Foot Blisters 2

This is the second post based upon educational sessions and syllabus material presented at the Wilderness Medical Society Annual Meeting & 25th Anniversary held in Snowmass, Colorado from July 25-30, 2008. The first post was a discussion of blister formation and prevention, with expert advice from Dr. Grant S. Lipman of Stanford University. Now, we will learn more from Dr. Lipman about blister management:

Treating a blister as soon as possible reduces complications from further tissue damage or infection. As mentioned in the previous post, a sensation of warmth associated with a “hot spot” is a warning sign for an impending blister. Prompt attention and rapid intervention can halt the abrasive process to prevent progressive blister formation. Options for hot spot treatment include the preventive taping/lubricant measures mentioned or more expensive adhesive/gel pads, such as Band-Aid Blister Block or Blist-O-Ban (the latter scientifically proven to generate less friction than less expensive options such as adherent felt or moleskin).

Blisters deep to a callus should not be drained, as this is a painful and difficult process. These sub-callus blisters quickly refill with fluid after drainage, and the process can introduce bacteria that cause infection. Likewise, blood-filled blisters should be left intact, because of a similar concern for infection.

Any blister with murky fluid, that is draining pus, or which is associated with warm, red skin or red streaking towards the heart may be infected. The blister should be drained and have antibiotic ointment applied, and there should be consideration for the addition of an oral antibiotic.

The best protection for a blister is its own roof. Small intact blisters that are not causing significant discomfort should be left intact. To assist in protecting this roof, a small adhesive bandage or pad can be applied. Be certain to place a first layer of paper tape under any adhesive tape, so you do not inadvertently de-roof the blister when removing the tape.

The pain from a blister is due to pressure on the incompressible fluid trapped between skin layers. As the abrasion and pressure builds, there is further weakening and separation of skin layers and increased potential for rupturing the blister. When a blister opens, raw skin is exposed. If a blister is punctured with a needle and drained, it will often refill within a few hours. If a large hole is made that allows continuous fluid drainage, there is risk for tearing off the roof and leaving a large damaged area.

So, there is no one correct way to manage a blister. For every technique and product mentioned, there are at least several different options. The following blister treatments assume that you must continue on your feet, because resting and “staying off your feet” is not an option.

Basic Blister Treatment (for intact blisters):

1) Cut moleskin (or a basic blister care product) into a donut of diameter ½ inch to 1/3 inch around the blister. The blister should fit inside the hole in the donut.
2) Place a patch of Spenco 2nd Skin in the donut hole directly over the blister.
3) Cover the moleskin donut and patch with benzoin and tape.

Note that this “traditional” moleskin/donut treatment may cause further pressure points either directly under the moleskin or by transferring pressure and subsequent increased friction to the opposite side of the foot.

Basic Blister Draining:

1) Cleanse both the blister skin and a safety pin with an alcohol pad (the diameter of a safety pin is larger than that of a sewing needle to allow continuous drainage, yet not so large as to risk de-roofing the blister).
2) Puncture the blister with the pin at several points at the margin of the blister (generally on the outside of the foot), rather than via one large hole. This will allow natural foot pressure to continually squeeze out fluid, limiting the risk of de-roofing the blister.
3) Gently push out fluid with your fingers.
4) Blot away the expressed fluid.
5) Cover the drained blister with paper tape (protects the blister roof when any other overlying tape is removed).
6) Cover the paper tape with benzoin, then with shaped adhesive tape. All tape should have trimmed and rounded edges to minimize “dog ears” and peeling off.
7) Reaccumulated fluid can be drained through an intact bandage.

Open and Torn Blister Treatment:

1) Using small scissors or another sharp object, carefully de-roof the blister, completely trimming off the dead skin.
2) Place Spenco 2nd Skin on raw skin.
3) Cover the Spenco 2nd Skin with paper tape.
4) Apply a benzoin coating.
5) Cover with Elastikon or another tape product.

Toe Blister:

1) Drain the blister with an alcohol-cleansed safety pin.
2) Use one piece of Micropore tape to encircle the (leaving the torn
tape end at the dorsum of the foot to avoid irritating neighboring toes).
3) Pinch closed the tape.
4) Trim sharp edges or wrinkles in the tape. Avoid cloth tape or Elastikon on the toes, as the abrasive nature of these tape varieties may cause blisters on adjacent toes.

Advanced Blister Care Treatments:

1) One may advance a needle and thread through two sides of a blister, leaving ¼ inch of “tied tails.” The thread wicks away moisture and dries quickly. However, leaving an exit source and a wick in the wound may allow entry of bacteria.
2) De-roof the blister, then pour on Mercurichrome. This may be incredibly painful. This therapy is sometimes controversial, because of issues with pain and tissue toxicity.
3) Inject tincture of benzoin or New-Skin liquid bandage directly into the blister. This seals the blister, but may be incredibly painful.

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Thank You to Rural Doctoring for Grand Rounds

Thank you to Rural Doctoring for including my post about the importance of preserving the wilderness in this week's edition of Grand Rounds. Grand Rounds is a weekly compilation of posts related to health care compiled by a host, who makes a great effort to compile an interesting collection for readers.

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Reading for Pleasure - Into The Wild

In response to my post entitled Mountain Rescue Doctor, a reader comments: "I'd like to hear what other books Dr. Auerbach has enjoyed reading."

I'm going to continue to offer book reviews from time to time. I don't have a tremendous amount of time for "recreational reading," so while some of these books may have been in print for a while, I feel that they would be of interest for readers of this blog. And sometimes, I may not have enjoyed reading them very much - I will let you know when that is the case.

Into the Wild by Jon Krakauer is at times an absorbing tale of a young man's adventure-gone-wrong in Alaska, and at other times a bit of a ramble about the author's perception of the meaning of his own existence. It is well written, because Krakauer is a very good writer, but I found it easy to note the differences in intensity and spirit of the writing when the author moved from his description of Christopher McCandless (moderately intense) to writing about his own experiences (very intense) to providing brief (and comparatively sterile) accounts of other persons whose adventures had gone awry.

The main character is Chris McCandless, a recent college graduate, who abandoned his middle class life of privilege to become a wanderer, ultimately destined to experience solitude and death by starvation in the wilds of Alaska. Krakauer did extensive research about McCandless, his family, and some of the more poignant interactions he had with strangers during his migration across America and up to Alaska. It is more of a personality study than a tale of adventure, because what McCandless essentially accomplished was to walk into the woods, take up residence in an abandoned bus, become stranded and fail to survive because he could not procure adequate food, did not let anyone know where he was, and was not aware that help was within reach had he known where to seek it. It is a sad tale of personal struggle. The deceased had emotional demons, and could not successfully manage them. His family is portrayed in real terms by Krakauer, and I found all of my sympathies with them at the conclusion of the book. McCandless took a partially-educated chance by choosing to rely upon a very basic knowledge of survival, and as much as he, his family and acquaintances paid the price.

When the author draws a parallel between a particular climbing experience of his youth and the activities of McCandless, his writing took on all the nuances and color that I would have liked to see within the rest of the book. It became immediately obvious that the story became as much about Krakauer as about McCandless, and since the author could truly recall his emotions, while he could only hypothesize about the feelings and motivations of McCandless, the writing was richer and more explanatory. Amidst the truisms about the mindset of young men, there are touches of disenfranchisement and narcissism. These are not off-putting, and perhaps demonstrate how a very good writer can bring a reader to a precise place and time.

In the end, it is a case study of a man driven by a certain psychological profile rather than a mystery, tale of exploration, or treatise on self preservation in the wilderness. I actually enjoyed the movie as much as the book, because it stayed the course by focusing only on McCandless. I am a fan of Jon Krakauer and like many other readers have enjoyed Into Thin Air and Under The Banner of Heaven. Into The Wild is a book worth reading, particularly for young men and women who seek to set off on their own into the wilderness for more than a few days. No one is invulnerable, and everyone should be prepared.

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Without the Wilderness, There Can Be No Wilderness Medicine: An Open Letter to the Presidential Candidates

In this 2008 United States presidential campaign, as the two main candidates, Barack Obama and John McCain, are being scrutinized by voters and analysts for their strengths and weaknesses, largely related to the war in Iraq and the U.S. economy, we wish to remind the candidates that we are at a defining moment for the environment. Population growth, climate change, consumption of fossil fuels, air and water pollution, and loss of biodiversity, to name a few, are not going to abate without concerted efforts, sacrifice, and political will. If either candidate wishes to fulfill his responsibility to America and the rest of the world, then he will need to make significant progress on these issues without concern for special interests, popularity, or re-election. Obama professes to be the candidate for change, and McCain says that he has wisdom bred of experience. Either way, they both need to halt the destruction of our planet and promote active environmental preservation, or they will continue to lead future generations to a precipice from which they cannot retreat.

True wilderness is a surrogate for every blade of grass, tree, or pond in a park. Wilderness medicine is medicine for the outdoors, predicated upon the notion that there will be unspoiled, unpolluted, and unencumbered forests, mountains and oceans to support our physical and emotional needs. We cannot conceive of wilderness medicine without the wilderness. The wilderness is shrinking at an alarming rate, and the most unnecessary causes are created by the activities of man. Every president since Richard Nixon has spoken to the nation about our concerning oil addiction, yet we continue to consume irreplaceable natural fuels, generate unprecedented tons of pollutants, ruin natural habitats, and endanger species. To ignore this situation or attribute it to natural cycles is dishonest, self-serving, uninformed, or ignorant.

Let us briefly review some of the environmental records and key environmental positions of these men, so that it can be clear that despite the rhetoric spun by their speechwriters, neither man should lay claim to having been a champion of the environment. At best, their past efforts have been helpful, but certainly not heroic, at a time when our world needs heroes.

Barack Obama

1. Introduced the Healthcare for Hybrids Act, which would have the federal government help cover health care costs for retired U.S. autoworkers in exchange for domestic auto companies investing at least 50 percent of the savings into production of more fuel efficient vehicles.
2. Co-sponsored the Coal to Liquid Fuel Promotion Act, supporting liquefied coal only if it emits 20 percent less carbon over its lifecycle than do conventional fuels.
3. Passed legislation with Senator Jim Talent (R-MO) to give gas stations a tax credit for installing E85 ethanol refueling pumps.
4. Worked with Senator Jim Jeffords (I-VT) to introduce the High Performance Green Buildings Act, which would increase the energy efficiency of federal buildings and schools.
5. Sponsored an amendment that became law providing $40 million for commercialization of a combined flexible fuel vehicle/hybrid car within five years.
6. Introduced legislation to enact a National Low Carbon Fuel Standard that will reduce lifecycle greenhouse gas emissions of passenger vehicle fuels sold in the U.S. by 10% in 2010 and require additional reductions of 1% annually thereafter.
7. Has opposed a summer “gas tax holiday” proposed by other candidates. However, Obama has recently proposed releasing 10% of the Strategic Petroleum reserve in order to lower oil prices. It is not clear whether or not he supports offshore drilling.
8. Calls for cutting U.S. carbon dioxide emissions 80% below 1990 levels by 2050 through a cap and trade system that would auction off 100% of emissions permits to finance development of clean energy technology; 25% of U.S. electricity to come from renewable sources by 2025; investment of $150 billion over 10 years for renewables, biofuels, and other “clean tech”; all new buildings in the U.S. to be carbon neutral by 2030; reducing U.S. oil consumption by at least 35% by 2030.
9. Advocates U.S. re-engagement with the U.N. Framework Convention on Climate Change (UNFCCC) and leadership of a new Global Energy Forum (G8 members plus five of the world’s largest emitters) to combat global climate change.

Summary: Obama states, “I believe that global warming is not just the greatest environmental challenge facing our planet – it is one of the greatest challenges of any kind. It is an issue that we ignore at our peril and at even greater peril for our children, grandchildren, and many impoverished global populations. Combating global warming will be a top priority of my presidency, and I will attend to it personally.” Obama’s words are strong, but he has not yet been in office long enough to establish a significant track record. If he is elected, we can only hope that actions will follow.

John McCain

1. Championed legislation to limit aircraft flights over the Grand Canyon.
2. Was absent for key votes on fuel efficiency, wildlife preservation, and mining.
3. Has sponsored or co-sponsored environmental protection bills related to protecting whales, improving fuel efficiency, and awarding tax credits for energy efficiency.
4. Held balanced, scientific climate hearings; has admitted the presence of anthropogenic climate change.
5. With Senator Joe Lieberman, drafted the first economy-wide cap and trade bill for carbon emissions (Climate Stewardship Act), which did not pass in 2003.
6. Re-introduced the climate bill in 2005, with added subsidies for nuclear energy; this was voted down.
7. Opposed drilling in the Arctic National Wildlife Refuge, but supports offshore oil and natural gas drilling.
8. Filibustered to oppose the 2003 energy bill, which advocated use of fossil fuels.
9. Suggested suspending the federal gasoline tax.

Summary: John McCain can best be characterized as inconsistent. He has had moments of appearing to be concerned about the environment, but these do not mesh well with his voting attendance record. He still is guided to a certain extent by partisan considerations. He appears to be somewhat enlightened in comparison to other Republicans, but is in no sense an expert on environmental issues, and has not made an extraordinary effort to surround himself with thought leaders. He has at least one strategist who understands the importance of environmental issues with voters, but McCain himself is a wild card on matters pertaining to land and conservation issues.

The League of Conservation Voters (LCV) provides objective, factual information about the most important environmental legislation and the corresponding voting records of all members of Congress. It offers a consensus of experts from more than 20 respected environmental and conservation organizations. Congressional members are graded on key votes, with 100 representing a perfect score. Obama’s lowest LCV score was 67 and highest 100 (2006), with a lifetime score (career average during years in office) of 86. McCain has scored as low as 0 (2007) and as high as 67, with a lifetime score of 24.

One of these men will be elected the next President of the United States. Because we hope that both are sufficiently intelligent and perceptive to recognize the truth and be cognizant of the urgent need for environmental remediation, we respectfully ask our next President to not only honor his campaign promises to prioritize the environment, but to consider the following bipartisan course of action:

1. Create an independent commission to gather the science and report each year to the nation the state of the global environment. Within that report, the following, at a minimum, should be addressed: global warming, depletion of stratospheric ozone, destruction of forests, polar melting, deficiencies in water production and sanitation, human population growth and dynamics, and the economic, social, and medical impacts of all of the aforementioned issues.
2. Create a National Institute for the Environment (NIE) with a budget sufficient to support epidemiology, basic science, and applied research in environmental science.
3. Create an Environmental Corps for college graduates, who will serve a paid 2 to 4-year tour of public service duty in exchange, year for year, for college education funding.
4. Pass legislation that will definitively create alternate (to fossil fuels) energy sources for the U.S. no later than a decade from now, integrating the principles of a Renewable Portfolio Standard, such that the consumption of fossil fuels can be decreased to a situation of net energy gain from all sources by the year 2018.
5. Eliminate financial support for any federal or state entity, program, or business, without exception, that does not have a neutral carbon footprint by the year 2013.
6. Codify and institute a progressive carbon cap and trade policy.
7. Remove all tax breaks from fossil fuel-consuming industries.
8. Adjust utility regulation to promote fuel efficiency.
9. Provide federal dollars to subsidize free fuel-efficient public transit.
10. Impose an average 40 mile-per-gallon minimum for all newly manufactured passenger cars driven in the U.S. by the year 2018.
11. Provide dollar for dollar tax credits to persons who retrofit or construct fuel-efficient dwellings.
12. Consider it the obligation of the U.S. to take a leadership position and collaborate with other nations to eradicate potable drinking water deficiencies worldwide by the year 2018.
13. Cease and desist on drilling for oil, mining for coal, logging for lumber, or any other environmental predatory practice in any current and future protected natural habitat, including the Arctic National Wildlife Refuge.


These are difficult mandates that will require inspirational efforts and political fortitude, and sacrifice on the part of all citizens. The President of the United States leads the greatest free nation in the world, and as such, carries more obligation than do other world leaders. If other nations are not yet willing to “step up to the plate” and do their fair share, then our country must lead by example. There will undoubtedly be inconvenience and economic reconfiguration, such that certain industries will mount mighty challenges to these proposals. We are used to that sort of thinking – after all, the tobacco industry has been killing people for years with little remorse, despite all the evidence about the health effects of tobacco. But killing millions of smokers with cigarettes does not pose irrevocable harm to mankind, only to the unfortunate victims and their families of cancer and cardiovascular disease. War and pandemics are serious matters, but in our estimation, environmental issues are of a far greater magnitude, perhaps of a permanent catastrophic nature over a relatively short period of time. We do not see a requirement to unequivocally predict the future, because preserving the planet can only be good, whether or not it is absolutely necessary at this particular moment. When we see a patient with accelerated hypertension, we control it before we are called upon to treat that same patient’s heart attack or stroke. A climber who has a headache and cannot walk a straight line is brought to a lower altitude before his brain swells further and he cannot be saved. We call upon our next President to assemble the very best clinicians to treat our planetary patient, before every nation is forced to be put on life support.

Paul S. Auerbach, MD, MS, FACEP, FAWM
Luanne Freer, MD, FACEP, FAWM


Tags: Barack Obama, John McCain, energy, environment, Obama, McCain, wilderness medicine, outdoor medicine, healthline

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Thank You to "six until me" for Grand Rounds

Thank you to Kerri Morrone Sparling at "six until me" for including my post about foot blisters in this week's edition of Grand Rounds. Grand Rounds is a weekly compilation of posts related to health care compiled by a host, who makes a great effort to compile an interesting collection for readers. Ms. Sparling's work is delightful, and it was a pleasure to contribute to her blog.

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Chantix Precaution and the Outdoors

The Institute for Safe Medication Practices recently released the following report, abbreviated and annotated by me for the purpose of this post, originally written by Thomas J. Moore (Senior Scientist, Drug Safety and Policy, ISMP), Michael R. Cohen RPh, MS, ScD (President, ISMP) and Curt D. Furberg, MD, PhD (Professor of Public Health Sciences, Wake Forest University School of Medicine).

Strong Safety Signal Seen for New Varenicline Risks

Executive Summary

A strong signal of multiple safety problems with Chantix (varenicline), a drug to help people stop smoking, has been seen in a pilot program to identify new drug risks in adverse drug events reported to the U.S. Food and Drug Administration.

Varenicline is suspected in various adverse drug event reports of causing a wide spectrum of injuries, including serious accidents and falls, potentially lethal cardiac rhythm disturbances, acute myocardial infarction, seizures, psychosis, aggression and suicide. The cases were analyzed and classified using computerized excerpts of adverse event reports that the FDA publishes for research use.

The FDA approved varenicline in May 2006 after granting it a priority review. Varenicline is a partial agonist of one of the nicotinic acetylcholine receptors in the brain and nervous system, and currently the only marketed and approved drug with this mechanism of action. It is prescribed for the purpose of (tobacco) smoking cessation.

In the 4th quarter of 2007, varenicline accounted for 988 serious injuries in the U.S. reported to the FDA. This large volume of reports prompted us to conduct an analysis of all adverse events for varenicline since marketing approval in 2006.

The FDA has recently issued a Public Health Advisory about one of the most marked adverse effects of varenicline, psychiatric symptoms, that included “changes in behavior, agitation, suicidal ideation, attempted and completed suicide.” However, the FDA alert provided no information about the numbers of reported neuropsychiatric events among treated smokers.

The adverse drug event reports for varenicline describe other kinds of serious harm for which no warnings now exist, either from the FDA or from the manufacturer, Pfizer Inc. The cases (including those with psychiatric effects) were classified using standardized medical queries developed by the pharmaceutical industry to identify potential adverse events in clinical studies and postmarket surveillance. Adverse event reports in themselves do not establish a causal link to the drug, only that an observer suspected a relationship. Depending on the features of the specific event, it could be counted in multiple categories, and classifications are not definitive. Among the most prominent were:

· Accidents and injuries. A total of 173 serious events described accidental injury, including 28 road traffic accidents and 77 falls, some leading to fractures of rib, facial bones, hand, ankle, spine, and lower limbs. In these cases a variety of potential causes were identified, including loss of consciousness, mental confusion, dizziness and muscle spasms.

· Vision disturbance. At least 148 reports contained medical terms indicating vision disturbances, including 68 cases described as blurred vision and 26 terms indicating transient or other forms of blindness. This reported effect could also describe a mechanism that could or did contribute to accidents and injuries.

· Heart rhythm disturbances. The FDA received 224 domestic reports classified as potential cardiac rhythm disturbances. This category, however, was dominated by reports of sudden loss of consciousness, an event that could also have non-cardiac causes. However, this category also included smaller numbers of cardiac arrests and identifiable abnormal cardiac rhythms

· Seizures and abnormal muscle spasms or movements. Serious reported events included 86 cases of convulsions (seizures), 372 reports of a wide variety of movement disorders, including tremors, muscle spasms, twitching, tics, drooling, and motor hyperactivity. The extent to which these problems resolved with a reduced dose or by halting treatment could not be determined from these data.

· Moderate and severe skin reactions. Reported serious events included 338 cases of hives or swelling of the tongue, face, eyes, lips or other areas.

· Diabetes. The FDA has received 544 reports suggesting varenicline may be related to a loss of glycemic (sugar) control. This category included many cases of weight loss or gain that could have alternative causes, but also identified numerous cases of symptoms and laboratory tests consistent with new onset diabetes.

Recommendations (per the report)

We have immediate safety concerns about the use of varenicline among persons operating aircraft, trains, buses and other vehicles, or in other settings where a lapse in alertness or motor control could lead to massive, serious injury. Other examples include persons operating nuclear power reactors, high-rise construction cranes or life-sustaining medical devices. Based on reports of sudden loss of consciousness, seizures, muscle spasms, vision disturbances, hallucinations, paranoia and psychosis, we believe varenicline may not be safe to use in these settings.

In addition, we recommend that patients and doctors exercise caution in the use of varenicline and consider the use of alternative approaches to smoking cessation.

Finally, we urge the FDA and the manufacturer to provide warnings to doctors and patients for those adverse effects that can be adequately documented through existing data, and to undertake on a priority basis epidemiological studies or other research to assess other potential risks."

MY COMMMENTS

Since the report paraphrased above was issued, the Federal Aviation Administration has banned the use of Chantix for pilots and air traffic controllers. Based on the information presented within this report, it seems prudent to avoid using Chantix if a person will encounter a potentially dangerous outdoor situation, in which one of the side effects might be expected to contribute to an accident. What was not presented in the report is any information about how soon adverse effects appear after Chantix is started. In other words, is a patient likely to expect side effects in the first week or month of using the medication? Are the side effects predictable or unpredictable? To what extent is there any interaction with pre-existing conditions, physiological state, interaction with other medications, diet, etc.?

Smoking cessation is extremely important, probably one of the top five most beneficial health activities that can be undertaken by anyone. As utilization data about the effects and side effects of Chantix are accumulated, we all hope that the benefits of using Chantix outweigh the risks. Until such time as we can determine the nature and true risk(s) of using this medication, it is prudent to recommend that it not be prescribed to persons who will be in any situation in which one of the above reported side effects, in particular alertness and motor control, would put the patient in peril.

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Foot Blisters 1

The Wilderness Medical Society Annual Meeting & 25th Anniversary held in Snowmass, Colorado from July 25-30, 2008 was fantastic in every aspect. The meeting was attending by more than 300 individuals, and included lectures, workshops, evening presentations and a celebration banquet complete with costume ball. I can’t imagine how the meeting might have been better, unless each and every one of you could have been in attendance.

In an extended series of posts, I am going to feature information adapted from the meeting presentations and syllabus, graciously contributed by speakers, all of whom are WMS members. They are all to be commended by the innumerable volunteer hours they contribute to wilderness medicine education, making the outdoors safer and a more enjoyable experience for all of us.

The first two posts from the meeting are about one aspect of backcountry foot care – blisters - based upon information provided by Dr. Grant S. Lipman, who is a Clinical Assistant Professor of Surgery in the Division of Emergency Medicine at Stanford University.

The cause of a friction blister is the repeated action of skin rubbing against another surface. As the external contact, such as a coarse, sweat- and dust-impregnated sock, moves across the skin, the opposing force is called the frictional force (Ff). The combination of the magnitude of the Ff and the frequency of the rubbing of the object across the skin determines the probability of a blister development. Therefore, the greater the Ff, the lower the number of rubbing cycles needed for blister development.

The outermost layer of the skin is known as the epidermis. The epidermal skin layers are, from superficial to deep, called the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. In terms of foot blister formation, shear forces extend horizontally between skin layers, between the skin and sock interface, between socks, and between socks and footwear. When the forces within a shoe or boot overcome resistance, sliding occurs. Repeated sliding at a friction point causes an initial sensation of heat – the so-called “hot spot.” Further friction on a hot spot causes blister formation. Skin cells in the stratum spinosum tear and separate. The superficial cells of the overlying layers remain relatively intact, forming a blister’s “roof.” The underlying skin layer, and associated interface between the epidermis and dermis, are usually unaffected. The separated space in the area under the blister roof quickly fills with fluid.

Thick skin like that found on the palms and soles is more likely to undergo blister formation. The epidermis in these areas is usually thick, tightly adhered to underlying structures, and relatively immobile, which causes greater friction than that induced in thinner, more supple skin, such as that found on the back of the forearm.

Blister healing is rapid if one can reduce further friction and worsening of the injury. In a mere 24 hours after blister formation, there is regenerative growth in the blister wound, and at 48 hours, evidence of healing in the basal layer. However, in the presence of continued friction and pressure, as is often the case in the backcountry, the body benefits from medical attention that provides healing assistance.

As in all of medicine, prevention is paramount. To prevent blisters, one must minimize friction generated by the normal biomechanical forces of walking and the contributors to friction. The force between the foot and the insole is determined by the weight of hiker as well as any weight being carried. Reducing the magnitude of the forces on the feet can be as simple as reducing the carried load, whether that means losing personal weight or shedding pounds from the backpack. Another way to minimize the force on the feet is to use a padded insole or arch support. This does not technically reduce the force, but it helps to evenly distribute pressure over the bottom surface of the foot, which thereby decreases the tendency for blister formation.

Either increasing or decreasing the ease with which two surfaces rub against each other can reduce frictional forces. If there is easy sliding, then coefficient of friction is small, reducing the chances for blister formation. At the opposite extreme, if there is no rubbing, then there is no movement at the skin-surface interface.

Shoes or boots should fit properly and comfortably. Shoes that are too tight can increase contact points of pressure on the foot. Those that are too loose can allow excess movement that allows generation of friction. Overly narrow shoes typically cause blisters on the large and small toes. Loose shoes can create blisters on the tips of toes from sliding and jamming the tips into the toe box. A toe box that is too shallow can cause blisters on the tops of the toes from repeated contact.

In general it is best to fit (size) shoes in the evening, because feet tend to swell throughout the day. When trying on shoes or boots, make sure to wear the same socks and/or insoles or orthotics that you will be using on the trails. Size boots to compensate for thicker socks. Allow for ample time to break in new footwear. This will stretch the material, sometimes loosen it and increase flexibility, and thereby reduce friction points against the foot. The breaking-in period also conditions the skin itself by causing epidermal thickening.

Soft and supple feet are better able to withstand frictional stress than are cracked and horny feet. Many podiatrists recommend preparing feet with Bag balm, a moisturizer, petrolatum, or other softening agent. Calluses should be filed down to prevent them from tearing off or contributing to the development of deep blisters underneath that are extremely painful and difficult to drain. Toe nails should be kept trimmed short and beveled downwards to reduce the development of bleeding underneath the nails (subungal hematomas).

It is possible to reduce shear forces in the footwear system by deliberately creating a weak shear layer using two pairs of socks. The goal is to have friction occur between the two layers of socks, not between the skin and the socks. A smooth, thin, snug fitting synthetic sock worn as an inner layer against the foot will move with the foot, while a thick, woven sock worn as an outer layer tends to move with the footwear and cushion against shocks. The thinner synthetic liner sock will also assist in moisture control by wicking moisture and perspiration away from the skin surface.

A preventive barrier between the footwear and a potential point of blister formation can save many an outing. Barriers are best utilized as preventive measures before blisters form, either at the beginning of the day or as soon as a hot spot develops. The barrier needs to be adhesive so it can remain fixed to skin, despite the action of friction, warmth and/or moisture. Micropore paper tape, cloth tape, Elastikon elastic tape, moleskin, Spenco Blister Pads, Blist-O-Ban, and duct tape are methods to prevent blister development. Using an adhesive such as tincture of benzoin or Pedi-Pre Tape Spray will help keep the barrier adherent to the skin.

A cardinal rule of taping is to smooth out any wrinkles, and cut off “dog ears” that may lead to further pressure points. ENGO Blister Prevention Patches are slick fabric-film composite patches that are placed on the inside of the shoe or insole. Silicon gel toecaps and sheaths reduce friction between the toes and therefore blister formation in this common and frustrating location to.

Keep the skin clean and dry to minimize friction. Skin hydration leads to increasing contact area and friction, so moist skin results in more frequent blisters. However very wet skin has a low incidence of blister formation, likely due to the lubricating effects of water on the skin surface.

High-technology oversocks combine waterproof materials with traditional socks to help keep feet dry when repeatedly exposed to water. Combining GORE-TEX oversocks with wicking liner socks and foot antiperspirant is a method to reduce foot moisture. Consider the addition of gaiters to help eliminate dirt, gravel, sand, and rocks from entering the sock-shoe system. If your feet are often moist or sweaty, then try to change socks frequently.

Drying powders decrease moisture for short periods of time and are useful in the evening to dry out feet, but after about one hour may actually increase the friction between surfaces. Lubricants have been developed that are more advanced than traditional Vaseline, which is greasy and tends to trap grit particles, which are irritating and may increase friction and blister production. Advanced lubricants that combine silicone and petrolatum have a silky feel, prevent friction, and repel moisture from the skin. Lubricants can be applied preemptively, or over tape when hot spots develop. However, after about 3 hours, friction is increased as the lubricants are absorbed into the skin and socks. Lubricants should be tested before use on the trail to assess for allergic reaction, and if used, reapplied frequently.

Antiperspirants irritate and block sweat ducts, reducing the amount of perspiration. People who suffer from a condition called hyperhidrosis experience excessive foot perspiration and subsequently have extremely moist feet. These people may benefit the most from antiperspirants.

The next post in this series will be about blister treatment.

Tags: blister, foot care, feet, wilderness medicine, outdoor medicine, healthline

Labels: blisters, feet, foot care, Lipman

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Hiking Week at Canyon Ranch in Tucson

I've been invited to participate in Canyon Ranch in Tucson’s Hiking Week, November 1-8, 2008, for six consecutive days of group hikes and camaraderie with fellow outdoor enthusiasts. I've never before been to Canyon Ranch, so I'm really looking forward to it. The week will include treks into rugged canyons and also to alpine terrain, and will be a great opportunity to witness some beautiful scenery, meet new people, and enjoy the great outdoors.

The event is advertised to challenge the body and delight the spirit. We'll take daily guided journeys amid the exotic landscape of the Sonoran Desert and the cool pine forests of nearby mountaintops. Participants should be advanced hikers, capable of trekking 10 to 15 miles daily with elevation gains of up to 5,000 feet. Hikes take place at altitudes between 2,500 and 9,500 feet, and start early each morning, concluding by mid- to late afternoon. We'll also learn some wilderness medicine along the way.

Canyon Ranch, the world’s most celebrated health resort, is dedicated to the pursuit of optimal health – feeling your absolute best physically, mentally and spiritually. There are opportunities for dozens of daily fitness classes and outdoor activities, delicious spa cuisine, myriad wellness consultations, plus a tempting menu of rejuvenating body and skin care treatments. This abundance of choice, plus warm, attentive service and an atmosphere of casual luxury, has made award-winning Canyon Ranch a favorite of savvy spa-goers for nearly 30 years.

For all the obvious reasons, it will be wonderful to spend this terrific week at Canyon Ranch. I hope that some of you will be able to join me.

Tags: hiking, Canyon Ranch, wilderness medicine, outdoor medicine, healthline

Labels: Canyon Ranch, hiking

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Endurance Sunblock and Lip Protection

At the 25th Anniversary & Annual Meeting of the Wilderness Medical Society held in Snowmass, Colorado July 25-30, 2008 there were exhibitors demonstrating new products and concepts to the attendees. One of these was Outside Labs of California, representing K2 Suncare. The specific products being demonstrated were “endurance sunblock” and “endurance lip balm.” I field tested a 4 mL (15 fluid ounce) container of 50 SPF (sun protection factor) UVA (ultraviolet A) + UVB sunblock, and a 0.15 ounce (4.25 g) stick of lip balm (protectant + moisturizer) with UVA + UVB protection rated at 30 SPF.

For the sunblock, the company advertises 4 prescription grade sunscreens containing polymers that bind to the skin in such a manner to create water- and sweat-proofing. In addition, the ingredients include antioxidants and non-greasy moisturizers. I applied the sunscreen prior to hiking in the Maroon Bells near Aspen in a warm and dry environment. I sweated profusely, and am pleased to report that the sunblock didn’t appear to smear or obviously wash off. I was caught in a downpour during the second half of my hike, and the sunscreen seemed to hold well. The sun broke through after the brief storm, and I basked in the intense warmth for about an hour in order to dry out my clothing. As a reward for having properly applied sunscreen, I was spared any evidence of a sunburn.

The K2 Endurance Lip Balm was terrific. It’s packaged in an innovative cylindrical container that extrudes the solid product stick for application to your lips when you rotate the bottom of the cylinder, which allows for one-handed use. The upshot of the design, besides being cool in appearance, is that there is no cap to lose. The balm has a faint, pleasant lemony taste. It resided in my black daypack, which grew quite warm, and didn’t lose its consistency (e.g., melt).

I can highly recommend both products, which are welcome additions to the pantheon of sunblocks and lip balms.

Tags: sunscreen, lip balm, endurance, wilderness medicine, outdoor medicine, healthline

Labels: K2 Endurance Lip Balm, lip balm, Outside Labs, sunblock

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Thank You to Medical Humanities Blog for Grand Rounds

Thank you to Medical Humanities Blog for including my post about creating a defensible space against a wildfire in this week's edition of Grand Rounds. Grand Rounds is a weekly compilation of posts related to health care compiled by a host, who makes a great effort to compile an interesting collection for readers.

Labels: Grand Rounds, Medical Humanities Blog

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Acetylsalicylic Acid (Aspirin) Analog versus Acetazolamide for Acute Mountain Sickness

In Volume 9, Number 1 (2008) of the journal High Altitude Medicine & Biology, published by the International Society for Mountain Medicine, Bengt Kayser, Ronald Hulsebosch, and Frank Bosch report a randomized controlled study of the acetylsalicylic acid (aspirin) analog, calcium carbasalate, compared with a placebo and acetazolamide (Diamox) during a rapid ascent of Mount Kilimanjaro (5896 meters or 19,344 feet). The dose of calcium carbasalate used was 380 mg per day; the dose of acetazolamide was 500 mg per day. Ascent of Mt. Kilimanjaro is typical of a rapid ascent that does not require technical mountaineering skills, and is undertaken by numerous persons who are neither experienced in high altitude travel nor particularly knowledgeable about high altitude illness.

The results showed that calcium carbasalate did not prevent acute mountain sickness (AMS) or headache. A very interesting finding was that more than half the individuals taking acetazolamide developed AMS. This may indicate that the dose taken is not sufficient in general, or perhaps only that the ascent rate was too fast for this (or any) dose of acetazolamide to be effective in prevention of AMS. This is even more intriguing, and deserves further investigation, because the trend in recent clinical recommendations has been to use lower doses (e.g., 250 mg per day) of acetazolamide for the purpose of high altitude acclimatization, in order to achieve a beneficial effect while minimizing the side effects. So, it is very important to understand which circumstances of ascent call for a higher dosing regimen.

AMS is a very debilitating disorder, and is likely the harbinger of high altitude cerebral edema (brain swelling). At the very least, it causes headache, poor appetite, fatigue, nausea, and soft tissue swelling, and is markedly disruptive for adventures and recreation at high altitude. This particular study supports our current understanding that non-steroidal antiinflammatory drugs and common analgesics, such as aspirin, ibuprofen, and acetaminophen, are not useful to prevent AMS, and may only serve to mask an important symptom (headache) that indicates when a person is entering a dangerous physiological situation. Of course, if the patient and observers are confident that the headache is mild and that AMS is not progressing, it is reasonable to treat the headache with an analgesic.

photo courtesy of www.7summits.com

Tags: acetazolamide, acute mountain sickness, AMS, wilderness medicine, outdoor medicine, healthline

Labels: acetazolamide, acute mountain sickness, AMS, calcium carbasalate, high altitude, high altitude medicine

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Brain Cooling for Brain Injury

Research suggests hypothermia therapy may not benefit children with brain injuries. In June, Reuters reported that "chilling the body to well below its normal temperature does little to protect children from further damage after an accidental brain injury, and may even make things worse," according to a study published in the June 5 issue of the New England Journal of Medicine. The original article is "Hypothermia Therapy after Traumatic Brain Injury in Children" by James S. Hutchison, M.D. and his colleagues for the Hypothermia Pediatric Head Injury Trial Investigators and the Canadian Critical Care Trials Group (N Engl J Med 2008;358:2447-56).

This was a multicenter, international trial in which researchers enrolled 225 children (mean age of 10) who were admitted with acute brain injury to pediatric intensive care units in 17 centers. The investigators randomized 108 children to hypothermia therapy -- cooling to about 32.5° C -- initiated within eight hours of the injury and maintained for 24 hours and 117 children to normothermia -- about 37° C. The researchers found that at six months post-injury, 31 percent of children given hypothermia therapy had a severe disability, were in a persistent vegetative state, or had died, compared with 22 percent of patients who were not cooled. Although a greater proportion (21 percent) of patients died in the hypothermia group than in the control group (12 percent), the difference fell short of statistical significance. The conclusions noted in the original article were that "in children with severe traumatic brain injury, hypothermia therapy that is initiated within 8 hours after injury and continued for 24 hours does not improve the neurologic outcome and may increase mortality."

This is a bit of a surprising finding, in part because animal (rodent) studies have been encouraging. However, as we have learned from many other therapeutic issues (e.g., cancer therapy), the translation from animal models to humans is not always guaranteed, which is why clinical investigations are performed in humans. The underlying premise of using hypothermia for acute brain injury is that by cooling the brain, its metabolic rate will slow and therefore it will tolerate an episode of low oxygen, low blood flow (perhaps due to brain swelling), and the provision of diminished energy resources (also perhaps due to brain swelling).

Can these results be extrapolated to other situations that involve the brain for which controlled hypothermia is sometimes recommended, such as a drowning episode, or for which it is not currently recommended, such as high altitude cerebral edema? We do not know.

The current dictum for victims of accidental hypothermia is that their brains may be protected by the low temperature, so that a resuscitation may be carried out differently (e.g., fewer chest compressions and rescue breaths per minute) than would be a resuscitation under a condition of normal body temperature. This has never been precisely studied, but is a generally accepted notion. Whether or not this study of traumatized brains in children might cast doubt upon that notion remains to be seen, because in hypothermia victims who survive neurologically intact, there is no underlying structural brain injury.

image courtesy of www.medicineworld.org

Tags: hypothermia, brain injury, traumatic brain injury, wilderness medicine, outdoor medicine, healthline

Labels: brain injury, children, hypothermia, trauma

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Kershaw Carabiner Tool

I really like to "demo" innovative new outdoor products with medical or survival applications. Simplicity is sometimes elegant. This is the case with the new Kershaw Carabiner Tool, Model 1004. This five-in-one tool features a partially serrated "shaving-sharp" (it works - I tried it) blade, flat-head screwdriver, Phillips-head screwdriver, and bottle opener packaged in a carabiner-style handle. The handle is not load bearing, but can be attached easily to anything with a D-ring or loop, such as a belt or backpack. It opens and closes with a spring-loaded locking gate that is secured shut with a screw-on closure. The tool comes in blue, red, silver or black. The handle is aluminum coated with Teflon. The blade is stainless steel with a Rockwell hardness rating of 57-58 that locks into a stainless steel liner. As is the case with many Kershaw knife blades, the proximal portion is serrated for tough cutting jobs like rope or small branches, while the distal part is a straight blade. The retail price is $59.95 U.S.

Kershaw knives are manufactured by KAI Corporation. They are extremely high quality and range from camp axes to sportsman's shears to blades for hunters and fishermen, to knives for scuba divers, to special bladed tools for climbers and tactical operations. Cutting instruments are essential for outdoor medicine, whether it be to trim a wound or carve wood for a splint. Kershaw sets an example for other knife manufacturers for the quality and performance of their blades.

Tags: carabiner tool, Kershaw, knife, wilderness medicine, outdoor medicine, healthline

Labels: blade, carabiner, carabiner tool, Kershaw, knife

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