Activities in the outdoor and austere environments often involve exposure to bodies of water. With this exposure, especially if by way of water sports and recreation, comes the risk of drowning. In 2019, the Wilderness Medical Society published an updated version of its Practice Guidelines for the Treatment and Prevention of Drowning. The aim of these guidelines are to provide evidence-based recommendations to individuals and groups recreating in austere environments to 1) decrease the incidence of drowning during these activities and 2) decrease morbidity and mortality due to drowning by way of improved resuscitation and care.

Statistics

Drowning represents a huge disease burden. Approximately 360,000 deaths globally are attributed to drowning every year, with the highest-risk age group worldwide being children ages 1-4. This predominance in younger patients carries with it dire personal, emotional, and financial consequences. Furthermore, the actual burden on all ages is likely underreported because most studies omit drowning deaths from storms, floods, boating, and only address fatal drownings.

Terminology

In 2002, the World Congress on Drowning established the uniform definition of drowning as “the process of experiencing respiratory impairment due to submersion or immersion in liquid.” This definition includes patients who survive the process—a conservative estimate is that for every fatal drowning, another five persons seek emergency care for non-fatal drowning. The 2002 definition has been adopted by major consensus organizations in the United States and internationally who engage in drowning prevention and treatment.

There are only three outcomes from the drowning process:

• Fatal drowning
• Non-fatal drowning with injury
• Non-fatal drowning without injury

The following modifiers are no longer considered legitimate or clinically meaningful terminology and should not be used in association with drowning: near, wet, dry, active, passive, saltwater, freshwater, delayed, or secondary drowning.

Rescue of the Drowning Patient

People without formal water rescue training should only attempt rescues from a safe location by reaching, throwing, or rowing to the drowning patient. Entering the water to perform a rescue should be attempted only by persons with specific training to operate in that dangerous environment. Few studies have been conducted on the effectiveness of different water safety devices (eg, rescue tubes, rescue cans, throw bags, life rings). What we do know is that proper and effective use of these devices requires basic knowledge of their function combined with regular practice. If specialized rescue equipment is available, participants should be familiar with the location and purpose of this equipment, and designated rescue personnel with proper training should use it in the event of a water rescue.

In-Water Resuscitation

In-water resuscitation (IWR) is defined as the “attempt to provide ventilations to a drowning patient still in the water.” IWR should only be considered by a rescuer with adequate training, ability, and equipment to safely and effectively perform the skill. The aquatic conditions must be sufficiently safe for the rescuer to perform IWR and the point of extrication from the water must be far enough away to justify this technically difficult task. If conditions are too hazardous to safely perform IWR, rapid extrication is indicated without a delay. Chest compressions should never be attempted in the water.

CPR Priorities

Supplying oxygen to the brain is critical in drowning resuscitation. Establishing an airway and providing oxygen are the priorities in the initial resuscitation. For the patient in cardiac arrest, provide positive pressure ventilations in addition to chest compressions using the traditional Airway-Breathing-Circulation (A-B-C) sequence of resuscitation, not the C-A-B sequence. Advanced airways such as intubation may be used the same as they would be for non-drowning indications.

Compression-only CPR is likely to be of little to benefit in drowning resuscitation, and its use should be limited to bystanders not trained in rescue breathing. All people whose role might involve responding to a drowning person (eg, parents, trip leaders, lifeguards) should obtain CPR training that includes both rescue breathing and chest compressions.

Oxygen

When resuscitating a drowning patient, oxygen should be delivered at the highest concentration available. For patients in respiratory distress or not breathing, positive pressure is preferred over passive ventilation. If multiple modalities are available, the method that most effectively delivers the highest concentration of oxygen should be used.

Automated External Defibrillator (AED)

Because ventricular fibrillation (the heart rhythm addressed by defibrillators) is rare in drowning, the initial interventions for drowning of oxygenation and ventilation should not be delayed trying to get or apply an AED. Cardiac dysrhythmias can precipitate drowning in older persons and young, otherwise healthy persons, so if the AED is available, it should be used once oxygenation and ventilation have been initiated. AEDs can be used in wet environments and on boats, including on moving boats and boats with a metal surface like canoes.

Heimlich Maneuver

The Heimlich maneuver is not recommended for resuscitating drowning patients.

Spinal Trauma Precautions

Treatment considerations for possible spinal trauma precautions should be carried out in accordance with the most current version of the Wilderness Medical Society Clinical Practice Guidelines for Spinal Cord Protection.

Cold Water Survival

Use of an USCG approved, properly fitted life jacket that is appropriate for the conditions provides the best chance of surviving an unexpected fall into cold water. The hyperventilation caused by the cold shock response can precipitate drowning in the first one to three minutes. Upon falling into cold water, subjects should distance themselves from any immediate life threats, then remain calm and focused and control breathing by taking slow deep breaths. They should consider physical capabilities, location, resources, and chances of rescue to determine whether to swim to safety.

If a decision is made to swim to safety, this should be done as soon as possible after the cold shock response, but before physical capabilities deteriorate from the effects of cold stress.

If a decision is made to await rescue, an attempt should be made to remove as much of the body from the water as possible. All clothing should remain on, unless it hampers buoyancy. If the person remains immersed and has a flotation garment on, the heat escape lessening position should be maintained if possible. In a group, the huddle position may be used. If prolonged rescue is expected, it might be beneficial to attach oneself to a buoyant object or to a surface out of the water to improve the chance for survival.

Figure 1: Heat escape lessening position (used with permission from www.Boat-Ed.com).

Figure 2: Huddle formation (used with permission from www.Boat-Ed.com).

Post-Resuscitation Management

Mechanical ventilation for drowning patients should follow acute respiratory distress syndrome (ARDS) protocols. Noninvasive positive pressure ventilation (NIPPV) has been used successfully in the out-of-hospital setting and may be used in alert drowning patients with mild to moderate respiratory symptoms. Caution should be taken with any patient who has altered mental status or who is actively vomiting due to concern for aspiration.

There is no evidence to support antibiotic or corticosteroid use in the out-of-hospital setting for initial treatment of drowning itself.

Although some guidelines recommend induced hypothermia in postcardiac arrest care, there is insufficient evidence to either support or discourage inducing or maintaining therapeutic hypothermia in drowning patients. The guidelines authors did note that there might be benefit to discontinuing rewarming interventions after a hypothermic drowning patient has reached the temperature range of therapeutic hypothermia, but that it has been insufficiently studied to support an evidence-based recommendation.

Disposition in the Wilderness

1. Any patient with abnormal lung sounds, severe cough, frothy sputum, foamy material in the airway, depressed mentation, or hypotension warrants immediate evacuation to advanced medical care if risks of evacuation do not outweigh potential benefit.
2. Any patient who is asymptomatic (other than a mild cough) and displays normal lung auscultation may be considered for release from the scene. Ideally, another individual should be with them for the next 6 hours to monitor for symptom development or the patient should be advised to seek medical assistance if symptoms develop.
3. If evacuation is difficult or may compromise the overall expedition, patients with mild symptoms and normal mentation should be observed for 6 hours. Any evidence of decompensation warrants prompt evacuation if the risks of evacuation do not outweigh the potential benefit.
4. If evacuation of a mildly symptomatic patient has begun and the patient becomes asymptomatic for 6 hours, canceling further evacuation and continuing previous activity may be appropriate.

Cessation of Water-Based Rescue and Resuscitation

Based on context and resources, it might be reasonable to cease rescue and resuscitation efforts when there is a known submersion time of greater than 30 minutes in water >6°C (43°F), or greater than 90 minutes in water <6°C (43°F), or after 25 minutes of continuous cardiopulmonary resuscitation.

Drowning Prevention

All patients with coronary artery disease, prolonged QT syndrome or other ion channel disorder, autism, seizure disorders, or other medical and physical impairments should be counseled about the increased risk of drowning. They should also be taught steps to mitigate the risk, such as buddy swimming and rescue devices, should they choose to participate in water activities. Given the higher rate of drowning in patients with epilepsy, patients should be counseled to never swim without direct supervision.

Formal swim instruction is recommended for all children over age 1. For swimming ability to serve as drowning prevention, people should have at a minimum enough experience and physical capability to maintain their head above water, tread water, and make forward progress for a distance of 25 meters (82 feet).

When boating or engaging in water sports for which lifejackets are recommended, people should wear properly fitted life jackets that meet local regulatory specifications.

Alcohol and other intoxicating substances should be avoided before and during any water activities.

Published August 4, 2020

Volume 37, Issue 3

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