It's time again to review the most interesting contributions to the emergency airway literature from the past year, one that delivered quite a few interesting articles to help emergency physicians feel more comfortable with airway techniques.
Manual In-Line Cervical Spine Stabilization
* Santoni BG, et al. Manual In-Line Stabilization Increases Pressures Applied by the Laryngoscope Blade During Direct Laryngoscopy and Orotracheal Intubation. Anesthesiology 2009;110(1):24.
* Thiboutot F, et al. Effect of Manual In-Line Stabilization of the Cervical Spine in Adults on the Rate of Difficult Orotracheal Intubation by Direct Laryngoscopy: A Randomized Controlled Trial. Can J Anesth 2009;56(6):412.
* Turner CR, et al. Motion of a Cadaver Model of Cervical Injury During Endotracheal Intubation with a Bullard Laryngoscope or a Macintosh Blade with and without In-Line Stabilization. J Trauma 2009;67(1):61.
* Bathory I, et al. Evaluation of the Glidescope for Tracheal Intubation in Patients with Cervical Spine Immobilization by a Semi-Rigid Collar. Anaesthesia 2009;64(12):1337.
All these articles are more evidence that patients in cervical precautions present difficult airways: Manual in-line stabilization (MILS) of the cervical spine significantly impairs direct laryngoscopy (DL) without necessarily protecting against cervical movement. Video laryngoscopy can overcome these issues, achieving successful intubation without removing the cervical collar or tape.
Mort TC, et al. Extending the Preoxygenation Period from 4 to 8 Mins in Critically Ill Patients Undergoing Emergency Intubation. Crit Care Med 2009;37(1):68.
Preoxygenation is critical to safe RSI. In my August 2006 column, I called for at least three minutes with a non-rebreather and suggested consideration of CPAP/BiPAP. (EMN 2006;28:8; http://bitly.com/Preoxygenation.) More is not necessarily better: Four minutes is not only sufficient, but some critically ill patients will actually deteriorate with the added delay.
Kheterpal S, et al. Prediction and Outcomes of Impossible Mask Ventilation: A Review of 50,000 Anesthetics. Anesthesiology 2009;110(4):891.
Impossible bag-mask-valve ventilation is very rare, but it is even scarier than difficult intubation. Neck radiation changes, being male, sleep apnea, Mallampati III or IV, and a beard are independent predictors of impossible BVMV. Because many of these also predict difficult intubation, beware!
Lighting the Way
* Rhee KY, et al. A Comparison of Lighted Stylet (Surch-Lite) and Direct Laryngoscopic Intubation in Patients with High Mallampati Scores. Anesth Analg 2009;108(4):1215.
With all the focus on video laryngoscopy to replace DL, cheaper technology such as intubating laryngeal masks and lighted stylets (LS) should not be overlooked. In this study, a simple LS was superior to DL in patients with potentially difficult airways. Consider adding some type of LS to your airway cart; I am personally more comfortable with a Trachlight or Trachlite.
Which Bougie is Best?
* Janakiraman C, et al. Evaluation of Tracheal Tube Introducers in Simulated Difficult Intubation. Anaesthesia 2009;64(3):309.
* Braude D, et al. Comparison of Available Gum-Elastic Bougies. Am J Emerg Med 2009;27(3):266.
My colleagues and I compared four products, and found the SunMed was preferred overall. Janakiraman et al found the Frova single-use and Eschmann multiple-use introducer to be most successful. With more and more introducers being marketed, it is worth noting that they are not all created equal. Caveat emptor.
Etomidate, Ketamine, and the Grim Reaper
* Tekwani KL, et al. A Prospective Observational Study of the Effect of Etomidate on Septic Patient Mortality and Length of Stay. Acad Emerg Med 2009;16(1):11.
* Jabre P, et al. Etomidate Versus Ketamine for Rapid Sequence Intubation in Acutely Ill Patients: A Multicentre Randomised Controlled Trial. Lancet 2009;374(9686):293.
* Bar-Joseph G, et al. Effectiveness of Ketamine in Decreasing Intracranial Pressure in Children with Intracranial Hypertension. J Neurosurg Pediatr 2009;4(1):40.
* Morris C, et al. Anaesthesia in Haemodynamically Compromised Emergency Patients: Does Ketamine Represent the Best Choice of Induction Agent? Anaesthesia 2009;64(5):532.
Myths of etomidate killing septic patients and ketamine killing head injury patients have been debunked (in fact, ketamine was protective!), but in a head-to-head comparison, it was a disappointing tie. I still believe etomidate is the single best agent for all comers, but ketamine is safe.
* Rice MJ, et al. Cricoid Pressure Results in Compression of the Postcricoid Hypopharynx: The Esophageal Position is Irrelevant. Anesth Analg 2009;109(5):1546.
We can put a man on the moon, but the debate rages on whether cricoid pressure even compresses the esophagus. This MRI study shows that compression does indeed occur, but any protective effect on aspiration remains controversial. It remains more important to know when not to perform cricoid pressure: whenever visualization is difficult during DL. (See my column from October 2006: EMN 2006;28:24; http://bit.ly/Cricoid.)
▪ Hodzovic I, et al. Fibreoptic Intubation through the Laryngeal Mask Airway: Effect of Operator Experience. Anaesthesia 2009;64(10):1066.
Flexible fiberoptic intubation requires tons of experience unless you perform it through an LMA. In this study, operator experience did not affect success when performed through an LMA. When the scope comes out the end of an LMA, it is pointing straight at the glottis. This is a great technique for difficult airways, and deserves a role in the ED airway armamentarium.
* ▪Dhara SS. Retrograde Tracheal Intubation. Anaesthesia 2009;64(10):1094.
This is a very comprehensive review of a rarely used airway technique. I have never done one, but I feel better prepared now.
Roc vs. Sux
* ▪ Mallon WK, et al. Rocuronium vs. Succinylcholine in the Emergency Department: A Critical Appraisal. J Emerg Med 2009;37(2):183.
I feel compelled to include this one just to disagree with the esteemed authors. I am still a committed rocuronium guy.