Carbon Monoxide Poisoning and Smoke Inhalation

Carbon Monixide and Smoke Inhalation

2014 Jul-Aug;41(4):339-54.

Hyperbaric oxygen therapy for carbon monoxide poisoning.


Despite established exposure limits and safety standards, and the availability of carbon monoxide (CO) alarms, each year 50,000 people in the United States visit emergency departments for CO poisoning. Carbon monoxide poisoning can occur from brief exposures to high levels of CO, or from longer exposures to lower levels. Common symptoms include headaches, nausea and vomiting, dizziness, general malaise, and altered mental status. Some patients may have chest pain, shortness of breath and myocardial ischemia, and may require mechanical ventilation and treatment of shock. Individuals poisoned by CO often go on to develop neurological problems, including cognitive sequelae, anxiety and depression, persistent headaches, dizziness, sleep problems, motor weakness, vestibular and balance problems, gaze abnormalities, peripheral neuropathies, hearing loss, tinnitus and Parkinsonian-like syndrome. While breathing oxygen hastens the removal of carboxyhemoglobin (COHb), hyperbaric oxygen (HBO2) hastens COHb elimination and favorably modulates inflammatory processes instigated by CO poisoning, an effect not observed with breathing normobaric oxygen. Hyperbaric oxygen improves mitochondrial function, inhibits lipid peroxidation transiently, impairs leukocyte adhesion to injured microvasculature, and reduces brain inflammation caused by the CO-induced adduct formation of myelin basic protein. Based upon three supportive randomized clinical trials in humans and considerable evidence from animal studies, HBO2 should be considered for all cases of acute symptomatic CO poisoning. Hyperbaric oxygen is indicated for CO poisoning complicated by cyanide poisoning, often concomitantly with smoke inhalation.


Hyperbaric Oxygen for Acute Carbon Monoxide Poisoning

Lindell K. Weaver, M.D., Ramona O. Hopkins, Ph.D., Karen J. Chan, B.S., Susan Churchill, N.P., C. Gregory Elliott, M.D., Terry P. Clemmer, M.D., James F. Orme, Jr., M.D., Frank O. Thomas, M.D., and Alan H. Morris, M.D.

Carbon monoxide poisoning is a serious health problem resulting in approximately 40,000 visits to the emergency department annually in the United States. Unfavorable cognitive sequelae (problems with memory, attention or concentration, and affect) can occur immediately after exposure and persist or can be delayed, but they generally occur within 20 days after carbon monoxide poisoning.Cognitive sequelae lasting one month or more appear to occur in 25 to 50 percent of patients with loss of consciousness or with carboxyhemoglobin levels greater than 25 percent. The recommended treatment for acute carbon monoxide poisoning is 100 percent normobaric oxygen commonly delivered from a reservoir through a face mask that prevents rebreathing. Hyperbaric-oxygen therapy is often recommended for patients with acute carbon monoxide poisoning, especially if they have lost consciousness or have severe poisoning.

Advantages of treatment with hyperbaric oxygen include increased dissolved-oxygen content in blood and accelerated elimination of carbon monoxide. Potential benefits of hyperbaric-oxygen treatment include prevention of lipid peroxidation in the brain and preservation of ATP levels in tissue exposed to carbon monoxide. Disadvantages of hyperbaric-oxygen therapy include risks associated with the transport of the patient to a treatment center, hyperoxic seizures and barotrauma. It is difficult to establish the benefit–risk ratio of hyperbaric-oxygen treatment for the purposes of clinical decision making because the published results are conflicting. We conducted a double-blind, randomized clinical trial to compare the rate of cognitive sequelae in patients with carbon monoxide poisoning treated with hyperbaric oxygen with the rate in those treated with normobaric oxygen.

N Engl J Med 2002; 347:1057-1067October 3, 2002DOI: 10.1056/NEJMoa013121

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Additional indications for hyperbaric oxygen therapy may be discussed with your doctor and the Hyperbaric Medicine Team. Hyperbaric oxygen  therapy is usually used as an adjunct to additional care the patient is receiving. Additional treatments may also include antibiotic therapy, nutritional support, and surgical procedures, if indicated.  Our Hyperbaric Medicine Team will work closely with your physician(s) to coordinate any additional care needed.

Contact the Department of Hyperbaric Medicine at MemorialCare, Long Beach Medical Center for more information.


MemorialCare, Long Beach Medical Center
Department of Hyperbaric Medicine
2801 Atlantic Avenue
Long Beach, California 90806

Telephone: (562) 933-6960

 Fax: (562) 933-6060