Management of Drowning

Justin Sempsrott

INTRODUCTION

Water covers more than 70% of the earth and can be beautiful, fun, and life sustaining. But, for as long as there have been people, the hazards of water have caused morbidity and mortality. From backyard swimming pools to placid lakes, from the ocean to fast-moving rivers, water presents an opportunity for fun, beauty, or tragedy.

Definition

The term drowning has often been used to describe death from being underwater. There were numerous published definitions of drowning and ancillary terms such as “near,” “wet,” “dry,” “secondary,” or “delayed” drowning. These terms are poorly defined throughout the scientific literature and in common usage. As a medical, research, scientific, and lay community, we have long used these terms to try and explain those persons who drown and survive the initial incident. To provide clarity, a consensus definition was created in 2002 and subsequently accepted by the World Health Organization, the International Liaison Committee on Resuscitation, the Wilderness Medical Society, the Utstein Style system, the International Lifesaving Federation, the International Conference on Drowning, Starfish Aquatics Institute, the American Red Cross, the U.S. Centers for Disease Control and Prevention, the American Red Cross, and numerous other medical, first aid, and cardiopulmonary resuscitation (CPR) societies. All these groups specifically caution against the use of older terminology, such as “dry,” “secondary,” or “near” drowning, or their analogues.”¹^,²^,³^,⁴^,⁵^,⁶^,⁷^,⁸^,⁹ There are only three outcomes to the drowning process—death, survival with morbidity, and survival without morbidity. The emphasis of the new definition is to understand drowning as a process and not as an outcome.⁵

Every year, thousands of people in the United States survive heart attacks or stroke. Some of these survivors return to their normal activities of daily living and some require around the clock care from family or skilled nursing facilities. You would not refer to these survivors as having had a “near-stroke” or “near-heart attack”; in the same way, you should not refer to the survivor of a drowning incident as a “near-drowning.”¹⁰ It is possible to drown and survive with the outcome of death; with no morbidity; and with mild, moderate, or severe morbidity. The preferred terminology would be to refer to a drowning incident as fatal or non-fatal.

Scope of Discussion

Similar to cardiac arrest, there is a drowning chain of survival¹¹ (Figure 16.1).

Most simply, it is prevention, rescue, and treatment. As with most things in the outdoors, knowledge of the risks and hazards is the most important tool of prevention. Once prevention has failed, timely rescue and appropriate treatment are vital to reduce morbidity and prevent death. This chapter will cover the physiology, prevention, rescue, and treatment of drowning and its associated injuries. Rescue techniques and technical rescue are beyond the scope of this chapter. However, technical rescue in general is covered in Section Three of this book, with swiftwater rescue covered in Chapter 26 and open water rescue covered in Chapter 27.

EPIDEMIOLOGY

Drowning is common and often underreported. The discussion of its epidemiology is confusing and can be misleading. According to the 2014 World Health Organization Global report Drowning: Preventing a Leading Killer, it is the third leading cause of unintentional injury death with 372,000 drowning deaths per
year.¹² More than 90% of the world’s drowning deaths occur in low and middle income countries. Frequently, these deaths occur in settings where there are no formal emergency medical services (EMS) or hospitals, so data are lacking.¹³ The most conservative estimate is that for every drowning death that is reported, an additional five receive care in the emergency department (ED).¹⁴^,¹⁵^,¹⁶ Additionally, for every fatal drowning incident, there are four or more non-fatal drowning incidents.¹⁴^,¹⁵^,¹⁶ The 372,000 drowning deaths likely represent 1,860,000 deaths and an additional 7,444,000 non-fatal drowning incidents, though exact numbers are difficult to confirm. The outcome of the non-fatal drowning is not well studied and ranges from mild developmental delay to neurologic devastation and anoxic brain injury requiring around the clock care.¹⁷

FIGURE 16.1. Drowning chain of survival. From Szpilman D, Webber J, Quan L, et al. Creating a drowning chain of survival. Resuscitation. 2014;85(9):1149-1152.

To further complicate data collection, drowning deaths that occur as a result of boating, floods, or natural disasters are classified separately. The exact number of drowning deaths and non-fatal drowning incidents that occur during floods and natural disasters is difficult to obtain. In the United States, there are an average of 3,563 drowning deaths per year plus an additional 332 boating-related deaths.^*,^†

At the time of this writing, there is a massive humanitarian crisis of refugees fleeing the Middle East and Africa into Europe via North Africa and the Mediterranean Sea. By mid-November 1, 2016, there were 332,674 persons arriving in Europe by the sea route with 3,930 dead or missing. Though there were 1,015,078 arrivals by sea in 2015, there were only 3,771 dead or missing at sea, making 2016 far deadlier for those making the treacherous crossing. These deaths are not reported as “drowning” incidents and are often tabulated as aquatic transport accidents.

Worldwide, the highest risk group for drowning is 1- to 4-year-old children who wander into residential swimming pools or natural bodies of water during brief lapses in supervision, often from a nonparent caregiver. Drowning kills more children aged 1 to 4 than any cause other than birth defects.¹⁸ Another high risk group is teenaged or college aged recreational boaters without lifejackets. In 2015 alone, the United States Coast Guard recorded 626 fatal boating incidents, of which 85% were not wearing a life jacket.¹⁹ Across the spectrum of low, middle, and high income countries, males represent approximately 80% of drowning deaths. Drowning accounts for the highest number of fatalities at U.S. National Parks, even more than heat, cold, wildlife, vehicle, boat, bus, bike, and airplane collisions combined.²⁰

CLINICAL MANAGEMENT

Drowning patients can present with mild, moderate, or severe symptoms.²¹ The primary source of morbidity and mortality is anoxic brain injury, and the immediate treatment priority after rescue is providing oxygen to the brain.²²^,²³ If the person survives the initial incident, then further morbidity and deterioration are determined by the amount of anoxic brain injury. Drowning is a brain problem with lung complications.

Identification

The drowning process begins when the mouth and nose fall below the water, or are immersed from the action of waves, sea spray, swiftwater, or other such means. During the initial struggle, there is breath holding. Very little, if any, water enters the lungs during the struggle, and the amount that does enter is typically less than 30 mL.²¹

The published medical literature and anecdotal experience show that time to unconsciousness and pulselessness in drowning patients is varied based on the person’s age, comorbidities, underlying physical conditioning, and physiologic state.²⁴^,²⁵
In operating room studies of normal, healthy, adults, the time to unsafe apnea, with resultant loss of consciousness, is 1 minute, as compared to 8 minutes if they receive high flow oxygenation prior to induction of paralysis. From the same studies, an obese (127 kg) adult would only have 162 seconds of safe apnea after prolonged preoxygenation and a 10-kg child only 200 seconds.²⁴^,²⁵ This time is expected to be significantly shortened in a drowning person who obviously did not receive preoxygenation. Thus, many drowning persons will lose consciousness within seconds or 1 to 2 minutes.

Before losing consciousness, there may or may not be additional aspiration of water. This was previously attributed to laryngospasm, which is much more rare than previously described and in reality occurs in only 3% to 5% of drowning patients.²¹ In the first few minutes after losing consciousness, the person will still have protective airway reflexes. As water enters the mouth, oropharynx, and upper airways, it may be spat out or reflexively swallowed, which prevents water from entering the lungs. Autopsy studies of known drowning patients show that only 1 to 2 mL/kg body weight actually enters the lungs.²⁶ It is thought that some of the water may also be absorbed across the alveolar membrane. Conversely, these same patients may have no water or several liters of water in the stomach.²⁶ Drowning is not necessarily a problem of the lungs filling with water.²⁷ While the person is underwater, the blood becomes progressively more hypoxemic and acidemic. The brain is the most sensitive organ to hypoxemia and may begin to suffer irreversible damage within minutes.²¹^,²⁶ Drowning is a brain problem with lung complications. Reversing the cerebral hypoxia is the primary goal of emergent treatment.

The small volumes of water that enter the lungs can still complicate efforts at initial oxygenation and ventilation. Regardless of salinity, the water damages pneumocytes resulting in atelectasis and impaired gas exchange at the alveolar level.²¹^,²⁶

The aspirated water also mixes with the pulmonary surfactant, causing atelectasis and creating potentially large volumes of non-cardiogenic pulmonary edema (foam). Pediatric patients, the elderly, and persons with medical comorbidities are the most sensitive to decompensation from an initially minor drowning incident. In the absence of an anoxic brain injury, the amount of water aspirated determines the severity of initial injury. For patients who survive the initial incident without cerebral hypoxia, long-term pulmonary morbidity has not been described in the literature, and the lungs tend to heal themselves over the next 24 to 48 hours.²¹^,²⁶^,²⁸

Table 16.1 Classification of Drowning Patients

	Signs/Symptoms	Mortality (%)	Treatment
Grade 1	Cough, no foam at mouth/nose	0	Thorough history—Release home with education
Grade 2	Small amount foam in mouth or nose, +Rales	0.6	N/C O₂—Hospital
Grade 3	Large amount foam, normal BP (radial pulse present)	5.2	ETT/NRB O₂—Hospital
Grade 4	Large amount foam, low BP (radial pulse absent)	19.4	ETT/NRB O₂, IV Fluids—Hospital
Grade 5	Respiratory arrest	44	ETT/NRB O₂, IV Fluids—Hospital
Grade 6	Cardiopulmonary arrest	93	ETT/NRB O₂, IV Fluids, AED—Hospital Do not resuscitate if down >1 h
From Szpilman D. Near-drowning and drowning classification: a proposal to stratify mortality based on the analysis of 1,831 cases. Chest. 1997;112(3):660-665.

The largest case series to date on drowning patients describes the rescue and treatment of nearly 42,000 patients rescued by ocean lifeguards in Brazil.²⁹ In the model proposed by this case series, drowning patients may present with mild, moderate, or severe symptoms (Table 16.1).

The Minimally Symptomatic Grade: Grade 0 to 1

These patients may have been underwater for only a brief time, or have had their face intermittently immersed from waves, whitewater, sea spray, etc. Their symptoms are limited to a mild cough and no foam present at the mouth or nose. There is typically no aspirated water in the lower airways and they are able to clear the upper airways by coughing alone. Based on the largest case series to date, mortality is 0%.

The Moderately Symptomatic Grade: Grade 2 to 3

These patients will present with small or large amounts of foam from the mouth or nose. They may be conscious and coughing or, due to decreased oxygen delivery to the brain, their mental status may range from confused to combative to unconscious. Whether the patient is an adult struggling in whitewater or a child sinking silently to the bottom of a pond, they are releasing large amounts of epinephrine and endogenous catecholamines to keep the hypoxic heart beating. Upon rescue, they will likely be completely exhausted and seemingly unresponsive despite being conscious. Grade 2 and 3 drowning patients will often have reversible degrees of cerebral hypoxia and respond well to oxygenation and interruption of the drowning process. Mortality in this group is 0.5% to 5%.

These patients have previously been mislabeled as “dry,” “secondary,” “delayed,” “near,” or “parking lot” drownings. There is no accepted medical definition of these terms and all major accrediting bodies actively discourage their use. Because the
term “drowning” is often used to mean death, we often are at a loss for a way to describe the patients who are initially symptomatic and later survive. These cases are frequently described in the media as children or adolescents who “drown on dry land” or “drown in their sleep,” which can be frightening to medical professionals and the lay public. In reality, these patients show symptoms as soon as they come out of the water. There are no published case reports of a completely asymptomatic patient later developing symptoms. With a mortality of 0.5% to 5%, all symptomatic patients require evaluation in an ED and are monitored for the development of symptoms over the next 4 to 8 hours. Disposition is discussed in detail below.

The Severely Symptomatic Patient: Grade 4 to 6

Progressive hypoxemia eventually leads to hypotension followed by respiratory and then cardiac arrest. There is often a large amount of foam in the mouth and nose, cold, clammy, cyanotic skin, and rapid heart rate. Grade 4 to 6 patients are unconscious and in need of immediate resuscitation to interrupt the drowning process. Mortality in this group ranges from 20% to 93%.

Prevention

As with most injuries, prevention has a far greater ability to save lives and prevent tragedy than rescue and treatment. Prevention can be categorized according to the risk factors for specific age groups.

Drowning Prevention in Ages Younger than Six

Worldwide, and across income levels, this is the highest risk age group for drowning, and for many of the same reasons. Children at this age are mobile enough to fall into small and large bodies of water, from buckets to toilets to pools or ponds, without necessarily being able to right themselves or self-extricate. They are often unaware of the hazards and can be drawn to the shimmer of the water, pool toys, or other such objects without being aware of the danger. Throughout the developed world, water is typically restricted to recreational or utility areas. In developing nations and wilderness settings, water may be ubiquitous and is the source of sustenance for drinking, bathing, commerce, and transportation. Where there is water, there is always risk. It is impossible to make water safe, so we must strive to make it safer. There is no single “silver bullet” strategy and prevention requires layers of protection (Figure 16.2).

Maneuvers for injury prevention in this age group can be remembered by the familiar EMS mnemonic ABCD, repurposed here for drowning prevention.

A. Adults. Adult supervision must be constant and uninterrupted. The risk of drowning increases significantly when the child is being supervised by a non-primary adult (eg, babysitter, aunt, sibling, etc.) or by another child. Numerous cases involve brief lapses in supervision, with the caregiver often reporting “I only turned away for a moment.” A child will only struggle at the surface of the water for approximately 20 seconds before sinking, and the struggle is often silent. While around the water, “touch supervision” is recommended, with the child within arm’s length of the caregiver at all times. During outdoor or backyard events where there is a pool or natural water nearby, a lifeguard or “Water Watcher” (Figure 16.3) should be appointed. There are numerous variations of the water watcher program, but this should be a sober, responsible adult who watches the body of water, without interruption from eating, drinking, telephone, text messaging, or other distractions.

FIGURE 16.2. The ABCD’s of drowning prevention.

A whistle or water watcher tag often worn to denote responsibility is handed off to the next adult who assumes responsibility. Numerous fatal and non-fatal child drowning incidents have occurred with a large number of adults around the body of water, incorrectly assuming that someone else was watching the children.

B. Barriers. Pool fences with self-latching gates that cover the pool on all four sides are preferred to those that surround only three sides, with the fourth side being the home. With only three sides covered, the child can access the pool from an unsecured back door, doggie door, or sliding glass door. Load bearing pool covers, door and gate alarms, pool alarms, and child wearable devices all contribute to the layers of protection.

C. Classes. The American Academy of Pediatrics recommends swim lessons for ALL children age 4 years and older and suggests swim lessons for kids age 1 to 4 years based upon
their individual developmental abilities.²⁹ There are favorable studies showing a lifelong benefit and reduced risk of death by drowning for kids enrolled in formal swim lessons under age four.³⁰^,³¹ Swim lessons should not replace touch supervision, but are part of the layers of protection. Parents and caregivers should also take age-appropriate CPR classes that include specific instructions for chest compressions and ventilation in pediatric cardiac arrest.

FIGURE 16.3. Example of Water Watcher tag. Copyright 2016 by Colin’s Hope. All rights reserved. This document may be copied and distributed for personal and educational purposes provided the content is unchanged. All reproductions must include this copy permission statement, the copyright notice, the Colin’s Hope Logo and website link, http://www.colinshope.org.

D. Devices. Safety equipment such as life rings, shepherd hooks, throw bags, and rescue buoys should be readily available and in good working order while around the water. Age-appropriate, properly fitted, United States Coast Guard-approved life jackets should be worn at all times when on the water, and strongly considered when around the water.

Many of these interventions are unique to high income countries and settings. With so many of the world’s drowning deaths occurring in low and middle income countries, additional strategies are employed, many with corollary to the wilderness EMS environment. The largest survey to date showed that most of the drowning deaths in this age group in Bangladesh occurred between the hours of 0900 and 1300, while dad as at work and mom was busy doing household chores.³² The creation of community day care “crèches,” providing locally sourced playpens, and water safety community “theater” have been effective in reducing the number of drowning deaths in resource-deficit environments.³³^,³⁴^,³⁵^,³⁶

Only gold members can continue reading. Log In or Register to continue