It's hard to be thinking about mosquitos during the first lake effect event of the season, but maybe it will get you into the mood for summer!
For a long time, I have endorsed the usual understanding of the mechanism by which mosquitos target warm-blooded animals. For quite a while, it has been recognized that there is a complex neurochemical mechanism by which the bugs are attracted to carbon dioxide. From an evolutionary standpoint, this makes a lot of sense: if you are looking for a blood meal, what better way to find it than by going after something which breathes out carbon dioxide? It is also consistent with our backcountry observations. How many times, for example, have you noticed the propensity of these creatures to congregate under the tent fly?
This understanding has also permitted me to pooh-pooh students in my classes who claim that something about their own sweat, soap, or BO is particularly attractive to mosquitos. I have generally dismissed them as whiners, and pontificated that there was no biologic mechanism for such an observation. How could a bug distinguish between Dr. Bronner's and Mountain Suds?
Mea culpa.
Complex modern science has now shown us that the smell detection system of mosquitos is vastly more complicated than we ever could have imagined. In the process, it has also uncovered the biologic explanation for the effectiveness of DEET. Pretty impressive.
The study (by Liu and associates at Vanderbilt) is available online from the journal PLoS Biology (http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000467). The molecular biology here is daunting, and not for the faint of heart. Also keep in mind that the work was done with an African mosquito; it is certainly plausible, however, that similar mechanisms are in place for other species.
These scientists have unraveled the existence of two distinct olfactory signaling pathways in these insects. Each of these pathways (AgOR and AgIR) consists of a family of specific receptors, each of which, presumably, can respond to specific odors. Such responses can be either attractive or repulsive. A specific receptor (AgOR7) appears to be the actual target of DEET; animals in whom this receptor was inactivated by microinjection of specific RNA fragments were no longer affected by DEET.
What can we take away from this elegant science? Carbon dioxide is still a potent attractant for mosquitos, but short of stopping breathing there is nothing we can do about it. DEET works--we know this from a lot of previous behavioral studies, and now we understand it at the molecular level. From a wealth of other studies, we also know that the health concerns of DEET are vastly overblown and can generally be ignored. Mosquitos also seem to be capable of responding to a lot of other olfactory stimuli, but we do not as yet understand what makes something attractive or repulsive.
Bottom line--it is now plausible that certain individuals are more attractive to mosquitos than others. Other than DEET and protective garmets, however, there is little to do other than sucking it up!
Thursday, December 2, 2010
Wednesday, October 13, 2010
How much "risk" can we tolerate in the wilderness?
This topic comes up a lot among wilderness educators, but I recently came across two seemingly unrelated pieces in the New York Times which provide a very nice context to the discussion.
The first (http://www.nytimes.com/2010/08/27/us/27cuts.html?_r=1&scp=3&sq=fire%20departments&st=cse) describes the angst which is developing in a number of urban areas as budget constraints are challenging city fire and EMS services. The article begins with the tragic story of a two-year-old boy in San Diego who suffered a fatal aspiration at his home. Although there was a fire station near the home, staffing changes in the SDFD led to its being empty at the time of the incident. The police responded to the child's home within five minutes and started CPR, but it took 9 and a half minutes for an ambulance to arrive. The child was pronounced dead at the hospital.
The first (http://www.nytimes.com/2010/08/27/us/27cuts.html?_r=1&scp=3&sq=fire%20departments&st=cse) describes the angst which is developing in a number of urban areas as budget constraints are challenging city fire and EMS services. The article begins with the tragic story of a two-year-old boy in San Diego who suffered a fatal aspiration at his home. Although there was a fire station near the home, staffing changes in the SDFD led to its being empty at the time of the incident. The police responded to the child's home within five minutes and started CPR, but it took 9 and a half minutes for an ambulance to arrive. The child was pronounced dead at the hospital.
Although it is not clear to me that the child would have survived with earlier care (when children survive such incidents, it is almost always because of immediate bystander intervention), the implication of the article was that harm may have been done because the city could not meet up to the "national goal" of a five minute response.
Well, just a minute here.
I am writing this entry at our summer home in the Adirondacks. I probably couldn't get my nearest neighbor here within five minutes. The nearest fire department with EMS service is in a town about 16 miles away, and that is a volunteer operation. Ten times the "national goal" would actually be a pretty good response to our place!
Mind you, this area is by no means "wilderness". There are several hundred homes in the vicinity, with such important services as bars, a gas station, pizza joints, and even a (limited hours) vet clinic. Although we are seasonal users, there are plenty of year-round residents. If any of my neighbors are disturbed that our access to emergency medical services is way outside the national goal, I haven't heard it from them. Indeed, nearly every edition of the local weekly (we also have a paper) carries a letter to the editor thanking the volunteer ambulance crews for something!
Folks who choose to live (or get away) in places such as this generally make very informed decisions. No--we can't call a cab. No--we may not be able to have high-speed internet access. No--if the big one comes some evening, we will not be defibrillated within minutes. On the other hand, we are not awakened by sirens at night, the smells of balsam replace those of exhaust, and we don't worry about walking in the neighborhood. There are plenty of folks living throughout the US in very similar circumstances, and I doubt that many would trade them in order to be assured of a more rapid EMS response.
How does this apply to the wilderness? Just like the person who moves from San Diego, CA to Woodgate, NY is accepting a change in the availability of assistance in emergencies, the user of the wilderness is (or should be) doing so to an even greater degree. Stepping into the backcountry is an experience of inestimable value. It has a downside. The likelihood of surviving major trauma deep in the Five Ponds Wilderness is nil. An identical injury on 42nd Street and 8th Avenue might well be survivable. Sadly, one just can't have it both ways. Take your pick.
This ethic extends to situations well beyond major trauma. Sprain your ankle at the tennis club, and expect your buddy to drive you home and share a beer with you after helping you get some ice. Sprain it on the way down Katahdin and you should expect a pretty rough time; please don't expect a helicopter ride to Bangor. One of my many complaints about the "WFR" movement is that it may contribute to the perception that there is really something which can be done for devastating injury or illness is very remote areas. Usually, there isn't. Accept it.
Which brings me to the other article: http://www.nytimes.com/2010/08/27/opinion/27stroll.html?_r=1&scp=5&sq=wilderness&st=nyt.
This opinion piece, by an attorney, decries the US Forest Service for lack of signage in some wilderness areas, bemoaning the occasonal camper, hiker, or hunter who becomes lost. If one wishes to hike on established and well marked trails, the options in North America are nearly limitless. Yet, if one wants to test the extent of his navigational and wilderness skills in an expansive, truly "unmarked" environment, options in the lower 48 are not many. Indeed, when I teach such skills, I prefer to do so in Alaska. We do not seem to care that a number of skiers choosing black diamond routes will sustain serious, indeed some life-threatening injuries. Why can we not allow the wilderness equivalent of "black diamond" for those of us who desire such experiences?
Backpacking and similar wilderness pursuits, in virtually every database, are extraordinarily safe. Yet, they carry inherent risks which simply cannot be eliminated without significantly devaluing the experience. By giving the impression that we can "manage" these risks out of existence, we do harm in two ways. We provide expectations of safety which cannot be realized. We invite regulatory interventions which ultimately destroy the experiences that we value.
Monday, August 16, 2010
Wilderness Helicopter Evacuations
This has not been a good summer for the medical helicopter industry, or its employees and patients. Crashes in July took the lives of three in Arizona and two in Oklahoma; these brought to four the number of fatal medical helicopter crashes in 2010 alone.
Fortunately, none of these crashes involved wilderness rescues. On the other hand, it is simply a matter of time before a catastrophic incident occurs in the backcountry.
There has been a proliferation in the use of helicopters to provide medical response to wilderness injuries and illnesses in the past few years. Indeed, in this month alone, two such responses occured in the New York Adirondacks. While there may certainly be circumstances in which such an undertaking could be lifesaving, there are others in which this response has been mobilized for a condition which turned out to be trivial. Folks have undergone helicopter evacuations for sprained ankles, broken arms, and similar mishaps which in an earlier time would have been handled with an uncomfortable, but safer, "walk-out". The US Forest Service even dispatched a helicopter to "rescue" two workers who were freaked out by the sounds of wolves howling: http://www.mtexpress.com/index2.php?ID=2005112785
The Federal Aviation Administration has recently (June 8, 2010) recognized medical helicopters as an industry meriting closer regulation and scrutiny. Their fact sheet highlights (without explicitly addressing wilderness use) one of the vulnerabilities in the backcountry setting. The decision to mobilize a helicopter medical mission actually requires the decision of two professionals. First, a medical person (typically on the scene) makes the determination that air evacuation is necessary. Secondly, the pilot makes the determination that the mission is safe.
In urban settings, the first of these decisions is often (although not always) made by individuals with medical training and experience: EMTs, emergency physicians, etc. The system in the backcountry, however, is far less formal. The call for a helicopter rescue may well be initiated by an individual on the scene with minimal training and experience in the assessment of injuries. While one might argue that "when in doubt, err on the side of safety", the above experiences suggest that it is hardly a given that "safety" is served by dispatching a helicopter into wilderness terrain.
This is obviously a very controversial subject, and it currently is informed by very little data and lots of anecdote. With a colleague, I am currently embarking on a study of medical helicopter evacuations in a wilderness area which will include actual disposition of the evacuees--some of the anecdote to which I allude suggests that it is not uncommon for individuals flown out of the woods to be evaluated in the hospital and sent home without admission. When complete, the data from this study may help us develop a more structured process for mobilizing this high-tech and potentially deadly resource in the wilderness.
Fortunately, none of these crashes involved wilderness rescues. On the other hand, it is simply a matter of time before a catastrophic incident occurs in the backcountry.
There has been a proliferation in the use of helicopters to provide medical response to wilderness injuries and illnesses in the past few years. Indeed, in this month alone, two such responses occured in the New York Adirondacks. While there may certainly be circumstances in which such an undertaking could be lifesaving, there are others in which this response has been mobilized for a condition which turned out to be trivial. Folks have undergone helicopter evacuations for sprained ankles, broken arms, and similar mishaps which in an earlier time would have been handled with an uncomfortable, but safer, "walk-out". The US Forest Service even dispatched a helicopter to "rescue" two workers who were freaked out by the sounds of wolves howling: http://www.mtexpress.com/index2.php?ID=2005112785
The Federal Aviation Administration has recently (June 8, 2010) recognized medical helicopters as an industry meriting closer regulation and scrutiny. Their fact sheet highlights (without explicitly addressing wilderness use) one of the vulnerabilities in the backcountry setting. The decision to mobilize a helicopter medical mission actually requires the decision of two professionals. First, a medical person (typically on the scene) makes the determination that air evacuation is necessary. Secondly, the pilot makes the determination that the mission is safe.
In urban settings, the first of these decisions is often (although not always) made by individuals with medical training and experience: EMTs, emergency physicians, etc. The system in the backcountry, however, is far less formal. The call for a helicopter rescue may well be initiated by an individual on the scene with minimal training and experience in the assessment of injuries. While one might argue that "when in doubt, err on the side of safety", the above experiences suggest that it is hardly a given that "safety" is served by dispatching a helicopter into wilderness terrain.
This is obviously a very controversial subject, and it currently is informed by very little data and lots of anecdote. With a colleague, I am currently embarking on a study of medical helicopter evacuations in a wilderness area which will include actual disposition of the evacuees--some of the anecdote to which I allude suggests that it is not uncommon for individuals flown out of the woods to be evaluated in the hospital and sent home without admission. When complete, the data from this study may help us develop a more structured process for mobilizing this high-tech and potentially deadly resource in the wilderness.
Tuesday, May 18, 2010
The dark side of Epi Pens
The Journal of Allergy and Clinical Immunology is probably not on the "must read" list for most of the wilderness medicine crowd, but an article in the current issue (2010; 125:419-423) merits careful study. This report queried two databases, the American Association of Poison Control Centers and the Food and Drug Administration's Adverse Event Reporting System, to determine whether there has been a significant number of unintentional injections from these devices.
This is not a trivial question. With increasing recognition of the severe allergic reaction called "anaphylaxis", physicians have been prescribing automated epinephrine injectors ("Epi Pens") to many patients so that they can begin emergency treatment themselves after an unanticipated exposure to an allergic trigger. Having at risk individuals (or the parents/caretakers of at risk children) being trained and carrying Epi Pens is an important component of good health care, and should continue to be encouraged. As Epi Pens become more and more common, however, it is important to study whether there have been any unintended consequences of this availablity.
The answer from this study is an unequivocal "yes". Over the thirteen year period spanning 1994 to 2007, there were 15,190 reports of unintentional injections from automated epinephrine injectors. You read that number correctly--over fifteen thousand. These numbers are trending upward, with more than half occuring in the last four years. The nature of these reports was such that fine details of the incidents were not available, although nearly a third of them required evaluation in a hospital or other health care setting. We know from other published reports that very severe complications have been reported from such inadvertent administration, including the need for amputations.
How do these incidents occur? Again, the detail in the study is not exhaustive, but included were accidental firing, mishaps during training, and accidental injection while reaching into a bag or purse.
Why should this matter in the wilderness or outdoor recreation industry? Most of us have had or will have the experience of a participant with a history of insect anaphylaxis coming to a program with a personal Epi Pen. The standard of care here is pretty straightforward in such a situation. Be aware of the specifics and where the client is keeping the device (a second device in the backcountry setting is appropriate); practice primary prevention by assiduously working to avoid exposures to the offending antigens; in the event of an actual exposure, assist the client in locating and using his device. In the event that the client is incapacitated and unable to activate her injector, be prepared to do so. Since the vast majority of outdoor professionals do not handle needles on a regular basis, be extremely careful not to become counted in a series of inadvertant administrations!
I wish that the whole thing were as simple as this. Sadly, it is not. For reasons that I do not understand, there has been a push by many in the outdoor/wilderness education community to encourage the wider availability of Epi Pens, beyond their intended prescription to patients with a medical diagnosis of susceptibility to anaphylaxis for their personal use. Some have opined that Epi Pens should become part of the regular first aid supplies for backcountry treks, challenge courses, and similar programs. The outdoor educator (presumably with the imprimatur provided by WFR or similar certification), would then be empowered to make the diagnosis of anaphylaxis in someone with no previous diagnosis, and provide an injection of epinephrine. Some in the WFR community have even been advocating for changes in law to permit this practice, believing that not doing so may be dooming some unfortunate participant in one of our programs to needless death. How could anyone object?
I'll tell you how.
First of all, let's put this problem into perspective. Although the data are a bit soft, the number of individuals in the US dying annually from anaphylaxis caused by insect (mostly Hymenoptera) stings is about 100. About the same number die from lightening, and twice as many die in floods each year. The risk of dying from food poisoning in the US is fifty-times that of insect anaphylaxis and the flu kills between 300 and 400 times as many individuals. So.... While it is obviously a devastating problem when it happens, it is extraordinarily rare and pales in comparison to a host of daily threats to life and limb. I have yet to hear of a well-documented death from insect anaphylaxis in the back country--I don't deny that it may have happened to someone, somewhere; I simply have seen no convincing evidence of it. Yet, despite this rarity, folks seem to believe it necessary and appropriate for any backcountry trek to be "protected" by the presence of an Epi Pen and someone willing to employ it.
Other than the documented risk of accidental injury from the device, could anyone be injured by "intentional misuse"? In other words, could any harm come to someone with a breathing problem other than anaphylaxis to whom a well-intentioned layperson administered epinephrine?
You bet it could.
The problems which can result in sudden "breathing emergencies" are numerous, and include things like choking/aspiration, acute pulmonary edema, asthma, pneumonia/pneumonitis, primary cardiac disease, dehydration/acidosis, anxiety, and many more. While those of us who deal with such things on a daily basis can generally pick up on the nuances which distinguish some of these from others, this is not easy for someone who is not regularly assessing such patients. Regardless of cause, breathing emergencies tend to be very dramatic and, frankly, scary. Being suddenly confronted with someone gasping, short of breath, and severely panicked can be terrifying to the uninitiated--and an hour or two of classroom instruction hardly qualifies as "initiation". In such a setting, the tendency to "do something" is powerful, and if an Epi Pen is readily available, it may well be used. If the problem is not anaphylaxis (or, perhaps, asthma), the drug will either do nothing or make things much worse. In particular, an anxiety reaction (which can produce dramatic respiratory symptoms) will be severely worsened by the administration of epinephrine.
Carrying Epi Pens has now been shown to entail a real risk of injury. Using them inappropriately can significantly worsen a number of conditions which could be confused with anaphylaxis. Fatalities from insect-related anaphylaxis are extraordinarily rare. In light of these facts, it is inexplicable that outdoor educators continue to fret so much about the need for them to have ready access to these devices. It is hard to see this preoccupation as a sincere, informed desire to improve health and save lives. If that were the motivation, I would expect to see a lot more attention being devoted to things like pre-trek influenza immunization or expedition food safety--serious health issues which are vastly more common than anaphylaxis.
Of course, it is cool to carry an injectable drug in one's backcountry first aid kit!
This is not a trivial question. With increasing recognition of the severe allergic reaction called "anaphylaxis", physicians have been prescribing automated epinephrine injectors ("Epi Pens") to many patients so that they can begin emergency treatment themselves after an unanticipated exposure to an allergic trigger. Having at risk individuals (or the parents/caretakers of at risk children) being trained and carrying Epi Pens is an important component of good health care, and should continue to be encouraged. As Epi Pens become more and more common, however, it is important to study whether there have been any unintended consequences of this availablity.
The answer from this study is an unequivocal "yes". Over the thirteen year period spanning 1994 to 2007, there were 15,190 reports of unintentional injections from automated epinephrine injectors. You read that number correctly--over fifteen thousand. These numbers are trending upward, with more than half occuring in the last four years. The nature of these reports was such that fine details of the incidents were not available, although nearly a third of them required evaluation in a hospital or other health care setting. We know from other published reports that very severe complications have been reported from such inadvertent administration, including the need for amputations.
How do these incidents occur? Again, the detail in the study is not exhaustive, but included were accidental firing, mishaps during training, and accidental injection while reaching into a bag or purse.
Why should this matter in the wilderness or outdoor recreation industry? Most of us have had or will have the experience of a participant with a history of insect anaphylaxis coming to a program with a personal Epi Pen. The standard of care here is pretty straightforward in such a situation. Be aware of the specifics and where the client is keeping the device (a second device in the backcountry setting is appropriate); practice primary prevention by assiduously working to avoid exposures to the offending antigens; in the event of an actual exposure, assist the client in locating and using his device. In the event that the client is incapacitated and unable to activate her injector, be prepared to do so. Since the vast majority of outdoor professionals do not handle needles on a regular basis, be extremely careful not to become counted in a series of inadvertant administrations!
I wish that the whole thing were as simple as this. Sadly, it is not. For reasons that I do not understand, there has been a push by many in the outdoor/wilderness education community to encourage the wider availability of Epi Pens, beyond their intended prescription to patients with a medical diagnosis of susceptibility to anaphylaxis for their personal use. Some have opined that Epi Pens should become part of the regular first aid supplies for backcountry treks, challenge courses, and similar programs. The outdoor educator (presumably with the imprimatur provided by WFR or similar certification), would then be empowered to make the diagnosis of anaphylaxis in someone with no previous diagnosis, and provide an injection of epinephrine. Some in the WFR community have even been advocating for changes in law to permit this practice, believing that not doing so may be dooming some unfortunate participant in one of our programs to needless death. How could anyone object?
I'll tell you how.
First of all, let's put this problem into perspective. Although the data are a bit soft, the number of individuals in the US dying annually from anaphylaxis caused by insect (mostly Hymenoptera) stings is about 100. About the same number die from lightening, and twice as many die in floods each year. The risk of dying from food poisoning in the US is fifty-times that of insect anaphylaxis and the flu kills between 300 and 400 times as many individuals. So.... While it is obviously a devastating problem when it happens, it is extraordinarily rare and pales in comparison to a host of daily threats to life and limb. I have yet to hear of a well-documented death from insect anaphylaxis in the back country--I don't deny that it may have happened to someone, somewhere; I simply have seen no convincing evidence of it. Yet, despite this rarity, folks seem to believe it necessary and appropriate for any backcountry trek to be "protected" by the presence of an Epi Pen and someone willing to employ it.
Other than the documented risk of accidental injury from the device, could anyone be injured by "intentional misuse"? In other words, could any harm come to someone with a breathing problem other than anaphylaxis to whom a well-intentioned layperson administered epinephrine?
You bet it could.
The problems which can result in sudden "breathing emergencies" are numerous, and include things like choking/aspiration, acute pulmonary edema, asthma, pneumonia/pneumonitis, primary cardiac disease, dehydration/acidosis, anxiety, and many more. While those of us who deal with such things on a daily basis can generally pick up on the nuances which distinguish some of these from others, this is not easy for someone who is not regularly assessing such patients. Regardless of cause, breathing emergencies tend to be very dramatic and, frankly, scary. Being suddenly confronted with someone gasping, short of breath, and severely panicked can be terrifying to the uninitiated--and an hour or two of classroom instruction hardly qualifies as "initiation". In such a setting, the tendency to "do something" is powerful, and if an Epi Pen is readily available, it may well be used. If the problem is not anaphylaxis (or, perhaps, asthma), the drug will either do nothing or make things much worse. In particular, an anxiety reaction (which can produce dramatic respiratory symptoms) will be severely worsened by the administration of epinephrine.
Carrying Epi Pens has now been shown to entail a real risk of injury. Using them inappropriately can significantly worsen a number of conditions which could be confused with anaphylaxis. Fatalities from insect-related anaphylaxis are extraordinarily rare. In light of these facts, it is inexplicable that outdoor educators continue to fret so much about the need for them to have ready access to these devices. It is hard to see this preoccupation as a sincere, informed desire to improve health and save lives. If that were the motivation, I would expect to see a lot more attention being devoted to things like pre-trek influenza immunization or expedition food safety--serious health issues which are vastly more common than anaphylaxis.
Of course, it is cool to carry an injectable drug in one's backcountry first aid kit!
Friday, May 7, 2010
Packs and Strokes
The health problems which confront backpackers are rarely consequential, and certainly less important than the overall very positive impact on health which spending time in the wilderness conveys. Every now and then, however, something potentially serious comes up. Ignoring signs of trouble in the front country can be dangerous, but the rapid availablity of emergency medical services may compensate for earlier delays. The back country, however, is far less forgiving.
I was reminded of this the other day, upon reading and responding to a question posed by a visitor to my website. This gentleman was on a hike in the northeast when he began to experience some tingling and weakness of one arm, accompanied by facial weakness and slurring of speech; fortunately, this resolved on its own over a few minutes. Nonetheless, he rightly worred about this, headed out, and spent some time in a hospital. In retrospect, he wondered if all of this could have been caused by too-tight backpack straps.
The quick answer to his question was "of course not". These sudden changes in his neurologic status could have represented a stroke; the fact that they resolved within minutes defined them as a "mini stroke" or transient ischemic attack (TIA). If it had been the start of an actual stroke, he would have had a very narrow time window of opportunity to receive a therapy which could prevent or minimize the develoment of long-term disability. In fact, this time window is so short I believe that a "walk out" evacuation (assuming the group is within an hour or so of a trail head and the individual is stable enough to walk) is preferable to staying put and sending for help.
The notion that this could have been caused by pack straps, however, is not unreasonable. I have written extensively about this in an article on this website. Go to the "publications" link and find the article curiously entitled "On numbness and tingling". Pressure of straps from a backpack on the nerves supplying the arms frequently causes numbness and tingling. This almost always occurs in both arms, however, and should never be accompanied by speech problems, facial weakness, or other features.
For more information on the recognition and emergency treatment of stroke, visit the American Heart Association website: http://www.strokeassociation.org/presenter.jhtml?identifier=1020.
I was reminded of this the other day, upon reading and responding to a question posed by a visitor to my website. This gentleman was on a hike in the northeast when he began to experience some tingling and weakness of one arm, accompanied by facial weakness and slurring of speech; fortunately, this resolved on its own over a few minutes. Nonetheless, he rightly worred about this, headed out, and spent some time in a hospital. In retrospect, he wondered if all of this could have been caused by too-tight backpack straps.
The quick answer to his question was "of course not". These sudden changes in his neurologic status could have represented a stroke; the fact that they resolved within minutes defined them as a "mini stroke" or transient ischemic attack (TIA). If it had been the start of an actual stroke, he would have had a very narrow time window of opportunity to receive a therapy which could prevent or minimize the develoment of long-term disability. In fact, this time window is so short I believe that a "walk out" evacuation (assuming the group is within an hour or so of a trail head and the individual is stable enough to walk) is preferable to staying put and sending for help.
The notion that this could have been caused by pack straps, however, is not unreasonable. I have written extensively about this in an article on this website. Go to the "publications" link and find the article curiously entitled "On numbness and tingling". Pressure of straps from a backpack on the nerves supplying the arms frequently causes numbness and tingling. This almost always occurs in both arms, however, and should never be accompanied by speech problems, facial weakness, or other features.
For more information on the recognition and emergency treatment of stroke, visit the American Heart Association website: http://www.strokeassociation.org/presenter.jhtml?identifier=1020.
Tuesday, April 27, 2010
Water, water everywhere....
I was thinking about this Coleridge quote the other day, after my friend Tod Schimelpfenig from NOLS let me know about a recent "near miss" involving a solo hiker in New Mexico. The whole story is reported in an article in the Silver City Sun News (http://www.scsun-news.com/ci_13848541).
Basically, this is the tale of a chap who nearly lost his life because of bad information from the outdoor education industry. He became lost, and subsequently seriously dehydrated, ultimately requiring a search and rescue operation. The irony of the story is that he was lost while hiking around a river. How, you may ask, can one become "dehydrated" near a river? His trusty water filter wasn't working properly, and he was unable to boil sufficient water to obtain enough to drink. Of course, he could have just stuck his face in the river and gulped down several mouths-full, but apparently he was afraid of contracting some horrible disease by doing so! This poor guy had been so indoctrinated by the spurious teachings regarding wilderness water safety that he allowed himself to become dehydrated while surrounded by fresh water!
Anyone who has followed my writings on this subject should know my take on the "contaminated water" nonsense. There has never been one iota of real data suggesting that North American wilderness waters are unsafe for consumption. Most of this hysteria has come from a mid-seventies incident in Utah, which modern information suggests was most likely an illness within a camping group spread by poor personal hygiene. Well-documented reports of individual hikers contracting illness by consuming backcountry water are nonexistent, and most experts today are recognizing the vastly more important role of group hygiene in preventing intestinal illness. The "publications" link on my website will take you both to some technical and some lay articles discussing this in more detail.
Why is the tale of Mr. Mason's near-fatal hike important? It provides an answer to the occasional wilderness educator who agrees that the risk of drinking untreated water is trivial, but still opines that advocating universal treatment "can't hurt". Well, it sure can if the message taken home by folks like Mr. Mason is that there is still a chance of danger!
Finally, there is another curious item in the article describing this incident. Apparently, some undoubtedly well-meaning rescuers provided Mr. Mason with some intravenous fluid for his dehydration. This, no doubt, will bring a smile to the faces of the "wilderness first responder" education industry. Indeed--this poor guy would have perished without the advanced medical know-how with which he was provided at the scene! Hold your applause. Short of unconsciousness or severe vomiting, dehydration can be treated quite adequately (perhaps even more safely) with oral fluids. The World Health Organization has shown dramatically that oral salt and water can revive near-moribund victims of dehydration. The treatment Mr. Mason needed was nothing more complicated than good, clear river water, supplemented by some salty snacks! The outdoor education/wilderness medicine industry may have gotten this poor guy into this mess, and could have complicated getting him out.
Basically, this is the tale of a chap who nearly lost his life because of bad information from the outdoor education industry. He became lost, and subsequently seriously dehydrated, ultimately requiring a search and rescue operation. The irony of the story is that he was lost while hiking around a river. How, you may ask, can one become "dehydrated" near a river? His trusty water filter wasn't working properly, and he was unable to boil sufficient water to obtain enough to drink. Of course, he could have just stuck his face in the river and gulped down several mouths-full, but apparently he was afraid of contracting some horrible disease by doing so! This poor guy had been so indoctrinated by the spurious teachings regarding wilderness water safety that he allowed himself to become dehydrated while surrounded by fresh water!
Anyone who has followed my writings on this subject should know my take on the "contaminated water" nonsense. There has never been one iota of real data suggesting that North American wilderness waters are unsafe for consumption. Most of this hysteria has come from a mid-seventies incident in Utah, which modern information suggests was most likely an illness within a camping group spread by poor personal hygiene. Well-documented reports of individual hikers contracting illness by consuming backcountry water are nonexistent, and most experts today are recognizing the vastly more important role of group hygiene in preventing intestinal illness. The "publications" link on my website will take you both to some technical and some lay articles discussing this in more detail.
Why is the tale of Mr. Mason's near-fatal hike important? It provides an answer to the occasional wilderness educator who agrees that the risk of drinking untreated water is trivial, but still opines that advocating universal treatment "can't hurt". Well, it sure can if the message taken home by folks like Mr. Mason is that there is still a chance of danger!
Finally, there is another curious item in the article describing this incident. Apparently, some undoubtedly well-meaning rescuers provided Mr. Mason with some intravenous fluid for his dehydration. This, no doubt, will bring a smile to the faces of the "wilderness first responder" education industry. Indeed--this poor guy would have perished without the advanced medical know-how with which he was provided at the scene! Hold your applause. Short of unconsciousness or severe vomiting, dehydration can be treated quite adequately (perhaps even more safely) with oral fluids. The World Health Organization has shown dramatically that oral salt and water can revive near-moribund victims of dehydration. The treatment Mr. Mason needed was nothing more complicated than good, clear river water, supplemented by some salty snacks! The outdoor education/wilderness medicine industry may have gotten this poor guy into this mess, and could have complicated getting him out.
Saturday, March 27, 2010
Wilderness First Responder Courses
This past Fall, I was invited to participate in a workshop at the annual AORE (Association of Outdoor Recreation Education) conference addressing the increasingly controversial matter of first aid training for wilderness leaders. The workshop was spurred by my recent publication on the topic in Wilderness and Environmental Medicine (available through the "publications" link on my website).
To say that this topic is "controversial" would be an understatement, although the controversy is really not informed by much data. For the providers of wilderness experiences, especially those based in non-profits such as universities, the costs of maintaining WFR certification for their leaders are not trivial. For the providers of WFR training, such courses are truly their lifeblood, supporting what is becoming a huge industry.
The workshop included several of the major providers of WFR training programs, all of whom are fine individuals who clearly are passionate about their mission and believe that they are providing a vital service. Similarly, the SRO groups from college and university wilderness programs were mindful of the costs but anxious to be sure that they were doing the right thing for their participants.
Good intentions notwithstanding, the discussion at this workshop convinced me even more that the wilderness "medicine" education industry is very much overdue for significant scrutiny. For example, all of the providers present acknowledged that there were absolutely no data speaking to the meaningful retention of any of the competencies taught in such courses. There are ample reasons to question this, many of which we addressed in the publication referenced above. The vast majority of folks taking WFR courses are not operating in the medical field in their daily work, and epidemiologic data are quite clear that their exposure to medical problems in the course of their wilderness work is actually very minimal. We know from studies of layperson competency in CPR skills that retention of such material by those not using it is negligible. If a reasonably structured, basic skill such as CPR cannot be meaningfully retained by laypersons, one has to wonder about the vast number of "protocols" being thrust upon them in the course of a typical WFR program!
Beyond the retention issue, the matter of the skills themselves has never been carefully examined. For example, much was made during the discussion phase of the workshop regarding the various "asthma protocols" taught by the many providers. Most of these are little more than common sense, with the addition of some recommendations regarding the use of asthma inhalers or injectable epinephrine. Use of the latter without prescription, of course, is outside the "scope of practice" of any WFR provider operating outside the framework of an established EMS system, and is illegal in every jurisdiction in the United States. Beyond this, however, any client with asthma which is being treated according to acceptable standards in the US today should have an "asthma action plan", which details precisely the indications for use and acceleration of medications during an episode. Use of such plans, which are vastly more sophisticated and personalized than some random WFR "asthma protocol", should be the basis of any approach to a client having difficulty with his or her asthma. Amazingly, none of the providers of WFR training participating in the workshop had heard of this concept, including one who had asthma himself and seemed quite proud at not having his own asthma action plan!
Rather than devoting time during a WFR course to memorizing some esoteric pulmonary physiology, which will almost assuredly be forgotten the next day, how much better to teach about asthma action plans, and the need in the pre-trek medical screening process to insure that clients with asthma have updated plans and have reviewed the coming trek with their providers?
Unspoken explicitly, but clearly present in the room, was a faint antipathy toward the opinon of "doctors" in any of this. Indeed, the opinion seemed to be that front line wilderness experience trumped whatever medical knowledge someone might bring to the table. No one seemed concerned in the least that a group of first aiders with minimal professional oversight could be developing approaches to asthma which ignored the clearly established standards currently being promulgated by groups of physicians who have devoted their professional lives to the disease!
As our study demonstrated, there are currently absolutely no governmental regulatory requirements speaking to the need for specific first aid training for providers of wilderness experiences. The likelihood that this would ever happen is nil. Thus, the only thing which is keeping this unregulated industry going strong is the honest concern by wilderness educators that it is right and necessary. As data gradually demonstrate that this is not the case, WFR programs may gradually be reigned in. In the meantime, the possibility also exists that some will run afoul of state medical practice statutes, something which could hasten the needed reexamination of the industry.
To say that this topic is "controversial" would be an understatement, although the controversy is really not informed by much data. For the providers of wilderness experiences, especially those based in non-profits such as universities, the costs of maintaining WFR certification for their leaders are not trivial. For the providers of WFR training, such courses are truly their lifeblood, supporting what is becoming a huge industry.
The workshop included several of the major providers of WFR training programs, all of whom are fine individuals who clearly are passionate about their mission and believe that they are providing a vital service. Similarly, the SRO groups from college and university wilderness programs were mindful of the costs but anxious to be sure that they were doing the right thing for their participants.
Good intentions notwithstanding, the discussion at this workshop convinced me even more that the wilderness "medicine" education industry is very much overdue for significant scrutiny. For example, all of the providers present acknowledged that there were absolutely no data speaking to the meaningful retention of any of the competencies taught in such courses. There are ample reasons to question this, many of which we addressed in the publication referenced above. The vast majority of folks taking WFR courses are not operating in the medical field in their daily work, and epidemiologic data are quite clear that their exposure to medical problems in the course of their wilderness work is actually very minimal. We know from studies of layperson competency in CPR skills that retention of such material by those not using it is negligible. If a reasonably structured, basic skill such as CPR cannot be meaningfully retained by laypersons, one has to wonder about the vast number of "protocols" being thrust upon them in the course of a typical WFR program!
Beyond the retention issue, the matter of the skills themselves has never been carefully examined. For example, much was made during the discussion phase of the workshop regarding the various "asthma protocols" taught by the many providers. Most of these are little more than common sense, with the addition of some recommendations regarding the use of asthma inhalers or injectable epinephrine. Use of the latter without prescription, of course, is outside the "scope of practice" of any WFR provider operating outside the framework of an established EMS system, and is illegal in every jurisdiction in the United States. Beyond this, however, any client with asthma which is being treated according to acceptable standards in the US today should have an "asthma action plan", which details precisely the indications for use and acceleration of medications during an episode. Use of such plans, which are vastly more sophisticated and personalized than some random WFR "asthma protocol", should be the basis of any approach to a client having difficulty with his or her asthma. Amazingly, none of the providers of WFR training participating in the workshop had heard of this concept, including one who had asthma himself and seemed quite proud at not having his own asthma action plan!
Rather than devoting time during a WFR course to memorizing some esoteric pulmonary physiology, which will almost assuredly be forgotten the next day, how much better to teach about asthma action plans, and the need in the pre-trek medical screening process to insure that clients with asthma have updated plans and have reviewed the coming trek with their providers?
Unspoken explicitly, but clearly present in the room, was a faint antipathy toward the opinon of "doctors" in any of this. Indeed, the opinion seemed to be that front line wilderness experience trumped whatever medical knowledge someone might bring to the table. No one seemed concerned in the least that a group of first aiders with minimal professional oversight could be developing approaches to asthma which ignored the clearly established standards currently being promulgated by groups of physicians who have devoted their professional lives to the disease!
As our study demonstrated, there are currently absolutely no governmental regulatory requirements speaking to the need for specific first aid training for providers of wilderness experiences. The likelihood that this would ever happen is nil. Thus, the only thing which is keeping this unregulated industry going strong is the honest concern by wilderness educators that it is right and necessary. As data gradually demonstrate that this is not the case, WFR programs may gradually be reigned in. In the meantime, the possibility also exists that some will run afoul of state medical practice statutes, something which could hasten the needed reexamination of the industry.
Sunday, February 14, 2010
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