Indulging in Intubation - Lessons for the Novice

The Gist:  Learning endotracheal intubation (ETI) is both a privilege and a risky endeavor.  As patient safety is of the utmost importance, some situations may not be appropriate for novice intubators.  Dr. Minh Le Cong posed a question regarding who should intubate, discussed here, and Dr. David Marcus also has posts on this topic here and here. There are some things, however, that a novice intubator can do to maximize their learning process in an efficient and safe manner.

• Note:  I'm not an expert and this is not an evidence-based review.  This is essentially a "Tricks of the Trade" post.

Last year, I wrote this post after an anesthesia rotation.  I'm finishing up a final airway elective, both in preparation for residency and as a gift to myself after a month of public health research. I realized I had benefited from many things gleaned from Free Open Access Medical education (FOAM) world.  Here are some things that have made an impressive difference..

My Top 10 List

1.  Know what you're getting into.   Dr. Minh Le Cong has built a #FOAMed airway curriculum.

• Dr. Levitan video 
• Life in the Fast Lane's site 

2.  Do an anesthesia rotation.

• Allows for controlled, planned control of the airway.  This is part of the PGY-1 curriculum in U.S. EM programs, but it's also helpful as a medical student where one can easily get 40-50+ intubations in a month.  
• Allows one to see what happens after the tube is secured such as response to pain, duration of medications, ventilator management.  
• On a non-airway note: excellent for nerve blocks and arterial lines as well.

3.  Verbalize what you see see and do every step of the way during ETI.

• An attending once told me, "It feels like an eternity when you're not holding the laryngoscope." Attendings get nervous if they can't see what's going on.  Let everyone know when you're "in the vallecula" if you're using a Macintosh blade, when you see cords/arytenoids, or if something (like cricoid) isn't working. 

@lwestafer and even if you can't see anything: "I'm moving down e tongue... Moving down... staying midline" = supervisor ativan
— Seth Trueger (@MDaware) April 4, 2013

@embasic @mdaware @lwestafer Agreed but having a learner talk thru it really makes them think and realize what they know vs what they don't!
— Corey Heitz (@CHeitzMD) April 4, 2013

4.  Know the physiologic responses to induction drugs and laryngoscopy.  Control of an airway isn't just about placing the tube - induction drugs, laryngoscopy, and the patient's underlying medical status do bizarre things to hemodynamics.  When it becomes available, check out the lecture given on the opening day of the Social Media and Critical Care Conference by Dr. Scott Weingart.

• Post-intubation hypotension (PIH)
• Heffner et al: 1 year retrospective cohort (~1/2 eligible were excluded) showed that PIH is common (22%, n=66) and associated with respiratory processes and a shock index (HR/SBP) >0.8 prior to ETI.  The percentage is essentially the same as their prior study (23% with PIH; nearly all intubated with etomidate, often referred to as "hemodynamically stable").
• Another, more heterogeneous study by Green et al, didn't show any clear associations between PIH and medications but demonstrated that patients with underlying respiratory issues are more likely to have PIH and sustained PIH is associated with badness on the mortality front.
• In the OR, the induction propofol and fentanyl were always backed by sticks of phenylephrine "just in case."  A recent EMRAP episode (subscription required) featured a debate on this concept between Drs. Amal Mattu and Scott Weingart.

• Laryngoscopy causes stimulation of the sympathetic and parasympathetic innervation to the hypopharynx, larynx, and trachea.
• Increased heart rate (~30 bpm) and blood pressure (~25mmHg) thought to be due to release of catecholamines secondary to CN IX,X stimulation and renin-angiotensin aldosterone system (1).  
• Bronchoconstriction due to parasympathetic stimulation (1).
• Note: Pediatric patients may have bradycardia, pretreatment with atropine in some infants is of controversial utility (1).

5.  Use airway adjuncts.

• Video laryngoscopy (VL) devices often require a different skill set in passing the tube through the cords. Some institutions have one start with VL before direct laryngoscopy (DL) but in others, this is not routine practice, so get some experience.
• Mask ventilation.  Practice the two-handed technique, not the inferior E-C taught in BLS (Hart et al).
• Get a feel for the bougie - it can be surprisingly difficult to induce memory.

@lwestafer practice using bougie in elec settings, and use it in Gr 2 as well to maximize first pass success.
— Taylor (@canibagthat) April 4, 2013

@lwestafer Agree!At least 5-10 elective intubation w/bougie, and keep the laryngoscope in place untill tube passed the cords! @canibagthat
— Lars Aune Svarthaug (@svarthaug) April 4, 2013

6.  Use a combined VL/DL device if you have one available.  

• Allows attending to visualize structures to augment safety and correct the learner. 

@mdaware @lwestafer or just use a C-MAC = supervisor nirvana
— Steve Carroll, DO (@embasic) April 4, 2013

7.  Know your limits. First-pass success in ETI is important, keep this and the patient in mind.  Opportunities may arise when a difficult airway is placed in your hands.  Know when to say no or ask for help.

• A recent retrospective analysis of ED intubations in Academic Emergency Medicine by Sakles et al demonstrated adverse events (AE) increase with a greater number of ETI attempts.
• 1st pass success = 14.2% with AE (n=1333; 72.9%)
• Multiple ETI attempts = 53.1% with AE
• Note: AEs included esophageal intubation, oxygen desaturation >10% (most common), hypotension, dysrhythmia, laryngospasm, etc.  Some of these are probably more clinically important than others.
• A multi-center prospective study of n=2616 in Japan by Hasegawa et al demonstrated an adjusted odds ratio of 4.5 (95% CI 3.4 to 6.1) for AE in multiple attempt ETIs.

8.  Establish an airway plan.  Seemingly easy, straight-forward airways can become surprisingly difficult.  As an attending told me, "the purpose of procedures in Emergency Medicine is to keep you humble."  Stay curious and never assume you've "got it in the bag." The scariest ETIs I've been a part of were unanticipatedly difficult, perhaps, in part, due to lack of preparation.

• Talk through your plan with the attending/team to ensure you have an appropriate plan, communicate the plan, identify any pitfalls, ensure proper materials, and demonstrate knowledge. 
• In the ED, even if you plan to do DL, bring the VL device to the bedside.  If DL fails, the back up plan is ready. 
• Identify and plan for patient co-morbidities such as pulmonary disease, obesity (see video by Dr. Winters, EDexam post, GI bleed, increased intracranial pressure, or trauma.  

9.  Remember that ETI doesn't end with the passing of the tube.  

• Ensure your patients have sufficient analgesia on board.
• Ensure ventilator settings are appropriate to the situation.  For example, some patient populations need longer expiratory times (asthmatics) or higher respiratory rates (DKA, salicylate ingestion, need for CO2 regulation).
• This EMCrit post has some neat checklists at the bottom to help one systematize post-intubation care.

10. Avoid hypoxia.

• Use apneic oxygenation (NODESAT).  If the attendings don't use this, it offers an opportunity for discussion (at an appropriate time, away from the patient's bedside).  
• Recognize pulse oximeter lag and the limitations of the pulse oximeter, as demonstrated by Dr. Rob Bryant.  

Note:  some attendings may interpret some of these points as a "sign of weakness," so be prepared and do what's best for the patient.

References:

1.  Ron Walls and Michael Murphy.  Emergency Airway Management. 3rd edition. 2008: Philadelphia, p222-229.

A Web Curriculum for Learning Endotracheal Intubation

The Gist:  The airway is one of the fundamentals of emergency medicine.  It's imperative to be familiar with terminology and procedures associated with the airway.  Fortunately, there is a cornucopia of excellent information to make this easier for a beginner navigating endotracheal intubation and the airway in general. Below is a basic outline of the initial approach to learning endotracheal intubation, courtesy of the dedicated podcasters and bloggers.

Why is the airway important?  Without one, you don't have a patient.  Or, rather, you don't have an alive patient.  Furthermore, these procedures are fun, humbling, make an enormous difference on patient outcomes, and there's a unique exhilaration in the improvisation and collaboration that accompanies a difficult airway (like this one).  Also, with the amazing advent of video laryngoscopy, many attendings encourage utilization of these devices for the novice intubater.  These devices are great, but I think that solid comfort with direct laryngoscopy is important.  Best bet?  Arrange to do an anesthesia rotation during clerkships!

I had an incredible experience on my anesthesia rotation and realized that part of the experience was derived from the didactics I inadvertently received by following various podcasts and blogs.  I was so impressed with the information put out there by Emergency Medicine physicians that I felt others could benefit from this information and intervene on their first airway with confidence, skill, and knowledge.  Sure, much of the basic endotracheal intubation skill revolves around the sheer number performed but the experience is much more pleasant, beneficial, and interesting with a basic understanding.

Do you want to own the airway?  Everything one needs is here, courtesy of the fine folks at Life in the Fast Lane, the ultimate source for Emergency Medicine education on the web.  By far, the most comprehensive "all in one" reference.

EMBasic Airway Episode by Dr. Steve Carroll- I recommend subscribing to the podcast through iTunes. 

• Airways exist on a spectrum of difficulty and one may be fooled into a false sense of security in the initial assessment of the airway.  Expect an airway to be difficult unless proven otherwise.  Dr. Carroll does a great job emphasizing this point.

• Note, this podcast talks some about drugs used in Rapid Sequence Induction (RSI) and vaguely about rocuronium (a drug I prefer over succinylcholine), and this conversation, while part of the airway dialogue/process, shall be addressed separately..it would just be too cumbersome here.

EMCrit's Podcast 70 - Airway Management with Rich Levitan - This lecture is incredible.

• In fact, the podcast came out roughly halfway through my anesthesia rotation.  I had been doing some things precisely wrong!  My intubations were significantly better after the explicit and methodical approach to epiglottoscopy and laryngoscopy.  Again, I recommend downloading the video via iTunes

EmCrit Procedure Video here - awesome, succinct...well done.

Explore the AirwayCam website for photographs and a plethora of information on instruments, techniques, and more.  This site is absolutely incredible.  For example, there's an entire section on the amazing bougie!

Pre-oxygenation!  This paper by Dr. Scott Weingart and Dr. Richard Levitan is essentially a cheat sheet to preventing the O2 saturation monitor from beeping (thereby inducing tachycardia in the amateur intubater) during intubation.  More importantly, I think this is beneficial for patients. 

• ERCast video here.  Amazing!

This site by Dr. Minh Le Cong also has much to offer in airway education, although it's more advanced.

A Few Other Miscellaneous Pearls:
The ability to ventilate is paramount.  Check out EMCrit's Podcast Video 65 here (or download via iTunes)

• Unfortunately, we learned how to bag a patient incorrectly in ACLS.  Lose the "E-C" technique and utilize the two handed technique described in the above video. 

This site discusses different techniques to predict difficult airways.
The mnemonic OBESE may predict those that will be difficult to mask ventilate.  The presence of two of the following indicators predict difficulty (with sensitivity and specificity around 70%).

• Obese (BMI >26), Bearded, Elderly (>55 y/o), Snorers, Edentolous (No teeth) 

The LEMON score isn't near perfect but it can aid in the assessment of the airway.  The score has a maximum of 10 points with one point for each of the following. Higher score = increased difficulty. 

• L=Look externally (facial trauma, large incisors, beard or moustache, and large tongue)
• E=Evaluate the 3-3-2 rule (incisor distance <3 fingerbreadths, hyoid/mental distance <3 fingerbreadths, thyroid-to-mouth distance <2 fingerbreadths) - perhaps the most predictive
• M=Mallampati (Mallampati score of 3 or greater)
• O=Obstruction (presence of any condition that could cause an obstructed airway)
• N=Neck mobility (limited neck mobility).

Much much more to come on this issue.  In the future....drugs and scary, humbling, proactive and fun airways

Successful ETI is not solely passing a tube through the cords.  After intubation, there's still much to do.  Check out EMCrit's post-intubation package podcast.

References:
Thanks to all of the incredible physicians and educators who create and disseminate this information.