CPR: MAN VS MACHINE: 1-1

My name is LUCASAre mechanical chest compression robots better than your average ambo? The LINC trial in JAMA seeks to answer that. LUCAS, probably the most popular mechanical chest compressor, has been tested in a study against man. 2.600 patients randomised to man or machine for out of hospital cardiac arrest (OHCA).

The study
Nearly 2.600 OHCA patients were included on-scene by ambulance crew and randomised to LUCAS CPR or manual CPR. Centres in Sweden, UK and the Netherlands contributed. Primary outcome was survival after 4 hours – basically seeing how many patients got ROSC. Secondary outcome was good neurological outcome after 6 months. Both good markers for CPR outcome.

Results and discussion
It was even. For both primary and secondary outcomes. Meaning LUCAS won’t bring more of your patients back to life nor preserve their brains better than your average ambo. Both arms had a good 23% ROSC. Decent numbers, but this was only after the ‘obviously dead’ on ambulance arrival were excluded.

Numbers to note are that 5 patients in the manual CPR group crossed over to LUCAS for transport: To maintain rescuer safety and let them strap in their seat belts instead of riding the patient in a speeding ambulance. But also, 46 of LUCAS patients crossed over to manual CPR group as the device wouldn’t fit the patient. Small numbers, but something to keep in mind.

You’ll also find that times to first shock, to ROSC and to transport were all longer in the LUCAS group. The authors contribute some of this to their mechanical algorithm that demanded 90 secs of LUCAS before first shock, but probably also due to extra fiddling with the LUCAS in place. It is rarely as smooth as in the promo video below.

Hands-on defibrillation
The trial also compared the standard CPR algorithm to the theoretically advantageous defibrillation-during-compressions with LUCAS.

This would help minimise hands-off time, but the compressions were still stopped every 3 minutes to do rythm checks. Anyway, any slightly shortened hands-off time did not translate to better ROSC or brain survival for the patients in this trial.

Can you trust LUCAS?
A short look at LUCAS’ performance: LUCAS is a mechanical device, and it failed for some reason or another in 8 cases. In another 7 cases, the device had to be repositioned. It is a known problem that LUCAS can slip/move during compressions, and you need to keep an eye on it. LUCAS can look quite violent as it compresses, but only very few adverse events were noted, and not significantly more than in the manual compression group. All in all, LUCAS seems dependable and safe – but not better.

Potential uses for LUCAS
So LUCAS won’t give you better outcome in a standard CPR setting. But LUCAS can be good for ambulance transports with patients in arrest. For in-hospital transports it shouldn’t be needed: a compressor straddling the patient on the gurney should do the trick. LUCAS is also used in refractory arrests during PCI, but they rarely have good outcome. It seems like LUCAS can only be advocated when logistics or rescuer safety demand it – not for superior CPR.

Conclusion
Ambos are as good as robots. Stick to the manual compression show. LUCAS is not for better CPR, but to facilitate transport.

Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest: The LINC Randomized Trial, JAMA, Nov 2013.

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7 Responses to CPR: MAN VS MACHINE: 1-1

  1. Sebastian says:

    The results surprised me. Thought it would be a lot better in the LUCAS group. But even if the outcome isn´t better it still has it advantages. As you mentioned its good for transports (only way to get a decent CPR in a helicopter I think).
    An additional plus is that it gives you tie to think instead of pumping. This won´t reflect that much in the pre hospital setting like in this study, but I´m pretty sure it does in the ICU, OR, Cath lab… Would like to see in hospital study too.

    • Thomas D says:

      I’m not sure. Pre-hospital is usually where you’re missing hands. For a cardiac arrest in-hospital, I find the problem is getting people to leave the room. There’s always someone who can do compressions while you think. And they can keep going until ROSC or until it’s futile.

      Of course, the optimal time-buying machine to let you think is to get real circulation by putting the cardiac arrest patient on V-A ECMO – where it’s available.

      • Christopher says:

        In my pre-hospital service area, EMS has taken ownership of OOHCA using a “pit crew” method. Effectively this means we should never have a shortage of on-scene resources to manage the arrest. Even in the more rural areas, you’ll see 2+ paramedics and 3+ lower level providers available.

        If an area takes OOHCA seriously, they should never have less than 4 persons on the call. This is the minimum needed to effectively manage an arrest with manual CPR.

  2. …but in areas where < 3 people avail (inc doing airwya, access, drugs, defib) and long transport (rural), I reckon LUCAS is the go

    I wonder if China could make them cheaper?

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