SCCMPod-559 PCCM: Optimizing Time to Extubation in the PICU

Dr. Mack: Hello, and welcome to the Society of Critical Care Medicine podcast. I'm your host, Dr. Elizabeth Mack, and today I'm speaking with Dr. Rebecca Mitting, MD, MRC, PCH, about the article, Sedation and Ventilator Weaning Bundle and Time to Extubation in Infants with Bronchiolitis, Secondary Analysis of the Sedation and Weaning in Children or Sandwich Trial, published in April 2025 issue of Pediatric Critical Care Medicine. To access the full article, visit pccmjournal.org.

Dr. Mitting is a consultant pediatric intensivist and clinical lead for the PICU at Imperial College Healthcare NHS Trust in London, United Kingdom. Dr. Mitting is also an honorary senior clinical lecturer at Imperial College London. Welcome, Dr. Mitting. Hi, thank you very much for inviting me to talk about this on your podcast. Awesome. Before we get started, do you have any disclosures to report?

Dr. Mitting: No, I don't have any disclosures. 

Dr. Mack: Wonderful. Well, thank you for this contribution to the literature.

We'd love to get started by just asking, how did you get the idea for this trial? Were you already connected with the other sites or what was the connection there?

Dr. Mitting: So this was a post hoc subgroup secondary analysis of the sandwich trial data set. It's a real interest of mine that I feel really strongly that when families have given us permission to collect data about their children during their admission to the PICU, we should really maximize all of the opportunities that we have to use that data to learn and to study the populations that we're interested in as researchers. So the sandwich trial was a really large trial conducted in UK PICUs.

And as such, there's a data set containing information about over 10,000 PICU admissions available for secondary analysis. And so we conducted this post hoc analysis to try to learn a little bit more about the subgroup of patients with bronchiolitis included within that trial.

Dr. Mack: Wonderful. Thank you so much. We'd love to hear a little bit about that previously published sandwich trial, including specifically the intervention focused on sedation and vent weaning.

What was that bundle? What was the trial design? We'd love to hear a little bit more.

Dr. Mitting: Yeah. So the sandwich trial was an extremely large clinical trial and we were unable to do that because of the step wedge cluster randomization design of the trial. And the sandwich intervention was a combined intervention looking at sedation adequacy scoring using the comfort B sedation score with nurse-led weaning of sedation titrating to a kind of sedation goal set on daily ward rounds.

And that was combined with a protocolized extubation readiness testing intervention. So at set times of the day for the centers that were participating in the intervention, children would undergo protocolized nurse-led extubation readiness testing. And the trial was conducted at 17 PICUs in the United Kingdom.

What I mean by the cluster implementation methodology is that each of those PICUs kind of crossed over to being in the intervention at one point during another trial. So every month that the trial was running, one PICU crossed over to being in the intervention. So all of the staff were trained, everybody was kind of aware of the intervention, and then all patients in that implementation peer were exposed to the intervention.

The results of the trial was that the trial did have a statistically significant impact on the primary outcome. So the primary outcome was time to successful extubation. And there was a statistically significant difference in outcomes, but it was a very small difference, around one hour difference.

And I guess the question is, is that maybe that's not clinically significant to the people who are taking the paper, the idea that you might reduce the average duration of mechanical ventilation by one hour. And so what we wanted to do in this study is to take, because the original study looked at a very heterogeneous population, it included every single child in the PICU. So obviously there's going to be children within that cohort who were never going to be extubated on that day because they've had airway surgery or they've got cardiac surgery.

There's many other reasons not extubating them on that day. So we thought, what about if we consider a more homogeneous subgroup of patients? So we chose, because it's probably the largest group, we chose bronchiolitis patients who are aged under one year at the time of their PICU admission to see if the effect size of the intervention was larger in this more homogeneous subgroup who were also admitted with a respiratory failure.

So, you know, didn't have potentially other reasons not to be extubated on that day.

Dr. Mack: Wonderful. And what did you find when you looked at that more homogeneous subgroup?

Dr. Mitting: Yeah. So when we looked at this, so there were 784 babies who had a diagnosis of bronchiolitis and were less than 12 months old on admission within this trial dataset. And we did find that there was a much larger difference in time to successful extubation when you just consider this subgroup.

So infants who were exposed to the intervention, the median time to successful extubation was 69.6 hours and it was 86.4 in the non-exposed infants. And I think that that kind of 16, 17 hour difference in time to successful extubation is likely to be much more significant to clinicians thinking about whether to implement the intervention. And I think the other thing that's important to consider, I suppose, and this is potentially another explanation for our findings as well, is that in PICU, bronchiolitis causes lots of our seasonal beds pressures.

So it's responsible for lots of our ICU strain. A lot of our workload, so 25% of our workload comes in a very short period of time during the RSV and other respiratory winter virus season. And so the ICU system at that time is under a lot of pressure.

So that's important for a couple of reasons. One, it should be very appealing to clinicians that you might be able to get people extubated a bit quicker if you did use the intervention because we're all under pressure to maintain patient flow and get patients through the PICU. But also it may, I suppose, be an explanation for the finding that we do know that protocolised care works very well when we're under strain.

You know, that the idea that we can be a bit more uniform and utilise protocolised care probably helps us when we're extremely busy and we maybe don't have time for the kind of individualised care you might have during the summer months. So maybe that goes some way to explain where the benefit lies in this winter pressure.

Dr. Mack: Absolutely. I think that's significant for not only our care teams, but also the patients and the families. So thank you for sharing that.

Can you share a bit about your definitions of unplanned extubation and emergency re-intubation for those that failed extubation, just so we can understand a bit more about the outcomes you were looking at?

Dr. Mitting: Yeah, so we record unplanned extubation in the UK as a patient safety metric. It's recorded as one of our outcomes on the PICONET database. And it's defined in their data manual as a dislodgement of the endotracheal tube when the intention wasn't to extubate that patient immediately and the airway team or a team of airway competent staff are not in the bed space.

That's kind of important as a UK safety metric and a metric of, I suppose, staffing adequacy and other things. And there was an increased incidence of unplanned extubation in children exposed to the intervention in the Sandwich trial. And so that's probably of important focus to clinicians because it's generally regarded as something that you would like to avoid.

Extubation failure, on the other hand, is defined as the requirement for re-intubation in the PICU following an attempt to extubation. For the purposes of this analysis, we didn't exclude unplanned extubation from that definition. So some of the children with a failed extubation, it will have been an unplanned extubation that required intubation, though we know that around a third to a half of children who experienced an unplanned extubation don't require re-intubation after that.

Dr. Mack: Awesome. I think all of us as intensivists grapple with these trade-offs every day and would just love to hear a little bit more about your thoughts on those sorts of trade-offs. So duration on the ventilator weighed with potential increase for unplanned extubation.

Obviously, there are lots of complications that can come with ventilator days.

Dr. Mitting: So we'd love to hear your thoughts on that. Yeah, I think this is a really important trade-off. And this is a kind of a decision we make every day when we do ward rounds on the PICU, isn't it?

That we know that having extubation failure or experiencing extubation failure is extremely bad for individual patients. In most cohort studies, it's associated with mortality. And in all cohort studies, it's associated with a long increase in duration of mechanical ventilation.

So for the individual patient who experiences extubation failure, it's definitely bad and we want to try to avoid it. However, obviously, if we take an extremely risk-averse attitude to our patients and we delay extubating everybody because we're really desperate to try to avoid extubation failure, we may expose patients to longer periods of invasive mechanical ventilation. And that, of course, also relates to longer periods of sedation exposure and the side effects and adverse effects associated with that.

And I think that's really important to pediatric patients, especially because of all of the worries about the neurodevelopmental after effects of prolonged PICU stays with exposure to sedation. So as part of the secondary analysis, we had a look at the relationship between frequency of re-intubation requirement at trial sites and the average time to a successful extubation at trial site. And we did confirm that there was a statistically significant negative correlation between frequency of failed extubation and overall duration of mechanical ventilation.

And I suppose that just highlights that for the population, it may not be beneficial to be risk-averse and to delay extubation attempts to avoid failure. But obviously, for the individual, avoidance of extubation failure is really important. I suppose when you think about what this might mean for the future, then we need to be better at predicting extubation failure.

We need to be better at knowing who might require dexamethasone for prevention of airway obstruction and targeting use of non-invasive ventilation and hyponasal cannula to the patients who definitely need it. And our assessment of risk using personalized medicine and other predictive models to try to see if we can be better at getting this right so that we reduce extubation failure without increasing the population exposure to mechanical ventilation. And of course, sedation is a byproduct of that.

Dr. Mack: Thank you. We'd love to hear a little bit about, other than a pandemic, what's been going on in your world related to this work since the trial ended. Have you all been approaching care differently?

What's next in the queue? We'd love to hear a little bit more.

Dr. Mitting: So I think that's a really interesting question. And this trial was conducted in 2018 and 2019. So that's a really important kind of period in the history of PICU now, isn't it?

Although we didn't know it at the time. All of the trial units, all of these 17 PICUs, which is the majority of UK PICUs, we're quite a small country, were trained and implemented fully this bundle. And then we had the pandemic, COVID hit.

And almost all of the UK PICUs were then transitioned into adult intensive care units, completely repurposed. All of our protocols went out the window. There was a lot of staff turnover and a lot of change for everybody working in the PICUs.

This paper was then published in 2021. And that was really right in the middle of the COVID pandemic for us. So our restrictions on socialisation didn't end until July 2021.

So within this kind of social and political context, as well as the trial being published with a quite a small effect size, I think really have impacted the long term implementation to the bundle within the UK. And so actually, when I surveyed UK PICUs after this trial was published, the implementation of this has not been widespread. I don't think there are many UK PICUs who are using the intervention in its wholeness in every part of it.

So you know, the sedation scoring, the goal setting, the protocolised extubation readiness, I don't think that's been implemented on a very wide scale. So I think partly, I'd like to think that demonstrating that actually the effect size in certain very important subgroups is it may actually be larger and more clinically significant than in the overall heterogeneous population may help to persuade clinicians to implement protocolised weaning, especially during the winter months when we're experiencing high levels of ICU strain. But I think it's a really important place of work, a really important thing that we need to study within the UK that we're now producing quite regularly, large scale, high quality interventional randomised control trials in PICU populations.

But little really is known about whether the findings are implemented on the ground, whether actually trials like OxyPICU and soon to be finished pressure and gastric are going to change actual, you know, bedside nurse clinical practice on the ground in future in the PICU. And I think implementation science and studying implementation is a really important and interesting kind of future area that we need to be looking at when we think about all of the money and not only money, all of the kind of generosity of parents and patients who've allowed us to study them and to collect their data and whether that is actually translating into change in practice, which is what we all hope for.

Dr. Mack: If I may, I'd love to hear what's been the impact on your personal practice or your PICU where you work. Did this stick or has there been so much change? There's been incredible turnover and that kind of thing.

Dr. Mitting: Yeah, so we do look at this regularly on our PICU. I think we have definitely implemented comfort B scoring and sedation adequacy scoring as a whole, as well as titrating to sedation goals. And I think that's stuck.

We've all just been to the Paediatric Critical Care Society conference in Belfast and some of our nurses presented an audit of extubation readiness. So it was called spontaneous breeding to SBTs within the sandwich trial. And they audited our practice and actually probably around half of the children who were extubated hadn't had the kind of sandwich protocolized extubation readiness testing.

I think one of the really interesting things that we found was that 100% of children who had an extubation readiness test in the audit that the nurses did went on to be extubated that day. And what that says to me is that what we're doing is we're only doing it in the children we know we're going to extubate anyway. We're not doing it in the protocolized nurse-led fashion that kind of I think was meant for the trial that we do it in everybody, irrespective of what the doctors think, to try to improve our unit awareness of which children are ready to extubate.

And I think that's an area of work that we're looking at in our PICU now is that can we go back to doing this on a more protocolized nurse-led widespread fashion so that we kind of stick to the intervention as it was meant in the original trial work. So I think yeah, there's work to be done in our PICU. And I'm sure that resonates with lots of other UK clinicians that this hasn't been implemented religiously and wide scale yet.

Dr. Mack: I think the impact of change that we all experienced resonates widely in so many things needing a reset. So thank you for that. And there's probably some benefit to even a standardized approach among those who we expect to extubate.

But I hear you that we're sometimes surprised and really a more universal approach is helpful. Anything else that you would like to share that we haven't discussed?

Dr. Mitting: Only really that I would like to thank Sam Ray, who's my colleague at Great Ormond Street, who worked with me on this analysis. And also to thank Brona and Cleona for being so generous with sharing of the trial data and supportive of the use of this rich resource in the trial dataset from the sandwich trial.

Dr. Mack: And thank you and your teams and the 17 units that conducted this work and all of the patients and families who contributed such an important contribution. Thank you so much for inviting me and giving me the opportunity to talk about this work. This concludes another episode of the Society of Critical Care Medicine podcast.

If you're listening on your favorite podcast app and you like what you heard, consider rating and leaving a review. For the Society of Critical Care Medicine, I'm Dr. Elizabeth Mack.

Announcer: Elizabeth H. Mack, MD, MS, FCCM, is a professor of pediatrics and chief of pediatric critical care at Medical University of South Carolina Children's Health in Charleston, South Carolina. Join or renew your membership with SCCM, the only multiprofessional society dedicated exclusively to the advancement of critical care.

Contact a customer service representative at 847-827-6888 or visit sccm.org/membership for more information. The SCCM podcast is the copyrighted material of the Society of Critical Care Medicine, and all rights are reserved. Find more episodes at sccm.org/podcast. This podcast is for educational purposes only. The material presented is intended to represent an approach, view, statement, or opinion of the presenter that may be helpful to others. The views and opinions expressed herein are those of the presenters and do not necessarily reflect the opinions or views of SCCM.

SCCM does not recommend or endorse any specific test, physician, product, procedure, opinion, or other information that may be mentioned.