Smoke Inhalation: An Epidemic?
Smoke is everywhere and the fire service knows it. But is there a thorough understanding of what's in the smoke or why people die from some inhalation?
In 2009, fire departments responded to 1,348,500 fires, a decrease of 7.1% from the year before; however, there were 3,010 civilian fire deaths, which was an increase of 9.3%.1 This begs the question: If fires have decreased, why have civilian deaths increased?
The answer is both simple and complex. Understanding today's fire smoke is far different from that of 10-15 years ago is the first step to comprehending that tactical changes are required, both on the fireground and in the medical treatment of the smoke inhalation victim.
The extensive commercial and residential use of synthetic materials (plastics, nylons and polymers such as Styrofoam and polyurethane foam) have a significant impact on combustion and fire behavior, as well as the smoke produced during a structure fire. The majority of these materials are carbon-based, bonded with various atoms like hydrogen, nitrogen, chlorine and sulfur. Synthetic substances ignite and burn fast, causing rapidly developing fires and toxic smoke and making structural firefighting more dangerous than ever before, and most important, more deadly for civilians in those fires.
Let's look at a mattress fire in a small bedroom as an example of the toxicity firefighters routinely encounter at a structure fire. Polyurethane foam is the most predominant substance in a typical mattress and contains several chemicals--polyol, toluene, methylene chloride and ammonia-based catalysts. When polyurethane foam is exposed to heat, the parent substances break down and bond with each other, creating other new compounds. Some of those compounds are irritants, such as hydrogen chloride and ammonia. Other compounds, like carbon monoxide and cyanide, are toxic when inhaled. Carbon monoxide is created when carbon and hydrogen bond, which is partly responsible for incapacitating a smoke inhalation victim. Cyanide, formed by carbon-hydrogen-nitrogen bonding during the combustion process, disrupts the body's ability to use oxygen and causes asphyxia at the cellular level.
Earlier this year, the Congressional Fire Services Institute's (CFSI) National Advisory Council (NAC) passed A Resolution to Address a New Epidemic: Smoke Inhalation. In its resolution, CFSI notes that there is mounting proof, obtained through atmospheric monitoring on firegrounds throughout the U.S., that hydrogen cyanide (HCN) is a predominant toxicant found in fire smoke. The resolution calls for educating the fire service about the dangers of smoke inhalation--including those of HCN--through support of a national education program, the development of HCN poisoning treatment protocols for all local and state emergency medical services (EMS), and efforts by the Centers for Disease Control and Prevention (CDC) to establish a national database of smoke inhalation injuries, medical complications and deaths linked to HCN.
In fire smoke, hydrogen cyanide can be up to 35 times more toxic than carbon monoxide,2 an underappreciated risk that can cause severe injury or death within minutes.3,4 In a review of major fires over a 19-year period, cyanide was found at toxic-to-lethal levels in the blood of approximately 33% to 87% of fatalities.5 The Fire Smoke Coalition has started working with various government agencies and medical associations in an effort to reduce the number of smoke inhalation deaths by elevating awareness surrounding hydrogen cyanide as the most deadly toxicant in fire smoke, which is treatable if detected, either through atmospheric monitoring on every fire ground scene or a presumptive diagnosis in the pre-hospital environment. As a first step to address the issue, in 2011, the Fire Smoke Coalition launched Aftermath, a 25-minute training video for EMS providers, strictly focused on new considerations for smoke inhalation, most specifically:
- Understanding smoke inhalation as a complicated illness
- The Toxic Twins: HCN & CO and their cumulative physiological impact on the human body
- In-depth discussion about the only two cyanide antidotes approved by the FDA, namely, Cyanokit a/k/a Hydroxocobalamin and the CAK (Cyanide Antidote Kit), and most important, contraindications associated with the later
- Dr. David Persse, medical director, Houston Fire Department, details life saves, both firefighter and civilian, after changing their approach to smoke inhalation treatment in the pre-hospital environment
- Dr. Mike McEvoy details countywide changes made within his response area to include the consideration for cyanide poisoning in some inhalation victims and they have realized lives saved as an end result.
Aftermath is a comprehensive training program that all first responders should. It contains the most current information about hydrogen cyanide in fire smoke and should be taken seriously by all those who provide treatment. Collectively, if a new approach for treatment of the smoke inhalation is embraced and adopted, lives will be saved. To preview the program, click here.
The entire program is available for free download at www.FireSmoke.org.
1. United States Fire Administration. Fire Loss in the United States in 2009.
2. Tuovinen H, Blomqvist P. Modeling of hydrogen cyanide formation in room fires. Brandforsk project 321-011. SP Report 10. Böras, Sweden: SP Swedish National Testing and Research Institute; 2003.
3. Guidotti T. Acute cyanide poisoning in prehospital care: new challenges, new tools for intervention. Prehosp Disaster Med 21(2):S40-S48, 2006.
4. Eckstein M, Maniscalco PM. Focus on smoke inhalation--the most common cause of acute cyanide poisoning. Prehosp Disaster Med 21(2):S49-S55, 2006.
5. Alarie Y. Toxicity of fire smoke. Crit Rev Toxicol 32(4):259-289, 2002.