Hypothermia - very good article
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Yeah but Ronnie that's the whole point.
That is wildly wrong and yet its being touted as fact.
There's people who teach what they have garnered from text books and research, and those who have done the time and learnt the skills and then passed it on. This article was written by the former, and to be honest - I don't have time for it.
And I fully agree with your point. There have been posts on here frequently where similar situations apply. The problem is that, despite the fact that there is a "warning" post at the start of the likes of the medical thread, people will take these things as "gospel"
I know I shouldn't care.......but it bothers me!
I think we agree and are arguing over the minutiae. Such is the nature of what we do I suppose.
I think we agree and are arguing over the minutiae. Such is the nature of what we do I suppose.
We do, and the same as we have done previously.
Between me and Craig? It's the nature of what we do. We are in broad agreement and debating the details. It's healthy.
Arguing over the article? Well that is different. People pick up on things they read and comments like....
...are of concern because it's so very wrong. It could result in someone trying to frantically warm up an unconscious person because they have a temp of 36 degrees in the belief they are hypothermic, while missing or not looking for the reason they are unconscious. A far fetched example, but this is the reason that healthcare professionals are either incredibly vague or very precise in their comments. It needs to be right.
Hi
Thanks to Martyn and Bothwell_Craig for an interesting debate.
Sorry for my slow response to this debate - I've just returned from a camping trip in arctic Sweden.
Pierre picked up on this but in my article I'm not trying to contradict the accepted medical definition of hypothermia. What I'm saying is that in the outdoors, since you can't practically take core body temperature readings, you need to look to signs and symptoms of people being cold other than core body temperature. In the outdoors, people will typically show signs of being cold before their body core temp drops to 35 degrees. Why wait to do something about it until they get this cold?
In the following video the subject's core body temperature gets down to 35 degrees but he is clearly showing signs of being cold long before this. If an outdoor leader ignored the signs and symptoms discussed in this film - which are present in this case between 37 and 35 degrees - you could argue they were negligent. From this perspective, the medical definition of hypothermia being below 35 degrees is irrelevant in an outdoor setting. You need to sort out the problem before they get so cold. Hence my suggestion to be more pragmatic about the definition in a remote wilderness setting, not in an intensive care ward or other medical facility.
The relevant part of the video is 5 mins long and starts 2 minutes 20 seconds in. I'd be interested to hear Martyn and Bothwell_Craig's opinions on it..
[video=youtube;c_Vxxbh6Czg]http://www.youtube.com/watch?v=c_Vxxbh6Czg[/video]
All the best
Paul
Thanks to Martyn and Bothwell_Craig for an interesting debate.
Sorry for my slow response to this debate - I've just returned from a camping trip in arctic Sweden.
Pierre picked up on this but in my article I'm not trying to contradict the accepted medical definition of hypothermia. What I'm saying is that in the outdoors, since you can't practically take core body temperature readings, you need to look to signs and symptoms of people being cold other than core body temperature. In the outdoors, people will typically show signs of being cold before their body core temp drops to 35 degrees. Why wait to do something about it until they get this cold?
In the following video the subject's core body temperature gets down to 35 degrees but he is clearly showing signs of being cold long before this. If an outdoor leader ignored the signs and symptoms discussed in this film - which are present in this case between 37 and 35 degrees - you could argue they were negligent. From this perspective, the medical definition of hypothermia being below 35 degrees is irrelevant in an outdoor setting. You need to sort out the problem before they get so cold. Hence my suggestion to be more pragmatic about the definition in a remote wilderness setting, not in an intensive care ward or other medical facility.
The relevant part of the video is 5 mins long and starts 2 minutes 20 seconds in. I'd be interested to hear Martyn and Bothwell_Craig's opinions on it..
[video=youtube;c_Vxxbh6Czg]http://www.youtube.com/watch?v=c_Vxxbh6Czg[/video]
All the best
Paul
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The problem is Paul, you are hard-linking these signs and symptoms to a specific temperature range and that is wrong. Absolutely, you should observe the signs and symptoms - in fact they are far, far more important than a specific temperature. People can have a temp of 35.5 degrees on a balmy summer day, with no problems whatsoever but under your definition, they would be hypothermic. The most common temperature range is 35.5 to 36.5 - if you dont believe me, take yours now and tell me what it is? I can almost guarantee that almost everybody will have a temp below 37 degrees. But under your definition, all these people would be hypothermic and they are obviously not. It doesnt matter if you are at home in central heating, or out ion the woods, your temp will almost always be below 37 degrees. That is perfectly normal and does not ever make you hypothermic. It's simply wrong to identify anything below 37 degrees as hypothermia. The reason the medical definition is 35 degrees is because anything below 35 is an abnormal temperature and at that point, your body's thermal protection mechanisms are failing to maintain it's core temperature. It's also possible to be extremely cold and at very high risk with a core temperature of 36 degrees. You simpluy cant look at the temperature as the definitive (unless it's below 35 degrees). Learn and focus on the signs and symptoms of hypothermia and forget all about temperature - or stick to the accepted medical definition.
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Martyn
Thanks for your reply. I agree that hard linking to temperature is wrong and that we must learn to recognise signs and symptoms. This is why I wrote the following in my article (my bolding for the purpose of this reply):
"The pitfall with a categorisation based on body core temperature is that its not possible to monitor internal body temperatures in the field (even if you are very good friends, using a rectal thermometer while on the slopes of Ben MacDui is not practical). A drop in core temperature will affect every part of your bodys system so we must look for the signs and symptoms of these changes".
Which is why I then go on to relate signs and symptoms in terms of woolier 'mild', 'moderate', 'severe' and 'deep' hypothermia. But even to that I added the following caveat (again my bolding here for the purposes of replying):
"It should be noted that fitting signs and symptoms into corresponding classifications of mild and moderate hypothermia are largely based on experiments involving the immersion of subjects into cold water, while the categorisation of the signs of severe and deep hypothermia come from individual case histories, all of which have shown some variation, not least in mortality rate.
What you might observe in your companions on a wet and windy day in October on the slopes of Snowdon or Mount Washington, could be different to the above. Experiments suggest maximal shivering occurs at a body core temperature of 35oC (95.0oF) but rescuers have reported no shivering in some hypothermia casualties at this temperature. Shivering normally ceases below 31oC (88oF) but has been recorded below 29oC (84oF). Unconsciousness normally comes between 33oC (91oF) and 27oC (80oF) but some patients have been verbally responsive at 26oC (79oF), a temperature at which others have died."
As for sticking to the "accepted medical definition", the medical profession can also be pragmatic; for example in Ch16 'Treatment of Accidental Hypothermia' of 'Medical Aspects of Harsh Environments, Volume 1. Textbooks of Military Medicine. Washington, DC: Borden Institute, Office of the Surgeon General, US Army Medical Department' (which is written by medical doctors) it states (my bolding):
"To allow for the diurnal variation of one to two Centigrade degrees, a person is considered to be in a state of hypothermia if the core temperature is below 35oC. Obviously, medical officers should not view this threshold with the attitude that hypothermia does not exist when the core temperature is 35.5oC and therefore the patient is safe, whereas a core temperature of 34.5oC is diagnostic of hypothermia and the patient is in danger."
One of the authors of Ch16 was Evan L Lloyd, an Edinburgh-based consultant who wrote the book 'Hypothermia and Cold Stress' in the 1980s. While this book may be out of date in some respects, it is worth reading the introduction for its historical perspective.
In the introduction, the author also writes of non-medical profressionals making remarks or observations about hypothermia "If clinical observations are made, the nonentity of the observer, at least in medical eyes, or the lack of scientific 'measurement' may mean that the information is dismissed as anecdotal or hearsay". Is history repeating itself on this forum?
A free copy of Evan L Lloyd's book can be had here:
http://books.google.co.uk/books?id=2Zc9AAAAIAAJ
The medical profession can also be inconsistent with the "accepted medical definition". For example, in Ch 17 'Cold Water Immersion' of the same medical textbook 'Medical Aspects of Harsh Environments, Volume 1. Textbooks of Military Medicine it states:
"The data are divided into three ranges of core temperature: mild hypothermia, 37oC to 33oC; moderate hypothermia, 32oC to 27oC; and severe hypothermia, 26oC to 18oC".
This chapter was authored by Lorentz E. Wittmers, MD, PhD, Associate Professor, Department of Medical and Molecular Physiology, and Director of Water Safety Laboratory, University of Minnesota School of Medicine.
But at the end of the day, let's not get bogged down in semantics and definitions. Where we are in total agreement is about what is most important - being able to spot the signs and symptoms. And spot them early! I think even Ronnie would agree with this?
And Ronnie - the whole point of people doing research and writing it down is that other people can read it and learn from it. For instance, while Martyn undoubtedly has his own very valuable professional experience to rely upon, the majority of the knowledge provided by his medical training is down to the work of generations of doctors and researchers before him. No disrespect to Martyn but he is 'standing on the shoulders of giants' as it were. And as developments and advances occur, this knowledge is promulgated without every doctor having to invent it for themselves. I'm not saying reading is a substitute for your own personal experience but there is nothing wrong with being able to read about and benefit from other people's work and experience too. You can have read books and have experience, you know. They are not mutually exclusive.
I'm not trying to have the last word here and I'm sure Martyn will respond. I value our ability to discuss these matters here. I think we all benefit from it.
All the best
Paul
Thanks for your reply. I agree that hard linking to temperature is wrong and that we must learn to recognise signs and symptoms. This is why I wrote the following in my article (my bolding for the purpose of this reply):
"The pitfall with a categorisation based on body core temperature is that its not possible to monitor internal body temperatures in the field (even if you are very good friends, using a rectal thermometer while on the slopes of Ben MacDui is not practical). A drop in core temperature will affect every part of your bodys system so we must look for the signs and symptoms of these changes".
Which is why I then go on to relate signs and symptoms in terms of woolier 'mild', 'moderate', 'severe' and 'deep' hypothermia. But even to that I added the following caveat (again my bolding here for the purposes of replying):
"It should be noted that fitting signs and symptoms into corresponding classifications of mild and moderate hypothermia are largely based on experiments involving the immersion of subjects into cold water, while the categorisation of the signs of severe and deep hypothermia come from individual case histories, all of which have shown some variation, not least in mortality rate.
What you might observe in your companions on a wet and windy day in October on the slopes of Snowdon or Mount Washington, could be different to the above. Experiments suggest maximal shivering occurs at a body core temperature of 35oC (95.0oF) but rescuers have reported no shivering in some hypothermia casualties at this temperature. Shivering normally ceases below 31oC (88oF) but has been recorded below 29oC (84oF). Unconsciousness normally comes between 33oC (91oF) and 27oC (80oF) but some patients have been verbally responsive at 26oC (79oF), a temperature at which others have died."
As for sticking to the "accepted medical definition", the medical profession can also be pragmatic; for example in Ch16 'Treatment of Accidental Hypothermia' of 'Medical Aspects of Harsh Environments, Volume 1. Textbooks of Military Medicine. Washington, DC: Borden Institute, Office of the Surgeon General, US Army Medical Department' (which is written by medical doctors) it states (my bolding):
"To allow for the diurnal variation of one to two Centigrade degrees, a person is considered to be in a state of hypothermia if the core temperature is below 35oC. Obviously, medical officers should not view this threshold with the attitude that hypothermia does not exist when the core temperature is 35.5oC and therefore the patient is safe, whereas a core temperature of 34.5oC is diagnostic of hypothermia and the patient is in danger."
One of the authors of Ch16 was Evan L Lloyd, an Edinburgh-based consultant who wrote the book 'Hypothermia and Cold Stress' in the 1980s. While this book may be out of date in some respects, it is worth reading the introduction for its historical perspective.
In the introduction, the author also writes of non-medical profressionals making remarks or observations about hypothermia "If clinical observations are made, the nonentity of the observer, at least in medical eyes, or the lack of scientific 'measurement' may mean that the information is dismissed as anecdotal or hearsay". Is history repeating itself on this forum?
A free copy of Evan L Lloyd's book can be had here:
http://books.google.co.uk/books?id=2Zc9AAAAIAAJ
The medical profession can also be inconsistent with the "accepted medical definition". For example, in Ch 17 'Cold Water Immersion' of the same medical textbook 'Medical Aspects of Harsh Environments, Volume 1. Textbooks of Military Medicine it states:
"The data are divided into three ranges of core temperature: mild hypothermia, 37oC to 33oC; moderate hypothermia, 32oC to 27oC; and severe hypothermia, 26oC to 18oC".
This chapter was authored by Lorentz E. Wittmers, MD, PhD, Associate Professor, Department of Medical and Molecular Physiology, and Director of Water Safety Laboratory, University of Minnesota School of Medicine.
But at the end of the day, let's not get bogged down in semantics and definitions. Where we are in total agreement is about what is most important - being able to spot the signs and symptoms. And spot them early! I think even Ronnie would agree with this?
And Ronnie - the whole point of people doing research and writing it down is that other people can read it and learn from it. For instance, while Martyn undoubtedly has his own very valuable professional experience to rely upon, the majority of the knowledge provided by his medical training is down to the work of generations of doctors and researchers before him. No disrespect to Martyn but he is 'standing on the shoulders of giants' as it were. And as developments and advances occur, this knowledge is promulgated without every doctor having to invent it for themselves. I'm not saying reading is a substitute for your own personal experience but there is nothing wrong with being able to read about and benefit from other people's work and experience too. You can have read books and have experience, you know. They are not mutually exclusive.
I'm not trying to have the last word here and I'm sure Martyn will respond. I value our ability to discuss these matters here. I think we all benefit from it.
All the best
Paul
Mate, you just cant pin diagnosis on specific temperatures in the way you are doing it in your article. I know what I'm talking about, not just from reading and professional education but from first hand experience of looking after many hypothermic patients. I've looked after patients helicoptered in off the hills with hypothermia, drunks who have passed out in the snow, cardiac arrests and numerous others, including inducing controlled hypothermia as a therapy for cardiac arrest patients using the Arctic Sun. A body temperature of just below 37 degrees is not, ever diagnostic of any kind of hypothermia and it not in any way an abnormal temperature. A body temperature of 35.5 degrees to 37 degrees is entirely consistent with a body that is perfectly able to thermoregulate itself and not one that is under thermal stress. This does not mean that this is a "safe" temperature range, but that you cannot use temperature alone as a diagnostic tool when the temperature falls within that range. That's what you've repeatedly written in your article and it is honestly, 100% wrong.
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Martyn
Thanks for your response. I've always acknowledged that you know what you are talking about. It's great to be able to discuss this matter with someone who does. It's disappointing that you've read things into my article that I didn't intend. One of the points of my article was the exact opposite of what you are accusing me of - using temperature alone as a diagnosis. Or using temperature at all. I do say in my article that taking accurate core temperatures is impractical in the field. Why then would I be trying to pin a diagnosis on a particular temperature? What I'm actually trying to say in the article is that, for most people when in the outdoors, temperature is not an option as a diagnostic tool.
Most of what I wrote in the article about signs and symptoms is qualitative, not quantitative. In my description of mild hypothermia, any temperatures cited are there for illustration, not diagnosis. There is no mention of temperatures at all in my discussion of moderate and severe hypothermia. Again deep hypothermia mentions temperatures that are data points from published research and included as illustration. From the beginning of the section 'How to Treat Hypothermia' to the end of the article there is NO MENTION OF TEMPERATURE AT ALL.
Even after my discussion of signs and symptoms I caveat with "You should also bear in mind that the signs and symptoms are, in reality, a continuum; a sliding scale". Not only am I not pinning diagnosis to any particular temperature, I'm not even pinning particular signs or symptoms into 'stages' of hypothermia because I acknowledge case histories have shown a good degree of variation.
I still stand by the assertion that in the outdoors people should be looking out for any sign or symptom in their companions EARLY, regardless of what their temperature might be (not that you would know their temperature anyway). Since you can't continuously monitor a companion's temperature in the field, it is largely irrelevant for catching a deteriorating situation early. You have to look to signs and symptoms.
What I am going to do is re-word some of the article and hopefully, this will then cause you less offence!
Martyn, I really appreciate your input on this. Thanks for taking the time to discuss it with me.
Best regards
Paul
Thanks for your response. I've always acknowledged that you know what you are talking about. It's great to be able to discuss this matter with someone who does. It's disappointing that you've read things into my article that I didn't intend. One of the points of my article was the exact opposite of what you are accusing me of - using temperature alone as a diagnosis. Or using temperature at all. I do say in my article that taking accurate core temperatures is impractical in the field. Why then would I be trying to pin a diagnosis on a particular temperature? What I'm actually trying to say in the article is that, for most people when in the outdoors, temperature is not an option as a diagnostic tool.
Most of what I wrote in the article about signs and symptoms is qualitative, not quantitative. In my description of mild hypothermia, any temperatures cited are there for illustration, not diagnosis. There is no mention of temperatures at all in my discussion of moderate and severe hypothermia. Again deep hypothermia mentions temperatures that are data points from published research and included as illustration. From the beginning of the section 'How to Treat Hypothermia' to the end of the article there is NO MENTION OF TEMPERATURE AT ALL.
Even after my discussion of signs and symptoms I caveat with "You should also bear in mind that the signs and symptoms are, in reality, a continuum; a sliding scale". Not only am I not pinning diagnosis to any particular temperature, I'm not even pinning particular signs or symptoms into 'stages' of hypothermia because I acknowledge case histories have shown a good degree of variation.
I still stand by the assertion that in the outdoors people should be looking out for any sign or symptom in their companions EARLY, regardless of what their temperature might be (not that you would know their temperature anyway). Since you can't continuously monitor a companion's temperature in the field, it is largely irrelevant for catching a deteriorating situation early. You have to look to signs and symptoms.
What I am going to do is re-word some of the article and hopefully, this will then cause you less offence!
Martyn, I really appreciate your input on this. Thanks for taking the time to discuss it with me.
Best regards
Paul
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Martyn - I fully agree with you. My personal definition of hypothermia is ≤35°C - that's based upon personal experience, not reading. I've ran head-injured patients down to about 32°C and HIE Neonates down to 27°C. This is in controlled conditions, with the benefit of sedative and paralysing agents and sometimes hourly monitoring of blood electrolytes.
To say that a patient running at 37°C is hypothermic is blatantly wrong regardless of the writers bibliography or how many letters they have after their name. Contrary to some comments on this thread, checking core temperature in the field is not problematic and mountain rescue teams do it all the time. The most common methods are sub-lingual and axillary. Tympanic measurements are not reliable in a field context, and rectal is just unnecessary.
To start treating a casualty with a core temperature of 36°C as suffering from primary hypothermia, and ignoring the possibilities of, for example: MI, CVA or diabetic coma would be extremely dangerous and could kill your casualty - that's why this conversation is so important.
To say that a patient running at 37°C is hypothermic is blatantly wrong regardless of the writers bibliography or how many letters they have after their name. Contrary to some comments on this thread, checking core temperature in the field is not problematic and mountain rescue teams do it all the time. The most common methods are sub-lingual and axillary. Tympanic measurements are not reliable in a field context, and rectal is just unnecessary.
To start treating a casualty with a core temperature of 36°C as suffering from primary hypothermia, and ignoring the possibilities of, for example: MI, CVA or diabetic coma would be extremely dangerous and could kill your casualty - that's why this conversation is so important.
I've edited two paragraphs of my article. Please let me know what you think.
The aim of my article was to help people avoid hypothermia, deal with someone who is mildly to moderately hypothermic and realise the limitations of what they can achieve without external medical asstance. For outdoors people, avoidance is arguably the most important skill.
For your typical hiker, taking core temperatures is still impractical. They won't have the necessary equipment for starters. Yes, I know it's easy to carry Tempa-dots in your first aid kit for instance. It's then easy to take sub-lingual temperatures. Most people, however, only have very basic first aid kits. There are also reported issues with taking sub-lingual temperatures such as written about here http://www.bmj.com/content/1/5960/718.abstract This is an old paper though, so I'd be interested to hear Martyn and Ronnie's opinion of the accuracy of sub-lingual temperatures in the field.
Of course if you were to come across an unconscious casualty, you should consider all the potential causes of unconsciousness. It would be ridiculous to suggest otherwise. As I stated in my article "If the casualty is unconscious then you should prioritise as per the basic life support protocols from your first aid training".
I wrote my article to help people enjoy the outdoors more safely. I think it does this. Thanks to Martyn and Ronnie for their input and helping me improve it further.
All the best
Paul
The aim of my article was to help people avoid hypothermia, deal with someone who is mildly to moderately hypothermic and realise the limitations of what they can achieve without external medical asstance. For outdoors people, avoidance is arguably the most important skill.
For your typical hiker, taking core temperatures is still impractical. They won't have the necessary equipment for starters. Yes, I know it's easy to carry Tempa-dots in your first aid kit for instance. It's then easy to take sub-lingual temperatures. Most people, however, only have very basic first aid kits. There are also reported issues with taking sub-lingual temperatures such as written about here http://www.bmj.com/content/1/5960/718.abstract This is an old paper though, so I'd be interested to hear Martyn and Ronnie's opinion of the accuracy of sub-lingual temperatures in the field.
Of course if you were to come across an unconscious casualty, you should consider all the potential causes of unconsciousness. It would be ridiculous to suggest otherwise. As I stated in my article "If the casualty is unconscious then you should prioritise as per the basic life support protocols from your first aid training".
I wrote my article to help people enjoy the outdoors more safely. I think it does this. Thanks to Martyn and Ronnie for their input and helping me improve it further.
All the best
Paul
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Hi,
I appreciate why you have this discussion but it seems to me there are two approaches emerging:
- one for the average hiker (no medical background, limited equipment, in need of simple strategies to cover most cases)
- one for medical professionals
I guess it is fine to have both but my concenr would be to obfuscate the 'simple & practical message' with more - valid but complex - details. What I would like to hear from Martyn and other pros is what they would recommend to the average hiker in complement or different from what Paul explained.
I appreciate why you have this discussion but it seems to me there are two approaches emerging:
- one for the average hiker (no medical background, limited equipment, in need of simple strategies to cover most cases)
- one for medical professionals
I guess it is fine to have both but my concenr would be to obfuscate the 'simple & practical message' with more - valid but complex - details. What I would like to hear from Martyn and other pros is what they would recommend to the average hiker in complement or different from what Paul explained.
Thanks for the edit, Paul. It's a small but important change. Some useful data here:
http://www.wemjournal.org/article/S1080-6032(96)70989-4/abstract - full text is downloadable from there in *.pdf format.
I also found this re active warming which looked quite handy - it's from 2001 though and has the old ABC approach so may have been superceded:
http://www.wemjournal.org/article/S1080-6032(96)70989-4/abstract - full text is downloadable from there in *.pdf format.
I also found this re active warming which looked quite handy - it's from 2001 though and has the old ABC approach so may have been superceded:
Hey Ronnie, thanks for link. The additional information is useful. The flow-chart is does look handy but, as you say, it would be good to know if it has been superceded.
All the best
Paul
All the best
Paul
D
DarkHorse
Guest
The latest research into hypothermia shows that warming the extremities has the best effect. I saw a discovery channelt program where this guy went into icy water and came out and is body temp was raised by wearing "heated gloves". I think this is a really awesome idea and should save lots of lives.
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