Table of Contents

• Drowning
• Shallow Water Blackout
• Dry Drowning
• Near Drowning Treatment

Drowning

Drowning occurs when an individual is immersed in water and takes water into the lungs, subsequently not being able to breath. Drowning is divided into delayed drowning or secondary drowning, and immersion incidents. For Survive Outdoors, we are going to limit this to drowning and dry drowning incidents.

Approximately 140,000 deaths occur worldwide from drowning annually. There are approximately 9,000 deaths/year in the United States. This is second only to motor vehicle accidents. 64% of drowning victims are less than 30 years old, and 26% are less than 5 years old.

One interesting, and important note is that the proficiency at swimming is not related to drowning rates.

Gender differences need to be considered. White males have a greater incidence of drowning than white females. However white males have a greater ability to swim overall. Many individual do not die from drowning, but suffer from secondary effects such as hypothermia. For specifics of hypothermia, please see the hypothermia section on Survive Outdoors.

There is a large difference between freshwater aspiration and seawater aspiration. For more involved pathophysiology of the differences between freshwater and seawater aspiration, I would strongly advise you to seek other references, specifically Wilderness Medicine by Auerbach. In general, seawater aspiration has a higher mortality than freshwater. The reason for this is seawater has an osmolarity 4 times higher than that of the blood. When seawater is aspirated into the lungs, due to the high osmolarity, you get a transfer of plasma fluid directly into the small pockets of the lungs called alveoli and the lung parenchyma resulting in severe pulmonary edema, which is fluid in the lungs. For the general lay person, we need to think back to our biology classes in high school and cell membranes, and how chemicals like sodium and potassium cross membrane cell walls. That is what happens when you aspirate seawater, hence the severe reaction and higher mortality rate.

Shallow Water Blackout

Shallow water blackout is an event where an individual hyperventilates before they enter the water, common in endurance events and underwater swims. According to Dr. Auerbach, hyperventilation reduces the arterial carbon dioxide pressure without increasing oxygen storage. During swimming activity, the body then starts using stored oxygen in muscles before the classic carbon dioxide stimulus tells you to breathe, causing one to return to the surface to breathe. When this occurs, the victim usually blacks out and a drowning episode occurs. It is never advisable to hyperventilate before swimming. It increases your chances of causing greater harm than good. This author has frequently seen this occur in swimming pool scenarios, where teenagers are trying to compete in underwater swim contests such as who can swim the longest underwater. What appears to be a very harmless event can turn sour very quickly. Please refer to drowning and dry drowning for treatment.

Dry Drowning

The statistics vary, but somewhere between 15-20% of individuals who drown have what is called dry drowning. This is specifically a laryngospasm in response to water just starting to be taken into the lungs. It is a natural physiological mechanism for the larynx to spasm, stopping the water from entering the lungs. There is no evidence at this time to suggest that these individuals, since they do not have water in their lungs, would be better off treatment-wise, than others who do have water in their lungs, contrary to popular opinion. Treatment for these individuals remains the same as in a drowning incident, to get oxygenation to their lungs to get them to start breathing again.

Predicting outcomes in near drowning scenarios

In any medical emergency, it would be great to be able to predict the outcome. In many cases this cannot be done. It is not an exact science. However many researchers have been able to look at some prognostic factors through large sample populations. There are many factors that impact the outcomes in cases of near drowning. These include but are not limited to:

1. Age;
2. Length of submersion;
3. Length of time of being unconscious;
4. Water temperature;
5. Expedience of recovery and starting of treatment.

Near drowning victims who are alert, or at least have good pupillary reflex and are not in a coma should do well. Individuals who have been submerged greater than 10 minutes and have treatment resuscitation lasting longer than 25 minutes have usually less than a 5% chance of recovery.

In the journal of American College of Emergency Physicians, 1979. Orlowski lists unfavorable prognostic factors of individuals of near drowning as follows:

1. Age less than 3 years;
2. Estimates submersion time longer than 5 minutes;
3. No resuscitation attempt for at least 10 minutes after rescue;
4. Patient is in a coma on admission in the emergency dept.;
5. The have an arterial blood gas measurement of pH 7.1 or less.

Treatment for Near Drowning Victims

Outdoor treatment for near drowning victims
Administering CPR and assisting an individual in breathing are clearly the most important treatment interventions in victims of near drowning episodes. Mouth to mouth ventilation is still the treatment of choice in the outdoors. Attempting to perform cardiac compressions in the water is also a possibility, although very difficult to perform. In the last 30 years, this author has attempted to perform cardiac compressions on two occasions, one with success and one not.

There are really no available studies showing good circulation with cardiac compressions in the water. However the attempt should be made if there is cardiac arrest. Mouth to mouth ventilation should continue.

The following treatment discuss is based on having next to nothing on hand with you in an outdoor setting. Most individuals in the outdoors will not have float boards. However if one can improvise and has anything hard that can be placed on a victim’s back, this can be beneficial. This can be anything from a paddle to a boat seat that can be taken off and used in the water to help perform compressions. It is also helpful to have another individual with you. Once ashore, the individual should be laid in a supine position, with the head neither up nor down, parallel to the beach, as in a head up position, there is concern about intracranial pressure building. Respirator drainage and gastric drainage by pushing on the victim’s belly, or turning the victim over and perform the Heimlich maneuver have shown no great improvement in outcome. However if an individual has swallowed a large amount of water, and their stomach is distended, this can interfere with mouth to mouth ventilation, so it may be very beneficial in this situation to push on the stomach to expel water, turning the victim’s head sideways, or rolling the victim on his side, at which point ventilations would begin.

Regarding near drowning incidents, The American Heart Association advises against the Heimlich maneuver unless there is gross blockage.

Healthcare Provider: Medical Treatment
In-hospital management of asymptomatic victims of submersion incidents

1. Check the airway.
2. Supplemental oxygen, 12-15 liters/minute.
3. Pulse Oximetry and/or arterial blood gas.
4. Obtain a thorough history of the incident
5. Underlying causes, any history of epilepsy, drugs, heart attack, arrhythmias, or cerebral vascular accidents.
6. Take the vital signs every 10 minutes.
7. Draw bloods: CBC, complete metabolic panel, assess blood urea, nitrogen, platelets, PT and PTT.
8. Strongly consider a blood alcohol level and toxicology screen.
9. Observe all patients; they should be kept for at least 4-6 hours before discharge.

In-hospital management of symptomatic victims of submersion incidents

1. Check the airway.
2. Supplemental oxygen with a non-breathing mask, 12-15 liters/minute.
3. Consider endotracheal intubation for comatose patients and patients unable to maintain an oxygen level above 90 mm. of mercury on a high flow oxygen mask.
4. Check vital signs.
5. Start an intravenous line.
6. Draw blood for electrolytes, BUN, platelets, PT, PTT, arterial gas studies are imperative, urinalysis.
7. Administer bi-carb according to blood gas results.
8. Chest x-rays, cervical spine x-rays, if concerned about neck trauma.
9. Nasogastric tube and in-dwelling urinary catheter.
10. Admit all patients with abnormal vital signs and abnormal findings on blood values.

    References

    1. Paul S. Auerbach, Wilderness Medicine.
    2. Greenbaum, DM, et al., Continuous Positive Airway Pressure without Tracheal Intubation in Spontaneously-breathing patients, 1976.
    3. Ornato, JP: The Resuscitation of Near Drowning Victims, JAMA, 1986.
    4. Pearn, JH: Secondary Drowning in Children, British Medical Journal, 1980.
    5. Shelhamer, JH, Nathanson, C, Positive and Expiratory Pressure in Adults, JAMA, 1984.
    6. Fisher, B., Peterson, B., Hicks, G.: Use of Brain Stem Auditory-Evoked Response Testing to Assess Neurologic Outcome Following Near Drowning in Children. Critical Care Medicine, 1992.
    7. Gooden, BA: Why Some People Do Not Drown: Hypothermia vs. The Diving Response, Medical Journal of Australia, 1992.
    8. Kemp, AM, Sibert, JR: Outcome in Children Who Nearly Drown, British Isles Study, British Medical Journal, 1991.
    9. Schuman, Shuman, et al., The Iceberg Phenomenon of Near Drowning, Critical Care Medicine, 1976.