Cold water immersion is dangerous because water conducts heat away from the body approximately 25 times faster than air of the same temperature, quickly leading to hypothermia. The immediate first aid goal is to stop this cooling process and prevent the body’s core temperature from dropping to dangerously low levels. Immediate and appropriate action is necessary to prevent severe complications, including cardiac arrest, which can occur even after the person is pulled from the water.
Immediate Stabilization and Gentle Handling
The moment a person is removed from cold water, improper handling can cause a sudden, fatal complication known as circum-rescue collapse or afterdrop. This phenomenon involves the reintroduction of cold, acidic blood from the extremities into the core circulation, which can trigger ventricular fibrillation (cardiac arrest). Therefore, all movements must be executed with the utmost gentleness to avoid physically stimulating the heart.
The victim should be rescued and moved in a near-horizontal position whenever possible to prevent a sudden drop in blood pressure. Once ashore, the person should be moved immediately to a sheltered, dry location and insulated from the cold ground using a blanket or other material. Avoid allowing the person to walk or exercise, as this activity forces cold blood back toward the heart, lungs, and brain.
The rescuer must quickly assess the person’s Airway, Breathing, and Circulation (ABCs). Even if the person appears unconscious with no clear pulse or breathing, resuscitation efforts should begin immediately if the rescuer is trained. Rough handling, rubbing, or vigorously massaging the limbs is strictly prohibited, as this action accelerates the movement of cold blood to the core.
Core Rewarming Techniques and Supplies
The most immediate action is the removal of all wet clothing. Wet garments conduct heat away from the skin, and they must be replaced by dry layers, sleeping bags, or specialized insulating materials like Mylar blankets. This application of dry insulation is known as passive external rewarming, which relies on the person’s natural ability to generate heat.
For a person who is conscious and able to swallow, give warm, non-alcoholic, and non-caffeinated fluids. Warm drinks, such as broth or sweetened beverages, help raise the internal temperature and provide readily available energy. Alcohol and caffeine must be avoided because they promote vasodilation and increased heat loss, working against the goal of core rewarming.
Active external rewarming involves applying heat only to the core areas of the body: the neck, armpits (axilla), and groin. These areas contain large blood vessels close to the surface, allowing for efficient heat transfer to the body’s core.
Heat should never be applied directly to the arms or legs or via extreme heat sources like hot water or heating pads. Applying heat to the limbs can cause the rapid return of cold blood to the core, risking the fatal afterdrop effect. Appropriate supplies for active rewarming include chemical heat packs, warm water bottles wrapped in cloth, or the rescuer’s body heat applied to the victim’s trunk.
Monitoring for Secondary Complications and Medical Transport
Cold water exposure is a serious medical event that requires professional assessment, and emergency services should be called immediately. All victims of significant immersion should be transported to a hospital for observation, even if they appear recovered, due to the risk of latent complications.
Monitoring for changes in the person’s mental status is paramount, as confusion, slurred speech, or drowsiness can indicate worsening hypothermia. The cessation of shivering is another serious sign, meaning the body has exhausted its ability to generate heat. Until professional help arrives, the person should be kept insulated and flat, minimizing all activity.
Secondary complications, such as pulmonary edema or respiratory distress, may develop hours after the rescue. The hypothermic heart is electrically unstable, and irregular heartbeats can occur even during the rewarming process. Medical professionals manage aggressive internal rewarming techniques, such as warmed intravenous fluids, necessary in severe cases.