Latest / Behind The Knife: The Surgery Podcast / Clinical Challenges in Burn Surgery: Inhalation Injury
Transcript
- audio3441419423 === [00:00:00] Welcome to Behind the Knife the Surgery Podcast. Today we're diving into one of the most complex and high stake scenarios in burn care inhalation injury. I'm Dr. Lauren Nosov from Grady Memorial Hospital, and I'm joined today by Dr. Kathleen Romanowski from uc Davis and Shriner Sacramento, and Dr. Victoria Miles from the LSU Health and UMC nor. New Orleans today, we'll tackle a clinical challenge evaluating and managing inhalation injury using two real world cases, discussing current evidence and ending with a few quick take home pearls. So let's jump right into our first case. For those of you that have done any level of burn care, this should sound pretty familiar. So you've got a call that we're getting a 55-year-old man with hypertension type two diabetes and a [00:01:00] 40 pack year smoking history. He's rescued from a house fire after spending a prolonged period inside evacuating his wife and of course his two cats. EMS finds him outside of the house covered in soot with about, they're saying maybe 35% TBSA or total body surface area burns. He's coughing. Maintaining his oxygen saturation on room air. So by the time he rolls into your trauma bay, EMS is able to tell you they don't have any concerns for concomitant trauma and that the patient was ambulating on scene. So Dr. Romanowski, what's next? So this sounds like a pretty bread and butter burn scenario. And you see soot, you see cinch nasal hairs, and everyone in the room starts thinking. Tube. But the real question is, does this gentleman actually require intubation right this second? Exactly. [00:02:00] The reflex is often to intubate early lead just in case. But we know from data, including your 2016 JBCR paper, Dr. Romanowski, that more than a third of patients transferred to burn centers arrived unnecessarily intubated. That's a lot of intubation that never needed to happen. Right. And in that study we found that many of those patients had no evidence of airway compromise, and some were extubated within mere hours after arrival. And we all know that intubation is not without its own risks. So when you encounter this patient in the trauma bay, you want to asbe their, assess their respiratory status, not just their physical appearance. Is the patient protecting their airway? Are they phoning normally any strider? These are the questions you wanna ask yourself. So it's really not all about soot in the air. It's the entire respiratory status. Exactly. Soot in the mouth or syn nasal hairs. [00:03:00] They're clues, but they're not equal to impending airway obstruction. What's far more concerning are progressive hoarseness, difficulty clearing secretions, mental status changes, or if the patient's developing increasing work or breathing. And something I always keep in mind is the burn size with 35% TBSA, we're anticipating a large volume resuscitation. That fluid load can worsen airway edema. So even if he looks okay now, we might decide to intubate before things swell if he's about to get a massive resuscitation. I completely agree. It's about anticipating the patient's trajectory. I'd perform an oral pharyngeal exam. And if you see mucosal disruption or blistering, then that's a high risk airway that you want to consider intubation early for, and remember that there are different types of inhalation injury. There's supraglottic injury and infraglottic injury. [00:04:00] Supraglottic injury, which is usually thermal, causes swelling of the epiglottis and vocal cords. That's what usually leads to stridor and obstruction. Infraglottic injury, on the other hand, results from smoke or toxic gas inhalation. This usually causes chemical damage to the airways and inflammation of the tracheal bronchial tree. The management and prognosis of these differ, so recognizing which pattern you're dealing with can be critical. Okay, so you perform an exam and note the patient reports hoarseness now and he has some blistering of his bcal mucosa. Now, what's your next step? Remember, we are anticipating having to do a large volume resuscitation. I would intubate this patient. In general, the most experienced provider present should intubate the patient due to their concerning airway. As with any high risk airway, you want to make sure you have the equipment and personnel available for a possible surgical airway. [00:05:00] Absolutely. So even though a lot of the times people coming in do just fine, it's the scary ones that get really scary. So in this case, it goes fine. Fortunately, he has an eight oet tube confirmed in proper position with end tidal CO2 and a chest x-ray Dr. Miles, what do you anticipate seeing on initial chest x-ray post intubation? Surprisingly, chest x-rays are usually normal just after inhalation injury. That isn't true later on, but if bronchoscopy is available, that's your gold standard for confirming injury. Right. Yes, that's what I tend to use. Flexible bronchoscopy within the first 24 hours is ideal. It allows us to grade the injury, although as a 2015 Walker review points out, the grading doesn't correlate well with outcomes. It's more about documentation and potentially guiding therapy. [00:06:00] I also emphasize to my team that these patients can deteriorate quickly. So even if we hold off on intubation, we keep airway equipment at the bedside and have the most experienced operator ready. This isn't the time for a trainees first tube. Some really good points. So in summary, assess respiratory status. Perform an exam. Anticipate edema from large volume resuscitation, at least for your larger burns. Use bronchoscopy within the first 24 hours of fable and have a low but thoughtful threshold for intubation. Right, and, and don't forget to evaluate for systemic toxicity. Inhalation injury is often associated with elevated carboxy hemoglobin levels from carbon monoxide or even cyanide exposure from burning plastics and synthetics. High flow a hundred percent oxygen is. Your first line therapy and if there's unexplained D lactic acidosis or altered mental [00:07:00] status. Hydroxycobalamin is the antidote of choice for cyanide, otherwise known as cyan kit, though I think it should be used cautiously as newer research has revealed in association with early renal dysfunction. Finally, we really can't overstate this mortality for patients with both burn and inhalation injury is much higher than for patients with burns of the same size, but no inhalation component. Recognizing and treating early truly changes outcomes in this situation. So with that said, we're gonna move on to case two, which you'll find similar. Different. So in this case, we have an 85-year-old man with non-small cell lung cancer who is at home on home oxygen at three liters per minute, and he was smoking when his oxygen ignited, causing a flash burn to the face. Also, a story we hear over and over and over again.[00:08:00] So, Dr. Miles, what's our initial concern here? So as a burn surgeon, this is a call that we get all the time, flash burn while smoking on oxygen. Everyone panics about inhalation injury, but the reality is this just really is not inhalation injury. This is really a thermal injury to the face and maybe to the upper airway from a quick flash flame. It's not smoke inhalation. There's rarely enough time or byproducts of combustion to cause true lower airway damage. Exactly. There was a 2025 paper out of Wake Force that looked at these cases and found that many patients didn't need burn center admission at all. If there's no airway compromise, they can often be managed as outpatients with local wound care to the face. Yeah, pretty much. This patient of case number two is never going to go the route of the patient in case number one. [00:09:00] Less. Of course, in the process of the flash burn to the face, they lit all their bedsheets on fire and all hell broke loose. So the big takeaway here is that while smoking and oxygen is dangerous, it doesn't automatically mean an inhalation injury, which again, like Dr. Miles, he said, doesn't necessarily mean they need inpatient and or burn center care. That's completely correct, but you really should look for airway edema. If the flash occurred with the patient having an open mouth, or if they are experiencing voice changes, it's very rare. It's not what happens in most of our cases, but you definitely want to check for those very rare cases, whereas a patient does have a more significant oral pharyngeal injury. And again, don't intubate prophylactically. If the patient's talking to you, if they're oxygenating, just let 'em breathe. These patients are often in stage COPD or [00:10:00] cancer patients. That's why they're oxygen dependent in the first place. And if they're intubated, they often will never be extubated. Honestly, I usually recommend my COPD. Smoking on oxygen, patients are treated more like A-C-O-P-D exacerbation with PO steroids and antibiotics as the flash burn can actually trigger A-C-O-P-D exacerbation. This is also a reasonable time to consider palliative care consultation with these patients so that you can have realistic discussions about what their goals of care are and whether considering oxygen, the home, oxygen therapy is the right thing for them. And we'll all throw in there some bonus discussion on smoking cessation. Though I think at this point in the game, we'll just try to have them not come back again with a similar incident, which I have seen. All of that is to say, hopefully we've cleared up a little bit of a common misconception. If you're caring for a patient like this and don't have access to a local burn center, it's a great [00:11:00] opportunity to consult your regional burn center for insight into the subtleties of management of these complex patients. So now that we've got that all settled, let's step back and hit some inhalation injury diagnostic pearls. Dr. Romanowski, how do you actually recognize a true inhalation injury at the bedside? I. So there are some classic clues. Soder, carbonaceous, sputum voice changes if the patient describes this subjective sensation of difficulty breathing and then mucosal erythema or ulceration. But again, it's not so much that there's a single finding that clinches the diagnosis, it's more about pattern recognition, plus thinking about the mechanism. And don't forget history. Actually, the first question I ask when a patient rolls into the trauma bay was, was the patient in an enclosed face? Mostly because if I do not have an airway emergency, I have time to collect my thoughts. With a [00:12:00] burn patient, usually a major burn patient isn't going to get very sick per se, in the first few hours after arriving, unless they have significant inhalation component. So wasn't an enclosed space. Was the, what was the duration of their exposure? That context matters. A small kitchen fire is very different from being trapped in a burning building for 10 minutes. Absolutely. What about grading systems? Again, do you use them? I do, but mostly for documentation purposes. The grades are from zero through four and they're based on bronchos bronchoscopic findings. But I don't really let it dictate my management. As previously stated, there's a review that was done by Walker that reminds us that there's actually little correlation between grade and mortality or ventilator days. Right. What guides the management of these patients? More is their clinical course. Is a patient improving or [00:13:00] deteriorating? Are secretions clearing? With that in mind, let's talk some therapy. So what's your go-to ventilatory approach once a patient is intubated? I treat it like a RDS, so low tidal volume ventilation, high peep. Avoid bear trauma. When I teach the residents, I call it the three Ps and a V strategy, so high peep proning, a short course of paralysis and low tidal volume ventilation. That's a great pneumonic. I would add that if the PA O2 or PA CO2 remains high despite those or remains poor, despite those strategies, we consider ECMO as a salvage therapy. Absolutely. And what about pharmacologic adjuncts? So this is where what we refer to as the ham regimen comes into place. It's heparin, albuterol and mCHEMIST nebulized Q six hours for approximately [00:14:00] seven days. Some people determine how many days based on their, their grading from their bronchoscopy. That's pretty much our standard of care in our unit. It's been shown to reduce airway, cast formation, and improve clearance. Yeah. Ham therapy is really one of the few things with decent evidence for benefit in inhalation injury. What about the, the big bad word of steroids? So for true inhalation injury, there's really no role unless you're treating a concomitant reactive airway disease. At the same time, they aren't, haven't been shown to reduce edema or improve outcomes, and it can actually increase your infection risk and worsen wound healing, particularly in patients with wound with burn wounds. Remember for carbon monoxide and cyanide toxicity, a hundred percent oxygen is your first line therapy. If you suspect cyanide toxicity due to a high lactate seizure-like activity or cardiac arrest, [00:15:00] hydroxycobalamin or CY kit is appropriate, but use with caution as acute kidney injury can result. Absolutely. Really good summary. What about outcomes? How does inhalation injury change? Prognosis, it's, it's huge. Again, mortality can be 15 to 19, higher, 15 to 19 times higher for the same size burn. Even if the TBSA is moderate inhalation injury dramatically worsens outcomes. And don't forget, they also require more fluid. It can be up to two and a half to three times the usual resuscitation volume. So you need to balance the extra fluid needed in a patient with an in inhalation injury with the risk of developing pulmonary edema, which is gonna make your ability to ventilate and oxygenate them harder. That's where close monitoring and titration are really critical over [00:16:00] resuscitation, worsens, gas exchange. I will say that that fact, the patients with burns and inhalation injury. The ones with inhalation injury require two and a half to three times. The volume of resuscitation has always perplexed me. I always ask the residents, can you name another condition in medicine where the lungs are sick? Where you say, let's give 'em a ton of fluids, right? So there's not a condition where that's the case. So. I think we all assume that when you have exposure to chemicals and superheat, exact gasses that you have released of some type of inflammatory cytokine or something that causes vasodilation, that leads us to then need to give more fluids. But I think that's one fascinating physiology fact about burns that I really, I can't wrap my mind around, but it's one of the reasons I wanted to be a burn surgeon. Absolutely. And I, I always wanna remind everyone there's a reason that inhalation injury made it into the modified B score, right? Forever and ever and ever. It was age and TBSA, and then the [00:17:00] more we knew, the more we realized that time and time again, presence of inhalation injury is going to play out as a significant predictor of mortality for all of the reasons that you both just specified. All of this is to say, what about long-term complications? So we got them. We got them through, but now what? Yeah, this can really be a challenge and patients can have a lot of long-term sequelae from their inflation injury. We can see chronic coughs, dysphonia trachea, or subglottic stenosis. Some of these patients even require airway reconstructions and then. They can just in general, never return. Some of them never return to their baseline level of functioning. So that can be especially hard in people who've had workplace injuries that have led to this. In short, these patients require long-term multidisciplinary follow-up to make sure that they do the best they can after their injury. And don't forget the psychological component. PTSD, anxiety, even depression, are common [00:18:00] after airway injury and prolonged intubations. Along the vein of prolonged intubation. Dr. Romanowski, when do you start thinking about tracheostomy? This is a little bit of a challenging question in the burn world because the burn literature does not provide a clear answer. This is definitely an area for those of you who are listening, if you want to do some research to look at. Each patient scenario is completely unique. It really depends on their burn size. Do they have significant facial or neck burns that are gonna make it hard to keep a endotracheal tube in place? Do you anticipate a prolonged intubation because of how bad their inhalation injury is? If any of these are true, we often will follow the trauma literature and perform tracheostomy early in the patient's course. This facilitates pulmonary hygiene and stereo bronchoscopy and also allows two securement away from where you may need to do skin grafting to their face or neck. Yeah, and that [00:19:00] initial ET tube size matters. I think the initial inclination of folks is to grab a, grab a smaller ET tube because they anticipate airway swelling. However, it's your first intubation that's. The time to secure a reasonable size tube where we'll have excellent bronchoscopic access. So we need to retrieve casts out of the airway or any sloughing of the airway. So we really shoot for a seven and a half to or an eight OET tube initially to allow for that good bronchoscopic access. Yeah, definitely don't underestimate. I have had experienced experience an anesthesiologists look at the airways of some of our worst inhalation patients and declare them the worst airway they've ever seen in their entire career. Never wanna be the person who's impressing us. So again, make sure that first intubation is done by someone who's experienced, knowing that there will be serial reevaluation as clinically indicated. So, although we're all really [00:20:00] excited by this topic, I do think that we probably need to start wrapping up today's Behind the Knife Burn Clinical Challenge on Inflation injury. Thanks for joining us, everybody. We hope this helps guide your next airway decision making scenario when a burn patient arrives to your center and as always dominate the day the day.