Diving safety knowledge: Do not dive when you have a severe cold

The requirements for learning to dive are good health and no contraindications:

1. Have had middle ear surgery or corneal surgery; 2. Have a history of lung injury, especially Those with spontaneous pneumothorax; 3. Severe pulmonary obstructive diseases, such as chronic emphysema or severe asthma; 4. Those with congenital diverticula or pulmonary vesicular disease in the alveoli; 5. Those with a history of epilepsy or cramps; 6. Those who frequently faint for unknown reasons; 7. Those who have coronary artery disease, such as angina pectoris or a history of myocardial infarction; 8. Those who have red blood cell lesions, such as sickle cell anemia; 9. Patients with insulin-dependent diabetes mellitus ;10. People with long-term alcoholism or drug addiction; 11. People with mental illness

People with the above problems cannot bear too much exercise or cannot adjust psychologically, and are prone to danger, so they are not suitable Diving, but you can learn to snorkel. In places with good visibility, snorkeling can also enjoy the gifts that the sea brings to you!

Can I dive if I have a cold?

Diving when you have a cold is not recommended. Unless you answer ‘YES’ to the following questions, it is best not to go into the water when you have a cold. If one nostril is blocked, can you easily breathe through the other nostril?

If you have just recovered from a cold, do you not need to twist your nose for at least two hours?

You are? Isn’t it easy to balance ear pressure on shore?

Is it at least one day before you have symptoms of fever and cold sweats?

If you just catch a cold, are you? No coughing for at least two hours?

If you are taking medication, will your next dose be at least two hours after the end of the dive?

If vision correction is required Divers, can this problem be solved?

Yes, you can choose to buy a mask with myopia lenses. But if you wear contact lenses, generally speaking, there is no problem with soft contact lenses, but their use is not recommended.

What is ear pressure balance?

Ear pressure balancing refers to the technique of making the pressure in the ear the same as the surrounding environmental pressure in a certain way. The most commonly used method is to pinch the nose and inflate. Pinch the nose from the nose bag of the mask to block the nostrils, and then gently exhale through the nose. At this time, you will feel that the eardrums are bulging outward and there is a "gurgling" feeling. "A sound.

In addition to pinching your nose and blowing air, you can also achieve ear pressure balance by swallowing saliva, yawning or swinging your jaw left and right

The six golden rules for ear pressure balance are What?

1. Start equalizing your ear pressure before diving!

2. After diving, do it every few meters to avoid discomfort!

3. Don’t wait until you feel uncomfortable (or painful) to remember to start doing it!

4. If the ear pressure cannot be raised, increase it a little and try again! Try filling the mask with water and then draining it! If you still can't equalize the ear pressure after all your efforts, give up the dive!

5. If you have a problem with ear pressure balance, try using a rappel rope with your feet downward and dive slowly.

6. Never hold your nose, inflate for too long or too hard! You may injure your cochlea and eardrum!

What should I do if I have earache or tinnitus after diving?

It may be that the ear is filled with water or the nose is choked with water. The drainage method is

1. Tilt your head to the side of the ear where the water is flowing, pull the earlobe hard, and use the leg on the same side to drain the ear. Perform a one-legged hop

2. Aim the palm of your hand at the ear canal, seal the ear tightly with your hand, and tilt your head to the left if water enters your left ear, and then quickly move your hand away

3. The water will be sucked out. Use a sterile cotton swab to put into the ear canal to suck out the water

What are the safety rules for divers?

1. Be in the best physical and mental condition

2. Have relatively strong swimming ability

3. Receive correct training guidance

4. Establish a diving plan and dive according to the plan

5. Be familiar with the diving area. When diving in an unfamiliar area, you should be led by someone who is familiar with the area

6 .Carry first aid supplies

7. Measure your own abilities (yourself and equipment)

8. Check the equipment and use it in good condition

9. Use Complete and necessary equipment

10. Spearguns should be regarded as dangerous instruments and must be used with caution

11. Never dive alone and do not act without your companions

12. Ear pressure must be equalized before you feel discomfort in the ear

13. Get out of the water and ashore as soon as possible when you are injured, tired or unwell

14. Pay attention to the depth and time, and move carefully and correctly Ascent

15. Snorkeling experience is a necessary condition for scuba diving

16. Observe the diving depth limit. Skilled people who use air diving should also try to avoid depths exceeding 30 meters (100 meters). feet), never exceed 39 meters

17. Understand and apply underwater communication methods

18. Scuba diving must maintain the breathing method of deep inhalation and slow exhalation

19. Pay attention to the diving sequence when repeating diving, avoid decompression diving, and do safe decompression

20. Clean air should be used when diving

21. High-pressure gas cylinders should be Have good maintenance and correct handling

22. The equipment must be maintained regularly. Cylinders should be visually inspected at least once a year and water pressure tested at least once every three years.

What? Is it decompression sickness?

Decompression sickness, also known as DecompressionSickness (DCS) in English, occurs when the diving depth exceeds 10 meters or working in a room pressurized to 2 absolute atmospheres for more than 50 minutes. After indoor work, due to improper decompression, the inert gas (such as nitrogen N2 or helium He) remaining in the joints or body tissues cannot be sent out of the body with the blood circulation and forms bubbles, causing body discomfort or acute disorders, which is called Decompression sickness or CaissonDisease.

What are the types of decompression sickness?

Decompression sickness can be divided into three types according to symptoms: decompression sickness type 1, decompression sickness type 2, and chronic decompression sickness.

Decompression sickness type 1 is mainly caused by inert gas forming bubbles and blocking the subcutaneous tissue, joints or muscles, causing severe pain in the joints and affecting the ability to perform. The main symptoms are: skin itching and tingling. , rash, joint and muscle pain.

Decompression sickness type 2 is mainly caused by gas bubbles filling the respiratory system, circulatory system or nervous system of the human body, causing severe impairment of body functions and causing shock and death. Its main symptoms are: dizziness, dizziness, Nausea, vomiting, tinnitus, dizziness, speech impairment, blurred vision, numbness of limbs, difficulty in coordination, chest tightness and chest pain, blindness, shock, and death.

Chronic decompression sickness refers to workers who have been exposed to abnormal air pressure for a long time, resulting in chronic damage to the central nervous system or body tissues due to improper decompression; its main symptoms are: inattention, Vision loss, memory loss, slow movement, and abnormal behavior. There is also dysbaric osteonecrosis (Dysbarcosteo-necrosis), which is a type of non-traumatic and non-infectious ischemic osteonecrosis. It usually occurs in the long bones of the limbs of professional divers or high-pressure chamber workers, especially the femur and humerus. .

How to deal with and prevent decompression sickness?

1. During the process of transporting the patient to the hospital, it is best to have the patient lie down, untie the restraints (such as a diving suit, etc.), and raise the feet about 20-30 cm to avoid air bubbles blocking the blood vessels or brain nervous system. and danger occurs.

2. Do not let the sick person drive by themselves to avoid danger due to sudden pain in muscles and joints.

3. Keep the patient sent to the hospital under normal pressure, and avoid transporting the patient at high altitudes by plane to avoid worsening of the patient's condition due to drastic changes in air pressure that may overwhelm the patient.

4. Use the oxygen equipment in the ambulance to relieve pain and relieve stress for patients.

Decompression sickness is not a disease that will definitely occur, nor is it a disease unique to diving professionals. It is very important to make preventive work and plans before each work. In addition to the preparation work, the knowledge and decompression procedures that should be done must also be confirmed again and again to ensure safety.

⑴ Strengthen the correct concepts and formal training for divers or abnormal pressure projects

⑵ Implement correct and reliable decompression procedures

⑶ Professional diving equipment and construction Maintenance and attention to appliances

⑷Regular health examinations and attention to personal diseases

Under what circumstances will cramps occur? How to deal with cramps?

Camps may occur if you are nervous, if the water is too cold, or if you stay in the water for too long. Preparatory activities before entering the water should be sufficient, and the time in the water should not be too long. Once cramps occur, don't panic. For example, if your toes are cramped, then immediately bend your legs and use force to pull the toes apart and straighten them; if your calves are cramped, use your hands to pull the top of the fins toward your body, and push your calves forward to release the contraction. Stretch and relax the muscles, and then gently rub the calf muscles with your hands; when your fingers cramp, make your hands into fists, and then open them forcefully, and so on.

How to deal with nausea and vomiting?

Go ashore quickly, and then press the Zhongwan and Neiguan points with your fingers. If there is a Rendan, you can also hold one in your mouth.

What should I do if my skin becomes itchy or has a rash after diving?

Mainly caused by skin allergies. Go ashore immediately and take a piece of astamine or chlorpheniramine, and you will feel better soon.

What should I do if I have a headache while diving?

The reasons may be insufficient blood supply caused by chronic rhinitis, choking on water, cold body, or temporary cerebral vasospasm. At this time, you should go ashore quickly, use your thumbs to massage the Baihui, Taiyang and Lieque points on the top of your head, then apply a hot towel on your head, and then drink a cup of hot water, and you will get better.

What should I do if my abdomen becomes bloated while diving?

Abdominal pain and bloating may occur just after eating or diving on an empty stomach. At this time, you should go ashore and lie on your back, press the Zhongwan, Shangwan or Zusanli with the tip of your big toe, take 3 to 5 ml of ten drops of water orally, and apply a hot towel on the abdomen.

How to deal with itchy eyes?

It may be caused by unclean water. Immediately after landing, rinse your eyes with clean light salt water, then use chloramphenicol or erythromycin eye drops. It is best to apply a hot compress before going to bed.

Air embolism (AGE, arterial gasembolism)

In addition to decompression sickness in recreational diving, air embolism is also one of the main causes of serious injuries to divers. According to the diving medical warning network DAN According to data from the Diversalert Network, 58% of patients with air embolism experienced severe symptoms of pain within two minutes after surfacing after diving (1994, DAN).

The main cause of air embolism is improper holding of breath during the ascent of diving, which prevents the air from being discharged from the body. The lung tissue is overstretched and damaged, and the alveolar membrane ruptures, and air enters the blood circulation through the rupture. system, blocking the coronary arteries or brain capillaries, causing shock, "spasm", arrhythmia, loss of consciousness, and death in severe cases.

Causes of headaches after diving

Hypoxia

Hypoxia is the inability of human organ and tissue cells to obtain enough from the inhaled gas to maintain their normal functions. Caused by oxygen. Everyone's tolerance to hypoxia and symptoms vary greatly.

The reasons for hypoxia during diving are:

1. When diving ascends, the partial pressure of oxygen decreases and is insufficient to supply the amount of oxygen needed by the diver, causing hypoxia.

2. Divers hold their breath intermittently to save air consumption. Although I was doing the breathing method of inhaling deeply and exhaling slowly, the pause between inhaling and exhaling was too long (there was no continuous inhaling and exhaling).

3. In cold waters or intense exercise that increases the amount of work, the oxygen consumption increases, but the oxygen supply of the cylinder does not increase accordingly, resulting in insufficient oxygen.

4. The second stage falls off, the air supply system fails, and the air supply pipeline fails or breaks.

5. 1. The second stage gas valve is faulty, resulting in abnormal gas output. The gas flow in the gas supply system is insufficient, interrupted or exhausted. (Due to different brands, the pressure in the first stage is about 8~12bar, and the pressure around the second stage is 1bar)

6. The oxygen concentration in the supply gas is too low (less than 21%). Caused by incorrect gas mixture ratio of the air compressor.

1. Symptoms of rapid hypoxia include unconscious water coma, loss of consciousness, euphoria, overconfidence, apathy, etc.; after rising to the water, there are also symptoms of fatigue, headache, dizziness, amblyopia, etc. Phenomenon.

2. Slow hypoxia will cause symptoms such as poor coordination of movements in the water, poor operation, poor judgment, and weakened memory.

Carbon dioxide is highly toxic

The purity of carbon dioxide in air used for diving should not exceed 1000 ppm. The causes of carbon dioxide poisoning are:

1. Divers are afraid that the amount of air they breathe is insufficient, and they unconsciously prolong the time interval between each breath, interrupt breathing or hold their breath, thereby causing carbon dioxide accumulation.

2. The air compressor in the inflatable store does not have a carbon dioxide absorber, the carbon dioxide absorber is damp or has expired due to age, or the carbon dioxide filter (filter) system is faulty.

3. Almost all brands of underwater breathing apparatus (regulators) have problems with the elimination of carbon dioxide. Due to design flaws, part of the carbon dioxide in the exhaled gas is retained in the dead space of the breathing apparatus. , coupled with poor oxygen ventilation through masks or full or half-face diving helmets, causing the partial pressure of carbon dioxide to rise.

4. Too much dead space in the respirator can easily cause carbon dioxide accumulation to exceed the standard value.

5. Divers working in water or exercising excessively will cause the retention of carbon dioxide, increasing the risk of poisoning.

6. The air source used during inflation is polluted air (especially air compressors located in cities). If the air compressor is poorly maintained or uses the wrong oil or lubricant, it will produce waste gas. Here, If the environment is filled with air, many pollutants including carbon dioxide will enter the oxygen bottle. Breathing polluted air can cause headaches, nausea, and dizziness, but some are odorless and tasteless, which can cause potential unconsciousness to occur suddenly without warning.

The symptoms of carbon dioxide poisoning include:

Shortness of breath, excitement, fatigue, headache, dizziness, vomiting, confusion, loss of consciousness, coma, death, etc.

How to save yourself if you suddenly sink while swimming?

This danger is common among beginners or those with low swimming skills. During swimming, you will feel that your body suddenly loses strength and then your body sinks. This kind of situation is mainly caused by underestimation of one's own physical strength, uneven distribution of physical strength, excessive physical exertion, and oneself not aware of it. When encountering this situation, you must stay calm. You can close your breath when the body sinks, so that the lungs in the body can The body is filled with gas, and for a moment, the body will float up naturally. Then, stroke the small breaststroke hand (press down with the hand to stroke), kick the small breaststroke leg (mainly use the calf and ankle to draw a circle from the inside to the outside), and gradually transition to breaststroke. If there are auxiliary facilities such as water lines around you, you can rest for a while before swimming.

How to save yourself if you are entangled in aquatic plants in natural waters?

When swimming in wild natural waters, you must first observe the underwater environment. If you are unfortunate enough to be entangled in aquatic plants or fishing nets, you must remain calm and do not struggle. In this situation, only by staying calm can you have a chance of relief. The sooner an entanglement is discovered, the easier it is to free it. After being entangled, you should first relax your body, observe the entanglement situation, and find a way to free yourself. If you cannot free yourself, you can shout for help. (Aquatic plants and entangled rope tips will spread outward and upward as the body relaxes. As long as you carefully search for the source, you will be free)

When you or your diving buddy are in danger, how should you rescue each other? ?

Diver mutual rescue technology mainly refers to the corresponding first aid measures taken when two divers dive together and a certain respirator fails and the air supply is interrupted.

The steps are as follows: the two people face each other, with a distance of about 10cm; the person who supplies the air takes a full breath and hands the mouthpiece to the person who needs air; the person who needs air first exhales to drain the water in the mouthpiece , then take two breaths and then hand the mouthpiece to the air supplier, repeating this process while continuously rising out of the water

How to avoid bites from creatures in the water?

1. Practice perfect neutral buoyancy and avoid touching any living things

2. When diving, always pay attention to the things around you

3. When ascending or When diving, you should look up and pay attention to the environment above and around you. Pay special attention to areas where jellyfish may appear

4. Pay special attention when stepping into sand or mud, because it is very likely to be dangerous.

5. Avoid taking fish you have just hunted, and be especially careful if you are diving in an area where sharks may appear

6. Consider the area where dangerous creatures are located and try to avoid them

7. No matter how warm the water temperature is, wearing cold-proof clothing can protect our bodies from being harmed when in contact with other creatures

8. Avoid feeding or catching fish to avoid unnecessary Accidents

9. When taking photos, avoid using your hands to hold onto rocks to gain balance

10. Do not pick up shells

11. Determine the contents of the first aid kit It is suitable for rescue of diving injuries and to determine whether the medicine has expired

12. Learn the basic skills of rescue, including emergency treatment knowledge of biological injuries, etc. All people participating in water activities should learn CPR and first aid. Knowledge

How to avoid panic threatening you?

1. For divers who have not been in the water for a while, it will definitely help your confidence to practice basic movements in the swimming pool first.

2. What to do before diving Make a perfect plan, and follow your plan when diving

3. Discuss diving techniques with the instructor or divemaster

4. Try your best to discuss the issues you can think of with them in advance The instructor discussed and learned countermeasures

5. Never engage in diving activities that exceed your training or ability