It’s early March and while it’s still cold outside, the days are getting warmer and the snow that’s been around all winter is beginning to melt away. Shortly after 2 p.m., Medic 2115 is toned out for a report of a “child drowning” at a rural lake, 45 minutes away. While enroute dispatch updates the crew, reporting that the local volunteer fire department was sending divers into the water and conducting a search and rescue.
As the EMS crew arrives, they can see that the frozen surface of the lake has begun to thaw. Rescue personnel are working near the edge of an open hole in the thinning ice. It appears they are pulling the soaking wet, fully clothed body of a child out of the hole. She appears lifeless.
Bystanders reported seeing the girl plunge through the ice about 55 minutes ago. She was able to keep her head out of the water for only a few minutes before disappearing below the surface.
In the U.S., more than 3,800 people die from unintentional drowning annually.[1] It is the second leading cause of accidental deaths in children ages one to 14[2], and is a leading cause of death in boys ages one to four.[3] If there is any resuscitative effort conducted after the patient is rescued from drowning, outcomes are poor. One study looked at a group of children who received CPR by EMS providers; nearly half died immediately. Less than 15 percent had “good” recoveries, although that included some with mild neurological impairment.[4]
However, “miraculous” recoveries of children after drowning in very cold water have been reported. Although it’s been difficult for researchers to definitively say whether icy water makes a difference in outcome[5], both scientific journals and public media have reported several incidents where prolonged resuscitative efforts have resulted in positive outcomes for children who suffer from cold water drowning.[6, 7]
Pathophysiology
It’s not entirely clear what the mechanism might be that protects children better than adults in cold water drowning. The mammalian diving reflex has been cited as a possible explanation.[8] Mammals such as whales and dolphins initiate two distinct responses when diving deep into cold water: a parasympathetic response that dramatically slows heart rate (bradycardia), and a compensatory sympathetic response of massive peripheral vasoconstriction, shunting blood to key organs such as the heart and brain.
Coupled with adaptations that promote better oxygen storing capacity, receptors specially tuned to temperature and pressure changes, and behaviors that conserve oxygen consumption, mammals that spend all of their lives in water are able to feed in a much broader environment.[9] It is thought that perhaps all mammals posses this reflex. However, this has not been clearly demonstrated in humans.
Certain physiologic differences between children and adults might help promote a diving reflex. With more relative surface area and less developed thermoregulatory control of body temperature, children tend to cool much more quickly than adults.[10, 11] The result is that a child that falls into very cold water may be able to preserve oxygen stores within the blood and tissues much longer than adults.
How cold the body gets may also play a factor. A small pediatric study showed that that a core temperature of between 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit) was correlated to better neurologic outcomes.[12]
Treatment
The adage of “You’re not dead until you’re warm and dead” applies to pediatric cold water drowning victims. As this news story suggests, prolonged resuscitation should be aggressively performed, even when efforts appear futile.
Remember that rescuer safety is paramount. If you are not equipped or trained to perform water rescue, do not do so. You may very well become a victim yourself.
Once the child has been pulled from the water, determine if there are any signs of a pulse or breathing. It may be very difficult to detect a faint pulse through cold tissue; if there is any doubt, begin high quality chest compressions. Maintain adequate rate and depth of compressions, and rotate rescuers every two minutes.
Simultaneously, remove any wet clothing and wrap the child in dry blankets to prevent any further cooling. Move the patient carefully; sudden or rough movements may precipitate ventricular fibrillation.
According to American Heart Association guidelines[13], medical procedures should be minimal. A defibrillation shock can be attempted once, if the patient is in ventricular fibrillation. Establish intravenous access and insert an advanced airway as soon as feasible. Withhold any medication intervention normally associated with cardiac arrest, as there is little data to support its effectiveness in the hypothermic body.
The traditional treatment of adding warming packs to the patient’s skin may not be indicated, as to preserve the protective value of the hypothermic state.[14] Core rewarming using invasive procedures can be carefully monitored and controlled, allowing the patient to remain in a moderately hypothermic state while the brain recovers.
References
1. Center for Disease Control and Prevention. Unintentional Drowning Deaths in the United States, 1999–2010.
2. Nasrullah M, Muazzam S: Drowning Mortality in the United States, 1999–2006. J Community Health 2011, 36:69-75.
3. CDC.
4. Bell TS, Ellenberg L, McComb JG: Neuropsychological outcome after severe pediatric near-drowning. Neurosurgery 1985, 17:604-608.
5. Stathis Avramidis and Ronald Butterly. Drowning Survival in Icy Water: A Review. International Journal of Aquatic Research and Education, 2008, 2, 355-362.
6. EMS1.com. “‘Record’ 101 minutes of CPR saves toddler after icy drowning.” http://www.ems1.com/community-awareness/articles/2138285-Record-101-minutes-of-CPR-saves-toddler-after-icy-drowning/. Retrieved 18 March 2015.
7. Pearn, J. Medical aspects of drowning in children. Annals of the Academy of Medicine, Singapore. 21:433–435.
8. Sarnaik, A.P., & Vohra, M.P. (1986). Near-drowning: Fresh, salt, and cold water immersion. Clinics in Sports Medicine. 5:33–46.
9. Panneton, WM. The Mammalian Diving Response: An Enigmatic Reflex to Preserve Life? Physiology, 2013: 28 (5); 284-297.
10. Sloan, REG., & Keatinge, WR. Cooling rates of young people swimming in cold water. Journal of Applied Physiology. 1973; 35, 371–375.
11. Suominen, P.K., Korpela, R.E., Silfvast, T.G., & Olkkola, K.T. Does water temperature affect outcome of nearly drowned children. Resuscitation. 1997; 35: 111–115.
12. Wollenek, G et al. Cold water submersion and cardiac arrest in treatment of severe hypothermia with cardiopulmonary bypass. Resuscitation. 2002; 52 (3): 256-263.
13. American Heart Association. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science. Part 12: Cardiac Arrest in Special Situations Circulation. 2010; 122: S829-S861
14. Cantwell GP. Drowning treatment and management. Medscape. http://emedicine.medscape.com/article/772753-treatment Retrieved 19 March 2015.
