Association of prehospital advanced airway management with neurologic outcome and survival in patients with out-of-hospital cardiac arrest.

Hasegawa K, Hiraide A, Chang Y, Brown DF.
JAMA. 2013 Jan 16;309(3):257-66. doi: 10.1001/jama.2012.187612.

LINK TO ABSTRACT

This will be an important study with a lot of implications for prehospital care for a number of reasons.

  • Prehospital Cardiac Arrest research has increased in amount and improved in quality over the last 5 years.

  • Most of these studies have come from prospectively designed registries such as this study.

    • Japan and Korea have both developed country wide registries.

    • Resuscitation Outcomes Consortium and the Cardiac Arrest Registry to Enhance Survival (CARES) are two examples in the US.

    • Long term survival with good neurologic status (and not just ROSC or survival to discharge) has become the standard measurement.

    • ACLS has relied on more and more of these registry studies to drive their clinical changes.  Randomized controlled studies will always be the gold standard but are difficult and expensive to accomplish.

Japan as a country has taken an aggressive stance to improve outcomes in cardiac arrest.  This has been manifested as a huge increase in the number of available public AED’s, improvements in EMS and hospital care, as well as a nationwide registry with one month survival outcomes for all cardiac arrest patients.

As they make improvements to their EMS system, Japan is asking questions about the utility of advanced airway management in out of hospital cardiac arrest patients.  The usual EMS crew has 3 personnel with one trained to lead a cardiac arrest, place an IV line, and use an AED.  Some agencies allowed the use of supraglottic airways (LMA or combitube) and others allowed with special training, the placement of endotracheal intubation.  This ET training consisted of 62 hours of training and a minimum of 30 supervised intubations in an operating room.

  • Over 600,000 Cardiac Arrest patients (cardiac and noncardiac etiology)

  • 57% received Bag Valve Mask

  • 43% received an Advanced Airway

    • 6% with an ET tube

    • 37% with a supraglottic airway

Advanced airway group had a lower rate of favorable neurologic outcomes as compared to the bag valve mask group (1.1% vs 2.9%;odds ratio [OR], 0.38; 95% CI, 0.36-0.39). 

  • The overall survival rate was this low because they included both cardiac and non cardiac causes.

  • The advanced airway group was not just a little worse but a lot worse.

  • This difference persisted even when other variables were accounted for.

  • This persisted even when they teased out the ET tubes and the supraglottic airways.

Why should this be the case?  With such a high use of supraglottic airway devices, it should not be misplacement of the tube.

Previous studies have clearly demonstrated that almost all humans have the propensity to hyperventilate almost all of the time in these high profile cases.  Hyperoxia and hyperventilation have both been demonstrated to worsen outcomes in these patients.

  • The State of Arizona is beginning training for all of their medics to limit the common and deleterious effects of hyperventilation in head injury patients.

  • Should we be doing this training for all of our airway patients?

  • Should we have prehospital ventilators to remove hyperventilation?

In the past, it has been very difficult to propose the prospective randomized study of airway versus BVM in cardiac arrest.  This study generates enough equipoise of this clinical question to make the argument for this future study more likely to be funded.

Dr. Sporer is the EMS Medical Director for Alameda County

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