Cold Towels Valuable Rehab Tools

BY GUY W. BULL

Stress/overexertion caused the greatest number of deaths of American firefighters in the line of duty in 2007; the most common nature of death was heart attack, and the majority of heart attacks occurred on the fireground.¹ This pattern of death has persisted for many years. We are now awakening to the risk of core temperature rise from heat stress during firefighting and training operations. Until recently, fire service protection in uniforms, training, and equipment has focused almost entirely on thermal burns. When worn completely on a hot day, the protective uniform ensemble can defeat virtually every thermal regulating mechanism of the human body. Unable to cool itself, the body’s core temperature can rise to a dangerous level in an astonishingly short time. The irony is that as we’ve decreased the risk of injury from thermal burns, we’ve also increased a risk factor for the leading killer of firefighters.

National Fire Protection Association (NFPA) 1585, Standard on the Rehabilitation Process for Members During Emergency Operations and Training Exercises (2008 ed.), addresses issues of core cooling. Get a copy and read it. Your revved-up rehab just might save someone’s life.

Once a firefighter gets hot on a fire scene, the only practical management is core cooling in rehab. Rehydration and passive cooling alone may not manage core cooling for temperatures that have rocketed into dangerous territory within the first 30 minutes of a fire. The big problem with passive cooling is that it loses effectiveness as temperature and humidity risejust when you need to cool the most.

So, how does your rehab cool a hot firefighter on a hot fire scene on a hot and humid day? Is your rehab focusing on rehydration and missing thermal stress? Is administration looking at high-tech and high-cost cooling devices that haven’t been implemented yet? What if you had to rehab hundreds or thousands of victims in a natural disaster like in the sweltering post-hurricane Katrina Superdome?

The common cold towel is an effective adjunct for core cooling. This article explains the science and methodology behind a simple, compact, expandable, and sustainable core-cooling system built around the towel and other commonly available items. Costing only pennies per person, it can be built today and activated tomorrow with minimal training. It is simply an old concept with a touch of modernization.

THE LFR EXPERIENCE

On July 25-27, 2007, the Littleton (CO) Fire and Rescue (LFR) conducted routine training on an acquired structure. The goal was to simulate actual fire conditions. The exercise was conducted in full turnouts and SCBA. There were two main elements: an exterior roof ventilation and an interior hose attack with self-rescue.

Eleven identical exercises were conducted. Crews worked until all tasks were completed (time range was 16 to 27 minutes, one air tank). Air temperature on day 1 was 97°F; on day 2, 87°F; and on day 3, 83°F; a lightning storm and rain cancelled the last training evolution.

This exercise is considered one of a moderate level of heat exposure, because under real fire conditions, the crews could easily work twice as long (two air tanks) in hotter weather and be subjected to additional radiant heat.

Sixty-two firefighters were monitored for core temperature rise. Thirty-three firefighters were found to have a temperature greater than 101°F. Of those 33, 12 were above 102°F, four were above 103°F, and two firefighters registered 103.3°F.

This was an average day on the job for a firefighter. The exercise was typical in all regards. It clearly illustrated the reason firefighters must stay fit and all members participating require real rehab.²

When all tasks were completed, members were directed to the rehab area. Rehab consisted of shade, doffing turnout jackets and pants, a cold towel soaked in ice water, and cold water to drink. The firefighters were allowed to self-regulate their own coolingdrink all the water they wanted and use the towels as they pleased.

Tympanic temperatures were taken just before the rehab process started and again after 15 minutes, using a thermometer that uses disposable ear probe covers and has several elements engineered to ensure accurate measurement. The same instrument was used for all measurements. A control group of six firefighters (0800 hour shift exchange, at rest, in class B uniforms, in air-conditioned station with air temperature 72°F) was found to average a temperature of 97.4°F.

Results:

Of the 33 firefighters who had temperatures greater than 101°F, the average temperature was 98.5°F after 15 minutes of rehab. All 62 members were cooled to 99°F or lower, and all were deemed fit for duty after rehab.
Fifty-three firefighters highly recommended and nine recommended cold towels as a comfort aid (n=62).

HEAT STRESS: HOW WELL ARE WE MANAGING IT?

It is essential that the body maintain its core temperature in a narrow range from 98.6°F ±1.8°F (37°C ± 1°C).³ Core temperature rises whenever the body’s natural cooling mechanisms are overwhelmed by heat stress. Heat stress is the total heat load imposed on the body and results from a combination of factors: internally, from the metabolic result of extreme exertion; and externally, from ambient heat, radiant heat from fire and from protective clothing that traps heat and prevents normal evaporative cooling. (3) Heat stress is unavoidable on the fireground, but it may be significantly more severe than we realize and could potentially force core temperatures to dangerous levels in less than 30 minutes at a difficult fire scene. (3)⁴

Heat strain refers to the adjustments made by an individual in response to the heat stress. These adjustments include biochemical, physiological (such as sweating, flushed skin, tachycardia, and core temperature rise), and psychological processes.⁵ Core temperatures greater than 100.4°F can result in heat illness⁶ and, when present, should be the first stressor managed in rehab. Heat strain adds to and complicates dehydration and exhaustion. The objectives of rehab change with the nature of the weather and the tasks assigned but should remain in this order: core cooling, rehydration, and endurance.

THE IMPORTANCE OF MANAGING HEAT STRESS

Sudden cardiac death is the leading cause of line-of-duty firefighter fatality. Yet, fatalities are just the tip of the iceberg. In 2005, 48 firefighters died of a heart attack, but an estimated 765 firefighters suffered an on-duty cardiovascular event that did not result in sudden death.⁷In June 2007, the National Institute for Occupational Safety and Health (NIOSH) identified heat stress as one of the workplace-related factors associated with an adverse cardiovascular outcome. NIOSH recommends “on-scene rehabilitation … to cool and rehydrate the firefighter.” (7)

The NFPA 1584 rehab standard homes in on the risk of heat stress. Core cooling is now recognized as a problem that must be actively managed. Are the traditional methods used by the fire service for decadeshose streams, ice, wet towels, fans, and mistersgood enough? Do you need to go high tech and high expense?

COOLING METHODS AND THEIR PROBLEMS

Cooling can be accomplished by the following methods:

Evaporation. Water changing from a liquid to vapor state will remove heat. Even warm water will cool if it evaporates quickly. Problem: Evaporative cooling loses its effectiveness as humidity reaches 100 percent, preventing evaporation.
Convection. An air stream directed at an object will draw heat away if it is cooler than the object. Hence, fans and fanning are effective, especially when combined with mist evaporation. Problem:Fanning loses its effectiveness as air temperature rises and must be stopped above 95°F (median skin temperature). Fans also need a power source and are bulky and expensive.
Radiation. Radiant heat loss occurs when a warm object loses heat to its colder environment. Heat load can be reduced by getting into shade or entering a cool, air-conditioned environment. Problem: Shade is a must for rehab; an air-conditioned environment is unrealistic for most fire rehab situations. Suits designed to cool are not yet readily available for fire service use.
Conduction. Conductive cooling occurs whenever the skin comes in contact with a cooler object; it could be cold water, snow, an ice pack, a cold pack, or cold ground. One advantage of conductive cooling is that it works in all temperature and humidity conditions. Problem: If using a cold water hose stream, you would have to have a constant flow and it would soak the protective clothes, rendering them useless.
Drinking cold water or sports drinks. This remains the single most common method of core cooling. It serves the dual purposes of rehydration and cooling. Problem: Frequently, water and sports drinks are stored warm and must be cooled off; otherwise, their only value is in rehydration. Cooling a case of warm drinking water can take more than 20 minutes, which is longer than the typical rehab cycle.
Conductive cooling devices. They use ice or a cold fluidi.e., an ice bag or a cold packin a contained method so that the cooling effect is directed and controlled. In common use, these devices are used for cryotherapy to cool a part of the body such as a sprained joint or a contusion. Problem: Although they can be used for core cooling, they generally are too cold and uncomfortable for routine core cooling. Also, commercial cold packs are expensive and can be used only once.

Other cooling devices have come on the market. Each claims a scientific angle, and each has its advantages and disadvantages. Vacuum-assisted conductive cooling of the palm and forearm immersion in water are examples. Disadvantages are similar to those of misting fans: their cost and the need for support on a fire scene.

COLD TOWEL AS A COOLING DEVICE

A cold towel works by conductive cooling, which is effective in all temperature and humidity conditions. Ice water and cold towels are the most effective methods of cooling exertional heat illness. The American College of Sports Medicine recommends their use.⁸

(1) Three-bucket regeneration system includes sanitizing, rinsing, and regenerating the towels. (Photo by author.)

Among the advantages of the cold towel are the following:

The temperature of the towel is controllable (cool-cold ice water) and is more comfortable than an ice pack/bag.
You control moisture by wringing out the towel. Wrung out, there is no dripping. A damp towel holds a little more than a pound (500g) of water.
The surface area and the location to be cooled are controllable. A cold towel can be used like a commercially made evaporative or conductive cooling device.
A cold towel has strong psychological appeal; it feels good on a hot day.
The system uses only ice, water, bleach, towels, and plastic buckets. These items are inexpensive, are readily available, and can be quickly brought to almost any fire scene. The entire process is controllable, including the water temperature and sanitizing solution concentration.
You can reuse and regenerate the towels. A dry towel absorbs cold water instantly and is immediately available for cooling. A used towel can be soaked in a sanitizing bleach solution for reuse. Twenty towels used in a 20-minute rehab cycle would rehab 60 people in an hour, or 600 in a 10-hour period, all at very little expense. Kept resupplied, this system could run indefinitely.

SUSTAINING COLD TOWEL REHAB

When towels are clean and dry, they can be used immediately for rehab. However, before a towel can be reused for the second round of rehab, it must go through sanitation and rinse cycles, which can be instituted using three buckets.

The three buckets are used to sanitize, rinse, and regenerate the towels.

Bucket 1 contains the sanitizing solution. Add one-fourth cup of bleach per gallon of water; this is the concentration most commonly recommended. ^{9, 10}

Bucket 2 contains clear water to rinse the towels; the goal is to remove any bleach remaining after the sanitation process.

The third bucket contains cold water, which regenerates the conductive cooling effect of the towel and makes it ready for reuse.

Wring out the towels between buckets, and change the water as needed to maintain each bucket’s function.

USE OF COMMUNITY RESOURCES

This cold towel rehab system is based on the premise that ice, water, and bleach are readily available in your community and that a support staff member can quickly go to a store, make a purchase, and return quickly to the rehab area with these items.

Your department should carry the buckets, towels, a small bottle of bleach, and a measuring cup. This way, you can start cool water rehab immediately, even if the water is not very cold.

TERMINATON OF REHAB AND RESTORATION FOR REUSE

At the end of rehab, you can dispose of the ice water and rinse water anywhere. Pour the sanitizing bleach solution down a drain. Bring the towels back to the station for laundering in hot water and a cup of bleach.

LEARNING TO REHAB

There are both art and science in rehab. The art is in making rehab pleasant. The science is in providing the elements needed to effectively combat environmental stressors. An ice cold towel holding 500g of water will remove thousands of calories of heat from a hot person.

If heat stress on the fire scene is unavoidable (and it is), we must have a plan to deal with its consequences in rehab. Organizationally, all fire departments should have a rehab strategy that deals with the stress elements of heat strain, dehydration, and exhaustion.

Conditions for self-rehab are not the same as for medical treatment. Members are consciously controlling their own rehab. They are making rational decisions and self-regulating the amount of cold water they drink and rate at which they drink it and how they use cooling devices.

You should learn the best methods for rehabbing yourself and how to combat the major stressors. You should know when you are getting hot and how to cool off.

•••

You must recognize and manage heat stress and heat strain. LFR fire crews highly recommend a cold towel as a comfort cooling device. The towel system can be sustained indefinitely with ice, water, and bleach.

Endnotes

1. U.S. Fire Administration Firefighter Provisional 2007 Report. http://www.firerescue1.com/news/331673/.

2. Phoenix Fire Department SOP: Rehab 202.08: “After allowing 20 minutes for a cooling down period … Anybody with temp >101 … IV fluids and transport.” http://phoenix.gov/FIRE/20208.html

3. Occupational Exposure to Hot Environments, Revised Criteria 1986; NIOSH, U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, 1, 2, 18. http://www.cdc.gov/niosh/pdfs/86-113a.pdf

4. Body Temperature Rise During Exercise: Heat Production During Exercise: “During exercise at an intensity equivalent to about 80-90% of a person’s maximal oxygen uptake (VO2max), the body’s heat production in a fit individual may exceed 1000 W, which could potentially cause core body temperature to increase by 1oC every 5-8 minutes if there were no changes in the body’s heat dissipation mechanisms.” http://www.medicdirectsport.com/exercisetheory/default.asp?step=4&pid=46

5. Heat Stress in Mining, U.S. Department of Labor, Mine Safety and Health Administration, Safety Manual #6, http://www.msha.gov/s&hinfo/heatstress/manual/heatmanual.HTM

6. OSHA Technical Manual, Section 3, Chapter 4, Heat Stress. http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_4.html#1

7. Preventing Fire Fighter Fatalities Due to Heart Attacks and Other Sudden Cardiovascular Events, NIOSH publication #2007-133: June 2007, http://www.cdc.gov/niosh/docs/2007-133/#sum

8. Exertional Heat Illness during Training and Competition, American College of Sports Medicine, Position Stand, 2007, 561, http://www.acsm-msse.org/pt/pt-core/template-journal/msse/media/0307.pdf

9. CDC Disaster Safety, Keep Food and Water Safe after a Natural Disaster or Power Outage, September 2, 2005, recommends 1 cup/5 gallons of water as a sanitizing solution. http://www.bt.cdc.gov/disasters/pdf/foodwater.pdf

10. Water Quality and Health Chlorine Bleach: Helping to Manage the Flu Risk 2007 recommends ¼ cup/gallon (1 cup/4 gallons of water) as a sanitizing solution. http://www.waterandhealth.org/flu/disinfect.html

GUY W. BULL, BA, paramedic, is an EMS captain with Littleton (CO) Fire Rescue. He has a B.A. in psychology from San Francisco State University. He has worked for the Los Angeles (CA) Fire Department, the University of California at Santa Barbara Rescue Service, and Aurora (CO) Fire Rescue before joining Littleton as its training/QA officer in 2003. He has been a paramedic, an EMS instructor, and an ocean search and rescue boat service supervisor during an EMS career that began in 1976.