NOTE: Carboxy-
hemoglobin is also known as COHb; it is the molecule that forms when carbon monoxide bonds to hemoglobin, the molecule that carries oxygen in red blood cells.

MEDICAL LITERATURE SAMPLE
Compiled information courtesy CLMB Foundation.

1. CARBON MONOXIDE POISONING IN FETUSES AND CHILDREN

What you should know about carbon monoxide

"Infants, the elderly and sick persons are affected [by CO] first. Their ability to respond to adverse environments, coupled with their reduced lung capacity, increases the potential effects of CO exposure . . . In pregnancy the fetus is in much greater danger than the mother as the fetal levels of CO will continue to rise after the mother’s levels have peaked and begun to fall. In these situations, the mother may recover completely, but the fetus may be stillborn or born with serious brain damage."

American Gas Association, 1985 Operation Section Proceedings, Revised
Abstract and Health Effects Section 1988.

Carbon monoxide poisoning: From crib death to pickup trucks

"Of children born to women surviving significant CO poisoning, as many as 60 percent have neurological sequelae. Fetal death has been reported in cases of CO toxicity that are non-lethal for the mother. In these cases, fetal demise may be immediate or delayed."

Reisdorff, E., MD, FACEP, S. Shah, MD and R. Nelson, MD, FACEP, Emergency Medicine Reports, October 18, 1993, p. 184.

Carbon monoxide poisoning: An occult epidemic

"In Great Britain, carbon monoxide intoxication is the main cause of death by poisoning in children."

Sadovnikoff, N., MD, J. Varon, MD and G. Sternbach, MD. Postgraduate Medicine, 1992, p. 86.

Carbon monoxide intoxication

"The fetus is especially vulnerable to carbon monoxide intoxication for three reasons. First [a carboxyhemoglobin component in the mother] decreases the amount of oxygen released to the fetus. Second, hemoglobin the fetus has a higher affinity for carbon monoxide than hemoglobin in the adult. Finally, the elimination half-life of carboxyhemoglobin is longer in the fetus than in the adult."

Kales, S., MD, MPH, American Family Physician, November 1, 1993, p. 1101.

An addendum to the 1979 EPA Air Quality Criteria Document for carbon monoxide

"The 1979 Criteria Document directed attention toward identification of sensitive population groups at special risk of CO-induced health effects . . . These probable risk groups include: (1) fetuses and young infants; (2) the elderly, especially those with reduced cardiopulmonary functions . . . (3) other, younger individuals with overt severe cardiac damage or acutely severe respiratory diseases . . . (4) individuals with chronic bronchitis or emphysema; (5) individuals with symptoms (e.g., angina) indicative of chronic cardiovascular disease . . ."

EPA Document 600/8-83-033F, August, 1984, p. 19.

Neurotoxicity of prenatal carbon monoxide exposure

"These data are consistent with the hypothesis that early CO exposure damages developing neurons [perhaps causing] unscheduled cell death [which] is likely to have a profound and permanent effect; deficits in cell number which are unlikely to be made up later in life."

Fechter, L., Ph.D., Health Effects Institute, Research Report No. 12, 1987, p. 19.

Psychological sequelae to carbon monoxide intoxication in the child

"For younger children, the intoxication involves all the faculties simultaneously and determines overall intellectual deficiencies. As far as the influence of the intoxication on the instrumentalities is concerned, we observed that it makes pre-existing disorders [such as problems with visual-spatial perception, topographical memory and auditory memory] more severe, particularly between five and nine years."

Klees, M., M. Heremans and S. Dougan, The Science of the Total Environment, 1985, p. 173.

In-utero carbon monoxide poisoning and poisoning and multiple fetal abnormalities

"Carbon monoxide (CO) poisoning during pregnancy can lead to fetal fatalities and stillbirths . . . In the case we report, we strongly suspected an association between mild but chronic CO poisoning of the mother and major multiple malformations in the baby."

Hennequin, Y., D. Blum, E. Vamos, et al., The Lancet, January 23, 1993, p. 240.

The biological effects of carbon monoxide on the pregnant women, fetus, and newborn infant

"Studies on the effects of carbon monoxide n healthy young adults support the conclusion that blood carboxyhemoglobin levels as low as 4 to 5 percent result in invidious effects on vital functions. For instance, these levels cause a decrement in mental function, visual acuity, the performance of vigilance tasks, and aerobic metabolism under conditions of maximal oxygen uptake."

Lawrence D. Longo, MD, American Journal of Obstetrics Gynecology, September 1, 1977, p. 70.

2. LOW LEVEL CARBON MONOXIDE EXPOSURE

What you should know about carbon monoxide

". . . prolonged exposures . . . allow time for the CO to enter the tissues, allow disruption of intracellular metabolism, cause a rise in the products of lipid peroxidation. This is associated with cell damage . . . Severely poisoned individuals who have been subjected to exposures of long duration may experience severe delayed neurologic after-effects quite unlike those seen following simple hypoxia."

American Gas Association, 1985 Operation Section Proceedings, Revised Abstract and Health Effects Section 1988.

What you should know about carbon monoxide

". . . some patients have been dead on arrival with levels of 51 percent and some have remained in profound coma with levels of 20 percent or lower."

American Gas Association, 1985 Operation Section Proceedings, Revised Abstract and Health Effects Section 1988.

Carbon monoxide poisoning: Mechanisms, presentations, and controversies, in management

"Breathing as little as 0.1 percent CO for several minutes will result in CO occupying 60 percent of the available binding sites on hemoglobin (carboxyhemoglobin [COHb] level of 60 percent) . . . [COHb levels] over 50 to 60 percent [can cause] syncope, convulsions, and coma."

Olson, K., MD, Journal of Emergency Medicine, 1984, p. 234.

Carbon monoxide poisoning: From crib death to pickup trucks

". . . at a particular serum COHb level, low concentration exposures over a long period are more harmful than high concentration exposures over a brief interval."

Reisdorff, E., MD, FACEP, S. Shah, MD and R. Nelson, MD, FACEP, Emergency Medicine Reports, October 18, 1993, p. 181.

Carbon monoxide

"A number of early studies found that increments in COHb of less than five percent resulted in cardiovascular effects in normal volunteers, such as acute reduction in exercise tolerance, reductions in arterial and mixed venous oxygen tensions, and a reduction in the length of time to the onset of angina in men with stable angina pectoris."

American Conference of Governmental Industrial Hygienists, Threshold Limit Values and Biological Exposure Indices, p. 228.

Lesson of the week: Carbon monoxide poisoning in the home: Recognition and treatment

"The condition [CO poisoning] is under-diagnosed by general practitioners and accident and emergency departments because of the vague non-specific symptoms, especially in people with chronic exposure to low concentrations of carbon monoxide."

Crawford, R., D. Dampbell and J. Ross, British Medical Journal, October 27, 1990, p. 978.

Are arterial blood gases of value in treatment decisions for carbon monoxide poisoning?

"Traditionally, the carboxyhemoglobin level has been viewed as the major indicator of the severity of CO poisoning. However, there are problems with this concept in that patients are being found with low [carboxyhemoglobin levels] (<10 percent) and severe symptomatology (coma)."

Myers, R., MD and J. Britten, MD, Critical Care Medicine, February 1989 p. 139.

WARNING! Deadly carbon monoxide may be trapped in your home!

". . . even low levels of carbon monoxide can cause a significant displacement of oxygen n the hemoglobin. Thus, carbon monoxide prevents life-supporting oxygen from reaching the heart, brain and other body organs."

Block, L., PE, 714/498-9362.

Carbon monoxide poisoning

"In susceptible persons, stress and actual damage to the cardiovascular system have been said to be inducible at carboxyhemoglobin levels as low as 10 percent."

Marzella, L., MD, PhD, R. Myers, MD, American Practical Therapeutics, November 1986, p. 193.

Carbon monoxide poisoning in the home

"For someone with a known heart condition, inhalation of almost any CO can be fatal."

Pinckney, C., MD and E. Pinckney, Vector consumer Newsletter, November 8, 1988.

Carbon monoxide poisoning in the home

" . . . more than two percent [carboxyhemoglobin in the blood] can cause heart pains and mental impairment."

Pinckney, C., MD and E. Pinckney, Vector consumer Newsletter, November 8, 1988.

Carbon monoxide poisoning: An occult epidemic

"Carbon monoxide binds reversibly to hemoglobin with an affinity 200 to 230 times that of oxygen. Consequently, relatively minute concentrations of the gas in the environment can result in toxic concentrations in human blood."

Sadovnikoff, N., MD, J. Varon, MD and G. Sternbach, MD, Postgraduate Medicine, 1992, p. 86.

Acute effects of carbon monoxide exposure on individuals with coronary heart disease

"Thus, low levels of COHb produce health effects that can have significant consequences on the functional capacity of an individual performing activities of daily life."

Alfred, E., E. Bleecker, B. Chaitman, et. al., Health Effects Institute Report, p. 38.

Carbon monoxide levels in cardiac patients in an urban emergency department

"Clearly, levels as low as three percent COHb can be especially hazardous to cardiac patients."

Leikin, J., MD and S. Vogel, MD, American Journal of Emergency Medicine, March 1986, p. 127.

Smoke gets in your heart

"When the [carboxyhemoglobin] level is at two to four percent, which is common for many people in everyday situations, the symptoms are relatively subtle, though unpleasant. Impairment of thinking and fine coordination has been observed. New research shows that even at these levels, the heart is also affected."

No author listed, Harvard Medical School Health Letter, March 1990, p. 5.

Carbon monoxide and cardiovascular disease

"Impaired cerebral function has also been demonstrated during exposure to low concentrations of carbon monoxide."

Dwyer, Jr., E. MD and G. Turino, MD, New England Journal of Medicine, November 23, 1989, p. 1474.

Carbon monoxide poisoning

"The Hyperbaric Chamber facility of the Maryland Institute for Emergency Medical Services Systems (MIEMSS) has received comatose victims with CO levels of under five percent . . ."

Myers, R., MD, Journal of Emergency Medicine, 1984, p. 246.

Fetal death due to non-lethal maternal carbon monoxide poisoning

"In adults . . . inhalation of ambient gas which has a CO concentration of one percent can be fatal within ten minutes, depending on the victim’s activity and respiratory rate. Likewise, victims with underlying diseases such as anemia, heart dysfunction, or lung disease may succumb at much lower COHb concentrations."

Farrow, J., MD, G. Davis, MD, T. Roy, MD, et al., Journal of Forensic Sciences, July 19, 1989, p. 1450.

Carbon monoxide and cardiovascular disease

". . . evidence has been mounting that exposure to small amounts of carbon monoxide in the atmosphere has physiologic and clinical consequences, particularly for the cardiovascular system . . . Given the demonstration that low levels of carboxyhemoglobin induce ischemia in the myocardium and impair central nervous system functioning I patients with coronary and cerebrovascular disease, it is difficult to establish and safe level of carbon monoxide in ambient air. The safest level would be the lowest level achievable in the atmosphere."

Edward Dwyer, Jr., MD and Gerard Turino, MD, The New England Journal of Medicine, November 23, 1989, p. 1474.

Ambient air pollution and hospitalization for congestive heart failure among elderly people in seven large US cities

"This analysis shows a consistent association between increasing levels of ambient carbon monoxide and increasing hospital admissions for congestive heart failure among elderly people. This pattern was consistent across the seven large US cities included in the analysis. These associations persisted after adjustment for seasonal effects, temperature, and other gaseous pollutants, including nitrogen dioxide, sulfur dioxide, and ozone. None of these other pollutants showed consistent, significant associations with congestive heart failure admissions. These results suggest that ambient carbon monoxide levels or factors closely correlated with carbon monoxide levels participate or exacerbate congestive heart failure to the extent that hospitalization is required."

Robert D. Morris, MD, PhD, Elena N. Naumova, PhD, and Rajika L. Munasinghe, MBBS, MS, American Journal of Public Health, October 1995, p. 1364.

Occult carbon monoxide poisoning: Validation of a prediction model

"Previous studies have shown that among patients presenting to an urban emergency department during the winter with complaints of headache or dizziness, 3 to 5 percent will have unrecognized "occult" carbon monoxide poisoning, and will remain undetected unless carboxyhemoglobin values are obtained [3,4]. Our results among a cohort of patients who presented with headache or dizziness and who received carboxyhemoglobin testing support these observations."

Paul S. Heckerling, MD, Jerrold B. Leikin, MD, and Andrew Maturen, PhD, The American Journal of Medicine, February 1988, p. 254.

Carbon monoxide

"Cohen and colleagues (1969), studying 36 hospital admissions for myocardial infarction in the Los Angeles area, discovered a direct relationship between ambient carbon monoxide and myocardial infarction mortality rates, a finding that confirmed reports and opinions over the past 50 years. In a review of carbon monoxide and coronary artery disease. Goldsmith and Aronow (1975) concluded that the most vulnerable target organ for low level carbon monoxide exposure appears to be the heart."

Asher J. Finkel, Industrial Toxicology, Fourth Edition, p. 163.

3. CARBON MONOXIDE AS AN IMPORTANT HEALTH HAZARD

Subacute sequelae of carbon monoxide poisoning

"A wide range of neuropsychiatric abnormalities . . . and almost every known neurological syndrome can occur following carbon monoxide poisoning."

Myers, R., MD, S. Snyder, RN and T. Emhoff, MD, Annals of Emergency Medicine, December 1985, p. 1163.

Carboxyhemoglobin levels in patients with flu-like symptoms

"the literature is well supplied with reports of patients with subacute CO poisoning who were misdiagnosed as having influenza and sent home with disastrous consequences."

Dolan, M., MD, FRCP, T. Haltrom, MD, G. Barrows, MD, et. al. Annals of Emergency Medicine, July 1987, p. 785.

Carbon monoxide poisoning in the home

"Any [COHb] test value greater than ten percent warrants medical attention, even if no symptoms are evident."

Pinckney, C., MD and E. Pinckney, Vector Consumer Newsletter, November 8, 1988.

Carbon monoxide intoxication

"It is crucial to note that persons at the extremes of age and persons with underlying conditions (especially coronary artery disease, pulmonary disease and pregnancy) may have marked symptoms and may suffer serious complications at lower levels of carboxyhemoglobin."

Kales, S., MD, MPH, American Family Physician, November 1, 1993, p. 1102.

Carbon monoxide poisoning: A review: Epidemiology, pathophysiology, clinical finds, and treatment options including hyperbaric oxygen therapy

"It is a sobering testimonial to the complexity of this poison that studies on its intravascular as well as extravascular (cellular) mechanisms have been pursued for more than 100 years."

Thom, S., MD, PhD and L. Keim, MD, Clinical Toxicology, 1989, p. 150.

Neurotoxicity of prenatal carbon monoxide exposure

"Carbon monoxide may be thought of as both a prototypical hypoxic agent and a significant public health hazard in its own right. Carbon monoxide . . . accounts for large numbers of deaths and significant morbidity in human populations."

Fechter, L., PhD, Health Effect Institute, Research Report No. 12, 1987, p. 3.

A guide to commonly encountered toxics (Part two)

"Carbon monoxide is responsible for a larger number of severe chemical poisonings than any other single agent . . ."

Harte, J., C. Holdren, R. Schneider and C. Shirley, Toxics A to Z: A Guide to Everyday Pollution Hazards, University of California Press, 1991, p. 257.

Clinical and laboratory observations; Carboxyhemoglobin levels in children with nonspecific flu-like symptoms

"Our findings demonstrate that no specific symptom complex could help in distinguishing carbon monoxide poisoning from a presumed viral illness. Indeed, in many of our patients elevated carboxyhemoglobin levels would not have suspected on the basis of routine history or physical findings alone."

Baker, D., MD, F. Henritig and S. Ludwig, Journal of Pediatrics, September 1988, p. 503.

Clinical and laboratory observations: Carboxyhemoglobin levels in children with non-specific flu-like symptoms

"We contend that the crucial importance of accurate diagnosis in this group [children with two to five percent carboxyhemoglobin levels] is not the opportunity provided for prompt treatment to reduce carboxyhemoglobin levels so much as the prompt recognition of a hazardous environment. These same children [and their families] are potentially at risk for serious and possibly life-threatening injury if exposure were to continue."

Baker, D., MD, F. Henritig and S. Ludwig, Journal of Pediatrics, September 1988, p. 504.

Carbon monoxide poisoning: An occult epidemic

". . . it appears that outcome [of patients with carbon monoxide poisoning] is fatal in about 30 percent of cases of severe poisoning . . . One third of carbon monoxide poisoning victims may have subtle but lasting memory deficit or personality changes."

Sadovnikoff, N., MD, J. Varon, MD and G. Sternbach, MD, Postgraduate Medicine Reports, October 18, 1992, p. 94.

Unintentional carbon monoxide-related deaths in the United States, 1979 through 1988

"Carbon monoxide is produced in lethal amounts by every automobile and fuel-burning appliance. Everyone in modern society is at risk."

Cobb, N., MD and R. Etzel, MD, PhD, Journal of the American Medical Association, August 7, 1991, p. 559.

Subacute carbon monoxide poisoning: Another great imitator

"Since the organ most sensitive to an oxygen deficit is the brain, it is not surprising that a myriad of CNS [central nervous system] complications can develop and may be delayed up to 300 days after exposure."

Grace, T., MD and F. Platt, MD, Journal of the American Medical Association, October 9, 1981, p. 1700.

Morbidity for acute carbon monoxide poisoning at three-year follow-up

"In some cases [of acute CO poisoning] defects such as Parkinson's disease, intellectual change, and organic personality change had become evident only after the patient’s discharge from hospital, emphasizing the importance of following up every case for an interval which allows for the delayed onset of sequelae."

Smith, J. and S. Brandon, British Medical Journal, February 10, 1973, p. 320.

Carbon monoxide poisoning at an indoor ice arena and bingo hall - Seattle, 1996

"Because early symptoms of CO exposure are nonspecific (e.g., headache, dizziness, weakness, and confusion), CO poisoning may be misdiagnosed as acute, self-limited illnesses (e.g., upper respiratory tract infection and food poisoning).

JAMA, May 15, 1996, p. 1468.

Carbon monoxide poisoning: Mechanisms, presentation, an controversies in management

"Many victims of CO poisoning die or suffer permanent, severe neurologic injury despite treatment. In addition, as many as 40 to 50 percent of those who recover consciousness and survive may experience varying degrees of more subtle but still disabling neuropsychiatric sequelae such as memory impairment or personality deterioration."

Olson, K., MD, Journal of Emergency Medicine, 1984, p. 233.

Carbon monoxide poisoning: Mechanisms, presentation, and controversies in management

". . . some patients remain comatose even after their COHb levels have returned to near zero."

Olson, K., MD, Journal of Emergency Medicine, 1984, p. 235.

Value of hyperbaric oxygen in suspected carbon monoxide poisoning

"After a long delay, CO may not be detectable in the blood. Consequently, patients can remain in a depressed clinical state even after the apparent elimination of CO from the body."

Myers, R., MD, S. Snyder, RN, S. Linberg, PhD, and A. Cowley, MD, Journal of the American Medical Association, November 17, 1981, p. 2478.

Cerebral blood flow and glucose metabolism measurements in a patient surviving one year after carbon monoxide intoxication.

"After exposure to CO, various levels of impaired consciousness and subsequent slow responsiveness to stimuli are characteristics of CO encephalopathy. Many patients suffer from longstanding neuropsychiatric deficits and occasionally relapse to severe mental deterioration and fatal coma."

Eku Shimosegawa, Jun Hatazawa, Ken Nagata, Toshio Okudera, Atsushi Inugami, Toshihide Ogawa, Hideaki Fujita, Hiroshi Itoh, Iwao Kanno, and Kazuo Uemura, The Journal of Nuclear Medicine, September 1992, p. 1697.

Compiled information courtesy CLMB Foundation.