By David Tiber, MD
"I only looked away for a minute."
Those were the words of a father who was bathing his young son. The child silently slipped underwater and wasn't breathing when his father looked over and frantically pulled him from the bathtub. Fortunately, the father knew CPR and the child survived. He was brought to the hospital and monitored in the Pediatric Intensive Care Unit, at risk for ongoing and delayed lung injury.
This story has been repeated countless times, and it is often very similar -- a brief look away, and suddenly a child is fighting for his/her life.
When someone is submersed in water and struggling to breathe, there is a cascade of events. At first, they hold their breath. When this is no longer possible, water enters the airway. When the vocal cords are hit by water, they spasm shut. This prevents water from entering the lungs, but also doesn't allow air exchange. At some point, the vocal cords will relax and then water rushes into the lungs. The water that reaches the lungs can wash out surfactant, which is a fluid the lungs rely on to prevent collapse. Without surfactant, alveoli collapse, and water can be pulled into the lungs from the surrounding tissues, called pulmonary edema, which further worsens the ability to breathe. This injury may develop over time. If the person isn't rescued, the outcome is unfortunately obvious. If they are rescued, they are most likely to be no worse for wear. In very rare cases, less than 1% of the time, the lung injury may be ongoing, causing symptoms hours later. This is what is people refer to as "dry drowning."
"Dry drowning," a term used to describe someone who becomes progressively more ill hours after coming out the water, is actually a misnomer. The World Congress on Drowning defines drowning as "respiratory impairment from submersion/immersion in liquid" and, therefore, no drowning event can be "dry." Injury to the lung, however, can continue to accumulate after being removed from the water.
This delayed injury can create non-specific signs that affect several body systems. Neurologically, someone may be confused, agitated, have a headache, or just be exhausted. From a respiratory standpoint, they may be coughing, breathing fast or hard, or have shortness-of-breath. They may also experience vomiting or abdominal pain as gastrointestinal manifestations. Additionally, their heart may be beating abnormally fast. Young children cannot verbalize these feelings, so if they are acting abnormally, it's important to watch them closely and seek help if you're concerned.
Drowning peaks in two age groups: those under 5 years old, and again in adolescents/young adults. The first group, young children, can drown in surprisingly small amounts of liquid: bathtubs, buckets of water, kiddie pools -- it only takes a few inches of water. The older group drowns more often in lakes, rivers, oceans, and swimming pools, and are more likely to involve intoxication.
The most important thing you can do to prevent delayed injury from drowning is to not let a drowning event happen in the first place. Children must be closely watched around all bodies of water, no matter how small. If your child is in a pool, be in the pool with them. Pools should also have fences around them with child-resistant gates. It only takes seconds for someone to go underwater, so watching your phone (or not paying attention for another reason) for any amount of time can have deadly consequences. Older children/adults should avoid swimming alone and avoid being intoxicated. Also, unlike the thrashing and screaming you see in the movies, drowning is nearly always silent -- there is no dramatic yelling or splashing. In addition, getting trained in CPR is always a solid idea. The knowledge of what to do while waiting for help to arrive can make a huge difference in outcome.
Again, most people who experience submersion are going to be just fine if pulled from the water quickly. However, if you have concerns or notice the above signs, it's best to seek medical help.
David Tiber, MD, is director, Pediatric Sedation Service, at UMass Memorial Medical Center in Worcester. He is also an assistant professor of pediatrics and anesthesia at UMass Medical School.