Applied Evidence

Drowning episodes: Prevention and resuscitation tips

Author and Disclosure Information

CPR for drowning survivors differs from that commonly used in cardiogenic cardiac arrest. Routine antibiotic prophylaxis is not indicated.


 

References

PRACTICE RECOMMENDATIONS

› Recommend swimming lessons for all children ages 4 and older. C
› Consider antibiotics after a drowning event only if the water is known to be contaminated or the victim has aspirated a large volume of water. C
› Monitor asymptomatic patients for at least 4 hours after a drowning event. C

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series

A young mother in your practice wants her toddler to begin swimming lessons because her family loves water activities. How would you advise her? In fielding an urgent call about a drowning incident, what priorities would you urge regarding resuscitation at the scene? For a stabilized patient following a drowning episode, when might antibiotics be indicated? This article covers these issues as well as follow-up matters such as assisted ventilation and tiered hypothermia intervention.

Drowning likely occurs more often than is reported

Worldwide, drowning accounts for more than 388,000 deaths annually and is the third leading cause of unintentional injury death. Low- and middle-income countries represent 96% of the yearly total.1 As reported in the United States, nearly 6000 individuals are hospitalized and nearly 4000 die from drowning events annually.2 But these figures likely underestimate the true rate, as many drowning fatalities are officially attributed to floods, boating accidents, or other associated events. Nonfatal drownings often go unreported.

Children under the age of 5 years have the highest drowning mortality worldwide, and drowning is the leading cause of unintentional injury death for this age group in many countries, including the United States.1,2 Men are nearly 4 times as likely to die from drowning than women.2 Predictably, in the United States most drowning happens on the weekend and during summer months. More than half of drownings in children younger than 4 years occur in swimming pools; with increasing age, drowning is more likely to occur in natural bodies of water.2 With adults in higher income countries, alcohol is a significant contributor to drowning events during recreational activities.3-5

Much effort has been made in recent years to standardize the nomenclature and treatment of drowning episodes. The International World Congress on Drowning met in the Netherlands in 2002, and established the definition of drowning as “the process of experiencing respiratory impairment from submersion/immersion in liquid.”6 Submersion refers to the complete submergence of the victim under the water, while immersion implies that the victim’s airway remains above the water.

CPR should begin, if possible, the moment the victim is out of the water.The Congress recommended that terms such as “wet-drowning,” “dry-drowning,” and “near-drowning” be discontinued in favor of the outcome classifications “death,” “no morbidity,” and “morbidity.” The “morbidity” subgroup was further characterized as “moderately disabled,” “severely disabled,” “vegetative state/coma,” and “brain death.” This meeting established guidelines on the treatment of drowning victims in addition to outlining points for future research.6

Physiologic chain of events in drowning

An unexpected immersion in water, particularly cold water, causes a reflexive inspiratory gasp, and some degree of aspiration occurs in most, if not all, cases of drowning. Aspiration further impairs victims’ ability to hold their breath or breathe normally.5,7,8 It decreases lung compliance due to surfactant washout or intrapulmonary shunting and thereby leads to hypoxia. Aspiration-induced severe laryngospasm can also lead to hypoxia. Pulmonary edema and acute respiratory distress syndrome (ARDS) can follow.

The cardiovascular effects of drowning mirror those seen in hypoxia. Initially, apnea leads to decreased oxygen saturation and precipitates tachycardia and hypertension. Bradycardia and hypotension follow and blood is shunted to vital organs, such as the brain, heart, and lungs.9 This phenomenon is accelerated in cold water and leads to “swimming failure,” the impaired ability of the victim to swim because of decreased perfusion of the extremities.5,7,8,10

“Autonomic conflict” has been proposed as an additional mechanism for morbidity and mortality from drowning episodes. Breath holding and immersion in cold water each can induce cardiac arrhythmias. When combined, these events may increase the risk of an arrhythmogenic state secondary to opposing chronotropic effects: the diving reflex (bradycardia via parasympathetic activation), and the cold shock response (tachycardia via sympathetic activation). This is thought to be an underreported cause of death in drowning, as arrhythmias are undetectable during autopsy.8,11

Drowning prevention

The American Academy of Pediatrics (AAP) recommends swimming lessons for most children ages 4 years and older.12 Previously, swimming lessons were not recommended for children ages 1 to 4 because evidence of benefit was lacking, and there was some concern that it might reduce children’s caution around water and reduce parents’ perceived level of need for supervision. Although data are still conflicting, some reports have since shown benefit in early swimming lessons for
toddlers.13,14

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