Carbon Monoxide Poisoning

Abstract

The number of deaths from carbon monoxide (CO) poisoning remained constant for many years but has recently started to fall. There are three reasons. Firstly, it has become more fashionable to commit suicide by more sophisticated methods, particularly now that tranquillisers and antidepressants are widely prescribed. Secondly, Britain's domestic gas supply is being changed over from coal gas to natural gas, which contains no carbon monoxide-though so far only an eighth of the country has actually been converted to the new gas. Thirdly, and perhaps most significant, is the changeover which has taken place in the manufacture of gas for domestic use, coal carbonization having given way to oil reforming. Techniques for reducing the amount of CO present have also been introduced, but as G. Thurston' has shown, inadequate combustion or ventilation can be lethal even when the original fuel contains no CO. So in about eight years, when the whole country has been converted to natural gas, there will still be numbers of patients with CO poisoning needing resuscitation.Recently J. S. Smith and S. Brandon2 reviewed 206 episodes of CO poisoning in Newcastle. The mortality rate was 3900. In 20% of patients recovery was complicated by prolonged delirium suggesting that "all degrees of functional or structural neurological damage may have occurred, yet oxygen therapy was given in only 43.8% of suicidal and 32-5% of accidental exposures." They suggest that in view of the risk of persistent neuropsychiatric sequelae current patterns of management should be revised.In selecting a form of therapy there are two aspects to consider: firstly, the prevention of death and, secondly, the reduction of neuropsychiatric sequelae such as those described by H. Garland and J. Pearce.3 Carboxyhaemoglobin should be eliminated as quickly as possible because its presence alters the dissociation curve of the remaining oxyhaemoglobin, impeding oxygen release to the tissues.4 J. S. Haldane5 was the first to describe the use of hyperbaric oxygen in CO poisoning, when he failed to poison a mouse placed in a jar containing two atmospheres of oxygen and one of CO. This was all the more remarkable for the fact that the affinity of haemoglobin for CO is about 250 times that for oxygen. Hyperbaric oxygen keeps the patient's tissues oxygenated by the oxygen physically dissolved in the plasma at a time when his haemoglobin is not available to him for oxygen transport. It is also the most efficient means of reducing the carboxyhaemoglobin level, as was shown by T. A. Douglas and his colleagues6 in 1962 when they compared the efficiencies of oxygen at one atmosphere's pressure, oxygen at two atmospheres' pressure, and of 50/% and 70 % carbon dioxide in oxygen.

Abnormal fingernail beds following carbon monoxide poisoning: a case report and review of the literature

“…Carbon monoxide poisoning is one of the most serious health problems worldwide and refers to the exposure of carbon monoxide levels higher than 3 percent in nonsmokers [2,3]. Fetuses, infants, older persons (especially those with cardiopulmonary diseases), and pregnant women (because of fetal hemoglobin) have a higher affinity than adults for carbon monoxide; they are at more of a risk and show symptoms of toxicity at a lower level of carbon monoxide [2,3,5].…”

“…Fetuses, infants, older persons (especially those with cardiopulmonary diseases), and pregnant women (because of fetal hemoglobin) have a higher affinity than adults for carbon monoxide; they are at more of a risk and show symptoms of toxicity at a lower level of carbon monoxide [2,3,5]. Prolonged exposure to a high level of carbon monoxide during gestation may produce abortion, still birth, low birth weight, delayed brain development, motor disability, microcephaly, and limb malformation [5].…”

“…Carbon monoxide (CO) is a colorless, tasteless, odorless and nonirritating gas [1,2]. It has a high affinity for hemoglobin, 200 to 250 times more than hemoglobin's affinity for oxygen.…”

“…It has a high affinity for hemoglobin, 200 to 250 times more than hemoglobin's affinity for oxygen. Carbon monoxide binds to hemoglobin, forming carboxyhemoglobin, and can shift the oxygen-hemoglobin dissociation curve to the left [2-4]. …”

“…The brain, heart, lungs, kidneys, and other organs that are more susceptible to hypoxia may be critically damaged by carbon monoxide exposure [5]. Signs and symptoms of carbon monoxide poisoning are vague and may be mistaken for a migraine, cerebrovascular accident, psychiatric illness, depression, Parkinson’s disease, gastroenteritis, chronic fatigue syndrome, influenza, alcohol intoxication, and heart disease [2,3]. We describe the first case of acute carbon monoxide poisoning with the fingernail bed effect mentioned above and review the literature regarding carbon monoxide poisoning.…”