Divers need to know first aid measures to treat simple diving injuries and prevent them from becoming full-blown medical cases. Bleeding can be treated by applying pressure to the area of injury. Divers should maintain airway, breathing and circulation for those with head injuries.
On a recent trip, a friend injured his finger while climbing into the boat after a dive. He was standing on the bottom rung of the ladder. Ocean swells swung the ladder away from the boat, then back. My friend’s index finger was crushed between the boat and the ladder. His fingertip required first aid on the boat, then some further treatment once ashore. There was some concern for the skin flap covering the injury, since a loose flap will often lose the blood supply and die. This would require skin grafts and could complicate recovery. Since most of the dive group members were physicians, we had no problem cleaning the injury, holding the skin together with small butterfly adhesive strips and dressing the finger with clean bandages. The injury was well healed about four weeks later and no skin grafting was necessary. In this case, first aid preserved the skin in the crushed area and prevented a complicated surgical treatment later.
This event reminded me of the need to prepare for injuries and accidents while at a remote diving location. Knowledge of first aid is the key ingredient in preventing an injury from becoming a major medical event. In the following paragraphs, I have outlined some of the common diving injuries that should be dealt with using first aid. Simple measures at the scene of the injury will prevent serious complications from developing.
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Control of bleeding is essential to saving the life of an injured diver. We all have a fixed amount of blood (about 70 ml per kg of body weight or 5 quarts in a 155 pound person). Loss of a pint of donated blood (about 10 percent of the total blood volume) is not harmful; loss of more than 20 percent is. When a minor injury occurs, bleeding is usually from blood vessels in the skin but, in some cases, an artery or vein can be perforated. Pressure in the arteries averages about 100mm mercury (about 2 psi). This pressure will cause blood to spurt at a rapid rate from a punctured artery. Pressure in veins is about 7mm mercury (about 0.1 psi). This low pressure causes blood to flow slowly. If an artery is perforated, the blood is bright red and flows in spurts. If a vein is perforated, the blood is dark red and oozes rather than spurts.
Pressure in arteries and veins can be opposed by simple pressure on the wound, since neither pressure is very high. If a diver has a bleeding wound, take a clean cloth, towel, shirt, etc., fold it several times, place it over the wound and apply pressure. This simple measure will stop almost all bleeding. A tourniquet tied tightly around an arm or leg is not necessary, unless there is severe damage or an amputation. Since a forgotten tourniquet can cause loss of a limb, local pressure is the best choice in almost all injuries. Local pressure will not stop bleeding inside the body. Injuries severe enough to damage blood vessels in the chest or abdomen require rapid help from a surgeon.
Bone And Joint Injuries
These injuries include sprains, ligament tears and strains and bone fractures. In every case, the injury is owing to abnormal forces being imposed on the joint, bone, tendon or ligament. Motion of the structure will cause severe pain and the first priority is to immobilize the injured part. Preventing motion of a fracture site will often relieve pain without other measures. Immobilization can be accomplished by inflatable splints or splints assembled from boards, rolled newspaper, short poles (broom handle for example), etc. The splint should be placed alongside the injured limb and wrapped using cloth strips, tape, etc. An injured bone or joint will become swollen and painful if there is a serious injury; be sure a splint is wrapped snugly but not tightly. Swelling could turn the wrapping into a tourniquet.
If a bone is broken in the arm or leg, you should also consider the possibility of an artery injury. In both extremities there are large arteries that can be injured by a jagged bone end. If an artery is injured, it may not be able to carry blood down the extremity and the hand or foot may lose its circulation. Clues to lost circulation are a bluish skin color, severe burning pain in the hand or foot and absent pulses in the wrist or ankle. Such an injury requires rapid correction by a surgeon. The injured diver must be transported immediately to a medical facility for treatment.
Severe head injuries cause unconsciousness and the victim must be provided support while emergency transportation is arranged. First aid for an unconscious victim includes maintaining an adequate airway, assuring the victim is breathing and has a stable circulation (the ABCs of first aid). Rapid transportation to a hospital is the next highest priority. If there is bleeding, local pressure must be applied cautiously because of the risk of making a skull fracture worse. If there is evidence of a depression in the head, local pressure should be applied gently.
A severe head injury often means a neck injury or fracture. Because of the danger of damaging the spinal cord, extreme caution must be used when moving a victim with a serious head injury.
Careful splinting of the head and neck is essential. This is best done by carefully sliding the victim onto a flat board, where the head can be immobilized and held in a fixed position relative to the body. Once immobilization is accomplished, the victim can be moved safely. If the victim is injured in the water, immobilization can be done by floating the victim onto a board before lifting him/her out of the water. Head injuries always require urgent medical help but rushing the injured victim to a hospital can defeat the purpose of the rescue if the spinal cord is damaged during the move.
There has been an increasing problem with heart attacks in divers, because of the availability of dive training for, and the increased risk of heart attack in, older individuals. In many cases, the first manifestation of a heart attack is cardiac arrest and sudden death. Diving is a strenuous sport and people with heart disease can be subjected to the same stresses that cause sudden death while playing tennis or shoveling snow. Prevention and screening are important measures but, if a diver with heart disease (known or unknown) avoids the screening process, he/she may experience the first evidence of a heart problem while diving.
A diver with sudden, unexplained and continuing chest pain should be treated as a heart attack victim until medical help is obtained. This approach is necessary because of the high risk of death. If a diver becomes unresponsive with no explanation, you should rapidly assess the status of the circulation. The best means is by feeling for a pulse. If the pulse is absent, efforts at resuscitation (CPR) should be instituted. It is not possible to detail, in this article, the procedures for diagnosis and treatment of cardiac arrest. If you are a safe and conscientious diver, you should learn both first aid and CPR. The training will serve you well at all times and provide the knowledge needed to handle medical emergencies while diving. CPR training is covered in a basic life support course, which is usually provided by the local Red Cross or Heart Association.
Most marine injuries in sport divers involve stings from Fire Coral, jellyfish and other coelenterates. All of these stings have in common the deposition of nematocysts from the marine animal onto the bare skin of the diver. Prevention is the first line of defense and is accomplished by adequate skin coverings to prevent exposure. If you are stung by one of the coelenterates, you should apply vinegar to the area as soon as possible to destroy the remaining untriggered nematocysts.
The rash and other symptoms that follow the sting vary in intensity from mild to lethal. The most severe sting is from the Australian Box Jellyfish (Sea Wasp). This sting is often lethal. The diver must be supported immediately because the accompanying severe pain, respiratory arrest and shock will cause the victim to drown. Support of respiration and immediate transfer to a hospital is essential in a Sea Wasp sting. Most other coelenterate stings are not as severe and can be treated with medication for a few days until the toxin is broken down by the body.
There are many toxic animals that can cause harm. You should learn about the dangerous animals in your diving environment and how to identify them. Some important marine animals to know about include: Stonefish, Weaverfish, Scorpionfish, Lionfish, stingrays and cone shells. Stings from these can be dangerous. First aid includes immersing the wound in hot water, providing treatment for shock and respiratory support if needed. Note that most stingray attacks cause more injury than poisoning but both problems may require attention.
Diving Related Disorders
Air embolism and decompression sickness are the two important diving disorders that require first aid at the dive site. In all cases, the diver should be transported to a hyperbaric chamber for recompression therapy, even if symptoms are absent after the initial injury. Air embolism can be life threatening. First aid can include CPR if a cardiac arrest occurs and support of breathing in the unconscious diver. Immediate transfer to a chamber is essential to minimize permanent brain injury. Occasionally, an overpressure accident causes a pneumothorax or a collapsed lung. Although this problem is not usually fatal, there can be serious complications, including shock. Recognition is often difficult but the combination of shortness of breath and one-sided chest pain is helpful in diagnosis. Treatment may require the insertion of a needle into the chest to remove the trapped air. This is best done in a hospital.
Decompression sickness is usually less severe but requires treatment in a pressure chamber to avoid permanent injury. The target organ is often the spinal cord. The diver experiences loss of sensation, usually in the legs, paralysis or weakness of the legs or bowel or bladder paralysis. First aid includes warming the diver, providing fluids by mouth if the diver is conscious and an aspirin. One aspirin may reduce the severity of the spinal injury by preventing blood platelets from blocking blood vessels in the injured area. (The effectiveness of the aspirin in decompression sickness has never been proven but the harmful effects of one aspirin are minimal.)
It is not possible to provide a comprehensive discussion of first aid for divers in this article. It should be clear that first aid and CPR are necessary parts of diver training. Lacking first aid, an injury or poisoning can be fatal. In the diving environment, a little knowledge may save a life.
The Electric Man
A dive guide told me a story about an elderly man who hired him as a private guide for a day. The man told the guide he had recently been provided with an internal defibrillator. The man showed little concern over the device, said it was something like a pacemaker and proceeded to get ready for his dive. When he descended the ladder of the dive boat, he felt his heart begin to race and told the guide, who was in the water next to him, that he thought the defibrillator would fire. Within seconds the man jerked and the dive guide felt an electric shock. The device the man had implanted in his body is an internal cardioverter/defibrillator (ICD). It is used in people prone to sudden death from serious heart arrhythmias. Usually, the heart is damaged from previous heart attacks and this damage makes the heart prone to abnormal and sometimes lethal rhythms. The ICD senses the abnormal rhythm and shocks the heart in the same way a physician would shock the patient using an external device if a lethal rhythm developed.
Can this device shock another diver who is nearby? Consider the electric ray (torpedo ray), which is known to emit a strong electric field. The discharge is used to paralyze fish so the ray can capture and eat them. Studies on the electric ray indicate the discharge can reach up to 220 volts and produce about 4 watts of power. The discharge is provided in a series of 6 or 7 pulses of electricity, each lasting about 2/1,000 seconds. At 4 watts per pulse, total energy delivered would be about 36 joules in 6 pulses. The discharge lasts about 25/1,000 seconds(*) and is enough to stun a moderate sized fish or to shock a diver in bare skin who is nearby. There are many stories of divers being shocked by an electric ray, so the power is enough to be felt.
Now, let’s look at the ICD. This device produces 500 to 600 volts and can deliver 35 joules of energy. When it fires, it produces a single pulse of about 35 joules. The total energy is about the same as that of the torpedo ray! If a diver can be shocked by a torpedo ray, it is possible for a diver to be shocked by a nearby diver’s ICD.
This is an interesting observation but the shock is not enough to harm the accompanying diver. The more important concern is that someone prone to sudden death is diving at all. Since the risk of drowning is high if an abnormal rhythm occurs underwater I have advised other patients with ICDs to avoid diving. If you feel an electric shock while diving, hopefully it will come from an electric ray and not from a diver with an ICD.