Carbon monoxide poisoning mortality in the United States from 2015-2021.

INTRODUCTION: Most carbon monoxide poisoning is preventable. Tracking of longitudinal trends in carbon monoxide-related mortality is needed to guide public health efforts. This study sought to describe mortality in the United States from carbon monoxide poisoning, examine the epidemiology of unintentional ("accidental") and intentional exposures, and identify trends in both. METHODS: The Centers for Disease Control and Prevention's Wonder databases were utilized to extract online data from National Center for Health Statistics files containing mortality data in the United States from 2015-2021. Extracted were deaths, crude death rates, intent of exposure, and demographics of persons dying from carbon monoxide poisoning, excluding cases related to fires. Also extracted was the number of suicidal deaths of all types. Carbon monoxide deaths related to consumer products were obtained from the Consumer Product Safety Commission. Information on state legislation mandating residential carbon monoxide alarms was obtained from online resources. RESULTS: Total carbon monoxide deaths decreased from 1,253 in 2015 to 1,067 in 2021. An increase in accidental poisoning deaths was offset by a larger decrease in intentional deaths, despite an increase in suicides of all types in the country. For the first time in the United States, accidental carbon monoxide deaths (543) outnumbered intentional deaths (524) in 2021. The increase in accidental deaths is consistent with those recently reported from carbon monoxide-emitting consumer products by the Consumer Product Safety Commission. Furthermore, even though over one-half of accidental deaths occurred at home, no evidence of a protective effect of state laws requiring residential carbon monoxide alarms was seen. CONCLUSIONS: Accidental carbon monoxide poisoning deaths increased from 2015-2021 for the first time in four decades. Exploration of the possibility they are due to consumer products warrants attention and prevention efforts. We were unable to demonstrate the preventive effect of residential carbon monoxide alarm legislation.

Comparison of four low-level carbon monoxide alarms suitable for home use or when traveling.

Introduction: Interest in carbon monoxide (CO) alarms that are more sensitive than is required for standard residential CO alarms is growing, as reflected by increased marketing of "low-level" alarms capable of measuring CO levels as low as 10 PPM. At the same time, publicity surrounding CO poisoning events among travelers in lodging facilities has stimulated interest in travel CO alarms. We sought to evaluate four low-level alarms that could be used in the home and especially when traveling. Materials/Methods: Two each of four brands of low-level alarms (CO Experts, Forensics, Kidde, and Sensorcon) were acquired by retail purchase and tested. The eight alarms were simultaneously exposed in an environment with a slowly increasing level of CO from indoor burning of charcoal briquets. CO levels displayed on the alarms were recorded once per minute. Activation of preset alerts on the alarms were noted. Finally, alarms were compared for ease of use and features available.. Results: All brands of alarms measured CO similarly over the range from 10-120 PPM. All alarms performed as claimed by their manufacturers, both regarding range of CO reported and preset alert activation. Each alerted at CO levels below that required by the Underwriters Laboratories 2034 Standard. Summary/Conclusion: Since all low-level CO alarms tested measured CO similarly, consumers seeking a low-level CO alarm for use while traveling should base their decision on features desired and price. There are definite differences between the alarms tested, in terms of features, expected durability, ease of operation and price.

Preventing carbon monoxide poisoning in the Hudson River Tunnel in 1921: recounting history.

The New York Bridge and Tunnel Commission began planning for a tunnel beneath the lower Hudson river to connect Manhattan to New Jersey in 1919. At 8,300 feet, it would be the longest tunnel for passenger vehicles in the world. A team of engineers and physiologists at the Yale University Bureau of Mines Experiment Station was tasked with calculating the ventilation requirements that would provide safety from exposure to automobile exhaust carbon monoxide (CO) while balancing the cost of providing ventilation. As the level of ambient CO which was comfortably tolerated was not precisely defined, they performed human exposures breathing from 100 to 1,000 ppm CO, first on themselves and subsequently on Yale medical students. Their findings continue to provide a basis for carbon monoxide alarm requirements a century later.

Arterial gas embolism breathing compressed air in 1.2 metres of water.

Arterial gas embolism (AGE) may result when diving while breathing compressed gas and ascending rapidly or with a closed glottis. Pulmonary over-pressurisation can result in lung stretch injury with entry of bubbles into the pulmonary venous circulation and subsequently the systemic arterial circulation. We present the case of an individual who suffered AGE while breathing compressed air at 1.2 metres' fresh water (mfw) in a swimming pool and discuss the factors determining the depth at which this form of injury may occur. This case serves to underscore the fact that risk of AGE exists at shallow depths.

Carbon monoxide poisoning while scuba diving: a rare event?

Contamination of breathing gas is a risk for all divers. Some hydrocarbon contaminants will be sensed by the diver and the dive profile aborted. On the contrary, carbon monoxide may not be recognized by the diver and catastrophic consequences can result. Reported here is the fatal case of carbon monoxide poisoning while scuba diving, an event that has rarely been reported in the medical literature. A detailed review of other published cases of CO poisoning while scuba diving is included, attempting to identify causes in common and propose methods of prevention.

Racial and ethnic trends in unintentional carbon monoxide poisoning deaths.

OBJECTIVE: Government programs have attempted to impact a recognized elevated risk for carbon monoxide (CO) poisoning among minority racial and ethnic groups. This study sought to describe U.S. mortality due to unintentional, non-fire-related CO poisoning, examining the distribution and trends by race and ethnicity. METHODS: CDC Wonder was used to extract and analyze data on all U.S. resident deaths from unintentional CO poisoning from 2000-2017, categorizing them by year, race, ethnic origin and gender. RESULTS: The absolute number of unintentional CO deaths decreased from about 450 to 380 per year during the period studied, a number near totally accounted for by the decrease in deaths occurring among non-Hispanic/Latino whites. The number of deaths among the remainder of the population did not significantly change. However, greater growth in minority populations resulted in a similar decline in the mortality rate between non-Hispanic/Latino whites and the combined minority population. The decline in combined minority death rate resulted from a decrease in the Hispanic/Latino white rate. Death rate did not decline in the black or African American population. CONCLUSIONS: All minority groups continue to display a disproportionate number of unintentional non-fire-related CO poisoning deaths compared to non-Hispanic/Latino whites. The decrease in U.S. deaths from unintentional non-fire-related carbon monoxide poisoning from 2000-2017 is accounted for by a decrease in non-Hispanic/Latino white deaths. While numbers of such deaths among minority groups have not changed since 2000, increases in the size of minority populations have resulted in a declining crude death rate for Hispanic/Latino whites.

Carbon monoxide poisonings in hotels and motels: The problem silently continues.

Carbon monoxide poisoning remains common in the United States. One component of effective prevention involves identification of scenarios in which poisoning occurs to guide development of appropriate interventions. This study was conducted to determine the significance of the problem of carbon monoxide poisoning occurring in US hotels, motels and resorts. This is a population-based case series of guests staying at US hotels, motels, and resorts from 2005 to 2018. Details of incidents and individuals poisoned with carbon monoxide were collected from online searches and professional experience of the authors. Data extracted included number of incidents and individuals poisoned, age of those poisoned, outcomes, source of carbon monoxide, and lodging type. From January 1, 2005 to December 31, 2018, 905 guests were poisoned in 115 identified incidents, including 22 fatalities. Children represented 16% of those poisoned and 27% of fatalities. Type of lodgings were hotels, motels, and resorts of all classes and located in a majority of states. Most poisonings were caused by natural gas fueled appliances and could likely have been prevented by an in-room carbon monoxide alarm. To reduce morbidity and mortality from unintentional CO poisoning in lodging facilities, government should mandate installation of in-room CO alarms, similar to the current requirement for smoke alarms.

Carboxyhemoglobin: a primer for clinicians.

One of carbon monoxide's several mechanisms of toxicity is binding with circulating hemoglobin to form carboxyhemoglobin, resulting in a functional anemia. While patients with carbon monoxide poisoning are often said to be "cherry-red," such discoloration is rarely seen. Carboxyhemoglobin levels cannot be measured with conventional pulse oximetry, can be approximated with pulse CO-oximetry, and are most accurately measured with a laboratory CO-oximeter. Carboxyhemoglobin levels are quite stable and can be accurately measured on a transported blood sample. For clinical purposes, arterial and venous carboxyhemoglobin levels can be considered to be equivalent. Carboxyhemoglobin levels are typically lower than 2% in non-smokers and lower than 5% in smokers. A level over 9% is almost always due to exogenous carbon monoxide exposure, even among smokers. Conversely, a low level does not exclude significant exposure under certain circumstances. As carboxyhemoglobin levels of poisoned patients do not correlate with symptoms or outcome, their greatest utility is a marker of exposure.

Cost effectiveness of residential carbon monoxide alarms.

BACKGROUND: While residential carbon monoxide (CO) alarms are now required in a majority of states, the cost effectiveness of the devices is unknown. This analysis was performed to determine the degree of prevention efficacy necessary from home carbon monoxide alarms for their expense to be cost-effective. METHODS: Data regarding numbers of individuals affected in the United States annually from accidental, non-fire, residential non-fatal and fatal carbon monoxide poisoning were obtained from published literature. Federal governmental estimates of societal costs associated with medical care, lost wages and earnings, value of pain and suffering, and value of a statistical life were applied. The cost of uniform residential carbon monoxide alarm installation was compared to those societal costs in order to calculate what degree of efficiency makes alarms cost-effective. RESULTS: Societal costs for accidental, non-fire, residential CO poisoning are approximately $3.47 billion annually. With an estimated cost of $348 million annually for alarms, prevention of greater than 10% of residential CO poisoning costs must be achieved in order for alarms to be cost-effective. CONCLUSIONS: While the true effectiveness of residential carbon monoxide alarms has yet to be determined, current state legislation requiring residential installation of CO alarms is probably cost-effective. .

Comparison of normobaric vs. hyperbaric oxygen in the relief of carbon monoxide headache pain.

BACKGROUND: Headache is the most common symptom in carbon monoxide (CO) poisoning. While the mechanism of CO-induced headache is not well defined, it is felt that cerebral vasodilation plays a role. Clinical experience has demonstrated oxygen breathing is effective in resolving CO headache. However, the effectiveness of normobaric oxygen has never been compared to hyperbaric oxygen in this regard. METHODS: A 2016 paper by Ocak, et al. reported the response of CO headache pain severity to four hours of normobaric oxygen breathing in 82 patients using a 0-10 analog scale. The demographics, carboxyhemoglobin levels and response to therapy from that report were compared to data obtained by Hampson, et al. in an earlier study, but never published, using the same pain assessment method in 73 patients with CO headache and treated with hyperbaric oxygen. RESULTS: Comparing the normobaric and hyperbaric groups, neither average age nor presenting carboxyhemoglobin levels were significantly different. Baseline pain intensity scores were 6.5 ± 3.1 vs. 6.2 ± 2.6 (p=0.444) and post-treatment scores 1.5 ± 2.6 vs. 1.0 ± 1.5 (p=0.184) respectively on a 0-10 scale. CONCLUSIONS: In these two well-matched populations of patients with CO-induced headache pain, degree of resolution was not significantly different between normobaric and hyperbaric oxygen treatment.

Garage carbon monoxide levels from sources commonly used in intentional poisoning.

BACKGROUND: The incidence of intentional carbon monoxide (CO) poisoning is believed to have declined due to strict federal CO emissions standards for motor vehicles and the uniform application of catalytic converters (CC). We sought to compare ambient CO levels produced by automobiles with and without catalytic converters in a residential garage, as well as from other CO sources commonly used for intentional poisoning. METHODS: CO levels were measured inside a freestanding 73 m3 one-car garage. CO sources included a 1971 automobile without CC, 2003 automobile with CC, charcoal grill, electrical generator, lawn mower and leaf blower. RESULTS: After 20 minutes of operation, the CO level in the garage was 253 PPM for the car without a catalytic converter and 30 PPM for the car equipped withone. CO levels after operating or burning the other sources were: charcoal 200 PPM; generator >999 PPM; lawn mower 198 PPM; and leaf blower 580 PPM. CONCLUSIONS: While emissions controls on automobiles have reduced intentional CO poisonings, alternate sources may produce CO at levels of the same magnitude as vehicles manufactured prior to the use of catalytic converters. Those involved in the care of potentially suicidal individuals should be aware of this.