Hypothermia Prevention Webinar | Featuring Jamie Pattison

Last week, THERMARMOUR were thrilled to host our inaugural Experts in Industry webinar, ‘Forget temperature: ALL casualties are at risk of hypothermia’, featuring SAR Winch Paramedic, Jamie Pattison. The session focused on practical strategies for hypothermia prevention and treatment for first responders working in all environments, from mountain rescue to community first response.

We were introduced to Jamie through the World Extreme Medicine Fund, and over the past 12 months, he’s been putting our products through their paces in some of the harshest environments across the globe. When he’s not being lowered from helicopters as a winch paramedic, Jamie volunteers with mountain rescue, provides expedition medicine on glaciers, and supports UKISAR — most recently deploying to Mozambique to assist with the flooding response.

The webinar covered a wide range of topics, from understanding the mechanisms of heat loss to patient warming strategies and what to include in a hypothermia prevention kit.

In this blog, we’ll cover the key takeaways from our hypothermia prevention webinar, featuring insights and real-world experience from Jamie.

Understanding Hypothermia and The Risks

Treating or preventing hypothermia starts with understanding why it happens.

Prevention is far better than a cure, and our bodies are constantly gaining and losing heat through 5 mechanisms:

Evaporation (moisture on your skin turning into a gas and removing body heat.)
Convection (water or air moving over your skin, picking up heat energy and taking it away from you.)
Radiation (our bodies radiate heat, and the universe’s natural state is a cold, dark place, and it wants to return to that. It’s constantly trying to bring that differential together by taking body heat away.)
Conduction (losing heat energy due to contact with a cold surface and conducting heat energy away from you)
Metabolism (human metabolism relies on an optimal body temperature range, approximately 37°C, to function efficiently.)

Early recognition and accurate assessment is very important to prevent hypothermia from progressing and factors such as alcohol use, lack of proper equipment, injuries, age, and patient vulnerability can increase risk.

Cold Environments and Physiological Responses

The body has lots of physiological adaptations when experiencing cold environments. In these conditions, the human body triggers an acute response, with receptors and sensors in the skin and brain detecting the cold and signalling that heat is being lost, prompting the body to take action to prevent further heat loss.

The human body adapts to this cold through vasoconstriction, a process where blood vessels near the skin tighten to limit blood flow. This helps reduce the temperature difference between the skin and the environment. We also have an increase in heat production, which starts the shivering sense.

Key tips in cold environments:

Observing behaviour and body language to assess risk is essential, noting that fully layered individuals may be at higher risk than those still able to add clothing.
Always over-triage casualties that are ill, injured, or unable to help themselves.
Consider age and underlying medical conditions as factors, rather than relying solely on demographics.

Risk Factors Associated With Hypothermia

Extremes of age (young children are particularly at risk because they have a high surface area compared to their body mass and an underdeveloped hypothalamus—the part of the brain responsible for regulating body temperature. The elderly are also at risk due to deficiencies in their hypothalamus, skin differentiation and medication.)
Alcohol (Intoxicated patients lose heat because alcohol affects the body’s natural temperature regulation.)
Medication/medical issues
Lack of equipment (lack of equipment to keep people warm can be quite stark at times, this can be life-threatening)
Illness/injury (if your normal physiology is out of whack, you’re losing blood or you’re shocked, you’re much more susceptible to hypothermia.

If a patient is ill or injured at any point throughout the patient journey, and hypothermia is involved, they are likely to experience longer hospital stays and an increased risk of infections.

Revised Swiss System

Hypothermia starts when body temperature drops below 35°C, and it’s classified into 3 stages:

Mild – 35°C-32°C (shivering, sensation to cold, numbness of hands, unable to perform with hands, irritable, able to walk and talk)
Moderate – 32°C-28°C (intense shivering, worsening ‘umbles’, stumbling, sluggish movements, confused, slurring, ‘don’t care’ attitude)
Severe <28°C (shivering stops, irrational behaviour, slower heart rate, loss of awareness of others, appear dead, reduced GCS)

Pre-hospital temperature measurement with a thermometer is very unreliable. First responders frequently recover patients from cold water; their ear canals may be filled with cold water, and the thermometer probe itself can be cold, making readings unreliable.

Clinical signs are often more reliable than temperature readings alone, especially in field conditions.

For unconscious patients, an oesophageal probe can be inserted down the oesophagus and positioned near the heart to provide a more accurate measurement of core body temperature.

The evidence-based Revised Swiss System, which simplifies things for us:

Look out for the “Umbles”:

Mumbles – quiet, slowed or slurred speech
Grumbles – change in behaviour, negative attitude and complaints
Fumbles – reduced fine motor skills, difficulty operating buttons/zips due to cold peripheries
Stumbles – off balance, falling behind, tripping over
Tumbles – disorientation, reduced conscious level and potentially some nasty injuries

Effective Hypothermia Management

The webinar explored practical strategies for preventing and managing hypothermia:

Patient warming: Using a multi-layered approach including vapour barriers, insulative layers, and waterproof/windproof outer layers.
Environmental control: Minimising heat loss with shelter, managing the mechanisms and careful patient handling.
The “burrito” method: Wrapping patients in layers to retain body heat.
Hypothermia prevention kit: Bothy bags, vapour barrier, insulation, wet for dry clothes, and emergency blankets.
Control the environment: Manage convection, conduction, evaporation and radiation. Bothy bags create small microclimates/group shelters that protect casualties from the elements and help warm them up.
Wet for dry clothes: If dry clothes are available, swap them for wet ones. If not, make sure the vapour barrier is applied thoroughly, as this will trap the water and prevent heat loss through evaporation. As well as this, make sure you control the environment – get the casualty into some shelter.
Treat like porcelain: Cold hearts are more prone to arrhythmias, and handling patients too vigorously can trigger these irregular heartbeats, or even lead to cardiac arrest.

The Burrito Wrap 🌯

Inner vapour barrier: foil, plastic wrap or emergency blanket placed directly against dry clothing or skin. Add heat pads to the patient’s chest if needed. This is really important for preventing evaporation, especially if the patient is wet.
Insulation: add an insulation layer, ideally made out of man-made fibres or wool, which will stay warm even if it’s wet, such as a sleeping bag or blankets.
Ground insulation: Sleeping pad, foam mat, rucksack to insulate from the ground
Waterproof barrier: a water/windproof layer, to prevent any water or wind ingress.

*Face remains exposed for airway management and monitoring