HOW HBOT CAN HELP
SMOKE INHALATION
Carbon monoxide (CO) and hydrogen cyanide (HCN) are chemical asphyxiants commonly present in fire smoke and should be considered in all cases of smoke inhalation. Both substances interfere with the body’s ability to deliver and utilize oxygen at the cellular level, posing serious risks during exposure.
Carbon monoxide is produced when carbon-containing materials—such as wood or hydrocarbon fuels like gasoline or diesel—burn incompletely due to insufficient oxygen. CO is particularly dangerous because it is colorless, odorless, tasteless, and initially non-irritating, making exposure difficult to detect without monitoring equipment.
Once inhaled, CO binds tightly to hemoglobin, forming carboxyhemoglobin (COHb). This binding significantly reduces hemoglobin’s ability to transport oxygen. Because oxygen dissolves poorly in blood plasma under normal conditions, elevated COHb levels can result in reduced oxygen delivery to tissues and systemic hypoxemia.
Hydrogen cyanide is released during the combustion of nitrogen-containing materials such as green wood, cotton, wool, paper, silk, and tobacco. Cyanide interferes with cellular oxygen utilization, disrupting normal metabolic processes. In fire environments, it is generally assumed that both CO and HCN are present, creating combined challenges related to oxygen transport and oxygen use at the cellular level.
Cyanide toxicity can pose an immediate danger at much lower concentrations than CO. For this reason, first responders must exercise caution and utilize appropriate protective equipment, such as self-contained breathing apparatus (SCBA), when operating in smoke-filled environments.
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Immediate Supportive Care for Smoke Inhalation
The primary priority in managing individuals exposed to smoke inhalation is maintaining a clear and functional airway. Patients with compromised breathing may require assisted ventilation using appropriate airway adjuncts and high-concentration oxygen delivery.
For individuals with a patent airway, high-flow supplemental oxygen is commonly administered using a tight-fitting mask to maximize oxygen delivery. The goal of initial care is to increase the fraction of inspired oxygen and support oxygen availability while further evaluation and treatment decisions are made.
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Oxygen Therapy & Supportive Use of Hyperbaric Oxygen
Providing the highest feasible concentration of oxygen is a foundational component of supportive care for suspected carbon monoxide exposure. Breathing room air, the half-life of CO bound to hemoglobin is approximately 5.5 hours. Administration of 100% oxygen can significantly shorten this timeframe, helping the body eliminate CO more efficiently.
In more severe cases, hyperbaric oxygen therapy (HBOT) may be considered in accordance with established medical guidelines and local protocols. HBOT involves delivering oxygen at pressures greater than atmospheric pressure, which increases the amount of oxygen dissolved directly into the blood plasma. This process can help support tissue oxygenation while CO is being displaced from hemoglobin.
At higher pressures, HBOT has been shown to further reduce the half-life of carboxyhemoglobin. By enhancing plasma-based oxygen delivery, HBOT may help support cellular metabolism during the period in which oxygen transport by hemoglobin is impaired.
Not all medical facilities are equipped with hyperbaric chambers, and clinical opinions regarding HBOT may vary. Decisions regarding its use are made by medical professionals based on patient presentation, severity of exposure, and established protocols. Familiarity with regional guidelines and referral centers is essential.