Hyperbaric oxygen treatment for carbon monoxide poisoning in pregnancy: a case report.

Carbon monoxide (CO) poisoning is one of the most common forms of poisoning in the United States. When CO poisoning occurs in the pregnant patient, it is extremely toxic to the mother and fetus in terms of central nervous system disorders and delayed central nervous system sequelae. Controversy exists in treating the pregnant patient with hyperbaric oxygen (HBO) because of the unknown effects of high partial pressures of oxygen on the fetus. HBO therapy is beneficial in CO poisoning because of its effect of first increasing oxygen concentration and causing a shift in the oxygen dissociation curve from the left to the right. Second, by causing a diminished CO interaction with cytochrome oxidase, HBO allows mitochondria to use oxygen more effectively. Third, HBO may reduce lipid peroxidation which may be responsible for neurological deterioration and delayed central nervous system sequelae. Fourth, decreased CO influence through HBO may reduce changes in the myocardium as a result of CO poisoning, if cardiovascular disease is already present. A case study of successful HBO therapy used during pregnancy is presented and effects of CO on the fetus are discussed.