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News: Don’t Throw Your Candle Away Yet: Emergency Medicine News

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candle, CANDLE test, BEAM test, intubation

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I consider myself a candle enthusiast and was eagerly awaiting the results of the first multicenter randomized controlled trial to confirm my success.

Much to my dismay, the CANDLE trial found no difference in first pass intubation success between the two groups – 80.4% for the candle versus 83% for the stylet (p=0.27). The study also showed no difference in the incidence of hypoxia or procedural complications.

Is it time to throw away the candle? Like most things in evidence-based medicine, the answer is complicated.

The BEAM trial

I have primarily used the candle throughout my short career in emergency medicine, and it has reliably produced great results in my overall intubation success. I advocated tirelessly for its use and turned a handful of my fellow residents into loyal sidekicks.

The BEAM (Bougie Use in Emergency Airway Management) trial had a profound impact on my approach to airway management. (JAMA. 2018;319[21]:2179; https://bityl.co/D2bD.) It showed 98% first-pass success when intubating with a candle, compared to 87% with a stylet. The results were impressive, but it was achieved in a single emergency department where candle use was the norm. Its results were ripe for confirmation by a larger multicenter study to strengthen its generalizability.

Enter the CANDLE trial. The Candle or Stylet in Patients Undergoing Intubation Emergently trial assessed the effect of candle on first-pass intubation success. (JAMA. 2021;326[24]:2488; https://bityl.co/D2bF.) It randomized 1102 patients in 15 emergency departments and ICUs from nine hospitals to undergo intubation with a candle or stylet-loaded endotracheal tube. Their median age was 58 years and 41% of patients were women. Sixty percent of intubations took place in the emergency room and 40% in intensive care.

In Defense of the Candle

This was a well-done study with valid results, but it begs the question why the BEAM trial produced such impressive results and the BOUGIE trial failed to replicate them.

The BEAM trial was conducted at the Hennepin County Medical Center, where residents are trained in the use of the candle for their first intubation pass. Fourteen of the 15 emergency and intensive care units in the BOUGIE trial, however, used a candle on the first attempt “sometimes” or “rarely” before the study. Additionally, the median number of attempts with a candle per proceduralist prior to the study was only 10. Such limited experience with the candle likely contributed to its lack of effectiveness in this study. You have to use it if you want the candle to work for you!

Another interesting limitation is found in the supplement to the article. Eleven of these 15 emergency and intensive care units formed a bend in the candle before intubation “sometimes” or “rarely”. I find it difficult to pass a straight candle through the vocal cords (imagine trying to pass an endotracheal tube with a straight stylet), and recommend forming a slight bend to allow it to follow the natural curvature of the oro- and hypopharyngeal structures.

The trial protocol encouraged the formation of a 25-35 degree bend in the stylet to facilitate intubation, which is considered standard practice. (BMJ open. 2021;11[5]:e047790; https://bityl.co/D2bL.) But he did not recommend forming a similar curvature with the candle—that was left to the physician performing the procedure—so the trial authors likely introduced a bias against the candle group.

Find the best approach

The stylet group in the BEAM trial had an 87% success rate compared to the low 80s for each group in the BOUGIE trial. This difference may be explained by the different definitions of a single attempt in each trial. The BEAM trial defined an attempt as each insertion of the laryngoscope blade, while the CANDLE trial defined an attempt as each insertion of the candle or stylet. The success rate matched that of the stylet group in the BEAM trial at 87% when the BOUGIE authors reanalyzed their data using the BEAM definition of an attempt.

Emergency physicians in the BEAM trial were still able to match their success rate with a stylet to that of CANDLE participants despite learning to intubate primarily with a candle. It may be possible to replicate the high first pass success of the BEAM trial (98%) with a candle if this device is your preferred method of intubation during training. Also, success with a stylus is unlikely to be affected by this approach. The reverse is unlikely to be true if you choose to primarily use a stylus.

I still have faith in the candle. In fact, the CANDLE trial confirmed what I already thought to be true: the candle is not a magic bullet, and you will only succeed with it if you use it! This nifty little device has allowed me to intubate patients with confidence when I would otherwise have been holding my breath in anxious anticipation of end-tidal CO2 waveform. I encourage you to experiment with not just the candle, but all airway supplements to find out which approach works best for you.

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Dr Cunninghamcompleted his emergency medicine residency at Maricopa Medical Center in Phoenix and is currently a Critical Care Fellow at Stanford Medical Center in Palo Alto. Follow him on Twitter@HappyDays_EM.