Monday, June 17, 2013

Effectiveness and safety on in-water resuscitation performed by lifeguards and laypersons




Effectiveness and safety on in-water resuscitation performed by lifeguards and laypersons: A crossover manikin study
Authors: Winkler B, et al.
Journal: Prehospital Emergency Care, July/September 2013

By focusing on hypoxia as our primary cause of systemic injury in the drowning patient, it goes without saying that we should try and reverse it as fast as possible.  It makes sense that providing oxygenation to the patient as soon as possible, even if still in the water, would improve overall outcome.  This positive effect was shown in the only major study on the subject by Dr Szpilman in 2004.  Despite these findings, primarily due to the fact that in-water resuscitation (IWR) is a difficult intervention to perform, there is still question about whether this should be standard treatment.  Current ERC and AHA guidelines call for its use, but specify that it should be done only if it doesn't greatly delay overall treatment/transport and if the rescuer is comfortable performing the task.

Dr Winkler, who previously authored a study on the use of various airway adjuncts in the water, reports his findings on a study using the same study set up, which is designed to measure total rescue time, number of airway submersions, and amount of water aspirated by a simulated manikin victim during the rescue.  This study was primarily focused on evaluating the effectiveness and difficulty of performing IWR, compared with non-ventilation (NV) rescues, using both trained lifeguards and lay-persons.

Important findings:

  • IWR significantly increased rescue time, number of submersions, and volume of aspirated water
    • Lifeguards had significantly better rescue times with IWR and NV
    • No difference in two groups in terms of aspiration with IWR
  • Lifeguards performed significantly better IWR (Tidal volume and minute ventilations)
    • Lifeguards had relatively constant tidal volumes, slightly above recommended volumes
    • Lay-persons had progressively decreasing volumes through out rescue
  • Both groups reported increased difficulty when performing IWR
In terms of how this affects my practice, I don't think the evidence is present to justify performing IWR on all victims or making it standard for all lifeguards to perform.  The current thought by leading experts is that IWR should be attempted if the estimated time to shore or boat is > 5 minutes, and I tend to agree.  I do however think that there is enough evidence for the improved outcome with early ventilation and for the feasibility of IWR to perform 2 breaths, signal to your land-based team, and then begin bringing the patient in.  The most important factor is the confidence and physical capabilities of the rescuer.  This study was performed in a controlled/simulated environment which cannot come close to matching the mental, physical, and environmental stress of a real-world rescue.  All in all, a well designed study to meets the intended goals, and another piece of evidence to keep in the back of our minds.

Source:

6 comments:

  1. We used to practice IWR as part of the 'downed diver' drills in Carmel CA (Monastery Beach and Carmel River) ... serious stuff, w/surf mat while swimming through the kelp beds ... www.ucdivers.com [interesting anecdote: glenn seaborg, the principal discoverer of plutonium in the twilight of his career, emeritus having had a modicum of success ;) was the head of the scientific diving control board when i was certified at UC Berkeley as a 'scientific research diver' ... he actually signed my original dive card!

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  2. There is no evidence to support that giving 2 breaths will improve outcomes if the patient is in full cardiac arrest; it is probably beneficial if the patient is just in respiratory arrest but how do you differentiate in the water? The AHA/ERC have "hung their hats" on low grade evidence/expert opinion. Furthermore, a number of so called drownings are actually primary cardiac arrests; the only thing that will counter VF/VT in this setting is a shock from a defibrillator. Mucking around with clearing the airway, applying suction, waiting for a bag-mask/oxygen to arrive or be assembled delays application of CPR. What we should be teaching is that an unresponsive, non-breathing patient should be returned to shore immediately, chest compressions started and then attach ventilation adjuncts/suction to the patient around this activity (but not in place of it). Teaching lay-persons IWR is a nonsense; not only are most lifeguards not trained in IWR, but even those that are would find it very difficult in a 'real world' situation. Drowning is a different disease process from primary cardiac arrest, but perpetuating the myth that the resuscitation of a drowned person is "different" is actually unscientific to some extent and may result in delayed application of CPR, AEDs etc. leading to worse patient outcomes. All victims of cardiac arrest need chest compressions, ventilations and an AED attached; what makes drowning so special - perhaps it isn't, and some people can't let go of that belief??

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  3. Thank you for your response. A few comments I have. Yes underlying cardiac disease can lead to drowning, but in no way is it the majority of cases. I believe you have to see drowning as a different disease process because it is. When it gets lumped into the "cardiac" causes of injury and death it runs the risk of being treated the same by lifeguards and the lay rescuer. I have lectured on this topics to about 1000 lifeguards/military/medical personel/lay-people over the past few years and I am surprised how many of them don't understand this and don't know that drowning should still be treated with ABC paradigm and not CAB. I couldn't agree with you more about additional tasks which unfortunately delay ventilations, and I always stress this in my teaching. I share some of your beliefs on large-scale standards and the organizations that make them, but they are the standard and well-known. In my own practice, since it may take 10 seconds to get your bearing, make an exit plan, and signal to the beach, I would advocate giving some breaths in that time, not because I have exact evidence to back it up, but because I think it would be better than nothing. I agree teaching IWR to the lay-person is a bad idea, and when teaching lifeguards it should be stressed which situations it may be useful in. Once again, thanks for your comments and critical thinking.

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  4. The inference is that using CAB vs. ABC is to the detriment of the patient and it is here we are selling people a half or complete untruth. In other words, what we are saying is if you take 2 identical twins with the exact same health status, drown them, pull them both out of the water at the same time and give the first twin 2 breaths, followed by 30 compressions while at the same time the other twin gets 30 compressions followed by 2 breaths that the twin who had breaths first is going to do better than the one who had compressions first. And we are not in any position to do that. So, what is the actual "risk" of treating drowning the same as primary cardiac arrest if patients get timely application of CPR (full CPR, not chest compression only) and an AED attached to them? I would contend there is little to no risk, and while the aetiology of drowning is different, those of us who work in aquatic safety would prefer to hold on to a long-held belief that drowning resuscitation is "different", when perhaps it is not all that different at all? Appreciate your comments.

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  5. My viewpoint is that people need to fully understand the underlying pathophysiology so they dont follow new mantras of "compression only CPR". Obviously this won't happen much with our professional rescuers, but I hammer in this difference so when they are asked by a lay-person or when they train lay-people, they emphasize the importance of utilizing ventilations in the CPR.

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  6. No argument the chest compression only CPR is not want we want in drowning. :)

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