Drowning is defined as a process of experiencing respiratory impairment from submersion/immersion in a liquid medium. To delineate the incident's outcome, this is further divided into descriptive terms such as death, morbidity, and no morbidity. Wet drowning, dry drowning, and near-drowning are no longer accepted terms, although they may still be used when discussing drowning.
Drowning is a major public health problem, especially in children. Drowning usually occurs in a rapid fashion and is most often silent. Individuals who thrash wildy in water while drowning are rare. In most cases, a motionless individual floating in water who rapidly disappears beneath the surface is the classic scenario.
Drowning can occur in both warm and cold water. In many cases, cold water can be protective especially in children. The most immediate threat in drowning is dysfunction of the cardiac and CNS systems. Hypoxemia and acidosis need to be corrected immediately if mortality is to be avoided. Even those who survive may develop a vegetative state due to the prolonged cerebral hypoxia.
Accidental or deliberate exposure to submersion in water or other liquid substances that inhibit the body's ability to oxygenate tissues and organs.
Risk factors for drowning include:
- Head trauma
- Cardiac arrhythmia
- Alcohol and drug use
- Panic attack
- Myocardial infarction
- Poor judgment
- Scuba diving
- Natural disaster
In infants, the cause is often accidental and may occur in the bathtub or even the bathing pail. Most infant deaths occur within 5 minutes of a lapse in supervision. Older children tend to drown in the swimming pool. Often the gate or the fence to the pool is open and the child just jumps in. Adults tend to drown in lakes, rivers, and the sea. In many adult cases of drowning, there may be an associated injury, like diving in shallow waters and hitting a rock.
Worldwide, drowning accounts for an estimated 360, 000 deaths annually. This represents 7% of all injury-related fatalities and is the leading cause of death among young males. It is estimated that 4, 000 fatalities occur each year in the United States. Furthermore, it is estimated that for every fatal drowning, four non-fatal drowning victims seek medical care. Fifty percent of those patients require hospital admission and interventions. There are three age-related peaks of victims which include small children (younger than 5), adolescents, and the elderly. Patients may drown in bathtubs, pools, large bodies of water or even rain-filled buckets in the yard. Risk factors for drowning include children and teenagers, residents of southern states, occurring during summer months, concomitant drug or alcohol use, and associated medical problems including dysrhythmias or epilepsy.
When a person suffers from submersion or immersion in a liquid medium, vital tissues may become hypoxic and acidotic which may result in cardiac dysrhythmias (progressing from tachycardia, bradycardia, pulseless electrical activity, and asystole). Aspirated fluid can lead to surfactant washout and dysfunction, increased permeability of the alveolar-capillary membrane, decreased lung compliance, and ventilation/perfusion ratio mismatching. This can result from minor to no respiratory complaints to fulminant non-cardiogenic pulmonary edema, with a clinical picture similar to adult or acute respiratory distress syndrome (ARDS). The highest morbidity and mortality are related to cerebral hypoxia, and management is aimed at reversing hypoxia as quickly as possible. Interestingly, hypothermic exposure with the incident may be tissue-protective, although may result in an increased occurrence of cardiac dysrhythmias.
Determination of the toxicity of the water that the victim was immersed in (eg saltwater versus freshwater) is of little importance in non-fatal drowning. Volume or serum (electrolyte) changes only occur when a significant volume of fluid is aspirated. It is more important to note if the fluid was obviously contaminated (sewage), as those patients are highly prone to pulmonary infection and prophylactic antibiotics may be warranted at presentation. Additionally, current recommendations state that routine use of cervical spine immobilization and imaging is not warranted unless the history or exam suggests that the patient suffered from a traumatic injury.
At least 20% of individuals develop tight laryngospasm that lasts even after cardiac arrest. These victims seldom aspirate any fluid and are said to have dry drowning.
The two major sequelae of drowning are to the CNS and cardiac system. Within 2 minutes most victims lose consciousness and within 4-6 minutes will develop irreversible brain injury. Global CNS hypoperfusion induces releases of excitotoxic neurotransmitters, free radicals, and lipid peroxidation. Cerebral edema followed by autonomic instability often results followed by ST-segment changes, indicating stress-related myocardial damage. The hypoxemia also induces ventricular arrhythmias and severe pulmonary hypertension.
History and Physical
The history should determine the circumstances surrounding the drowning; one needs to know if the individual died accidentally or if it was a homicide or suicide. Intentional deaths in newborns are not uncommon and the risk factors include:
- Maternal depression
- Unwed mother
- Young mother
- Financial crises
- Inability to cope with a newborn
Someone who is drowning or nearly drowning usually has a history of struggling to breathe after an extended period of water submersion. The skin may appear blue or pale from lack of oxygen in the blood. The patient may be in respiratory distress with apnea or shallow breathing, have an altered level of consciousness, be coughing, fatigued, or have other neurological findings.
Labs and/or imaging studies are not always warranted in well-appearing, normoxic, asymptomatic patients. If obtained, the workup should be directed towards the patient’s history and exam (eg for continued hypoxia a chest x-ray and blood gas may be warranted or for altered mental status a head CT, blood glucose, blood gas, toxicology analysis, ethanol level, and a metabolic panel may be needed). The most common laboratory abnormality noted in these patients is metabolic acidosis secondary to a lactic acidosis. Electrolyte abnormalities are uncommon in non-fatal drowning patients despite the type of fluid in which the patient was immersed.
A chest x-ray is not required in all drowning victims. Moreover, the initial chest x-ray has little correlation with the patient’s clinical course or outcome. However, one should be obtained with continued hypoxia or worsening respiratory symptoms. Patients may develop a non-cardiogenic pulmonary edema/ARDS-type presentation and should be treated accordingly. Routine use of glucocorticoids, diuretics, and empiric antibiotics is not currently recommended. Antibiotics should be withheld until the patient begins to develop infectious signs and/or symptoms. In significantly unstable patients, providers may consider using extracorporeal membrane oxygenation (ECMO) as salvage treatment for refractory hypoxia or hypothermia. Therapeutic hypothermia has also been discussed as being a beneficial treatment adjuvant.
- Factitious disorder imposed on another(Munchausen by proxy)
- Fibrillation in emergency medicine
Only patients who are alert or mildly confused at the initial presentation have a good prognosis. Victims who are comatosed usually fair poorly. Those who are comatosed and resuscitated with CPR often develop severe brain injury and hypoxic encephalopathy. At least 10-30% of children with brain damage require long term rehabilitation. Hypothermia can protect the brain in some children. Other risks of drowning include aspiration, ARDs, and death.
Pearls and Other Issues
Patients with mild to no symptoms may be observed in the emergency department for four to eight hours, and if they continue to do well, they may be discharged home with return precautions given. Symptomatic patients may warrant further observation with inpatient admission to the appropriate area (floor vs. intensive care depending on the severity of their symptoms).
Enhancing Healthcare Team Outcomes
The management of drowning is with an interprofessional team that includes the emergency department physician, neurologist, anesthesiologist, intensivist, nurses and EMS services.
Initial management of the patient includes delivering oxygen via nasal cannula, non-rebreather, non-invasive positive pressure ventilation, or endotracheal tube. Oxygen should be titrated to maintain oxygen saturation between 92% - 96% and to avoid over oxygenation. Nebulized albuterol may be given for bronchospasm. Cardiac support should be employed. Advanced cardiac life support (ACLS) protocol should be followed if needed. Infusion of crystalloids, and at times vasopressors, may be needed for refractory hypotension.
The primary care provider and nurse practitioner play a vital role in prevention. It is estimated that more than 85% of drowning cases could be prevented with supervision, swimming instruction, technology, regulation, and public education. Parents should never leave infants unsupervised near any water. Children should always be told to wear life vests when in the water. In addition, it is vital that the parent or caregiver know how to perform CPR. Parents should be told to have a gate around the pool and the use of alcohol and recreational drugs around the area should be forbidden. Less than six percent of all persons who are rescued by lifeguards need medical attention in the hospital. Education is fundamental to preventing drowning accidents.
The prognosis of patients with drowning depends on how long the individual was hypoxic and the time for resuscitation. In most cases, survivors are left with residual neurological sequelae. (Level V)