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Friday, June 16, 2017

Drowning in a Sea of Misinformation: Dry Drowning and Secondary Drowning

BY SETH COLLINGS HAWKINS, MD; JUSTIN SEMPSROTT, MD; & ANDREW SCHMIDT, DO, MPH

Earlier this month a young child died following days of vomiting. He had been in shallow water in a Texas dike about a week before his death. The story was picked up as an alleged case of a rare condition called dry drowning or secondary drowning. (CNN. June 9, 2017; http://cnn.it/2rECrOV.) The media accounts went viral, spreading significant fear in parenting communities and among those learning about these alleged conditions from the news or social media.

Every death is tragic, especially when it is a child's. Our heartfelt sympathies go out to the family and to those who treated the patient. Drowning deaths are a common cause of pediatric death, and we need to be particularly vigilant about sharing correct, meaningful, and medically credible information.

Unfortunately, there is significant misinformation in the media reports of this case, and we hope this evidence-based discussion of drowning and the best practice medical care of drowning patients will help set the record straight.

1. The medical definition of drowning is "the process of experiencing respiratory impairment from submersion/immersion in liquid." (Definition of Drowning: A Progress Report. Bierens J, Drowning 2e. Berline: Springer, 2014.) Drowning has only three outcomes: fatal drowning, nonfatal drowning with injury or illness, or nonfatal drowning without injury or illness.

2. There are no medically accepted conditions known as near-drowning, dry drowning, and secondary drowning. The World Health Organization, the International Liaison Committee on Resuscitation, the Wilderness Medical Society, the Utstein Style system, the International Lifesaving Federation, the International Conference on Drowning, Starfish Aquatics Institute, the American Heart Association, the American Red Cross, and the U.S. Centers for Disease Control and Prevention (CDC) all discourage the use of these terms. (WHO, http://bit.ly/2rECxWT; Circulation 2003;108[20]:2565; Wilderness Environ Med 2016;27[2]:236, http://bit.ly/2sAR3nL; International Life Saving Federation, http://bit.ly/2s9hi33; Handbook on Drowning: Prevention, Rescue, Treatment. Berlin: Springer, 2006; Starfish Aquatics Institute, http://bit.ly/2sACGQd; Circulation 2005;112:IV-133, http://bit.ly/2tb2pLU; American Red Cross Statement on Secondary Drowning, 2014; Morb Mortal Wkly Rep 2004;53:447; Snopes, http://bit.ly/2sHayL1; CDC, http://bit.ly/2sxCsZh.)

Unfortunately, these terms still slip past the editors of major medical journals, allowing their use to be perpetuated. These terms are most pervasive in the nonmedical press and social media, where the term drowning seems to be synonymous with death. We must find a better way to educate the public on how to discuss drowning as a process, with a spectrum ranging from mild to moderate to severe with fatal or nonfatal outcomes.

Near-drowning. Historically, drowning was used to indicate death, while near-drowning was used to describe patients who survive. But many people suffer from strokes, cardiac arrest, or car collisions every year, and we wouldn't consider them near-strokes, near-cardiac arrest, or near-car collisions just because the person survived. The same is true for drowning and near-drowning. A person can drown and survive the same way that a person can have a cardiac arrest and survive.

Dry drowning. Dry drowning is a term that has never had an accepted medical definition, and has been used at different times to describe different parts of the drowning process. Many media reports use it as a synonym for secondary drowning (described below), but in the past, it was used to describe the finding that the lungs of drowning victims contained no water in about 10 to 20 percent of autopsies. About 10 to 20 percent of the time, no water is found in the lungs at autopsy. Laryngospasm may play a role in some of these cases. During the drowning process, very little water actually enters the lungs, typically less than 2 mL/kg body weight.

This would mean only 30 mL, or one ounce, of water would enter the lungs of an average 15 kg (33 lb.) 3-year-old. If a child is underwater for more than a minute or so, then the main problem is a lack of oxygen to the brain, and CPR should be started to restore oxygen to the brain. If the person is rescued before the brain runs out of oxygen, then that small amount of water in the lungs is absorbed and causes no problems, or it can cause excessive coughing that gets better or worse over the next few hours. The management is the same regardless of whether small amounts of water are present, so this distinction between wet and dry drownings was abandoned as clinically meaningless years ago by drowning specialists.

Secondary drowning. Sometimes known as delayed drowning, this term also has no currently accepted medical definition. Its historical use reflects the reality that patients may sometimes worsen after water exposure. The take-home point is that anyone who experiences respiratory symptoms after a drowning incident (using the modern definition above) should seek medical care. There has never been a case published in the medical literature of a patient who received a clinical assessment, was initially without symptoms, and who later deteriorated and died. People who have drowned and have minimal symptoms will either get better or worse within two to three hours.

We know from a study of more than 41,000 lifeguard rescues that 0.5 percent of patients with initially minimal symptoms and five percent of patients with initially moderate symptoms ultimately died of drowning. (Chest 1997;112[3]:660.) This is the valid part of the concern about drowning patients who initially have only minimal symptoms: They should seek medical care. What are minimal symptoms? Using an experience familiar to almost everyone, we recommend that care be sought if symptoms seem any worse than the experience of a drink going down the wrong pipe at the dinner table or severe coughing that does not resolve in minutes.

Usually these patients can be observed for four to six hours in an emergency department and be released if normal. More significant symptoms would be persistent cough, foam at the mouth or nose, confusion, or abnormal behavior, all of which warrant attention. Drowning deaths do not occur due to unexpected deterioration days or weeks later with no preceding symptoms. The lungs and heart or their passages do not fill up with water, and water does not need to be pumped out of the lungs.

As noted earlier, only small amounts of water are needed to disrupt the surfactant that lines the cells in the lung responsible for exchanging oxygen and other gases. The problem in drowning, especially in cases of mild drowning that worsens, is surfactant disruption, not a measurable level of fluid in the lungs that fills up like a cup and prevents breathing. After a mild or moderate drowning, inflammation and infections in the lungs can cause the initial symptoms to get worse. Parents should seek additional care whenever a child has an excessive cough, isn't breathing normally, or isn't acting right immediately after being pulled from the water. If the child is 100 percent normal upon exiting the water and concerning symptoms develop more than eight hours later, then parents should seek care and providers should consider diagnoses other than primary drowning. In our experience, spontaneous pneumothorax, chemical pneumonitis, bacterial or viral pneumonia, head injury, asthma, heart attack, and chest trauma have been misattributed to delayed drowning.

3. Nonfatal drownings of this sort are common. Cases where a person has mild to moderate symptoms after a drowning incident, such as cough, pulmonary edema (fluid in the lungs), or confusion, are far more common than fatal drownings. It is often quoted in the media that this type of drowning is rare, but that is incorrect. It is actually the most common presentation of drowning. It is estimated that there are five nonfatal drownings for every fatal drowning in children. (AHRQ; http://bit.ly/2ta8RTxCDC; http://bit.ly/2rz1d85.) There are almost 13,000 emergency department visits per year for drowning (AHRQ; http://bit.ly/2ta8RTx), with only about 3,500 drowning deaths in the United States. (CDC; http://bit.ly/2rz1d85.) In fact, 95 to 99.5 percent of patients who have mild to moderate symptoms and a normal blood pressure survive. (New Engl J Med 2012;366[22]:2102; http://bit.ly/2sGEU02.)

What is rare is for these minimally symptomatic cases to progress to death. Similarly, this is also true of heart attacks: Most cases don't progress to death. Nonetheless, they can certainly deteriorate or progress, which is why we encourage people to seek care immediately when they have warning signs like chest pain. The warning signs for drowning are submersion or immersion followed by difficulty breathing, excessive coughing, foam in the mouth, and not acting normally. Subsequent death or complication from drowning is no more a secondary or delayed drowning than subsequent death or complication from heart attack is a secondary or delayed heart attack.

4. How do we communicate better information through the media? Some media reports noted that the terms dry drowning and secondary drowning are discredited in the medical community, but they went on to use them throughout their story. Often, we hear that these terms are more familiar to the public, which is likely true. Of more concern is that some physicians continue to use these terms (and older definitions of drowning that equate drowning exclusively with death) during media interviews and in clinical care and publications. The paradox is that the medical community invented these terms, not patients. The novelty of this storyline—and its appeal to media outlets—is precisely the unfamiliarity of these terms to the general public and the perceived mysterious looming threat. As clinicians and researchers, we should drive popular culture definitions, not the other way around. Rather than discuss these terms as semantics or technicalities, we have an opportunity to present facts, highlight the dangers of drowning and the importance of prevention, and to promote simpler but correct language that is easier for us and our patients to understand.

5. The bottom line. Near, dry, wet, delayed, and secondary drownings are not medically accepted diagnoses. We urge you to abandon these terms in favor of understanding and communicating drowning as a process that can be mild, moderate, or severe with fatal or nonfatal outcomes. Someone who drowns and survives has suffered a nonfatal drowning.

Drowning is a leading cause of preventable pediatric death. The danger is real and not esoteric or rare, and we should use this as an opportunity to discuss with the media and our patients the most important tool for treating drowning—primary prevention. Such prevention includes swimming lessons, touch supervision for toddlers, life jacket usage, appropriate pool fencing (four-sided with a locking gate), and continuous, uninterrupted supervision while kids are in the water, even if a lifeguard is present. If a drowning incident still occurs, anyone with symptoms should receive medical attention. Alternative diagnoses should be sought for those with an asymptomatic period of more than eight hours followed by other symptoms developing. Health care providers should understand and share modern drowning science and best practices, which will reduce fear, improve resource utilization, and prevent potentially deadly consequences due to misunderstanding or misinterpretation of incorrect terminology.


​Additional Resources

Find peer-reviewed information in the practice guidelines from the Wilderness Medical Society (Wilderness Environ Med 2016;27[2]:236; http://bit.ly/2sAR3nL) and an excellent review from the New England Journal of Medicine. (2012;366[22]:2102; http://bit.ly/2sGEU02.) There are also good review articles specifically written for pediatric (PEMNetwork Blog; http://bit.ly/2rEm9Wh) and rural emergency medicine providers (J Rural Emerg Med 2015;2[1]:1; http://bit.ly/2sH9nev) as well as for family practitioners (Am Fam Physician 2016;93[7]:576; http://bit.ly/2roz8w2) and lifeguards. (Starfish Aquatics Institute; http://bit.ly/2sACGQd.)


A​bout the Authors

Dr. Hawkins is an emergency physician in active clinical practice, an assistant professor at Wake Forest University School of Medicine, and a lifelong competitive swimmer. He is the medical director of Starfish Aquatics Institute, Landmark Learning, the Burke County EMS Special Operations Team, and the North Carolina State Parks system. He is an author of numerous medical textbook chapters about drowning and of the Wilderness Medical Society's evidence-based practice guidelines for drowning. He serves as a board member of Lifeguards Without Borders, and is a certified wilderness lifeguard instructor. Follow him on Twitter @hawk_sc.

Dr. Sempsrott is an emergency physician who started out as a beach lifeguard in 1996, and was a founder of the nonprofit Lifeguards Without Borders, now serving as its executive director. He also serves as the medical director for the International Surf Lifesaving Association, Starfish Aquatics Institute, and Innovative Attraction Management Starguard Elite. He is a founding member of the International Drowning Research Alliance and a frequent author and lecturer on drowning prevention, rescue, and treatment.

​Dr. Schmidt is an assistant professor with the University of Florida-Jacksonville Department of Emergency Medicine, where he also serves as deputy medical director for the TraumaOne Flight Program. His specific areas of research and teaching are drowning resuscitation and prehospital medicine. Other positions held include the medical director for Jacksonville Beach Ocean Rescue and a director of Lifeguards Without Borders.