Cardiac Arrest? Hold off on that ET tube

It’s a quiet night in the critical care area of the ED, and you are engaging in stimulating and academic discussion with your attending and junior resident about the merits of cinema in the 1980s. Just as you broach the subject of Steven Spielberg’s ET the Extra-Terrestrial, the red phone rings. Your junior picks it up.

“Mm hmm,” he mumbles into the phone, jotting down vital signs in calligraphic handwriting into the impeccably kept trauma log sitting on the spotless countertop.

“ETA five minutes… Witnessed cardiac arrest… ROSC achieved… ET tube in place,” he says as he hurries towards the resuscitation room to check the airway equipment.

After waiting 15 minutes and briefly wondering if EMS has taken a wrong turn and ended up at Methodist, the double doors fly open.

EMS is here. Surprise!

In rolls an elderly woman, with EMS actively doing chest compressions and bagging a patient that very much does not have an ET tube in place.

“Unwitnessed arrest… Found down. We’ve been working on her for 10 minutes. No ROSC,” pants the paramedic, as he compresses the patient’s chest. “We didn’t have time to go for the tube.”

Throw that tube in?

You transfer the patient off of the gurney and onto the bed. The nurses seamlessly obtain IV access and place the patient on a monitor with absolutely no direction required. The rhythm is PEA. Your junior, ever procedure-minded, already has suction ready with a laryngoscope in hand and a “styletted” ET tube tucked into the bed sheet for easy access. He looks at you through his face shield for the go-ahead.

The idea behind securing the airway in the pulseless patient is to facilitate continuous chest compressions while simultaneously delivering air to the patient’s lungs (excluding respiratory arrest, where intubation and mechanical ventilation may be required to treat the hypoxemia and/or respiratory acidemia). However, intubating typically does necessitate an interruption in compressions to allow visualization of the larynx and passage of the tube (note, this is not necessarily true for supraglottic airway devices).^[1] Remember that during cardiac arrest, oxygen delivery is mainly dependent on perfusion (and therefore good CPR) rather than ventilation.

It’s difficult to design a true RCT evaluating this practice for obvious ethical issues, but there is some data. One supportive study out of Korea cohorted 32,513 patients from a database of out-of-hospital cardiac arrests and compared Endotracheal Intubation (ETI) to Bag-Valve-Mask (BVM) ventilation. The study found higher long-term survival amongst those intubated, although this group included more witnessed arrests (53% compared with 43% in the BVM group).^[2] A smaller study in Taiwan on in-hospital arrests also agrees with these findings.^[3] Additionally, a third study on 702 patients (also from Korea) that were intubated post-arrest found that patients intubated earlier after first chest compression were more likely to survive and more likely to have a favorable neurological outcome.^[4] This suggests that if you’re going to pull the trigger on ET intubation, you should pull it fast.

What to do???

...Or not

“Hold the tube and continue compressions,” you direct. You take a moment, pause, and drum your fingers on the edge of the bed as you continue to run through the data in your head (along with those “Hs and Ts”).

The studies supporting peri-arrest intubation are by no means definitive. A prospective cohort study on 649,654 patients in Japan who underwent intervention for out-of-hospital cardiac arrest (OHCA) found that neurological outcome and well as short-term and long-term survival were improved if EMS personnel used a BVM compared to intubation. It didn’t seem to matter if it was traumatic or non-traumatic, or if multiple attempts were required.^[5]

It doesn’t seem to matter if supraglottic airways like the LMA are used, either. A meta-analysis of 17,380 patients that received advanced airways (intubation or supraglottic) fared worse in terms of survival than those that were “bagged”.^[6] A similar review of 388,878 patients across 17 different studies came to a similar conclusion.^[7]

Bagged patients may do better.

It also doesn’t even seem to matter why they arrested. A matched cohort study on 16,278 traumatic brain injury patients who were intubated in the prehospital setting found that intubated patients required longer ICU stays and had a higher mortality in additional to longer transport times.^[8] Another cohort study on 1,294 OHCA patients for any cause found poorer survival amongst those intubated, even controlling for initial rhythm, witnessed vs unwitnessed arrest, and bystander CPR.^[9]

But we’re no longer in the field, and my junior is salivating in anticipation!

Although ED intubation for OHCA hasn’t specifically been studied, there is ample data on witnessed, in-hospital cardiac arrests. A recent, matched cohort study on 108,079 such patients across 668 institutions found a 16% survival rate amongst those intubated compared with a 19% survival rate amongst those who were not.^[10] A similar cohort study on 2294 pediatric patients found that intubated patients had a 36% survival rate to discharge, compared with 41% of those not intubated.

What to do, what to do?

All better.

You perform one round of chest compressions, and direct your junior to place an LMA during the next rhythm check. The patient achieves ROSC after two more round of compressions and some epinephrine but unfortunately does not regain respiratory independence. Your junior resident then happily gets to place an ET tube prior to transfer to the ICU.

The take-away

Don’t immediately jump to intubation as the patient rolls in the door unless you have reason to believe the arrest was due to respiratory failure or airway obstruction. Treat any other causes of arrest and concentrate on compressions while using a BVM. It’s not unreasonable to place an LMA during a rhythm check or even during compressions. If you’ve tried everything else, kitchen sink that advanced airway into the patient’s trachea.

Ongoing Trials

The subject of supraglottic airways vs ETI performed by EMS personnel is currently being evaluated in a large RCT in the UK. Stay tuned and check out the AIRWAYS-2 trial currently underway: http://www.airways-2.bristol.ac.uk/

^[1]Decaen AR, Guerra GG, Maconochie I. Intubation During Pediatric CPR. Jama 2016;316(17):1772.

^[2]Kang K, Kim T, Ro YS, Kim YJ, Song KJ, Shin SD. Prehospital endotracheal intubation and survival after out-of-hospital cardiac arrest: results from the Korean nationwide registry. The American Journal of Emergency Medicine 2016;34(2):128–32.

^[3]Fan Y-J, Dai C-Y, Huang D-C, Wang M-L. Does tracheal intubation really matter? Discrepant survival between laryngeal mask and endotracheal intubation during out-of-hospital cardiac arrest. Journal of the Formosan Medical Association 2017;116(2):134–5.

^[4]Wang C-H, Chen W-J, Chang W-T, et al. The association between timing of tracheal intubation and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study. Resuscitation 2016;105:59–65.

^[5]Hasegawa K, Hiraide A, Chang Y, Brown DFM. Association of Prehospital Advanced Airway Management With Neurologic Outcome and Survival in Patients With Out-of-Hospital Cardiac Arrest. Jama 2013;309(3):257.

^[6]Jeong S, Ahn KO, Shin SD. The role of prehospital advanced airway management on outcomes for out-of-hospital cardiac arrest patients: a meta-analysis. The American Journal of Emergency Medicine 2016;34(11):2101–6.

^[7] Fouche PF, Simpson PM, Bendall J, Thomas RE, Cone DC, Doi SAR. Airways in Out-of-hospital Cardiac Arrest: Systematic Review and Meta-analysis. Prehospital Emergency Care 2013;18(2):244–56.

^[8]Haltmeier T, Benjamin E, Siboni S, Dilektasli E, Inaba K, Demetriades D. Prehospital intubation for isolated severe blunt traumatic brain injury: worse outcomes and higher mortality. European Journal of Trauma and Emergency Surgery 2016;

^[9] Hanif MA, Kaji AH, Niemann JT. Advanced Airway Management Does Not Improve Outcome of Out-of-hospital Cardiac Arrest. Academic Emergency Medicine 2010;17(9):926–31.

^[10] Andersen LW, Granfeldt A, Callaway CW, et al. Association Between Tracheal Intubation During Adult In-Hospital Cardiac Arrest and Survival. Jama 2017;317(5):494.