scrubbers must not be allowed to overheat. In an attempt to replace carbon dioxide as a gaseous fire quenching agent, both nitrogen and helium have been considered and tested. It appears that neither of these inert gases is of value (except by the rapid dilution method in which the entire chamber atmosphere is rapidly diluted), as it is not possible to maintain a significant concentration of the gas in a given location. Due to their narcotic properties, more research is needed before the gases of heavier molecular weight can be considered for such use under pressure. Although dry chemical agents should provide rapid suppression of flame and excellent radiation shielding when initially discharged, the permanency of the fire extinguishment is doubtful. Although monobromotrifluromethane (CBrF3, "Freon" 1301) and chlorobromomethane ("Freon" 1011) have been shown to be effective extinguishing agents, a delayed application of the extinguishing agent could produce toxic pyrolysis products if the fire had a head start. High expansion foam has been shown to be an effective means of extinguishing fires that have been allowed to build up to their full intensity, but there is presently little knowledge as to the physiological safety of such agents due to pyrolysis products or otherwise. At the present "state of the art", due to safety. considerations, the best extinguishing agent for use in hyperbaric chambers is water. Water extinguishment operates primarily by cooling. It works best if it strikes the flame or wets the fire, but wetting most substances will retard to prevent their burning, even in oxygen. In spray form, although the fire may not be immediately put out, spread is halted and from this point on extinguishment is almost certain. The spray can be continued indefinitely, assuring safety of chamber occupants. Water at a spray density of 5 milliliters per sq cm per minute (14 gallons per sq ft per minute), applied for two minutes is required to extinguish cloth burning in 100 percent oxygen at atmospheric pressure. Water spray systems require special design for hyperbaric chamber applications. The pressure at the spray nozzles must be about 50 psi above chamber pressure to produce the desired degree of atomization and droplet velocities. Spray pattern of nozzles might be affected by chamber pressures. To compensate for the reduced coverage at elevated pressures, the design of the system must provide an adequate number of nozzles, and they must be strategically located, to wet all possible exposed areas within the chamber no matter what the chamber pressure may be. Pressurization is best obtained from a compressed gas source, since pumps have a startup time. Simultaneously with discharge of the water, all electrical power to the chamber should be discontinued to pre Mouth-to-Mouth head to the side for access to his mouth. The proper steps for administering mouth-to-mouth respiration are outlined below (See Figure 17-1). (1) Lay the victim on his back, and loosen any clothing that may have a restricting effect on his chest (wet suit, etc.). (2) Lift the neck so that the victim's head is tilted back, thus opening the air passage. Check the throat for any obstruction (tongue, false teeth. etc.) and remove same. It may be necessary to hold the victim's tongue out of his throat with the thumb of the hand holding his mouth open. (3) Open the victim's mouth, pulling the jaw upward toward the chest. Pinch off the nose with the other hand to prevent air leakage. (4) Place your mouth over the mouth of the victim (mouth and nose of a small child or infant), creating a seal. Blow into the victim until his chest rises. If air cannot be forced into the victim, his throat is still blocked and must be cleared prior to continuing. After exhaling into the victim, remove your mouth and let the air pass out of the victim's lungs. Continue this cycle at a rate of 10-12 times per minute for adults and approximately 20 times per minute for children. If the jaw is damaged or hopelessly blocked, resuscitation can be performed by sealing the victim's mouth and exhaling into the victim through his nose. A victim of drowning should also be examined for a heartbeat. If the victim's heart has stopped. closed-chest cardiac massages should be administered simultaneously with artificial respiration. 17.1.3.1 Emergency Tracheotomy In cases when a victim is dying of asphyxia and artificial respiration cannot be administered because of damage to the jaw or face or blockage of the windpipe, it may be necessary to perform a tracheotomy. WARNING This Operation Must Be Performed Only Ordinarily in an Emergency and Only by a Qualified Physician. The proper steps in performing an emergency tracheotomy are outlined below: 1. Place the victim's shoulders on a rolled towel or blanket, so the head is tilted sharply back. The skin will then be pulled tightly over the trachea. 2. Make a vertical incision along the centerline of the neck from the bottom of the Adam's apple to just above the suprasternal notch (can be felt approximately 1 inch below the Adam's apple), only as deep as the cartilage. 3. The windpipe or trachea will be directly below a layer of muscle. It is of a corrugated appearance, and lies directly in the midline. If it is not visible it may be felt. 4. Make an incision through the trachea (splitting its midline) large enough to pass a hollow tube when the walls are retracted. NOTE: This is a very dangerous procedure for an untrained person. 17.2 INJURIES AND INFECTIONS 17.2.1 Burns Burns are classified into three general categories according to severity. The least serious is the first degree burn, which is a reddening of the skin. With second degree burns, the skin will be blistered. The most serious is the third degree burn, in which the tissue is charred beyond repair. Burns can result from either heat or chemical action. Treatment The treatment that can be administered to a burn victim by other than a trained doctor is extremely limited. The burned area itself should be covered with a sterile dressing to exclude air. The victim may be given aspirin in minor burn cases to reduce the pain. To assist in replacing body fluids lost, the victim may be given liquids (except alcohol). All burns of more than a minor nature may be accompanied by shock, and the victim must be observed carefully. For all burns except minor reddening, the victim should be examined by a doctor. Burn ointment, grease, baking soda, or other substances must never be applied to serious burns. 17.2.1.1 Sunburn Sunburn is common to anyone who spends a great deal of time near the water. Avoiding prolonged, direct exposure to sunlight and wearing protective clothing is the best prevention. One of the most affected areas, and painful when burnt is the bridge of the nose. A covering of protective ointment helps prevent burning. Some of the most severe sunburns can be received on cloudy days when the sun is not visible and the individual may inadvertently permit excessive exposure. Sunburns can be painful, and can result in skin damage to a degree where the individual can no longer perform useful work. Symptoms Prickly sensation on back or neck Pain and tenderness to the touch Fever. Signs Extreme redness Fever blisters A tendency to avoid contact with affected area. Treatment A variety of sunburn ointments are commercially available which provide partial relief. If no special ointment is available, bandages soaked in tannic acid, boric acid, or vinegar will suffice. The victim should avoid further exposure until the condition has passed. Do not pop blisters or peel the flaky skin which accompanies sunburn or raw sore areas may result. 17.2.2 Fractures It is unusual for a diver to suffer a fracture while diving. The high density of water (compared to air) generally serves to slow motion and cushion blows so that a broken bone does not result. Divingrelated fractures usually occur on the surface. If a diver suffers a fracture while submerged he should immediately terminate the dive. Fractures can be classed into two general types. A closed fracture consists of a broken bone which has not penetrated the skin. In an open fracture, the broken bone is accompanied by an open wound, frequently with the bone sticking out. This type of wound is complicated by the chance of infection setting into the open wound. Signs Limb bent at unusual angle Area of fracture painful and tender In case of compound fracture, bone sticking out through wound. Treatment The only first aid required for closed fractures is to splint the affected limb. The limb should be immobilized with a splint. Flat pieces of wood, plastic, metal or any firm substance can be used. Inflatable splints are excellent. The splint serves to prevent movement and consequent complication of the injury. To prevent movement, the splint should be bound to the limb at a minimum of three places, at the wound, and above and below the fracture near the ends of the splint. When treating an open fracture do not try to move the limb to its natural position. Splint it to prevent movement, and cover the open wound with a sterile dressing. In open fractures, shock will probably be present and its symptoms must be anticipated. Regardless of the type of fracture, do not try to set the bone yourself. Let this be done by qualified medical personnel. 17.2.3 Wounds The diver is subject to a wide variety of wounds. The majority, such as coral wounds, wounds from sharp edges, or wrecks, etc., will be of a minor nature and require a minimum of first aid. However, there is always the chance of massive injuries such as might be incurred from a shark attack, barracuda or moray eel bite, or by being struck by a boat propeller. In the latter case, prompt, proper response is necessary to stop bleeding and prevent shock. 17.2.3.1 Minor Wounds Treatment for minor wounds consists of stopping the bleeding and cleaning the wound. Bleeding can be quickly stemmed by direct pressure, using either the hand, a pressure bandage or a combination of both (See Paragraph 17.1.1). If the wound is minor enough not to require medical attention, it should be thoroughly cleaned using fresh water and soap. If medical attention is required, such as minor stitches, the wound should be cleaned and covered with a sterile dressing, but no antiseptic applied. 17.2.3.2 Serious Wounds The major immediate concern with a major wound is to stop the bleeding and prevent the onset of shock. In case of serious wounds without amputation, control bleeding with a pressure dressing. In case of serious wounds with amputation, apply a tourni quet. Note the time the tourniquet was applied. Should a large chunk of flesh be missing, such as in a shark bite, it will be necessary to put a bandage or dressing directly in the wound. This will absorb blood and speed up coagulation. This bandage should be held tightly in place with another bandage placed directly over it. These steps should be effective in stopping the flow of blood. Once the bleeding is terminated, the victim must be treated for shock. Keep him calm, and lying down. If conscious and able to swallow, liquids can be administered (coffee, tea, waternever alcoholic beverages). Never attempt to give an unconscious victim liquids. Application of antiseptics, ointments, etc., are useless in major wounds and will slow the doctor's treatment as he may have to remove them before treatment. Qualified medical aid must be obtained in the quickest possible manner. 17.2.4 Dermatitis Divers who are continually exposed to salt water, especially in tropical climates and with no fresh water showers available, are subject to dermatitis (or skin disorders). If not properly cared for, it can spread over the entire body, incapacitating the individual. Small sore spots are bothersome and painful, and can be extremely hard to clear up. even with medication, if exposure to the conditions which caused them continues. Symptoms Red rashes Severe itching without visible cause Burning sensation while sweating. Signs Inflammation of affected area, blotchy complexion, welts Skin splitting or peeling Rashes Secretion of fluids. Treatment The best treatment is removal of the source of irritation. After each exposure the area should be washed with fresh water to remove salt, and thoroughly dried. Avoid wearing wet clothing, wet suits, etc., immediately after use, and if possible rinse diving gear off with fresh water. All affected areas should be cleaned, dried, and sprinkled with The best treatment for ear infection is prevention. The ears should be kept clean and dry, if possible. A common hair dryer is helpful. In addition, a good prophylactic program is highly desirable. A recent study (Thalmann 1974) recommends the following procedure: Irrigate each ear canal separately for 5 minutes with a 2 percent acetic acid in aluminum acetate solution (Domeboro Solution, Dome Laboratories) following each dive. Dry the outer ear canal with a towel after the solution has run out of the ear. To ensure the best results, this procedure should be carried out in a regimented manner after all dives, especially when under saturated conditions or in other situations where humidity is chronically high. The use of cotton swabs is not recommended, as they tend to irritate the ear canal and may perforate the drum. If an infection is contracted, consult a doctor for treatment. 17.2.6 Ruptured Eardrum Occasionally a diver will suffer from a ruptured eardrum. The cause of the rupture will be a pressure differential between the middle and outer ear. This can result from "chasing an object to the bottom," trying to descend (or rise) while not being able to clear the ears, or any situation where there is a rapid pressure change. Symptoms Severe pain on descent (or ascent) as rupture occurs Dizziness or nausea as water enters the middle ear Loss of hearing in affected ear Signs Bleeding from ear Redness and swelling of eardrum. Treatment No immediate treatment is necessary except a discontinuation of diving. See a doctor as soon as possible to prevent possible infection. The eardrum will heal in two to three weeks, and until it is healed, no diving should be attempted. 17.2.7 Electrocution Electrocution is generally the result of the careless handling of power equipment such as welding and cutting equipment, electric underwater lights, etc. All electrical equipment used under water should be well insulated. In addition the diver should take steps to insulate himself from any possible source of electrical current. When leaving the water to enter a boat or habitat, do not carry a connected light or electric tool. Signs Unconsciousness Cessation of breathing Heart failure Victim may not have been able to separate himself from the source of the shock. Treatment The first step in treatment is to secure the source of the shock. This is as much to protect the rescuer |