Drowning

David Szpilman

Anthony J. Handley

Joost Bierens

Linda Quan

Rafael Vasconcellos

Drowning is an injury whose treatment may involve many layers of personnel from laypersons, lifeguards, and prehospital care providers to highly specialized hospital staff. Care of the drowning victim is unique in that bystanders or rescuers need specific skills that allow them to help the victim without becoming victims themselves. However, prevention, not resuscitation, is the primary objective with regard to drowning and adequate supervision of children is the most important preventative goal.

Updated definition- Drowning is progressive respiratory impairment from submersion in a liquid
The majority of drownings while accidental are due to negligence and failure of supervision
The most effective intervention for drowning is prevention
Additional medications may include antihistamines, corticosteroids, and glucagon.
Use a drowning algorithm for triage, treatment and prognosis

Introduction

On a sunny weekend day, a family was invited to a barbecue at a friend´s swimming pool. Suddenly, the mother noticed that her 4-year-old boy was missing. After about 7 minutes, he was found at the bottom of the pool and brought up to the pool’s edge. He appeared dead and no one knew what to do.

This scenario is usual in many countries and transforms a happy time into a very dramatic moment and a future for everyone involved not only of profound loss and grief but also guilt for failure to protect the victim or even intense anger at those who did not provide adequate supervision or medical care.

Drowning is an injury whose treatment may involve many layers of personnel, from laypersons, lifeguards, and prehospital care providers to highly specialized hospital staff. Care of the drowning victim is unique in that bystanders or rescuers need specific skills that allow them to help the victim without becoming victims themselves. Furthermore, the rescuers’ role is critical, since the chance for a good outcome rests almost entirely with care provided at the scene. If rescue and first aid from bystanders fail, delayed medical treatment cannot compensate for hypoxic injuries, even when more advanced therapies are initiated.

Interest in drowning rescue and resuscitation has existed for hundreds of years and drove the development of the first resuscitation instruments, research, protocols, education, and systems. In the past as well as today, drowning is among the most frequent causes of traumatic death. While the main focus of the current resuscitation community is on those with cardiac disease, this chapter advocates that the resuscitation of drowning victims should also be of importance to the resuscitation community, at least for those who are concerned with aquatic environments, which constitute 80% of the earth’s surface. Although drowning has often been a neglected public health problem,¹ it has recently begun to receive the attention it deserves.

At both the medical and societal levels, it must be recognized that every drowning-related death or hospitalization signals the failure of prevention.

Epidemiology

Each year, drowning is responsible for more than 500,000 deaths worldwide.² This number is an underestimate of the real figure. Especially in developing countries, many drowning deaths are unreported (Table 30-1).³ Statistics on drowning vary widely depending on different geographic, cultural, and economic resources. In some European countries, many drowning deaths are intentional injuries due to suicide, while in Australia, the United States, and Brazil, the majority of drowning deaths are unintentional. In the United States, an estimated 40% to 45% of drowning deaths occur during swimming.⁴ Mortality and, less frequently, hospitalization following drowning
are the most commonly reported indicators of drowning injury.

Table 30-1 • Global Coverage of Death Registration Data: WHO Presentation: “Mortality and Causes of Death”

	Developed Countries	Sub-Saharan Africa	Latin America	Middle East	Asia and Pacific	Total
Data available	55	4	29	9	18	115
Data not available	2	42	4	12	17	77
Total	57	46	33	21	35	192
Source: From International Life Saving Federation. World drowning report. Int J Aquatic Res Educ 2007;1:381–401, with permission.

Age, gender, alcohol use, socioeconomic status (income, education, and ethnicity), exposure, risk behavior, and lack of supervision are key risk factors in drowning. Considering all ages, males die five times more often from drowning than females. Young children, teenagers, and older adults are at highest risk of drowning. Worldwide, drowning is the leading cause of death in males between 5 and 14 years of age and the fifth leading cause among females.⁵ It is the leading killer of children 1 to 17 years of age in Asia.⁶

In the United States, drowning is the seventh leading cause of unintentional traumatic death for all ages and the second leading cause of all traumatic deaths among children 1 to 14 years of age.

Many of these injuries occur in recreational settings, including pools, spas/hot tubs, and natural outdoor settings (e.g., lakes, rivers, and oceans). During 2001 to 2002, an estimated 4,174 persons, on average, were treated in the United States emergency departments (EDs) for nonfatal, unintentional drowning injuries in recreational settings and 3,372 persons died of drowning in 2001. Children below the age of 4 years of age accounted for nearly 50% of such ED visits, and children aged 5 to 14 years accounted for an additional 25%. An estimated 75% of nonfatal injuries occurred in pools, whereas 70% of the fatalities occurred in natural outdoor settings. Approximately 53% of ED-treated patients required hospitalization or transfer to a hospital offering specialized care.⁸

In Brazil, with a population of 176 million inhabitants in 2003, a total of 6,688 died (3.8 per 100,000 inhabitants) by drowning, the second leading cause of death among those aged 1 to 14 years. Most of these drowning deaths, or 88%, were unintentional. Fatal drowning involved mostly 20- to 29-year-old individuals (22%), followed by those aged 15 to 19 (16%), 30 to 39 (15%), 10 to 14 (11%), 40 to 49 (9%), 1 to 4 (8%), and 5 to 9 (7%). There was no sex distinction in death rates under 1 year of age, but among those between the ages of 20 and 29, males drowned 8.7 times more often.⁹

As one of the largest year-round aquatic recreational areas in the world, Brazil provides a model for the development of a first-responder system for drowning, to be compared with emergency medical services (EMS) systems in other countries. In 1984, the emphasis on lifesaving increased significantly when firefighters assumed the role of lifeguarding the beaches and inland water spots, with many more professionals also on duty. The development of a large cadre of these professionals guarding the beaches led to the creation, in 1995, of the Brazilian Lifesaving Society, supported by the International Lifesaving Federation (ILS)—the largest world water safety organization. A recent study analyzed the drowning trends from 1979 to 2003 in Brazil.¹⁰ The effect of this initiative was a 30% reduction in rates of drowning death from 1979 (5.42 per 100,000) to 2003 (3.78 per 100,000). Most of this occurred from 1995 (4.91 per 100,000) to 2003 (3.78 per 100,000), suggesting that two interventions associated with maturation of the system—more lifeguards on duty and prevention campaigns—led to the dramatic decrease in drowning deaths (Fig. 30-1).

On Rio de Janeiro’s beaches, predisposing conditions are discernible in 13% of all drowning cases; the most common is use of alcohol (37%); followed by convulsions (18%); trauma, including boating accidents (16.3%); cardiopulmonary diseases (14.1%); skin and SCUBA diving (3.7%); diving resulting in head or spinal cord injuries; and others (e.g., homicide, suicide, syncope, cramps, or immersion syndrome: 11.6%).¹¹

These statistics highlight the fact that 87% of drownings occur with no reasons other than negligence by adults, regarding either themselves or their children.

Drowning: Definition and Terminology

The definition of drowning has been a significant problem for a long time. Until recently there has been no consensus either in the literature, among the various water safety and health organizations, among experts in the field, or among laypersons.¹² Terms and definitions were awkward and confusing, including sudden death, hypothermia, and diseases occurring in water. At the same time, some definitions excluded true cases of drowning due to complications of drowning, such as pneumonia, acute respiratory distress syndrome (ARDS), or ischemic encephalopathy. Therefore, the global scope of drowning has been wrongly measured not only through imprecise national statistics, but also through inadequate terms and definitions.

Figure 30-1 • Drowning death trends in Brazil from 1979 to 2003, selecting three different periods. (From Szpilman D, Goulart PM, Mocellin O, et al. 12 years of Brazilian Lifesaving Society (Sobrasa) – Did we make any difference? World Water Safety, Matosinhos- Portugal 2007.

Based on this problem, a Task Force on Epidemiology of Drowning (TFED) was established in 1998 within the framework of the World Congress on Drowning (WCOD). Following a discussion over several years, with contributions from many experts around the world, the TFED in 2002 adopted the following definition:

Drowning is the process of experiencing respiratory impairment from submersion or immersion in liquid.

According to this new definition, the drowning process is a continuum beginning with respiratory impairment—for example, when the patient’s airway is below the surface of the liquid or when there is a splashing of waves in the face. A patient can be rescued at any time during the process and given appropriate resuscitative measures, in which case the process of drowning is interrupted. Any submersion or immersion incident without evidence of liquid aspiration or respiratory impairment should be considered a water rescue and not a drowning. The terms “near-drowning,” “dry drowning,” “secondary drowning,” and “delayed onset of respiratory distress” are eliminated. Immersion or submersion is a way of drowning and not the name of a disease. ¹³

Pathophysiology of Drowning

Drowning may occur in fresh or salt water. A 2-year-old toddler may fall into a swimming pool, where he will disappear without any sign of distress, or a young, athletic swimmer may be caught by a rip current and, after an exhausting struggle, finally succumb. Despite some differences between drowning in fresh versus salt water, from a clinical and therapeutic perspective, there are no important differences in humans. The common significant pathophysiologic mechanism in any case of drowning is hypoxia.¹⁴

Despite some differences between drowning in fresh water versus salt water, from a clinical and therapeutic perspective, there are no important differences in humans.

Process of Drowning

Initially the victim is typically in an upright posture, with eyes just above the water surface, arms extended laterally, and thrashing and slapping on the water surface in an effort to get her airway above the water. Exhaustion will render the victim unable to scream for help. Children who cannot swim struggle for only 10 to 20 seconds before final submersion, while adults may be able to struggle for up to 60 seconds. When there is no way of keeping the airway out of the water, intentional breath-holding is the first automatic response. Water in the mouth is spit out or swallowed. When, after some time, a breath is taken, the result may be a first involuntary aspiration of water and consequent coughing or rarely laryngospasm, leading to hypoxia. If laryngospasm occurs, the onset of hypoxia will terminate it rapidly. If not, water is gradually but quickly aspirated into the lungs, rendering them unable to absorb oxygen. Consciousness deteriorates and is eventually lost.
Progressive hypoxia leads to apnea, followed by cardiac arrest. In the early stages of drowning, while the victim is still able to inhale some air, hyperventilation may lead to apnea and loss of consciousness as a result of a very low carbon dioxide level. The more intense the hyperventilation, the longer the apnea will persist. The victim may then stop struggling and slip below the water. This entire course of events may last from 1 minute to as long as hours.

Since the term “drowning” refers to a continuum that may or may not be fatal, a victim can be rescued at any time during the drowning process. The victim may not require any intervention at all or may receive appropriate resuscitative measures, in which case the drowning process is interrupted. Permanent brain damage generally occurs only in cases of cardiac arrest. The development of posthypoxic encephalopathy with or without cerebral edema is the most common sequela of cardiac arrest in resuscitated drowning victims. However, all organ systems can be involved in the postdrowning period, with complications including disseminated intravascular coagulation (DIC), acute tubular necrosis (ATN), and ARDS.

Physiologic Consequences of Drowning

The pulmonary damage of drowning is a function not of the water composition but of the pulmonary response to the water aspirated.

The aspiration of either fresh or salt water can produce, depending on the amount, surfactant destruction, alveolitis, and noncardiogenic pulmonary edema, resulting in an increased intrapulmonary shunting and hypoxia.¹⁵ In animal research, the aspiration of 2.2 mL/kg of water decreases the arterial oxygen pressure (PaO₂) to approximately 60 mm Hg within 3 minutes.¹⁶ In humans, aspiration of as little as 1 to 3 mL/kg of water produces profound alterations in pulmonary gas exchange and decreases pulmonary compliance by 10% to 40%.¹⁵ Humans rarely aspirate sufficient water to provoke significant electrolyte disturbances and victims usually do not require initial correction of electrolytes.¹⁷

Decreased cardiac output, arterial hypotension, increased pulmonary arterial pressure, and pulmonary vascular resistance are the results of hypoxia. Ventricular fibrillation (VF) in drowning is not common. When it occurs, the victim is usually older, with a history of coronary artery disease. VF is due to hypoxia and acidosis and not to hemolysis and hyperkalemia. VF may also occur during resuscitation, mainly owing to the use of epinephrine.

The more common scenario is hypoxia producing a well-established sequence of cardiac deterioration, with tachycardia followed by bradycardia, pulseless electrical activity (PEA), and finally asystole.¹⁵

Drowning Chain of Survival (Fig. 30-2)

Prevention

Despite the emphasis on immediate treatment, the most effective intervention for drowning is prevention.

Prevention programs are estimated to be potentially effective in preventing >85% of current annual drownings.²⁰^,²¹ Drowning prevention is multifaceted and involves education, technology, and legislation. In high-income countries, children below the age of 5 years have the highest drowning rates; they drown in swimming pools into which they fall while being unsupervised. The most effective intervention to prevent drowning in this age group is to fence in all swimming pools with four-sided, inclimbable fences with self-closing, self-latching gates. Legislation requiring installation of such barriers has been adopted in several countries.
However, enforcement of these laws is key to maximizing their effectiveness. Adequate supervision of children is the most important preventative goal. Supervision must be defined as the complete attention of an adult who is unimpaired by alcohol, drugs, or distraction and is capable of rescue.

Figure 30-2 • Drowning chain of survival. (From Szpilman D, Morizot-Leite L, Vries W, et al. First aid courses for the aquatic environment. In Bierens J, ed. Handbook on Drowning: Prevention, Rescue, and Treatment. Berlin: Springer-Verlag, 2005, with permission.)

Prevention of drowning in open water is more problematic, as it involves older children and adults engaged in a wide variety of activities. The prevention of such drowning has received less attention, since its victims usually die without medical interface. In the United States and Canada, >85% to 90% of boat-related drowning deaths involve people without life jackets. Some countries have legislation requiring children to wear life jackets while on small boats. However, adult males in small boats are the most common victims, and they are generally not required to wear life jackets.

Swimming or water survival skills may also enable potential victims to avoid drowning. Recent efforts in low-income countries to teach school-age children to dog paddle for a few yards has been helpful. Another subpopulation at risk of drowning comprises those who are subject to seizures. Most such drownings occur in the bathtub or during recreational swimming. Prevention for this group would be to shower instead of using the tub and to swim where there is a lifeguard. (See preventive measures in Table 30-2.)²²

Alarming (Recognition and Activation of Emergency Medical Services)

Contrary to popular opinion, the victim generally does not wave or call for help and usually drowns unnoticed. Bystanders may not recognize that the victim is struggling and may assume that the victim is playing and splashing in the water.

The key initial step in the treatment of drowning is to recognize that someone is drowning. Contrary to popular opinion, the victim generally does not wave or call for help and usually
drowns unnoticed.²³ A typical victim who drowns while swimming is a male young adult who may initially be embarrassed to cry for help and whose decision to ask for help is made too late, when his arms and legs are exhausted. While drowning, the victim is typically in an upright posture, with eyes just above the water surface, arms extended laterally, and thrashing and slapping on the water surface in an effort to get his airway above the water. Exhaustion will lead to the inability to scream for help. Bystanders may not recognize that the victim is struggling and may assume that he is playing and splashing in the water. The victim may submerge and surface several times during this struggle. Children who cannot swim struggle for only 10 to 20 seconds before final submersion, while adults may be able to struggle for up to 60 seconds.²³

Table 30-2 • Drowning Preventive Measures

Watch children carefully; 84% of child drownings occur because of poor adult supervision. Begin swimming lessons from 2 years old but be very careful at this age. Avoid inflatable swimming aids such as “floaties.” They can give a false sense of security. Use a lifejacket! Never try to help rescue someone without knowing how to do it. Many people have died trying to do so. Avoid drinking alcohol and eating before swimming. Do not dive into shallow water; this can lead to spinal injury.
Beaches	Pools, Spas, and Hot Tubs
Always swim in a lifeguard-supervised area. Ask the lifeguard for safe places to swim or play. Read and follow warning signs posted on the beach. Do not overestimate your swimming ability; 45% of drowning victims thought they knew how to swim. Swim away from piers, rocks, and stakes. Take lost children to the nearest lifeguard tower. Over 80% of drownings occur in rip currents (the rip is usually the most falsely calm deep place between two sandbars). If caught in a rip, swim transversally to the sand bar or let it take you away without fighting and wave for help. If you are fishing on rocks, be cautious about waves that may sweep you into the ocean. Keep away from marine animals.	Over 65% of deaths occur in fresh water, even on the coast. Fence off your pool and include a gate. Recommended approved fencing can decrease drowning by 50% to 70%. Avoid toys around the pool; they are very attractive to children. Whenever infants or toddlers are in or around water, be within arm’s length, providing “touch supervision.” Turn off motor filters when using the pool. Always use portable phones in pool areas, so that you are not called away to answer. Do not try to increase your submersion time by hyperventilating. Use warning signs of deep water in the pool. Learn CPR. Over 42% of pools owners are not knowledgeable about first aid techniques. Be careful!
Source: From Szpilman D, Orlowski JP, Bierens J. Drowning. In Fink M, Abraham E, Vincent JL, Kochanek P, eds. Textbook of Critical Care, 5th ed. Philadelphia: Elsevier Science, 2004:699–706, with permission.

In swimming pools, the victim usually goes unnoticed until he or she is observed to be under the water. This can happen in spite of good surveillance by pool lifeguards. The most effective method of pool surveillance still remains unclear and is currently under scientific investigation. Legally compulsory fencing and drowning detection systems can help to reduce the number of pool drownings.

The moment a drowning is recognized, it is essential to activate the emergency system to dispatch lifeguards and prehospital medical personnel to the scene and to take immediate action.

Rescue and Basic Water Life Support (BWLS)

Rescuers should be careful to not become additional victims.

Rescuers should be careful to not become additional victims. If possible, potential rescuers should stay out of the water and use techniques like “throw before you go” and “reach with a long object before you assist.” The rescuer can advise the victim on how to get out of the situation (i.e., choosing a better path of escape or reassuring the victim that assistance is coming).

The decision of how to provide BWLS¹⁸

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