Wilderness medical responders prepare for scenarios in extreme conditions

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The two-hour discussion, which earned emergency responders continuing education credits, included injury/ illness case studies, including Paul Marcolini, WEMT-P describing Denali National Park and Mt. McKinley, Alaska medical care in an austere environment, with evacuation considerations and helicopter rescue at high altitudes. The collaborative meets regularly to hone the abilities of local emergency responders to respond through networking and specific search and rescue training.

Alan Sleight, W-A-EMT, led a discussion on evaluation and treatment responses to mild to extreme hypothermia. The moderator was Jacques Belaid, MD.

Marcolini serves with the Denali National Park Ranger Patrol, which sets up a medical base camp at an altitude of 14,200 feet on Denali, so members have the ability to more quickly respond to onmountain emergencies, which average 100 per climbing season during the April-July window, including an average of two fatalities each year.

Available equipment includes oxygen, altitude sickness medications (which have to be kept from freezing) some monitoring equipment and materials and warming bags used to get body temperatures back up.

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The major concerns are frostbite, which could cost a climber fingers or toes; high altitude cerebral edema (brain swelling, which usually requires evacuation down to at least 11,000 feet); high altitude pulmonary edema, particularly when climbers ascend to the 17,000 foot high camp; and occasional injuries sustained from climbers falling into crevices or other accidents. There usually is not the time or resources to respond in the event of a cardiac arrest, Marcolini said.

Most minor emergencies can be handled by self-rescue, Marcolini said, with only about 20 percent of the cases requiring intervention from the medical patrol. The cost of search and rescue operations in national parks nationwide averages $4.2 million annually, with a third of the search and rescues involving less experienced day hikers. One of the high-incidence technical rescue areas includes Niagara Falls.

Members of the medical patrols are highly qualified EMTs or paramedics with specialized wilderness rescue training and familiarity with air transport protocols, Marcolini said. Alan Sleight and helpers showcased the use of a Gamow bag, an inflatable pressure bag large enough to accommodate a person inside. By inflating the bag with a foot pump, the effective altitude can be decreased. It is primarily used for treating severe cases of altitude sickness. Atmospheric pressure is applied and the core body temperature can be raised with the help of thermal heat packs to decrease altitude symptoms. Sleight said a patient will be bundled up under at least four inches of insulation. Once in the Gamow bag, the person appears to be in a cocoon.

In the wilderness environment, emergency responders generally have less equipment with which to respond to emergencies and it may take quite some time to reach the location of the medical emergency, particularly when winter weather conditions prevent an airlift attempt.

Hypothermia is a condition in which the body’s core temperature drops below that required for normal metabolism and body functions. Rescuers do encounter this type of emergency in Franklin County. This temperature is generally considered to be 95°F. Normal body temperature is usually maintained near a constant level of 97.7– 99.5°F. If a person is exposed to cold and their internal mechanisms cannot replenish the heat that is being lost, the body’s core temperature falls, and characteristic symptoms occur such as shivering and mental confusion.

Other cold-related injuries that can be present either alone or in combination with hypothermia include: Chilblains, which are superficial ulcers of the skin that occur when an individual is repeatedly exposed to cold; Frostbite involves the freezing and destruction of tissue; Frostnip is a superficial cooling of tissues without cellular destruction; and trench foot, or immersion foot, is due to repetitive exposure to water at non-freezing temperatures.

The signs and symptoms vary depending on the degree of hypothermia, and may be divided by three stages of severity. With moderate hypothermia, low body temperature results in shivering becoming more violent. Uncoordinated muscles become apparent. Movements are slow and labored, accompanied by a stumbling pace and mild confusion, although the person may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. The subject becomes pale. Lips, ears, fingers and toes may become blue.

With severe hypothermia, as the core body temperature decreases, further physiological systems falter and heart rate, respiratory rate and blood pressure all decrease. This results in an expected heart rate in the 30s at a core body temperature of 82°F. Difficulty in speaking, sluggish thinking, and amnesia start to appear, and the inability to use hands and stumbling is also usually present. Cellular metabolic processes shut down. Below 86°F, the exposed skin becomes blue and puffy, muscle coordination becomes very poor, walking becomes almost impossible, and the person exhibits incoherent/irrational behavior including terminal burrowing or even a stupor. Pulse and respiration rates decrease significantly, but fast heart rates also can occur. Major organs fail. Clinical death can occur when the core body temperature drops below 80°F.

Treatment is matched to the degree of hypothermia, ranging from noninvasive, passive external warming to active external rewarming, to active core rewarming. In severe cases, resuscitation begins with simultaneous removal from the cold environment and management of the airway, breathing and circulation. Rapid rewarming is then commenced. Moving the person as little and as gently as possible is recommended as aggressive handling may increase risks of an arrhythmia (irregular heart beat).

Detecting vital signs in those who are severely hypothermic may be difficult, so it should not be assumed that the person is dead but resuscitation should be continued until the body is warm.

Rewarming can use a number of different methods including passive external rewarming, active external rewarming, and active internal rewarming. In the case of first aid by people who are not medically qualified, gradual rewarming is recommended. Passive external rewarming involves the use of a person’s own ability to generate heat by providing properly insulated dry clothing and moving them to a warm environment, recommended for those with mild hypothermia. Wet clothing should be replaced with dry clothes including a head covering. Emergency services should be called if the person does not improve within a few minutes or worsens.

Active external rewarming involves applying warming devices externally, such as warmed forced air. In extreme environments, hypothermia can be treated by placing a hot water bottle in both armpits and groin, and is recommended for moderate hypothermia. Warming items should not be placed directly against the skin to avoid burns. Active core rewarming involves the use of intravenous warmed fluids, irrigation of body cavities with warmed fluids (the thorax, peritoneal, stomach, or bladder), use of warm humidified inhaled air, or use of extracorporeal rewarming such as via a heart lung machine, the fastest method for those with severe hypothermia but not really available in the field.

Warm sweetened liquids, such as diluted Jello, can be given provided the person is alert and can swallow. With hypothermia, digestion largely shuts down so the person can’t digest anything more until they are warmed up, Sleight pointed out. Alcohol and caffeinated drinks should be avoided. As most people are moderately dehydrated due to hypothermia, intravenous fluids are often helpful, warmed to a temperature of 104–113°F. When the person warms up, he will regain a normal appetite and again be able to handle food.

Rewarming collapse (or rewarming shock) is a sudden drop in blood pressure in combination with a low cardiac output which may occur during active treatment of a severely hypothermic person. External rewarming can increase the risk, so rescuers work at bringing up the core body temperature.

Appropriate clothing helps to prevent hypothermia. Synthetic and wool fabrics are superior to cotton as they provide better insulation when wet and dry. Some synthetic fabrics, such as polypropylene and polyester, are used in clothing designed to wick perspiration away from the body, such as liner socks and moisture- wicking undergarments. Clothing should be loose fitting. In planning outdoor activities in harsh environments, always prepare for possible cold weather.

Covering the head is effective, but no more effective than covering any other part of the body. While common folklore says that people lose most of their heat through their heads, heat loss from the head is no more significant than that from other uncovered parts of the body. However, heat loss from the head is significant in infants, whose head is larger relative to the rest of the body than in adults.

Building a shelter can aid survival where there is danger of death from exposure. Shelters can be of many different types. The shelter should not be too big so body warmth stays near the occupants. Good ventilation is essential, especially if a fire will be lighted in the shelter. Fires should be put out before the occupants sleep to prevent carbon monoxide poisoning. People caught in very cold, snowy conditions can build an igloo or snow cave to shelter.

With water exposure, the U.S. Coast Guard promotes using life vests to protect against hypothermia through the 50/50/50 rule: If someone is in 50°F water for 50 minutes, he/she has a 50 percent better chance of survival if wearing a life jacket. A heat escape lessening position can be used to increase survival in cold water.

In the home, babies should sleep at 61-68°F and housebound people should be checked regularly to make sure the temperature of the home is sufficient.

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