HBO Emergencies: Carbon Monoxide Poisoning Carbon Monoxide Poisoning is an all too commonly encountered Hyperbaric Medicine Emergency. Carbon monoxide poisoning is an adverse consequence of house fires, leaky furnaces, the use of combustion engines indoors, indoor barbecuing and sadly suicide attempts. Carbon monoxide is a colorless odorless gas which binds to hemoglobin 240 times the affinity of oxygen.  CO activates destructive enzymes within the body and paralyzes  cellular respiration.  Body organs with high oxygen consumption such as the heart and brain are especially vulnerable. Carbon monoxide poisoning has a wide range of clinical presentation.  Mild cases may present with a headache while more severe cases are associated with consciousness and more severe neurologic signs.  Mild cases may be treated with the UCLA protocol of 4 to 6 hours of 100% oxygen breathing via a nonrebreather mask.  More severe cases require hyperbaric oxygen therapy (HBO). Clinical signs and symptoms at first presentation are more important than the CO level in determining treatment. The recommendation is to treat patients with the greatest morbidity and mortality with hyperbaric oxygen as defined by the presence of at least 1 of 5 possible criteria: 1. Transient or prolonged unconsciousness 2. Abnormal neurological evaluation 3. Cardiovascular dysfunction 4. CO level greater than 25% or 10% in a pregnant woman 5. Significant metabolic acidosis Hyperbaric oxygen use in significant carbon monoxide injury results in a 42% reduction of the long-term neurologic sequela associated with this poison. HBO Saves Lives and Limbs Web Site Designed and Created by Robert David Tufft MD