Latest / CRITKNOW / Beyond the Data: SOHO
Transcript
- Ramesh Venkataraman: Hi everyone, ⁓ Ramesh here along with Bharat and for the first time here in Krittanoh we have our first ⁓ expert guest Dr. Ram Rajagopalan. It's a pleasure and honor to have you Ram with us all the more because ⁓ he's my first teacher in critical care medicine who inspired me to get into critical care medicine. So now I'm very happy that ⁓ he's our first expert guest. He's one of the pioneers of critical care medicine in India, ex-president of the Indian Society of Critical Care Medicine. Ram Rajagopalan: All Ramesh Venkataraman: extremely knowledgeable original thinker in the field of critical care medicine who has actually influenced practice and the careers of so many people is currently the head and the professor of critical care medicine at Ramchandra Medical College and University. So Ram, it's a pleasure and honor to have you in our podcast as a guest and looking forward to your deep insights as always. Over to you. Ram Rajagopalan: . Thank you. Thank you. I'm very flattered to be the first ⁓ invitee on your podcast. I've been watching the ⁓ previous viral sessions and they've been brilliant. I hope I can contribute something. Bharath Kumar T V: Thank you so much Dr. Ram and welcome to CRITNO. It's an absolute pleasure to have you and thanks for all of your support and encouragement so far. ⁓ So this is actually a follow up to the SOHO trial review that Ramesh and I recorded. So maybe we'll start, I wanna ask you ⁓ before we get into the trial itself. ⁓ So HFNC has sort of dominated respiratory support, I would say in the last 10 to 15 years, perhaps. ⁓ And of course, the pandemic gave a sort of a huge boost to HFNC usage. Maybe you can briefly talk us through how you have seen the device evolve ⁓ in your own ⁓ in your experience, both from evidence, also from a clinical standpoint. Maybe we can start there. Ram Rajagopalan: Okay, yeah, I've seen it from the time when it was used dominantly in neonates, when it was used like a substitute for the CPAP device that they were using in those situation. And we didn't think much of it for adult use. Probably the first time we started thinking about it is probably in the late 2000s, early 2000s, 2010s or so, when the initial stages studies started coming out and some of them were just. ⁓ not randomized trials, but about that same time I had the opportunity of having what is called the Monal ventilator the T75 which had an option of providing high flow at the same time and we sort of experimented. really without knowing whether it will be beneficial. In situations where there were elderly people, people who didn't want to go on a ventilator, we were trying to see if we can guide them through the hypoxic respiratory failure. And anecdotally it sounded great. I mean, it worked very well in some of those patients. But I suppose the boost that we got to the use of HFNO dominantly was from the Florali trial, which paradoxically is also the Areva group. that was responsible for that study. And I think we need to be a little careful. We were very optimistic about that trial, which was actually not powered to detect a difference in mortality. But when it showed us a difference in mortality, we all jumped on it and said, ⁓ it's going to be perfectly fine for the management of hypoxic respiratory failure. I think till I saw this SOHO trial, I didn't actually look at it carefully enough. the benefit that it showed retrospectively, they said, OK, maybe because the re-intubation in patients with severe hypoxia was what was seen. At the same time, maybe a year or two later, its use in post extubation failure or prevention of post extubation failure became extremely prominent. The first trials were actually ⁓ in patients with very low risk of extubation failure and then subsequently ⁓ when it was a non inferiority trial compared to NIV ⁓ in high risk failure and we seem to be again. ⁓ very enamored by the fact that it's an easy device to use. ⁓ Most recently after that, I think the COVID epidemic clearly reinforced our use, not only because of I think we lacked enough ventilators and we were a little frustrated about the management of hypoxia in these patients that we are using it, especially when combined with, ⁓ know, spontaneous broning of these patients. Again, anecdotally, it seemed lovely in terms of its effect. When you go back and look at the genuine outcomes with COVID, there's been a lot of variability. But I still remember, my memory was there was a Colombian trial that initially came out, a randomized trial, which showed a strong benefit. I decided to ignore all other information that came. There's a lot of heterogeneity in the outcomes. But we decided that it's going to be very effective. Again most recently I suppose last year the renovate comparisons of patients with quite a variety of hypoxic respiratory failure seem to imply that it was certainly non inferior to NIV, but we know for a fact that NIV is not a great tool for hypoxic respiratory failure by itself. So, at least we needed to be, I mean we had some kind of a feeling that it is even though would be a good option to be used under these circumstances. Bharath Kumar T V: Yeah, no, that's those are all great points. Thank you. Ramesh Venkataraman: I think you have summed it up. context of the SOHO trial so beautifully Ram. My question to you is as a clinician where do you see the role of when you mentioned non-invasive ventilation not being a great tool for acute hypoxic respiratory failure to be precise. As a clinician where do you see NIVs use versus HFNC use in your ICU along with the cost implications associated with it and the outcomes that you would specifically look for in your patients. Ram Rajagopalan: When we talk about the utility and the outcome, it is clearly going to be dependent on the indication that you are going to be using it for very clearly in hypoxic respiratory failure with the very clear exception of acute cardiogenic pulmonary edema and probably you know patients with acute exacerbation of COPD. I do know whether they would not be strongly ⁓ hypoxic respiratory failure. Under both of those conditions there was a certain amount of doubt about the efficacy of high flow nasal canola, but in virtually every other situation there was seeming you know at least non inferiority for the high flow nasal canola. to the point where we would use it for the initial management of the patients, ok. And again when you look at a lot of the recommendations the ARDS and the prevention of ventilatory when VAP for instance, both of them strongly recommend the use of some kind of a non-invasive process before you intubate the patient. So, for that reason alone we were using HFNC dominantly for hypoxic respiratory failure other than acute pulmonary edema and we were using NIV in the other circumstances. Again, from the extubation point of view, we decided that we could use either one of these devices for the patients with a relatively low risk for extubation, not necessarily with too many ⁓ negative parameters. But if the patient has a phenomenally high risk, there was at least one trial that showed that NIV was significantly better. So, our tendency to use ⁓ in high risk patients, the NIV is more than it would be of a high So, when you come back and talk about the renovate, it said everybody including acute pulmonary edema and COPD, but they were a little cautious about the fact that they did not want extrapolate in those two groups because the numbers were relatively on the small side. ⁓ So, in general our approach is exactly that. We do give a trial for most of these patients before they get incubated. ⁓ Cost wise it is very comparative I suppose whether you buy a mask for the NIV or whether you going to have a the specialized canola for the high flow nasal canola. I do know whether the cost is very significantly different between the two. So, we generally use one or the other on a very routine basis. Bharath Kumar T V: Yeah, no. I guess, you know, on your point about using it for, you know, using HFNC specifically for acute hypoxic respiratory failure, right? One of the... concerns that we've discussed, it's been discussed in the literature, but also discussed clinically every day is, is there a possibility that there's a delay in intubation, right? Now in the SOHO trial, that didn't seem to bear out, but clinically at the bedside, if you are using HFNC, how do you sort of monitor these patients and what is your trigger for escalating to the next level of support? So a couple of questions there. Do you try NIV in those cases before you intubate or do you proceed to intubating directly? And how do you sort of keep track of progress and how do you decide, no, no, this is the time to intubate? Ram Rajagopalan: Definitely one of the ⁓ important aspects of the use of high flow nasal canola is you have to do it in a unit that has the capable capability of monitoring these patients closely and considering intubation early when we have to absolutely. ⁓ As far as the high flow nasal canola is concerned. We've been very strong about using something like the ROX index, which looks at your spO2 and fIo2 ratio against the respiratory rate. And it's rather intuitive if your requirement for oxygen is going to remain very high. And for me, anybody who remains on more than 60 % fIo2 with the highest flow for about a couple of hours and who continues to have a respiratory rate that is in the 40s will always meet the ROX criteria. I don't want to use a specific cutoff. can quote the numbers and say 2.5. Bharath Kumar T V: Mm. Ram Rajagopalan: 4.88 and 2.85, but I do think most of us understand that, but very broadly if the oxygenation remains poor and if the respiratory rate does not seem to settle within a couple of hours, we definitely would reconsider the advancing to the next step. The choice of whether you are going to use NIV as a stop gap between intubating the patient is I am getting less and less you know optimistic about it, it doesn't necessarily work. I think again there will be an added delay that you will be introducing at that point in time that if you see somebody who not responding to a high flow considering intubating the patient would be reasonably logical. So that is probably the way I would go and I would be very emphatic that this can only be done in a unit where there is 24 hour coverage by competent individuals who can intubate the patient at the same Otherwise the excess risk that you're going to have in terms of mortality is not acceptable. Ramesh Venkataraman: It is just for the audience just quickly take home points from what you have said so far is no do not delay intubation on HFNC. You feel that NIV as an interim to intubation is probably going to only delay the intubation. So, if somebody fails HFNC you should think of early intubation monitor them closely. For lack of better criteria, think 65 % FIO2 with whatever high flows with the respiratory rate still high, more than 30, 35, consistently with no response in the first two hours. I think we should all think about going for intubation. think those are wise words from lot of years of experience. I think those take home messages would be very useful for our audience. So now quickly going through the SOHO ⁓ benefit. Ram Rajagopalan: ⁓ Ramesh Venkataraman: but then there seems to be a benefit in terms of preventing intubations. What are your thoughts, about the trial and has your views on the use of HFNC changed after the trial has been published? Ram Rajagopalan: As far as the SOHO trial ⁓ and the fact it didn't show a benefit. is not unexpected primarily because the SOHO trial was probably constructed with an intent of demonstrating what they saw was a hypothesis generated in the earlier REBA trial. So, on that basis the fluoride trial that they had. So, the fact that they didn't show a difference in survival is not something that is bothering me, but the fact that they didn't show a major reduction in your rate of intubation was something that bothers me. As you pointed out. the number needed to treat of about 17 seems a little too small. So, I want it to be a genuine effect. And as I was arguing that maybe if you look at the confidence interval, you can even say it is closer to 10 to 12. But still for every patient that is tried on a high flow nasal cannula, the benefit that you're going to see is going to be quite modest. So in that sense, it does affect the way in which I approach this. But at the same time, I continue to do it? I still think considering the risks that we have with ventilator associated pneumonia, and particularly the nature of the organisms that is present in our country, an attempt at avoiding intubation, even if it's 1 in 10 or maybe even 1 in 15. I think it is worthwhile as a process as long as we monitor it closely. Bharath Kumar T V: Yeah, I was actually going to sort of ⁓ come to that point, you know, because, yes, it's a 6 % reduction, maybe not as impressive as we want. ⁓ But, you know, like you said, in our context with the kind of infections that we see, right, it maybe it makes sense to still try HFNC because if you're able to avoid those intubations, right, many of the downstream complications are perhaps less likely to occur, right? So I was going to ask if that you shared that feeling or thought, right? Yeah. And it does appear that you do, Ram Rajagopalan: absolutely. Yeah, I completely feel strongly about it. fact, I'm not going to abandon my HFNC use, but I'm definitely going to be worried about the fact that it's not going to be the panacea that we were hoping. Bharath Kumar T V: Yeah. Ramesh Venkataraman: think the SOHO trial tells us not to avoid HFNC but maybe narrow the scope that we could ⁓ out of HFNC in terms of what and when we would use and how long. I think that probably is important. I think it was great picking your brain on these important thoughts Ram and we're very happy. ⁓ you just summarize ⁓ key take home messages for our audience so that ⁓ all this ⁓ that you would probably give them few points of... ⁓ Ram Rajagopalan: Absolutely. Absolutely. Yeah. Ramesh Venkataraman: clinical relevance practice. Ram Rajagopalan: It is very tempting to believe that the HFNC is going to be the solution to avoiding intubation of these patients. It is not going to. The two specific areas where I find that a NIV can still be a considerable benefit is in patients with acute cardiogenic palmedema and in patients who have ⁓ COPD and in both of those situations I think the benefit is very clearly for the NIV. In the rest of it, hypoxic respiratory failure. If you are going to use HFNC, we do recognize that we are not going to change mortality very significantly, but we are going to probably reduce the intubation to a modest extent, it not really a dramatic. And I would suggest that if you are going to consider it for this kind of a modest benefit that you should do it with the greatest amount of monitoring and with the intent of intubating the patient early when you see a decompensation. It's not a solution. It's not like you're to put the HFNC and walk away. Bharath Kumar T V: Yeah, yeah, I think that's a very important point. And on those words of wisdom, I think it's a good place to stop. ⁓ Thank so much, Dr. Ram, for joining us. We are looking forward to having you on many more of these sessions. ⁓ think we, ⁓ Ramesh and I, but also obviously all our listeners are going to benefit ⁓ from all of your input and all of your comments and thoughts. So thank you so much. It's been a great pleasure. Ram Rajagopalan: Thank you. ⁓ I am thrilled by being the first one on this podcast, which I, after seeing a of them, I've become a major admirer. No questions about it. Thank you. Ramesh Venkataraman: Thanks, sir. Thank you. Bharath Kumar T V: Thank you. Ramesh Venkataraman: Thank you. Bharath Kumar T V: Thank you so much.