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.