Sawyer Water Filter

Wilderness and outdoor activities take many of us to the farthest reaches of the globe. Adventures in the mountains, forests, oceans and deserts bring us to countries in Africa, South America, Central America, Asia, and other places, where food, water, and shelter are in scarce, if any, supply. People living in the most impoverished regions are not familiar with bottled water and toilet paper; some barely have concepts of floors and roofs. Water and waste go arm in arm in the struggle against famine, drought, starvation and disease. Of all of these, the situation that seems most amenable to remediation seems to be water, yet large scale solutions elude us or are not implemented for lack of interest, organization, finances, or political will.

Public health experts worldwide agree that one of the most pressing needs of humanity is to assure an adequate potable water supply. The current state of affairs is worst in developing countries, and accounts for hundreds of millions of cases of infectious diarrhea, resulting in millions of deaths each year. In the future, water shortages, both for drinking and for irrigation, may force migration of hundreds of millions of individuals over the course of a few decades. According to the United Nations, more than 5 billion persons on Earth may live under severe water stress by the year 2025. Currently, at least 1.1 billion persons lack adequate safe drinking water worldwide, 2.6 billion lack adequate sanitation, and nearly two million children under the age of five years die each year because of one or both of these deficiencies. This condition cannot be allowed to persist, or we will continue to witness similar, or worse, human deprivation and devastation. Furthermore, struggles over water will inevitably lead to crime and armed conflict.

Clean water is essential, to drink and to wash hands. There are no doubt many solutions for water purification and disinfection of which I am not aware, but one has been brought to my attention recently that merits evaluation for the possibility that its implementation might be a godsend to persons who have access only to impure water, commonly distributed by water vendors. The method is the Sawyer Point One Filter Bucket Adapter Kit, which includes a 0.1 micron absolute hollow fiber membrane filter, adapter, and hose; a filter cleaner; a hole cutter (sturdy drill bit; a drill is not necessary for a thin-walled bucket), and filter hanger instructions.

The filter is rated to remove bacteria, spores, and cysts, such as those that cause cholera, botulism, typhoid, amoebic dysentery, traveler's diarrhea, salmonellosis, shigellosis, streptococcal infections, giardiasis, cryptosporidiosis, and cyclosporiasis. According to Sawyer, more than 2,000 gallons of water per day may be passed through a single filter by gravity methods alone.

This is abstracted from the product literature: "The Sawyer Point One Filter uses medical technology developed from kidney dialysis. The filter exceeds all U.S. EPA recommendations for drinking water. Follow the directions for use and attach (the filter) to any plastic bucket or pail to yield clean water in remote locations. This biological filter does not require the use of chemicals. It cleans 5 gallons of water in under 20 minutes. The filter is cleaned by back washing it with clean water. This filter cleaning process is not required often unless one is filtering very turbid water. No replacement filters or cartridges are necessary."

For more information and to view an instructional video, visit www.SawyerPointOne.com.

In addition to this filter, Sawyer also distributes a .02 Micron Purifier, which is also available in a bucket adapter kit. This is advertised to be the first portable filtration device to physically remove viruses in addition to bacteria, which it does at a >5.5 log (99.9997%) rate. This obviously provides an even greater degree of protection against infectious agents of disease.

I have assembled the Point One Filter system, and it operates smoothly and as advertised. The potential for this system, and in particular these filters, to improve human health is enormous. With minimal instruction and maintenance requirements, the filters can be deployed in areas where other methods of disinfection are impractical or cost prohibitive. These are powerful products. I intend to carry one or more Point One or Point Zero Two bucket adapter kits with me to any location in which I am concerned about the purity of the water, and will leave them behind so that others may benefit.

Preview the 17th Annual WMS Winter Meeting, "Wilderness & Mountain Medicine," which will be held at The Canyons in Park City, Utah, February 20-25, 2009.

Tags: water disinfection, water filter, Sawyer Products, wilderness medicine, outdoor medicine, healthline

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WMS Winter Meeting - Wilderness & Mountain Medicine

Happy Thanksgiving! I can think of no better way to start off Turkey Day than by letting you know the details about a terrific continuing medical education (CME) meeting that will be held in February. The Wilderness Medical Society is excited to announce its 17th Annual Winter Meeting, entitled "Wilderness & Mountain Medicine."

The meeting will be held February 20-25, 2009 at The Canyons, a beautiful ski resort location in Park City, Utah. The Canyons is Utah's largest ski and snowboard resort, and is the recipient of legendary Utah powder.

The program, which is accredited for a maximum of 24.75 hours of credits towards Fellowship in the Academy of Wilderness Medicine and approved for a maximum of 22/25 AMA PRA Category 1 credits, is another assembly of experts who will deliver state of the art education and entertaining evening programs, such as "STEEP - Big Mountains and Extreme Skiing," "Everest ER - Medicine, Climbing and Guiding in the Himalaya," and "Passion and Compassion - Climbing and Medicine: One Man's Story." As is customary for the WMS, there will be plentiful workshops, and the entire conference is fronted by preconferences and optional workshops, including Advanced Wilderness Life Support (AWLS), a Level 1 Avalanche Course, and an Introduction to Backcountry Touring.

Please join me and a stellar distinguished faculty for what promises to be an exciting and memorable educational experience. See you in Park City!

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Inhalers and the Environment

With the enduring premise that there will not be wilderness medicine with the wilderness, it is gratifying to note that it has been approximately 6 months now since the Food and Drug Administration (FDA) advised patients to switch to hydrofluoroalkane (HFA)-propelled albuterol inhalers. Chlorofluorocarbon (CFC)-propelled inhalers, which release chemicals harmful to the environment, will be prohibited for sale in the U.S. after December 31, 2008.

The specific problem with the CFC-propelled inhalers is that they are felt to contribute to depletion of the stratospheric ozone layer, which would increase the potential for harmful ultraviolet radiation to reach the earth's surface. Among other problems, this might lead to increases in skin cancer and cataracts, and might contribute to global warming.

The phaseout of CFC-propelled inhalers is the result of the Clean Air Act and an international environmental treaty, the Montreal Protocol on Substances that Deplete the Ozone Layer. Under this treaty, the U.S. agreed to phase out production and importation of ozone depleting substances, including CFCs.

There are three HFA-propelled albuterol inhalers that have been approved by the FDA: Proair HFA Inhalation Aerosol (Ivax), Proventil HFA Inhalation Aerosol (Schering-Plough), and Ventolin HFA Inhalation Aerosol (GlaxoSmithKline). There is an HFA-propelled inhaler containing levalbuterol, a medicine similar to albuterol, available as Xopenex HFA Inhalation Aerosol (Sepracor).

Albuterol inhalers are often the mainstay of therapy used to treat bronchospasm (airway swelling and constriction that causes wheezing) in persons with asthma and chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema. Patients use albuterol inhalers to deliver medicine directly into the lungs, which is usually a much more effective method of drug delivery in these situations than is oral administration.

HFA-propelled albuterol inhalers may taste and feel different than the CFC-propelled albuterol inhalers. The spray of an HFA-propelled albuterol inhaler may feel softer (less forceful) than that of a CFC-propelled albuterol inhaler. Patients must also be certain to prime and clean HFA-propelled albuterol inhalers. Doing so prevents buildup of the drug in the inhalation device, which could block the medicine from reaching the lungs. Each HFA-propelled albuterol inhaler has different priming, cleaning, and drying instructions, so patients are wise to read and understand the instructions for their particular device before first using the inhaler.

The CFCs released from albuterol inhalers into the atmosphere represent a "drop in the bucket." According to an article that appears at the conservation oriented website "Mother Earth News," air conditioners and other cooling devices account for the majority of CFC release into the atmosphere. The article reviews where CFCs are used around the home and business and describes some of the alternatives currently available or under development. We clearly have a long way to go, but at least the FDA and pharmaceutical industry have taken a step in the right direction.

Preview the 17th Annual WMS Winter Meeting, "Wilderness & Mountain Medicine," which will be held at The Canyons in Park City, Utah, February 20-25, 2009.

Tags: albuterol, albuterol inhaler, ozone layer, wilderness medicine, outdoor medicine, healthline

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Thank You to Canadian Medicine for Grand Rounds

Thank you to Canadian Medicine for including my post about acute mountain sickness and high altitude cerebral edema in this past 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 present them in an informative and entertaining manner.

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Consumption of Nuts, Corn and Popcorn Not Associated with Diverticular Disease

Backpackers and other outdoor travelers sometimes subsist on less-than-ideal diets, including "junk food," and items that are easy to carry because of their packaging. Some favorite foods include nuts (along or contained in "GORP"), corn nuts, and popcorn. Nuts are actually quite nutritious, containing excellent protein, fiber, vitamins, minerals, and other micronutrients.

Diverticular disease (diverticulosis) can convert to diverticulitis and/or diverticular bleeding. Here is a bit of information on diverticulitis:

Diverticula are small outpouchings that develop at weak points along the wall of the colon (large bowel), probably because of high pressures associated with muscle contractions during the passage of stool. When these sacs become obstructed and/or inflamed (most frequently in middle-aged or elderly individuals), they enlarge and create pain and fever, known as diverticulitis. Usually, the left lower quadrant is involved, because diverticula tend to form in the left-side portion of the colon (descending colon) more frequently than in the right-side portion (ascending colon) or horizontal connecting section (transverse colon). A ruptured diverticulum can cause a clinical picture much like that of a ruptured appendix, with pain in the left side of the abdomen instead of the right side. The victim should seek medical attention, and his diet be limited to clear fluids. Antibiotics (metronidazole combined with doxycycline, amoxicillin-clavulanate, trimethoprim-sulfamethoxazole, metronidazole, cefixime, ciprofloxacin, or cefpodoxime) should be administered if help is more than 24 hours away.

As pointed out in an article in the August 17, 2008 issue of the Journal of the American Medical Association, entitled "Nut, Corn, and Popcorn Consumption and the Incidence of Diverticular Disease," by Lisa Strate, M.D. and colleagues, doctors have historically advised persons with known diverticular disease (e.g., the presence of diverticuli) to avoid eating nuts, seeds, popcorn, corn, and other high-residue foods. This is on the presumption that as these food products pass through the bowel partially or completely nondigested, they may either cause trauma to the diverticuli or lodge in them, causing them to become obstructed and inflamed. This recommendation has been around for as long as I have been practicing medicine, and has always been presumed to be true, reinforced by anecdotes. I've been as guilty as the next person in this regard, citing for evidence a patient that I remember who had a watermelon seed pop out of an abscess in his flank, presumably the result of retention within a diverticulum, obstruction, diverticulitis and abscess formation, and erosion to the skin surface.

In the study reported by Dr. Strate, 47,228 men aged 40 to 75 years without known diverticulosis or diverticulitis completed a self-administered questionnaire about medical and dietary information. If any of the men reported newly diagnosed diverticulosis or diverticulitis, they were asked to complete a supplemental questionnaire. During 18 years of follow-up, there were 801 cases of diverticulitis and 383 cases of diverticular bleeding identified. There was no association seen (e.g., no increased risk) for those who ate nuts, popcorn, or corn with new-onset diverticulitis or diverticular bleeding.

This was a good study, and the discussion took into account any behavioral changes, gender, and age. It appears from this evaluation that one may eat a "backpacker's diet" without fear of inducing diverticulitis. However, if you don't eat and drink properly, you may still encounter infectious diarrhea, constipation, or other sequelae to dietary indiscretion.

image courtesy of www.thenutfactory.com

Preview the 17th Annual WMS Winter Meeting, "Wilderness & Mountain Medicine," which will be held at The Canyons in Park City, Utah, February 20-25, 2009.

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Update on AMS and HACE

This is the seventh 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. This post relates expert advice about acute mountain sickness (AMS) and high altitude cerebral edema (HACE) from Dr. Peter H. Hackett, MD, FACEP, who is Director of Emergency Services at Telluride Medical Center and Director of The Institute for Altitude Medicine in Telluride, Colorado.

The incidence of acute mountain sickness (AMS) varies with location, depending on both absolute altitude reached and rate of ascent to altitude. It has been estimated that 15 to 40% of Colorado resort skiers (depending on the altitude of the resort) develop AMS, and studies have shown an incidence of 40% in Mt. McKinley climbers and 70% in Mt. Rainier climbers. Given the huge numbers of Colorado tourists (10 million a year), this is not a trivial problem. High altitude cerebral edema (HACE), or brain swelling, is defined as the progression of cerebral symptoms and findings of ataxia (difficulty with balance, walking, and muscular coordination) and change in consciousness.

The sleeping altitude is the critical factor, with 9,000 feet being a significant threshold for illness (>20% incidence), and 8,000 to 9,000 feet less of a problem (perhaps 10 to 15% incidence), while below 8,000 feet, AMS is uncommon (but still possible). Susceptibility to AMS is not related to physical fitness or gender, although women less frequently suffer from pulmonary edema (fluid in the lungs). Older adults may be less susceptible, while limited data suggest that children probably have the same incidence as does the general adult population.

Individual susceptibility and reproducibility are well documented. Contributing factors include low lung capacity, a less vigorous breathing response to conditions of low oxygen content in the blood, and exaggerated pulmonary hypertension (high pressures in the circulation of the lungs) in response to hypoxia (for high altitude pulmonary edema, or HAPE). Brain circulatory responses and dynamics play an important role, but are difficult to test at sea-level.

Currently, past history of AMS is the most significant risk factor and best predictor. Early diagnosis is the key to successful management and a high index of suspicion is critical. The setting is rapid ascent to a higher altitude in unacclimatized persons. The symptoms include headache, poor or no appetite, dizziness, nausea, insomnia, feeling tired, fatigue, and shortness of breath. Difficulty with (erratic) breathing is common during sleep, but not a sign of AMS. Early AMS feels exactly like a hangover. In the early stages, physical findings may be lacking. When advanced, the findings are those of fluid in the lungs and brain swelling. Ataxia, change in mental status and bluish skin discoloration (particularly noted in the fingers and toes and around the lips, also known as cyanosis) are the most useful indicators of serious illness.

The differential diagnosis of AMS includes dehydration, exhaustion, carbon monoxide poisoning (this is very important indoors, or in a tent or igloo), infections of lung or brain, viral syndromes, migraine events, transient ischemic attack (TIA, of the brain), hypothermia, drugs, and psychiatric problems.

The pathophysiology of moderate to severe AMS and HACE is clearly related to brain swelling. Whether early AMS, especially the headache, is due to brain swelling is not yet established. Factors contributing to brain swelling include, but are not limited to, the degree and rate of onset of hypoxemia (low oxygen content in the blood), inadequate breathing (known as hypoventilation, which can be due to low innate breathing response to hypoxemia, respiratory depressant drugs, or ascent too rapid for adequate acclimatization), poor gas exchange (oxygen for carbon dioxide) in the lungs, fluid retention, individual anatomy (such as ability to accommodate increased brain volume).

As brain volume increases, the pressure within the brain (intracranial pressure, or ICP) rises, although very little (perhaps only 20 to 30 milliliters) until a critical threshold is reached. A dehydrated brain is much more compliant than a “wet” brain. Dilation of cerebral blood vessels causes increased cerebral blood flow and increased cerebral blood volume, engorging the brain and making it stiffer and less compliant. As brain swelling continues, ICP rises beyond the ability of blood to flow into brain tissue. Eventually (and sometimes quite rapidly), cerebral blood flow stops, causing death.

Treatment is directed toward reducing brain volume and stopping any leak of fluid from the blood vessels into brain tissue:

1. Increase oxygenation and thereby reduce low oxygen concentration in the blood and tissues:

a. Descent - 1,000 feet may be adequate to effect improvement, but one should descend as far as is necessary until there is visible clinical improvement.
b. Administer supplemental oxygen if it is available. This is especially good for headaches and altered mental status.
c. Initiate hyperbaric oxygen therapy (e.g., within a portable pressure bag) if such is available

2. Speed the process of acclimatization:

a. Administer acetazolamide (Diamox) 125 to 250 mg by mouth every 12 hours. For children, the dose is 5 mg/kg of body weight/day. This drug promotes increased urination, stimulates ventilation, and decreases cerebrospinal fluid formation. Because acetazolamide carries some cross-reactivity with “sulfa” drugs, it should be used with extreme caution in persons suspected or known to be allergic to sulfa drugs.
b. Acclimatization at the same altitude is okay for mild AMS, but a sick person should never be left alone.

3. Treat symptoms:

a. For the headache, use analgesics.
b. For nausea and vomiting, use antiemetics, such as ondansetron (Zofran) dissolving wafer tablets 4 mg by mouth every 4 hours as needed

4. Reduce the fluid leak from the brain capillaries:

a. Administer dexamethasone 4 mg by mouth (or if a health care professional, by injection) every 6 hours. This may need to be continued until the victim is evacuated to a lower altitude, since rebound brain swelling may occur with cessation of this medication, and because the drug per se does not improve or hasten acclimatization.

Prevention of altitude illness:

1. As best possible, ascend slowly. “Climb high and sleep low.” The ideal rate of ascent is difficult to establish because of marked individual variation in the ability to acclimatize. A reasonable recommendation is to not sleep at an altitude 2,000 feet higher than the previous night’s sleeping altitude once above 8,000 feet. Take an extra day for acclimatization with every 3,000 to 4,000 feet of elevation gain.
2. A high (>70%) carbohydrate diet reduced AMS by 30% in some studies, but had little effect in other reports. It is not likely to be harmful and might help.
3. Avoid respiratory depressants (especially sleeping pills), and only ingest alcohol in small amounts.
4. Chemoprophylaxis:

a. Indications are forced rapid ascent or history of recurrent illness.
b. Take acetazolamide by mouth up to 5 mg/kg body weight/day divided into 2 or 3 doses, beginning one day prior and until one day after ascent. 125 mg twice a day may be sufficient for most persons. Recall that there may be a cross-reactivity (allergic reaction) in persons allergic or sensitive to “sulfa drugs.”
c. Take dexamethasone 4 mg by mouth every 6 to 12 hours, or 2 mg every 6 hrs. This is useful for persons intolerant of acetazolamide, or if the travel will be to extreme altitude. The drug may need to be continued for three or four days, since it does not speed acclimatization. It is commonly used by climbers on “summit day.”
d. Use of acetazolamide and dexamethasone simultaneously is promoted by some - acetazolamide to speed acclimatization and dexamethasone to prevent brain swelling, but only in first few days of ascent.
e. Ginkgo biloba was used in three studies, and shown to reduce AMS from 35 to 100%. It may be more effective during a moderate rate of ascent. The dose is 100 mg by mouth twice a day starting 2 to 3 days before and while at altitude. It is safe and inexpensive, but it has not been proven effective in all studies. Furthermore, preparations of the compound vary.

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

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Thank You to Dr. Deb for Grand Rounds

Thank you to Dr. Deb for including my post about influenza vaccine recommendations for children in this past 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 present them in an informative and entertaining manner.

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WaterGlide

On my recent great white shark adventure aboard the M/V Nautilus Explorer, I was asked to "demo" a new product named WaterGlide™, which is a skin (pump) spray used to facilitate entry into a wetsuit. The major components are a silicone gel and a silicone copolymer. It also has a small amount of cyclomethicone. It contains no alcohol. All of the ingredients are completely inert and hypoallergenic.

According to the manufacturer, High Desert Pharmaceutics, Inc., WaterGlide™ is a multi-sport topical skin lubricant designed to aid the donning and removal of all types of wet suits, dry suits and associated accessories. It is advertised to prolong the usable life of neoprene, latex and other synthetic and natural rubber. It is also advertised to eliminate chafing, abrasion, and uncomfortable rashes on the skin.

I used the product, which most definitely gave my skin a dry, yet extremely slippery sensation. I applied it to my feet, lower legs, hands and arms. It was a tremendous help for me in donning a tight, dry wetsuit. However, it was not nearly as helpful when I used it and attempted to don a wet (and therefore much more "sticky") wetsuit, which was necessary between shark cage entries when I came to the surface to briefly warm up, then re-donned my wetsuit for a repeat entry into the water. I don't believe that WaterGlide™ is really intended for that purpose, so this observation is not a criticism.

I used WaterGlide™ on three successive days for my first entry into the water. Each day, I was underwater for at least 6 hours, and on one day for nearly 8 hours. During the course of those days, I was wearing a full wetsuit with hood the entire time I was underwater. I didn't suffer skin rashes or chafe anywhere that I applied the product. It's not possible to say whether or not the application of WaterGlide™ contributed to that good fortune, but it's worth noting.

Given the difficulty that I usually have pulling on my tightly fitted wetsuits, and the quite noticeable improvement in ease of donning the suit when using WaterGlide™, I intend to continue using the product, and can recommend it to others.

photo by Peter Riekstins

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Flu Vaccine Recommendations for Children

Just recently, the Centers for Disease Control (CDC) expanded its influenza (flu) vaccination recommendation to include children between the ages of six months and 18 years. So, with the exception of infants under the age of 6 months, the recommendation for flu vaccination is approaching one of becoming universal.

Why has this occurred, and what is the relevance for persons who love the outdoors? To answer the first question, I think that we now have an increasing appreciation about the enormous benefits and minimal risks associated with the vaccine(s), and for just how devastating a case of influenza can become. Here is some information about the flu:

The influenza viruses are responsible for seasonal epidemics of the flu, a predominantly respiratory disease. In temperate climates, influenza is a cold weather disease. The illness is recognized by sudden high fever, sore throat, cough, headache, muscle aches, weakness, and occasional (more common in children) nausea with vomiting and/or diarrhea. Influenza is distinguished from a common cold by its intensity, particularly of the headache and muscle aches. The virus is transmitted from person to person via virus-laden large droplets (greater than 5 microns in diameter) generated when infected persons cough or sneeze. “Stomach flu” is a misnomer, because it is not caused by influenza virus, but rather, by other viruses and bacteria.

Elderly or infirm individuals are at greatest risk for becoming severely debilitated or developing complications, such as pneumonia, from influenza. General therapy for the flu is the same as that for a common cold: rest, adequate nutrition, increased fluid intake, and medicine for fever. Vaccines are prepared each year that are somewhat effective in the prevention of types A and B influenza. Oseltamivir phosphate (Tamiflu) is a drug that is used for treatment of influenza types A and B in adults who have been ill for no more than 2 days. It is given in an adult oral dose of 75 milligrams (mg) twice daily for 5 days. The pediatric dose is based on age and weight. For a child age 1 to 12 years: weight less than 15 kilograms (one kilogram equals 2.2 pounds), 30 mg twice daily for 5 days; 15 to 23 kg, 45 mg twice daily for 5 days; 23 to 40 kg, 60 mg twice daily for 5 days; weight greater than 40 kg or age greater than 12 years, 75 mg twice daily for 5 days. An alternative is zanamivir (Relenza) 10 mg inhaled twice a day for 5 days for all ages.

During an epidemic, victims may benefit from the administration of the oral drug rimantadine 200 mg by mouth daily for 5 to 7 days in adults, and 5 mg per kg of body weight per day (up to 150 mg) for 5 to 7 days in children. An alternative is amantadine in a dose of 100 mg twice daily for 5 days in adults, or 2.2 mg per kg of body weight (up to 75 mg) twice daily for 5 days in children. These are available by prescription for the prevention and treatment of type A influenza (they are ineffective against type B). They are associated with several toxic effects and also contribute to emergence of resistance against them by the influenza virus type A.

Avian influenza A (H5N1, which exists in at least 8 subgroups, or “clades”) may be resistant to the adamantane drugs (rimantidine and amantadine), so would be treated with zanamivir or oseltamivir, the former in a dose of 75 mg and the latter in a dose of 150 mg by mouth twice a day for 10 days. This form of influenza is carried and spread by birds, notably poultry and perhaps wild birds. It has been found in other species, such as cats, tigers, leopards, pigs, ferrets, rabbits, rats, and emus, from where it might more rapidly mutate to a form more infectious to humans. Avian flu has a very aggressive profile, with a high (up to 60%) overall mortality rate in human victims. Infected humans show “typical” flu symptoms, followed rapidly by respiratory and multi-organ failure. There is little evidence for mild or asymptomatic human infections. With regard to protective masks, an N95 respirator mask is supposed to have at least a 95% filtration capability at filtering a 0.3 micron droplet, which carries the virus, but not the virus particles individually.

Flu vaccination is being advocated for virtually all children also because recent evidence suggests that children are often flu spreaders. If you have children in school or day care, or who congregate in groups, such as for athletics, you know that this is true. Although most of the people who die from influenza are elders over the age of 65, it is still anticipated that controlling the spread of the disease in the pediatric population will be quite important.

It has been reported that there are no anticipated shortages of flu vaccine for this flu season (2008-2009). If you are in a high risk group (elder, young child, or person with chronic illness), your doctor will almost certainly recommend that you be vaccinated. Since it is impossible to predict when and where the disease will strike, the sooner you receive your immunization, the better.

Influenza vaccine is administered in one or two injections to children and adults in October and November (in the Northern Hemisphere) prior to the flu season (December through March), with a maximum duration of effect of 6 months. Persons 3 years of age or older should receive a single intramuscular injection of 0.5 ml. Children 6 to 35 months of age should receive only 0.25 ml. Children younger than 9 years of age who have never been immunized should receive two doses spaced at least 4 weeks apart.

Persons for whom annual vaccination is especially recommended include:

1. all persons who wish to reduce the risk of becoming ill with influenza or transmitting the disease to others

2. children ages 6 months to 18 years, particularly those receiving long term aspirin therapy who might be at risk for experiencing Reye syndrome

3. all persons ages 50 years or greater

4. women who will be pregnant during influenza season

5. adults and children who have immunosuppression caused by medications or HIV

6. adults and children who have chronic pulmonary (including asthma), cardiovascular (except hypertension), kidney, liver, blood, or metabolic (including diabetes) disorders

7. adults and children with any condition that might compromise respiratory function

8. healthcare personnel

Each year, the vaccine contains the influenza virus strains that are felt to be most prevalent in the United States. Inactivated (killed-virus) influenza vaccine should not be given to those who are sensitive to egg products. “Whole” vaccines should not be given to children under the age of 13 years. Children should be given “split” vaccines, which have been chemically treated to reduce adverse reactions.

A live, attenuated nasal spray vaccine (FluMist) is at least as effective as injected vaccine, and is approved for persons ages 5 to 49 years who are free of chronic illnesses. It is administered as a spray of 0.25 ml into each nostril (0.5 ml total dose). Children ages 5 to 8 years old who have not been previously immunized should receive two doses spaced at least 6 weeks apart. FluMist should not be administered to family members or close contacts of immunosuppressed persons requiring a protected environment.

Amantadine hydrochloride (Symmetrel) and rimantadine are prescription oral drugs that interfere with viral uncoating within living cells and are moderately effective in preventing influenza A. However, because they confer no protection against influenza B, they are not considered substitutes for appropriate immunization.

To answer the second question, it is important to be immunized against influenza because the disease is "a hammer." If you are engaging in outdoor sports, exploration, or other activities, and you are stricken with the flu, you will potentially become seriously ill. In the past, I had the misfortune to spend a winter week in the mountains with the worst headache and muscle aches of my life, a non-immunized victim of influenza. Since then, I would personally much rather have a sore arm (if that...) for a day than run the risk of being taken down for the count by this powerful illness.

image courtesy of Centers for Disease Control

Tags: influenza, flu vaccine, immunization, wilderness medicine, outdoor medicine, healthline

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Thank You to Musings of a Distractible Mind for Grand Rounds

Thank you to Musings of a Distractible Mind for including my post about using ondansetron to assist oral rehydration therapy in this past 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 present them in an informative and entertaining manner. What a wonderful and innovative presentation this week!

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The Manual of Medicine and Horsemanship

Horses are inextricably linked to wild places, as beasts of transportation, burden, and companionship. They are remarkable animals. In the best of situations, they are beautiful and remarkably powerful, revered for their strength and speed. In other less fortunate circumstances, they are agents of injury. A good friend of mine who is an emergency physician in Jackson, Wyoming once told me that if it weren't for horses, he wouldn't see half the number of patients. Having ridden extensively at one time in order to reach my patients, and occasionally for pleasure, I have a healthy respect for sitting atop an animal that is fantastic when it cooperates, but frightening when it is scared or obstinate.

Beverley Kane, M.D. has written an intriguing book entitled The Manual of Medicine and Horsemanship, which describes how medical students and doctors working with horses can be taught patience, gentleness, and respect, emphasizing the power of nonverbal communication and attention to the details of a compassionate approach to other creatures. Dr. Kane is Clinical Instructor and Program Director of Medicine and Horses at Stanford Medical School in Palo Alto, California. She has a private practice, Horsensei Equine-Assisted Learning and Therapy.

Subtitled "Transforming the Doctor-Patient Relationship with Equine-Assisted Learning," The Manual of Medicine and Horsemanship has much to recommend it. It is a blueprint for how to create a course that demonstrates the value of communication in a doctor-patient relationship, and how, specifically, to teach it using the recommended approach. In this regard, the book is excellent and fascinating. In other regards, where superfluous (to this reader) quotes were inserted to analogize certain aspects of the content that stand strongly without embellishment, the author could have been less poetic and more prosaic. Interspersed with the instructions are spiritual-philosophical comments that would have been better consolidated into a commentary session apart from the didactic and instructive elements of the book.

There were aspects of this book that were terrific and others that I hastened to complete, so that I could maintain a thread of continuity in my reading. Dr. Kane makes a good case for the need for young doctors to understand their innate deficiencies in understanding patients, and that better relationships across the board lead to joy and satisfaction in learning and caregiving. Working with horses is a unique approach, and so this book and what is espoused within is quite unique, and in my opinion, highly laudable. Reading about the nuts and bolts of a Medicine and Horses program made me want to participate and learn, which is the highest compliment. As a wilderness medicine physician who has always looked upon his steed as a way to get from the hospital to the outback, and been mostly concerned about not falling off his mount, I understand how horses (and other animals) should be appreciated in an entirely different light, as they have much to teach us. However, I think a note of caution is in order, because while we have much to learn from horses about body language, gestures, and a non-threatening approach, we must take care to recognize that human thoughts and needs add a layer of complexity to the task that often makes it all the more difficult to be an efficient, yet sufficiently communicative, caregiver in our hurried and harried healthcare environment. In other words, learning around horses may be necessary, but it is not sufficient. We need to spend at least as much time in observation around humans as around horses, and learn to recognize the cues and behaviors that lead to acceptably intimate interactions as confidants and doctors.

Tags: horse, horsemanship, equine, wilderness medicine, outdoor medicine, healthline

Labels: horsemanship, medicine, teaching

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Oral Ondansetron to Assist Oral Rehydration Therapy

Oral rehydration can be a lifesaving therapy for persons, particularly children, suffering from dehydration. The most common cause of dehydration in children is infectious diarrhea.

When dehydration occurs, it is important to act swiftly. If fluid losses are significant, begin to replace liquids as soon as you can.

Oral Rehydration Salts (ORS) that meet World Health Organization standards are available in a dry mix; use one packet per quart (liter) of water. One packet contains sodium chloride 3.5 grams, potassium chloride 1.5 g, glucose 20 g, and trisodium citrate 2.9 g (or sodium bicarbonate 2.5 g). Cera Lyte 70 oral rehydration salts are based on a rice solution. One packet is mixed with a quart (liter) of water. After the solution is prepared, it should be consumed or discarded within 12 hours if kept at room temperature or 24 hours if kept refrigerated. Other ORS products available over-the-counter include Pedialyte, Enfalyte, Naturalyte, and Rehydralyte.

1. Mild diarrhea/hydration: Drink soda water, clear juices, broth, and electrolyte-containing sports beverages. If diarrhea is the cause, try to replace each diarrheal stool with 10 milliliters of ORS per kilogram (2.2 pounds) of body weight. If the child is vomiting, try to replace each episode of vomiting with 2 mL of ORS per kg (2.2 lb) of body weight.

2. Moderate diarrhea/dehydration: Drink diluted (by half, with water) electrolyte-containing sports beverages, mineral water (bottled), or a homemade solution (1 quart or liter of disinfected water plus 1/2 to 1 teaspoon, or 1.3 to 2.5 mL, of sodium chloride [table salt], 1/2 tsp of sodium bicarbonate [baking soda], 1/4 tsp, or 0.6 mL, of potassium chloride [salt substitute], and glucose [6 to 8 tsp, or 30 to 40 mL, of table sugar; or 1 to 2 tbsp, or 15 to 30 mL, of honey]). Take care not to over-sweeten (exceed 2 to 2.5% glucose) the solution with sugar, because this may worsen the diarrhea; too high a sugar concentration inhibits water absorption through the gastrointestinal tract. Each quart of this “home brew” should be alternated with 1/2 to 1 quart of plain disinfected water. Try to replace fluid losses at least every 2 hours.

When using ORS, try to get the victim to ingest a quart per hour until the frequency of urination begins to increase and the urine color turns light or clear. To begin, start with small (e.g. 5 mL or one teaspoon) amounts every 1 to 2 minutes, to avoid collection of a large amount of fluid in the stomach that might cause vomiting. A child should be given 11/2 oz (44 mL) of ORS per pound (0.45 kg) of body weight over the first 4 hours, then 1 ounce (30 mL) of ORS per pound of body weight per 8-hour period until the diarrhea resolves. Another estimate of fluid replacement for children is 100 ml (approximately 3 oz) of fluid per significant loose bowel movement. For an infant with diarrhea, decrease the amount of milk in the diet, and add more water, diluted juices, half-strength sports beverages, and ORS. Sweetened carbonated beverages (soda pop) are not good replacement fluids, because they contain too much sugar and little or no sodium and potassium. If the child is breast-fed, keep nursing (offer the breast more often). If the child is formula-fed, use ORS for 12 to 24 hours, then try switching back to formula. If the diarrhea persists switch back to ORS for another cycle. It is important to continue to provide nourishment with food (and calories) to children with diarrhea, not fluid alone. Avoid foods high in simple sugars (including tea, juices, and soft drinks). Try complex carbohydrates (rice, wheat, potatoes, bread, cereals) and yogurt, lean meat, fruits, and vegetables.

If premeasured salts are not available with which to supplement water, you can alternate glasses of the following two fluids, as recommended by the U.S. Public Health Service:

GLASS ONE — 8 oz fruit juice with 1/4 tsp (a “pinch”) table salt and 1/2 tsp honey or corn syrup (237 mL juice, 1.3 mL table salt, 2.5 mL honey or corn syrup)

GLASS TWO — 8 oz disinfected water with 1/4 tsp baking soda (sodium bicarbonate) (237 mL water, 1.3 mL baking soda)

Another homemade fluid mixture is 1 tsp (5 mL) table salt and 1 cup (275 mL) rice cereal in a quart (liter) of water; this must be used within 12 hours or discarded. If only fruit juice (without supplementation) is available, remember to cut it to half strength with water. Otherwise, the sugar content will be too high and may contribute to continued diarrhea. Estimation techniques to measure powdered ingredients (such as a “pinch” of table salt) are notoriously inaccurate, and can even be dangerous if you add excessive amounts. Use a proper measuring implement whenever possible.

3. Severe diarrhea/dehydration: Same as moderate. After a certain point, as with cholera, intravenous hydration may be lifesaving. See a physician as soon as possible.

Sometimes, offering liquids to drink is not sufficient to diminish the nausea and vomiting that accompany an episode of gastroenteritis. If a person cannot ingest sufficient liquid, the diarrhea persists. In a recent article in the Annals of Emergency Medicine (Ann Emerg Med 2008:52:22-29) entitled "The role of oral ondansetron in children with vomiting as a result of acute gastritis/gastroenteritis who have failed oral rehydration therapy: a randomized controlled trial," the authors concluded that in subjects with acute gastritis/gastroenteritis and mild to moderated dehydration who failed initial oral rehydration therapy, the proportion of children who subsequently required intravenous hydration was lower in a group treated with ondansetron (Zofran) in a dose of 0.15 mg/kg body weight of the oral dissolving tablet, as compared to a group that did not receive the drug.

Having suffered nausea and vomiting from acute infectious gastroenteritis while traveling, I can attest to the benefit of ondansetron in providing sufficient relief to allow me to be able to begin to drink liquids and thereby rehydrate. Given that this observation is fairly common among clinicians in the field, and that this study strongly points to a benefit of the drug for children in whom oral rehydration is prevented by persistent nausea and vomiting, it makes perfect sense to carry a drug such as this, with limited side effects, that might allow initiation of essential replenishment of body fluid.

Tags: oral rehydration therapy, ondansetron, dehydration, wilderness medicine, outdoor medicine, healthline

Labels: hydration, nausea, ondansetron, rehydration, vomiting

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Thank You to Nurse Ratched's Place for Grand Rounds

Thank you to Nurse Ratched's Place for including my post about a great white shark adventure in this past 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 present them in an informative and entertaining manner.

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Global Rescue

Travelers around the globe encounter environmental, political, personal, and medical situations in which they require rapid assistance, up to and including evacuation to their country of origin. When an evacuation is necessary, it is not the time to begin research on how this might be accomplished. In this regard, most people are poorly prepared. So, it is important to think now about how you would be rescued, transported, and evacuated in an emergency.

Global Rescue LLC advertises to provide expert medical, security, and aeromedical evacuation services. Headquartered in Boston, Massachusetts, the company notes that "nearly half of all international travelers will report a medical problem this year and 1 in 30 will be hospitalized. Thousands will require medical evacuation costing over $100,000 that is not covered by health or travel insurance."

At the opposite end of the spectrum, Americans are traveling to foreign (to the U.S.) countries, such as India and Thailand, to obtain medical care (in particular, surgical services) at a cost lower than that charged in the U.S. So, if the medical care in other countries is sufficiently high quality to convince Americans to travel abroad for care, why is it so important to have a method for evacuation back to the U.S.?

There are many reasons to plan ahead for medical advice, evaluation, assistance, and evacuation. Furthermore, in this time of security risks up to and including armed conflict, kidnapping, and terrorism, one must be aware of how to get help quickly and reliably, because during or immediately after the event is not the time to begin planning. Global Rescue is one of a group of entities, such as the Divers Alert Network, that have offerings (advice, insurance, etc.) designed to assist the traveler in need (usually medical).

Global Rescue, the Official Provider of aeromedical services to the U.S. Ski and Snowboard team, advertises that if you are hospitalized or in need of hospitalization more than 160 miles from home, it can launch an aircraft and medical team in as few as 90 minutes to initiate the evacuation. Furthermore, it will initiate and complete search and rescue operations using professionals, some of whom have special forces backgrounds. 24/7 medical consultations are offered in English in collaboration with Johns Hopkins University Hospital. Finally the company has the capacity to provide security advisory services and fee-for-service deployable security teams.

Do the research, and decide for yourself how best to procure insurance and make plans for your journeys. But do not count on being able to easily arrange bonafide medical advice or a smooth evacuation if you have not planned in advance. Global Rescue is a good place to start as you become educated on these matters.

Tags: Global Rescue, aeromedical evacuation, security, wilderness medicine, outdoor medicine, healthline

Labels: aeromedical evacuation, evacuation, Global Rescue, security

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