Drowning is death as caused by suffocation when a liquid causes interruption of the body's absorption of oxygen from the air leading to asphyxia. The primary cause of death is hypoxia and acidosis leading to cardiac arrest.
Near drowning is the survival of a drowning event involving unconsciousness or water inhalation and can lead to serious secondary complications, including death, after the event. Cases of near drowning are often given attention by medical professionals. Secondary drowning is death due to chemical or biological changes in the lungs after a near drowning incident.
In many countries, drowning is one of the leading causes of death for children under 14 years old. For example, in the United States, it is the second leading cause of death (after motor vehicle crashes) in children 14 and younger. Children have drowned in wading pools and even bath tubs. The rate of drowning in populations around the world varies widely according to their access to water, the climate and the national swimming culture. For example, typically the United Kingdom suffers 450 drownings per annum or 1 per 150,000 of population whereas the United States suffers 6,500 drownings or around 1 per 50,000 of population. Drowning related injuries are the fifth most likely cause of accidental death in the US. In some regions, drowning is the second most likely cause of injury and death for children after car accidents. The rate of near drowning incidents is unknown.
Victims are more likely to be male, young or adolescent, or black. Surveys indicate that 10% of children under 5 have experienced a situation with a high risk of drowning. The causes of drowning cases in the US are as follows:
Common conditions and risk factors that may lead to drowning include but are not limited to: (In no particular order)
People have drowned in as little as 30 mm of water lying face down, in one case in a wheel rut. Children have drowned in baths, buckets and toilets; inebriates or those under the influence of drugs have died in puddles. For a more detailed list of causes see swimming.
The reflex action is automatic and allows both a conscious and an unconscious person to survive longer without oxygen under water than in a comparable situation on dry land.
The breathing reflex in the human body is weakly related to the amount of oxygen in the blood but strongly related to the amount of carbon dioxide. During apnea, the oxygen in the body is used by the cells, and excreted as carbon dioxide. Thus, the level of oxygen in the blood decreases, and the level of carbon dioxide increases. Increasing carbon dioxide levels lead to a stronger and stronger breathing reflex, up to the breath-hold breakpoint, at which the victim can no longer voluntarily hold his or her breath. This typically occurs at an arterial partial pressure of carbon dioxide of 55 mm Hg, but may differ significantly from individual to individual and can be increased through training.
The breath-hold break point can be suppressed or delayed either intentionally or unintentionally. Hyperventilation before any dive, deep or shallow, flushes out carbon dioxide in the blood resulting in a dive commencing with an abnormally low carbon dioxide level; a potentially dangerous condition known as hypocapnia. The level of carbon dioxide in the blood after hyperventilation may then be insufficient to trigger the breathing reflex later in the dive and a blackout may occur without warning and before the diver feels any urgent need to breathe. This can occur at any depth and is common in distance breath-hold divers in swimming pools, refer to shallow water blackout for more detail. Hyperventilation is often used by both deep and distance free-divers to flush out carbon dioxide from the lungs to suppress the breathing reflex for longer. It is important not to mistake this for an attempt to increase the body's oxygen store. The body at rest is fully oxygenated by normal breathing and cannot take on any more. Breath holding in water should always be supervised by a second person, as by hyperventilating, one increases the risk of shallow water blackout because insufficient carbon dioxide levels in the blood fail to trigger the breathing reflex.
Freshwater can be more dangerous than saltwater in secondary drowning. When fresh water enters the lungs it is pulled into the pulmonary circulation via the alveoli because of the low capillary hydrostatic pressure and high colloid osmotic pressure. Consequently, the plasma is diluted and the hypotonic environment causes red blood cells to burst (hemolysis). The resulting elevation of plasma K+ level and depression of Na+ level, due to the hemolysis, alter the electrical activity of the heart. Ventricular fibrilation often occurs as a result of these electrolyte changes. Additionally, if drowning occurs in very cold water (<10o C), the uptake of cold water into the vascular system can stop the heart. In open heart surgery, the technique of pouring cold saline solution over the heart is used to prevent heart action. If the victim is resuscitated death can occur hours later due to renal failure. During hemolysis, hemoglobin is also released into the plasma which can accumulate in the kidneys leading to acute renal failure. In contrast, salt-water drowning does not lead to uptake of inspired water into the vascular system because it is isotonic to blood. Therefore, no red cell hemolysis occurs and the cause of death is asphyxia.
If a drowning occurs or a swimmer becomes missing, bystanders should immediately call for help. The lifeguard should be called if present. If not, emergency medical services and paramedics should be contacted as soon as possible.
The first step in rescuing a drowning victim is to ensure your own safety. Then bring the victim's mouth and nose above the water surface. For further treatment it is advisable to remove the victim from the water. Conscious victims may panic and thus hinder rescue efforts. Often, a victim will cling to the rescuer and try to pull himself out of the water, submerging the rescuer in the process. To avoid this, it is recommended that the rescuer approach the panicking victim with a buoyant object, or from behind, twisting the victim's arm on the back to restrict movement. If the victim pushes the rescuer under water, the rescuer should dive downwards to escape the victim.
Actively drowning victims do not usually call out for help simply because they lack the air to do so. It is necessary to breathe to yell. Human physiology does not allow the body to waste any air when starving for it. They rarely raise their hands out of the water. They use the surface of the water to push themselves up in an attempt to get their mouths out of the water. Lifting arms out of the water always pushes the head down. Head low in the water, occasionally bobbing up and down is another common sign of active drowning.
There can be splashing involved during drowning, usually a butterfly like stroke where the hands barely clear the waters surface, and sometimes victims can look like they are climbing an invisible ladder in the water.
Extenuating factors such as increased levels of stress, secondary injuries, and environmental factors can increase the likelihood of distress and/or drowning in persons who end up overboard. It is important that you recognize the behaviors associated with aquatic distress and drowning, so you can make informed decisions during emergencies.
Signs or behaviors associated with drowning or near-drowning:
After successfully approaching the victim, negatively buoyant objects such as a weight belt are removed. The priority is then to transport the victim to the water's edge in preparation for removal from the water. The victim is turned on his or her back. A secure grip is used to tow panicking victims from behind, with both rescuer and victim lying on their backs, and the rescuer swimming a breaststroke kick. A cooperative victim may be towed in a similar fashion held at the armpits, and the victim may assist with a breaststroke kick. An unconscious victim may be pulled in a similar fashion held at the chin and cheeks, ensuring that the mouth and nose is well above the water.
There is also the option of pushing a cooperative victim lying on his or her back with the rescuer swimming on his or her belly and pushing the feet of the victim, or both victim and rescuer lying on the belly, with the victim hanging from the shoulders of the rescuers. This has the advantage that the rescuer can use both arms and legs to swim breaststroke, but if the victim pushes his or her head above the water, the rescuer may get pushed down. This method is often used to retrieve tired swimmers. If the victim wears lifejacket, buoyancy compensator, or other flotation device that stabilizes his or her position with the face up, only one hand of the rescuer is needed to pull the victim, and the other hand may provide forward movement or may help in rescue breathing while swimming, using for example a snorkel.
Special care has to be taken for victims with suspected spinal injuries, and a back board (spinal board) may be needed for the rescue. In water, CPR is ineffective, and the goal should be to bring the victim to a stable ground quickly and then to start CPR.
If the approach to a stable ground includes the edge of a pool without steps or the edge of a boat, special techniques have been developed for moving the victim over the obstacle. For pools, the rescuer stands outside, holds the victim by his or her hands, with the victim's back to the edge. The rescuer then dips the victim into the water quickly to achieve an upward speed of the body, aiding with the lifting of the body over the edge. Lifting a victim over the side of a boat may require more than one person. Special techniques are also used by the coast guard and military for helicopter rescues.
After reaching dry ground, all victims should be referred to medical assistance, especially if unconscious or if even small amounts of water have entered the lungs. An unconscious victim may need artificial respiration or CPR.
The Heimlich maneuver is not recommended; the technique may have relevance in situations where airways are obstructed by solids but not fluids. Performing the manoeuver on drowning victims not only delays ventilation but may induce vomiting, which if aspirated will place the patient in a far worse situation. Moreover, the use of the Heimlich manoeuvre in any choking situation, involving solids or fluids, has become controversial and is generally no longer taught. For more information on this debate refer to the article Henry Heimlich.
100% oxygen is neither recommended nor discouraged. Treatment for hypothermia may also be necessary. Water in the stomach need not be removed, except in the case of paediatric drownings as a gastric distension can limit movement of the lungs. Other injuries should also be treated (see first aid). Victims that are alert, awake, and intact have nearly a 100% survival rate.
Drowning victims should be treated even if they have been submerged for a long time. The rule "no patient should be pronounced dead until warm and dead" applies. Children in particular have a good chance of survival in water up to 3 minutes, or 10 minutes in cold water (10 to 15 °C or 50 to 60 °F). Submersion in cold water can slow the metabolism drastically. There are rare but documented cases of survivable submersion for extreme lengths of time. In one case a child named Michelle Funk survived drowning after being submerged in cold water for 70 minutes. In another, an 18 year old man survived 38 minutes under water. This is known as cold water drowning.
The reduction of drowning through education and basic prevention steps, has become a necessity. Training information can be found through the following organizations Star Fish Aquatics, Jeff Ellis and Associates, through the local chapter of then American Red Cross and many other local organizations.
Training emphasises to help prevent drowning:
Common sense around the water to help prevent Drowning:
Emphasis may be needed in these areas to help prevent drowning:
In Europe, drowning was used -- more often than hanging, even -- as capital punishment, at least for a time. In fact, during the Middle Ages, a sentence of death was read using the words "cum fossa et furca," or "with drowning-pit and gallows." Commonly, women who were convicted of theft were drowned. Furthermore, drowning was used as a way to determine if a woman was a witch. The idea was that witches would float and the innocent would drown. For more details, see trial by drowning. It is understood that drowning was used as the least brutal form of execution, and was therefore reserved primarily for women, although favorable men were executed in this way as well.
Drowning survived as a method of execution in Europe until the 17th and 18th centuries. England had abolished the practice by 1623, Scotland by 1685, Switzerland in 1652, Austria in 1776, Iceland in 1777, and Russia by the beginning of the 1800s. France revived the practice during the French Revolution (1789–1799) and was carried out by Jean Baptiste Carrier at Nantes.