Advertisement

Drowning: guidelines extant, evidence-based risk for rescuers?

      Sir,
      In recent editions of Resuscitation there has been an interesting and constructive debate on the topic of the rescue and resuscitation of submerged victims. This was prompted by a paper we wrote
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      which itself was prompted by a request for clear guidance on the issue from the emergency services.
      • Ramm H.
      • Robson B.
      Reference editorial – rescue and resuscitation or body retrieval.
      Our guidance was clear, qualified and specific to those that are submerged; as evidenced by the title “A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion”.
      On the basis of the available literature we concluded that, if water temperature is warmer than 6 °C survival/resuscitation is extremely unlikely if submerged longer than 30 min. If water temperature is 6 °C or below, survival/resuscitation is extremely unlikely if submerged longer than 90 min.
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      In a recent edition of Resuscitation, in an Editorial under the heading “Drowning: more hope for patients, less hope for guidelines”
      • Deakin C.
      Drowning: more hope for patients: less hope for guidelines.
      Professor Deakin reviews our guidelines in the light of two papers published in the same edition.
      • Claesson A.
      • et al.
      Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.

      Wanscher M, et al. Outcome of accidental hypothermia with or without circulatory arrest. Experience from the Danish Praesto Fjord boating accident. http://dx.doi.org/10.1016/j.resuscitation.2012.05.009.

      In contrast to Professor Deakin's conclusion, we can find nothing in the papers that changes our view, indeed just the opposite. It is important to understand how this position can come about, lest the issue gets clouded by semantics and confuses those still in search of clear, evidence-based guidance.
      In his editorial, Professor Deakin uses “immersion” and “submersion” interchangeably; the editorial also includes a somewhat ambiguous statement “.. it may be premature to abandon search and rescue efforts as soon as 30min after submersion in water above 6°C”. We must be clear about this; it is submersion (head under) that we are interested in rather than immersion (head out), and our paper refers to those who remain submerged in water warmer than 6 °C and have not been found despite 30 min of searching. Professor Deakin's statement could be misunderstood as meaning that if an individual has had a brief period of submersion at the start or end of an immersion, resuscitative efforts should not be undertaken if 30 min have elapsed – this is not our position. We are interested in when the risk to rescuers – which is likely to increase with time - may outweigh the likelihood of finding a submerged individual who can be resuscitated. It follows that this guidance is particularly pertinent in conditions that place rescuers at high risk.
      What do the papers reviewed by Professor Deakin actually add to the debate on the rescue and resuscitation of submerged victims? The answer is that neither paper provides data associated with prolonged submersion and subsequent survival that changes our original conclusion. The data of Claesson et al
      • Claesson A.
      • et al.
      Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.
      are insufficient to make conclusions concerning water temperature, however when reporting accidents where divers were required (submersions), they state (page 4, under “3.3.3. Survival”) “The median submersion time was 15min, no survivors were found after this time in the group with water temperatures >15°C”. This would seem to provide some support for our original conclusions which were based on cases of prolonged underwater survival (Fig. 1.
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      ). Further support is provided in a recent review on drowning
      • Szpilman D.
      • Bierens J.J.
      • Handley A.J.
      • Orlowski J.P.
      Drowning.
      (Table 2) in which the risk of death or severe neurological impairment after hospital discharge is given as “nearly 100%” when the duration of submersion exceeds 25 min. Finally, the findings of Wanscher et al

      Wanscher M, et al. Outcome of accidental hypothermia with or without circulatory arrest. Experience from the Danish Praesto Fjord boating accident. http://dx.doi.org/10.1016/j.resuscitation.2012.05.009.

      are probably irrelevant to the current debate as they conclude that in the cases they review, which occurred in 2 °C salt water without submersion, “circulatory arrest was most likely due to hypothermia rather than asphyxia (due to salt water aspiration)”.
      In his editorial Professor Deakin adds the median time taken for the rescue services to arrive at the scene in Sweden (8 min) to an immersion time of 20 min for survivors to conclude that this is a bit close (“pessimistic”) to 30 min, and warrants a longer rescue phase. However, our advice in this area, which arose as a recommendation (R Hackwell, Maritime and Coastguard Agency) from the consensus conference we ran on this subject,
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      is that the clock used to determine elapsed time is not started until the emergency services arrive on the scene. This is, necessarily, standard practice when a submersion is not witnessed (often the case
      • Claesson A.
      • et al.
      Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.
      ), and even if it is witnessed, this approach avoids relying on the memory of those that may be stressed and distracted at the time. In connection with this, Professor Deakin reports
      • Deakin C.
      Drowning: more hope for patients: less hope for guidelines.
      that Claesson et al
      • Claesson A.
      • et al.
      Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.
      found that “all survivors at one month (after cardiac arrest due to drowning) had been found within 20min of arrival of the emergency services and 75% of these within 10 min”. For those in this category that were submerged outside of a vehicle (n = 5, Table 4
      • Claesson A.
      • et al.
      Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.
      ), four were found “immediately” and one within 10 min. One person was found in a vehicle within 10 min, but we advise caution when dealing with these cases as they may be submerged in an air pocket and therefore have an extended underwater survival time
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      .
      So what are the facts at this time?
      • a.
        Despite the large number of submersions that occur, we are still seeking evidence that individuals submerged for longer than 30 min in water warmer than 6 °C survive. Until we obtain this evidence we remain of the view that this is “extremely unlikely” and believe our guidance remains extant.
      • b.
        That something does not happen (survival) when it has frequent opportunities to happen (accidental submersion >30 min in water >6 °C), constitutes strong evidence that it (survival) is improbable.
      • c.
        No evidence has been presented for the requirement to search for 60 min or 90 min in water warmer than 6 °C. This means that when conditions are extreme, rescuers may be put at risk without foundation.
      We re-iterate our previous conclusions
      • Tipton M.J.
      • Golden F.S.
      A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
      • Tipton M.J.
      • Golden F.
      Comments on editorial “rescue and resuscitation or body retrieval – the dilemmas of search and rescue efforts in drowning incidents”.
      : what we have produced should only be regarded as a guide, and local circumstances and/or clinical signs may dictate an alternative course of action to the senior medical responder at the scene. It is likely to be of most use when rescuers are placed at high risk by continuing a search and subsequent rescue attempt. We expected our paper to provoke discussion and possibly identify new information that may require the guidance to be amended and refined. The papers referenced by Professor Deakin do not appear to provide such evidence, we therefore remain content with the recommendations we have made, with the associated qualifications and caveats that can be found in our original paper.

      Conflict of interest statement

      Professor Mike Tipton: Patron of the SARbot UK charity, Member of the RNLI's Medical & Survival Sub-Committee.
      Dr Frank Golden: Nil return.
      Dr Patrick Morgan: Registrar Anaesthesia and Critical Care. Gloucestershire Royal Hospitals NHS Trust, Gloucester. Great Western Air Ambulance. COI: RNLI Medical and Survival Sub-committee, Medical advisor SLSGB.

      References

        • Tipton M.J.
        • Golden F.S.
        A proposed decision-making guide for the search, rescue and resuscitation of submersion (head under) victims based on expert opinion.
        Resuscitation. 2011; 82: 819-824
        • Ramm H.
        • Robson B.
        Reference editorial – rescue and resuscitation or body retrieval.
        Resuscitation. 2011; 82 ([author reply e5]): e3
        • Deakin C.
        Drowning: more hope for patients: less hope for guidelines.
        Resuscitation. 2012; https://doi.org/10.1016/j.resuscitation.2012.06.004
        • Claesson A.
        • et al.
        Characteristics of lifesaving from drowning as reported by the Swedish Fire and Rescue Services 1996–2010.
        Resuscitation. 2012; https://doi.org/10.1016/j.resuscitation.2012.05.025
      1. Wanscher M, et al. Outcome of accidental hypothermia with or without circulatory arrest. Experience from the Danish Praesto Fjord boating accident. http://dx.doi.org/10.1016/j.resuscitation.2012.05.009.

        • Szpilman D.
        • Bierens J.J.
        • Handley A.J.
        • Orlowski J.P.
        Drowning.
        New Engl J Med. 2012; 366: 2102-2110
        • Tipton M.J.
        • Golden F.
        Comments on editorial “rescue and resuscitation or body retrieval – the dilemmas of search and rescue efforts in drowning incidents”.
        Resuscitation. 2011; 82 ([author reply e5]): e1