Elsevier

Resuscitation

Volume 76, Issue 3, March 2008, Pages 381-387
Resuscitation

Clinical paper
Characteristics and outcome among patients suffering out-of-hospital cardiac arrest due to drowning

https://doi.org/10.1016/j.resuscitation.2007.09.003Get rights and content

Summary

Aim

To describe the characteristics and outcome among patients with out-of-hospital cardiac arrest (OHCA) caused by drowning as compared with OHCA caused by a cardiac etiology (outside home).

Patients and methods

All the patients included in the Swedish OHCA Registry between 1990 and 2005 which were not crew witnessed, in whom cardio-pulmonary resuscitation (CPR) was attempted, were evaluated for inclusion. Those caused by drowning were compared with those with a cardiac etiology (outside home).

Results

Patients with OHCA due to drowning (n = 255) differed from patients with OHCA with a cardiac etiology (n = 7494) as they were younger, less frequently suffered a witnessed OHCA, more frequently received bystander CPR and less frequently were found in a shockable rhythm. Patients with OHCA due to drowning had a prolonged ambulance response time as compared with patients with OHCA with a cardiac etiology. Patients with OHCA due to drowning had a survival rate to 1 month of 11.5% as compared with 8.8% among patients with OHCA due to a cardiac etiology (NS). Among patients with OHCA due to drowning, only one independent predictor of survival was defined, i.e. time from calling for an ambulance until the arrival of the rescue team, with a much higher survival among patients with a shorter ambulance response time.

Conclusion

Among patients with OHCA 0.9% were caused by drowning. They had a similar survival rate to 1 month as compared with OHCA outside home with a cardiac etiology. The factor associated with survival was the ambulance response time; a higher survival with a shorter response time.

Introduction

During the last century, the number of drownings in Sweden has decreased. According to the Swedish lifesaving society—SLS, around 1000 persons or 19.2/100,000 inhabitants drowned in Sweden in the late 1800s. An average over the last 10 years 1997–2006, show 1.2/100,000 drownings per year.1 The number of drownings are even higher when intentional, homicidal and unclear cases are added as in the National board of health and welfares register over causes of death, which are based upon the ICD10 code system. In 2003 they reported 246 drownings or 2.74/100,000 inhabitants, of these were 25% intentional drownings.2 There also appears to be an increase in drownings during summers with higher water temperatures and more recreational activities. The aquatic environments are more frequently visited today than they were 100 years ago, however the relationship between swimming ability and drowning risk is still pretty much unknown.3 A patient with cardiac arrest caused by drowning presents with a specific problem. It is often difficult to reconstruct the course of the event and the initial intent of the victim, as some drownings are intentional. Drowning also often occurs in rural settings, such as lakes, ponds or streams, with an expected prolonged ambulance response time.

The aim of this study is to describe the characteristics and survival of patients suffering out-of-hospital cardiac arrest (OHCA) caused by drowning. The results will be compared with the traditional out-of-hospital cardiac arrest, outside the home, where the arrest is judged to be caused by a cardiac etiology.

Section snippets

Patients

Patients suffering a cardiac arrest to whom an ambulance was called were included in the registry, with the exception of patients who had obviously been dead for a long time and whose bodies were therefore not taken to hospital by the ambulance crew. For the others, the standardised form was completed by the ambulance crew.

Registry

This study is based on material collected by the Swedish Cardiac Arrest Registry, which is a joint venture between the Federation of Leaders In Swedish Ambulance and

Results

In all, 40,503 patients who suffered an out-of-hospital cardiac arrest in whom CPR was started were evaluated for inclusion in this survey. Among them 4,770 were crew witnessed and therefore excluded. Among the remaining 35,733 patients information on the cause of cardiac arrest was missing in 2,790 patients (8%). Among the remaining 32,943 patients, the OHCA was judged to be caused by drowning in 299 patients (0.9%), while it was judged to be caused by a cardiac etiology outside home in 7494

Univariate analysis (Tables 1 and 2 and Figures 1 and 2)

As shown in Table 1, among patients with OHCA outside home survival to hospital admission was higher among patients with OHCA due to drowning as compared with OHCA due to cardiac etiology. However, survival to 1 month did not significantly differ between the two groups.

As shown in Table 2 and Figure 1 (all patients with OHCA due to drowning included), survival was associated with age, with higher survival among younger patients, and with ambulance response time. Survival was markedly higher

Overall results

The survival rate to 1 month among patients with OHCA outside home caused by drowning did not differ significantly from that among patients with OHCA caused by a cardiac etiology. Survival was most markedly associated with ambulance response time.

Although cardiac arrests caused by drowning are less frequently witnessed, bystanders are often willing to commence CPR in these cases particularly in the younger age groups.

Age

People of all ages come in contact with aquatic environments at one time or

Implications

Although survival among patients with OHCA due to drowning appeared to be relatively high, almost nine in every 10 patients did not survive to 1 month. Although we must aim to reduce the ambulance response time still further, there are practical obstacles to achieving this goal.

Although bystander CPR was not significantly associated with increased survival, the study was underpowered to address this question adequately. In all probability, bystander CPR will increase survival in this OHCA

Limitation

There was missing information in nearly all the variables that were evaluated.

Conclusion

Among patients suffering from OHCA in whom CPR was attempted and who were included in the Swedish Cardiac Arrest Registry, 0.9% of the OHCA were caused by drowning. These patients had a relatively high survival rate to 1 month (11.2%) which did not significantly differ from survival among patients with OHCA of a cardiac etiology outside home. The factor that was most strongly associated with survival was the ambulance response time and much higher survival was found among patients with a

Conflict of interest statement

There are no financial or other relations that might pose a conflict of interests.

References (25)

  • P.G. Schnitzer

    Prevention of unintentional childhood injuries

    Am Fam Physician

    (2006)
  • W.A. Harrell

    Lifeguards’ vigilance: effects of child-adult ratio and lifeguard positioning on scanning by lifeguards

    Psychol Rep

    (1999)
  • Cited by (65)

    View all citing articles on Scopus

    A Spanish translated version of the summary of this article appears as Appendix in the final online version at 10.1016/j.resuscitation.2007.09.003.

    View full text