Smoke inhalation is a caustic event that can be lethal. In the United States, there are more than 23,000 cases and between 5,000 and 10,000 deaths from smoke inhalation each year. Thirty percent of patients treated at burn centers have experienced smoke inhalation.
The presence of burns should increase the provider’s level of suspicion for inhalational injury. In more than half of the cases in which a patient has burns to the nose, lips, eyebrows and neck area, there is some form of respiratory injury. In situations that involve a structure fire and burns to a patient, it is estimated that more than three-quarters of related deaths are due to smoke inhalation and not the burns. In cases where a patient sustains a burn but does not experience smoke inhalation, the mortality rate is less than 2%. When burns and smoke inhalation are both present, mortality rates can exceed 25%.1–3
Overview of Smoke Inhalation
Smoke is a product of combustion (fire) that consists of a mixture of heated particles, chemicals and gases. The specific contents of smoke will vary, depending on location of the fire and what is burned. Examples include: vegetation in forest fires, wood and synthetic material in enclosed structure fires, plastics and metals in burning cars or Dumpsters, and toxic chemicals in industrial fires. In the prehospital setting, it can be difficult to determine the exact makeup of smoke, as many factors contribute to its composition. This not only includes the material being burned, but also availability of oxygen and the fire’s maximum temperature.1–3
Smoke inhalation occurs when an individual inhales smoke through their nose, mouth or both. The effects of smoke inhalation include simple asphyxiation, chemical asphyxiation, simple and chemical irritation, and thermal damage. Because of this, it is important to recall that smoke is more than the visible gray or ashen-white cloud that is associated with a fire. Smoke includes particles of the incinerated material and extreme heat associated with the fire. The heat alone can cause very serious injury.1–3
In addition to recognizing the potential for smoke inhalation, providers should not underestimate the potential effects and impact of inhalation injuries. It has been noted that smoke inhalation injuries can influence patient outcomes more than the patient’s age or burned body surface area. When responding to incidents that may involve smoke inhalation, providers will need to recall the mechanisms that are involved, as well as the associated signs and symptoms in an effort to rapidly identify potential smoke inhalation cases.3
In many situations, the oropharynx, nasopharynx and upper airway can help limit the inhalation of particulate materials and diffuse the heat of the inspired air. The upper airway provides structures (e.g., nasal hair) and mechanisms (e.g., sneezing) to remove solid particles before they can pass deeper into the airway. The upper airway can also limit the exposure to heat. In most situations, such as when participating in physical activity during an athletic event in hot weather, this mechanism is effective. However, because the heat associated with the smoke from a fire can be extreme, normal protective mechanisms are often overwhelmed and extensive airway anatomy damage can occur, including tissue irritation, injury and complete destruction. For these reasons, always anticipate that excessive heat was involved. Providers will need to remain attentive to the potential for immediate and delayed airway compromise.1–8
Asphyxiation involves complex events that result in tissue hypoxia, which occurs when there is a reduced delivery of oxygen to the tissues. For example, in simple asphyxia, fire in an enclosed room may consume the majority of oxygen available in the room’s air. There will therefore be less oxygen available for the individual to inhale. The individual may have adequate or sufficient circulation and oxygen-carrying capability; however, the reduced concentration of oxygen in the room’s air can lead to an insufficient amount for the body’s tissues and cells.2,3,7