PHARM Podcast 23 – Mr EmCrit and the DSI chronicles from Dr. Minh LeCong’s great Pharm: Prehospital and Retrieval Medicine. This podcast is just as valuable as #137 [next paragrph]. In Podcast 23, Dr. LeCong interviews Dr. Weingart who expands on various aspects of DSI.
In addition to reviewing Dr. Weingart’s Delayed Sequence Intubation (DSI) [Episode 137] [See also Delayed Sequence Intubation (DSI) or Rapid Sequence Intubation (RSI)–An Outstanding EMCrit Podcast From Dr. Scott Weingart – In that post I made Summary Notes of Dr. Weingart’s Podcast 137 for my own quick review.]
In Podcast 23, Dr. LeCong interviews Dr. Weingart who expands on various aspects of DSI that he covered in EMCrit Podcast 137.
From 31:20 32:10 Dr. Weingart discusses Rapid Sequence Airway and why Delayed Sequence Intubation might be better (safer) in some circumstances than Rapid Sequence Airway.
[In rapid sequence airway you push your ketamine (or whatever) and your paralytic simultaneously and then place an LMA or other supraglottic device. So there is a bit of an unknown-Dr. Weingart is very comfortable using an LMA. But if you have any problem placing the LMA then you have converted a breathing patient that you have time to oxygenate and denitrogenate into a crash intubation. If you go with Delayed Sequence Intubation and you are forced to use an LMA or ET tube by circumstances as opposed to having to bag patient, at least you aren’t the reason it becomes a crash situation.]
From 32:10 to 36:20 Dr. LeCong and Dr. Weingart discuss awake intubation as an alternative to DSI. Dr. LeCong asks Dr. Weingart “what about an awake intubation with some ketamine sedation and a bit of topical sedation? Wouldn’t that be safer than DSI?” Dr. Weingart says that awake intubation and delayed sequence intubation are for two different groups of patients. Awake intubation is for patients who the doctor suspects are going to be anatomically very difficult to intubate. Those are the only patients I would do an awake intubation on because it is technically difficult and easy to cause airway trauma and it is hard on the patient. If I don’t anticipate a difficult airway, I would go with delayed sequence intubation.
And from 36:30 to 42:00, Drs. LeCong and Weingart discuss the occasional patient in whom you plan your DSI for safe denitrogenation and preoxygenation and the patient gets better on his brief period of CPAP or Bi-Pap and now you think the patient doesn’t need to be intubated. Well, that is a clinical judgement. But never (at least at this time – because there isn’t really enough experience) give ketamine and CPAP or Bi-Pap to temporize to avoid intubation. And you always when performing DSI need all the airway equipment right by the patient ready to go. And once you have pushed the ketamine you must stay with the patient because the patient can aspirate [the noninvasive positive pressure can push the vomitus down the airway] and if no one is continuously watching the patient, disaster can occur. Dr. LeCong summarizes: “The takeaway concept is that DSI is for intubation. . . . You will come across cases where people do improve dramatically and then you have to make your own clinical judgement whether proceeding with your plan to secure the airway and ventilate them is still the right one. Or whether a period of observation is [now] indicated. But we need to be careful of giving people the idea” that this [delayed sequence intubation] can be used for a trial of non-invasive ventilation. And Dr. Weingart emphasizes that patients who are not intubated for whatever reason who are on CPAP or Bi-Pap need to be watched much more closely then those patients who have been intubated and ventilated.
And from 44:30 to 46:40 Dr. Weingart says: “I’ll take it one step further. What Rob is suggesting is that perhaps every sick patient – if they are sick enough to need DSI – you might as well just go ahead and put them on CPAP preoxygenation and I agree with that point. Because when you look at [not sure of the name] reworking of the original anesthesia data, sick patients have a dramatically shorter time until they desaturate. Why is that? Well, it is because sick patients don’t have as much functional residual capacity as non-sick patients. And if you look at the article that Levitan and I wrote for the Annals of Emergency Medicine, anesthesia is the ones who have already been pushing CPAP preoxygenation for patients they feel have a decreased FRC – for those patients who are obese or critically ill. And it very well be that, in the future, that none of our patients are getting non-rebreather preoxygenation – whether they are getting DSI or they are perfectly tolerating this [the non-rebreather mask] – they’ll all be getting CPAP preoxygenation because I believe in my heart that it can’t hurt. And it can definitely have a huge potential to help with a couple of provisos: And those provisos are: You have to be very careful about the pressures you are using. I don’t recommend Bi-Pap for almost any case because Bi-Pap is going to be additive to your CPAP and CPAP is what is going to increase the FRC and gives you the best chance of preoxygenation. And then I would never put my CPAP above 15. If the patient needs more than a CPAP of 15, then you just accept what you have and proceed to Rapid Sequence Intubation if you can’t get them any higher after a few minutes. [And that is] because there is a level at which the esophageal sphincter will open and you will entrain air. In most patients that is around 22 to 23 cm of water. And I tell everyone that ED patients are different and you can’t extrapolate necessarily from the anesthesia literature which is where that came from so I want to set our bar even lower. So I say never go above 15 total pressure in the ED on your noninvasive on your nonintubated patient (and they’re always nonintubated [since that is why you are performing DSI] because I don’t want to risk opening that lower esophageal sphincter and risk gastric entrainment of air.
At 48:00 to Dr. Weingart summarizes: “If I had to leave one take home point, we spend a lot of time in emergency medicine talking about predicting the difficult airway [LEMON, MOANS, etc]. I think we should be looking at difficult physiology as well before every intubation. And the three for me, the three I teach about are hypotension, oxygenation, and ventilation issues. And you should be asking yourself: Does the patient have any of those issues before any intubation [See Dr. Weingart’s posts: Podcast 3 – Laryngoscope as a Murder Weapon (LAMW) Series – Ventilatory Kills – Intubating the patient with Severe Metabolic Acidosis May 22, 2009; Podcast 104 – Laryngoscope as a Murder Weapon (LAMW) Series – Hemodynamic Kills August 5, 2013; Hypoxia – See Preoxygenation, Reoxygenation and Deoxygenation].” If the patient has any of the HOP killers as Dr. Weingart calls them, then maybe you should consider delayed sequence intubation.