The past year gave us some impressive research that every emergency physician should review to stay on top of the latest trends and techniques in airways, from using delayed sequence intubation and predicting difficult intubations to apneic oxygenation and extraglottic airway devices. These 12 articles are must-reads.
Delayed Sequence Intubation: A Prospective Observational Study
Weingart SD, Trueger NS, et al.
Ann Emerg Med
Adequate oxygenation in patients with refractory hypoxemia and altered mental status is a challenge. One alternative to standard RSI is delayed sequence intubation (DSI), which is “essentially procedural sedation with the procedure being preoxygenation.” The sample size was small, but this study found DSI to be effective and safe, and that is consistent with our own clinical experience with this technique.
Prospective Validation of the Modified LEMON Criteria to Predict Difficult Intubation in the ED
Hagiwara Y, Watase H, et al.
Am J Emerg Med
These authors from Japan removed the Mallampati score from the commonly used LEMON mnemonic to predict difficult intubation (Look externally, Evaluate the 3-3-2 rule, Mallampati, Obstruction, Neck mobility). The modified LEMON, or LEON, was 95% sensitive for predicting difficulty with video laryngoscopy and 85% with direct laryngoscopy. The negative predictive value — the score is correct in saying you will not have trouble — was 98 to 99% for video and direct laryngoscopy. We can rarely evaluate a true Mallampati in the ED population, so it is good to know the mnemonic still has utility at predicting anatomic airway difficulty. Moving forward, you will hear more discussion about physiologic airway difficulty. Years ago, we added an “S” for saturation because oxygenation equates with available time and therefore difficulty. (Ann Emerg Med 2006;47:581.)
Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill
Semler MW, Janz JR, et al.
Am J Respir Crit Care Med
2015 Oct 1. [Epub ahead of print]
Apneic Oxygenation was Associated with Decreased Desaturation Rates during Rapid Sequence Intubation by an Australian Helicopter Emergency Medicine Service
Wimalasena Y, Burns B, et al.
Ann Emerg Med
Use of High-Flow Nasal Cannula Oxygen Therapy to Prevent Desaturation during Tracheal Intubation of Intensive Care Patients with Mild-to-Moderate Hypoxemia
Miguel-Montanes R, Hajage D, et al.
Crit Care Med
Apneic nasal oxygenation has become standard in our emergency department. This year saw three publications on this topic: two in the ICU and one prehospital. Because nothing in medicine can be simple, two of these studies (Wimalasena and Miguel-Montanes) demonstrated significant benefit and one did not, though no harm was found. Until ED-based studies come out, we believe the weight of evidence supports this simple adjunctive technique.
Out-of-Hospital Pediatric Airway Management in the United States
Hansen M, Lambert W, et al.
Out-of-hospital pediatric endotracheal intubation occurs rarely in children. Hansen, et al. analyzed a large national EMS data set and found that the overall prehospital intubation success rate for cardiac arrest was 75 percent with presumably much lower rates on the critical first attempt. Unfortunately, extraglottic devices were used in less than 400 cases. The weight of the evidence favors bag-mask ventilation and probably extraglottic devices over intubation for pediatric cardiac arrest. New Mexico has removed pediatric intubation from the EMS scope of practice following the lead of Los Angeles and Orange counties.
Factors Associated with Oxyhemoglobin Desaturation during Rapid Sequence Intubation in a Pediatric Emergency Department: Findings from Multivariable Analyses of Video Review Data
Rinderknecht AS, Mittiga MR, et al.
Acad Emerg Med
This research conducted by analyzing video-recorded data shows the duration of laryngoscopy insertion is associated with desaturation, not the number of attempts. The authors used video review as a primary method of data collection, and evaluated 114 pediatric patients undergoing RSI. The duration of individual intubation attempts longer than 30 seconds was strongly associated with desaturation (odds ratio 5.7). The take-home message here is that the total duration of laryngoscopy matters.
Radiographic Evaluation of Carotid Artery Compression in Patients with Extraglottic Airway Devices in Place
White JM, Braude DA, et al.
Acad Emerg Med
This small case series from our institution did not demonstrate CT evidence for mechanical compression of the carotid arteries by inflated extraglottic airway devices. This counters concerns raised by a previous swine study, and suggests human anatomy is not the same as pigs, though our patients were all well perfused and not in cardiac arrest. It is perhaps most interesting that we frequently send ED patients to the CT scanner with well-functioning extraglottic devices in place.
Techniques, Success, and Adverse Events of Emergency Department Adult Intubations
Brown CA 3rd, Bair AE, et al.
Ann Emerg Med
This is an analysis of data from 13 sites participating in the National Emergency Airway Registry. Most of the attention has focused on the remarkable rise of video laryngoscopy (now used in 27% of first attempts), but I was more interested to see that rocuronium is now used in 42 percent of cases. We switched to nearly exclusive use of rocuronium more than 10 years ago, and people used to say we were crazy. We may be, but now we have lots of crazy company.
Postintubation Hypotension in Intensive Care Unit Patients: A Multicenter Cohort Study
Green RS, Turgeon AF, et al.
J Crit Care
2015 Jun 16. [Epub ahead of print]
This retrospective study found a 46 percent incidence of post-intubation hypotension in the ICU, which was associated with increased mortality. We are strong advocates for “resuscitate before you intubate” whenever possible and being aggressive with fluids and pressors in the peri-intubation period. Back to the concept of the physiologic difficult airway.
Incidence and Duration of Continuously Measured Oxygen Desaturation during Emergency Department Intubation
Bodily JB, Webb JR, et al.
Ann Emerg Med
2015 Jul 9. [Epub ahead of print]
This is another paper from our own institution demonstrating that one in three patients desaturate during ED intubation when you look closely for it. We found that a pre-intubation SpO2 below 93 percent, multiple attempts, and prolonged intubation time were all predictive of desaturation. These data were collected prior to the routine use of apneic oxygenation and DSI, so hopefully the data will look better now. Pay close attention to patients whose saturation is below 93 percent after pre-oxygenation when you apply the LEMONS or LEONS mnemonic.
The C-MAC Video Laryngoscope is Superior to the Direct Laryngoscope for the Rescue of Failed First-Attempt Intubations in the Emergency Department
Sakles JC, Moslier JM, et al.
J Emerg Med
2015 Dec 11. [Epub ahead of print]
The first attempt should be the best attempt, but what if it fails? Sakles, et al. compared C-MAC and direct laryngoscopy for rescue. The C-MAC was successful in 82 percent of cases when used for the second attempt. The DL, however, was successful in only 62 percent of cases, regardless of the initial device used. The adjusted odds ratio for successful rescue intubation on the second attempt by using C-MAC compared with the DL was 3.5. You should have a video device available and be comfortable using it for subsequent attempts even if you elect not to use it for your first try.