Episode 4.0 – Perimortem C-Section, Procedural Sedation and Airway Pearls

Welcome back to the Core EM Podcast, core content for anyone, anywhere and just in time. This is Swami and this month our conference is focusing on airway and anesthesia as well as procedural sedation. We started off this week with a joint conference with Trauma and OB discussing Perry Mortem C-section. We're going to start there and then we're going to end the cast with a mini interview with Ruben Strayer from the EMupdates.com blog and discuss his talk on airway nightmares. Alright, so let's get to the core content starting with Perry Mortem C-section. We discussed a hypothetical case here and we're lucky enough to have our consultants from Trauma and OB present for the discussion. There were three big take home points from my perspective. Number one, throughout resuscitation focus on mom, not the baby. Resuscitation of mom is the only way to resuscitate the baby and a Perry Mortem C-section can almost be thought of as a resuscitative historotomy. In the Perry arrest and arrest phase, the distended uterus can decrease venous returning compromised the lungs by pushing up the diaphragm. If you can, sit the patient up or put them in reverse trendellanberg to decrease pressure on the diaphragm. You can displace the uterus, the left lateral, to take pressure off the IVC and increase venous return. The classic teaching is that you should almost put a ramp under them so they're in the left lateral de-cubidist position, but that's going to make all of your other interventions more difficult. Instead of that, just grab an extra set of hands, usually a med student, and have them displace the uterus off to the side. Now for the C-section itself, the traditional teaching is that at 24 weeks is when you should be thinking about doing this procedure because that's when the baby is viable. But again, we're focusing a little bit too much on the baby here. If you're not sure about gestational age, but you think the size of the uterus is compressing the IVC, go ahead and do the C-section. Any gravid uterus over 20 weeks is going to compress the IVC, and so relieving that compression is going to auto-transviews mom. The best incision is a long vertical incision to gain access to the uterus, and this procedure should be initiated immediately upon arrest of the mother. Delivery should try to occur within 4 minutes of arrest in order to maximize the outcome for the baby. But again, remember, our focus is resuscitating the mom. Now one of our faculty members, Celil Bundari, gave a great blast talk on this topic, and it was featured on the M-Crit website. We'll put a link to that in the show notes, but you can also just Google M-Crit and Perry Mortem C-section, and it's going to be the first thing that comes up. Our next talk was one of our PGY2 residents on procedural sedation. This was a basic overview focusing on setting up for sedation to the preparation phase, medications, and monitoring. Now the hallmarks of procedural sedation in analgesia, well it's right there in the name, sedation, analgesia, and dissociation from a painful or challenging procedure. It should be humane, safe, and controlled. The first and most important step is preparation. If you haven't prepared to fail, then you fail to prepare. This is really the key. In order to know how to prepare properly, we strongly recommend using a checklist. This is going to ensure that you don't miss any steps. There's a great procedural sedation checklist on Ruben Strayer site, EM updates, and again, we're going to drop a link to that in the show notes. During preparation, you should consider if the patient is simply a bad candidate for ED procedural sedation. Some patients simply may need the OR and general anesthesia. A lot of this is going to be based on the patient's comorbid conditions, the exact procedure you're doing, and a number of other factors. If they're poor candidates, consider getting them to the OR for the procedure. If you can't do that, so there's no OR available to you, then you should consider intubating the patient for the procedure, and then you can always extubate them when you're done. There's a lot of different medications that we can use for procedural sedation, and that's sort of beyond what we can discuss on the podcast. I'm just going to give you a quick couple pearls from this talk. Propophales commonly used, but just remember, there's no analgesia with propophal. Hypotension and hypoventilation are common, but short live. They rarely require more intervention than simple airway repositioning, maybe a couple of BVM breaths on top of that. Fentanyl and Versaed is a tricky combination because both of these medications can cause respiratory depression, and people respond irregularly to the doses, so it's hard to predict how much they're going to need. Hymenin is obviously another option, and so much out there in the foam world on this. Ketamine keeps the airway reflexes intact, and it doesn't cause hypotension in and of itself. Nausea-invomiting can occur, and you do have to consider the emergence reaction that can occur, but that's easily treated with some benzodiazepines. Give the ketamine as a slow push over 30 to 45 seconds, because it can cause a brief, but impressive, episode of apnea when it's pushed fast. We discussed a little bit about ketifol here as well. There's some potential advantages of both drugs in combination because it counteracts the individual side effects that you see with each drug. There's a lot of literature on this, but nothing really conclusive showing that ketifol is a better drug than one or the other. Finally, we discussed oxygenation and N-title CO2. N-title CO2 monitoring really brings up issues of oxygenation and ventilation. It's possible to have adequate oxygenation while ventilation is compromised. If this happens, you'll get a significant increase in CO2 and resulting acidosis while O2 can remain the same. Let's take the situation where you don't have N-title CO2 available. In this case, you monitor hypoventilation by visual inspection and keeping an eye on the oxygen saturation. That O2 stat is going to be a late alarm for hypoventilation because there's going to be a lag in the desaturation to when you see it on the monitor by about 30 to 60 seconds. Basically, what you see on the monitor is a look to the past. If you supply additional oxygen in these patients, your alarm will be even more delayed. You'll miss hypoventilation for a longer period of time. This is why we don't usually add supplemental O2 if there's no N-title CO2 monitoring going out of the same time. If you have an M-Rap subscription, there's a great discussion on this topic from Rob Orman in Scott Wyingar back in April 2015. Now if you do have N-title CO2, you can continue to give supplemental O2 during the procedure because you're going to have the N-title CO2 to give you an early warning. For the final part of this podcast, we're going to bring on Ruben Strayer who gave a great talk on airway nightmares. Ruben is an EM physician at Elmhurst Hospital as well as with us at NYU Bellevue. Ruben runs a great site focusing on a lot of issues related to airway and procedural sedation. Ruben, welcome to Corey M. Thanks, Anand. There's nothing I would rather be doing right now than talking to you. So I thought, instead of me discussing the great take on points from your talk, we'd have you on and let you discuss them. Let's start off by stating that challenging airways come in two flavors according to you. And I like this differentiation. Anatomic challengers versus physiologic challenges. It's a nice way to think for an emergency physician. Yeah, we run into a lot of trouble by applying broad terms to granular issues. And one of my pet peeves is the phrase "intubated for airway protection." If you didn't know better, you would think that every time we insubate an emergency department and we intubate for airway protection, the asthmatic who's going downhill, we intubate it for airway protection. I'd sell this old lady with a bilateral pneumonia, I'd intubate her for airway protection. No. Most of the time we intubate in ED is not for airway protection. It's for other reasons. And when we use terminology poorly, like that, it confuses people. And in this case, it confuses the reasons to intubate, which is a really important concept that is poorly understood by a lot of junior learners in emergency medicine. And so it is with difficult intubations. There are a variety of ways that intubation can be difficult. And we do a disservice to our trainees and ourselves when we lump all these problems together. So I break them down. Anatomic difficulty is when the cords are hard to visualize or the tube is hard to pass. And physiologic difficulty is when you only have a very brief time after induction to intubation before the patient crashes or the patient is slightly to crash around intubation even if you do it quickly. Yeah, I love that. I think we do lump a lot of things together. It's sort of lumping all CHF together, all PEs together. These are fraught with difficulties because the diseases are different. And I think challenging or difficult airways, there's a lot of differences from patient to patient when you see that. From that starting point, you go into sort of subcategories within each of these. So let's start with the physiologically challenging airway. And you talk about number one, the patients who have a high O2 deficit, but they're calm. So what were your tips here on dealing with these patients? Right. So the most common physiologic difficulty we face in a medicine is the patient with the high oxygen deficit, meaning that they have a huge AA gradient. They're saturating less than 95% on high high flow oxygen, which means that as soon as you induce and paralyze, this saturation is going to drop like a rock. So the mistake that I see is to try to fix the hypoxia quickly by like throwing down to the right weight or approach. These patients is to maximally pre-oxygenate them, which means nasal cannula underneath non-invasive ventilation at 100% of high O2 with high peep. And after you induce, we want to do a jaw thrust to keep the airway paint as the patient loses muscle tone so that apnea oxygenation can proceed. And you want to have an LMA ready at bedside out of the package, free lubricated, so that if laryngoscopy doesn't quickly succeed, you can immediately place the LMA and re-oxygenate. I actually abandoned vag mass ventilation during intubation and favor of LMA ventilation a few years ago. It's a much better technique and it's especially important in this scenario. way to pre-oxygenate them to give us the most time to secure that tube. And I think non-invasive is a great way to do this up front. You know, put that non-invasive over the nasal cannula. Get them up as high as you possibly can to make your intubation easier. From there, you move into sort of the 1B category. So it's the patient with a high O2 deficit, but they're not so calm anymore. They're agitated and so they're kind of fighting you on your pre-oxygenation. Right. So the patient who's too agitated to be pre-oxygenated is sort of a slightly separate category. It could be from hypoxia or could be from intoxication or psychiatry or whatever. But I'm talking about the patient who's ripping off his oxygen for agitation. And they're particularly scary to manage because it seems like he need to RSI these patients to control them, but doing RSI without preparation and pre-oxygenation is really dangerous. So Scott has given us a real winner with delayed sequence intubation where you push a dissociative dose of ketamine so that the patient becomes unconscious, but it's still breathing, which means that you can now properly prepare and pre-oxygenate. And then once you have everything ready, patients will pre-oxygenate it, push your paralytic and innovate much more safely. You know, I don't want to get too much into the topic of DSI because Scott does a great job in his podcast discussing it and we'll put links to the show notes for that. Now from here, you go to the patient who has a high ventilation deficit. So what do you mean exactly by that? Yeah, the high ventilation deficit is the patient who is profoundly acidemic. So their serum pH is less than seven. And so these patients rely on huge minted ventilations to keep their serum pH in a range compatible with life. So just like with the high oxygen deficit patients, these patients will be compensated when you paralyze if you're not careful. Unlike the hypoxic patient, though you don't have any warning. We don't have continuous pH monitoring, like we have pulse oximetry. So you don't know that their blood is turning into battery acid while you're trying to get the perfect view of the cords they just arrest. So the key is to hyperventilate these patients with non-abasive prior to induction and have your LMA ready for immediate ventilation if needed, just like in the high oxygen deficit patient. And also remember to hyperventilate after intubation. We are really bad at this. The patient is breathing 40 to 4U induced paralyzed. They probably need something like that after you put the tube in. Remember that the arterial carbon dioxide is at least as high as the end tidal, but can be much higher. So check your blood gase early and often. And an evolving airway strategy to consider in patients who don't tolerate apnea is to not make them apnec. You can use ketamine to induce and do a ketamine only intubation, what I call ketamine supported intubation or KSI with no paralytic. And this keeps the patient breathing during larynx osteopenia. I think we often do exactly what you said. We intubate these patients, the DKA air who looks real sick and we don't mimic their respiratory physiology from before they coded. They're doing a good job keeping themselves alive and then we put them on a vent. We paralyze them. Their CO2 skyrockets, their acidosis gets way worse and they code. So the idea of awake intubating them sounds great. If you're not comfortable with that, then I think the idea of just mimicking that respiratory physiology afterwards is going to be the key. Okay, so the last physiologically difficult group that you talk about is a group that has a high perfusion deficit. Yeah, so the patient whose blood pressure is in the toilet. These patients love to arrest around intubation and the right way to manage them is to resuscitate before you intubate. If you can't, with fluids, vasopressors addressing whatever is causing the problem with blood antibiotics, paracardiophantesis, whatever. I think the right way to use preserves in this context is not as bold as it's been described, but as a drip, I like to put 1 milligram of epinephrine into my leader of normal sitting that's already hanging and boom, I have quick, happy drip. The highest risk, high perfusion deficit patients are the ones with no mental status. Any induction agent in this context is going to act as some patholytic and worsening situation. So if the patient is obtunded, don't use an induction agent. You don't need it and it's going to cause harm. Do a parolytic only intubation or a awake intubation, quote unquote, awake intubation, what I call a no SI. And when you get the tube in, fact slowly and gently to avoid that abrupt transition to positive pressure that causes the drop in preload and blood pressure. If you do have to go forward with RSI and a really hyper perfuse patient, dose your sedative low when you're parolytic high. Yes, there's a great pearls. The one that I think is really important is how you dose those medications. You know, whatever drug you give them, whether it be propyl, whether it be ketamine, they're going to drop their blood pressure. So it's not about the drug, it's more about the dose. And again, this idea of the parolytic only, you'll see a lot of people that will sort of, you know, scoff at you. You're going to leave the patient paralyzed and awake. It's like, yeah, but I'm also going to leave the patient alive. And that's an important thing. So your primary goal in these patients is to keep them alive. If you can also keep them alive and keep them from remembering the incident, great, that's a bonus, but it's not the most important thing. So from here, you moved into the trauma airway, which is sort of a little bit of a meld of the physiological and the anatomically difficult airways. What were the big pearls on this one? The main point I want to make around trauma airway has to do with the baseless tradition of manual inline stabilization. So if you are having an easy time with the debate, I don't care if you hold manual in line stabilization or tickle your patient's feet or sacrifice a med student at the altar of the spinal injury. God, but if you don't like your view or if you're having a hard time putting the two through the cords, release manual inline stabilization and mobilize the head and neck. It is dramatically more likely that a badly interpatient has a brain injury compared to a C-spine injury. And even if there is an unstable C-spine injury, the likelihood that you're going to cause harm by mobilizing the head and neck is very low, where the likelihood that you will cause harm to the brain and your patient by having trouble intubating that patient is very high. So if you're having trouble intubating release manual inline stabilization and optimize your view, less common scenario is the really bloody airway, but it's a special scenario that's really important because a bloody airway can be a big, big problem. In this case, have your friends help you out with two suction, suction on either side. Those are the keys to the trauma. Inline stabilization, not really that necessary. You know what we know is that hypoxia kills trauma patients and hypoxia and hypercarbia, both worsen the brain injury that's already there. What we don't know is whether inline stabilization makes any difference. I don't think it's a very common scenario where the inline stabilization blocks you from getting the tube in, but if you can't get it in, just get rid of it and move forward with the tube. Exactly. Now finally, you discuss the pure anatomically difficult airway. And I love this. You really differentiate between VL and DL and kind of take the people to task who use those terms. So how do you think about these two modalities? Yeah. The conventional way that we use the term difficult airway, I've co-opted term anatomically difficult airway, meaning that you have trouble see the chords. And the main point around anatomic difficulty is that you have to be ready for it every time because you are not going to be able to predict it. And I mentioned a series of 188,000 Danish anesthesia cases that was recently described where, in this series, 93% of them, and 93% of the difficult airways in that series that the difficult airways were unanticipated. So you have to be cognitively and materially ready with a Plan A, B, C, D every time. And it's definitely worthwhile to do a difficult airway assessment if you have time because if you conclude that laryngoscopy is likely to be difficult or possible, you can choose alternative strategies to RSI, different forms of awake intubation, including KSI. And you can incorporate a double set up into your approach, meaning that your partner is standing at the patient's side with a scalp on her hand, ready to do a surgical airway. It's a need arises. Now with regards to VL and DL, if you're good at intubating with a hyperangulated blade, which is a somewhat different skill than using a traditional laryngoscope, you are going to be able to intubate just by everyone. But if you're not experienced with a hyperangulated blade, you are probably better off starting with a standard geometry traditional laryngoscope if you anticipate difficulty because the time to figure out tube delivery is not on difficult patient. That's a pretty incredible number first off with that 93%. These were anesthesiologists in the OR who had time. 93% of their difficult airways, they could not expect going into them. I think that's going to be even worse for us because we have so little time to make that assessment. So we should just assume that every airway is going to be challenging and prepare for them that way. And that way we won't be surprised. As far as the VL DL thing, I think the important thing here was that there are different kinds of VL and the standard geometry video laryngoscope is the way that we should be starting with all of these patients. It gives us the best chance for success because we can, especially in a training institution, the resident can have backup from the physician, the attending physician, to see what's going out at the same time. Yeah, that's exactly right. I think that if we're going to choose a default plan A for our most of our interventions, it should be a video laryngoscope with a standard geometry blade and that gives us sort the best of both worlds, meaning you can do direct or video-during gossipy using the same blade. And in the ideal scenario, if you're having a tough time with a standard geometry blade, you can hot swap it to a high-ranked-lated blade using a bunch of different video-duringoscope systems out there. So, Ruben, do you have any other take-home points before we wrap this up? Yeah. Well, when we think about our usual airway strategy, like I said, come up with your plan A, B, C, D every time. And it doesn't matter so much what your plan A, B, and C is. There are as many plan A's, B's, and C's as there are patients, providers, and environments. The key is that you're ready with a plan B and a plan C. If you're plan A and plan B fail, that's what airway expertise is all about. Yeah, so it's like Rich Levitan says, "If you failed to prepare, then you've prepared to fail. You've got to have all your backups in line." Now, if any of these topics are a little bit difficult to understand on the podcast or you're not quite getting it or you need more reinforcement, I strongly encourage you to go over to Ruben's site, emupdates.com, where he's got a ton of information on procedural sedation and airway. And actually, Ruben, you just posted a great 10-minute screencast, discussing VL versus DL. And again, more accurately, standard geometry blades versus hyperangulated blades. So again, check that out. I think it's a really great resource. Ruben, thanks for being on CORE-EM. Thanks for all of me. The pleasure was mine. All right, guys. So that's going to be it for CORE-EM. For this week, CORE-EM is core content, emergency medicine for anyone, anywhere, and just in time.