AED First vs CPR First in Cardiac Arrest following Drowning BLS 856

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This CoSTR is a draft version prepared by ILCOR, with the purpose to allow the public to comment and is labeled “Draft for Public Comment". The comments will be considered by ILCOR. The next version will be labelled “draft" to comply with copyright rules of journals. The final COSTR will be published on this website once a summary article has been published in a scientific Journal and labeled as “final”.

Conflict of Interest Declaration

The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy.

The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: none applicable

The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: none applicable

CoSTR Citation

Beerman S, Mecrow T, Fukuda T, Bierens J, Olasveengen T, Bray J, Morley PT, Perkins GD. on behalf of the International Liaison Committee on Resuscitation BLS Life Support Task Force(s).

AED first vs CPR first for drowning, Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, <<INSERT DATE>>. Available from:

Methodological Preamble

The 2020 ILCOR CoSTR for CPR prior to defibrillation (BLS) Systematic Review recommendations for adult BLS suggested commencing CPR with compressions prior to defibrillation, weak recommendation, very-low-certainty evidence)”. (Graesner JT et al, 2020)

The 2020 ILCOR CoSTR Scoping Review on AED use in cardiac arrest due to drowning stated that AED use in cardiac arrest due to drowning appears feasible and safe in the aquatic environment. The chances of a shockable rhythm may be lower (2-14%) than for a primary cardiac cause. This may be particularly important where the cardiac arrest was caused by drowning. [ILCOR CoSTR 2020 BLS]

Shockable rhythms in cardiac arrest following drowning may have been caused by the progressive hypoxia of the drowning process, additionally cardiac arrests associated with drowning may have been caused by preceding or concurrent cardiac pathology. Whether a different approach in the special circumstances of cardiac arrest following drowning warrants an alternative approach, is uncertain.

This review was initiated following a request from the ILCOR BLS Task Force as part of a series of reviews relating to drowning.

The continuous evidence evaluation process for this Consensus on Science with Treatment Recommendations (CoSTR) started with a scoping review of the literature [Bierens 2021 205]. Following completion of the scoping review the decision was taken to progress to a systematic review. The systematic review was registered with PROSPERO CRD42021259983. The PICO question was developed by a group of drowning experts and approved by the ILCOR BLS Task Force. The search strategy was developed and run by Samantha Johnson. The results of the search strategy were reviewed and development of this CoSTR was conducted by Stephen Beerman, Thomas Mecrow and Tatsuma Fukuda in collaboration with Joost Bierens and Gavin Perkins. The CoSTR was reviewed and agreed by Basic Life Support and Paediatric Task Forces.



Adults and children in cardiac arrest1 following drowning2


AED administered before CPR in cardiac arrest following drowning


CPR administered before AED in cardiac arrest following drowning


Critical 9: Survival to discharge / 30 days or later

Critical 8: Survival with favourable neurological outcome to discharge / 30 days or later

Critical 7: Return of spontaneous circulation (ROSC)

Study Design

Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) are eligible for inclusion.

Unpublished studies (e.g., conference abstracts, trial protocols), manikin studies, narrative reviews and animal studies were excluded.

All years and all languages are included as long as there is an English abstract


Database inception to current time.

1A broad definition of cardiac arrest will be used including those who are unconscious and not breathing normally or those requiring resuscitation interventions e.g. chest compressions, defibrillation.

2 Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid

PROSPERO Registration CRD42021259983

Consensus on Science

A search of Medline, Pre-Medline, Embase, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials identified 195 references. After review of titles and abstracts 34 papers were shortlisted for full text review, 6 additional studies were identified for full text review following citation searching. No studies were identified which addressed the PICOST question.

Treatment Recommendations

When available, we recommend an AED is used in cardiac arrest following drowning in adults and children. CPR should be started first and continued until an AED has been obtained and is ready for use (Good practice statement).

Justification and Evidence to Decision Framework Highlights

Drowning is the third leading cause of unintentional injury related deaths around the world. Improving successful resuscitation with reduced morbidity would be a lifesaving and life improving outcome. Developing evidence-based treatment recommendations to aid those attempting to resuscitate people following drowning is therefore a high priority and high value if improved outcomes can be achieved.

No direct evidence related to AED first vs CPR first following drowning was found, the review team noted:

  • Shockable rhythms may be rare in cardiac arrest following drowning (2 – 14%) but slightly higher in children and witnessed events. (Bierens 2021 204, Dyson 2013 1114, Dennis 2018 1477, Nitta 2013 1568, Grmec 2009 7, Claessen 2008 381)
  • Cardiac arrest following drowning is most commonly caused by the hypoxic drowning process. (Kirohara 2017 14),
  • Cardiac arrest following drowning may be a primary cardiac event in adults and children. (Kirohara 2017, 14)
  • There is conflicting data about improved outcomes when shockable rhythms are present. (Tobin 2017 39, Buick 2014 214)
  • More research is needed in cardiac arrest following drowning in adults and children.

The review group considered the current availability and acceptability of AED in high income countries and the lack of availability of AED in Low- and Middle-Income Countries (LMICs). The desire for improved outcomes in cardiac arrest following drowning is strong in all settings. The incremental outcome improvement when AED is added to CPR following drowning, is small at best. The group considered it unlikely that the addition of AED has a large negative effect when the equipment, training and maintenance functions are available. AED can be applied safely by trained persons, in cardiac arrest following drowning.

Adding AED to the cardiac arrest resuscitation after drowning algorithm, increases equipment, training, and maintenance of function costs. The addition of AED to the resuscitation algorithm increases global health inequity. At present, it is not feasible to implement AED in LMICs where the great majority of global drowning occurs.

AEDs have been used widely in people who have drowned. The review did not find evidence of harm from deployment of AEDs in this setting. Most aquatic rescue guidelines highlight the importance of drying the chest and ensuring the victim is not in water at the time of attempted defibrillation.

Rationale for Treatment Recommendations

195 abstracts were reviewed, of which 34 proceeded for a full text read. 6 papers were included and 4 were added because they were cited by the full text review and informed this PICOST question. No studies were identified that had direct data comparing an AED first vs CPR first resuscitation strategy for cardiac arrests due to drowning.

To inform a good practice recommendation, the reviewers identified literature which indirectly related to the research question. The rationale for a CPR first strategy is due to the hypoxic mechanism of cardiac arrest following drowning. Early CPR will reverse the hypoxia and prevent the patient from progressing from respiratory arrest to cardiac arrest or increase the likelihood of return of spontaneous circulation (ROSC).

The 2021 ILCOR Scoping Review on AED first stated that only a small proportion of cardiac arrest following drowning cases (2%-14%) present with a VF/VT shockable rhythm. This may be due to duration of submersion, longer response and recovery times often associated with drowning cases. (1) The scoping review stated that “there is also no evidence to suggest that drowning cases presenting with a shockable rhythm are associated with increased survival outcomes”

In this Systematic Review we did find evidence that shows improved outcomes with an initial shockable rhythm. Dyson et al. (8) reviewed 336 drowning-related OHCA attended by EMS, during the study period. Few patients were found in a shockable rhythm (6%), with the majority presenting in asystole (79%) or pulse-less electrical activity (13%). An initial shockable rhythm was found to be positively associated with survival to hospital discharge (AOR 48.70, 95% CI: 3.80-624.86). (2)



  1. Bierens J, Abelairas-Gomez C, Barcala Furelos R, Beerman S, Claesson A, Dunne C, Elsenga HE, Morgan P, Mecrow T, Pereira JC, Scapigliati A, Seesink J, Schmidt A, Sempsrott J, Szpilman D, Warner DS, Webber J, Johnson S, Olasveengen T, Morley PT, Perkins GD.
  2. Resuscitation and emergency care in drowning: A scoping review. Resuscitation. 2021 May;162:205-217. doi: 10.1016/j.resuscitation.2021.01.033. Epub 2021 Feb 4. PMID: 33549689.
  3. *Dyson K, Morgans A, Bray J, Matthews B, Smith K. Drowning related out-of-hospital cardiac arrests: characteristics and outcomes. Resuscitation. 2013 Aug;84(8):1114-8. doi: 10.1016/j.resuscitation.2013.01.020. Epub 2013 Jan 29. PMID: 23370162.
  4. Dennis M, Elder A, Semsarian C, Orchard J, Brouwer I, Puranik R. A 10-year review of sudden death during sporting activities. Heart Rhythm. 2018 Oct;15(10):1477-1483. doi: 10.1016/j.hrthm.2018.04.019. Epub 2018 Apr 18. PMID: 29678777.
  5. Kiyohara K, Sado J, Matsuyama T, Nishiyama C, Kobayashi D, Kiguchi T, Hayashida S, Kitamura Y, Sobue T, Nakata K, Iwami T, Kitamura T.
  6. Out-of-hospital cardiac arrests during exercise among urban inhabitants in Japan: Insights from a population-based registry of Osaka City. Resuscitation. 2017 Aug;117:14-17. doi: 10.1016/j.resuscitation.2017.05.025. Epub 2017 May 25. PMID: 28552657.
  7. Mogayzel C, Quan L, Graves JR, Tiedeman D, Fahrenbruch C, Herndon P. Out-of-hospital ventricular fibrillation in children and adolescents: causes and outcomes. Ann Emerg Med. 1995 Apr;25(4):484-91. doi: 10.1016/s0196-0644(95)70263-6. PMID: 7710153.
  8. *Nitta M, Kitamura T, Iwami T, et al. Out-of-hospital cardiac arrest due to drowning among children and adults from the Utstein Osaka Project. Resuscitation. 2013;84(11):1568-1573. doi:10.1016/j.resuscitation.2013.0
  9. *Grmec S, Strnad M, Podgorsek D. Comparison of the characteristics and outcome among patients suffering from out-of-hospital primary cardiac arrest and drowning victims in cardiac arrest. Int J Emerg Med. 2009;2(1):7-12. doi:10.1007/s12245-009-0084-0
  10. *Claesson A, Svensson L, Silfverstolpe J, Herlitz J. Characteristics and outcome among patients suffering out-of-hospital cardiac arrest due to drowning. Resuscitation. 2008 Mar;76(3):381-7. doi: 10.1016/j.resuscitation.2007.09.003. Epub 2007 Nov 7. PMID: 17997210.
  11. Buick, J., Lin, S., Rac, V., Brooks, S., Kierzek, G., & Morrison, L. (2014).
  12. Drowning: An overlooked cause of out-of-hospital cardiac arrest in Canada. Canadian Journal of Emergency Medicine, 16(4), 314-321. doi:10.2310/8000.2013.131069
  13. Tobin JM, Ramos WD, Pu Y, Wernicki PG, Quan L, Rossano JW. Bystander CPR is associated with improved neurologically favourable survival in cardiac arrest following drowning. Resuscitation. 2017 Jun;115:39-43. doi: 10.1016/j.resuscitation.2017.04.004. Epub 2017 Apr 4. PMID: 28385639

*secondary literature search



John Mouw
(5 posts)
The comparators are AED for CPR first after drowning. The reviewers acknowledged that good practice recommendation is based on "The rationale for a CPR first strategy is due to the hypoxic mechanism of cardiac arrest" despite lack of conclusive evidence. Experience has taught us that people (Instructors and rescuers) when reading a recommendation tend to follow and teach in the order a recommendation is presented. Understanding the importance of both CPR and AED, I suggest reversing the order of the sentences in the recommendation to: "CPR should be started first and continued until an AED has been obtained and is ready for use. When available, we recommend an AED is used in cardiac arrest following drowning in adults and children."

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