Thank you, Todd, and thank you for putting us in this enormous room. All the important people are here, though, so that's good. All right. So best practice for spontaneous breathing trials. These are my disclosures, none of which are relevant to today's topic. When we talk about liberating patients from mechanical ventilation, you have to balance outcomes. What we're trying to balance here is if you maintain patients on invasive ventilation for too long, bad things start to happen, including adverse effects and higher costs. If you try to push patients too fast off mechanical ventilation, you end up with an acceptably high extubation failure rate, which have been associated with adverse patient trajectories, higher costs, and possibly even mortality. To try to get an idea of what the world landscape was for ventilation liberation, Jeremy Lohberger and Sommer recently published this international survey just trying to get a temperature for what people were doing. And when faced with a clinical case that is clearly ready to move towards extubation, about 44% of people thought that they will do a spontaneous breathing trial, but do so out of protocol. They don't have an organized way of proceeding, whereas about 40% have a well-organized protocol, and for about 13% of people, they just have a gut feeling that you are moving in the direction of extubation. When you ask how you do this, most people use some pressure support augmentation, but this is really not a monolith. Hidden in there are people who would use five pressure support, eight pressure support, 10 pressure support, so kind of a free-for-all as well. And don't even get me started on how long the trial should last, because about a third in each category will do it for 30 minutes, 30 to 60 minutes, or greater than an hour. So these guidelines that just were published a few months ago, led by Sommer and Robby Kamani, involved a number of international experts, 26 diverse panels, and tried to address 11 PICO questions. The methodology, it was somewhat complex, but if there was great agreement within the experts, we would move towards a guideline-type recommendation. If there was no consensus agreement, there was a systematic review that was conducted on a particular topic, and then experts came up with guidelines using great methodology. The 11 PICO questions are shown here. I'm not going to spend time on all of them, but I will encourage you to read the actual guidelines. I think it's quite well-referenced and explanatory. I'm going to focus on these three questions that pertain to spontaneous breathing trials. Spontaneous breathing trials, question number one is, should we do them? And if so, how? And for how long? So I'm going to try to tease this out a little bit more. The question number one is, should every acutely hospitalized child on conventional ventilation for more than 24 hours be subjected to a spontaneous breathing trial as part of the extubation readiness? There are a few clinical studies that were used to base this guideline. This recommendation, I'm going to quote or highlight this one by colleagues and friends from Sao Paulo, Brazil, who randomized about just over 250 patients to a standard care-type liberation versus daily extubation readiness trials with spontaneous breathing trials. And what they showed was that by having a well-organized protocol with a daily SBT, that you shorten mechanical ventilation time. This is emblematic of what most studies have shown. We identified three randomized trials, three QI studies, and two observational studies. The summary here is that SBTs were associated with a lower extubation failure rate in most studies, or there was no difference. But no study showed a higher extubation failure rate with the performance of an SBT. The diagnostic accuracy showed a 90% or greater positive predictive value for successful extubation. SBT performance was associated with a shorter duration of mechanical ventilation, or no difference. And no studies have shown a longer duration of mechanical ventilation. So I think these are all compelling reasons to do an SBT. So the recommendation by consensus of this core statement was that we suggest that an SBT be part of an ERT bundle so you can independently assess the patient's likelihood of having a successful extubation. So now that we established that we should do this, how should we do it? Should we use pressure support augmentation, or just place patients on CPAP or PEEP or TPs? And of course, when we think of pressure support augmentation, we think of all the reasons why we've been lied to, that we need pressure support augmentation, such as you have a small tube and you're breathing through a straw. Well, that is a good application of the Poiseuille's Law. If I were to breathe through a 7-0 tube, I would be breathing much more easily than if I were breathing through a 3-0 tube. And yes, I would be breathing through a straw. But as Robby Kamani and the CHLA group very elegantly demonstrated, a size-appropriate endotracheal tube provides irrelevant resistance to a size-appropriate patient with a size-appropriate flow. Meaning, if one large patient were to breathe through a 6-0 tube, there is less resistance than breathing through a 3-0 tube. But a 3-0 tube belongs with patients that are breathing in this area over here, the neonates. And so regardless of what tube we're going to use, the resistance of the airway with a breathing tube that is appropriately sized is going to be lower than that of the native airway. So you don't need pressure support augmentation based on ET tube size. To further illustrate this point, they looked at the pressure rate product, which is how fast and how hard you're breathing. And notice that the lower is better. When you pressure support augment at spontaneous breathing trial, your pressure rate product is very low. If you just use CPAP, it approximates the pressure rate product that that patient will encounter after extubation. So CPAP alone is a much better approximator of what kind of effort this patient is going to sustain after extubation. So if you use pressure support, the concern would be that perhaps you're putting lipstick on patients who are going to fail a spontaneous breathing trial, but wouldn't otherwise if you use pressure support. Turns out this study from Farias from 2001 show that the likelihood of successful extubation in this cohort, which is a cohort of general ICU intubated patients, was the same whether you use pressure support augmentation or TPs. Their intubation rates were the same. And most importantly, the trial failure was the same. So in this general sample, whether you use pressure support or not, it didn't make a difference. And also the patient trajectory markers were very equivalent. Another study looking at just under 250 intubated patients assigned to receive pressure support augmentation or just CPAP also showed that it didn't really make a difference. You were not making patients who were not going to pass the SBT trial pass, and then they go on to fail. So how to do this? The recommendation is a bit hedging. We recommend that you can use pressure support augmentation or not use pressure support augmentation for patients that have standard risk. However, if you have a high-risk patient, doing spontaneous breathing trial without pressure support will more likely help you delineate which patients are not ready to separate. But who are those high-risk patients? Well, this table will show you that. I'm not going to read all those. They are the usual suspects of myocardial dysfunction, neuromuscular disorders, chronic illness. But most importantly, also patients who fail the previous extubation, and also patients that are borderline passing the spontaneous breathing trial. So now that we talked about whether we should do it and how we should do it, how long should we do it for? And again, this is a place where there has been a knowledge gap. A few recent studies have come along to inform the field. This is also a study from CHLA looking at the timing of SBT failure and showing that if you run a spontaneous breathing trial for 120 minutes, there is a significant number of patients that will fail a spontaneous breathing trial after passing at the 30-minute mark. So that's a group of interest because if you just do short SBTs, you are not going to capture those failures. So how far are those failures really translating into failure to extubate, which is the million dollar question. So out of the 305 SBTs in this cohort, 43% were successful, 33% were early failures, 25% were late failures. Of the patients, the 88% who passed their ERT or their SBT on the day of extubation, there was a 9% extubation rate. To me, the interesting question is, there were patients that failed their SBT on extubation date and went on to be extubated, and their extubation failure rate was also quite low. So to me, this is quite interesting because you are now, you could say that the longer you keep on SBT, the more failure you're going to identify. But is that fair failure? Is that the failure you're trying to identify to inform your decision to extubate or not? What these data tell me is that some patients who fail their longer SBT can still be extubated and will still do okay. So the recommendation here was, we suggest that the SBT should be conducted for either 30 minutes, which is sufficient for most patients, or 60 to 120 minutes for those at higher risk of extubation. If you have a higher risk of extubation failure, as we determined from that table, perhaps a 60 to 100 minute extubation trial or spontaneous breathing trial is for you. So I'm going to stop here, and we'll come back with questions later. But thank you very much. Thank you.

spontaneous breathing trials

mechanical ventilation weaning

extubation readiness

CPAP pressure support

patient risk assessment