Hyperbaric Oxygen in the Manitowoc, WI Carbon Monoxide Incident

We have been blogging about the Manitowoc, WI carbon monoxide incident that was so severe it left three people unconscious and caused levels of more than 100 ppm at the entrance. The carbon monoxide poisoning affected both the cafe on the lower level and the apartments on the upper level. Red Cross was called in to find people a place to stay while the source of the carbon monoxide was found and fixed by firefighters.

The Manitowoc, WI carbon monoxide incident was considered a mass casualty event. First responders from other local departments had to come in and help. In addition to St. Luke’s, the victims were taken to two other local hospitals. Four of the people taken to St. Luke’s were treated in a hyperbaric oxygen chamber.

Hyperbaric oxygen therapy involves being treated with 100 percent oxygen while in a pressurized chamber. The therapy has been found to be instrumental in treating acute carbon monoxide poisoning. Using this treatment, the blood can be hyperoxygenated by dissolving oxygen within the plasma.

Carbon monoxide binds to hemoglobin with 200 times the affinity of oxygen. The hyperbaric oxygen treatment is based on the theory that oxygen competitively displaces carbon monoxide from hemoglobin, the red protein responsible for transporting oxygen in the blood. While breathing regular air, the displacement of CO by oxygen would take approximately 300 minutes. While under 100 percent normobaric oxygen, the process would be shortened to 90 minutes. When using hyperbaric oxygen treatment, the process is shortened even further to 32 minutes.

The treatment has been demonstrated as a way to prevent delayed neurological sequelae, as shown in the paper by Lindell Weaver and colleagues in the New England Journal of Medicine in 2002. Hyperbaric oxygen, but not normobaric oxygen, restores cytochrome oxidase aa3/C, a terminal enzyme of the respiratory chain of mitochondria. It also helps to prevent lipid peroxidation, the oxidative degeneration of lipids.

It increases dissolved oxygen content in the blood and eliminates CO from the blood quicker. It also preserves ATP levels in tissue exposed to carbon monoxide. ATP is a small molecule used in cells as a coenzyme.

The main candidates for hyperbaric oxygen treatment after acute carbon monoxide poisoning are pregnant females, because the woman usually has a carboxyhemoglobin level 10 to 15 percent lower than the fetus. Other candidates include those with cardiovascular dysfunction and those who present signs of serious intoxication. These include loss of consciousness for any amount of time, neurologic signs, or severe acidosis, when your kidneys and lungs can’t keep your body’s pH in balance, which can cause shock and death. Many patients with carboxyhemoglobin levels of 25 to 30 percent are treated using hyperbaric oxygen therapy.