136 Smoke Inhalation
• The majority (50% to 80%) of deaths attributable to fire are caused by smoke inhalation rather than burns.
• Smoke is a combination of heated particles and gases (toxicants).
• Carbon monoxide has been implicated in more smoke inhalation deaths than any other single compound.
• In addition to inhalation of toxicants, smoke inhalation can cause upper airway burns that result in pulmonary parenchymal injury.
• The mainstay of treatment consists of ventilator support, early intubation, optimization of fluid resuscitation, pulmonary hygiene, and treatment of specific toxicants.
Epidemiology
Fires are common events in the United States. It is estimated that fire departments respond to fire alarms every 20 seconds.1 In 2007, more than 1 million fire incidents and nearly 3500 deaths were reported, with civilian fatalities occurring every 153 minutes on average.1 An estimated 50% to 80% of fire-related deaths are the result of smoke inhalation. Incident after incident, most of the victims of fires in commercial buildings, such as clubs, escape burns but suffer from smoke inhalation
Smoke inhalation injuries related to fire result from the toxic gases generated. Deaths from smoke inhalation have increased in recent years because of the abundant use of newer synthetic material in building and furnishings.2
Pathophysiology
Deaths from fires are most often caused by smoke inhalation.3,4 The injury from smoke inhalation is a result of direct thermal injury to the airway and lung parenchyma, as well as mucosal irritation, corrosive injuries, and asphyxiation from toxic gases. Toxic gases can be classified as irritant gases and asphyxiants. The danger from such toxic gases predominates in exposed fire victims. Smoke is composed of a complex mixture of suspended small particles, fumes, and gases. More than 400 toxic compounds have been demonstrated in the smoke of a typical house fire. Polyvinyl chloride, a component of many plastic goods, generates at least 75 different toxic products when burned. Of these toxic substances, carbon monoxide (CO) appears to be the most common fatal substance associated with fire victims.5,6
Cyanide is a highly toxic chemical. Hydrogen cyanide is a common by-product of the pyrolysis of wool, silk, and plastics. Cyanogenic compounds such as nitriles are used in industry as solvents and adhesives and are metabolized by the body to cyanide. Acetonitrile, which in the past was commercially available as an artificial nail glue remover, has resulted in fatality when accidentally ingested.7 With increasing concern about terrorism, it is high on the potential lists of chemical agents. Its mechanism is binding of the cytochrome aa3 site on the electron transport system of mitochondria. The result is an inability to use oxygen and subsequent cellular asphyxia.