given the medications. We're going to give, you know, our induction agent, give our paralytic.
While the team is actually doing the intubation, I'm going to be on the background, making sure that we have IV pumps, the appropriate equipment available. What we usually do is analgo-based sedation, so we'll often start with a fentanyl drip. But then we'll also want a sedative agent, so in this case we have propofol. Again, especially in our trauma patients, we want to be careful - you don't necessarily want to make them hypotensive. But, depending on what their mental status was prior to requiring intubation, we may need to add that medication.
If you do have a patient who becomes hypotensive prior to intubation, we have a couple different options available to us. Sometimes we like to use push-dose pressors. In this case we have phenylephrine available. So we would do this prior to the actual intubation, usually during the preoxygenation phase. And this will allow us to transiently increase the patient's blood pressure while we're providing an airway for them. If you don't have push-dose pressors available - we're fortunate enough to have continuous infusion vasopressors as well. So we have norepinephrine readily available, it's kind of our workhorse as far as our continuous vasopressors go. So, I don't have here to show you fentanyl, but that is kind of our workhorse for analgesics. We can use it for push-doses. We can also give it as a continuous infusion, and we prefer that in our patients who've been intubated so that while you're continuously reassessing, you're not also having to go to the Omnicell or the Pyxis and get more medication for the patients.