Thank you, everyone. All right. Here's my disclosures. Tony already kind of talked about them. So I'm going to, for interest of time, I'm going to pull forward some of the latest studies on this. But we have a short amount of time, so I'm going to just kind of roll through this pretty quickly. So really, with ICU liberation and getting patients off of vents, we're really just looking at how quickly can we do that? When is it safe to do it? We want to make sure that there's reasonable resolution to the assault or what put them on the vent to begin with, and whether or not they can sustain spontaneous breathing and adequate gas exchange. So there's really a three-step process, and I'm going to run through these three steps. And then I'm going to talk a little bit at the end about clinical practice guidelines. So readiness to wean is where we're going to start. So there's really three parts to that. Part of it's subjective. So do you have an adequate cough? Are we on neuromuscular blockades? You can see that information. There's objective. Where's their heart rate? Where's their hemoglobin? What's their blood pressure? And then it's really about looking at the adequate oxygenation and testing. We're going to talk about this a little bit more, but inspiratory capacity. Where's their tidal volume when they're spontaneously breathing? What's their RSBI? There's lots to that. So we're going to kind of go through this in a little bit deeper dive. So you've looked at the patient, and you know that they're ready to wean. But the actual act of liberation is a little bit different. There's lots of tools that we use. And I'm going to tell you right now, from the beginning, there's not one evidence-based way of doing this. There's a lot of different tools that are available. There's a lot of studies that have been published. I'm going to toot a respiratory therapist, because just this year, December of 2023, Carson Roberts actually took a look at this and did a urine review in respiratory care about ventilator liberation, and where are the studies at related to that. So I'm going to quote him a lot in this, but I want you guys to know you can go out and take a look at that yourself. But really, part of this is the spontaneous breathing trial itself. And that encompasses pressure support trials, TPS trials, rapid shallow breathing indexes. Some people are using the automatic tube compensation. There's lung ultrasound and diaphragmatic electrical activity. So I'm going to dive into this a little bit more in depth. Automatic tube compensation, that really, for the newer technology ventilators, it is not a mode, but an option for you to be able to take a look at that. So it's a way to be able to offset possibly the size of the ET tube and the workload that happens, especially if you have an ET tube that's too small. Because if you have an ET tube that's too small, that patient has to work a little bit harder to breathe with that ET tube. So it's a way to kind of do some compensation. And you can see the example here of how that kind of works. So a really great study that was published by Cardinal Fernandez and his group in 2022, they did a systematic review and meta-analysis comparing automatic tube compensation with different modes of ventilator weaning. And they really just wanted to compare it to support modes and what the success was with ATC versus SBT and extubation. So in the SBT group, they had 655 patients. And this is a really busy slide. I know that. I'm just going to kind of walk you through it. But what they basically wanted to take a look at is, if we had ATC and a PEEP less than a certain amount, and they used 7.5, what they found was that was associated with significantly higher probability of a successful SBT compared to TPEs. They also compared just doing pressure support and PEEP, which a lot of us do, compared to TPEs. And then they also wanted to see which intervention had the highest probability. So we're going to kind of go through this. So with extubation, they had 705 patients. They did all the same comparisons to see which is actually more successful. And then same with days on vent, which is more successful. What their conclusion was that ATC could improve the rate of extubation success, but it wasn't necessarily the best in terms of SBT success. So I'll leave that there. You choose what you choose. Spontaneous breathing trials. So there's a couple different questions. What's better? Do we do pressure support, or do we do TPEs? Just for a show of hands, I'm just curious. How many of you just do pressure support? Does anybody do TPEs? Everybody raised their hand, so I'm just checking. OK. I'm not saying it's right or wrong. I'm just going to show you what the evidence says. I think the other big question is, how long? No matter what you do, how long do you do it for, right? So we're going to talk through that too. So this was actually published in 2022, Thiel and the group. They published this in CHEST. They conducted a multicenter, randomized controlled trial to determine the differences between pressure support and TPEs, SBTs, in subjects at high risk of extubation failure. And their definition of high risk, if you were over 65 and you had any underlying chronic cardiac or respiratory disease. So when I looked at that, I'm like, well, that's half the ICU I used to work in. Like, that's pretty much everybody, right? They randomized them. You can see about half the group got pressure support, half the group got TPEs. You can see what they put them on for pressure support levels. You can kind of see that. Their primary outcome was the total time without exposure to invasive ventilation. So basically vent-free days at day 28 after the initial SBT. And then they had some secondary outcomes. And what you can see from the graphs over there, if you look at the different graphs, is between pressure support and TPEs, pressure support's in the green and the TPEs is in the blue. I know it's hard to read in the back. Pretty much among patients who had high risk of extubation failure, SBT with pressure support didn't result on a significantly more vent-free day at 28 days compared to TPEs. So for those of you that raised your hand about TPEs, please raise your hand a little bit higher, because you're not doing anything wrong in this case, right? The outcomes are pretty much the same. And you can see that by the graphs over there. This carried on. Yet in his group in 2023 also conducted one, but the difference in this one is they wanted to compare the amount of time, which I think is really what we're all asking. It probably is not so much which one we do, but how long do we do it for? I know in my practice, if one of my docs would have said, let's put them on a TPEs for 120 minutes, I would have said, let's put you on a TPEs for 120 minutes. And then we'll talk, right? But that, you know, it's whatever. So they compared pressure support at 120 minutes, at 30 minutes, TPEs at 120 and 30 minutes as well. They looked at nine randomized controlled trials of about 3,000 patients. So this is a pretty large group. Their primary outcome was the success of the SBT at, without having to re-intubate, within the 48 to 72-hour mark. You can see their secondary outcomes. Statistically, the only statistical difference was between the pressure support 30 minutes and the TPEs of 120. Cumulatively, I found this interesting, the rank. They were ranking them. So the rank was very interesting to me. The best was pressure support at 30 minutes, then 120 minutes, TPEs at 30, so TPEs at 120. So that supported my statement that I said a little bit ago, unless I'm going to put you on that for 120 minutes and see how you do, right? So basically, their basic conclusion was patients undergoing SBT using pressure support for 30 minutes are more likely to achieve both SBT and extubation success, especially if they're a simple wean. But they also looked at high risk in this. So undergoing prolonged wean or high risk of re-intubation, actually an SBT at 120 minutes with either PS or TPEs may aid in successful liberation. So I think it depends. If you're a simple wean, probably can get you off pretty quickly with that PSV of 30. But we all know we don't have simple weans only in our ICU. Wouldn't that be nice? RSBI. So raise of hands, how many people do RSBIs? Yeah, I think pretty much everybody, right? It's been out in the literature since 1991. Yang and Tobin really established this. It's a threshold of less than 105 breaths per liter per minute. It's kind of been an acceptable predictor of spontaneous breathing trials without any assistance. The only thing is I'm not sure people really read deep into this. The original study protocol actually disconnected patients from the vent and allowed them to breathe room air for this RSBI. How many of you disconnect your patient? I see no hands. I didn't either. So I'm not throwing stones here. Most use pressure support, PEEP, or CPAP. So some RCTs have shown that RSBI can prolong decisions to liberate. For example, this study that was actually also published in CHEST in 2022, where they conducted a systematic review and a meta-analysis. And they looked at 48 studies involving over 10,000 critically ill patients undergoing mechanical ventilation for 24 hours. And kind of looking at what happened with the RSBI. And what you look here is the sensitivity and specificity. I always jumble that up, sorry. You can see that the RSBI has moderate sensitivity and poor specificity, gosh, I'm sorry, for predicting success. Which is why I always said at our institution, please don't just rely on that RSBI. You have to take a look at the whole patient and see what's going on. You can't just think that an RSBI... And honestly, I've seen little old ladies, not anything against ladies, but little old ladies in their 80s, were never going to get an RSBI of less than 105. Sometimes you just got to pull the tube and pray, right? So there's things. Newer things that are out there. This is intriguing to me. I will be honest with you, at my practice, as I'm putting this together, I have never done long ultrasound as a way to determine a weaning tool. So I find this very interesting. I like ultrasound, but anyway. We all know that the diaphragm, we really need the diaphragm to function. It really is part of our tidal breathing. Ultrasound is a non-invasive way to measure the muscle thickness, the contractility, the muscle excursion at the bedside. We can see if that patient's diaphragm is even functioning the way we need it to before we extubate. So there's some studies, and I'm going to go through them. How do we compare our pressure time curves on the vent to what's happening in that long ultrasound to see whether that diaphragm's even functioning appropriately before you think about extubating your patient? So I'm going to talk through this one. This is Song et al. in 2022. It was a prospective observational study on patients who had been on the vent for more than 48 hours. They noted in their study that RSBI has some limitations, right? It's been the gold standard, but it's got limitations. What they did is, in that RSBI, you know where the tidal volume piece is. Instead of having tidal volume in their RSBI, they used diaphragmatic excursion and diaphragmatic thickening fraction is what they were assessing. And they put that into the formula of the RSBI. So what they wanted to figure out is if they used this information, could they predict better, like, chance of the patient not failing compared to traditional RSBI? And I know I'm going through these fast. You'll have access to these after the conference. So they did measurements in 130 subjects. They placed the subjects on a pressure support of eight without PEEP for a 30-minute SBT. At the end, they did their ultrasound, and they determined both the DE and the DTF. And then they also did an RSBI was measured with zero PEEP or zero pressure support, zero PEEP with flow triggered at two liters per minute and a bias flow of 10. This is really busy slides, so I'll do my best. But basically what they found was the best cutoff values for predicting failure was an RSBI of greater than 51.2 breaths per minute or breaths per minute per liter. The diaphragmatic excursion was less than 13.5 millimeters. The diaphragmatic thickening fraction was less than 30.9, and the DE to RSBI was greater than 1.38. And what you can see, I don't know if you can see my, yeah, I guess you can, sorry. What you can see over here is this black line is the RSBI. And you can see with the sensitivity and specificity that it's, this idea of lung ultrasound is actually better in predicting whether or not your patient is going to have failure. So their conclusions were the indices of the DE-RSBI and DTF-RSBI were reproducible values that were shown to predict weaning outcomes more accurately than RSBI used standalone. However, they do say this is their one study. We need more studies. So if any of you are out there interested in lung ultrasound, here you go. Here's an opportunity to do another study. The idea behind diaphragmatic electrical activity, bedside measurement, you know, we can look at EDI. We can look at EMG. So this is just another idea behind this. So there's a few studies of how to use this EADI or the EDI in liberation. So this is a study by Taylor and his group in 2022. They did a single center observational study. They only did 24 patients, but they compared EMG indices with diaphragmatic excursion. Again using, they used ultrasound to do this. Again another interesting idea. Their secondary outcomes were predictive measures. So again, if you can see the specificity, so the red line here is a, just RSBI by itself. The DE is the black line. I know it's really confusing. The blue line, which is really hard to see too, is the DTF and the NE. So basically they said DTF was superior, more accurate than DE in predicting extubation than other bedside measurements. So another idea of combining couple therapies or couple tools together to really predict whether or not this is going to work for them.

ventilator weaning

Spontaneous Breathing Trials

Rapid Shallow Breathing Index

diaphragmatic assessments

extubation outcomes