Rescue
Slide Show on Rescue vs. Recovery ~ by Dominique Evans-Bye
Slide Show on Drownings ~ by Dr. Tom Millington
Due to the time lag involved in the notification, response, and deployment of search and rescue divers following a drowning, it is rare that rescue is feasible. However, SAR divers must understand that it is not beyond the realm of possibility.
Drowning is the fourth leading cause of accidental death among the general population. The majority of drownings occur in fresh water: swimming pools, bath tubs, lakes, ponds, rivers, streams, etc. Unfortunately, many drownings result from the application of what has come to be known as the "deadly formula": hot weather + alcohol + cold water = drowning. Drowning is caused by an inhalation of water. Even though a victim may hold his breath, carbon dioxide build- up in the brain will eventually force an inhalation of water. Inhaled water is drawn from the lungs into the bloodstream causing the heart to arrest due to the excessive amount of water in the blood. Thus a drowning victim actually dies of a heart attack.
There are several stages which occur in a drowning:
1. Initially, the victim is surprised. He will attempt to keep his head above water, inhale deeply, and make downward movements with his arms.
2. The victim will eventually panic and may become hysterical. He will hyperventilate and struggle violently resulting in negative buoyancy.
3. Submergence occurs accompanied by reflex breath holding. As available oxygen is consumed from the air remaining in the lungs the urge to breathe becomes stronger.
4. After 2-3 minutes a combination of brain depression due to anoxia (severe oxygen deficiency) and the overwhelming urge to breathe caused by carbon dioxide build-up results in the victim breathing underwater. Although unconscious, in order to prevent the entrance of water into the lungs, the victim will reflexively swallow water which triggers retching and vomiting. As a result, most drowning victims will have a stomach full of water.
5. As available oxygen is consumed, the urge to breathe becomes even stronger. Unless a spasm of the larynx shuts off the flow of water into the lungs resulting in a "dry drowning", the victim will unconsciously take a strong deep breath resulting a filling of the lungs with water and more negative buoyancy.
6. Due to a lack of oxygen, brain function becomes more depressed and deprivation of oxygen to the heart results in cardiac arrest.
When effecting a rescue of a drowning victim, it is important to isolate the time that the victim was last seen breathing. Once submerged, the victim will begin to "breathe" underwater in about 3-4 minutes. After an additional 3-4 minutes, cardiac arrest occurs. Following cardiac arrest an additional 4-6 minutes will elapse before irreversible brain damage occurs. Thus the maximum time of submergence with a possibility of recovery is approximately fifteen minutes. However there are two important exceptions:
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A victim who has ingested alcohol prior to drowning will physiologically respond differently to the drowning as compared with the "sober" victim due to a depressed state of bodily functions brought on by the alcohol. This depression of vital body functions results in a poor chance of successful resuscitation.
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Due to a phenomenon of a primitive physiological response called the "Mammalian Diving Reflex" (which still exists in man), a spark of life is maintained and under the right conditions, a victim can be revived long after the fifteen minutes have elapsed. A victim of freshwater drowning has a good chance of recovery if the following factors are present:
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1. The drowning occurs in water below 70
degrees F. in temperature. (Throughout most
of the year, local water temperature is below
70 degrees F. (especially in deeper areas). -
2. The victim is recovered within one hour.
3. The victim is given CPR immediately upon
being brought to the surface (the protective
effect of the Mammalian Diving Reflex is lost
immediately upon removal of the victim from
the water). -
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4. The victim has not ingested alcohol.
5. The younger the victim, the better the chance
of recovery (the diving reflex is more
pronounced in children than in adults).
6. The clearer and cleaner the water, the better
the chance of recovery.
The best success of recovery involving the Mammalian Diving Reflex involves drownings which occur in cold, clear, freshwater. There is at present, only one incidence of saltwater drowning survival where the diving reflex was a factor. This incident involved a forty minute submersion in Alaskan waters.
It is critical that Search and Rescue Divers understand that a drowning victim recovered within one hour of submergence in water below 70 degrees F. must be immediately resuscitated (CPR) upon reaching the surface. Such a victim's chances for recovery are good. However, personnel must also realize that nothing is certain. A victim may be successfully resuscitated and later die due to excess fluids in the lungs (secondary drowning).
It is likewise critical that every resuscitated drowning victim be transported to a medical facility without delay.
Drownings
Prior to conducting a search for a drowning victim, any witness(es) should be interviewed to establish the last seen location of the victim in the water. Each witness should be taken separately to the exact spot (if possible) from where he last saw the victim and told to point out the location. Avoid asking the witness to estimate the distance and avoid also accepting any estimate of distance from a witness as such estimates over water are extremely difficult to judge and experience has shown them to be notoriously in error.
Once the witness has pointed out a location, divert his attention. Have him stand with his back toward the area he indicated or if necessary, remove him from the area while the interviewer solicits additional information from the witness. Out of view of the witness put a swimmer into the water (diver in free-diving gear) and have him swim to the location that the witness indicated. Do not allow the witness to watch the swimmer as it will affect his judgment with respect to the last location of the victim. With the swimmer in place, return the witness to where he indicated he was when he last viewed the victim. Confirm with the witness that the swimmer is in the exact location. If the witness wishes, allow him to relocate the swimmer. Once the location is confirmed have the swimmer mark the location, deploy divers, and commence the underwater search.
In still water, a drowned body will drop straight down. However, most bodies of water of any significant size will have some water movement which will tend to move the body along as it descends. In the ocean, where strong currents may exist, a drowning victim may be moved a considerable distance prior to reaching bottom. In moving water such as a river, the location of a body will depend on several factors: depth of water; the volume of moving water; velocity of the water; and bottom contour. In swift moving water, a body may be transported several miles.
Upon locating a submerged drowning victim, unless entangled, the searcher will invariably discover the body to be in the classic drowning position. Which is to say, in a jackknife position with buttocks high and head, arms and legs below trunk due to the absence of gas pockets in these areas of the body. Depending upon the relationship of the time of the "find" with respect to the time of drowning, the body may begin to re-float. A variety of factors will influence body re-float time including: depth; water temperature; type of water (fresh water, salt water, brackish water); organisms and wildlife in the water, clothing worn; any amount of air trapped in the victim's lungs; amount, type, and time of last food ingestion; any added weight; or mode of death (drowning vs. boating accident, etc.). In water warmer than 70 degrees F, a body may re-float in approximately one day; in water colder than 38 degrees F, a body many never resurface.
Some thought must be devoted to the method of recovery of the body prior to the actual find. The body can be placed into a body bag and buoyed to the surface (refer to the chapter on recovery and salvage), or alternatively the diver can swim the body on the surface for hoisting aboard a watercraft, or swim the body into shallow water for bagging. At any rate, the body should be placed into the body bag out of the view of onlookers, witnesses, and especially family members. Divers should then await the arrival of Coroner's officials prior to transporting the body to shore. It will be important for the coroner to know at what depth the body was found, the position of the body, any conditions which existed such as entanglements, etc. and any modifications which were performed to the body and/or its clothing during the recovery.
Scuba Deaths
The primary causes of scuba diving deaths are listed as follows:
1. Physical and/or psychological problems (cardiovascular problem, hypothermia, sea sickness etc.)
2. Environmental Condition (surf, cave, etc.)
3. Buddy system failure
4. Equipment difficulties (misuse of, lack of, lack of knowledge concerning, etc.)
5. Running out of air
6. Ascent difficulties
7. Entanglement
Upon locating the victim of a scuba diving accident, the searcher will most likely find the body to be face up. Unfortunately most divers are found with their weight belts on. The weight of the belt combined with that of the tank will cause the diver to come to rest on his back with his hands and feet floating up. Of course, this will not be the case in the event of entanglement nor when the diver is positively buoyant.
Prior to recovering the body of a deceased scuba diver, take time to make a mental inventory of the diver's equipment and it's condition:
1. Mask: In place? Flooded?
2. Fins: Both on?
3. Snorkel: Attached to mask?
4. Wet Suit: Fully suited? Condition?
5. Regulator: Reading of pressure gauge at depth?
6. Tank: Valve open? How much?
7. Weight belt: Belt on? Quick release inaccessible or jammed?
8. Other miscellaneous equipment: Speargun, goodie bag,
camera, etc.?9. Knife: Accessible?
10. Buoyancy Control Device: Properly worn?
Should you discover any necessary equipment to be missing, mark the body with a surface buoy and check the immediate area around the body. Chances are, any missing equipment will be located. Prior to recovery of the diver, turn off the air in the tank. Do not manipulate the diver's equipment in any other manner except as is necessary to facilitate recovery. (i.e.: removing weight belt) Send all equipment involved in a scuba death to the Coroner's office with the body.