iPhoneIcon_BigA study in SJTREM compares CPR hands-off times with various airway devices. It reinforces what we already know. In order to maintain hands-off times within CPR guideline recommendations the endotracheal tube is not a realistic option for inexperienced EMTs.

CPR guidelines emphasize minimal hands-off time as it translates into increased survival. High quality chest compressions should be initiated as early as possible and be maintained with as little interruption as possible. Guidelines also recommend establishing a secure airway. This should be done with compressions ongoing or during a brief pause in compression no longer than 10 seconds in order to maintain hands-on time.

How we secure the airway can have great effect on hands-off time. The ETT is still the gold standard. An experienced intubator can often perform an endotracheal intubation with compressions ongoing and no hands-off time. An inexperienced intubator might struggle and hands-off time might be precariously prolonged or the tube may be misplaced in the oesophagus.

Most paramedics do not intubate that much. Endotracheal intubation requires training and re-training.  Furthermore, intubations in the critically ill are likely to be difficult intubations. That is why many emergency services have opted to use supraglottic airway devices (SAD) instead, as they most of the time are a quicker and easier way to obtain a secure airway. SADs also require minimal training compared to ETTs.

The study
40 EMTs with only basic airway skills were given an lecture and a practical demonstration of intubation using five different SADs as well as conventional ETTs. They then went through a CPR scenario in pairs where one EMT did the compressions and the other one was responsible for securing the airway using the six devices in a randomised order.

Each airway attempt should primarily be done with compressions ongoing. If not it should be performed during a 10 second brief pause. For attempts lasting longer than 10s, the attempt was abandoned in lieu of BVM-ventilation for 2 minutes before a new attempt was made. A maximum of three attempts were allowed before it was deemed a failure.

Overall hands-off time until the airway was secure was the primary end-point. The number of successful and failed attempts were recorded as well as unrecognised misplacements.

The study was repeated after one and three months.

handsoffHands-off times are in the graph. Its obvious how the EMTs struggled considerably with the endotracheal tubes from the start. It got somewhat better after one month but then worse again at three months, perhaps reflecting the constant need for re-training.

In fact, in the first session, only one out of 40 EMTs successfully intubated within 10s.

The SADs performed considerably better, all reducing average HOT to less than 20 seconds and then improving after one and three months.

The laryngeal tube stood out as the fastest with hands-off times averaging 8,4s.

All the SADs had success rates within three attempts of 100% at one, two and three months.  The ETT success rate, using three attempts was 35% in the first session, but improved to 58% and  70% in the later sessions. Unrecognised esophageal misplacement for the ETT was 20% in the first session and 15% in the last session.

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Take home message
This is yet another demonstration of how conventional endotracheal intubation, in the hands of inexperienced intubators,  results in hands-off times that by far exceeds guideline recommendations. Even more alarming are the many failed attempts and unrecognised misplacements.

The study lives here:

Scand J Trauma Resusc Emerg Med. 2013 Feb 25;21:10. doi: 10.1186/1757-7241-21-10. Evaluation of airway management associated hands-off time during cardiopulmonary resuscitation: a randomised manikin follow-up study. Gruber C, Nabecker S, Wohlfarth P, Ruetzler A, Roth D, Kimberger O, Fischer H, Frass M, Ruetzler K.

This entry was posted in Airway management, CPR, ECLS, Emergency Medicine, Prehospital Medicine, Tech. Bookmark the permalink.


  1. Andy Buck says:

    Good study to show that SGA’s reduce hands off time, which is good for your chances of ROSC, but getting an output back is less likely to occur if your lungs are completely full of vomit. Have had several cases of patients brought into ED with out of hospital arrests with vomit spurting through and around the LMA (placed by EMS), and on laryngoscopy, their breakfast/lunch/dinner coming back up through the vocal cords, and clearly this is unsurvivable. It’s a balancing act: aspiration risk vs hands off time. I don’t think there will ever be a “right” answer.

    • K says:

      Hi Andy,
      You are absolutely right. As mentioned previously on the blog I am very sceptical of SADs. This study is very convincing though. Hands off times improve considerably with SADs. Still other studies cant seem to demonstrate any survival benefit…

  2. Minh Le Cong says:

    good point Andy but those cases you cited prob should never have been transported to your ED in first place! they should have been called onscene..unless you meant they had ROSC prehospital and got transported to ED with ROSC?
    ideally we should be using SGA/LMA that have an oesophageal drainage port/channel and the ability to intubate via the main ventilation channel.

    also using mechanical CPR devices is going to make things more efficient for prehospital cardiac arrest resuscitation. frees up a pair of hands and does compressions better and longer than any human.
    this allows airway interventions to be done with more focus and care.

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