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Hi, I'm Jack. Uh, make sure you wrap up nice and warm as we're gonna be taking a dive into everything cold. So we're gonna have a hypothermia, freezing injuries, um, such as frostbite and nonfreezing injuries. Um, I'm a GP and based in Cheltenham. Um, this is a, a picture actually of Antarctica that I took when I was working as a ship doctor down there, um, a few months ago. And, um, certainly, yes, Antarctica's very cold and, um, with the expedition world a lot, a lot of the, um, exciting stuff that we go to tends to be in high mountains or extreme polar environments where it's really important to know about treatment of cold injuries. At the same time people die from the cold every year in, in countries as mild as, as the UK. And it's, um, it's really good to know um, no matter what field you're in, in the exposition environment that you, you know how to treat it. So, um, without further ado I start talking about hypothermia, accidental hypothermia is defined as the drop in core body temperature, um, unintentionally to, er, 35 degrees or below. Uh, it's worth looking at the Wilderness Medicine Society consensus guidelines, er, on this as they updated it a few years ago and there can be a little bit of a debate about, um, the different models, um, and staging of hypothermia. This is partly because everyone reacts differently to the cold and it doesn't tend to be a completely clear toto or threshold, um, from where, um, the different levels of hypothermia kick in. But as a general rule, the stage, the Swiss staging system um is quite good to go off. Um where stage one people are conscious but they're shivering. Um So that's temperatures less than 35. Um The temperatures then below 32 they start to kind of lose their consciousness. Um Now, shivering is an interesting one. Cos you always think, oh, they aren't shivering. It might not be too bad, it might not be too cold, but actually, it's a very bad prognostic sign if, if people have stopped shivering, um it should suggest their body's um not correctly adapting as it should be to the cold and they're starting to deteriorate into more of a profound hypothermia. So stage two is um also also known as moderate hypothermia. Um And then we go into stage three when you drop less than 28 degrees um in the Wilderness Medicine Society guidelines. They, they describe this as severe hyperthermia and people are often unconscious. Um Maybe they might well come across as dead. The pupils might be fixed and dilated, you might not be able to feel a pulse on them. Um They'll be feeling as, as cold as marble. Um And then stage four is um definite apparent death. Often they might almost be like Riggle mortis uh in their frozen states. Their um poor temperature. Um it will be less than 24 and it's classed as profound hypothermia in the W MS guidelines. S of hypothermia. Um mild hypothermia is something that some of you may have experienced before um in the very early stages. So there's something called the les. So it's where you get, um you might start to rumble more. You might notice people aren't really able to enunciate so well and start mumbling, they'll be fumbling around, struggling to get their Caribbean Eli in struggling to get their jacket zipped up. Um You might find that the starters stop picking their legs up in front of you and stumbling. Um The risk of that is that they go on and develop a tumble. Um Often people don't actually have the insight into this is hypothermia. You need to stop and get warm and may then also be quite um adamant that they're fine and that it further increases the risk of things progressing um to death. So, shivering is um is a, a factor that often comes in here which can be very um very profound shivering. Um The heart rate and respiratory rate will often be increased in moderate hypothermia. This is where people may start getting muscular rigidity. Um There's no more signs of shivering, which as discussed as a bad prognostic sign. Um Now the changes on the myocardium, uh probably one of the biggest risks at this stage where they're very prone to um bradycardias and tachyarrhythmias. Um ventricular fibrillation where your ventricles, the large chains of your heart are just vibrating rather than pumping properly, means that you're not pumping blood around your body and perfusing your brain. Um And that um subsequently leads to cardiac arrest. So we always say if you're gonna be rescuing someone with hypothermia that you um have to handle them very gently as the slightest hit on the chest or something might be enough to um trigger a irreversible tachyarrhythmia. Now, severe hypothermia. Um It is when you think someone really is dead, they've got no signs of life. So their pupils are fixed and dilated. Um They won't have a pulse, they won't notice any breathing. Um They obviously won't be moving at all. Uh They're completely unconscious. Um But we always say that you're not dead until you are warm and dead. And I really interesting case of this is that of Anna Bam, uh which some of you may have heard of before. Um In short, in 1999 she was a doctor who was skiing after work in Norway. Um as is the quality of life out there and she unfortunately went underneath um an ice sheet over a, a stream and she got trapped under this ice sheet submerged in the water. Luckily managed to find an air pocket for herself. She was um there was no signs of life after about 40 minutes. Um her two colleagues, she was with wave to kind of keep hold of her skis to stop her slipping further underneath and they arranged a seeking helicopter to come um along with a rescue team. Um it was about 80 minutes before they managed to finally break through the ice and get her out. And by the time she got into hospital, her full body temperature, if anyone can guess was as low as 13.7 degrees. So this is an accurate reading um done in the hospital. Um They went ahead and went straight into doing some echo. Um They noted that there was no signs of life at the time, but then she actually made a remarkable recovery. Um Initially, things were quite tough. She um came round after about a month and she was paralyzed from the neck down. She was in the hospital for a couple more months. So she gradually started to regain um movement and ability. And um I'm pleased to say that she's now back to paying, paying her taxes and is working as a radiologist in the hospital that saved her, um not showing any neurological compromise at all. Um So it's really quite incredible and, and it's really been er, quite useful uh to indicate how critical it is to give people who are profoundly hypothermic, that little chance of life. And a lot of this came down to the very good CPR she got from the two doctors with her. Also the fact that they were used to dealing with um profoundly hyperthermic patients in this part of the world. Um and the kind of the quick rescue available. But, you know, there's no reason why in a lot of our scenarios in the world, in a setting, this isn't something that um if needed, that we could try and um recreate and remember not to declare anyone dead until the war were dead. Would you mind the risk factors for hypothermia? Um You've got those non modifiable risk factors. So when you get older, um if you've been injured, um if you've not been able to move at all, um if you're stuck down due to bad weather, for example, um obviously, things like malnutrition, that's what really impacted on. Um Scott's last expedition. It's a kind of combination of the cold and the, the malnourishment that likely impacted their demise. Sadly, um modifiable risk factors is, is stuff that hopefully being people quite key in the outdoors, we're quite good at getting the right kit, which is quite critical, making sure you have the right equipment and clothing, um making sure that you've got decent um hydration that you're not um getting very dehydrated and um, obviously things like fitness does have a, a good impact. Um, now, with any kind of heat loss, um, there are the four main ways radiation, convection, conduction and evaporation. And generally if you have a cold casualty, those are the four things that you're trying to protect against. So the treatment of hypothermia, it's likely that others in the group are at risk. So it's really important that unless someone's fallen to a frozen lake or there's a very obvious reason why they've become a lot colder. That one of the first things you should be doing is helping to protect everyone else from the group. So whether that's setting up a shelter, getting a stove on and whether that's kind of getting out of the conditions or evacuating, it's really important to, um, to consider that you must also prevent any further heat loss. So there's four ways of losing heat, you want to be sure without losing anything else. So group shelters are very good. They help them to get you out of the wind and sharing body heat to help to um, create that little microclimate inside them where things can get a lot warmer. Um, getting people off the ground is really key. So getting them to sit in their backpack if they're injured or getting them on a on a nice kind of therm arrest, um, make sure you give them some nice warm fluids and some fuel if possible, which actually shows that it helps to increase um body metabolism, body heat. Um If we're gonna be rearming in the wilderness environment, we tend to do it quite, quite slowly. So, um nt 0.5 to one degree an hour using sort of clothing and heat packs. And as we said, I, if they're unconscious, you've got to treat people very, very carefully, move them very slowly. Uh Something as much as putting in a, a little airway adjunct in can be enough to cause an arrest. And with CPR wise, certainly, uh it can help to save a life. But if it's something that you're gonna start and have to stop again, um, it's important that you, er, that you only start it if you know, it's something that you're gonna be able to continue doing, um, visit CPR is sometimes an option. So that's where you'll, if you haven't got very many rescuers, you might do five minutes of CPR, then five minute off, five minutes of CPR, five minutes off, you'd only do this in something like a code casualty where um, the thoughts are that the cells in the brain have pulled down so much that, um, in Anne Bagan home's case, it was thought she was using about 10% of um, her normal um metabolism in the cells and therefore she, her brain cells didn't get starved of oxygen and that's where intermittent CPR can be effective. And evacuation plans are obviously key ok, onto frostbite. And nonfreezing cold injuries. So freezing cold injuries tend to be um divided into frostbite and frost knit. Um frost knit tends to be a lot less severe, um tends to be reversible and doesn't cause long term damage. Um whereas frostbite can be significantly more severe and result in loss of limbs, um digits. So frostnip quite often can precede frostbite. So it should normally be seen as a significant warning. Um It's a very superficial um freezing injury. Um If it's uh it normally kind of comes across as it kind of looks like almost like wax from a candle has been dripped onto the um onto the cheeks or the nose or the fingertips. It tends to be um areas of skin exposed to the prevailing cold and wind. Um It resolves quickly um within about 30 minutes of rewarming and doesn't cause any long term damage. A frostbite. It itself is um a tissue injury that results in exposure temperatures below the freezing point. Um for a sustained period of time in the skin. Um, severity is proportional to the temperature duration of exposure and amount and depth of frozen tissue. Um So all all quite logically makes sense there. It's worth looking at um for Ray, he's a um quite well known expedition doctor in the UK. Um He's done the seven summits and uh has set up a, a frostbite service um in the UK. He's a vascular surgeon. So it nicely um overlaps between exposition medicine and, um, and his day job, but he can be very helpful, um, particularly if you're ever find yourself working in a remote rural hospital. And, uh, you can always contact to us about advice on severe frostbite as a general rule though. It's try and hold off, um, any surgery at hospitals for as long as absolutely possible as it's amazing how much can actually recover. So, we'll just go through a few photos here to give you that idea. This is um day two of significant um frostbite from kite skiing across Greenland with shoes that were too tight in very cold conditions. As you see, it's um significantly improving. It's starting to look very black. And um if you look at day 10 and compared to day 39 they're now starting to demarcate quite clearly, quite nicely. You can tell what part of the foot is, is dead tissue and what's improved. Um And then that's when they've go ahead with some amputations um still waiting for some demarcation and that's the feat now, so almost a year later, um considering what the injury looked like initially, he's not actually lost that much in the way of his toes. Now, from the exposition setting and what's more relevant to us is um how to manage it. So Ibuprofen is really good. It helps to reduce the prostaglandin and Thromboxane production um which can lead to vasoconstriction and further vasoconstriction reduces the blood flow to the tips of the toes which can then cause um further issues with frostbite um due to a lack of blood and heat coming to the toes. But the key thing with um most things in the exhibition setting is prevention is so key. So make sure that the patient themselves has a decent core temperature. Cos if your core temperature is dropping, you're much more likely to suffer from frostbite. So everything we said about hypothermia, uh we managed to prevent against that that should help in some ways towards your preventing frostbite. Make sure all skin is covered. It's very useful to have a buddy system so that two of you can check up, make sure that nothing's been missed. Um Make sure that things are fitting well. So if your boots are too tight, your gloves are too tight. Um It, it's gonna start causing issues with restricting blood flow which predisposes the digits to frostbite, adequate nutrition. Um So Scott of the Antarctic and Shackleton, um both from the exhibitions, there were issues with frostbite and a lot of that was likely to do with after months of expedition and had a real lack of um fresh fruits which was obviously suspected for some, some scurvy in the group. Um but also uh likely um contributed to their sort of poor nutrition and making them more, more predisposed to frostbite. Uh Berry, berry was also um likely to have affected them then which was generally seen in um in Asia with people who just eat um white rice. But actually, in hindsight, was probably affecting our um explorers of the um heroic age of exploration. Um a lot more than we realized at the time. Ok. Um Make sure you protect frozen tissue from damage. Um You're not thought if there's risk of refreezing. So if you've got a frozen lim and uh you don't have any good signs of evacuation for another week and it's very likely it's gonna be getting very cold every night. Um, it's best to keep that limb cold. Um, often it's not painful when it's cold where it's profoundly painful when it starts re warming and, um, and best not to kind of keep using extremities that there are frostbit and that can make things worse. Um And yeah, as, as we said, it's the, it's the high dose, the 800 mg of, of Ibuprofen, um, which, which can help to, to get on top of, of frostbite. I think it's worth just adding a couple of things in before we talk about the nursing care of frostbite. Um, because as part of your um kind of pre expedition planning and preassessment of people, um, if you get into very cold areas, you would be thinking about, um, whether you want to be taking clients who uh have bad diabetes, um have bad peripheral vascular disease or they smoke, they drink a lot of alcohol. Um, if they uh have anything like Raynaud's disease which affects the circulation of the fingers. Um, and also they're on certain medicines. So, things like beta blockers, um, people off and on for the heart or for anxiety and certainly reduce your circulation to your, um, your disk or digits, um, cause vasoconstriction there and predispose you to frostbite. Um, same with, um, medicines like sedatives, neuroleptics. Um, and certainly smokers, they'd all be at higher risk and, and it would be certainly be worth keeping a closer eye on them or, or discussing whether they should be coming on the expedition in the first place, um, onto nursing care. So it's really important that once they are somewhere that's warm and it, it's suitable and appropriate for them to, to start thawing that it's done, um, sort of quite carefully. So you want to have water not going above 40 degrees, um, where you can put the hand or foot in a bucket, make sure it's continuously being stirred to ensure good heat exchange, um, and give them some anti-inflammatories to help with the, the pain. Um, blisters. Generally, they say it's best not to burst them uh as that can then, but I make it likely more likely to get infection, any signs of infection, something like flucloxacillin is a good antibiotic to treat them with, um, at frozen feet. It's really good to try and keep the legs elevated, not to allow weight bearing or walking on them. And um, Aloe Vera has been shown to have some, some good evidence. So it's, um, it's a nice kind of herbal treatment which can help with reducing the, um, the vasoconstriction through reducing the prostaglandins and thromboxane. So overall take home me, me, take home messages, um, with cold injuries. Um, prevention is certainly much better than cure, um, to make sure that you've got the right kit, um, in the right place, um, that you've got things like body checks there that if you've got gloves, you've, you take them to your, to your hands or your jacket or you use, um, child loops or what I like to call idiot loops. Um, because, you know, if you're taking your glove off to get a nice photo, um, you're not gonna lose your glove, which in, in some high altitude, cold environments, you know, could certainly, um, almost guaranteed frostbite into that hand. Um, make sure that we are rewarming patients. Um, who've got moderate hypothermia or below that, it's done carefully and slowly, um, don't start a CPR unless it can be continued and don't rearm frozen tissue if there's a risk of, of it refreezing. Um And also as we saw in those photos, feel free to go through them again, but frostbite does actually often recover surprisingly well where you think they might have to lose a whole foot and it ends up being a couple of toes. So it's always worth seeking expert advice on that. Um And there's telemedicine availability which you can send kind of photos or communication through to satellite phones if you are somewhere remote and need advice on that. So, um yeah, I hope that was helpful and uh we're very happy to help with any questions when we see you at the face to face. Course. Thank you.