How to help families enjoy summer swimming without excessive fear or concern.
As the weather warms up and kids run to the pools, drownings are a significant concern among pediatricians and other medical professionals who care for children. I acknowledge that there may be some confusion about various aspects of drownings. The basic pathophysiology of drownings is important to understand, so that there is more clarity about some misunderstandings that circulate during this time of year. Common misunderstandings include the idea of dry drownings and secondary or delayed drownings.
When it comes to drownings, the foundation of the pathophysiology of drownings is hypoxemia from water being aspirated into the lungs, which causes lung damage or the inability of oxygen to be transmitted from the alveoli to the blood. The end result is multisystem organ injury from cells, tissues, and organs becoming deprived of oxygen and, subsequently, not working normally.
The heart and brain account for the most devastating and apparent complications of drownings. Without oxygen, the myocardium stops functioning. It is a domino effect of organ injury once the heart ceases to function because of a lack of oxygen. Once the brain is deprived of oxygen, there can be significant injury that may not be reversed even if the rest of the organs survive the drowning and start functioning normally. Thus, the primary goal of treatment and support is to restore circulating oxygen in the blood as soon as possible to prevent devastating injury to the heart and brain.
The Drowning Fears
Besides the fear of death from drowning, there is also the fear of permanent brain injury. Death and disability from drownings are legitimate fears and, unfortunately, are not rare. With this in mind, misunderstandings about drownings can occur fairly easily, and families can be quite susceptible to being misinformed by what they see from various sources of information and the misinterpretation of the pathophysiology of drownings. The misunderstandings that we usually encounter in the outpatient setting include the idea of dry drownings and secondary or delayed drownings.
There are really only two acceptable ways to describe drownings: fatal and nonfatal. Prior terms of near-drowning, dry drowning, secondary drowning, delayed drownings, and other terms are inaccurate. A child or adult either survives the drowning or does not. Survival with or without permanent injury is still termed a nonfatal drowning. Those who do not survive the drowning, either immediately or during some time afterward, suffer a fatal drowning.
A dry drowning implies that a person drowns without having water in their lungs. The concept evolved from individuals found dead in the water without fluid in their lungs. The underlying drowning concept is based on water being aspirated into the lungs and causing lung dysfunction to the point of not being able to move oxygen into the blood. So, having no fluid in the lungs usually means that person died from something else and happened to be in the water at the time of their death. Sure, there is the concept of the larynx spasming closed after being triggered by water trying to enter the airway. But, with the lack of oxygen, muscles usually relax and the larynx opens, allowing water flow into the lungs with time.
A secondary or delayed drowning is likely the most common reason we see children in the urgent care after a concern for drowning. The usual case goes like this:
A child is momentarily immersed in water and may have aspirated fluid, as evidenced by coughing afterward, but the child is acting and breathing normally. There is no apparent injury from the episode, but the parents are concerned about them developing problems with their lungs and symptoms of drowning either hours, days, or weeks later.
Some children can develop lung injury up to 8 hours after a significant aspiration, but they are usually somewhat symptomatic after drowning, with coughing, wheezing, trouble breathing, lower oxygen levels than normal, or shortness of breath. A child without these symptoms after the drowning episode usually will not develop lung injury hours later. Furthermore, worsening lung function will occur hours after the injury and definitely not days or weeks. So, the secondary or delayed drownings descriptors (sometimes also termed “dry drowning” by parents) are not accurate. If a child has a drowning episode of any severity and suffers progressive lung injury but did not require resuscitation and is acting fairly normally after the drowning, it is termed a nonfatal drowning and not a delayed or secondary drowning. The progressive lung injury follows the same drowning pathophysiology, except that the amount of water aspirated into the lungs was not significant enough to cause more severe initial symptoms. The prognosis for minor drownings with progressive symptoms is usually excellent. Drownings with a poor prognosis are those that result in the requirement for CPR or children who show signs of neurologic injury with a depressed level of consciousness immediately after the drowning episode.
The “take-home” messages are: 1) There is a consistent pathophysiology of drowning that causes lung injury, oxygen deprivation, and subsequent multiorgan injury (depending upon the severity of the drowning); and 2) There are only fatal and nonfatal drownings, and all other descriptors of drownings are inaccurate.
The problems caused by drownings either present immediately or as a progressive lung problem over hours. But, neither is surprising and both can be predicted based on the severity of the drowning. A child will not suffer a clinical decline from drowning over the course of days or weeks if there was no sign of initial lung injury. Confusion about how a drowning affects the body can generate misinformation. Most of this misinformation is not intentional and can be easily cleared up. Educating families about drownings is important, so that summer swimming can be enjoyed safely without excessive fear or concern.