Hello Friends 👋
Join us in the third episode of our "Managing Respiratory Distress" series on The Incubator Podcast, featuring Dr. Lonnie Miner and Dr. Amy Miner. Our guests today unravel the intricacies of high-flow nasal cannula and CPAP in the treatment of respiratory distress syndrome (RDS) in neonates. Dr. Lonnie Miner, Assistant Professor in the Division of Neonatology at the University of Utah, School of Medicine, and Dr. Amy Miner, a Neonatology Fellow at Rutgers University, engage in a thorough discussion about the practical differences and physiological impacts of high-flow nasal cannula and CPAP. They emphasize the significance of understanding how much pressure is actually delivered to the neonates, exploring the challenges in measuring this accurately.
The conversation covers a range of topics, including the evolution of high-flow nasal cannula, its application in different clinical settings, and the importance of humidification in respiratory support. Our speakers also delve into the nuances of airway resistance and lung compliance, highlighting how these factors influence the effectiveness of respiratory support modalities.
Enjoy!
Our heartfelt thanks to Fisher & Paykel for sponsoring this series.
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Watch the video below to learn more about how interface design can affect your therapy outcomes, or for further insight into the evidence, download the NIV in NICU Clinical Evidence Summary Booklet.
Fisher & Paykel Healthcare offer a full neonatal care continuum which helps provide the best start possible to our precious babies worldwide.
To help demonstrate the importance of interface, Fisher & Paykel Healthcare have created a neonatal airway simulator (Baby LIV) which is based off a 28–30-week gestational age neonate. The simulator helps visualize pressure and flow therapies. For more information and to book an in-person demonstration, go to https://www.fphcare.com/us/hospital/infant-respiratory/cpap-interface-design/
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Short Bio: Lonnie Miner completed a degree in microbiology at Arizona State University followed by medical school at Saint Louis University School of Medicine. He completed residency training in pediatrics then a fellowship in neonatology at the University of Utah/Primary Children's Hospital and has worked with Intermountain Health since completing fellowship in 2004 (after spending 3 years working in urgent pediatric care with Intermountain as well). In addition, Lonnie was a full time faculty member with the University of Utah Division of Neonatology from 2015-2022 and continues to function as an adjunct assistant professor with rotations at Primary Children's Hosptial NICU on a regular basis. He has an interest in program development within neonatology and has been involved with development of neonatal programs within Intermountain Health since starting there. In addition, he has a focus on neonatal infections and is an active member of their Antimicrobial Stewardship Committee and has worked with the University of Utah/Primary Children's Congenital Cytomegalovirus Committee. As a practicing neonatologist, he naturally has an interest in respiratory management of all babies but has a developing interest in managing respiratory illness in the extremely low-birth weight baby as well as managing long-term chronic lung disease. Recent research has focused on non-invasive ventilation and different approaches to management. While there are many approaches to managing the respiratory status in the preterm infant, he is a firm believer in working toward more consistent approaches based on a solid understanding of neonatal physiology (with the understanding that it is changing at different gestational ages). Having been mentored by incredible teachers such as Dr. Don Null and Dr. Bradley Yoder, he strongly believes that the best approach is one that manages each infant based on the pathophysiology of their current disease state and it is vital we have a solid understanding of the devices we use to provide support and use them accordingly.
Short Bio: Dr. Amy Miner is a neonatal-perinatal fellow in the department of Neonatology at
Rutgers Robert Wood Johnson Medical School.
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The transcript for today's episode can be found below 👇:
Ben 00:00
Dr Lonnie Miner, Dr Amy Miner, thank you so much for making the time to be on with us today on the Incubator podcast. Thanks for having us. So we are continuing our series on the management of respiratory distress and neonates, talking about flow versus pressure, and I think that now today is the day that we will actually get into the nitty gritty of this discussion of flow versus pressure. I think that there's a lot of discussions about the use of high flow nasal cannula, especially in the context of RDS. Maybe as can one of you tell us a little bit, what is high flow nasal cannula and how is that different from CPAP?
Amy Miner 00:44
With CPAP we make a seal and we are delivering PEEP. With high flow nasal cannula, we are delivering a flow and then the kind of the unknown is how much pressure we're delivering, because as you deliver a flow, if the flow is high enough, then you're also going to deliver pressure Right, you'll still deliver distending pressure. So with high flow, part of the reason that it is theorized to work is that there is a washout and it overcomes the dead space. So that's, I think, one of the reasons that it works. But we also at times use it because it has that distending pressure, and I think that's one of the things that is important to understand is that we are giving some pressure. How much we're giving that still remains to be identified.
Lonnie Miner 01:45
And that's been part of the areas that we've done a little bit of research on using an artificial model. So one of the things we presented at PAS on a poster presentation that Amy did this last year, was comparing pressure and in that was at least measuring different flow rates with different high flow systems vapotherm, optiflow, junior, different ones that are that are available clinically and what we found is there's pretty much, if you're looking at, distending pressure when you're at your lower flows.
Again, the definition of high flow has varied over the years. When I actually first started practicing, around the time that high flow was becoming a thing, we actually used to make our own high flow devices by duct taping nasal cannula to a heater, because I was in St George at the time, where we're in the middle of a desert, it's super high, super it's not very humid. You know it's very dry there, sorry, and so we had a lot of babies with you know that we were trying to use higher flows that were having a lot of nasal nasal breakdown. So vapotherm they brought in their system over time and then we've had the Fisher-Paykel and other systems that have come in that provide heated, humidified high flow nasal cannula, and I think that's the thing to remember. It's not just high flow, it's an element of humidity and it's an element of heating and warming the gases that are transmitted to the baby.
Ben 03:19
I think this is. This is a critical point you're making. So if I turn on the flow and I put in on, I put the nasal cannula at a flow of five and I don't use any of the apparatus that you mentioned with humidifiers and stuff, what's the difference? What's the big deal? Why can I just crank up the flow and just slap on a cannula? What's the difference there?
Lonnie Miner 03:41
Like connecting it to the wall and just turning it up.
Ben 03:43
That's right.
Lonnie Miner 03:44
Yeah, which sometimes we see we'll have outside hospitals that are trying to get by until they get a transport team there and they'll do it. I think there's a number of issues that are there. Number one is when that's left in place over time, you're going to have a lot of dry out, you're going to have a lot of irritation to the nasal mucosa, you're going to have a lot of swelling. The other thing is is it's probably not as effective. The heating and the humidification allows for, I think, a better washout effect and you allow for better flow, better flow dynamics. That's kind of my personal take on it and that's what I've seen over the years as we've evolved in the use of the high flow cannula.
Ben 04:22
And I think this stems from from semantics, because I think it's funny when you, we say high flow and so we say, okay, so above a certain level, this is high flow, but actually when you read literature and you read papers, it is always written, as you mentioned it, lonnie, which is like humidified high flow, right, I mean, and that component of humidity is so important. I am wondering, amy, in your experience, what is considered high flow? At what point are we saying now, now you're on low flow, now you're on high flow. Is it one liter? Is it two liters? Like what? What have you? What is your? Your, your compartmentalization of the different modalities?
Amy Miner 05:02
There's not a really strict definition and so I've seen it different in different places, but typically I think of it anything over two liters, because at that point you you have to have, it has to be heated and humidified, but some sometimes it's more thought of three liters and above.
Lonnie Miner 05:24
So some of it's it's. It is a little bit of semantics, like Amy mentioned, and it's kind of a lesson in history. So when we were first developing high flow and when this was coming into being, we used to call it HHHFNC you know, the heated, humidified high flow nasal cannula. But we actually kind of arbitrarily had to pick a number that we would consider high flow. Part of it and this sounds silly it came from a billing issue when do you go from being intensive care to critical care, intensive care to critical?
Daphna 05:52
care that makes sense?
Lonnie Miner 05:55
Isn't so much of what we do driven by a billing issue and there was a fair amount of the respiratory literature that actually identified two liters as kind of a cutoff. There are some, some groups that actually, again coming from a semantics issue, will say two liters if you're less than 1500 grams, three liters if you're over, and then others, just to be consistent, will say two liters and above.
Daphna 06:19
So Thank you, I am. Before we get too far away from it. I want to go back and touch on something that you mentioned in some of the work that y'all have done at your institution. We have a lot of trainees who listen and I think sometimes it's a difficult concept for people coming into the field about we set a number right or we pick a number and the baby or the end alveoli don't always see that number. What is so complicated about measuring how much pressure or flow, in this case, we're able to give an infant?
Amy Miner 06:58
It depends so much on the resistance to flow, the lung compliance, and then you know how much pressure and flow you're still getting when you reach the distal alveoli. So you know we can say that we're giving a certain pressure. But usually that's measured right at the interface. I think there were a couple of studies initially that they were I think they were taking laryngeal measurements. But to actually measure the pressure that each alveoli is seeing, that's very difficult right.
Lonnie Miner 07:39
And I think that's one of the primary issues. That's the difference when we're talking about non-invasive versus invasive ventilation. With invasive ventilation I think we have some pretty good mechanical approaches to it, so to speak. I mean, depending on which ventilator you're using, you have an endotracheal tube in place. You hook a sensor up, either at the endotracheal tube or it's measured. You know behind the circuit and I think that's important to kind of know when you're doing that. But you know where your ventilator is measuring pressures. So that works very well with an inline endotracheal tube and you get a sense of what Excel tidal volumes are, what in-held tidal volumes are, those kind of things. There's really not a good model for looking at non-invasive measurements. So, like Amy mentioned, people have tried laryngeal measurements, they tried esophageal monometry and then artificial models. The biggest problem we've run into with artificial models is people will just kind of attach things to just a little device that measures pressure but it doesn't measure the airway resistance. So one of the biggest differences when you're talking about an endotracheal tube versus non-invasive is you're having to flow through all of the airway. You also have subglottic closure. That happens If you look at the rabbit model when you're doing different forms of non-invasive ventilation like nasal IMV. You know you'll have glottic closure with each breath if you're not careful. So you don't see that with your endotracheal tube measurements, so we don't really have a good way of measuring it exactly. Dr de Blassey has a pretty good in Seattle has an airway model that's hooked up toa fairly sophisticated system. We've been using one with the Fisher-Paykel folks that is a 3D CT scan of an artificial airway and it's not bad. It's a 750-gram baby that's taken from 3D CT modeling. It measures at the subglottis. The issue with that is we still don't have soft tissue. That's there.
Daphna 09:40
The floppiness factor.
Lonnie Miner 09:42
Floppiness, exactly. So we're measuring like a mouth open, mouth closed, it's probably somewhere in between. It's not exact, so it's a hard thing to measure. So I think a lot of it is. One of my original mentors was Don Null, if you guys are familiar with him, and his one of we still quote this around primary children's to this day and that is if all else fails, go look at your patient.
Daphna 10:10
Love that.
Lonnie Miner 10:11
Love that. So you always have to remember that probably what you're seeing on your settings whether it's bubble cpap, whether it's the ventilator and that is affected by your nasal interface is probably never truly what you're seeing delivered to the baby itself.
Daphna 10:31
I appreciate that and we've talked a lot about resistance and interfaces, and so our sense in the community is that most people start babies on CPAP and use high flow as like a weaning modality. But why not start high flow as like a primary intention?
Amy Miner 10:47
There was a study now I can't remember when it was done, but they looked at non-inferiority between CPAP and high flow as post-extubation in infants. I believe it was 28 to 32 weeks. I could be wrong on the gestation, but it was a post-extubation first intention and there was no difference, no long-term difference. So it certainly could be right and it comes down a lot to the comfort of the providers, of the nurses who are applying it, that it's something that everybody is familiar with and comfortable and knows how to use right.
Lonnie Miner 11:32
And some of it. Just so you know, there are some places that do, and even within our. So one of the biggest issues within I work primarily for Intermountain Healthcare in conjunction with the University of Utah. We have multiple centers and we find that there's a lot of variability between centers. So at one center that I've worked at for years and years, we actually would start babies on a high flow of eight and that was kind of a, and we actually had very good outcomes for quite a long time with that, whereas another center is very aggressive with CPAP and will you CPAP up to eight to 10 in their starting areas. And then we have other places that are in the middle and it's CPAP of six to eight. So one of the things we've been trying to do over time is develop a little bit more of a consistent approach, but you certainly do need to think how to put it. I think it's really important that as a group, you're consistent with what you do, that you understand the nuances of each system that you're using and what its capabilities are, and try to pick and choose which patients are the appropriate patients for that interface. It's like you need to do that with applying noninvasive ventilation. There are some babies that do, in my mind, probably need to be intubated sooner than later, especially if they failed an initial trial. I think all babies deserve a little bit of an initial trial during resuscitation, right. But if you've got a baby, whether they're term and they're super sick with a pneumonia or a meconium aspiration or an extremely low birth weight of 24 to 26 weeks, which we're still trying to figure out how to manage those babies best if they're not flying and they're not improving, then you need to move more quickly to innovation. The things that we found with high flow that are interesting is that there's kind of an exponential curve. So when you go from two liters to three liters to four liters, there's not a lot of peep that's delivered, but you do get a CO2 washout and in fact, some of those lower flows may be better for achieving a CO2 washout in a patient who's, because you get more turbulence and you get more. You may have more of an improvement from that standpoint. If you've got a baby that's needing recruitment and is having issues with oxygenation, then you need something that's going to apply some kind of distending pressure. Amy and I are work there and she can comment on this. More is once we reduce the pressure and reached a flow of about six, we found that we would start on this artificial model. Sorry, I should have described that and I apologize.
Ben 14:14
No worries.
Lonnie Miner 14:15
This is on that artificial model that we were using and these were presented at PAS, so they're available to look at and we're in the process of writing the papers for publication. We did find that you start to see a peep of about three and then there was a little bit of almost of an exponential curve, that by the time you get to a high flow of eight you have a peep of about five, and then we actually tested it all the way up to 15, which most of us probably wouldn't do in a low birth weight baby.
Ben 14:44
No, I can speak for many of us on this one.
Lonnie Miner 14:48
I've got a six kilo kid that I'm doing 12 liters on. But that's kind of a little sketchy but the baby's got a lot of. He's a very complicated chronic lung disease kid. But once you reach about eight you've got that all the way up to 15, I think we got up to we kind of plateau and you end up with a peep somewhere between six to eight when you get up to flows of that high.
Ben 15:13
So the heuristic of saying that maybe a peep of five is equivalent to a high flow of five liters, which I'm going to raise my hand and say that as a first and second year fellow I use that then eventually you learn what you guys just mentioned. It's really not something that can be used in the NICU. It's not a good rule. It's not a good rule to follow right, correct. And so I think you mentioned something, lonnie, that's interesting, which is that you said it's important to differentiate whether you want to treat maybe hypoxemia versus ventilatory failure, and I think that's something that many people sometimes compound, can confuse, and we're not really good sometimes at teasing these two apart. But can you, can maybe, amy, or you, lonnie, go into a little bit what is the difference between hypoxemia and ventilatory failure and what kind of differences are there when it comes to the needs of the patient regarding management?
Amy Miner 16:16
So you know, with hypoxemia, you're looking at your, your FiO2 delivery and and your oxygenation, and that's we typically think of peep. So in that sense, that's where you would be more concerned about making sure that you have that. You are, you have some pressure delivery right, but the thing that that is unique, I think, about high flow that Lonnie mentioned, is that there is pretty significant CO2 washout, so that even at the lower flows then then you're going to affect your CO2, which would be your, your, your ventilation right. So that I mean, I think I think that's something that maybe we don't really think about differentiating that that you can take that into consideration, depending on on clinically what. What is the concerns with the, with the baby?
Lonnie Miner 17:14
And I think what you're trying to make sure that you're doing is is is sometimes these two things overlap. So, like you know, when, when folks use the oscillator and I know that's, you know that's not the topic of our conversation here, necessarily, but everybody talks about mean airway pressures, oxygenation, amplitude, is, you know, ventilation. What I found, though, is if you don't get a baby's lungs open and you don't achieve an optimal lung volume so I always think in terms of an optimal lung volume strategy. So, no matter what I'm trying to do, I need to achieve recruitment, right, that's the very first thing Then you can't ventilate the baby very well. In your in your ventilatory efforts Don't work if you don't have the lung recruited. Then, as you recruit the lung, you both improve your oxygenation and your ventilation. Now, if you've got a well, a well recruited lung, then the issue might be or the baby's able to maintain that recruitment on their own. Then, again, it might be that they need you know something, you know thinking more of a, more of a high flow, something that helps ease the baby's work of breathing, helps them to maintain recruitment, which high flow can do. So I'm still a huge proponent of starting the CPAP, using that to achieve good recruitment, making sure you establish an early FRC in a baby, a functional residual capacity, and then from there seeing what the baby needs. If the baby's able to do that on their own, however, then you know you don't necessarily want to apply a system to them that may actually complicate things. You know people always talk about pneumothoracies. I actually worry a little bit more about just getting this baby over distended and then having this baby trying to breathe against things with this big barrel test. Does that make sense? It does. One of the things I try to when I work with the residents and fellows. I actually have a number of articles I like them to read, and one of the things I like them to think about is there's actually a good article that I think it was Alan Job and Reese Clark and Brad Yoder and Dale Gerstman wrote. Like it was so long ago that when I asked Brad about it he forgot he had written it. He's like oh, did I write that?
Ben 19:22
But that could be because he also publishes a lot.
Lonnie Miner 19:26
Yes, that's it, you know, but it's a very nice review article where basically they go through where does lung injury come from? So when I start a conversation on different modalities of ventilation or what I'm teaching residents and fellows about the different nuances of the conventional versus high frequency ventilation, I always start with where does lung injury come from? Because you first need to understand your pathophysiology and then you apply your ventilatory or your respiratory support based on the pathophysiology of your baby, and that's something that Don Noel taught us very on when I was a fellow, and Brad Yoder has continued that teaching and training is my mentor to this day. So I worry about atelectasis and sheer trauma, I worry about volume trauma. I worry about hypoxia, you know, and hyperoxia and you know free radical formation, and I worry about inflammation down the road, you know. Lower on the list is barrow trauma. Everybody is like barrow trauma. When I ask the residents where does lung injury come from? Well, let's talk about that. So I think your first thing is you've got to whatever you need to do. You establish a good FRC. A lot of times that takes a CPAP device that's delivering a true amount of peep and that can be, depending on what your institution is used to, as long as it's working, you know, five to six versus six to eight, depending on your different places. But the main thing is is look at your patient, see what their oxygen needs are. If, as you establish an FRC, those oxygen needs should be improving, their work of breathing should be improving and then you move forward from there. The other article I always like the residents and fellows to read is the AAP guideline on noninvasive ventilation and the premature infant, and basically it's start with noninvasive ventilation, try to optimize that as best as you can and then move towards some form of surfactant delivery into base. You know we've got all that's all over the place these days. Right, that's a whole other podcast. But anyways, move towards some other form of more invasive ventilation if you need to. But don't let the baby linger, but give them an opportunity to recruit. But then don't let them sit there for a prolonged period of time having ongoing atelectatic lung damage.
Ben 21:52
It does make sense, and I think what I think is a great jumping point for us is the fact that I'm going to bring this up in the form of a sort of a myth, or again one of these heuristics where there's some people who often say well, if you're delivering CPAP we've mentioned how giving support via nasal cannula at certain flows can deliver some form of positive and expiratory pressure. But there's there's an argument to be made that once we are picking certain interfaces for the delivery of CPAP ones that introduce leakage right, ones that are not completely including the nears, and so on and so forth Some people are saying then, well, you may think you're selling CPAP, but you're kind of on high flow nasal cannula, and so I am wondering if you guys can talk a little bit about your experience with that specifically, and whether you do believe that it is the case that if you are on a CPAP plus five with a form of nasal cannula that has a lot of leak around the nears, then yeah, effectively you are not delivering the PP of set and you're on on a quote unquote fake high flow nasal cannula. Or if we have to be more moderated when we address that issue.
Amy Miner 23:13
Unfortunately, I think the lines are very blurred right between CPAP and high flow that you can have, have your interface and having your head that I'm on high flow, for example, or I'm on CPAP but are you really delivering what you think you're delivering so with? With the study that we did, we showed that with high flow you can deliver the, the positive index, the Tory pressure, right. You've got your distending pressure and so you can have. You can be on high flow but still be delivering a peep, as you would with CPAP. So I think it's really just looking at what are your goals of therapy and and where is your infant at this point in in in the growth and development. For example, if you're on CPAP but you're baby is, you know 38 weeks and you still haven't been able to introduce feeding and and you know some of these developmental goals, then you can put the baby on high flow, still get some of that pressure that you need, but then it would free the baby up to be able to to do other things right and including bonding with parents like there are. There are a lot of advantages of being on high flow as long as you're able to deliver enough peep, knowing that certainly you're not going to deliver as much as you would on CPAP.
Lonnie Miner 24:53
So, and Ben, to go back to your question a little bit too, as far as different, it sounds to me like kind of different interfaces. So I think one of the things that people want to do is they just figure well, if I just stick something on a CPAP device, that it's just fine and I don't have issues with it. In that I one of the reasons that we started looking at things with this artificial model that we did is because I was bugged by lots of opinions but very little information, and I'm kind of one of those that's like, okay, let's do stuff, but let's make sure we know what we're doing right, so, so, so we've got that. So, amy, amy specific focus was looking at the high flow area and kind of, what are we doing with high flow nasal cannula? And then my part of our project was looking at more of a more of the nasal interfaces with CPAP. And those were and I think the important thing there is this I don't necessarily advocate one over the other. You know I try to be very careful and I walked into this with the idea of being that I actually kind of expected them to be equivalent. And specifically we're talking OptiFlow Junior being hooked up to nasal IMV, the RAMCAM being used for CPAP and nasal IMV, and then we use the one of the FlexiTrunk devices. But there's also I haven't looked at Hudson prongs, but you know there's a lot of that's what I used back in the day was the Hudson prongs and I think that's what they're still using at Columbia, if I'm correct, and I think Oregon. So what we found with doing that is not all devices are equal for delivering PEEP and back pressure. However, there's different, as Amy mentioned, and I think it's a very important point. There are developmental implications to these different devices that you're using. So if you need to recruit along, you want to make sure that you're using as close to your set PEEP and having that as close to your delivered PEEP as possible. And in the things that we looked at, we found that you need a true, in a sense, standard or, trying to get the right word not old fashioned but traditional, traditional, thanks to more of a traditional CPAP device. So something that has an inspiratory limb, has an expiratory limb. And then you mentioned you know that they're not inclusive probably even more importantly that are probably as important as that is the resistance in the circuit for what you're, the flow that you're trying to deliver. That helps deliver the PEEP. So we found that pretty much a traditional CPAP system would give you pretty that delivered, you know, through the nares on this artificial model to a subglottic area would give you pretty close to your set set. Peep was within, you know, it was probably like one less. There was a little bit of a drop off. And we found that same thing when we did it with the nasal IMV system Although we can talk later. Not all nasal IMV settings are equivalent as far as how the pressure to the RAM can, non-inclusive, delivered a significantly less amount of PEEP. It would give us at most about three and a half centimeters of water. Now that's with a small baby system, not with more of the pediatric ones that are that are bigger, bore, with less resistance, and that's something I haven't looked at and probably would like to see with models of bigger babies in the future, especially trying to manage chronic lung babies that just can't keep anything on their face. I find that that system can sometimes be helpful. And then I found that the Optiflow junior system just should not be hooked up to a CPAP system. It's there for high flow but it only could deliver at max about one and a half centimeters of water PEEP, no matter how high you ran your. We ran up to a total of 15 liters of flow and 10 centimeters of water PEEP, both with bubble CPAP systems and with ventilator systems, and really found that the and then even on nasal IMV settings up to like a PEEP of 30 and a PEEP of 12, the optiflow junior could only deliver a couple centimeters of water PEEP at best. So so just knowing that I think is important, because if you're in the early phases you need to recruit right. You're going to want to have a more exact PEEP, you're going to want to try and open those lungs. Then you have a baby. That maybe isn't a more chronic phase and maybe it's OK to have three and a half centimeters of water PEEP and have a baby that is more comfortable with the, you know with with the nasal interface, so that he can be held, he can have playtime, he can do things like that. So either high flow cannula at a higher level or a RAM can in one of these systems. Maybe the better, the better approach.
Ben 29:34
I think it's such an interesting transition because, as neonatologist and as providers, we tend to do a very rough association of like. This thing does this job right, so it's like the cooling blanket that just cools the baby. When I have a patient with HIE, the incubator provides warmth and humidity and the ventilator provides the respiratory support that I want. But what I'm learning from, from you both and throughout the series, is that there's really a responsibility of the clinicians to really familiarize yourself with what is available within your unit, to understand how you are achieving the goals you set for yourself and the patient, and that's something that is probably the product of modern neonatology and something that more providers should be aware of, and I think that's very interesting.
Lonnie Miner 30:22
Well, I found it was. It was a funny, it was just a just kind of a commentary on that. When I presented some of this data at WSPR I mentioned, you know, one of the questions was was well, you're doing? You know, amy had presented the high flow data and then I presented our CPAP and a lot of folks were kind of aghast it oh my gosh, you're using eight liters of flow. And I asked him he says well, how much flow do you use on your CPAP? And it's interesting. I had a I had a large number of neonatologists turn and look to look at each other, experienced old dogs like me that were like um, what do we set our flows at? You know? And actually that flow on your, especially on bubble CPAP, is really critical for achieving you know, your, your recruitment and making sure your bubbler is working like it should you know so, and it can range anywhere from eight to 10 to 12. Usually that's kind of the range that I'm seeing. What's interesting is when you read studies on comparing things. Those things aren't often put into the studies and I'm always find that interesting when I'm trying to figure out why is this showing a better outcome than this? Sometimes I think it's missing components of what people are doing clinically at the bedside and they may not quite know. So that's a good comment, ben, I appreciate that.
Daphna 31:41
We've talked a lot about the upper limits of high flow and kind of our starting perimeters. But I have a question on the other end of the spectrum. So you know we've got these babies who have been on high flow for weeks and weeks and weeks. Every time we try to take them off they don't do well, kind of what are your clinical perimeters? How do you decide? Do I keep weaning the high flow? Do I just transition this kid to nasal cannula? How do you know how much nasal cannula to make at that transition time?
Lonnie Miner 32:14
This is a really interesting question because, depending on where you're at, we're incredibly inconsistent.
Daphna 32:21
I think even even within the same unit, we're probably.
Lonnie Miner 32:25
Oh yeah, like I'm in attending to attending.
Daphna 32:26
That's right yeah absolutely so.
Lonnie Miner 32:28
That's why this comes up, because I'll come on service after you know I'll come on for one of my partners who will have a baby on a certain level of flow thinking you know. Again, that isn't consistent with the information that Amy and I have looked at. You know, Amy's study showed very clearly that you need to be on at least a flow of about you know, at least five, going on six, before you start to see any Pete. But I'll have individuals leaving babies on a flow of two, thinking that while we're providing some back pressure to kind of do things and you're not, but you may be helping ease the work of breathing, you may be helping the baby breathe a little easier. So that is an awesome question. Part of it, I think, it depends on your baby. Are we treating a premature baby with RDS? Are we treating a term baby with pneumonia? And I think that's a different. Each one has a different, a different approach. One of the ways that we're and I think if you were to ask Dr Pollan, who was previously on here, you know I think there's some thoughts on how long we should leave babies on peep. So within the Intermountain System, we're just now rolling out a new BPD kind of protocol and doing it as a QI project. And this has been a large group, that group effort with medical directors and respiratory therapy directors and everybody from across our system. What we're moving towards is early traditional CPAP, with you know, here it's a flexi trunk, but whether it's Hudson-Pronx flexi I don't think that necessarily matters, but more of an early traditional CPAP inspiratory limb, expiratory limb, occlusive CPAP recruit and then, once the baby is weaned gradually to about five centimeters of water, then transitioning over to maybe a more developmentally appropriate system. And we actually have left some leeway for those who really feel that the RAM can is more appropriate versus high flow. So we kind of have two options High flow of six versus a RAM can with a peep that we think would give about three centimeters of water and then at least leaving them on a certain amount of peep until they're about 32 weeks gestation and then from there we're going to see how it goes because it's probably going to get all inconsistent again. But the idea is we're trying to create some consistency, follow our outcome, see if we improve our chronic lung disease rates, maybe improve our bedside caregivers satisfaction with us as medical providers not changing things on a regular basis every day, which I think is a huge issue, and then see if there's some thought that maybe leaving babies on a level of peep that might mimic the intra-amniotic fluid pressure until they're a little older may help with pulmonary development.
Ben 35:15
Yeah, we've started doing that too, okay. So we started doing that too, especially in babies at high risk of BPD, to try to leave them on on a bit of positive end-expiratory pressure to promote long growth, and that's something that I'm seeing more and more as well. How's that going for you guys? Very well, very well. We find that the process of winning these babies is much more rapid around the 32 week mark rather than, as Daphna was mentioning. We all remember these babies that they were sort of do you're like, oh, but they've been doing relatively okay for this long and you just can't get them off that little bit of either peep or flow, and I think that has to do with the fact that you recruited a few of your line that are working pretty well and you're, and the rest are just shriveled away.
Lonnie Miner 36:02
I think one of the issues that we have with this, though, is we'll have a kid parked on six leaders, and I've had a few babies I've trialed, and I kind of like to hear more about your guys's outcomes and take this back to our group. But you know, I've left them on six leaders until 32 weeks, and then, like you said, ben, what I see is they they sit on six leaders 21% for like the last week, and then they just, and then you just wean rapidly and they do great. I think the biggest problem we have is a little bit of a paradigm shift that it is okay to sit on six leaders 21%, that even though the baby's saturations are 98 to 100, you're not on oxygen. We have this, this innate reflex of like but, but I got to wean.
Ben 36:44
I mean, I have to lower something.
Daphna 36:49
I'll tell you, in our unit I'm a, I'm a conservative, I wean slowly and Ben will come on and the parents love it when Ben comes off because he's been watching the baby From afar and he's decided the baby's ready so they'll go from. You know the, you know four liters of high flow, high flow, six liters of high flow just to to off, and he's the. He's always the hero in the unit.
Lonnie Miner 37:15
So I have that same issue with Brad Yoder. He'll come on on call and he watches all these babies from afar and I'll come in the next morning and he knows we and I he and I have worked together for I mean, I completely trust Brad and you know, come on and he's like, oh, I'm going to be on the phone, I'll part blotch whatever he feels is appropriate. So I'll come in the next morning and half my babies will be extubated.
Daphna 37:34
Yeah, exactly Right, okay, and they do great, and they do great. It's infuriating.
Lonnie Miner 37:43
Amy, did you have any other comments or?
Amy Miner 37:47
There's a couple. There were a couple of studies, there was a Cochrane review and there was a made analysis recently that looked at this very thing. They were looking at what is the best way to win your non-invasive support and they looked at the CPAP like taking breaks off of CPAP or just weaning the peep, and then when to come off of peep, when to go on to high flow if that's what you're going to do when to go to nasal cannula and they looked at a whole lot of studies and the end result was that it's certainly weaning slowly versus just stopping abruptly, which we could have predicted results in less time on CPAP overall and less time requiring oxygen. But overall there wasn't a really huge consensus on what is the best way to step down. So I think it really is a lot of watching your baby and seeing how you can do. And then the big question remains. That, I think, is a really interesting one. There was just a study I think it was a LAM at all just did a study and Dr Polin has done these studies before through Columbia where they're looking at the effect of CPAP or any distending pressure on the development of the alveoli and that idea that if we leave them on with some distending pressure for a longer amount of time, are we improving the growth of the alveoli and then, long term, improving their long term pulmonary outcomes?
Ben 39:35
As we're getting close to the end of the conversation, I wanted to ask a question because when I was a resident, I have to admit we still used oxyhoods. What happened to oxyhoods?
Lonnie Miner 39:46
You know we find an occasional. I may have to answer this because I don't know that Amy's ever seen an oxyhood.
Amy Miner 39:52
I guess we do use them at one of our hospitals. Okay, there you go.
Lonnie Miner 39:57
We find them locked, we find them in storage closets every once in a while and the RT will walk out and go. What is this? And you know, we actually in the inner mountain system, oh boy, probably almost 15 to 20 years ago, we went to a whole early lung recruitment kind of strategy where, when babies are transitioning, we actually will place them on some form of positive pressure to help them transition. And it's interesting because, if you know, lucky Jane did a lot of work back in the day where he looked at, you know, sodium chloride and sodium potassium chloride transporters and found that different babies have different speeds at which they'll, you know, clear the lung fluid. So we found that by doing a little bit of positive pressure, we actually have dropped significantly our newborn ICU admission rates as well as our rates from level one and level two units that needed transport. So we've actually, you know, killed our bottom line, so to speak, while keeping babies closer to parents by helping them transition better. I would say that the worst pneumothoracies I've ever seen were babies that set on head boxes for a long time at outside hospitals awaiting transport, because, again, they never established an FRC, they basically just had this thing over giving them oxygen, all the hypoxia and all the stuff you're bleeding in and they would just have ongoing shear trauma to the lungs, over and over and over every time they breathe and they would come in and they had really difficult clinical courses. Since we've gone to the early lung recruitment kind of thought process, establishing an early functional residual capacity, I see far less babies coming in with that kind of really ugly, you know, recurrent pneumothoracies, really really hammered lungs from coming from outside places.
Amy Miner 41:54
It's interesting. Just a couple of times at one of our outside hospitals overnight they've pulled this out of wherever it's stored and then it's quickly. You know we quickly transitioned the baby off. I think it's interesting that there's evidence to show that it is going to increase your risk of pneumothoracies. But I'm just, I guess I was surprised that I did see it a couple of times, but certainly I would not personally recommend it.
Lonnie Miner 42:29
I think everybody has a different approach and I think that's the important thing, and my biggest thing is is always remember, is, you know, just really try to practice from the standpoint of thinking about what is the physiology of your baby, you know, based on gestational age, based on their clinical condition, based on the reason they're born and what's going on around the time of birth, and always think about the pathophysiology of lung disease and what you're trying to accomplish with whatever you're doing.
Ben 42:56
And you know what I think it is is that number one access to evidence based practices is difficult. So if you don't speak English, if you don't have institutional access to get to read those papers, that's number one. Getting that's what we're trying to do with the podcast as well. Getting the experience of other people, what other people have been able to do and what have their experiences been like, is something that is not easily accessible and I think that, as a clinician, if you're used to doing something, there's momentum for these practices and the ability to change those practices is very difficult. And so I think, for everybody also listening to us around the globe because the audience of the incubator really is, it does not just contain in the US I think it's very important to know that you can manage your babies very appropriately with a bubble CPAP which, when you're thinking in terms of resources, is also very low tech, as we've said many times, and you're probably going to get better outcomes. I think that's critical for people to hear, because I haven't seen a bubble. I haven't seen an oxyhood since fellowship, basically, but I have seen oxyhoods. If I'm giving a talk somewhere outside the US and visiting NICUs, I see oxyhoods and you wonder if I don't think people are married to the oxyhood, but they just maybe need this reassurance like, hey, we've tried the transition and we're doing fine, and that could be very helpful.
Lonnie Miner 44:19
And sometimes it's all you have, so the other part is as well. Okay, let's take the pieces of the oxyhood and maybe turn it into a bubble CPAP device. That's right, yeah.
Daphna 44:28
I mean, it's because of people's ingenuity and willingness to try new things that I mean neonatology even exists, right, like we took machines that were not intended to be used on tiny, immature humans and we made them work not me, but you guys. People made it work, and so I'm grateful for all those people who took the ingenuity to make the field what it is today.
Lonnie Miner 45:01
Same. I've had the privilege of working with a lot of those individuals, you know, having practiced for the last 20 plus years and, you know, and spending my residency in fellowship, being able to hear them talk about, oh yeah, remember when that oscillator popped its top and it hit the top of the thing, things that we would never do in a million years, but that's all they had. You know, the developers were factored, all of those things. So, yeah, no, it's incredible. I think the other thing, too, is change is hard. When I was first training the Columbia, a lot of the Columbia discussion was happening and all of the things they were doing with bubble CPAP.
Ben 45:38
Dr Polin called it a religion, by the way, just so you know.
Lonnie Miner 45:41
You know what it needs to be a religion to make it work, and the reason they have such good outcomes is because they believe in it. Their staff has buy-in. So, yeah, I like that. We actually thought they were nuts. We started we were like what? And they no, and you have to, you know, and you got to, you know. And then Morley came out with the coin trial and all these. And then, as Columbia's experience came out, and we realized no, they really these. They're not making this up, this is real. And then we started doing it ourselves. But again, we had to, we had to get converted and we had to buy into it. And then we had to convert our bedside caregivers, because that's where it happens If you're going to make non-invasive ventilation happen, it's our bedside caregivers that really make that happen. I can write orders all day long, but once they have a buy into it, I've I've had, you know, I've had nurses come up to me and RT's no, this is what we're going to do and this is the best way, and I'm like yeah, yeah, yeah, I think that's.
Ben 46:43
That's another great point that buy-in is probably sometimes supersedes evidence-based practices. You better, you're better off with consistent buy-in than with with inconsistent evidence-based practices, unfortunately. Dr Lonnie Miner, dr Amy Miner, thank you so much for making the time to be with us today. We have one more episode coming up in this discussion. Actually, we have two more episodes coming up in this discussion and we're looking forward to chatting with you more, but thank you again for making the time to be with us today. Definitely, thank you, as usual.
Amy Miner 47:12
Hi everybody, thank you, it was a pleasure.
Lonnie Miner 47:15
Thank you for having us.