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.

Carbon Monoxide Poisoning

“…The timely administration of HBO prevents neuronal injury, prevents delayed neuropsychological sequelae and terminates the biochemical deterioration. [21][22][23]. Suggested indications for HBO therapy in CO poisoning are given in Table 5.…”

Convergence Analysis of Backpropagation Algorithm for Designing an Intelligent System for Sensing Manhole Gases

“…Safety limit of the manhole gases are as follows. Safety limit of NH 3 is laying between 25 -40ppm (as per limit set by World Health Organization), CO is in between 35 -100ppm [40,41,42], H 2 S is in between 50 -100ppm [43,44], CO 2 is in between 5000 -8000ppm [42,45] and CH 4 is on between 5000 -10000 ppm [46].…”

Flammable Evaluation of Plastics for Living by Cone Calorimeter Test

“…Ernst 등은 CO가 Carboxyhemoglobin (COHb)을 형성하여 저산소증을 일으키고 Oxyhemoglobin의 해리를 일으킨다고 하였다 (26) . CO와 마찬가지로 이산화탄소(CO2)도 화재 시 발생하며, Purser는 5% 이하의 CO2가 호흡을 자극해 호흡 량을 증가시킨다고 하였다 (27) .…”