Systematic reviews

Recognition of drowning by a lay-person 

A systematic review on the recognition of drowning including the visual cues or signs a layperson can use to identify a drowning person was conducted and identified 23 studies (Pascual-Gomez & Petrass, 2020). The review highlights there is very limited empirical data describing how laypeople recognise a person is in the early stages of the drowning process. The review therefore also draws on limited data describing how lifeguards recognise drowning. 

One study found that lifeguards are commonly taught to look for a specific set of behaviours that are considered to show drowning or distress situations, including splashing, frequent submersion, changes in body position, impairment of swimming effectiveness, and a lack of progress through the water. 

Another study found that given the drowning person’s rapid progression from distress to submersion, recognition of even earlier signs of distress is critical, for example, a swimmer moving slowly due to weakness, physical condition, or fatigue or moving into water beyond their skill level. 

A separate study found that lay people were especially good at identifying even earlier events that can lead to drowning, for example, children performing dangerous activities, such as repeated submerging, horseplay, or going too far from shore. Lay people need to be educated on behaviours that characterise distress in the water or drowning. 

Results indicate that a person shows some or all of the above behaviours in almost all instances of drowning. However, as these behaviours are common in water settings, it may be challenging for bystanders to recognise them.

No studies reviewed addressed the fact that some drowning people display no signs.

The review made recommendations based on the very-limited and limited evidence available as well as based on best practice and consensus expert opinion.

Water rescue equipment

A scientific review addressing the question of what the most effective types of aquatic rescue equipment for a layperson or bystander to use to rescue a drowning person was updated in 2019 (Beale-Tawfeeq, 2019). It reported a lack of evidence identifying which items can be recommended based on accuracy, buoyancy, the distance that they can be thrown, and ease with which they can be caught by the drowning person. Despite the limited data, the review puts forward the current recommendation of rescue equipment including throw ropes and lines and ring buoys for effective use by bystanders which seem to contribute to positive outcomes. 

Bystander CPR

The International Liaison Committee on Resuscitation (ILCOR) Basic Life support task force carried out a scoping review on resuscitation and emergency care in drowning (Bierens et al., 2021). It included 65 studies, of which 19 observational studies were identified that discussed bystander CPR as an intervention following drowning. Statistically significant associations were found with improved neurological outcomes (two studies), survival (four studies), however other studies either found a positive trend towards survival, or no association. Three studies compared compression-only CPR with conventional CPR and all favoured conventional CPR with bystander ventilation in terms of neurological outcomes and survival. Based on this evidence, initiating conventional CPR which includes ventilation and compressions is recommended.

Automated external defibrillator use in drowning

The ILCOR scoping review (Bierens et al., 2021) searched for studies reporting impact on outcomes from the use of an on-site automated external defibrillator (defibrillator) in cardiac arrest due to drowning prior to the arrival of emergency medical services but no studies were identified.

Indirect evidence of defibrillator use was found from 15 observational studies. In four studies there was a range of defibrillator use in cases of suspected drowning prior to the arrival of EMS. In 12 studies it was uncommon to detect a shockable rhythm. Seven observational studies found that a shockable rhythm was not associated with the outcome of better survival. One study found there was an association between shockable rhythm and increased 30-day survival. One study found the use of defibrillators on boats in moderate sea conditions to seem feasible. One study with lifeguards reported the mean time from arrival to defibrillation was 62 seconds. There was one case of inappropriate shock delivered to a person in an asystole in one study, with no obvious consequences. There were no adverse events identified in any of the studies listed.

Oxygen use

The ILCOR scoping review also searched for studies about the pre-hospital use of oxygen following a submersion incident, but no studies were identified (Bierens, 2021). Indirect evidence from observational studies found associations between hypoxia, oxygen administration and worse outcomes. In the absence of specific research about the use of oxygen in drowning, ILCOR concluded that the existing treatment recommendation for oxygenation after the return of spontaneous breathing applies. This guides to avoid hypoxaemia and hyperoxia, using 100% inspired oxygen until arterial oxygen saturation or the partial pressure of arterial oxygen can be measured. If the person is breathing normally, supplemental oxygen with a target saturation of 94–98% for a person who has drowned may be used.

In-water resuscitation

Five studies were identified by the ILCOR scoping review on the topic of in-water resuscitation (Bierens et al., 2021). The evidence indicates that in-water resuscitation (composed of rescue breaths only) is very challenging and should only be attempted by highly-trained rescuers if it is safe to do so. Therefore, the emphasis for first aid providers should be on non-contact rescue rather than in-water resuscitation.

One clinical study used a protocol of giving up to one minute of ventilation before moving the unresponsive person to shore and in deep water required either the availability of a flotation aid or at least two rescuers. Initial survival, survival to hospital discharge and favourable neurological outcome were all rated higher for in-water resuscitation. The other four studies evaluated the capacity of lifeguards and laypeople to perform in-water resuscitation and rescue of a manikin. In-water resuscitation was technically difficult and physically demanding, particularly in open water. It increased the rescue time, number of submersions and breathing-in of water by the manikin. Some trained lifeguards and laypeople were unable to complete the rescue. ILCOR found that the use of ventilation adjuncts by well-trained lifeguards might facilitate in-water resuscitation.

Resuscitation on a boat

The ILCOR scoping review (Bierens, 2021) found seven studies that evaluated resuscitation on a boat. One case series looked at the outcome of survival from resuscitation on a boat (24 cases) and found no survivors. However, the CPR quality was reported to be sub-optimal. In the other case series, six resuscitations were attempted on a boat or lifeboat; there was only one survivor after one month. Four studies evaluated the capacity of lifeguards and fishermen to perform CPR in inflatable rescue boats or fishing boats. The studies showed that CPR was physically demanding but that resuscitation on a boat was feasible. The quality of the resuscitation was affected by the boat speed and the sea conditions with ventilations more affected than chest compressions. One simulation study showed that defibrillator use on rigid inflatable rescue boats on calm water was feasible. 

Advanced airway management

In the ILCOR scoping review, no studies were identified that examined the effect of a particular airway management strategy over another or no intervention, in the management of a submerged person (Bierens et al., 2021). However, six observational studies indirectly examined airway management strategies in people following drowning events. In all studies, intubation was an indication of the severity of the injury, with the most severe cases being intubated during cardiac arrest or facilitated with anaesthesia. Two studies showed intubation was associated with worse outcomes and one study did not find an association between intubation and long term mortality. One study showed mobile medical team ventilation as associated with better outcomes.

 Prognostic factors that predict drowning outcomes

In 2020 ILCOR updated the systematic review for prognostic factors that predict outcomes concerning drowning incidents such as duration of submersion, the person’s age, the salinity of the water, and water temperature, compared with no factors (Olasveengen et al., 2020). The review recommended that submersion duration be used as a prognostic indicator when making decisions surrounding search and rescue resource management or operations. 

– Submersion duration

Studies were considered to look at survival with favourable neurological outcome for different lengths of time of submersion (short – less than 5-6 minutes, intermediate – less than 10 minutes, and prolonged – less than 15-25 minutes). All studies noted worse outcomes associated with submersion duration longer than 5 minutes. The 2020 update was consistent with the 2015 review which found that submersion durations of less than 10 minutes are associated with a very high chance of favourable outcomes, and submersion durations of more than 25 minutes are associated with a low chance of favourable outcomes.

 For the duration of submersion, the review and meta-analysis identified:

• For short submersion intervals (less than five to six minutes) moderate-certainty evidence was identified from 15 observational studies for the critical outcome of favourable neurological outcome and a low-certainty of evidence. All studies noted worse neurological outcomes in people with submersion durations of more than five minutes.  For the critical outcome of survival, low-certainty evidence was identified using six observational studies. All studies had an association between worse survival outcomes among people with prolonged compared to short submersion durations.
• For intermediate submersion intervals (less than ten minutes) there is moderate-certainty evidence based on nine observational studies for the critical outcome of favourable neurological outcome and low-certainty of evidence from two observational studies for the critical outcome of survival. All studies noted worse neurological outcome among patients with prolonged submersion durations compared with intermediate submersion durations.
• For prolonged submersion intervals (less than 15 to 25 minutes) there is low-certainty evidence for the critical outcome of favourable neurological outcome from three observational studies and very low-certainty evidence for the critical outcome of survival from a single study. Submersion of less than 20 or 25 minutes was associated with better neurological outcome versus longer submersion duration for adults and hypothermic children. Cases with a submersion interval of fewer than 15 minutes had a higher overall survival rate.

– Age, salinity and water temperature

For age, salinity and water temperature there was very-low-certainty or contradictory evidence for the critical outcomes of favourable neurologic outcome and survival.

– EMS response interval

For the critical outcome of survival, there is low-certainty evidence from two observational studies. EMS response intervals of less than ten minutes were associated with better survival outcomes. 

– Witnessed status

The review found that the definition of witnessed compared with unwitnessed drowning was inconsistently defined in the studies reviewed. It was often unclear if the term “witnessed” related to the submersion or the cardiac arrest. 

For the critical outcome of survival with favourable neurological outcome, there is very-low-certainty evidence from three observational studies, showing better outcomes for witnessed drownings. However, the studies did not indicate submersion duration which has been identified as an independent indicator of prognosis. 

For the critical outcome of survival, there is low-certainty evidence from four studies. The evidence is variable and contradictory, and one study could not be generalised. 

Non-systematic reviews

Water rescue equipment

The scientific review outlined above by Beale-Tawfeeq (2019) addressing the question of the most effective types of aquatic rescue equipment for a layperson or bystander to use to rescue a drowning person also recorded some expert opinion.  It recommended that teaching rescue skills should become a part of water safety classes and guidelines to reduce the rates of drowning. It also recommended that targeted interventions are needed to address rescue skills in multiple aquatic environments, particularly those that are high risk. And that the development of public-access safety programs may help improve drowning outcomes. 

Finally, the review also reflected on the sentiment of “rescuer altruism” in a layperson or bystander when a person needs rescue from the water; they will initiate rescue despite the danger to themselves. 

Lay-rescuers techniques in drowning incidents

A scoping review (Barcala-Furelos et al., 2021) to identify the safest techniques and equipment for an untrained bystander to use when attempting a water rescue included 22 studies. The review identified three types of techniques used by laypersons:

• non-contact techniques for rescue out the water: throw and reach
• non-contact techniques for in-water rescue using flotation aids
• contact techniques for rescue in the water: swim and tow with or without flippers

It stated that the safest technique for a lay-rescuer is the first one – to attempt non-contact rescue using a pole, rope, or flotation equipment without entering the water. 

Despite the recommendation that an untrained person should not enter the water to rescue a drowning person, the literature shows a human tendency towards “altruism” in helping a drowning person. In most incidents, a rescuer entered the water and made contact with the drowning person, putting themselves at risk. This behaviour was especially manifested when the rescuer had a close bond with the drowning person. However,  in many cases, witnesses took risks to help someone they didn’t know, based on the principles of the Good Samaritan and the desire to “do the right thing”.

The review suggests it may be difficult to prevent the impulse of lay-rescuers to enter the water but it is possible to encourage potential rescuers to carry some sort of flotation aid if they attempt a rescue. Studies in the review identified that the teaching of rescue techniques in school should be ongoing if the skills are to be retained in adult life. 

Removal of fluid

There is no indication that water blocks the airway as a foreign body. Manoeuvres such as abdominal thrusts to relieve foreign body airway obstruction are therefore not recommended for people who have drowned (International Life Saving Federation, 2016). Such manoeuvres are unnecessary and may cause injury, vomiting, and delay CPR.  Resuscitation with rescue breaths should begin immediately rather than attempting to remove fluids from the airways.

Little, if any fluid can be removed from the airways by drainage techniques (suctioning, abdominal thrusts or postural drainage). This is because the estimated amount of water breathed in is small and, after just a few minutes of submersion, it is absorbed into the circulation (Golden, Tipton & Scott, 1997). However, autopsy studies show large amounts of swallowed water in the stomach. Therefore procedures for foreign body airway obstruction should be used only if the airway is completely obstructed by a solid object. 

Positioning of an unresponsive person who is breathing

Szpilman (2012) recommends placing the breathing person on their side in the recovery position, with their head positioned to allow free drainage of fluids. The position should be stable, without pressure on the chest.

Spinal injury in instances of drowning

A person who is drowning is at risk for a spinal injury only if they have also sustained a traumatic injury or been involved in a high impact activity (such as diving, water skiing, surfing, or being caught in moderate to severe surf breaks). Routine spinal immobilisation does not appear to be warranted solely on the basis of a history of submersion (Watson, 2001). 

The International Life Saving Federation (2016) recommends that in the case of drowning as a result of a traumatic injury, if the person is unresponsive, management of their airway takes priority over any suspected spinal injury. The person can be handled to minimise spinal movement if possible. If the person is responsive, the principles of minimising movement apply and if removal from the water is necessary, then it should be done while maintaining alignment of the spine. 

Education review

Prevention of drowning

A paper by Denny et al. (2019) summarised factors contributing to the incidence of drowning in the USA and then made recommendations to prevent drowning. These strategies to prevent drowning are particularly relevant to education and advocacy. 

Factors contributing to drowning in the USA included the populations of young children 0-4 due to unsupervised access to bodies of water and adolescents who may overestimate their water competencies, undertake risky behaviour, or maybe affected by alcohol. Underlying health conditions such as epilepsy, cardiac arrhythmia and autism also increase the risk of drowning, with socio-demographics also a contributing factor. 

The paper outlined that learning to swim is just one part of water competency. To prevent drowning, Denny et al. recommended that people need broader water competencies including knowledge of local hazards, understanding of one’s limitations, ability to put on a life jacket, and all the first aid related to drowning (recognition, rescue, etc). Developing these skills takes time and developmental maturity. The paper highlighted some existing drowning prevention strategies such as the Haddon Matrix and ranks five major interventions as evidence-based: 4-sided pool fencing, life jackets, swim lessons, supervision, and lifeguards.

Denny et al. went on to identify the role of parents, medical providers, pool operators and policymakers in being informed of and promoting drowning prevention recommendations and legislation. The paper identified the most evidence-based interventions as being four-sided pool fencing, life jacket use, swim lessons, supervision and lifeguards and bystander CPR. 

The World Health Organizations “Drowning Prevention: an implementation guide” (2017) also formed much of the foundation for the prevention content. The paper provides practical steps to preventing drowning. 

Lifeline rescues

Pearn and Franklin (2009) carried out a study with 25 volunteers which tested their ability to throw a lifeline (rope) to a person simulating drowning 10 meters from the shore. The time and accuracy of achieving a successful lifeline throw were recorded for each of multiple attempts. The results indicated that more than half of fit adults cannot throw a lifeline accurately to a distance of ten meters even with multiple attempts and that, in the heat of the moment, one in five “rescuers” do not anchor the end of the rope, which is then lost when thrown. These results were compared to competitive or trained rescuers who can deploy a lifeline with extreme accuracy and great speed. 

The study highlighted the importance of the safety of the rescuer and the use of non-contact rescue to maintain this. However, it emphasised that to be successful in non-contact rescues, people need training and practise in throwing a lifeline or buoy. Pearn and Franklin implied that a person’s first time throwing a lifeline should not be in the midst of a life-threatening event. 

Water competencies

Stallman et al. (2017) built on previous work on water competencies to use evidence to select essential water competencies. They argue swimming skills alone are not enough to address drowning prevention. Rather a broad range of competencies are required including:

1. Safe water entry competence
2.  Breath control competence
3. Stationary surface competence (buoyancy or treading water)
4. Water orientation competence
5. Propulsion competence (swimming)
6. Underwater competence
7. Safe exit competence
8. Personal flotation device
9. Clothed water competence
10. Open water competence
11. Knowledge of local hazards competence
12. Coping with risk competence (awareness, assessment, avoidance)
13. Assess personal competence
14. Rescue competence (recognise and assist safely)
15. Water safety competence (attitudes and values)

Water context

See Water context for more scientific foundation.

Systematic reviews

Pascual-Gomez, L. M.,  Petrass, L. (2020). Recognition of drowning by layperson. Unpublished manuscript.

Beale-Tawfeeq, A. K. (2019). Triennial Scientific Review: Assisting Drowning Victims: Effective Water Rescue Equipment for Lay-responders. International Journal of Aquatic Research and Education, 10(4), 8.  Retrieved from https://scholarworks.bgsu.edu/cgi/viewcontent.cgi?article=1517&context=ijare 

Bierens, J., Abelairas-Gomez, C., Barcala Furelos, R., Beerman, S., Claesson, A., Dunne, C., Elsenga, H.E., … & Perkins, G.D. (2021). Resuscitation and emergency care in drowning: A scoping review, Resuscitation, DOI https://doi.org/10.1016/j.resuscitation.2021.01.033 

Olasveengen, T. M., Mancini, M. E., Perkins, G. D., Avis, S., Brooks, S., Castrén, M., … & Hatanaka, T. (2020). Adult basic life support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Circulation, 142(16_suppl_1), S41-S91. DOI https://doi.org/10.1161/CIR.0000000000000892 

Non-systematic review

Barcala-Furelos, R., Graham, D., Abelairas-Gómez, C., & Rodríguez-Núñez, A. (2021). Lay-rescuers in drowning incidents: A scoping review. The American Journal of Emergency Medicine. DOI https://doi.org/10.1016/j.ajem.2021.01.069

Franklin, R. C., & Pearn, J. H. (2011). Drowning for love: the aquatic victim‐instead‐of‐rescuer syndrome: drowning fatalities involving those attempting to rescue a child. Journal of paediatrics and child health, 47(1‐2), 44-47. DOI https://doi.org/10.1111/j.1440-1754.2010.01889 

Golden, F. S., Tipton, M. J., & Scott, R. C. (1997). Immersion, near-drowning and drowning. British Journal of Anaesthesia, 79(2), 214-225. DOI https://doi.org/10.1093/BJA%2F79.2.214 

International Life Saving Federation (2016). Medical position statement-MPS 21. Spinal injury management. Leuven, Belgium.  Retrieved from https://www.ilsf.org/wp-content/uploads/2018/11/MPS-21-2016-Spinal-Injury-Management.pdf

International Life Saving Federation (2016). Medical position statement–MPS 01. Abdominal thrusts. The use of abdominal thrusts in near drowning. Leuven, Belgium. Retrieved from https://www.ilsf.org/wp-content/uploads/2018/11/MPS-01-2016-Abdominal-Thrust.pdf 

Stallman, R.K., Moran, K., Quan, L., & Langendorfer, S. (2017). From swimming skill to water competence: Towards a more inclusive drowning prevention future. International Journal of Aquatic Research and Education: 10 (2) Article 3. DOI https://doi.org/10.25035/ijare.10.02.03 

Szpilman, D., Webber, J., Quan, L., Bierens, J., Morizot-Leite, L., Langendorfer, S.J., Beerman, S., Løfgren, B. (2014). Creating a drowning chain of survival. Resuscitation, 85(9), 1149-1152. DOI https://doi.org/10.1016/j.resuscitation.2014.05.034 

Szpilman, D., Bierens, J. J., Handley, A. J., & Orlowski, J. P. (2012). Drowning. New England journal of medicine, 366(22), 2102-2110. DOI 10.1056/NEJMRA1013317  

World Health Organization (2017). Preventing drowning: an implementation guide. Geneva, Licence: CC BY-NC-SA 3.0 IGO. Retrieved from https://www.who.int/publications/i/item/preventing-drowning-an-implementation-guide 

World Health Organization (2020). Drowning. September 9, 2020. Retrieved from https://www.who.int/news-room/fact-sheets/detail/drowning

 

Education references

Denny, S. A., Quan, L., Gilchrist, J., McCallin, T., Shenoi, R., Yusuf, S., … & Weiss, J. (2019). Prevention of drowning. Pediatrics, 143(5).  Retrieved from https://pediatrics.aappublications.org/content/143/5/e20190850

Pearn, J. H., & Franklin, R. C. (2009). “Flinging the squaler” lifeline rescues for drowning prevention. International Journal of Aquatic Research and Education, 3(3), 9. Retrieved from https://scholarworks.bgsu.edu/cgi/viewcontent.cgi?article=1262&context=ijare