By: Grant Laidlaw of ACRA
We look at how to safely operate (and avoid any injuries) within the refrigerated environment inside a cold room and/or freezer.
When it comes to avoiding issues of hypothermia in particular, it’s important that staff attend a first aid course that specifically deals with hypothermia. In addition, the compulsory, legislated ‘Safe handling of refrigerants’ course should be completed by each staff member working with refrigerants. This course includes aspects of hypothermia.
Having said that, let us look into this subject, including the basic first aid aspects.
Risks of exposure
What are the health effects of exposure to cold and wet conditions found in cold room and freezer room environments?
Cooling of body parts may result in various cold injuries – non-freezing injuries and freezing injuries – and hypothermia, which is the most serious. Non-freezing cold injuries include chilblains, immersion foot and trench foot. Frost-nip and frostbite are freezing injuries.
Toes, fingers, ears and nose are at greatest risk because these areas do not have major muscles that produce heat. In addition, the body will preserve heat by favouring the internal organs and therefore reduce the flow of blood to the extremities under cold conditions.
Hands and feet tend to get cold more quickly than the torso because: they lose heat more rapidly since they have a higher surface area-to-volume ratio; and they are more likely to be in contact with colder surfaces than other parts of the body.
If the eyes are not protected with goggles in high wind chill conditions, the corneas may freeze. The most severe cold injury is hypothermia, which occurs from excessive loss of body heat and the consequent lowering of the inner core temperature (internal temperature of the body). Hypothermia can be fatal.
Immersion foot: When working in a cold room without the correct waterproof footwear, you stand the chance of developing immersion foot. Immersion foot occurs in individuals whose feet have been wet, but not freezing cold, for days or weeks. It can occur at temperatures up to 10°C. The primary injury is to nerve and muscle tissue. Symptoms include tingling and numbness, itching, pain, swelling of the legs, feet or hands, and even blisters. The skin may be red initially and turn to blue or purple as the injury progresses. In severe cases, gangrene may develop.
Trench foot: This is ‘wet, cold disease’ resulting from prolonged exposure to a damp or wet environment from above the freezing point to about 10°C. Depending on the temperature, an onset of symptoms may range from several hours to many days, but the average is three days. Trench foot is more likely to occur at lower temperatures whereas an immersion foot is more likely to occur at higher temperatures and longer exposure times. A similar condition of the hands can occur if a person wears wet gloves for a prolonged period under cold conditions described above. Symptoms are similar to immersion foot.
Examples of ‘freezing’ injuries
Frost-nip is the mildest form of a freezing cold injury. It occurs when ear lobes, noses, cheeks, fingers or toes are exposed to the cold and the top layers of the skin freeze. The skin of the affected area turns white and it may feel numb. The top layer of skin feels hard, but the deeper tissue still feels normal (soft).
Frost-nip can be prevented by wearing warm clothing and footwear. It is treated by gentle re-warming (such as holding the affected tissue next to unaffected skin of the victim or of another person). As for all cold-induced injuries, never rub the affected parts, becauseice crystals in the tissue could cause damage if the skin is rubbed. Do not use hot objects such as hot water bottles to re-warm the area or person.
Frostbite is a common injury caused by exposure to extreme cold or by contact with extremely cold objects (especially those made of metal). It may also occur in normal temperatures from contact with cooled or compressed gases. Frostbite occurs when tissue temperature falls below the freezing point (0°C), or when blood flow is obstructed. Blood vessels may be severely and permanently damaged and blood circulation may stop in the affected tissue. In mild cases, the symptoms include inflammation of the skin in patches accompanied by slight pain. In severe cases, there could be tissue damage without pain, or there could be burning or prickling sensations resulting in blisters. Frostbitten skin is highly susceptible to infection and gangrene (local death of soft tissues due to loss of blood supply) may develop.
First aid for frostbite, as well as immersion or trench foot, includes:
- If possible, move the victim to a warm area.
- Gently loosen or remove constricting clothing or jewellery that may restrict circulation.
- Loosely cover the affected area with a sterile dressing. Place some gauze between fingers and toes to absorb moisture and prevent them from sticking together.
- Quickly transport the victim to an emergency care facility.
- DO NOT attempt to re-warm the affected area on site (but do try to stop the area from becoming any colder). Without the proper facilities, tissue that has been warmed may refreeze and cause more damage.
- DO NOT rub area or apply dry heat.
- DO NOT allow the victim to drink alcohol or smoke.
- Seek medical attention.
Hypothermia
In moderately cold environments, the body’s core temperature does not usually fall more than 1°C to 2°C below the normal 37°C because of the body’s ability to adapt. However, in intense cold without adequate clothing, the body is unable to compensate for the heat loss and the core temperature starts to fall. The sensation of cold followed by pain in exposed parts of the body is one of the first signs of mild hypothermia.
As the temperature continues to drop, or as the exposure time increases, the feeling of cold and pain starts to diminish because of increasing numbness (loss of sensation). If pain cannot be felt, serious injury can occur without the victim noticing it. Next, muscular weakness and drowsiness are experienced. This condition is called hypothermia and usually occurs when the body temperature falls below 33°C. Additional symptoms of hypothermia include interruption of shivering, diminished consciousness and dilated pupils. When the body temperature reaches 27°C, coma (profound unconsciousness) sets in. Heart activity stops around 20°C and the brain stops functioning around 17°C.
Hypothermia is a medical emergency. At the first sign, find medical help immediately. The survival of the victim depends on their co-worker’s ability to recognise the symptoms of hypothermia. The victim is generally not able to notice his or her own condition.
First aid for hypothermia includes the following steps:
- Seek medical help immediately. Hypothermia is a medical emergency.
- Ensure that wet clothing is removed.
- Place the victim between blankets (or towels, newspaper, etc.) so the body temperature can rise gradually. Body-to-body contact can help warm the victim’s temperature slowly. Be sure to cover the person’s head.
- Give warm, sweet (caffeine-free, non-alcoholic) drinks unless the victim is rapidly losing consciousness, unconscious or convulsing.
- Transport the victim to an emergency medical facility.
- Do not attempt to re-warm the victim on a site (do not use hot water bottles or electric blankets).
- Perform CPR (cardiopulmonary resuscitation) if the victim stops breathing. Continue to provide CPR until medical help is available. The body slows when it is very cold and, in some cases, hypothermia victims that appear ‘dead’ can be successfully resuscitated.
All of this is of course preventable. Correct personal protective equipment (PPE) is a must and, in this instance, includes the use of a good quality thermal suit.
References
- SARACCA
- Pressure vessel regulations
- ACRA