In the past, submersion events have been defined in various ways in the medical literature. The lack of consistency and standardization of terms makes research analysis and communication in the field difficult, confusing, and imprecise. In 2002, the International Liaison Committee on Resuscitation (ILCOR) approved guidelines for definitions and reporting of data related to drowning developed by international investigators and experts in the field.¹ Many terms, such as, “near drowned” which previously referred to survival of a submersion victim for longer than 24 hours as well as “wet” and “dry drowning” were abandoned. According to ILCOR, the term drowning should refer to a process resulting in primary respiratory impairment from submersion/immersion in a liquid medium. Submersion implies the entire body, including the airway is under water, while immersion merely describes being covered in water. The term drowned continues to indicate death from a submersion/immersion event.

EPIDEMIOLOGY

Drowning is a significant pediatric problem. In the United States, drowning is the second leading cause of traumatic death in children 1 to 16 years of age. From 1999-2007, drowning represented nearly 7800 unintentional deaths in this age range.² Toddlers and teenagers are particularly at risk given their unique developmental and behavioral stages, and males are two to four times more likely to drown than females.³ African American males aged 5 to 14 years have a 4- to 15-fold higher drowning rate compared with their white counterparts.⁴ Morbidity and mortality are high; 15% of admitted patients die, and 20% of survivors have permanent severe neurologic sequelae. Although most submersion events occur in open water sites, bathtubs, toilets, and buckets of water can be dangerous for infants and toddlers as well as children whose mental capacity may be permanently or temporarily impaired.

For the last several decades, however, the death rate from drowning in the United States has been declining. The death rate in 1970 was 3.87  deaths per 100,000 population and between 2005 to 2009, it was 1.29.^3,5 This is likely due to a combination of expanded and enhanced knowledge in the pathophysiology of the drowning process leading to the targeted treatments and avoidance of secondary insults in the care of drowning victims as well as increased awareness and education of the lay public in open water and pool safety and cardiopulmonary resuscitation.

PATHOPHYSIOLOGY

Hypoxemia is the final common pathway of injury in the drowning process which, if not interrupted, will ultimately result in profound tissue hypoxia and multiorgan failure. While the lungs are the primary and initial site of injury in the drowning process, the heart and the brain are the most important organs affected, often permanently, as they are particularly sensitive to even brief periods of hypoxia. During the initial phases of submersion, victims hold their breath and struggle until they reflexively breathe, causing the aspiration of fluid. This aspiration results in laryngospasm, and if it is sustained, the victims do not aspirate any more fluid. In most cases, however, the laryngospasm resolves and the victims aspirate more fluid. Because of progressive neurologic failure and the swallowing of fluid, victims often vomit and may aspirate gastric contents as well. Although the mechanisms of injury are different with freshwater versus seawater aspiration, there is no clinical significance unless submersion occurs in a hypertonic fluid, such as the Dead Sea. Acute impaired lung function results from loss of surfactant, caustic injury from aspirated contents, and pulmonary edema, all contributing to worsening hypoxemia. Atelectasis, ventilation-perfusion mismatch, and acute respiratory distress syndrome (ARDS) may result. Pneumonia may develop, but usually occurs later in the course, especially in intubated patients.

Hypoxic injury may occur in all end organs. Neurologic sequelae are often the most devastating for submersion victims. Hypoxic-ischemic injury causes cerebral edema and increased intracranial pressure. Submersion in very cold water may provide cerebral protection by slowing down cerebral metabolism, especially in children (hypothermia is covered in Chapter 173). The effects of hypoxemia on cardiovascular function include decreased cardiac output and increased systemic and pulmonary resistance. Arrhythmias may occur secondary to hypoxemia, hypothermia, or other metabolic derangements. Common arrhythmias include sinus bradycardia, pulseless electrical activity, and asystole; ventricular fibrillation is rare. Less common sequelae include renal insufficiency or failure, acute tubular necrosis, and disseminated intravascular coagulopathy.

The initial presentation of a submersion victim can range from asymptomatic to critically ill. This initial presentation often reflects the severity of injury sustained as well as the projected outcome. Children who present alert and without respiratory distress usually continue to stay well, with no deterioration in their clinical status. Critically ill patients often present cold, poorly perfused, and ashen in color dead, and unfortunately, despite most resuscitative efforts, the outcome is often poor. Body temperature rapidly decreases in submersion victims. Lung sounds may be coarse, clear, or absent. Pulses may be diminished or absent, and perfusion is usually decreased due to peripheral vasoconstriction from hypothermia.

The history focuses on identifying the life-threatening injury or insult, determining the details of the submersion and rescue, and obtaining the pertinent medical history (Table 174-1). Basic life support by laypersons appears to be critical in patient survival.⁶ The physical examination consists of an immediate assessment of the patient’s airway, breathing, and circulation (ABCs), followed by a full head-to-toe examination.

For older children, the diagnosis of submersion is obvious. However, it is important to consider comorbidities that may have placed the patient at higher risk, such as long QT syndrome, alcohol or drug intoxication, or a poorly controlled seizure disorder.^7,8 Although cervical spine injuries are rare, they should be considered, especially if the patient was diving into the water.⁹ Inflicted submersion should be suspected when the reported history is not consistent with the child’s developmental stage or physical examination. Inflicted submersions are seen predominantly in children younger than 2 years, and they often occur in the bathtub.¹⁰

The initial evaluation and treatment proceed in tandem, so they are discussed together.