Environmental Emergencies: Hypothermia
February 5, 2019
Author: John Peckham
Congratulations! As you were checking your rig you looked out the window to see the biggest, coldest snowstorm you can remember. At the same time, your boss came in to say that you’ll have overtime to help cover storm-related absences. Baby, it’s cold outside; a shift not fit for man nor beast! Are you prepared?
Let’s talk about cold weather we might encounter and make sure we’re prepared to work in these potentially extreme conditions safely.
One of the first conditions we should be prepared for is hypothermia, which is when the core body temperature drops below 95º F. If you’re working in the cold, you already know that hypothermia is best prevented by preparing yourself to stay warm and dry when in the elements. Make sure you’re dressed in lightweight layers that will trap air and insulate but can be easily removed or replaced as needed. It’s good to start with a wicking inner-layer (Dri-FIT) to draw moisture away from the skin and finish with a breathable, water-resistant outer shell. Remember that fabrics like polypropylene, wool and silk retain heat when wet, and cotton gets COLD. Hats and gloves are a must. Consider a balaclava or other face protection too for the wind. Wind and wind chill can cause injury too!
Signs of Hypothermia
When folks are in the cold for prolonged periods and core temperature starts to drop, their blood vessels contract and peripheral blood flow is decreased as the body tries to keep the core heated (your hands and feet will start to feel cold). Many will also display what the National Institutes of Health call “The Umbles”:
- Stumbles – loss of control over movement, slowed motion, stiffness in extremities
- Mumbles – slurred, slowed, or incoherent speech, sleepiness or confusion
- Fumbles – slow reaction time, dropping objects, poor coordination
- Grumbles – change in behavior, expressing a negative attitude
As exposure continues and hypothermia progresses, you’ll notice your patient will demonstrate poor judgement and may appear detached or apathetic. Other physical signs can include cool, pale skin, shivering and increased pulse and respiratory rates.
As core temperature continues to drop, shivering can become more severe, which depletes energy reserves. Eventually, shivering will cease as the impulse can no longer be transmitted via the central nervous system. Muscles will then stiffen with the pulse slowing or becoming undetectable. Their skin will also become cold and cyanotic.
Our first management step for hypothermia is obvious: GET THE HYPOTHERMIC PERSON TO A WARM ENVIRONMENT. A good rule of thumb to remember is if the rig is too warm for you, it’s probably just right for your patient (similar to a severe burn trauma).
You’ll next need to get the person naked. Wet clothing draws heat away from the body very quickly, so getting the person into dry clothes or wrapped in blankets will help to slow heat loss. Assess the clothing for dampness, but it’s safe to assume it’s there.
As you continue to assess the patient, remember a rectal temperature is the only one that matters. Your pulse oximeter will likely be useless due to decreased peripheral circulation. Your ECG may reveal the presence of Osborn Waves (J-Waves), which occur when the epicardial potassium current increases relative to the current in the endocardium during ventricular repolarization (see image).
Check for cold-related skin injuries, including:
- Chillblains – itchy, red patches with swelling or blistering caused by the inflammation of small blood vessels in your skin after repeated exposure to cold
- Frostbite – exposed tissue freezes as peripheral circulation decreases or stops, resulting in injuries similar to thermal burns
It’s worth noting that not every hypothermia patient we encounter is going to be found outside, or even during a blizzard. A soaking wet person in temperatures as moderate as 50º F can develop hypothermia. An elderly person who’s fallen and been on the floor for a couple days before summoning help (remember: incontinent = damp… right over that femoral artery!) may also develop hypothermia. Perhaps your unit responded to a transient found unresponsive in a vacant house. How about a scuba diving emergency? As with so many other conditions, remember that the very young and the very old are always going to be more susceptible to heat loss.
Once we have our patient out of the cold and dried off, we’ll manage these folks in accordance with local protocols. If the patient can control their airway and maintains an acceptable level of consciousness (alert to person, place, time and purpose, and is able to perform simple math) treatment could include allowing warm, sweet fluids by mouth. Caffeine and alcohol should be avoided.
More to Watch For
Along with hypothermia, cold weather or the next “Storm of the Century” may bring other issues for you to deal with:
- Slips and Falls (musculoskeletal trauma)
- Falls through ice, immersion or drowning
- Carbon monoxide Incidents (generators and bad chimneys)
- Snow removal-related cardiac (Snow can be HEAVY!)
- Motor vehicle crashes (reduced visibility can lead to MANY CARS and increased risk to you!)
- Snow blower/thrower injuries
Winter is here. Be safe out there.