Lucky and Incredibly Fragile: Treating Hypothermia on the Water

This is episode three in a three part series discussing cold water immersion. In episode one I talk about understanding what cold water immersion is and is not. In episode two we discuss surviving cold water immersion. In our final episode, I talk about how to treat someone who has been exposed to the cold so that they survive the experience.

Hypothermia is a true emergency. Someone who has been pulled from cold water is two things. They are lucky to be alive and incredibly fragile. We’re not just talking about the person who has been rescued from the drink. We’re also talking about the guy who’s been on watch at night and you come up on deck to take over and find him shivering and confused. Hypothermia snuck up on him slowly. What can we do to treat the hypothermic patient onboard?

Two Stages of Hypothermia

In the hospital setting, there are four stages of hypothermia; mild, moderate, severe and profound, each with a different temperature range. Practically speaking, it’s unlikely we’re going to take a temperature in the middle of a crisis at sea. I love how Jeffrey Isaac PA-C (my offshore medical idol) and Dr. David Johnson have narrowed it down to two stages in their book Wilderness and Rescue Medicine, 6th edition. They make the distinction realistic: can the patient cooperate with our treatment or not? A very cold patient who is not awake or not shivering and can’t cooperate with treatment is severely hypothermic.

A mildly hypothermic patient is awake, but subdued and may be confused, withdrawn or lethargic. We call these mental status changes and in the ER tell people to look for someone not acting like themselves. They will be shivering, have cool, pale skin and perhaps a loss of coordination.

The process starts with getting the person out of the water. In Episode One, we talked about the circum-rescue collapse. That time immediately before, during or after rescue when anything from fainting to death can happen. It’s when the stress hormones can leave us with the mental relief of getting rescued causing a sudden drop in blood pressure. If we’ve headed into hypothermia and our core temperature has dropped, the heart itself is super fragile and any amount of jostling can cause it to stop pumping (ventricular fibrillation is the cool medical term for this). If we’re jiggled about during this time, it can also send the cold blood from our arms and legs rushing back to the cold, delicate heart, stressing it further. In addition, what we’ve learned through that fateful Fastnet race years ago and other similar scenarios, the hydrostatic pressure of the water itself helps keep our blood pressure stable. The act of being pulled from the water can violate all of the above. We can trigger fibrillation with rough handling and upright positioning. The way to minimize the risk is to get the victim out of the water as horizontally and gently as possible. Don’t make the person work for it if you can help it. That’s the perfect world version. Getting them out of the water is priority one. Do what you have to do and forgive yourself if it’s not perfectly textbook. Get them horizontal as soon as you can.

Lucky and Incredibly Fragile: Treating Hypothermia on The Water

Ideally, pull anyone out of cold water as horizontally as possible. Don’t make them work for it if you can help it. Image courtesy CWBC.

Once out of the water, get the patient off the cold, wet deck and down below out of the wind (horizontally please), to prevent more heat loss from conduction and convection. Cut off their clothes with the bandage scissors from your well stocked first aid kit. They cut cloth, not friends. This is part of the gentle treatment. We don’t want to put our cold, wet friend through a tug of war getting their soaked clothes off. Blot them dry gingerly to prevent heat loss by evaporation. No forceful rubbing please. Then wrap the patient up in loose layers to trap their body heat. DO NOT strip off your clothes and get into the sleeping bag with them. This is not the time for that. It’s too much joggling.

Treating Mild Hypothermia

The very best treatment on the water for mild hypothermia is vigorous shivering and it only requires two things: fluids and fuel. The body’s attempts to rewarm itself will burn a ton of energy and use plenty of fluids. We need to keep them hydrated and we need to get them calories in a hurry. Simple sugars are best at first. While warm cocoa or tea with honey are a nice touch, they’re time consuming to make and not strictly necessary. Calories are more important than the temperature of the liquids. A cold Coke is a better choice then black coffee. At some point, when you do give them warm, sugary liquids, use caution as sensation may be decreased and they could easily burn their mouths on hot liquids. The confused guy who got hypothermic insidiously over time on watch, he is not to be trusted. It’s not enough to tell him to go below and get warm. We need to treat him like a toddler. Follow him below and make sure he gets warm.

Keep the patient lying flat to maintain their blood pressure, prevent their circulatory system from collapsing and protect them from further injury. Ignore any complaining about this. Remember the Norwegian fishermen from Episode One? We can have a huge impact on rewarming aboard, but it takes a long time, some estimate over 40 minutes, of shivering, sugar, fluids and rewarming for it to be safe for the patient to get up and move around. All hypothermic patients’ body temperatures will drop first, before their temperatures go up. Letting the patient up too soon will make this worse. In some cases, these treatments may be all that are needed. That said, be very sure they are completely alert and improved before considering letting them begin to move. If they are not improving, it’s time to implement your evacuation plan.

Severe Hypothermia

In more severe hypothermia, when the patient isn’t awake, isn’t shivering and/or can’t participate in the fluid/fuel plan, the best treatment is rewarming at a hospital. After we initiate our evacuation plan, and while we wait for rescuers, we can place warm packs around their abdomen, groin and armpits. On a boat, we can do this with chemical warm packs (the packaged kind we shake up and put in our boots at Green Bay Packer games), warm water in bottles or hot rice packs. Use caution so as not to cause skin burns. We need to treat these patients EVEN MORE gently to prevent ventricular fibrillation (cardiac arrest). We can give them warm, humidified oxygen. Do you have any on your boat? Wait for it… Yes! It’s your own warm breath. Breathe above their mouth. If they aren’t breathing or not breathing well, use rescue breathing (positive pressure ventilation) like we learned in CPR class to get warm humidified oxygen directly into the lungs. If you have the supplies and training to start an IV with warm fluids, preferably with some dextrose, do it! Never do anything to aggressively rewarm victims. DO NOT plunge them into hot water or put them in a hot engine room.

Lucky and Incredibly Fragile: Treating Hypothermia on The Water

Remember: “You’re not dead until you’re warm and dead!” Image courtesy Dave Dyet, free

Severe hypothermia can look like death. Patients with severe hypothermia, however, have been successfully resuscitated with good neurologic outcomes. Cold is protective to some degree. There’s an old adage in emergency circles that says, “You’re not dead until you’re warm and dead”. In other words patients should be rewarmed before being pronounced dead. CPR on the severely hypothermic is a bit controversial, but most agree that an attempt is worthwhile if your patient has no detectable pulse. Do so only as long as you can without exhausting yourself. Use your best judgement, do what you can with what you have while you wait for rescuers to arrive.

Here are some resources for further study if you’re interested:

  • – Gordon Geisbrecht aka Dr. Popsicle.
  • – Gordon Geisbrecht.
  • – If you’re an experiential learner and want to get dunked in the drink, this training by Mario Vittone, retired USCG helicopter rescue diver, safety at sea expert, maritime risk consultant and all around good egg might be for you.
  • – Baby It’s Cold Outside is a series of free online modules on rescue and hypothermia by Dr. Popsicle.
  • Here is a printable card put out by BICO (Dr Pop) that’s given away at Safety at Sea Seminars.


This wraps up the three part cold water series. Did you love it? Please leave any comments or questions you have below. Have you ever had to treat someone with hypothermia? I’d really like to hear how you handled it. Thanks again for reading. I look forward to sharing more useful info with you soon as we learn how to keep each other safe on the water. Stay tuned…

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