Scalding was caused by placing cloth strips dipped in 99°C boiling water on the skin of mice for 3 seconds, and then soaking the injury in tap water for 1 minute, resulting in only minor injury. Burns produced by dipping the cloth strips in 99°C boiling water for 10 seconds were given ice for 10 minutes, soaked in tap water for 1 minute and left untreated, resulting in moderate injury in the latter two and severe injury in the former.
After a mild or small burn, rinsing the burn area with flowing cold water or soaking the affected area in cold water for cold treatment is already almost common knowledge of first aid for burns. However, not everyone is very clear about how to implement the specific method, the temperature of the water used, and the duration of cold treatment.
On the other hand, some improper and wrong treatment is not only unhelpful but also harmful, even seriously harmful. For example, you cannot apply ice packs, use ice water for rinsing or soaking, and cold treatment is prohibited for large burns.
The correct cold treatment method
The history of cold treatment of burns can be traced back to the famous Roman physician Galen. However, it was only after the 1970s and 1980s that a series of scientific studies gave a more standardized approach and provided evidence for the scientific nature and benefits of this treatment.
However, in terms of specific implementation methods, the temperature of the water used and the cold treatment time cover a wide range. The temperature of the flowing tap water used ranged from 12 to 27°C, but it was also noted that ice water or water temperatures below 8°C could have adverse consequences. The time ranges from “several minutes”, “5 minutes”, “10 minutes”, until “the pain subsides”, or “until the ambulance arrives”, etc.
The recommendations of different countries and professional bodies are not exactly the same. For example, in the United Kingdom, it is recommended to use water at about 15°C for continuous flushing or soaking for no less than 20 minutes. The recommendation of the United States is to use flowing tap water to continuously rinse or soak for not less than 5 minutes. The joint recommendation of Australia and New Zealand is continuous rinsing with flowing tap water for 20 minutes; and the hint is to rinse with plenty of tap water, not wet towels, or fine stream rinsing or spraying, not to mention no treatment at all.
Although there is some variation in the specific methods recommended by the various recommendations, all recommend continuous rinsing or soaking with cold tap water for between 20 and 30 minutes. While most recommendations do not have the temperature of the water used that can be emphasized, all specifically emphasize, “no ice or ice water.”
Benefits of local cold treatment of burns
When we talk about burns, we usually refer to thermal burns of the skin that cause superficial skin damage while the heat continues to travel deeper causing further damage. It is obvious that cold treatment given as early as possible after removal of the heat source after a burn can end the injury and prevent further damage due to heat conduction.
However, how effective is this cold treatment and how long does it take to get the best results? A number of scientific studies have given extensive evidence.
For example, in a joint Australian and New Zealand experimental study, porcine partial-thickness contact burns were randomly treated with 5, 10, 20, and 30 minutes of flowing cold tap water rinses. It was found that after stopping the rinsing, the intradermal temperature increased by 1°C per minute in the 5- and 10-minute treatment groups, while it increased by 0.5°C per minute in the 20- and 30-minute treatment groups. For histopathological analysis performed on days 1 and 9 of the burn site, the 20- and 30-minute treatment groups were found to be significantly better than the 5- and 10-minute groups.
It was concluded that continuous local rinsing of the injury site with tap water for 20 minutes immediately after the onset of the burn would yield the best results in terminating thermal injury.
In addition, local cold treatment constricts local blood vessels, reduces exudation and edema, and decreases inflammation and pain. Also, it is self-evident that it provides a local cleansing effect.
Overall, the following benefits can be obtained by applying cold treatment to the area after a burn: 1) interruption of continued thermal damage; 2) pain relief; 3) reduction and prevention of edema; and 4) cleansing of the wound to prevent infection.
It should be noted that it is a folk custom to blow on the injury after a burn injury has occurred to relieve pain. In fact, the flowing air does have a certain cooling and pain-relieving effect, but this effect is very limited.
On the contrary, the blowing process inevitably spreads the bacteria in the mouth to the injury. The oral cavity contains a large number of bacteria, and one of the most important things to avoid in burns, but often difficult to avoid, is traumatic infection. Therefore, there are many guidance documents that specifically emphasize that this foolish act should be prohibited.
Why can’t I apply ice or use ice water?
With all the benefits of cold treatment, wouldn’t the lower the temperature be more beneficial? In fact, the use of ice packs or ice water rinses or immersions, instead of providing greater benefits, can exacerbate the damage.
And why is this? This needs to start from the regulation of skin blood circulation.
The human skin circulation is the main mechanism for regulating the body’s heat balance. The human skin blood vessels are controlled by a dual system of sympathetic vasoconstriction and vasodilation, which can produce powerful regulation.
At rest, the human skin blood flow is 200-250 ml/min. When subjected to cold stimulation, blood flow decreases rapidly, and vasoconstriction reaches its maximum at 15°C, where blood flow can be reduced to 20-50 ml/min. Local sustained hypothermic circulation can even stop completely and blood flow can reach 0. This is why bare hands and feet can appear pale when cold.
Below 15°C, vasoconstriction is interrupted by vasodilation that occurs 3-5 times per hour and lasts 5-10 minutes each time to avoid frostbite and necrosis of the tissue. Below 10°C, nerve deactivation occurs, resulting in numbness or even complete loss of skin sensation.
Continuous exposure to 0°C or below, such as ice packs or ice water rinses, initiates local adrenergic vasoconstriction mechanisms that are not innervated, and blood flow even stops completely. The small amount of blood flow to the skin that remains is thus insufficient to counteract the constant cold, and skin temperature drops at a rate of more than 0.5°C per minute until it reaches 0°C, where ice crystal formation and consequent cell and tissue necrosis occurs in the intra- and extracellular fluids.
Therefore, applying ice to the burn site or rinsing with ice water may cause localized frostbite and worsen the damage.
Experimental animal studies provide evidence for this presumption. A strip of cloth soaked in 99°C boiling water was placed on the skin of mice for 3 seconds to cause burns, and then the injury was soaked in tap water for 1 minute, resulting in only minor damage. Burns produced by dipping the cloth strips in 99°C boiling water for 10 seconds were given 10 minutes of ice, 1 minute of tap water immersion and no treatment, resulting in moderate injury in the latter two and severe injury in the former.
It can be seen that ice makes the burn site “worse” and causes more serious injury.
Why cold treatment is prohibited for large burns
For large burns, the prevention of shock is even more important than the care and treatment of burn wounds. Large burns mean that a large amount of blood leaks out of the body or into the tissue spaces, often leading to a rapid drop in blood volume and insufficient blood volume leading to the occurrence of shock. Shock leads to a total circulatory disorder in the body, which is even life-threatening in severe cases.
Cold treatment of burns, especially large burns, risks hypothermia on the one hand; on the other hand, it triggers vasoconstriction of large areas of the skin, squeezing more blood into the central circulation and leading to increased blood pressure. The combined effect of cold and elevated blood pressure on the brain and kidneys triggers massive diuresis and accelerates dehydration, which subsequently accelerates the onset of shock.
Therefore, for large injuries not only should the injury not be treated with cold, but should instead be kept warm.
How to distinguish between minor burns and major burns?
Usually, the criteria for mild burns that apply to cold treatment of wounds, based on a combination of burn area, degree of burn and general condition, are
In adults with partial thickness skin burns (which are usually referred to as first and second degree burns) with an area of <10% of the body surface area.
Partial thickness burns in children < 5% of the body surface area.
Full thickness burns of <1% of body surface area.
No comorbidities are present.
Burns exceeding the above criteria, or burns involving special areas such as hands, feet, face, groin, buttocks or large joints, the presence of respiratory burns, or burns combined with other injuries and complications, and those for which you are unsure of the extent of the burn, should be considered serious burns and should be taken to a doctor promptly.
Note: There are many ways to estimate the area of the burn, and the simplest way is the palm method, in which the area of the palm of the patient’s own fingers together is considered to be 1% of the body surface area for approximate estimation.