The Fate of Co in the Body During Recovery From Mild Carbon Monoxide Poisoning in Man

Roughton, F. J. W.; Root, Walter S.

doi:10.1152/ajplegacy.1945.145.2.239

Cited by 52 publications

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“…The actual time of half elimination of carbon monoxide from the blood, when breathing oxygen, was in this, and in similar experiments, from 45 to 55 min, in reasonable agreement with the observations of Roughton & Root (1945 Fig. 2, wherein about the same total amount of carbon monoxide was administered as in Fig.…”

Section: Resultssupporting

confidence: 90%

“…It is seen that the administration of 100% oxygen over the period 170-194 min (from the start of the experiment) leads to a relatively rapid elimination of carbon monoxide, with a considerable drop in the visual threshold. The actual time of half elimination of carbon monoxide from the blood, when breathing oxygen, was in this, and in similar experiments, from 45 to 55 min, in reasonable agreement with the observations of Roughton & Root (1945). Switching the subject to carbogen increased the rate of carbon monoxide elimination (regarded as an exponential process) to about 21 times the rate when breathing oxygen; the visual threshold showed a further marked decrease.…”

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The time course of the effects of carbon monoxide on visual thresholds

Halperin¹,

McFarland²,

Niven³

et al. 1959

The Journal of Physiology

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During the past few years there has been a revival of the controversy as to the relative merits of oxygen and of oxygen-carbon-dioxide mixtures (93% 02+7% C02, or 95% 02+5% C02) in resuscitation from carbon monoxide poisoning (Marriott, 1955; Hill, 1956). This debate has stimulated a renewed interest in the effects of carbon monoxide on man, and has therefore prompted us, in the present paper, to describe and discuss a number of observations, made in 1944 and 1945, on the prolonged effects of carbon monoxide on vision. The data have not hitherto been published in any detail, though they were presented verbally in preliminary form in 1947(Halperin, Niven, McFarland & Roughton, 1947. The data, now to be reported, were obtained in the latter stages of a research project by McFarland, Roughton, Halperin & Niven (1944), the earlier results of which were published in full at the time.In this paper McFarland, Roughton, Halperin & Niven compared the effects on visual discrimination of the anoxia produced (i) by mild degrees of carbon monoxide poisoning (i.e. carbon monoxide anoxia) and (ii) by hypoxic anoxia caused by breathing gas mixtures containing subnormal partial pressures of oxygen. The apparatus used in their tests was the visual discriminometer of Crozier & Holway (1939), which proved especially suited for studying quantitatively the effects of anoxia on normal men (McFarland, Halperin & Niven, 1944). The same procedure was also used for the observations recorded in the present paper and is briefly described later. With this method McFarland, Halperin & Niven found that the 'immediate' effect of a given amount of carbon monoxide in the blood was about the same as that produced by an equivalent amount of oxygen unsaturation in the arterial blood, the effect of the carbon monoxide anoxia being roughly twice as great as in many other physiological tests. They did not, however, examine closely the time course of the effects of carbon monoxide anoxia on visual discrimination. But 584 M. H. HALPERIN AND OTHERS a study of their data from this point of view suggests some significant differences from the effect of hypoxic anoxia. In the present paper it is shown that the difference between the two types of anoxia becomes very manifest when the time course of recovery from each of them is compared. The effect of carbon monoxide is found, indeed, to persist for a remarkably long time, even when compared with its slow rate of disappearance from the blood, whereas the recovery from the visual effects of hypoxic anoxia takes place within a few minutes when 100% oxygen is breathed. Prolonged effects of carbon monoxide have often been observed clinically and specific histological lesions in the central nervous system have also been seen in post-mortem examinations after deaths from carbon monoxide poisoning. The experiments to be described in the present paper, on the effects of breathing oxygen at various pressures during the recovery period, not only support this concept qualitatively, but also give some direct quantitativ...

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Section: Resultssupporting

confidence: 90%

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confidence: 90%

The time course of the effects of carbon monoxide on visual thresholds

Halperin¹,

McFarland²,

Niven³

et al. 1959

The Journal of Physiology

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“…This "slowly equilibrating CO space" could consist of CO bound to hemoglobin in an intravascular stagnant blood pool, or CO bound to cytochrome or other compounds in slowly perfused body tissues. Myoglobin is know to bind CO; however, all or most of the myoglobin CO has been thought to be in equilibrium with blood CO (13). In fact, the presence of rapidly equilibrating myoglobin CO binding sites is thought to explain the higher blood volume measurements obtained with the CO method than found with isotope (14, 15) or dye (16) methods.…”

Section: Discussionmentioning

confidence: 99%

Endogenous Carbon Monoxide Production in Man*

Coburn¹,

Blakemore²,

Forster³

1963

J. Clin. Invest.

232

131

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Since the late 19th century, carbon (CO) has been known to be present in of normal man and animals. The origin in blood, however, has not been entirely Although it might be assumed that all CO is absorbed from the environment, thors have thought that some, at least, endogenously. The difficulties in de whether blood CO arises endogenously oi been the lack of knowledge of the vari govern CO uptake and loss from the uncertainty of the degree of exogenc sure to CO, and the lack of accurate ar CO analytical methods.In 1894, Grehant (1) monoxide nous and endogenous origin of the gas. In rethe blood cent years, the endogenous formation of CO has of the gas been studied by Sjdstrand and his associates in explained. Sweden (6, 7). the blood These investigators, however, have not measmany au-ured the actual rate at which CO is formed. The is formed instrument 1 used in their experiments to analyzẽ termining CO actually measures the temperature increase r not have during its catalytic combustion. In our hands, it is ables that relatively nonspecific for CO, and it seemed posbody, the sible that some of their findings might have been )us expo-produced by the presence of gases other than CO. id specific Their conclusion that CO is produced in normal man (7) depended on the demonstration of )rmal dog higher CO concentrations in expired than in in-)mbustible spired air. This, however, could be possible in the >), Leoper absence of endogenous CO formation if an unbloed (5) steady state existed between blood CO hemogloin human bin (COHb) and inspired CO concentration; this an exoge-could have occurred if their subjects had been exposed to higher CO concentrations in the environment as long as several hours before the experiments. We have developed an analytical method that appears to be specific for CO and can detect the addition of 0.3 ml of CO to the total adult C 0 2 human CO store by the analysis of a 2-ml blood A B SO R B E R sample (8). We have overcome some of the other criticisms by measuring the increase in blood COHb during extended periods of rebreathing in a closed system. METHODS

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“…The assumption that the CO stores in the blood are equilibrated with the "extravascular" CO stores is not rigorously correct under all conditions (i.e., transient states). The extravascular stores include CO bound to myoglobin and other compounds and make up a significant fraction (14) of the total body CO. It has been shown in experiments where CO was added to the blood that it may take as long as 60 minutes for blood CO to equilibrate with extravascular CO (12).…”

Section: Methodsmentioning

confidence: 99%

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Considerations of the physiological variables that determine the blood carboxyhemoglobin concentration in man.

Coburn¹,

Forster²,

Kane³

1965

J. Clin. Invest.

409

207

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Numerous publications have considered the effects of inspiring high concentrations of CO on the venous blood carboxyhemoglobin concentration [COHb] in man (14). It appears, however, that no previous study has considered the physiological variables that determine [COHb] under conditions where inspired air CO concentrations are in the normal range. It has become apparent in recent years that CO is endogenously produced in normal man as a by-product of hemoglobin catabolism (and probably other hemoproteins as well) and therefore that the body CO stores are influenced by endogenous as well as exogenous CO (5,6). The development of a method of measuring the rate of endogenous CO production (Vco) in man (6) has made it possible to study the relationship of Vco and other variables to [COHb]. This is of particular interest since the latter has been used as an index of hemolysis (7). The Vco has been shown to reflect quantitatively the rate of circulating erythrocyte hemoglobin destruction in normal subjects (8) and in patients with hemolytic anemia (9), and the accuracy of this index would depend on how closely [COHb] reflects Vco.In this paper we have developed equations that appear to describe the major physiological variables that determine blood [COHb] have applied these equations to data obtained from a) normal subjects, b) male volunteers who breathed 100% oxygen for extended periods of time, and c) patients with elevated rates of endogenous CO production. MethodsAir CO measurements. Samples of air taken from the "wards" of the Hospital of the University of Pennsylvania were analyzed for CO concentrations with an infrared CO meter. This instrument has an error (SD) of 4-0.00004% CO and requires a 200-ml sample. These samples were collected during the summer of 1964. Smoking is prohibited in the areas where these samples were collected. We also measured the CO concentrations in air samples taken from smoke-filled conference rooms, a small nonventilated room that we purposely filled with smoke by burning cigarettes, and a rural area well away from automobile combustion. Diurnal changes in blood [COHb] were measured in one subject and compared with the changes in percentage of CO in his environment. Blood [COHb] was determined by a method in which gas extracted from a 2-ml blood sample is measured in the infrared CO meter. This method has an error (SD) of 40.03% [COHb]( 10).Washout experiments. Three normal young male subjects breathed 100% oxygen for 4 to 8 hours. The subjects were seated, wore a noseclip, and breathed the oxygen through a mouthpiece using an open circuit equipped with two one-way valves that directed the expired gas into a 100-L bag in a box, which was in turn connected to a Tissot spirometer. The inspired oxygen contained less than 0.00001% CO. At hourly intervals minute ventilation was measured, expired gas samples were collected and analyzed for CO, and venous blood was drawn and analyzed for [COHb]. The rate of CO excretion (VEco) was calculated from the minute ventilation and CO concen...

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The Fate of Co in the Body During Recovery From Mild Carbon Monoxide Poisoning in Man

Cited by 52 publications

References 0 publications

The time course of the effects of carbon monoxide on visual thresholds

The time course of the effects of carbon monoxide on visual thresholds

Endogenous Carbon Monoxide Production in Man*

Considerations of the physiological variables that determine the blood carboxyhemoglobin concentration in man.

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