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Newsletter January 2022: Second thoughts regarding rapid sequence intubation

Chief Editor note: This clinical paper raises an important dilemma for the practitioner. We expect comments and opinions from our readers.

Marcelo Ramos, MD
marcelosperiandoramos@yahoo.com

The most important decision in anaesthesia is whether to intubate BEFORE or AFTER induction. The basis of all the algorithms (and our beliefs) is that once we have defined that we can with “certainty and security” guarantee the ventilation (and/or maybe intubation), we can induce.

We propose and believe that whenever there is uncertainty or doubt about the ability to VENTILATE, the most prudent approach is to proceed with topical anaesthesia (with or exceptionally without) plus sedation (or exceptionally without) and perform the so-called “awake intubation” (ATI).

The recommended management of patients in whom a difficult airway is predicted is to perform “awake” intubation (ATI), which is accomplished using either a flexible intubation scope or (more recently), a video laryngoscope. In rougher environments, even the old-fashioned direct laryngoscope may do the trick, but with a much higher discomfort for the patient.

All this is based on a fictional presumption that we have the slightest idea how to identify which one among all the patients is difficult to ventilate or intubate.

Literature [1] [2] [3] [4] has repeatedly shown that the clinical evaluation of predictors for both difficult intubation and mask ventilation is NOT reliable, and yet we keep believing in our fictional ability to predict in which patient we are going to face difficulties. With all that said, I conclude that it is too preposterous of us to guide our conduct based on something that resembles “guessing”. How many of the predictors of difficult ventilation (or which ones in particular) do I need to decide whether to intubate someone before or after induction? For now, we do not know the answer to this question.

There are two different approaches to deal with the aspiration risk. The most common answer is to proceed with the so-called Rapid Sequence Intubation (RSI). The second choice is to intubate first and induce later (ATI – awake tracheal intubation).  The decision between RSI and ATI will be based on the perceived difficulty you could find in intubation. If you suspect that the intubation could be difficult you are compelled to choose ATI, for the sake of patient safety; if there is no reason to suspect that the intubation is difficult you are allowed to proceed with the so-called RSI. Up to this point in the text, there is no polemic question. The worst possible scenario is to have a difficult intubation patient apneic and unconscious, with a tangible aspiration risk with low and falling saturation. If you are uncomfortable with the fact that such an important decision is made based on a very fallible (unreliable) evaluation, it gets worse!

Traditional practice advocates that no mask ventilation should be performed in patients who are not fastened (aspiration risk), due to the presumed risk of gastric insufflation and facilitated regurgitation. Take into consideration that the rationale for RSI is that a paralysed patient with the head elevated to a level superior to the stomach is not able to either vomit or regurgitate, so this paralyzed patient is “safe” from the aspiration risk. Supposing that this rationale is true, this patient could be saved from the aspiration only to “safely die” from hypoxia in the case the anesthesiologist is not able to intubate. The key factor in the safety of RSI is fast success at the first attempt of intubation!

Let’s go to polemic number 1: If a patient’s life depends on the first attempt success, why try a method that is less reliable for first-pass success (direct laryngoscopy)? If the anaesthesiologist chose RSI there is an implicit commitment to achieve first-pass success. It should be obvious by now, after 20 years of the use of VL, that RSI should only be attempted with video laryngoscopy (VL)! So, optimising the first-pass success chance is mandatory every time RSI is chosen; it includes not only VL but VL with the head well above the stomach level (steep reverse Trendelenburg or at least 30-degree dorsum elevation). It also includes proper operator positioning; if the anaesthesiologist is not tall enough, he/she should perform the VL standing over a step to reach the proper operator positioning (head of the patient just below the xiphoid of the operator). I will deliberately NOT enter the polemic of “to do or not to do” cricoid pressure as an attempt to avoid regurgitation (this would make this text too long), but even if you disagree with me and still believe (not like me) in the Sellick’s manoeuvre and perform cricoid pressure, you certainly agree with me that VL certainly reduces attempts at intubation and enables monitoring of correct placement of cricoid force and its impact on the airway and facilitates adjusting manoeuvres (due to shared vision of the screen between operator and assistant). So, polemic question number 1: – Should we ban DL for good in the RSI scenario?

Keep the first polemic question in mind while I pose you the second (and for me more important) polemic question: Should we really avoid mask ventilation during the lapse of time in which the patient loses consciousness, and try the first intubation attempt? Or in other words, is the NO ventilation a reasonable rule?

I happened to read a recent study[5] that strengthened my belief that the NO ventilation rule is illogic, counterintuitive, a relic from the past, and should be banned. It confirms my practice of gentle mask ventilation during the interval between induction and laryngoscopy. Any oxygen is much better than NO Oxygen, that is why I always add (to gentle manual ventilation), the highest possible oxygen nasal flow while performing laryngoscopy (Levitan’s NODESAT[6] technique) whenever I take the option to perform RSI.

 

References

  1. [1] Nørskov, A. K., Rosenstock, C. V., Wetterslev, J. Anaesthesia, (2015), 70: 272
  2. [2] Lundstrøm LH, Rosenstock CV, Wetterslev J. Anaesthesia. 2019 Oct;74(10):1267
  3. [3] Roth D, et all. Cochrane Database of Systematic Reviews 2018, Issue 5.
  4. [4] Detsky ME, et all/ JAMA. 2019 Feb 5;321(5):493-503.
  5. [5] JD Casey. n engl j med 380;9 nejm.org February 28, 2019. 811
  6. [6]Scott D. Weingart, Richard M. Levitan, Annals of Emergency Medicine Volume 59,n3 March 2012 :165

6 replies

Alexandre Tarnopolsky
Dear Colleagues, interesting remarks, great discussions and experience changes. I want to focus some points. 1- In a VL era basically we only need a minimal mouth opening to suppose a high possibility to intubate and ventilate the patient in the absence of gross deformities, trauma and abscess of mouth/throat/neck region. As noted by Dr Marcelo Ramos, "clinical evaluation of predictors for both difficult intubation and mask ventilation is NOT reliable". 2- Fiberoptics image need a clear and clean area without excess o blood and secretions that may be not totally possible in face/oral trauma . That´s the reason we can´t abolish the classical laringoscope and DL as a technical option always tested and on the table.
5 months ago
Marcelo Sperandio Ramos
Dr. Jyoti Gupta The ONLY barrier to universal adoption of video laryngoscope as a default to intubation is the cost - I know no other feature that precludes the wide acceptance of video-assisted intubation. Nowadays, thanks to the popularization of 3D printing and automotive cameras, there are rudimentary VL that work reasonably well under US$ 50. These "homemade" VL are not as good as commercial brands, but they are far superior to any direct laryngoscope!
6 months ago
Marcelo Sperandio Ramos
Dear Dr. Jürgen Peters Answering your comment and questio0n: Are you suggesting that people move on attempting further intubations in the face of developing hypoxemia? The answer is NO, absolutely NOT! No patient has ever died for lack of intubation, all of them died for lack of Oxygen! If my intubation attempt (and I mean the best possible VIDEO laryngoscope attempt with the best possible positioning and after thorough pre (and PER) Oxygenation; I would immediately resort to a second-generation supraglottic device and ventilate gently, drain the stomach and try to use the supraglottic device as a conduit to flexible endoscopic intubation. Fixation in intubation attempts despite falling saturation is a common mistake to be avoided.
6 months ago
Christian Wunder
Dear Marcello, I totally agree with your opinion in performing RSI. Being consequent, RSI should only be attempted with video laryngoscopy (VL). And with reducing the pressure valve <20mmHg (in adults) there is no reason why gentle mask ventilation during the interval between induction and laryngoscopy should be dangerous. It's safe and reasonable! We do this technique in children as well.
7 months ago
Dr. Jyoti Gupta
Dr Ramos thanks for writing this interesting newsletter. This is a very important topic for anaesthesiologists world wide. Banning DL in the concerned scenario is a logical approach in present times but cannot be applied universally. It's always safer to go for awake intubation and as you said better in cases demanding RSI. I would always give oxygen by high flow nasal cannula during paralysed RSI avoiding manual ventilation, as you rightly said some oxygen is better than no oxygen. Thanks again for providing an interesting read.
7 months ago
Jürgen Peters
Dear Doctor Ramos: This short article reminds me of an old saying about pornography: "You can't define it but you (may) recognize it once you see it". Like the intubation paradigm you elaborated on it surely depends definitely not on measurements but rather on personal experience in assessment of the facial and neck configurations as well as on years of practice of intubation what will turn out a proper decision. What works with 20 years of experience and as a trouble shooter may not work with only 10 years, especially when it comes to double lumen tubes. Not to forget, lets face it, that residents need ample experience in awake fiberoptic intubation so they are not failing with insufficient practice when it comes to it. However, after all, what really is the problem? If you made a (post hoc) wrong decision for RSI and intubation fails you surely have to resort to mask ventilation and reconsider your choices left. Are you suggesting that people move on attempting further intubations in the face of developing hypoxemia? That would be a poor choice indeed and no anesthesiologist should do that. Thus, as almost always, it depends on good judgement so that it appears to me that a non-problem was outlined. Regards, Jürgen Peters, Prof. emeritus, Univ. Essen
7 months ago

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