Diver rescue - AbsoluteAstronomy.com

Diver rescue, following an accident, is the process of avoiding or limiting further exposure to diving hazards

Diving hazards and precautions

Divers face specific physical and health risks when they go underwater or use high pressure breathing gases. Some of these conditions also affect people who work in raised pressure environments out of water, e.g...

and bringing a SCUBA diver

Scuba diving

Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....

to safety. A safe place is often a place where the diver cannot drown, such as a boat

Dive boat

A dive boat is a boat that scuba divers use to reach a diving site which they could not reach by swimming from land.-Dive boat features:Features that make a boat suitable for use by divers are:* marine VHF radio* oxygen first aid* diving shot...

or dry land, from which professional medical treatment can be sought.

Reasons for needing rescue

There are many reasons that divers need rescue, including:

running out of breathing gas
Breathing gas
Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...
unconsciousness
Unconsciousness
Unconsciousness is the condition of being not conscious—in a mental state that involves complete or near-complete lack of responsiveness to people and other environmental stimuli. Being in a comatose state or coma is a type of unconsciousness. Fainting due to a drop in blood pressure and a...
being unable to see the depth gauge
Depth gauge
A depth gauge is a pressure gauge that displays the equivalent depth in water. It is a piece of diving equipment often used by SCUBA divers.Most modern diving depth gauges have an electronic mechanism and digital display. Older types used a mechanical mechanism and analogue display.A diver uses a...

or diving computer to make a safe ascent, generally because the diving mask
Diving mask
A diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. When the human eye is in direct contact with water as opposed to air, its normal environment, light entering the eye is refracted by a different angle and the eye is unable...

is lost, keeps flooding or is damaged
panic
Panic
Panic is a sudden sensation of fear which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety and frantic agitation consistent with an animalistic fight-or-flight reaction...
trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...

, diving disorder
Diving hazards and precautions
Divers face specific physical and health risks when they go underwater or use high pressure breathing gases. Some of these conditions also affect people who work in raised pressure environments out of water, e.g...

, medical condition
becoming lost or trapped underwater
Underwater
Underwater is a term describing the realm below the surface of water where the water exists in a natural feature such as an ocean, sea, lake, pond, or river. Three quarters of the planet Earth is covered by water...
being unable to return to the shore or a boat after a dive

Rescuers and training

In recreational diving

Recreational diving

Recreational diving or sport diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. In some diving circles, the term "recreational diving" is used in contradistinction to "technical diving", a more demanding aspect of the sport which requires greater levels...

, the urgency of the rescue and the remoteness of dive sites mean that professional rescuers rarely take part in diver rescues. Other divers at the scene become rescuers.

As the immediate in-water rescuer is often the diver's own buddy

Buddy system

The buddy system is a procedure in which two people, the "buddies", operate together as a single unit so that they are able to monitor and help each other.-Advantages:...

, diver training agencies often teach rescue techniques in intermediate-level diver training

Diver training

Diver training is the process of developing skills and building experience in the use of diving equipment and techniques so that the diver is able to dive safely and have fun....

courses; examples are the PADI

Padi

Padi or PADI may refer to:* Padi, Chennai, India* Padi , a musical group* Paddy field, a type of cultivated land * Professional Association of Diving Instructors, a scuba organization...

Rescue Diver, the BSAC Sport Diver and the DIRrebreather Rescue courses.

When the rescue involves a group of people, co-ordination is needed to make it quick and effective. This may be carried out by the skipper of the boat, if diving is taking place from a boat, or by a diver. Some training agencies offer courses to prepare divers for such as role, for example BSAC's Practical Rescue Management course.

Rescue activities

The effort and difficulty of a rescue varies widely and depends on many factors such as the nature of the problem, the underwater conditions and the type and depth of the dive site. A simple rescue could be to tow to safety a diver on the surface who is exhausted or suffering from leg cramp

Cramp

Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...

s. A complex and high-risk rescue would be to locate, free and bring to the surface a lost diver who is trapped underwater

Underwater

Underwater is a term describing the realm below the surface of water where the water exists in a natural feature such as an ocean, sea, lake, pond, or river. Three quarters of the planet Earth is covered by water...

in an enclosed space such as a shipwreck

Shipwreck

A shipwreck is what remains of a ship that has wrecked, either sunk or beached. Whatever the cause, a sunken ship or a wrecked ship is a physical example of the event: this explains why the two concepts are often overlapping in English....

or cave

Cave diving

Cave diving is a type of technical diving in which specialized equipment is used to enable the exploration of caves which are at least partially filled with water. In the United Kingdom it is an extension of the more common sport of caving, and in the United States an extension of the more common...

with limited breathing gas

Breathing gas

Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...

supplies.

The sequence of potential activities needed in a generic rescue are:

if the casualty's position underwater in unknown, locate the casualty and, if possible, mark the position
if the casualty is trapped, free the casualty
if the casualty is low on breathing gas
Breathing gas
Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...

, provide more gas
if the casualty is submerged, bring the casualty to the surface
if the casualty is not buoyant at the surface, make the casualty buoyant
if the casualty is not breathing, carry out continuous artificial respiration
Artificial respiration
Artificial respiration is the act of assisting or stimulating respiration, a metabolic process referring to the overall exchange of gases in the body by pulmonary ventilation, external respiration, and internal respiration...

on the surface
if help at the surface is available but not at hand, attract help
if the casualty is on the surface in the water and no help is available, tow the casualty to a boat or to land
if the casualty is beside a boat or the shore, remove the casualty from the water
if necessary, resuscitate, provide first aid and arrange transport to professional medical help

Locating the casualty underwater

It may be difficult to locate the diver underwater

Underwater

where dives take place in low visibility conditions, in currents or in enclosed spaces such as cave

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

s and shipwreck

Shipwreck

s or where the diver uses breathing equipment which releases few bubbles, such as a rebreather

Rebreather

A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...

. Even when open circuit equipment is used it may be difficult to see the bubbles due to surface conditions of wind, waves and spray, fog, or darkness.

Diver often use distance line

Distance line

A distance line, penetration line or guideline is an item of diving equipment used by SCUBA divers as a means of returning to a safe starting point in conditions of low visibility, water currents or where pilotage is difficult...

s, surface marker buoy

Surface Marker Buoy

A surface marker buoy, SMB or simply a blob is an inflatable buoy used by scuba divers, with a line, to indicate the diver's position to their surface safety boat while the diver is underwater.- Standard buoy :...

s, diving shot

Diving shot

thumb|right|Diagram of a diving shot upcurrent of a dive siteA diving shot is an item of diving equipment consisting of a weight, a line and a buoy. The weight is dropped on the dive site. The line connects the weight and the buoy and is used by divers to move between the surface and the dive site...

s, lightstick

Lightstick

A glow stick is a single-use translucent plastic tube containing isolated substances which when combined make light through a chemical reaction-induced chemiluminescence which does not require an electrical power source...

s and strobe light

Strobe light

A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope...

s to indicate their position to their surface support team. A standard precaution when entering enclosed spaces is to use a distance line; this marks the exit route, which may be needed after the diver's fins, wash, and bubbles dislodge silt

Silt

Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...

and loose overhead materials such as rust

Rust

Rust is a general term for a series of iron oxides. In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture...

which can reduce visibility to near zero.

Common search techniques such as the circular search or jackstay search, need preparation and practise if they are to be used effectively and safely. The spiral box search and compass grid search require less preparation, but probably greater skill.

Searches of enclosed spaces expose the rescuer to danger. The rescuers may need training and experience in Cave diving

Cave diving

or Wreck diving

Wreck diving

Wreck diving is a type of recreational diving where shipwrecks are explored. Although most wreck dive sites are at shipwrecks, there is an increasing trend to scuttle retired ships to create artificial reef sites...

to minimise the risks of that type of rescue.

Freeing the trapped casualty

Divers may become trapped in fishing net

Fishing net

A fishing net or fishnet is a net that is used for fishing. Fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and...

s; monofilament is almost invisible underwater. Rope

Rope

A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

s also are a threat to the diver's safety; normal diving equipment

Diving equipment

Diving equipment is equipment used by underwater divers for the purpose of facilitating diving activities. This may be equipment primarily intended for this purpose, or equipment intended for other puprposes which is found to be suitable for diving use....

has many inaccessible snag points that can trap the diver. Another problem occurs when divers try to squeeze through small gaps where their bulky equipment become wedged or caught. Also, old ferrous

Ferrous

Ferrous , in chemistry, indicates a divalent iron compound , as opposed to ferric, which indicates a trivalent iron compound ....

shipwrecks can be structurally unstable; they often retain their shape and therefore have components or cargos that have high potential energy

Potential energy

In physics, potential energy is the energy stored in a body or in a system due to its position in a force field or due to its configuration. The SI unit of measure for energy and work is the Joule...

due to gravity, but which have lost their strength through corrosion

Corrosion

Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...

.

Divers routinely carry a knife

Knife

A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

, line cutter or scissors

Scissors

Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin...

or shears to free themselves from ropes, lines and nets. Lifting bag

Lifting bag

A lifting bag is an item of diving equipment consisting of a robust and air-tight bag with straps, which is used to lift heavy objects underwater by means of the bag's buoyancy...

s can be used to help move heavy objects underwater.

Providing emergency gas

Running out of gas is a major cause for diving accidents.

The main reasons for running out of gas are:

failing to monitor consumption of the gas - not watching the contents pressure gauge
under-estimating the amount of gas needed for the ascent and decompression stops
consuming gas faster than estimated by going too deep, over-exercising or psychological stress
equipment failure, such as a frozen first stage or blown o-ring, in the main breathing set leading to escape of gas

Even when the prime cause of an underwater emergency is not running out of gas, lack of gas can easily become another problem for the rescuers to overcome because more gas is consumed during the accident and its aftermath. This is could be due to the diver remaining at depth for longer than planned or due to increases in the diver's breathing rate, due to exercising or panic

Panic

Panic is a sudden sensation of fear which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety and frantic agitation consistent with an animalistic fight-or-flight reaction...

.

Common configurations of diving cylinders and diving regulators used for as a backup or reserve for emergencies include:

an independent set - a complete, backup set such as a "pony" or one half of a “twinset” worn by a diver or a separate set brought down by the rescuer
an "octopus" - a second, backup demand valve or mouthpiece
Mouthpiece (scuba)
In breathing sets, a mouthpiece is a part that the user grips in his mouth, to make a watertight seal between the breathing set and his mouth. It is composed of a short flattened-oval tube that goes in between the lips, with on its free end a flange that fits between the lips and the tooth and gums...

on a scuba set that is already being used by the diver
a "spare air" - a small independent set with integrated regulator and mouthpiece

See the diving cylinder

Diving cylinder

A diving cylinder, scuba tank or diving tank is a gas cylinder used to store and transport high pressure breathing gas as a component of a scuba set. It provides gas to the scuba diver through the demand valve of a diving regulator....

and diving regulator

Diving regulator

A diving regulator is a pressure regulator used in scuba or surface supplied diving equipment that reduces pressurized breathing gas to ambient pressure and delivers it to the diver. The gas may be air or one of a variety of specially blended breathing gases...

articles for more details of the configurations.

There are two main ways of delivering the gas to the out-of-air diver; provide the casualty with a normal demand valve, preferably on a long hose, or "buddy breathing", the more risky of the two, where the two divers share one mouthpiece.

The gas capacity of the cylinder is important. Divers breathing at depth consume more gas because the gas must be delivered to them at ambient pressure. At the end of a deep dive they will need gas to breathe during the slow ascent to the surface and during any decompression stops.

The mixture of the breathing gas

Breathing gas

Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...

is important. Hyperoxic gases cannot be breathed safely below their maximum operating depth

Maximum operating depth

In technical diving and nitrox diving, the maximum operating depth of a breathing gas is the depth at which the partial pressure of oxygen of the gas mix exceeds a safe limit...

because of the risk of oxygen toxicity

Oxygen toxicity

Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at elevated partial pressures. It is also known as oxygen toxicity syndrome, oxygen intoxication, and oxygen poisoning...

and hypoxic gas cannot be breathed safely in shallow water because the partial pressure

Partial pressure

In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. The total pressure of a gas mixture is the sum of the partial pressures of each individual gas in the mixture....

of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

falls below that needed to sustain consciousness

Consciousness

Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

Bringing the casualty to the surface

If one of the divers is out of gas and is breathing gas from the rescuer, the rescuer and casualty must remain close to one another and ascend together. This ascent is complicated by the casualty's lack of gas to become buoyant at the start of the ascent and at the surface. At the start of the ascent the casualty needs to fin upwards and keep pace with the rescuer until, with the drop in ambient pressure, the gas inside buoyancy devices such as the buoyancy compensator or diving suit

Diving suit

A diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit typically also incorporates an air-supply .-History:...

, expands and provides buoyancy.

If the casualty is not capable of making an ascent, due to injury or unconsciousness, or the casualty cannot make a safe and controlled ascent, perhaps due to the loss or damage of the diving mask

Diving mask

A diving mask is an item of diving equipment that allows scuba divers, free-divers, and snorkelers to see clearly underwater. When the human eye is in direct contact with water as opposed to air, its normal environment, light entering the eye is refracted by a different angle and the eye is unable...

, the rescuer must control the casualty's ascent using the Controlled buoyant lift

Controlled buoyant lift

The controlled buoyant lift is an underwater diver rescue technique used by scuba divers to safely raise an incapacitated diver to the surface from depth. It is the primary technique for rescuing an underwater and unconscious diver...

. As the casualty is totally dependent on the rescuer, it is important if the two were to separate underwater the casualty should continue to ascend to the surface in a failsafe way.

The options, in order of desirability, for making the casualty buoyant include:

inflate the casualty's buoyancy compensator to lift off the seabed, then vent it to make a controlled ascent.
inflate the casualty's drysuit, if one is worn, to lift off the seabed, then vent it to make a controlled ascent. A drysuit is a less secure buoyancy device than a buoyancy compensator.
drop the weights casualty's diving weighting system
Diving weighting system
Divers wear weighting systems, weight belts or weights, generally made of lead, to counteract the buoyancy of other diving equipment, such as diving suits and aluminium diving cylinders...

. This may result in a dangerous and rapid ascent.
lift, by finning, the casualty into shallower water where gas in the casualty's buoyancy devices will expand, then vent it to make a controlled ascent.

If the casualty is not breathing, an urgent ascent directly to the surface is needed so that resuscitation can take place there. In this situation and if the rescuer needs to do decompression stops, the rescuer has a dilemma; take the casualty to the surface and increase the risk or severity of the bends, including irreversible injuries or death, or do the stops and kill the casualty.

Managing a convulsing casualty

Convulsions due to acute oxygen toxicity may render a diver unconscious. A common symptom is convulsions similar in appearance to epileptic seizure.

The US Navy Diving Manual Revision 6 Volume 4 section 17.11.1.4 recommends the following procedure for managing a convulsing casualty at depth. This differs significantly in some details from the procedure recommended by Dr E.D. Thalmann on the DAN website.

Assume a position behind the convulsing diver.
Only release the casualty's weights if progress to the surface is significantly impeded. (Thalman recommends releasing the weights unless the diver is wearing a dry suit, as the dry suit without weights may cause the surfaced diver to take a face down position on the surface.)
Do not ascend in the water until the convulsion subsides (Thalmann makes no recommendation to delay the ascent.)
Open the victim's airway and leave the mouthpiece in his mouth. If it is not in his mouth, do not attempt to replace it. However ensure that it is switched to "Surface" position in the case of a rebreather, so that the loop does not flood. (Thalman makes no mention of opening the airway, possibly on the assumption that air will escape without this manoeuvre.)
Grasp the victim round the chest above the UBA or between the UBA and his body. If this is difficult, use the best method possible to obtain control.
Ventilate the UBA with diluent to lower ppO2 and maintain depth until the convulsion subsides. (This step is significantly omitted by Thalmann.)
Make a controlled ascent to the first decompression stop, maintaining a slight pressure on the diver's chest to assist exhalation.
If the diver regains control, continue with appropriate decompression. (omitted by Thalmann)
If the diver remains incapacitated, surface at a moderate rate, establish an airway and treat for symptomatic decompression. (omitted by Thalmann)
If additional buoyancy is required, activate the victim's life jacket (inflate BC). The rescuer should not release his own weight belt or inflate his life jacket.
On reaching the surface, inflate the victim's life jacket if not already done.
Remove the victim's mouthpiece and (in the case of a rebreather) close the switch the valve to "surface" to prevent the rig from flooding and weighing down the victim.
Signal for emergency pickup. (Recreational divers may not have this option.)
Ensure the victim is breathing. Initiate rescue ventilation if necessary.
If an upward excursion occurred during the actual convulsion, transport to the nearest chamber and have the victim evaluated by an individual trained to recognize and treat diving-related illness.

Thalmann further comments that the decision whether to ascend with a diver who is convulsing is tricky, and cites the US Navy Diving Manual again, specifically:

If a diver convulses, the UBA should be vented immediately with a gas of lower oxygen content, if possible. (This is only appropriate with rebreathers, full-face masks with more than one gas supply connected, or with surface supply.)
If depth control is possible and gas supply is secure (helmet or full face mask), the diver's depth should be kept constant until the convulsion subsides.
If an ascent takes place it should be done as slowly as possible. (To some extent this is incompatible with the need to get the victim to a place where treatment is possible.)
If a diver surfaces unconscious because of an oxygen convulsion or to avoid drowning, the diver must be treated as if suffering from arterial gas embolism.

Thalmann further comments that a full face mask is desirable for use with high oxygen mixes, as it allows the diver to be kept at depth until the convulsion subsides, and that a diver who loses the mouthpiece must be surfaced as he will try to take a breath when the convulsion stops, and on open circuit, that as long as the diver has the mouthpiece in place and is breathing, it should be left until you can get him out of the water, but should be removed on the surface if rescue breathing is necessary and possible. Furthermore, the main goal while the diver is in the water is to prevent drowning and secondarily ensure that the airway is open after the convulsion stops by keeping the neck extended.

Making the casualty buoyant on the surface

Having reached the relative safety of the surface, it is important that the casualty does not accidentally re-descend. The usual methods of making the diver positively buoyant are to:

inflate the buoyancy compensator. This is a routine surfacing drill in some training schemes.
inflate the drysuit
Diving suit
A diving suit is a garment or device designed to protect a diver from the underwater environment. A diving suit typically also incorporates an air-supply .-History:...

, if one is being worn. The gas in a dry suit is not very secure; it can easily escape from seals
Seal (mechanical)
A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage , containing pressure, or excluding contamination...

and vents. Also, excess gas in the suit tends to make the legs buoyant causing the diver mobility problems.
drop weights
Diving weighting system
Divers wear weighting systems, weight belts or weights, generally made of lead, to counteract the buoyancy of other diving equipment, such as diving suits and aluminium diving cylinders...

.

Divers who are out of air will probably not be able to inflate their buoyancy compensator or drysuit using the normal and simple technique of pressing the direct feed injection valve. If their equipment allows it, they may be able to inflate these devices orally or use an integrated gas cylinder (if fitted).

Carrying out artificial ventilation in the water

If the casualty is not breathing, it possible to sustain respiration

Respiration (physiology)

'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...

or even restart it by artificial ventilation

Artificial respiration

Artificial respiration is the act of assisting or stimulating respiration, a metabolic process referring to the overall exchange of gases in the body by pulmonary ventilation, external respiration, and internal respiration...

(AV) at the surface of the water.

Methods of AV vary depending on diver training organization:

The BSAC technique works like this:

the casualty and rescuer are buoyant
the rescuer is positioned at the side of the casualty's head
Human head
In human anatomy, the head is the upper portion of the human body. It supports the face and is maintained by the skull, which itself encloses the brain.-Cultural importance:...

facing the ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
the rescuer extends the casualty's neck
Neck
The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The adjective signifying "of the neck" is cervical .-Boner anatomy: The cervical spine:The cervical portion of the human spine comprises seven boney...

and closes the mouth by lifting the chin with one hand
the rescuer pushes the casualty's far shoulder
Shoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

upwards with the other hand causing the head the twist towards the rescuer
the rescuer makes a seal over the casualty's nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

using the rescuer's mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

and exhales to fill the casualty's lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s
the rescuer aims to do 10 inflations per minute if stationary, 2 inflations every 15 seconds if towing

Attracting help

At this stage in the rescue immediate help is needed. Very often, the only people that can provide that help are nearby boat users and people on the shore. Unless the emergency services are very close by or the rescue is beyond the capability of the local rescuers, they will not be on the scene quick enough to be able to provide help. Often with a small group of rescuers the emergency services can only be contacted after the highest priority job of getting the casualty is out of the water has taken place.

Often the rescue can be quickened if a boat can come to the casualty rather than a rescuer having to tow the casualty to safety. Once at the surface, using many rescuers becomes feasible; they can communicate and co-operate to make the rescue more efficient.

Methods of attracting help include shouting, waving a straight arm, flag or surface marker buoy

Surface Marker Buoy

, blowing a whistle, flashing or swinging a torch/flashlight at night, or using a strobe at night. Cylinder powered, high-pressure gas whistles may be effective even over the sound of engines.

Towing the casualty

If the casualty is incapacitated or exhausted, help is needed to move the casualty to safety. Towing is time consuming and will exhaust the rescuer, especially in rough water, currents, or if the rescuer is wearing high-drag equipment such as a drysuit or carrying bulky equipment.

It may be possible to avoid a tow by using a boat to pick up the casualty and rescuer. Alternatively, ropes thrown to the rescuer can be used to pull the pair towards safety.

Removing the casualty from the water

Urgently lifting an injured or incapacitated casualty from the water is a significant problem especially where there are few rescuers, the sea is rough sea, the boat has high sides or the rescuers on the shore cannot get in or close to the water to help.

Rope

Rope

A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

s can be very useful, but some precautions are need:

avoid looping the rope so that it goes round the chest, preventing breathing, or the neck, causing asphyxia
Asphyxia
Asphyxia or asphyxiation is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs...

.
when near boats, keep the minimum rope in the water to prevent fouling propeller
Propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...

s
the minimum safe diameter is 12 mm, 1/2 inch. The rope should be doubled to increase the area of contact and reduce the lifting pressure on the casualty.

"Purbuckling" can be used to lift a casualty from the water up a 1.5 metre / 5 foot vertical surface such as a high sided boat, pontoon or a jetty. For a 1.5 metre lift, a length of rope of at least 4 metres / 13 feet is needed. The casualty is brought horizontally alongside. A rescuer in the water with the casualty takes the loop of rope under the casualty and passes it back to two rescuers on "land". The loop of rope is positioned so that in passes outside the arms between the shoulder

Shoulder

The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...

and elbow and around the outside of the legs between the knee

Knee

The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...

and the hip. The two rescuers on land secure the end of the loop that they control by standing heavily on it with one foot. They both pull on the central part of the loop rolling the casualty up the surface taking care to co-ordinate the tension

Tension (mechanics)

In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...

so that the casualty remains horizontal and that the rope remains in position on the casualty's arms and thightd. A rescuer should take care of that the casualty's head and neck is not damaged during the lift.

An alternative method of lifting the casualty using a rope is to pass the rope under an arm, around the back and under the other arm. The casualty is lifted vertically. There is a risk of spine damage by bending if the casualty is positioned with his or her back to the vertical surface and the rescuers pull the casualty's shoulders in board before lifting the lower end of the torso over top of the vertical surface.

Providing first aid

If the casualty is not breathing artificial respiration

Artificial respiration

must be provided continuously. It is more likely to succeed if it is started promptly. If the casualty is showing no signs of circulation

Circulatory system

The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

, chest compression

Cardiopulmonary resuscitation

Cardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...

are needed. See main article: cardiopulmonary resuscitation

Cardiopulmonary resuscitation

.

If the casualty has injuries the rescuers will need to provide first aid and prepare the casualty to be transported to professional medical help. See main article: first aid

First aid

First aid is the provision of initial care for an illness or injury. It is usually performed by non-expert, but trained personnel to a sick or injured person until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care...

.

In the developed world, transporting a diving casualty to hospital

Hospital

A hospital is a health care institution providing patient treatment by specialized staff and equipment. Hospitals often, but not always, provide for inpatient care or longer-term patient stays....

or a recompression chamber may be as simple as contacting the marine emergency services

Coast guard

A coast guard or coastguard is a national organization responsible for various services at sea. However the term implies widely different responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with...

, generally by using marine VHF radio

Marine VHF radio

Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz...

, telephone or a distress signal

Distress signal

A distress signal is an internationally recognized means for obtaining help. Distress signals take the form of or are commonly made by using radio signals, displaying a visually detected item or illumination, or making an audible sound, from a distance....

, and arranging a lifeboat

Lifeboat (rescue)

A rescue lifeboat is a boat rescue craft which is used to attend a vessel in distress, or its survivors, to rescue crewmen and passengers. It can be hand pulled, sail powered or powered by an engine...

or helicopter

Helicopter

A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

. If a diving injury such as decompression sickness

Decompression sickness

Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...

is suspected, the success of recompression therapy as well as a decrease in the number of recompression treatments required has been shown if first aid oxygen is given within four hours after surfacing. In other parts of the world and particularly in remote location, it may be difficult to quickly arrange reliable emergency medical transport and treatment; good insurance

Insurance

In law and economics, insurance is a form of risk management primarily used to hedge against the risk of a contingent, uncertain loss. Insurance is defined as the equitable transfer of the risk of a loss, from one entity to another, in exchange for payment. An insurer is a company selling the...

and self-reliance are needed. In-water recompression

In-water recompression

In-water recompression or underwater oxygen treatment is the emergency treatment of decompression sickness of sending the diver back underwater to allow the gas bubbles in the tissues, which are causing the symptoms, to resolve...

is a high-risk alternative that may be useful in locations where the casualty would not survive the journey to the nearest recompression chamber due to its distance.

Precautions during the rescue

Rescuers should not take unacceptable risks; any rescuers who become casualties themselves may jeopardise the rescue of the original casualty particularly as many of the emergency resources available at dive site, such as rescue manpower, first aid oxygen, underwater time and gas are generally in short supply.

Conscious casualties may panic and put the rescuer's safety at risk particularly when the rescuer approaches a casualty in or under the water. It may be possible to avoid contacting a panicked casualty by throwing a rope or buoyancy

Buoyancy

In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...

aid and encouraging the casualty to help him or herself. If contact must be made, the rescuer should try to approach the casualty from a direction that presents least risk to the rescuer, such as from behind. Alternatively, the rescuer may need to wait until the casualty is incapacitated before approaching.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.