With winter rolling in, it is important that we keep our men and women protected, and informed about the cold weather hazards they may face. Officers must brave the elements to perform their duties, whether it may be extreme heat, or cold. Being informed is the first line of defense to prevent and treat cold weather injuries.
Heat loss and regulation.
The body temperature stays around 98.6 degrees using different mechanisms that sum up and create “thermoregulation”. The body has a very small range of tolerable temperatures before it begins to exhibit detrimental effects. Temperatures can very a few degrees depending on the time of day (Welchallyn, 2003). The human body uses mechanisms like sweating, to bring down body temperature, and shivering, to raise it.
First, we will look into the types of heat loss. There are four main types of heat loss: conduction, convection, radiation, and evaporation. Conductive heat loss occurs when heat is exchanged from you, to an object colder than you. Concrete and metal are very conductive, so remember to place something between the body and the ground. Convection has to deal more with the water and air. As a fluid or gas comes across the body, it pulls heat off and lowers the body temperature. Water is about 25 times more conductive than air, so ensure you remain dry. Remember that sweat is a mechanism the body uses to cool down, so excess sweating can be detrimental! Radiative heat loss occurs through infrared emission of temperature. Most body heat is lost through the head, so remember to wear a cap. Evaporative heat loss occurs from liquids like sweat converting to gas. Heat is lost through sweating and even breathing.
The human body attempts to regulate this heat loss by shivering. Shivering uses major muscle groups and warms the body. Metabolism is important as well, as biochemical reactions produce heat as a by-product. Ensure you are eating well so the body has enough glucose and other nutrients to burn and stay warm. Vessels also begin to constrict to prevent heat loss in the extremities and keep vital blood in the core and the brain. This makes dexterity difficult with cold hands and makes the extremities prone to cold injuries. Make sure you wear gloves and extra socks to protect your limbs from the cold.
Risk factors that may make a person more prone to cold weather injuries include:
1. Old and young age- Older people don’t have the same thermoregulatory effectiveness as a young adult. Their skin also has poor circulatory perfusion and elasticity, increasing the chance of frostbite and other injuries. Children may ignore the cold and have poor judgment. They also have a larger head, causing them to lose more heat.
2. Alcohol, tobacco and drug use- Alcohol is a major diuretic and dilates all the vessels but makes the person feel warm. Alcohol and drugs also impair judgment. Drugs can also include prescription medications. Some medications can cause dehydration, creating a loss of thermoregulation as a consequence. Smoking causes peripheral arterial disease and decreases the flow of blood to the extremities. PAD can severely compromise a limb over time. At one point 80% of all arm and leg amputations at Royal Free Hospital were from smokers (Baker, 2005).
3. Dehydration and not eating-The body needs to be adequately hydrated in order to prevent both heat and cold weather injuries. Dehydration will surely contribute to hypothermia. Ensure you consume at least 8 – 10 glasses of WATER every day. This does not mean drinking soft drinks, coffee, or tea. Those drinks have caffeine, which is a diuretic, and will dehydrate you. Eat three meals a day because your body will require 10% more calories if you are doing mild work in the cold. High carbohydrate foods will help.
4. Other factors-Mental disorders can impair judgment and so can other medical conditions. Fatigue will greatly increase the possibility of hypothermia. Identify previous cold weather injury personnel. Previous cold weather injuries are more likely to become a cold casualty again. Traumatically injured personnel are very likely to become hypothermic and should be kept warm at all costs. Allowing a trauma patient to become hypothermic greatly increases mortality rates.
Hypothermia can be prevented through proper education. It is important to educate the department about the winter hazards, especially if winter hits very hard in your location. A yearly refresher may also be warranted to ensure that the officers don’t forget important information, and stay current on their procedures.
A simple guideline that can be used for dressing for the winter weather is the acronym C-O-L-D.
Cover/clean- Cover all exposed skin to protect against the wind. Cover the head to limit the amount of heat loss. Wear clean clothes and if possible change socks when they get damp. Dirty clothes do not hold heat as effectively as clean clothes can.
Overheating/overexertion-Though at times it is impossible to avoid overexertion in the LE field, eat adequately to replenish your glucose reserves afterwards. Dress for the job. Do not be wearing excessively warm jackets if you will be running a long distance. Avoid sweating profusely and dress appropriately for the task at hand.
Layer-You can add and remove layers, but one bulky jacket can’t be taken off if you have nothing underneath. Layers will also trap more heat and allow you to adjust the level of heat you will need for the task at hand.
Dry- Stay dry at all costs. Choose insulating fabrics like wool and polypropylene. Carry an extra set of clothes and uniform in your vehicle in the event you get wet. You never know when you will have to apprehend someone in a puddle of water, or wade into a lake to pull someone out.
Shield yourself from the wind as well. Your top lay should be a windbreaker to stop the convective effects of wind chill. Ensure you are well rested and have a proper diet to deal with the winter effects. If you are sick, you need to greatly increase your water intake as well.
All cold injuries are avoidable. It is likely you will experience a person in some degree of cold weather distress this winter, so educate yourself and your department so you can properly respond. In part two, we will cover the various cold weather injuries and treatments.
A. Wojahn (2002) Gale Encyclopedia of Nursing and Allied Health. Dehydration. Retrieved from http://www.healthline.com/galecontent/dehydration-2
ASH (2005) Action on Smoking and Health. Smoking and Peripheral Arterial Disease. Retrieved from http://www.ash.org.uk/files/documents/ASH_190.pdf
R. Curtis (2012) Princeton University. Outdoor Action Guide to Cold Weather Injuries. Retrieved from http://www.princeton.edu/~oa/safety/hypocold.shtml
WelchAllyn (2003) Normal Body Temperature Ranges. Retrieved from http://www.welchallyn.com/documents/Thermometry/Electronic%20Thermometry/SureTemp%20690/normalbodytempchart_20070323_suretempplus.pdf