Invictus Reviews

Submersion, Event! and End of the Pod (for now)

• Mel Herbert

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We reframe “drowning” as submersion incidents and lay out a simple path from shore to safe disposition. Hypoxia drives arrest, observation prevents misses, and ECMO has a clear role when ventilation fails or hypothermia persists.

• replacing drowning with submersion incidents
• hypoxia as the primary cause of arrest
• selective C‑spine precautions based on mechanism
• ECMO for refractory hypoxemia or hypothermia
• normal chest X‑ray can mislead after aspiration
• strict four to six hour observation window
• discharge only if fully asymptomatic with normal vitals and exam
• admit for any symptoms, abnormal gases, dysrhythmia, or abnormal imaging
• use NIV for symptomatic, alert patients; intubate if needed
• avoid steroids and routine antibiotics; exception for sewage exposure
• active rewarming as a core treatment step
• board strategy: read stems literally and match management to symptoms

Our oral board review course is going to be out soon, like really soon. The written board review will be delayed until early next year; we’ll restart a new and better podcast with more people in the Invictus part of things—stay tuned.


SPEAKER_00:

Uh first of all, we're gonna talk about submersion injuries. Jesse Warner, great talk. Our uh oral board review course is gonna be out soon, like really soon. It's going through beta testing right now. Um but the written board review we've determined is gonna be much bigger than we initially planned. And because of that, it's gonna get delayed. It's not gonna come out until early next year. We've got a bunch of new faculty involved, and it's gonna be much better with emphasis, with podcasts, with live events, with uh written summaries, and with m multiple choice questions, and maybe even some other bigger stuff to tell you about soon. And there's also the recognition that I'm just not getting to this frequently enough because of uh my other work on MRAP and on the pit. So um what I'm gonna do is gonna make this the last one of the free podcasts, and we'll just leave it here, sitting out here in the universe, and then we're gonna restart a new and better podcast with more people in the Invictus part of things when that gets booted up early next year, we hope. Um and it'll be uh much uh more exciting than what I've been doing. But some of these lectures give you an idea of where we're going and some of the faculty. So let's talk submersion injuries, and before I start the lecture, let me summarise this up front. Uh there's uh not drowning anymore. There are submersion events. And the way I think about it is there's events with a patient who has symptoms and a patient who doesn't have symptoms. If they don't have symptoms and they don't have symptoms or signs, for four to six hours they get to go home. Nothing to do. But if they do, then what you do depends on the level of how sick they are. If they're a little bit sick, a bit of oxygen. If they're sick in non-invasive ventilation, if they're really sick, you might have to go to ECMO or intubation. But the key thing is you watch them for a while, symptoms versus no symptoms. Jesse will explain. Herbert out. I'll see you on the other side when we get Invictus out and rolling. I might jump on here one more time just to say when it's actually uh formally live, but for now, don't expect any new of new ones of these while we put our resources over onto the actual Invictus site. Herbert out.

SPEAKER_01:

I'm Jesse Werner. Let's talk about submersion incidents. So remember in the past, for those of you who who may or may not remember this, they used to be called drowning, and you know, we use that word commonly when we're talking to our friends. But when it comes to the board exam and being really specific in emergency medicine, drowning is gone. Now everything is called submersion incidents. It's just a little bit more specific. If you get answers that talk about drowning or near drowning or dry drowning, just know that those are antiquated terms. We're not really using those anymore, and so they are probably not correct. Some key points. Cardiac arrest in the setting of drowning and submersion incidents is predominantly due to hypoxia. That's the big problem here is hypoxia, right? The person inhales water, gets into their lungs, they have hypoxia, and that is usually what leads to cardiac arrest. There are other things that can happen in submersion incidents, specifically if someone dives into shallow water, they can hit their head and end up with a cervical spine injury. C-spine immobilization is only necessary if there is a specific concern for associated traumatic injury. So when they're describing a submersion incident and they're saying this person was found in the lake, or they describe someone who was witnessed having a drowning episode and submersion injury, you only need to worry about C-spine precautions and treating this like a trauma patient if there's some kind of history of that. And they will usually provide that to you in the question stem. What about ECMO? So this can be beneficial in patients who have a severe lung injury or difficulty with adequate oxygenation despite being on the ventilator and optimizing that ventilator, or they have refractory hypothermia. So let's say it's the East Coast, it's winter, someone has had a submersion incident in a in cold water in the winter and you just cannot warm them up, or the patient has cardiac arrest and you're having a hard time getting them back. That's when you're going to think about ECMO and activate your ECMO team. The initial chest radiograph, so you get a chest x-ray, does not always correlate with the patient's blood gas, their clinical outcome, or their disposition. In other words, don't let the boards fool you. They might say this person had a submersion incident, and they will show you a chest x-ray that looks beautiful. It's totally normal, but the person is having symptoms. They're having respiratory symptoms, or they have abnormal arterial blood gas, and you can see that they haven't oxygenated well. Even if that chest x-ray is normal, that is a bad sign. So don't let the chest x-ray fool you. It does not always correlate. Don't assume that a patient who comes in with just mild symptoms, they have a little bit of cough, a little bit of shortness of breath, but they look pretty good. Don't assume that they're going to improve. They can decompensate. And one teaching point here is if the patient has symptoms, they really can't go home. You're going to admit all patients who have vital sign abnormalities, that's a given. Chest x-ray abnormalities, respiratory symptoms. So they have symptoms, or they have a blood gas abnormality. Anything that shows that something is not right, that there is something abnormal here after the event, that person gets admitted. Chest x-rays are not required for asymptomatic drowning patients. So not everyone who comes in after a submersion injury needs a chest x-ray. If they're alert, if they're breathing on their own, if they have no symptoms, like let's say they were underwater for a brief period of time, they were pulled out. Usually they're going to describe this as a child. The child went under, they were pulled out, they can't, they were brought out of the water, and they're doing great now. They have no respiratory symptoms, they're wide awake, they're breathing on their own, they don't need supplemental oxygen, they don't have a cough, they don't have any shortness of breath, they're totally asymptomatic. You do not have to get a chest x-ray in that patient. What about patients who can go home? So the only way you're going to consider discharge is if the patient meets this criteria. You've observed them for an adequate period of time. It's a long time. We're talking about four to six hours here. So this is testable. They might describe a patient who looks really good and they say, like, when can I discharge this patient? Or what should we be considering? An observation period is absolutely necessary and it needs to be four to six hours. Once you have observed that patient for the adequate four hours or six hours, they then have to meet all of the following criteria. No cough, no respiratory complaints. Even a simple cough counts as a respiratory complaint. No vital sign abnormalities, no physical exam abnormalities, right? So they need to be not to kypnik, not have any concern that they had a traumatic injury. So no physical exam abnormalities, and no radiographic abnormalities. If you get that chest x-ray and it's abnormal, even if the patient looks good, they can't go home. Symptomatic patients get admitted. So when you see a patient who has a submersion injury and they're asking you what your discharge plan is, let's say you've started with the four to six hour observation period, they continue to be symptomatic, that person is being admitted. So this is witnessed apnea at any point. They weren't breathing. Any cardiac dysrhythmia, they had hypoxemia or an abnormal chest x-ray, those all count. That person needs to be admitted. How do we treat a submersion incident? So the person has gone underwater, they're come back up, there's different things, you're going to address the patient in front of you if they're awake and doing well or a little bit symptomatic. Let's say they're having a cough, they're a little short of breath, but they have a good mental status, you're going to reach for non-invasive positive pressure ventilation, something like BIPAP. You always prioritize the airway. If the patient is really sick, they've been intubated, they continue to have refractory hypoxemia, you can't get their temperature up, that's when you're thinking about something like ECMO and activating the ECMO team. Do we need antibiotics? This is a question that you're definitely going to get tested on, and it comes up in real life. They're going to say, do we need to give this patient antibiotics after they've had this submersion incident and they've been after they've had a drowning? Do we give antibiotics? No, you do not need to give antibiotics. What about rewarming the patient? Yes, always. So remember, warming is part of the treatment. You're going to make sure that you've prioritized the airway, you're going to make sure that they're warm. And you're going to consider other injuries like trauma. Did the person hit their head when they went into the water? Are we concerned about a C-spine injury? Is there any sign that there's trauma involved? Do not give the patient steroids, not needed. And again, no prophylactic antibiotics unless there is one caveat. If it's super contaminated water, and I'm talking about like sewage. So if the person fell and drowned in sewage, then you can give antibiotics. But most of the submersion injuries that we're talking about, where it was a lake or it's the ocean or it was a swimming pool, you do not need to give antibiotics. So how are they going to test you on this? They're going to give you a scenario and then you need to decide on the management and the disposition of that patient. And it all comes down to those signs and symptoms that we talked about earlier. So you need to know the indications for non-invasive positive pressure ventilation. That's a great choice if they're having respiratory symptoms, but they have a good mental status. You're going to think about those indications for admission. Remember, observation is crucial. Everyone gets observed for about four to six hours. Think about those patients who might be eligible for discharge. We went through that list. Basically, they have to be totally asymptomatic, and their labs and imaging have to be good. And then remember, you don't need to give antibiotics. So let's go through a question together. Here, a 10-year-old child is rescued from a swimming pool after being submerged for approximately one minute. That's a pretty long time. He arrives in the emergency department awake, alert, and breathing spontaneously. He denies coughing or difficulty breathing. His physical exam is normal and his vital signs are normal. What's the most appropriate management? Remember, on the boards, every piece of information that they give you is absolutely critical. If they're leaving things out, they mean to. If they're telling you that a patient looks great, they mean that. So you don't have to assume that you're missing something. They're telling you everything you need to know. This person has no symptoms and no signs. They're doing great. So what's the appropriate management? A, discharge the patient home. B, obtain a chest x-ray and an arterial blood gas level. C, observe for four to six hours before considering discharge. D start prophylactic antibiotics. What are you thinking? C, observe for four to six hours before considering discharge. Let's just go back over these answers. Remember, you never discharge a patient home without that observation period. So you know that's part of the right choice. What about this chest x-ray and ABG? Well, this person's completely asymptomatic. We already said if the person is doing well and they don't have respiratory symptoms, you don't have to get a chest x-ray in every patient. And we said you don't need prophylactic antibiotics either. This person did not drown in sewage. So the answer here is observe for four to six hours before considering discharge. If they had described this patient as being symptomatic at all or having any abnormalities, this person would again be admitted. Here's another question. A 35-year-old male is pulled from a lake after a near-drowning incident. Now, I do want to say, near drowning, like I pointed out, is an antiquated term, but the boards are not always 100% up to date. And so you might see it written here. We know what it means. I just want you to know that it is not a term that we're using very much anymore. The patient is comatose and hypoxic, despite high flow oxygen, and his chest x-ray shows diffuse bilateral infiltrates. His ABG shows severe hypoxemia. After intubation and ventilator optimization, his oxygen saturation is still 85%. What's the best next step? A start broad spectrum antibiotics. B initiate extracorporeal membrane oxygenation or ECMO. C start steroids to reduce inflammation or D perform immediate chest tube placement. A couple things I want to point out here. On the boards, they love to try and confuse you with words and abbreviations. So they probably would write extracorporeal membrane oxygenation without putting ECMO in parentheses. And we all just think of ECMO. We're not often writing it out or thinking of the full definition of that term. They try and trick you with things like that. So make sure for any abbreviation, you know what it actually means. They might just write extracorporeal membrane oxygenation without the ECMO. And you need to know, oh yeah, that's ECMO. Okay, so put that together. So what's the right answer for this patient? So they're pulled from a lake, he's comatose, he's hypoxic, he has abnormal chest x-ray. We know for one thing this person is definitely not going home. Not only that, they've been intubated, the ventilator has been optimized, they're still hypoxic. What did we say is the treatment for those patients who have that persistent hypoxemia or they're persistently hypothermic? Like you've done everything you need to do and they're still not getting better. There's really only one right choice, and that is the ECMO, initiate extracorporeal membrane oxygenation. So again, this is indicated for severe hypoxemia that is refractory to ventilator optimization and oxygen support. We talked about antibiotics are not necessary here unless you really think that they've fallen into a sewage. Steroids are not recommended in the treatment of submersion related lung injury. A chest tube is not indicated. There's no pneumothorax or other signs of a traumatic injury that would require a chest tube.