Showing posts with label endotracheal intubation. Show all posts
Showing posts with label endotracheal intubation. Show all posts

Thursday, April 11, 2013

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.
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. 
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.
6.  Use a combined VL/DL device if you have one available.  
  • Allows attending to visualize structures to augment safety and correct the learner. 
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.
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        Tuesday, July 17, 2012

        Direct Laryngoscopy May Be Dead - Just Not to Me

        The Gist:  Video laryngoscopy (VL) augments patient safety and is a great tool for endotracheal intubation (ETI) but trainees should likely be comfortable with both DL and VL.  There's a solid argument for Emergency Physicians to maintain DL skills while using the capabilities proffered by VL in situations to improve training and patient safety.  (As a medical student, I recognize I have minimal experience and probably should not have an opinion on this issue but, like most things, I do).  For expert airway tips and tricks, visit Life in the Fast Lane's Own the Airway.

        A couple of months back, I heard something frightening in the midst of shoulder presses at the gym - that direct laryngoscopy is dying.  On the superb Prehospital and Retrieval Medicine (PHARM) podcast, interviewee Dr. DuCanto discussed the importance of fiberoptic laryngoscopy during difficult airways.  Days later, I shuddered again, when I found that Dr. Ron Walls proclaimed DL "dead" via Twitter.  This discussion struck entirely too close to home.  

        In preparation for intubation, many attendings, upon seeing my eager, young face, steer the Glidescope in my direction.  I discovered a little bit of confidence is a dangerous thing when the airway is involved; thus, I love having this tool powered up and ready.  It's perfect for airways during chest compressions/resuscitation and many difficult airways.  Like the faithful bougie, I like to have a fiberoptic device at the bedside during an ETI.  However, it seems that many physicians think one should learn to intubate solely with video laryngoscopy but in my limited experience, I have run into occasional problems where I converted from VL to DL with immediate success.  Of note, however, I wasn't taught any specific set of skills for VL.

         Video laryngoscopy is superb in many ways.
        • It allows more than one person to visualize the airway well.  
          • This is especially valuable in training situations, allowing the trainer to give real time feedback to the trainee.  Additionally, this adds some theoretical patient protection (Although, in the age of apneic oxygenation, it probably routinely adds more trainee protection, "No, sir, that would be the gooose, try again.")  
          • Safer for some difficult airways. Again, VL allows more than one individual the opportunity to visualize the airway which, in my experience (dangerous words!),  can be helpful for team problem solving.   
        • Airway outsourcing (see EMCrit Wee:  I've always wanted a henchman/woman).  I think that most good Emergency Physicians have at least a third, if not fourth, hand tucked away somewhere.  Either that or they've mastered the art of preparation and adaptation for various procedures.  The following tasks can be outsourced, allowing the operator to keep their hands free/clutching the tube/bougie.   
          • I have a clear disdain for cricoid pressure as it has destroyed more views of the cords than it's created for me; however, laryngeal manipulation using the VL is an excellent idea, if needed.
          • Suction. Again, an assistant can direct the Yankauer to the necessary regions without getting in the way (too much, theoretically).  
          • Prepass bougie/ETT.
        • A combination VL/DL exists in the C-Mac device, which allows an intubator to use a VL view or DL view.  While I have no first hand experience with this device, studies such as this one in Anesthesia & Analgesia, look promising.  This study in BMC Anesthesiology demonstrates that the VL view resulted in faster visualization but actually required a greater number of attempts at ETI for success (perhaps due to operator familiarity/lack of training). 
        So, why am I somewhat reticent?
        • Different skill set than DL, at least to do VL correctly.  Drs. Weingart and DuCanto on EMCrit Episode 73 highlight some necessary differences to properly perform VL. 
          • The individual performing ETI should focus their gaze as such:  Mouth -> Screen -> Mouth -> Screen. 
          • Hold the ETT further back and rotate 15 degrees, using a rotatory motion of the thumb and forefinger
        • Sometimes the VL screen gets obscured by blood, secretions, or fog.  Most airways in EM are less pristine than the ones I initially trained on in the OR.  In these cases, DL may allow for quicker ETI.  
        • Passing the tube is somteimes more difficult with the Glidescope as there seems to be less space in the mouth.  Sometimes good technique can overcome this, but some studies demonstrate the ETI time isn't consistently lower in the VL group (the time to good view may be quicker, but not to cord placement).  The literature pretty consistently shows that one can achieve a technically good view in less time with VL but the time to ETI is not consistently better across studies (1,2).  
          • For example, this trial showed an average time to ETI of 22.5 sec (18-29.5) with DL compared with 33 sec (27.5-35.5) with VL (Glidescope), which was statistically significant.  This may be in part due to operator familiarity, favoring DL, but I think this point is still valid.
          • A meta-analysis in the Canadian Journal of Anesthesia demonstrated a statistically significant difference, favoring VL, in achieving a good view of the cords; however, there was no statistically significant difference in time to ETI between DL and VL. 
        • VL is a technology/electricity dependent process.   I grew up in an area of the US where natural disasters may leave a community without electricity for a month and leave buildings/one's house in ruins.  I've spent a fair amount of time in South Asia where these situations are more like a way of life.  Many areas of the world are resource limited and may have frequent power outages and limited funds for this equipment.  

        (Cox's Bazaar, Bangladesh, 2010)

        Take home?
        Best said by Dr. Seth Trueger @MDaware on Twitter:  "VL/DL = belt + suspenders. and real time training. and supervisor midaz"  

        References:


      • (1)NIFOROPOULOU P,
      • PANTAZOPOULOS
      • I, 
      • DEMESTIHA
      • T, 
      • KOUDOUNA
      •  E, 
      • XANTHOS T. 
        •  Video-laryngoscopes in the adult airway management: a topical review of the literature Acta Anaesthesiologica Scandinavica Volume 54, Issue 9, pages 1050–1061, October 2010 


      • Groeben H.
        • Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients.  Br. J. Anaesth.102 (4):546-550

        Note:  I use Glidescope interchangeably with VL at times when talking about personal experience since it's the VL method I have the most experience with.  
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