Showing posts with label high-flow. Show all posts
Showing posts with label high-flow. Show all posts

Thursday, September 26, 2019

High Flow Nasal Cannula: Does it Ventilate COPD Patients?

I've reviewed numerous mechanisms of action and functions of High Flow Nasal Cannula but I haven't touch on whether or not it works to help ventilate patients. I have discussed in the mechanisms of action that it does wash out the CO2 from the dead space in the nasopharynx, oropharynx, etc, but does that show a numerical decrease in the PCO2? The studies I had reviewed prior to this one weren't promising. 

One of the indirect ways that HFNC can bring down CO2 is by bringing down the patients respiratory rate. There's plenty of data to support the decrease in the respiratory rate. Since the person isn't breathing as hard nor as fast, less CO2 is produced. Less CO2 is produced means the patients needs to be ventilated less. Things get better. Prior to this study, though, the data just wasn't there to show that this actually happened in a statistically significant way. I've said this before and I'll say this again, I will not recommend HFNC to a patient with a COPD patient sucking wind in the ED with an exacerbation that has a gas that looks like 7.06/96/66. That patient either needs some non-invasive ventilation with a very close eye or the endotracheal tube.

In this study they placed COPD patients, not in exacerbation, on HFNC and measured a number of parameters but you and I are here for the CO2. Patients had their PCO2 measured at baseline, on 20L HFNC, and at 30L HFNC. At 20L the PCO2 was at approximately 91 (plus or minus 6.7)% of their baseline and at 30L their PCO2 was at approximately 87.4 (plus or minus 6.2) % of their baseline. That data was statistically significant.

This may be completely out of bounds but if we can (although I probably shouldn't) extrapolate that to a patient with a PCO2 of 60, 20L should bring them down to approximately 54.6 and 30L down to 52.4. Something is better than nothing and if you can hold the patient over while they get their steroids and nebulizations, it may be worth a try in the real world.

- EJ



Bräunlich J, Köhler M, Wirtz H. Nasal highflow improves ventilation in patients with COPD. International Journal of Chronic Obstructive Pulmonary Disease. 2016;1077-1085.

Link to Abstract

Link to Full Free Article

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

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Tuesday, September 24, 2019

High Flow Nasal Cannula in Acute Decompensated Heart Failure data leaves much to be desired.

Fortunately in the critical ill population, we do not necessarily have to abide by the saying that "if all you have is a hammer, everything looks like a nail". What I'm referring to is regarding utilizing high-flow nasal cannula in acute heart failure exacerbations. I already dissected how HFNC generated a "PEEP" equivalent airway pressure and the data behind that statement. The amount of PEEP varies and it drops by a statistically significant difference if the patient has their mouth open. If a patient presents to the emergency department, or someone gets overzealous with maintenance fluids, with an acute heart failure exacerbation, there is data that I will be reviewing here where HFNC is an option. But let's be honest with ourselves, though, non-invasive ventilation (colloquially known as BiPAP, although CPAP has data for working as well) is the better option because it provides positive airway pressure more reliably that HFNC. Sometimes these patients just need the ventilator as well. All three studies are FREE that I am going to be reviewing here and I recommend you read them for yourself rather than trusting my takedown of them. That's your disclaimer.

The first study published in 2011 out of Spain was a look at just 5 patients. I know, don't fall off of your seat. I can't criticize because I don't do any research outside of read other peoples research. One needs to remember that in 2011 the HFNC systems were not readily available for historical context. These 5 patients were treated in the emergency department with NIV and then I guess they were diuresed aggressively there. Why do I guess? Well the study does not report the BNP nor the achieved diuresis in these 5 patients. Big weakness in the study. They looked at a multitude of parameters that would be standard for a study of this nature, i.e. to see if HFNC is better than the other oxygen devices, but there are big problems. You see, the authors looked at the parameters before HFNC and then 24 hours AFTER HFNC. What they don't say is how much the patients were diuresed in the interim. Of course the PaO2 is going to improve. Of course the dyspnea is going to improve. Of course the respiratory rate is going to improve! Anyway, this is a study worth sticking in our back pockets to know it happened and move forward.

The second study by Roca also out of Spain in 2013 wanted to assess if HFNC helped with the hemodynamic parameters. They hypothesized that HFNC in patients with heart failure could be associated with a decrease in preload without changing the cardiac output. To look at this, patients got sequential echo's to assess cardiac function. Pretty good setup if you ask me. The 10 patients enrolled in this study were all stable. Therefore the data needs to be extrapolated to the sick patients. They did a baseline TTE on these patients, then hooked them up to the HFNC system at 20L, checked an echo, then at 40L of flow, and checked an echo. They did all sort of echocardiographic wizardry to obtain their results. They found that HFNC may be associated with a decrease in preload justified by the lack of IVC collapse on inspiration without any changes to cardiac function. IVC measurements are their own can of worms when used for resuscitation but this is very standardized and methodical. The most interesting finding that I enjoyed was the decrease in respiratory rate noted by these patients. At baseline, their RR was 23 breaths per minute. At 20L this fell to 17 bpm. At 40L this fell to 13 bpm. Cool stuff! Note that the patients were receiving just flow in this study as the FiO2 was set to 21% (room air). The authors chose to not use patients in acute decompensated heart failure for this study as there would have been too much variability in the subjects themselves along with their responses to the treatments interfering with to the measures. Obviously if they dump out a liter due to furosemide their hemodynamic parameters are going to change and it'll mask out the effect of the HFNC or provide confounders.

The third and last study I'm going to share with you all today comes from our colleagues in South Korea who performed a retrospective cohort analysis where patients were divided into a HFNC group or an intubation group after oxygenation with a facemask at a flow rate of 10L/min or more. These authors jumped on the opportunity to look at this data as they hadn't seen any published data about using HFNC in patients with acute heart failure exacerbations. They looked at approximately 5 years of data to place 73 patients in the intubation group and 76 patients in the HFNC group. Since this was a retrospective study, the decision as to what arm the patients fell in was at the discretion of the physician at bedside. The authors are just looking back in time at why they decided to do it and how the patients did. It seems as if they ignored the NIV data. I could be wrong. The baseline characteristics of the two arms were similar with nothing too eye catching. These patients were looked at for 6 hours. There were no statistically significant changes in the physiologic responses between the two groups. There was also no difference in the clinical outcomes between the two groups. This oddly, in my opinion, includes vasopressor/ionotrope use. I mention this because patients who are intubated typically have sedation. Also, the medications utilized for intubation could have an effect on hemodynamic parameters that are not noted here. It's just something that, from a personal experience standpoint, has me a bit curious. The p-value for that is 0.051. If the sample size would've been larger, I'm sure that would've been a notable difference. The authors noted all these limitations to their study and agree that what we really need is a prospective, multicentered, randomized, controlled trial. I agree

To conclude, I think the best we have right now in the absence of concrete data is clinical judgment, my favorite. One could try to place the patient on HFNC to either keep them away from the ventilator or even keep them from being annoyed by the CPAP/BiPAP mask which is typically uncomfortable, limits the ability to eat, speak, and other fun activities. If it fails, it fails. Your RT may be a little annoyed at you and may say "I told you so", but ultimately we have to do what's best for the patient. Thoughts? Please read these articles for yourself. A hat tip to all the authors. 

- EJ





Link to Abstract

Link to Full FREE PDF



Link to Abstract

Link to not free PDF




Link to Abstract

Link to Full FREE PDF
Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

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Sunday, September 22, 2019

High-flow Nasal Cannula: What is it?

High-flow nasal cannula oxygen therapy in adults

Some of you have asked what I mean every time I post something regarding high flow nasal cannula. Let's start by defining the flow in the different oxygen devices. Regular nasal cannula provides between 1-6 liters of flow. A simple face mask can get you flows between 6-10L/min. Venti masks, aka Venturi masks can get you flow rates between 4-8L/min. The best you can potentially do with a non-high flow device is the non-rebreather which can generate a flow rate of 10-15L/min. Just so we are all clear, every time I see a patient on a non-rebreather my senses step up to the next level. To me, that thing strapped on a patients face means that a decision needs to be made stat as the person who placed it on their face needs a second opinion. It's time to either place the patient on HFNC, BiPAP, intubate, or my favorite, they just panicked and didn't know what to do. It happens.

I like the image in particular because it is not signaling any machine in particular. There are a number of different companies who make these devices and I do not know the nitty gritty as to what differentiates them. I just know I love the technology. Would you all like for me to make a YouTube video where I break down the mechanisms of action of the device?

This article is a good review for the time, published in 2015, with the data that existed at the moment. The author reviews the physiologic effects, discusses the dead space washout, the PEEP effect, the benefits of heat and humidification. In addition, they discuss clinical uses such as both hypoxemic and hypercapnic respiratory failure, pre-intubation, post-extubation, sleep apnea, heart failure, and others.

It's definitely worth a quick read.

-EJ








Nishimura, M. (2015). High-flow nasal cannula oxygen therapy in adults. Journal of Intensive Care, 3(1).

Link to Abstract

Link to full FREE PDF

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

My Amazon Store

Monday, September 16, 2019

High Flow Nasal Cannula: A beautiful image of the mechanisms of action

Not Just Oxygen? Mechanisms of Benefit from High-Flow Nasal Cannula in Hypoxemic Respiratory Failure.




Link to Abstract

Link to Image

Goligher, E. C., Slutsky, A. S. (2017). Not Just Oxygen? Mechanisms of Benefit from High-Flow Nasal Cannula in Hypoxemic Respiratory Failure. American Journal of Respiratory and Critical Care Medicine, 195(9), 1128–1131.

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

My Amazon Store

Sunday, September 15, 2019

High Flow Nasal Cannula in the Emergency Department: Can it avoid intubations?

Randomized Controlled Trial of Humidified High-Flow Nasal Oxygen for Acute Respiratory Distress in the Emergency Department: The HOT-ER Study

This study was the first randomized control trial looking at whether high-flow nasal cannula decreases the need for mechanical ventilation in the emergency department. In addition they looked at emergency department and hospital lengths of stays, 90 day mortality, adverse effects in the hospital, and patient experience. I sympathize for the authors of this study because their abstract shows results that my not in fact be true. I state this because, although the study took over two years to complete, they did not collect sufficient patients to demonstrate an effect on their primary outcome which was a need for mechanical ventilation. Unfortunately, they needed 900 based on post-hoc analysis and obtained 322 patients. It would have taken them approximately 6 years to get this trial done. Sigh. The other caveat to this trial is that the sickest patients were plucked out by the physicians after recruitment because they wanted to proceed with NIV/BiPAP before even trying HFNC. I can't say I blame them. I treat patients and trials be damned if my clinical judgement is telling me to do something. That's another reason why I am not in academics nor do I do research. Patients also just weren't that sick. If you're an ER doctor, could you imagine the acuity if you just intubate 7.2% of patients in respiratory failure on standard oxygen therapy? That means these patients weren't that sick. I mean, the intubation rates for all comers in patients who are on HFNC in subsequent studies flirts with 30%. Please don't quote me on that number but I believe it to be accurate based on my prior research. I can just imagine how many clinicians would irresponsibly read through the abstract and say, HFNC is not good and just throw away the technology ignoring the benefits. Then you have to fight against their cognitive dissonance to make them change their practice. That's enough for today on this study. Thanks for checking it out.
A 🎩 tip to the authors

-EJ




Jones PG, Kamona S, Doran O, Sawtell F, Wilsher M. Randomized controlled trial of humidified high-flow nasal oxygen for acute respiratory distress in the emergency department: the HOT-ER Study. Respir Care 2016;61:291–299.

Link to Abstract

Link to FREE PDF


Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

My Amazon Store

Tuesday, September 10, 2019

BiPAP (NIV) vs. High Flow Nasal Cannula


High-flow nasal cannula oxygen therapy in patients undergoing thoracic surgery: current evidence and practice

Always give credit when credit is due and cite your sources. The article below isn't free, but if you can get your hands on it, it has some really nice tables. In particular, there is one table where they compare non-invasive ventilation to high-flow nasal cannula with regards to comfort, airway pressure and PEEP (see more on my post about that yesterday), anatomical dead space, CO2 washout, mucociliary function, pulmonary effects, extra pulmonary effects, skin breakdown and sores. It's worth checking out if you have access to this journal.

- EJ




Link to Abstract

Wittenstein, J., Ball, L., Pelosi, P.; Gama de Abreu, M. (2018). High-flow nasal cannula oxygen therapy in patients undergoing thoracic surgery. Current Opinion in Anaesthesiology, 1.

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

My Amazon Store

Monday, September 9, 2019

High Flow Nasal Cannula: Does it generate "PEEP"?

Please note that I have sorted out this issue and the following rant is a rant on my thought process leading up to my eventual resolution. 

I was trained, or maybe even made it up in my head, that for every 10L of flow increase on the HFNC, you get 1cmH2O of "PEEP". Is this accurate? The short answer in my opinion is no. At least not the way you're thinking about it. I've been digging pretty deep into the topic because although much data is suggestive of it, but I can't find something that I can clearly understand. Maybe it's just my lack of intelligence or lack of direct pulmonary training. Positive end-expiratory pressure (PEEP) is defined by UpToDate as the alveolar pressure above atmospheric pressure that exists at the end of expiration. Therefore, we need to look at alveolar pressure directly. In particular, we need to look at extrinsic PEEP. Without a closed system, we cannot obtain that data. I have run into several papers cited below that discuss methodologies used to estimate what PEEP should be in the HFNC system. The 2009 Parke study looked at the mean nasopharyngeal airway pressure and deemed it to be 2.7cmH2O with a flow of 35L and the mouth closed. That's not the alveolar pressure. The Corley study utilized electrical impedance tomography along with a transducer placed nasally that ran down into the esophagus that measured the airway pressure. With the flow in the study between 35-50L on the HFNC system, the authors found that there was an increase in the airway pressure by 3cmH2O. Is this what's being considered as PEEP? Lastly, Parke performed another study in CVICU patients where she and her team measured nasopharyngeal pressures at 30L, 40L, and 50L, and concluded that the HFNC system provided 3-5cmH2O of PEEP. I guess that's where the numbers I was taught came from. But in reality does that translate to PEEP? Do we just need to accept that we are comparing apples and oranges? Do we just need to change our language since we are just so comfortable of saying "PEEP" because we're used to it on our ventilators? Am I just going to have to delete this post after I am exposed as being a moron when a number of people just comment about how silly am I that I do not know this stuff? Why are we even trying to compare the two? We know that pharyngeal pressure is increased by the HFNC system. That's fine and dandy. Patients do well on HFNC when used in the correct setting. Plenty of data to support that. But this system uses flow rather than pressure and we are comparing apples to oranges. The three articles are all FREE! Links below.

Addendum: tonight is 9/24/19 and it's 4:34 in the am. I am currently working a night shift. I have run into additional data that has provided me with some perspective as to the whole PEEP/Paw discussion. Parke performed a study that was published in 2015 using Electrical Impedance Tomography where there was a marked improvement in the end-expiratory lung volumes. Then Frat, the main author of the FLORALI trial, commented on the mechanism of how this happens by stating that the large nasal prongs create a resistance to the exhaled air by continuously pushing high flow air and in turn this causes positive pressure. The issue lies when the patient opens their mouth. This could be highly variable. Anyway, I still take issue with the numerical measurement of it.

-EJ

Link to Abstract


Link to FREE Article

Parke R, McGunness S, Eccleston M. Nasal high-flow therapy delivers low level positive airway pressure. Br J Anaesth 2009;103:886–90.

Link to Abstract

Link to FREE Article

Corley A, Caruana L, Barnett A, Tronstad O, Fraser J. Oxygen delivery through high-flow nasal cannulae increase end- expiratory lung volume and reduce respiratory rate in post-cardiac surgical patients. Br J Anaesth. 2011;107(6):998- 1004.

Link to Abstract

Link to FREE Article

Parke RL, McGuinness SP: Pressures delivered by nasal high flow oxygen during all phases of the respiratory cycle. Respir Care 2013; 58:1621–1624.

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.

The primary source of compensation I receive for this page and Instagram work is via Amazon Affiliates. All this free education you receive is much out of the kindness of my heart but I also like to receive a check every month from Affiliate Marketing. No one likes to work for free. The best part is that it's of no cost to you. Here's how it works. 

You click on the link for Will Owens' awesome ventilator book here: https://amzn.to/2myFxYm and whether or not you purchase the book I receive a small commission for whatever you buy on Amazon for the next 24 hours at no cost to you. For every copy of the Ventilator book people have bought off of my affiliate links, for example, I have earned $0.85. I know it's not big money but it helps motivate me to keep on plugging along doing this heavy lifting in Critical Care. Thank you for supporting my work! 

My Amazon Store

Tuesday, August 27, 2019

High Flow Nasal Cannual vs. Conventional Oxygen Therapy vs. Non-Invasive Positive Pressure Ventilation

Can High-flow Nasal Cannula Reduce the Rate of Endotracheal Intubation in Adult Patients With Acute Respiratory Failure Compared With Conventional Oxygen Therapy and Noninvasive Positive Pressure Ventilation? A Systematic Review and Meta-analysis

I need help with this. Is it me or is this an apples to oranges study? I ask that because the authors compared high flow nasal cannula to conventional oxygen therapy and then they compared HFNC to NIPPV. Okay, the COT versus HFNC is an easy one to settle. Fewer people are going to be intubated if they’re on HFNC, all comers. But the caveats kick in when the authors compare HFNC to NIPPV which many of you know as BiPAP. My issue is because they included patients who were having acute exacerbations of COPD, acute cardiogenic pulmonary edema, asthma exacerbations, and ARDS in the HFNC vs NIV arm of the study. It is my opinion that that’s a bit ridiculous bc we know (and knew in 2017 when this study was published) that those patient populations more often than not need more support than what HFNC can provide. I will say there is data for HFNC in all those settings, but not enough to prove a benefit to NIV. Can you chime in below with your thoughts? I don’t think they should have looked at all comers for HFNC. Taking it by disease processes which other authors have done would yield actual real world results. These devices need to be carefully tailored to the patients you are treating. I’m more than willing to change my mind but I need help. Thanks.  

-EJ

Link to abstract

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Tuesday, July 23, 2019

High-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients after planned extubation: a systematic review and meta-analysis



Link to Article

Link to PDF

One of the dreaded things in Critical Care is to extubate someone and see that they’re not flying. It makes you question yourself; your judgement, assessments. It makes you self conscious. Will families may lose trust in you, and most importantly: are you causing harm to your patients? I’ve had just 6 reintubations in my 2 years out of training but that is considered too few as the reintubation rate should be 10-15%. Otherwise you’re not being aggressive enough. I don’t even check blood gases before I pull the tube. Needless to say, my kickass RT’s know that for the questionable pts, I want the #BiPAP or #HFNC at the bedside when we pull the tube. Sometimes hooked up and ready to go, sometimes outside the room to “ward off evil spirits”. I have a plan A, B, and C ready to go before I reintubate. My empiric data, otherwise worthless, shows that HFNC does help prevent reintubation. This meta-analysis says different. My bias, admittedly, says the conclusion has some limitations, and if you seek you shall find. This is an issue with meta analyses, the heterogeneity. You’re trying to compare apples and oranges regarding different studies and the authors did the best they could with statistical gymnastics that I don’t quite understand to make apple pie with an orange flavored crust. It just didn’t work out to show certain endpoints bc the included studies were just too different. Does that means that HFNC really doesn’t help avoid reintubations? Nope. It just means we need more data. A big 🎩 tip to the authors. 

Monday, June 10, 2019

High-Flow Nasal Cannula in Acute Hypoxemic Respiratory Failure: A Review of the FLORALI Trial

High-Flow Oxygen through Nasal Cannula in Acute Hypoxemic Respiratory Failure

I first shared this article in June of 2019 on Instagram when my account had a mere 2500 followers. Since then the amount of followers to my account have skyrocketed and I could not have done it without the help of each and every one of you who find value in what I do.
As an aside, many of you know I'm preparing a lecture on high-flow nasal cannula and non-invasive ventilation. This article is one of the landmark trials in the HFNC literature and it's worth revisiting in greater detail. After all, I wasn't taking articles apart in as much depth several months ago as I am now. The name by which this study is commonly referred to is the FLORALI trial, as in high FLow Oxygen therapy in Resuscitation of patients with Acute Lung Injury. Witty, huh? The authors had noted that there weren't any studies looking at non-invasive ventilation in patients who were in acute hypoxemic respiratory failure that were not hypercapnic. They went ahead to detail all the beneficial effects of HFNC which I have beat you all over the head with on this medium. They went ahead and designed a prospective, multicenter, randomized, controlled trial to see which worked best to avoid intubations and improve outcomes in patients who were in hypoxemic respiratory failure: NIV, HFNC, or standard oxygen therapy which I will herein refer to as SOT.
They chose to enroll patients who were sick, but not too sick. After all, you need to enroll patients and keep them safe at the same time. If you choose patients who are too sick, then clinicians aren't going to follow the study protocol. They had a strict protocol as well to intubate patients so that patients wouldn't be left lingering without being intubated. After all, there is clear data that if you wait too long to intubate, patients do poorly and there is increased mortality. They included patients who were hypoxemic with a PF ratio < 300, needing a flow of 10L, a PaCO2 < 45 (so no COPD exacerbation patients here) and no chronic respiratory failure. Asthmatics were also excluded, as well as cardiogenic pulmonary edema, use of vasopressors, and hemodynamic instability. They had other parameters but you can check out the article for yourself.
Patients were randomized at 1:1:1 for SOT (nonrebreather at flow of 10L), HFNC (50L of flow and FiO2 titrated), and NIV (pressure support titrated to obtain a tidal volume of 7-10cc/kg ideal body weight and a PEEP between 2-10cmH2O).
When you look at the characteristics of the patients enrolled, and they enrolled 310 of them, the vast majority had pneumonia with a predominance of community acquired followed by healthcare associated pneumonia.
The primary outcome was rates of intubation. There was no difference if you just look at the direct comparison p-value of 0.18. When you look at the patients who had a PF ratio less than 200, though, the patients with HFNC did MUCH better with p-value of 0.009. This is your indication, team! You have someone with pneumonia, don't put the on NIV when HFNC may work better!
Fewer patients died in the ICU if they were to receive HFNC versus the other two (p=0.047).
There was also improved 90 day survival in the HFNC group (p=0.02). This was enough info, and more in the article that you really should read for yourself, to convince many ED and ICU practitioners that HFNC is the way to go in this patient population. Check the article out for yourself!


- EJ






FREE FULL PDF with an account

Frat JP, Thille AW, Mercat A, Girault C, Ragot S, Perbet S, et al.; FLORALI Study Group; REVA Network. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med 2015;372:2185–2196.

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