Paradox in the Cold: Hypothermia’s Deceptive Signs

You’re deployed as part of a SWAT team on a prolonged operation in a densely forested area, as the Lead Tactical Medic. The temperature is a bitter 31°F, with continuous winds dropping the effective temperature to 19°F. The team has been operating for several hours. The setting sun brings darkness and even colder conditions. You are paired with a SWAT officer and positioned approximately 35 minutes from the staging and command area when your radio crackles:

"18-Zulu-1 to 18-Delta-1"

You speak into the waterproof throat microphone, "Go to 18-Delta-1."

"My partner seems to be acting unlike his typical jovial self. I could use your expertise in figuring out what is up with him."

"Roger that - break - Lead 18-Delta-1 and 18-Zulu-7 we clear to rendezvous with 18-Zulu-1 on a possible medical?" you ask of your team leader.

"Affirmative 18-Delta-1, provide an LCAN after your initial assessment," the team leader advises.

"LCAN upon assessment, 18-Delta-1 moving."

Understanding the high-risk nature of the operation, you secure your gear and crawl 75 feet to 18Z-1’s position, keeping tactical awareness at the forefront to ensure safety while responding to the medical issue. You are acutely aware that you are the only medic on this mission, supporting a team of 11 operators deployed in pursuit of a heavily armed escaped felon who has taken an ex-lover hostage in a very remote and large county park system. The stakes are high, and every decision you make could impact not just the patient, but the entire operation.

You find the operator, Kevin, leaning against a tree, visibly distressed, with gear and layers of clothing removed. Their partner, 18-Zulu-1, gestures toward them and says, “I think something’s wrong; they’ve been acting off for the last ten minutes.”

As you approach the operator, he says, “Bro, I am totally burning up. I feel like I have a fever and can’t seem to get cool, no matter how many tequilas I down.” His words are slurred, and his behavior seems erratic. As he speaks, he grabs a handful of snow from the ground, shoves it into his mouth, and chews it before swallowing hard. The snow consumption strikes you as unusual and potentially significant, suggesting he might be struggling with impaired judgment or desperation to regulate his body temperature.

Initial Assessment

You don’t have access to advanced monitoring tools like a BP cuff or pulse oximeter due to your stripped-down tactical loadout, so you rely on clinical assessment.

Here’s what you observe:

• The operator’s skin is pale, slightly clammy, and cool to the touch.

• They are visibly disoriented, struggling to follow your questions and instructions, but were able to swallow the snow.

• They complain about feeling hot and have removed layers of clothing despite the frigid temperatures.

• Intermittent shivering is present, but less intense than expected for the conditions and lack of clothing.

• Their speech is slightly slurred, and they appear fatigued.

Before continuing, pause and develop a differential diagnosis based on these observations.

What conditions could explain the operator’s symptoms?

Consider the following potential pathways:

Environmental Factors: Could prolonged exposure to cold temperatures and wind have caused hypothermia or another cold-related condition?

Metabolic Issues: Is there a possibility of hypoglycemia or dehydration exacerbating their confusion and fatigue?

Neurological Causes: Could a head injury or underlying condition like a stroke explain the slurred speech and disorientation?

Toxicological Concerns: Is there any chance of toxin exposure, such as ingestion or absorption of a harmful substance?

Share your thoughts on the most plausible differentials before proceeding to develop a plan of care. To assist you, here are a few potential differential diagnoses to consider based on the symptoms:

Hypothermia: The operator's paradoxical undressing, disorientation, and diminished shivering align with symptoms of hypothermia.

Hypoglycemia: Erratic behavior, slurred speech, and fatigue could indicate low blood sugar, especially if caloric intake has been minimal during the operation.

Toxin Exposure: Ingesting or encountering environmental toxins might explain the operator's confusion and unusual behavior.

Dehydration and Electrolyte Imbalance: Prolonged exertion in cold weather can exacerbate dehydration, leading to confusion and fatigue.

Neurological Event: A transient ischemic attack (TIA) or mild stroke should remain on the differential given the neurological symptoms.

Think critically about these possibilities and add your own based on the available information.

Now, develop a treatment plan for this operator. Remember, you cannot call for additional resources to assist with the evacuation or care of the patient; you must transport the operator to the staging area, on foot, approximately 35 minutes away.

As you formulate your plan, consider the following:

• Immediate Field Management

• Preparing for Patient Deterioration

• Evacuation Plan

• Radio Communication

• Team Considerations

• Threat Considerations

  
  

Outline your treatment and evacuation strategies while keeping the mission’s priorities and constraints in mind. Before proceeding, a word of caution: the next section reveals key answers and insights. Stop reading now if you prefer to develop your own plan first.

Real-World Case Review

In this Scenario Saturday I decided to present this case to Amber, one of my colleagues at Group Espada and Black Flag EMS, to see how they would handle this situation. What follows is my interview with Amber but fist a bit about her background.

Amber is a highly skilled Tactical Paramedic with extensive experience in high-risk environments. She serves as part of Black Flag EMS and Group Espada, specializing in austere medicine, tactical operations especially care under fire, and advanced prehospital care. As a Tactical Medic for a federal agency and a Flight Paramedic in Virginia, Amber delivers lifesaving interventions in dynamic, high-stakes scenarios. Known for her adaptability, critical thinking, and composure under pressure, Amber is a trusted leader in tactical EMS, balancing patient care with mission success.

What are you thinking about as you work to get to the operator and once you make contact?

Amber: The first thing I’d do is maintain tactical awareness. Crawling to their position, I’d ensure no immediate threats compromise our safety. As soon as I reach the operator, I’d assess their condition assuring they have an airway, are perfusing and try to gather details from their partner as to what transpired. Simply stated, rule out life threats exhibited by the patient but also assuring we are not tactically compromised. Based on their paradoxical undressing, disorientation, and shivering, I’d strongly suspect advanced hypothermia. I would then provide the LCAN update to the Team Leader and copy the command post.

Once you suspect advanced hypothermia, what’s your priority in treatment?

Amber: Stabilization is key. I wrap the operator in an emergency blanket and insulate them from the ground. Shielding them from the wind is just as important, and I’d use any resources available—tarps, jackets, or even body heat if necessary. To address potential hypoglycemia, I’d give them glucose gel or a high-calorie snack, ensuring they can swallow safely and not compromise their airway. The goal is to stop further heat loss while preparing for evacuation. It is also important to understand that with prolonged hypothermia the body has probably used calories to try to keep warm. So, despite their glucose levels, if they can safely swallow, they are getting calories to support fuel needs. We also need to keep in mind that most tactical operators have low body fat percentage, so their susceptibility to the cold is much higher than those with a higher BMI. Chances are they are also dehydrated but we cannot address that in our current situation.

Let’s talk about evacuation. This isn’t an easy situation—rough terrain, limited resources, and high risk of deterioration. What’s your strategy?

Amber: Evacuation must be deliberate. I’d enlist their partner and another operator and employ our people mover. My partner would be focused on threat management. Minimizing rough patient movement is critical to avoid triggering cardiac instability, such as ventricular fibrillation. Every step would be slow and calculated, with frequent stops to reassess their condition. The 35-minute trek requires constant vigilance. I suspect that given the tactical situation, possible fatigue of the operators, concern for triggering a cardiac issue in the patient, that 35-minute trek may turn into a 60-minute crawl if we are lucky.

Communication is vital in these situations. How would you keep command informed?

Amber: I’d provide a concise but thorough update to the team leader, detailing the operator’s condition, our evacuation plan, and any additional risks to the team. Our go to format, as you know is LCAN. I’d also recommend assessing the rest of the operators for early hypothermia signs and ensuring calorie intake and hydration. Clear communication ensures command can balance medical needs with mission priorities. I do suspect in this situation we would probably regroup as the team would be down at least four or five assets at this point.

Once you reach the staging area, what’s your immediate focus, especially without additional medical support and a possible delayed transport time?

Amber: At staging, I’d continue advanced rewarming by placing warm packs on major vessels, like the neck and armpits, groin cavities and avoiding the extremities to prevent after-drop. We would also get them out of their wet clothes and into a vehicle with temperature set on high. I’d prepare for critical complications, such as respiratory arrest or VFib. If the operator arrests, I’d initiate hypothermic cardiac arrest protocols, prioritizing continuous compressions and gentle handling until higher-level care is available.

After-drop, what is after-drop?

Amber: After-drop is a phenomenon that occurs during the rewarming process of a hypothermic patient. It happens when cold blood from the extremities returns to the core, causing a further drop in core body temperature. This occurs because rewarming the extremities too quickly can lead to peripheral vasodilation, which allows the colder peripheral blood to circulate centrally, potentially worsening the hypothermia.

In prolonged hypothermic situations, this is especially critical to consider. If you’re not careful, aggressive rewarming techniques like applying direct heat to the arms or legs can exacerbate the patient’s condition rather than improve it. After-drop increases the risk of cardiac instability, including arrhythmias like ventricular fibrillation, which could be fatal in someone already on the edge physiologically.

This is why, in the field, I focus on core rewarming—placing heat packs on areas like the neck, armpits, and groin, which are close to major blood vessels. This helps warm the core gradually while avoiding further destabilization. Ensuring the patient remains as still as possible is also vital because rough handling can trigger cardiac events. Managing after-drop is a delicate balance, but it’s essential for giving the patient the best chance of survival. To make it easy, we warm from the core outwards not from the limbs inward.

This all seems very BLS, is there a role for ALS in this scenario?

Amber: That’s a great question, and while a lot of the initial care for hypothermia may seem very BLS-focused, there’s absolutely a role for ALS protocols and tools in managing more advanced cases. Let me walk you through what I’d be doing.

First, I’d start by establishing IV access if I have the capability. Warmed IV fluids are incredibly important here—normal saline or lactated Ringer’s prewarmed to body temperature. These fluids not only help stabilize perfusion but also avoid the risk of worsening hypothermia, which can happen if cold fluids are introduced. It’s all about balancing hydration without overloading the patient, especially if they’ve been experiencing cold-induced diuresis.

Another priority would be cardiac monitoring. Hypothermia can cause bradycardia or even dangerous arrhythmias like atrial fibrillation or ventricular fibrillation (VFib). Having a monitor on the patient allows me to pick up on those changes early. If VFib occurs, I’d prepare for defibrillation, but I’d know that it may not be effective until the patient’s core temperature rises above 86°F (30°C). Until then, I’d focus on rewarming and supporting their stability.

Airway management is another consideration. If the patient shows signs of respiratory compromise, like hypoxia or slow, shallow breathing, I’d start oxygen therapy. Ideally, I’d use warmed and humidified oxygen to avoid cooling them further. If they deteriorate into respiratory arrest, advanced airway management would become a priority—likely intubation if the tools are available.

Medications are more limited in hypothermia care, but they can still be a part of the plan. For example, if I suspect hypoglycemia, I’d administer dextrose to help restore glucose levels. Pain management might also come into play, especially as rewarming can be rather uncomfortable. In that case, I’d consider fentanyl, using it carefully to avoid impacting their blood pressure too much or a ketamine cocktail to avoid depressing the respiratory centers.

Finally, I’d make sure all of this is done with an emphasis on gentle handling. Advanced hypothermia puts the heart at risk of arrhythmias, so I’d avoid unnecessary movement during IV placement or transport. It’s a delicate balance, but with the right tools and protocols, ALS can make a huge difference in supporting BLS efforts and addressing complications as they arise.

You mentioned warmed IV fluids - two quick questions - what if I don't have warmed fluids, would you risk giving non-warmed fluids and how non-warmed is not warm enough? Secondly, do we want to slowly raise the temperature of the patient or damn the torpedoes?

Amber: More great questions. Let’s tackle fluids first: if warmed fluids aren’t available, I’d avoid using room-temperature or cold fluids unless the patient is unstable from hypovolemia or shock. Non-warmed fluids can worsen hypothermia by lowering the core temperature further. Ideally, fluids should be at 98.6°F (37°C) or higher. If necessary, I’d improvise—using body heat to warm the bags or better yet put them near heating vents in a vehicle.

For rewarming, slow and steady wins. Rapid warming, especially of the extremities, risks after-drop—where cold blood returns from the periphery to the core, potentially causing arrhythmias or cardiac arrest. Instead, I’d prioritize core warming with heat packs on major vessels like the neck, armpits, and groin. Controlled rewarming avoids sudden temperature shifts and ensures the patient’s stability.

So no, no "damn the torpedoes" here. Hypothermia requires patience and methodical care to save a life without making things worse.

One of your specialties is austere medicine and prolonged tactical care - what are you thinking about in terms or predictive care for this patient if there is an extended transport time?

Amber: In a prolonged transport scenario, predictive care isn’t just about thinking ahead, it’s about actively preparing for what might happen. Whether you’re BLS or ALS, part of predictive care is staging your tools and resources so you’re ready to act immediately when the situation demands it.

For example, I’d have my airway kit prepped and within arm’s reach in case the patient goes into respiratory arrest. If I have oxygen, I’d ensure it’s set up and ready to go. My cardiac monitor, if available, would be attached, and I’d prepare for potential VFib by having the defibrillator pads placed but holding off on shocks until the patient’s core temperature rises enough for defibrillation to be effective. If I’m running an IV, I’d double-check the line to make sure it’s secure and delivering warmed fluids steadily.

It’s about minimizing delays—if the patient arrests or deteriorates, I don’t want to be fumbling through my bag looking for what I need. Everything should be positioned and ready to go because, in austere environments, every second counts. Predictive care is equal parts preparation and execution.

Any last words, thoughts or things you think we should share?

Amber: Yes, hypothermia can be deceptive—it often looks stable until it suddenly isn’t. That’s why it’s so critical to anticipate complications and stay one step ahead. Whether it’s preparing for respiratory arrest, cardiac instability, or even something as simple as keeping the patient insulated, everything you do should be deliberate and with purpose.

I’d also say this: hypothermia isn’t just about the patient in front of you. It’s a team issue. If one operator is affected, it’s likely others are close to the edge, even if they don’t realize it yet. Take the time to check in with everyone, ensure calorie and fluid intake, and enforce layering protocols. Prevention is always easier than treatment in these conditions.

Finally, remember that your composure sets the tone. Whether you’re BLS or ALS, the team looks to you for guidance. Confidence in your training, preparation, and decisions can mean the difference between a successful outcome and a preventable tragedy. Stay sharp, stay focused, and always be ready for the unexpected. That’s how you win in austere medicine.

Understanding Hypothermia: A Deep Dive

Hypothermia, the condition where the body’s core temperature drops below 95°F (35°C), is a silent threat that affects people of all ages and conditions. While the cold environment is the most obvious cause, hypothermia can develop in surprisingly mild temperatures, especially if someone is wet, exhausted, or exposed to wind. Let’s explore its stages, physiological impacts, and why it’s so deceptive.

The Stages of Hypothermia

1. Mild Hypothermia (95°F to 89.6°F / 35°C to 32°C):

Symptoms: Shivering (the body’s natural heat-generation response), rapid breathing, increased heart rate, fatigue, and mild confusion.

Physiological Response: The body prioritizes heat retention by constricting peripheral blood vessels, keeping warmth near vital organs. Energy expenditure increases, which can quickly deplete glucose stores.

2. Moderate Hypothermia (89.6°F to 82.4°F / 32°C to 28°C):

Symptoms: Shivering becomes less effective or stops entirely, mental confusion worsens, slurred speech develops, and coordination is impaired.

Physiological Response: Metabolism slows significantly. The heart becomes increasingly irritable, and the risk of arrhythmias, such as atrial fibrillation, begins to rise. Peripheral vasoconstriction continues, which contributes to cooling of the extremities.

3. Severe Hypothermia (Below 82.4°F / 28°C):

Symptoms: Loss of consciousness, weak or irregular pulse, shallow or absent breathing. The patient may appear clinically dead but can still recover with proper care.

Physiological Response: Core temperature regulation fails entirely. Enzymatic and cellular processes slow dramatically, leading to profound bradycardia and eventual cardiac arrest if untreated.

Paradoxical Undressing: A Critical Sign

Paradoxical undressing is one of the most deceptive phenomena associated with hypothermia. Patients experiencing moderate to severe hypothermia may suddenly strip off layers of clothing, despite being in freezing conditions. This occurs due to:

Peripheral Vasodilation: As hypothermia progresses, the body’s ability to maintain vasoconstriction begins to fail. Blood suddenly rushes back to the extremities, creating a sensation of intense warmth.

Neurological Confusion: The cold effects brain function, impairing judgment and leading to irrational behavior. The combination of these factors can trick patients into believing they are overheating, leading to undressing.

This phenomenon is dangerous because it accelerates heat loss, further reducing core temperature. For responders, paradoxical undressing is a red flag indicating advanced hypothermia.

Why Hypothermia Is Deceptive

Hypothermia progresses silently and can mimic other conditions, such as intoxication or stroke, making it easy to miss. Symptoms like slurred speech and confusion often overlap with other diagnoses, particularly in vulnerable populations like the elderly. The lack of dramatic outward signs early on leads many to underestimate its severity until it becomes critical.

Metabolic Challenges in Hypothermia

The body’s efforts to combat hypothermia create immense metabolic demands, particularly in the early stages when shivering is the primary heat-generating mechanism. Shivering can increase the metabolic rate by two to five times, rapidly depleting available glucose and glycogen stores. As hypothermia progresses, the body shifts from carbohydrate metabolism to fat and protein breakdown, further stressing energy reserves.

This caloric deficit has a direct impact on the brain. Glucose is the brain’s primary fuel, and a drop in glucose levels—whether from shivering, poor caloric intake, or prolonged exposure—leads to cognitive impairment, confusion, and slowed decision-making. In severe cases, hypoglycemia combined with hypothermia can cause profound neurological dysfunction, including unconsciousness.

For responders, maintaining the patient’s caloric intake is critical. Administering glucose or high-energy snacks can provide a quick boost, but prolonged hypothermia often requires more comprehensive management of energy stores and metabolism. Recognizing these metabolic challenges is key to preventing further deterioration and stabilizing the patient.

Population-Specific Considerations

Infants and Children:

Infants have a higher surface-area-to-volume ratio, making them lose heat rapidly. Their ability to shiver is limited, and they rely heavily on non-shivering thermogenesis via brown fat metabolism to generate heat.

Signs of hypothermia in infants include lethargy, weak crying, and cool extremities. A key challenge is that infants cannot communicate their discomfort, so vigilance is critical.

Elderly Adults:

Aging reduces the body’s ability to regulate temperature. Peripheral circulation slows, and underlying conditions like diabetes or hypothyroidism increase vulnerability.

Medications such as beta-blockers or sedatives can mask hypothermia symptoms, delaying diagnosis.

Healthy Adults:

Even young, fit individuals are not immune. Factors like wet clothing, prolonged exposure to wind, and exhaustion can rapidly lead to hypothermia, particularly in high-stakes environments like hiking, tactical operations, or cold-water immersion.

Key Diagnostic and Evaluation Points

1. Core Temperature: Always prioritize obtaining a core temperature using a rectal, esophageal, or bladder thermometer for accuracy. Skin thermometers are unreliable.

2. Neurological Signs: Confusion, slurred speech, and unsteady gait are early indicators of hypothermia’s impact on the central nervous system.

3. Skin Assessment: Cool, pale, and clammy skin indicates peripheral vasoconstriction, while paradoxical undressing points to advanced stages.

Why Hypothermia Requires Vigilance

Hypothermia isn’t just a condition; it’s a cascade of physiological failures. Left unchecked, it impacts every system in the body, from cardiac arrhythmias to metabolic derangements. Recognizing the subtle signs early and implementing controlled, deliberate treatment are the keys to survival.

Wrapping Up

By understanding the stages, physiological effects, and unique presentations in different populations, we can better anticipate and manage this silent killer. As part of this week’s Scenario Saturday, we encourage you to reflect on what you’ve learned and consider how these lessons apply to real-world situations. Whether in the field, at home, or in the classroom, preparation and vigilance remain the best defenses against hypothermia. Whether you’re a first responder, parent, or outdoor enthusiast, vigilance and preparation can make all the difference.