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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.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..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.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.

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.

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.

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.

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.

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 carboxy-hemoglobin 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.

Carbon monoxide (CO) poisoning is responsible for significant morbidity and mortality in the US. In response, a majority of states have passed legislation in recent years requiring the installation of residential CO alarms. There is, however, no published information evaluating compliance with such laws. Employees of a Seattle medical center were surveyed in 2008 regarding home use of CO and smoke alarms. Washington State enacted legislation requiring residential CO alarms by all residences by January 1, 2013. The survey was repeated in mid-2016 to evaluate compliance. In 2016, a total of 354 employees completed the survey and their responses were compared to an equal number of 2008 survey respondents matched by home ownership and ZIP code. Residential CO alarm use rose from 37% to 78% (p, Highlights • Washington State has required residential carbon monoxide alarms since 2013. • A survey on use of home CO alarms was conducted in 2008 and 2016. • Residential CO alarm use increased from 41% to 78% overall. • For the 20% of renters without alarms, most said their landlord didn't provide one. • Use of home CO alarms increased significantly but further improvement is possible.

The American College of Emergency Physicians (ACEP) recently published its official policy on the evaluation and management of patients with acute carbon monoxide (CO) poisoning [1], an update of the policy previously published in 2008. Three questions regarding CO poisoning were posed to a 30-person ACEP subcommittee, which employed a comprehensive literature review to attempt to draw conclusions. While this is a major step forward, we feel that their conclusions warrant comment.

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 free-standing 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 with one. 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.

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.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.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.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 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.

Background Although levodopa is the most effective oral PD therapy, many patients experience motor fluctuations, including sudden loss of dose effect and delayed benefit. CVT-301 is a levodopa inhalation powder with the potential for rapid onset of action. The objective of this study was to evaluate CVT-301 self-administered by PD patients to relieve OFF episodes. Methods PD patients with ≥2 hours per day of OFF time despite oral levodopa ≥4 times per day were randomized to CVT-301 or placebo for 4 weeks, to be used up to 3 times per day for OFF episodes. After 2 weeks, the study-drug dose was escalated from 35 to 50 mg. The primary end point was mean change in UPDRS Part III score from a predose OFF state to the average of postdose scores obtained at 10, 20, 30, and 60 minutes, as assessed in-clinic at the end of week 4. Home diaries were recorded. Results Eighty-six patients used the study drug at an average frequency of 2.1 times per day for CVT-301 and for placebo. At 4 weeks, least-squares mean change in UPDRS Part III score favored CVT-301 by 7.0 points (P < 0.001). A treatment effect was evident at 10 minutes. At 4 weeks, least-squares mean OFF-time change from baseline favored CVT-301 by 0.9 hours per day (P = 0.045). The most frequently reported adverse events in the CVT-301 group were dizziness, cough, and nausea, each in 7% (3 of 43 patients). Conclusions CVT-301 self-administered during OFF episodes provided rapid improvement of motor function, and daily OFF time was significantly reduced at the higher dose. CVT-301 was generally safe and well-tolerated. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

Background Portable electrical generators have been responsible for over 800 accidental carbon monoxide (CO) poisoning deaths in the United States from 1999–2012. Objectives Because mortality figures are typically the only data reported with regard to the adverse effects of generators, we describe a nonfatal segment of the poisoned population to further emphasize the significance of the problem. Methods Unidentifiable information about patients treated in the United States with hyperbaric oxygen for acute CO poisoning was prospectively reported by participating centers. Those patients poisoned by portable generators were selected for analysis. Results Of 1604 patients reported from August 1, 2008 to July 31, 2011, there were 264 accidentally poisoned by portable generators. Exposures occurred in 151 incidents in 33 states. In 99 incidents, poisoning occurred in a residence. Average patient age was 37 ± 20 years (range 1 to 90+ years). Of those poisoned, 146 (55%) were non-Hispanic white, 57 (22%) were black, 52 (20%) were Hispanic white, 4 (2%) were Asian, and 4 (2%) were Native American. English was spoken by 96%. The most common symptoms included headache (62%), dizziness (52%), and loss of consciousness (50%). Blood carboxyhemoglobin levels averaged 22.7 ± 9.0% (range 2.3–48.3%). Thirty-six patients demonstrated evidence of cardiac ischemia. Conclusions Acute, severe CO poisoning from portable electric generators is common in the United States, likely affecting an estimated 4000 individuals annually, occurring predominantly in residential settings, and affecting English language-speaking individuals.

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.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.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.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. .

Carbon monoxide (CO) poisoning accounts for hundreds of deaths and thousands of emergency department visits in the United States annually. Development of initiatives to reduce CO mortality through poisoning prevention requires a comprehensive understanding of the condition.To describe U.S. mortality from 1999 to 2014 due to CO poisoning from all sources except fires, to examine the epidemiology of accidental and intentional exposures, and to identify trends.The CDC WONDER database was used to extract and analyze data from the CDC's Multiple Cause of Death 1999-2014 file. The file contains mortality data derived from all death certificates filed in the United States.Information on deaths, crude death rate, age-adjusted death rate, intent of exposure, and characteristics of exposures from CO poisoning was extracted. Total deaths by CO poisoning decreased from 1,967 in 1999 to 1,319 in 2014 (P 0.001). Crude and adjusted death rates fell accordingly. Accidental poisoning accounted for 13% fewer deaths per year in 2014 than in 1999 (P 0.001). The number of intentional deaths by CO poisoning decreased by 47% over the same period (P 0.001). The rate of decline in combined adjusted death rates from 1999 to 2014 in the 19 states that required residential CO alarms by 2010 was not different from that for the 31 states that did not require residential alarms (P = 0.982).Numbers of deaths and death rates, both accidental and intentional, due to CO poisoning significantly declined in the United States from 1999 to 2014. Continued public education about CO toxicity should be emphasized. Additional study is needed to demonstrate the efficacy of residential CO alarms.

Spirometry patterns suggesting restrictive and obstructive pulmonary dysfunction have been reported in Parkinson's disease (PD). However, the patterns' precise relation to PD pathophysiology remains unclear. Purpose/Aim. To assess ON- versus OFF-state pulmonary function, the quality of its spirometric evaluation, and the quality of longitudinal spirometric findings in a large sample of PD patients with motor fluctuations.During a placebo-controlled trial of an inhaled levodopa formulation, CVT-301, in PD patients with ≥2 h/d of OFF time, spirometry was performed by American Thoracic Society (ATS) guidelines at screening and throughout the 4-week treatment period.Among 86 patients, mean motor impairment during an OFF state at screening was moderately severe. However, mean spirometry results at screening were within normal ranges, and in a mixed model for repeated measures (MMRM), the results at screening were not dependent on motor state (ON vs. OFF). In the placebo group (n = 43), 76% of ON-state and 81% of OFF-state examinations throughout the study met ATS quality metrics, and in an MMRM analysis, mean findings at these patients' arrivals for treatment-period visits showed no significant 4-week change. Across all 86 patients, flow-volume curves prior to any study-drug administration showed only a 3% incidence of "sawtooth" morphology.In PD patients with motor fluctuations, longitudinal spirometry of acceptable quality was generally obtained. Although mean findings were normal, about a quarter of spirograms did not meet ATS quality criteria. Spirogram morphology may be less indicative of various forms of respiratory dysfunction than has previously been reported in PD.

Background Cancer is a significant global health problem. Radiotherapy is a treatment for many cancers and about 50% of people having radiotherapy will be long-term survivors. Some will experience late radiation tissue injury (LRTI) developing months or years later. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based upon the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of problems following surgery. Objectives To assess the benefits and harms of HBOT for treating or preventing LRTI. Search methods We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 11), MEDLINE, EMBASE, DORCTIHM and reference lists of articles in December 2015. We also searched for ongoing trials at clinicaltrials.gov. Selection criteria Randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing. Data collection and analysis Three review authors independently evaluated the quality of the relevant trials using the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions and extracted the data from the included trials. Main results Fourteen trials contributed to this review (753 participants). There was some moderate quality evidence that HBOT was more likely to achieve mucosal coverage with osteoradionecrosis (ORN) (risk ratio (RR) 1.3; 95% confidence interval (CI) 1.1 to 1.6, P value = 0.003, number needed to treat for an additional beneficial outcome (NNTB) 5; 246 participants, 3 studies). There was also moderate quality evidence of a significantly improved chance of wound breakdown without HBOT following operative treatment for ORN (RR 4.2; 95% CI 1.1 to 16.8, P value = 0.04, NNTB 4; 264 participants, 2 studies). From single studies there was a significantly increased chance of improvement or cure following HBOT for radiation proctitis (RR 1.72; 95% CI 1.0 to 2.9, P value = 0.04, NNTB 5), and following both surgical flaps (RR 8.7; 95% CI 2.7 to 27.5, P value = 0.0002, NNTB 4) and hemimandibulectomy (RR 1.4; 95% CI 1.1 to 1.8, P value = 0.001, NNTB 5). There was also a significantly improved probability of healing irradiated tooth sockets following dental extraction (RR 1.4; 95% CI 1.1 to 1.7, P value = 0.009, NNTB 4). There was no evidence of benefit in clinical outcomes with established radiation injury to neural tissue, and no randomised data reported on the use of HBOT to treat other manifestations of LRTI. These trials did not report adverse events. Authors' conclusions These small trials suggest that for people with LRTI affecting tissues of the head, neck, anus and rectum, HBOT is associated with improved outcome. HBOT also appears to reduce the chance of ORN following tooth extraction in an irradiated field. There was no such evidence of any important clinical effect on neurological tissues. The application of HBOT to selected participants and tissues may be justified. Further research is required to establish the optimum participant selection and timing of any therapy. An economic evaluation should be undertaken.

Carbon monoxide (CO) poisoning is common in the United States, accounting for hundreds of deaths and thousands of emergency department visits annually. It is believed that most accidental CO poisoning is preventable through public education, warning labels on consumer products, and uniform use of residential CO alarms. However, cost effectiveness of these prevention strategies has not been demonstrated in the United States to date. It was the objective of this study to estimate societal cost of accidental CO poisoning and evaluate the cost-effectiveness of universal installation of residential CO alarms. Published studies and data from the English language literature were used in to estimate direct hospital costs and lost earnings resulting from accidental CO poisoning. The study was performed in the US in 2015. Approximately 6600 individuals are estimated to sustain long-term cognitive sequela annually, with total loss in earnings of approximately $925 million, 334 individuals die from accidental, non-fire related CO poisoning with an average loss of 26 years of productivity accounting for $355 million, and 2800 are hospitalized with acute medical care costs of $33 million. Available data indicate that accidental CO poisoning in the US conservatively costs society over $1.3 billion, resulting from direct hospital costs and lost earnings. Further, it demonstrates a positive cost-benefit ratio for the uniform use of residential CO alarms., Highlights • CO poisoning results in acute hospitalization costs and lost wages due to disability and death. • Accidental, non-fire related poisoning accounts for over $1.3 billion annually in societal costs. • This estimate of costs is a conservative figure and the true costs are probably much higher. • Residential carbon monoxide alarms are cost-effective in prevention of accidental poisoning.

Background Numerous states and localities have recently passed legislation mandating the installation and use of residential carbon monoxide (CO) detectors/alarms. Interestingly, there seems to be confusion about the optimal placement, if any, of CO alarms inside the home. Objectives It was the goal of this study to demonstrate the behavior of CO in air and to help provide a data-based recommendation for CO alarm placement. Methods CO was calculated to be slightly lighter than air. An 8-foot-tall airtight Plexiglas chamber was constructed and CO monitors placed within at the top, middle, and bottom. CO test gas (15 L, 3000 parts per million) was infused at each of the three heights in different trials and CO levels measured over time. Results Contrary to a significant amount of public opinion, CO did not layer on the floor, float at the middle of the chamber, or rise to the top. In each case, the levels of CO equalized throughout the test chamber. It took longer to equalize when CO was infused at the top of the chamber than the bottom, but levels always became identical with time. Conclusions As would have been predicted by the Second Law of Thermodynamics, CO infused anywhere within the chamber diffused until it was of equal concentration throughout. Mixing would be even faster in the home environment, with drafts due to motion or temperature. It would be reasonable to place a residential CO alarm at any height within the room.

BACKGROUND: Although hyperbaric oxygen is used to treat chronic radiation tissue injury, clinical evidence supporting its efficacy has been limited to date. The authors report prospectively collected patient outcomes from a single center's large experience using hyperbaric oxygen to treat chronic radiation injury. METHODS: Since 2002, patient outcomes at the conclusion of a course of hyperbaric oxygen treatment for chronic radiation tissue injury at Virginia Mason Medical Center in Seattle have been graded by a board-certified hyperbaric physician and prospectively recorded. From 2002 to 2010, a total of 525 patients received treatment for 1 of 6 forms of radionecrosis analyzed. After excluding 114 patients for incomplete records or treatment courses or for previous receipt of hyperbaric oxygen therapy, records of 411 patients were retrospectively reviewed in 2010, and outcomes were regraded by a second board-certified physician. A positive clinical response was defined as an outcome graded as either “resolved” (90%-100% improved) or “significantly improved” (50%-89% improved). RESULTS: A positive outcome from hyperbaric treatment occurred in 94% of patients with osteoradionecrosis of the jaw (n = 43), 76% of patients with cutaneous radionecrosis that caused open wounds (n = 58), 82% of patients with laryngeal radionecrosis (n = 27), 89% of patients with radiation cystitis (n = 44), 63% of patients with gastrointestinal radionecrosis (n = 73), and 100% of patients who were treated in conjunction with oral surgery in a previously irradiated jaw (n = 166). CONCLUSIONS: The outcomes of 411 patients collected prospectively over 8 years strongly supported the efficacy of hyperbaric oxygen treatment for the 6 conditions evaluated. The response rates previously reported in numerous small series were supported by the responses achieved in this large, single-center experience. Cancer 2012. © 2011 American Cancer Society.

Recent data suggest that patients surviving acute carbon monoxide (CO) poisoning (COP) may have increased risk for long-term mortality. The objective of this study was to analyze long-term mortality of a large population of CO-poisoned patients treated at one medical center over three decades.Retrospective cohort study of patients treated with hyperbaric oxygen and surviving the acute poisoning episode. Long-term mortality was compared to a standard population. Comparison of mortality within the cohort by clinical indicators of poisoning severity was assessed using Cox proportional hazards regression analysis.Regional referral center for hyperbaric treatment of COP.One thousand seventy-three patients agedor=18 years treated from 1978 to 2005.All patients received hyperbaric oxygen treatment.During 11,741 person-years of follow-up, 162 subjects died. The expected number of deaths was 87 (standardized mortality ratio [SMR]), 1.9; 95% confidence interval [CI], 1.6-2.2). Most of the excess mortality was in the group treated initially for intentional COP (58 excess deaths; SMR, 3.7; 95% CI, 2.9-4.6) vs. those treated for accidental COP (17 excess deaths; SMR, 1.3; 95% CI, 1.01-1.6). For the entire cohort, the major causes of death with significantly raised mortality were mental and psychiatric disorders, injuries, and violence. More specific causes of death with significantly raised mortality were alcoholism, motor vehicle accidents with pedestrians, motor vehicle accidents of unspecified type, accidental poisonings, and intentional self-harm. Within cohort comparisons showed that no difference in survival was observed by measure of CO poisoning severity, after controlling for age at poisoning, sex, race, and intent of CO poisoning.Adult survivors of acute CO poisoning treated with hyperbaric oxygen were at increased risk for long-term mortality. Such patients should be followed closely after discharge with consideration given to psychiatric and/or neurocognitive evaluation, as appropriate.

Carbon monoxide (CO) poisoning is common in the United States, accounting for approximately 2,700 deaths annually. Few publications have described the mortality rate of CO-poisoned patients who survive to reach a hospital and die despite maximal medical care. Further, while risk factors for cognitive sequelae in survivors of CO poisoning have become clearer recently, factors associated with death are less well defined. This study was conducted to 1) determine the short-term mortality risk for patients treated with hyperbaric oxygen for CO poisoning, and 2) determine whether any factors related to the poisoning episode are predictive of mortality.A departmental database and medical records of 1,505 consecutive patients treated with hyperbaric oxygen at a single institution from 1978 to 2005 were reviewed.Demographic and clinical data were extracted for analysis. Mortality data, including cause of death, were obtained through a search of the National Death Index of the National Center for Health Statistics.A total of 38 patients experienced short-term mortality from their episode of CO poisoning, yielding a death rate of 2.6% in medically treated patients. Characteristics significantly associated with mortality included fire as a source of CO, loss of consciousness, carboxyhemoglobin level, arterial pH, and presence of endotracheal intubation during hyperbaric treatment.The mortality rate for medically treated CO-poisoned patients in this series was 2.6%, similar to the limited combined experience previously reported in the literature. Factors most strongly associated with mortality were severe metabolic acidosis and need for endotracheal intubation.

Background Elevated blood carboxyhemoglobin (COHb) levels are used to confirm a clinical diagnosis of exposure to carbon monoxide (CO) and, in some instances, assess severity of poisoning. However, many hospital laboratories cannot measure COHb because they do not have CO-oximeters. In such instances, blood samples are often sent to outside laboratories or with a transported patient for measurement at the receiving hospital. This study was conducted to assess the stability of COHb in stored and mailed blood samples anticoagulated with heparin. Methods Adult human blood was drawn into standard sample tubes anticoagulated with sodium heparin. Carbon monoxide gas was infused to raise the COHb level to 25% to 35%. Samples were then refrigerated or stored at room temperature, and serial COHb determinations were performed for 28 days. Additional samples were measured after being mailed locally or across the United States and back. Results No significant changes in COHb levels were seen in samples stored either in refrigeration or at room temperature over a period of 28 days or in samples shipped without refrigeration locally or across the United States. Conclusions Carboxyhemoglobin levels in whole blood samples anticoagulated with heparin are stable with or without refrigeration for up to 4 weeks. If COHb measurement capability is not available, such samples may be shipped or transported with patients with confidence that the COHb level will be stable when measured at a later time.

Although levodopa is the most effective oral PD therapy, many patients experience motor fluctuations, including sudden loss of dose effect and delayed benefit. CVT-301 is a levodopa inhalation powder with the potential for rapid onset of action. The objective of this study was to evaluate CVT-301 self-administered by PD patients to relieve OFF episodes.PD patients with ≥2 hours per day of OFF time despite oral levodopa ≥4 times per day were randomized to CVT-301 or placebo for 4 weeks, to be used up to 3 times per day for OFF episodes. After 2 weeks, the study-drug dose was escalated from 35 to 50 mg. The primary end point was mean change in UPDRS Part III score from a predose OFF state to the average of postdose scores obtained at 10, 20, 30, and 60 minutes, as assessed in-clinic at the end of week 4. Home diaries were recorded.Eighty-six patients used the study drug at an average frequency of 2.1 times per day for CVT-301 and for placebo. At 4 weeks, least-squares mean change in UPDRS Part III score favored CVT-301 by 7.0 points (P0.001). A treatment effect was evident at 10 minutes. At 4 weeks, least-squares mean OFF-time change from baseline favored CVT-301 by 0.9 hours per day (P = 0.045). The most frequently reported adverse events in the CVT-301 group were dizziness, cough, and nausea, each in 7% (3 of 43 patients).CVT-301 self-administered during OFF episodes provided rapid improvement of motor function, and daily OFF time was significantly reduced at the higher dose. CVT-301 was generally safe and well-tolerated. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

The evidence supporting many beliefs in medicine is based upon opinion, personal experience, hearsay, or "common knowledge." When one searches for the data supporting oft-quoted facts in medicine, they are sometimes found to be old, incorrect, or nonexistent. Such unsupported facts or beliefs can be termed myths. This minireview will summarize 4 examples of "myth busting" by the author when he has discovered widely held beliefs regarding carbon monoxide (CO) poisoning to be untrue during a 25-year career of research in the field. These include the mistaken beliefs that (1) symptoms correlate with presenting blood carboxyhemoglobin levels, (2) residents are safe from CO poisoning if their home does not contain fuel-burning appliances, (3) carboxyhemoglobin levels must be measured rapidly and on arterial blood, and (4) CO poisoning predisposes to premature long-term death from cardiac disease. In addition to providing the evidence disproving these myths, the importance of going back to the original reference when citing prior work is emphasized.

Measurement of air pollutant levels in the environment is traditionally performed using monitors in fixed locations so that changes over time can be directly compared. Such measurements do not necessarily correlate with the level of exposure to the individual because of distance to the monitoring site and other factors. In the case of carbon monoxide (CO), portable personal monitors are available for industrial use, some of which do not just alarm, but also record measured values.First, it was the purpose of this study to test the feasibility of continuously measuring ambient CO levels in an ambulatory fashion. The second objective was to compare measurements made in a country with significant air pollution to one without to determine the degree to which differences might be observed.Ambient CO levels were measured and recorded every 10 minutes during 13 days of travel in Vietnam. A parallel study was performed in the United States for comnarison.Continuous ambient CO levels at an individual level were successfully measured and recorded. Mean ambient CO level throughout Vietnam was 3.5 ± 4.4 ppm, as compared to 0.9 ± 0.8 ppm in the U.S. (p0.001). In Vietnam, 36 CO measurements (2% of total) were 15 ppm or greater vs. none in the U.S. Higher mean levels, as well as number and magnitude of peaks, were highly associated with proximity to traffic.Personal exposures to CO can be measured easily over time and may be more relevant to the individual with underlying disease than data from fixed monitoring stations. Such information may prove useful to potential travelers. Additionally, governmental agencies may find ambulatory measurement to be complimentary to data from fixed monitoring stations when attempting to estimate how traditionally collected data relate to exposure of the individual. The technique could also be used for evaluation of vague complaints suggestive of intermittent CO exposure in the home or workplace.

Highway vehicle CO emissions have decreased 85% since introduction of the catalytic converter in 1975. We sought to examine whether morbidity and mortality from intentional motor vehicle-related CO poisoning have also changed.Vehicle CO emissions data from 1970-2013 were obtained from the U.S. Environmental Protection Agency. U.S. Centers for Disease Control and Prevention data were used for the suicide crude death rate (CDR) from CO poisoning from 1999-2010. Data on non-fatal intentional CO poisonings treated at a regional hyperbaric treatment center from 1981-2013 were analyzed with regard to numbers treated and presenting carboxyhemoglobin (COHb) levels.Since 1985, the CDR for suicidal motor vehicle-related CO poisoning has decreased in parallel with CO emissions (R2 = 0.985). Non-fatal motor vehicle-related intentional CO poisoning cases decreased 63% over 33 years (p = 0.0017). COHb levels decreased 35% in these patients (p0.0001).There has been a decrease in both fatal and non-fatal intentional CO poisoning from motor vehicle exhaust since the 1980s. This correlates with reductions in vehicle CO emissions and is a likely result of the U.S. Clean Air Act of 1970 and the application of catalytic converters since 1975.

Most case definitions for carbon monoxide (CO) poisoning include demonstration of an elevated blood carboxyhemoglobin (COHb) concentration. Further, it is generally believed that treatment of CO poisoning is more effective when performed as soon as possible after the exposure. This suggests that a hospital's inability to measure blood COHb could lead to delayed or missed diagnosis or treatment. This study evaluated the ability of hospitals in the Pacific Northwest to measure COHb levels. The clinical laboratory of every acute care hospital in Washington, Idaho, Montana, and Alaska was surveyed regarding the ability to measure COHb levels, the method utilized and the time required. If they could not measure COHb, they were asked whether samples are sent elsewhere, the location of the referral laboratory, and time required. Results were then compared to the list of hospitals referring CO-poisoned patients to a regional center for hyperbaric oxygen therapy from 2003-2004. In the four states, only 44% of acute care hospitals have the capability to measure COHb. The remaining 56% send blood samples to other laboratories. The average time to get a result is 10 +/- 10 min in hospitals with co-oximetry and 904 +/- 1360 min in those without, a difference of 15 h (p < 0.0001). When samples are sent out, the average distance is 121 miles, often bypassing a hospital with CO-oximetry capability. Over 90% of CO-poisoned patients referred for hyperbaric treatment came from hospitals able to measure COHb. Fewer than one-half of acute care hospitals in a four-state region have the capability to measure COHb levels. This has the potential to significantly impact diagnosis or treatment of patients with acute CO poisoning.

Purpose Recent data demonstrate that the mortality rate from carbon monoxide poisoning has declined over the past 2 decades. It is not known whether this decrease in mortality is reflective of the total burden of carbon monoxide poisoning. This study sought to examine trends in other potential indicators of the incidence of carbon monoxide poisoning in the United States. Basic Procedures Published data from US poison control centers (PCCs) were used to calculate annual rates of calls regarding carbon monoxide exposures. Data on numbers of carbon monoxide–poisoned patients treated with hyperbaric oxygen (HBO) were used to calculate annual treatment rates. Trends in rates of carbon monoxide–related mortality, calls to PCCs, and HBO treatment were then compared. Main Findings Contrary to the decline in carbon monoxide–related mortality from 1968 to 1998, rates of calls to PCCs significantly increased over the same period. Neither rates of PCC calls nor HBO treatment changed significantly from 1992 to 2002. The latter 2 measures were strongly correlated. Principal Conclusions Although deaths from carbon monoxide poisoning have clearly decreased in the United States, other indicators of the incidence of the condition suggest that the total burden (fatal and nonfatal) may not have significantly changed. Efforts to prevent carbon monoxide poisoning should not be relaxed.

OBJECTIVE To assess the effects of hyperbaric oxygen (HBO2; often used to treat haemorrhagic cystitis, a known side-effect after radiation therapy for prostate cancer and with the potential to induce tumour angiogenesis and stimulate latent recurrence) on indolent in vivo prostate cancer in a murine model. MATERIALS AND METHODS Human prostate LNCaP cells were injected into 60 severe combined-immunodeficient mice; of these 24 (40%) did not develop palpable tumours after 6 weeks. They were randomized to undergo 20 sessions of either HBO2 or normobaric air in standardized conditions, and observed for another 4 weeks before the histological assessment of any palpable tumours that developed. Analysis of developed LNCaP tumours included tumour volume, microvessel density, MIB-1, p53, p27 and racemase staining intensity. RESULTS HBO2 was associated with less prostate tumour progression than normobaric air (P = 0.26). During HBO2 therapy, 10 mice remained free of palpable tumours, compared with seven controls (P = 0.30). On evaluation during the 4 weeks after therapy, six mice treated with HBO2 remained free of palpable tumours, vs eight of the controls (P = 0.17). There was tumour invasion and necrosis in a two of six and four of the HBO2 group during and after therapy, respectively, vs five and seven of the controls. Tumour microvessel density, proliferative index, differentiation and apoptosis markers were similar in both groups. CONCLUSIONS HBO2 does not accelerate the growth of indolent prostate cancer in a murine model, suggesting that it does not increase the risk of residual prostate cancer reactivation when it is used to manage radiation-induced haemorrhagic cystitis in patients treated by pelvic radiotherapy for prostate cancer.

Hypothesis This study investigated whether pressure changes common to scuba diving and to hyperbaric oxygen therapy would not cause crush damage or leakage from critical seals in commercially available cochlear implants. Background The implanted packages of cochlear implants are susceptible to electrical failure caused by leakage from critical seals and to crush injury when exposed to changing barometric pressures encountered in recreational diving and in hyperbaric oxygen therapy. Methods Six Clarion 1.2, eight MED-EL Combi-40+, six Nucleus CI22M, and six Nucleus CI24M cochlear implants underwent three exposures at 165 feet of seawater (FSW) (6 ata abs), 99 FSW (4 ata abs), and 60 FSW (2.8 ata abs), simulating rates in accordance with U.S. Navy dive tables for nondecompression dives. Dives to 45 FSW (2.4 ata abs) simulated wound therapy. Before each dive began, after each dive, and after completion of the dive protocol, each device underwent telemetry and electrical integrity checks. All implants were returned to their respective factories for final electrical and quality control testing. Results All 26 devices completed the dive protocol. One Nucleus CI24M implant had a fault recorded at electrode lead 18 on predive and final product testing, which was absent during interval dive measurements. All 26 devices passed final electrical and quality control testing. In addition, the six Clarion units passed repeat helium leak testing. Conclusion The implanted components of the Clarion 1.2, MED-EL Combi-40+, and Nucleus CI22M and CI24M were safely subjected to repeated pressure changes up to 6 atm abs, equivalent to 165 feet of seawater, without electrical failure from leakage at critical seals or crush damage.

OBJECTIVE: To evaluate systematically the characteristics of headache due to acute exposure to carbon monoxide. BACKGROUND: Headache is the most commonly reported symptom in acute carbon monoxide poisoning. While it is often described as throbbing and diffuse, a systematic characterization of carbon monoxide-associated headache has never been published. METHODS: Patients referred for hyperbaric oxygen treatment of acute carbon monoxide poisoning were asked whether headache was part of their symptom complex. When present, specific details about the nature of the headache were collected from 100 consecutive patients through use of a standardized questionnaire. RESULTS: Information on carbon monoxide-associated headache was collected from 34 female and 66 male patients with a mean carboxyhemoglobin level of 21.3%+/- 9.3%. The most common location for pain was frontal (66%), although more than one location was involved in 58% of patients. Nature of the pain at any time during its course was dull in 72% of patients and sharp in 36%. Headache was throbbing in 41%, continuous in 74%, and intermittent in 16% of those evaluated. Peak intensity of pain did not correlate with the carboxyhemoglobin level. Headache improved prior to hyperbaric oxygen treatment in 72%, resolving entirely in 21%. Of those with residual headache, pain improved with hyperbaric oxygen in 97%, resolving entirely in 44%. CONCLUSION: The headache accompanying acute carbon monoxide poisoning is extremely variable in nature. "Classic" throbbing, diffuse headaches were rarely described by patients. There are no patterns which can be considered characteristic to aid in the diagnosis of carbon monoxide-induced headache. Similarly, no trait was identified which might allow elimination of carbon monoxide poisoning from the differential diagnosis of headache. Language: en

Context Although morbidity and mortality from accidental carbon monoxide (CO) poisoning are high in the United States, identification of common but poorly recognized sources should help prevention efforts. Objective The study aimed to describe CO poisoning of home occupants due to a vehicle left running in an attached garage. Design News stories reporting incidents of US CO poisoning were collected daily from March 2007 to September 2009 via a news.Google.com search and data extracted. Patients Patients were individuals reported in the media to have been poisoned with CO in their home by a vehicle running in the attached garage. Main Outcome Measures Main outcome measures were frequency of occurrence, geographic distribution, patient demographics, and mortality. Results Of 837 CO poisoning incidents reported in US news media over 2 and a half years, 59 (8%) were the result of a vehicle left running in the garage. The elderly were disproportionately affected, with incidents most common in states with larger elderly populations and 29% of cases with age specified occurring in individuals older than 80 years. Among those older than 80 years, 15 of 17 were found dead at the scene. Conclusions Residential CO poisoning from a vehicle running in the garage is common, disproportionately affects the elderly, has a high mortality rate, and should be preventable with a residential CO alarm.

For decades, physicians have been taught to look for “cherry red” coloration of the skin and mucous membranes in patients with carbon monoxide (CO) poisoning, but this is rarely seen [1,2]. In 1857, Hoppe in Germany first described the change in blood color when hemoglobin is loaded with CO [3]. Because carboxyhemglobin (COHb) is a brighter shade of red than oxyhemglobin and the color of capillary blood contributes to skin color, it would seem reasonable that a poisoned patient’s appearance might change with sufficient amounts of circulating COHb. However, a lethal level of COHb is required for a human’s skin and mucous membranes to appear “cherry red”. Even when reflectance spectrometry is used to measure skin color after death in individuals who have died of CO poisoning, less than one-half demonstrate “cherry red” skin [4]. Recently, however, “cherry red” urine has been described in a subgroup of individuals with acute CO poisoning [5].

A critically ill man with drug-induced hemolytic anemia and hepatic failure was hospitalized at a private academic medical center in Seattle, Washington. Intravascular hemolysis with associated endogenous carbon monoxide (CO) production resulted in elevation of the patient's carboxyhemoglobin (COHb) level to as high as 9.7%. Serial measurements of the patient's COHb level were obtained and compared with other conventional measures of hemolytic activity. With the availability of new non-invasive measurement technology to detect COHb elevations, emergency clinicians are likely to see COHb elevation as a manifestation of hemolytic anemia.

This study was conducted to determine the annual number of emergency department (ED) visits and rate of hyperbaric oxygen (HBO2) treatment for carbon monoxide (CO) poisoning in Washington, Idaho, and Montana. All hospital emergency departments and hyperbaric treatment facilities in the region were surveyed by mail and telephone regarding their patient treatment experience for calendar year 1994. Results demonstrated that there were approximately 2.51 million total ED visits in 1994 in the three states studied. Among these, an estimated 1,325 individuals were seen with carbon monoxide poisoning (52.9 CO cases per 100,000 ED visits; 18.1 CO cases per 100,000 population). A total of 91 patients were treated with HBO2, yielding an HBO2 treatment rate of 6.9% of those evaluated in EDs. Extrapolating these figures to the US population suggests that the number of individuals seeking emergency medical care for CO poisoning is much greater than is commonly quoted. Even after correcting for the known increased rate of CO poisoning in the Pacific Northwest, the incidence of nonfatal poisoning appears to be significantly higher than may be appreciated from previous reports.

Purpose :The purpose of this article is (1) to describe our method of mechanical ventilation and monitoring of critically ill children during administration of hyperbaric oxygen therapy (HBO2) in a multiplace chamber; and (2) to review the complications they experienced during transport to the HBO2 chamber and HBO2 treatment. Materials and Methods :A case series from a universitya-ffiliated children's hospital and regional hyperbaric medicine treatment facility. Patients studied included all children who required HBO2 therapy while mechanically ventilated at any time between April 1985 and June 1995. Results :Thirty-two children were treated with HBO2 while mechanically ventilated. Ages ranged from 3 days to 11.3 years (mean 4.8 ± 3.5 years). There were 22 males. Twenty-one children had necrotizing infections, 9 had carbon monoxide (CO) poisoning, and 2 had iatrogenic arterial air embolism. Complications or events occurring during HBO2 therapy included hypotension (63%), bronchospasm (34%), hemotympanum (13%), and progressive hypoxemia (6%). The only complication during transport was one accidental extubation (3%). Conclusion :Hyperbaric oxygen therapy can be administered safely to most critically ill children in a multiplace chamber if they are monitored closely. Although complications are not uncommon, most can be managed easily by a team skilled in treating ill children and knowledgeable of possible complications of HBO2 therapy.

Pulmonary embolism is a common disease in the United States, affecting as many as 500,000 persons annually. Unfortunately, this disorder is commonly undiagnosed, resulting in significant excess morbidity and mortality. The clinical symptoms and signs caused by pulmonary embolism are nonspecific and may be confused with a variety of other cardiopulmonary disorders having similar presentations. However, accurate diagnostic tests are available for diagnosing pulmonary embolism, even in the face of coexistent cardiopulmonary disorders. This article describes the clinical characteristics of pulmonary venous thromboembolism, reviewing its typical symptoms and signs, its routine laboratory tests, and chest radiographic abnormalities.

Study objective To evaluate histologic, microbiological, and clinical criteria in the recognition of ventilator-associated pneumonia (VAP) in patients who died while mechanically ventilated. Methods The study group consisted of 39 patients who died after a mean of 14 days of mechanical ventilation. Postmortem fiberoptic bronchoscopy (FOB) and open lung biopsy were performed with collection of specimens initiated 3 in the 48 h prior to death, presence of a bacterial or fungal pathogen on the last sputum culture, radiographic worsening in the week prior to death, and worsening gas exchange defined as a 15% decrease in the PaO 2 /fraction of inspired oxygen ratio in the 72 h prior to death. Results None of the quantitative cultures had a reliable positive predictive value for histologic pneumonia. None of the five clinical criteria tested showed agreement with the presence or absence of histologic pneumonia. There was a significant correlation between qualitative and quantitative microbiological results from the distal airway/FOB-guided PSB, distal airway/BALF, and quantitative culture of the lung parenchyma. Also, suction catheter aspirate of the trachea had a sensitivity of 87% in recognizing the bacterial species simultaneously present in lung parenchyma. None of the patients with histologic pneumonia had Conclusions Neither the bacterial density from the four airway quantitative cultures, nor the bacterial density from quantitative culture of lung parenchyma accurately separated the histologic pneumonia and nonpneumonia groups. No clinical criteria or combination of clinical criteria correlated with the presence or absence of histologic pneumonia. A BALF with

Hospital emergency departments were surveyed to estimate the number of patients treated for carbon monoxide (CO) poisoning after a severe winter storm disrupted electrical service in western Washington State. At least 81 persons were treated. The two main sources of CO were charcoal briquettes (54% of cases) and gasoline-powered electrical generators (40% of cases). Of the 44 persons affected by CO from burning charcoal, 40 (91%) were members of ethnic minority groups; 27 did not speak English. All persons affected by CO from generators were non-Hispanic Whites. This was the largest epidemic of storm-related CO poisoning reported in the United States. This epidemic demonstrated the need to anticipate CO poisoning as a possible consequence of winter storms in cold climates and to make preventive messages understandable to the entire population at risk, including those persons who do not understand written or spoken English.

Hyperbaric oxygen treatment (HBO2) is used commonly for treatment of bone and soft-tissue radiation necrosis. It may be a potential therapy for radiation necrosis seen after brain irradiation. HBO2 risks include generalized tonic-clonic convulsions. We report a patient after resection of anaplastic astrocytoma and 5,580 cGy of total external-beam radiation treatments with brain radiation necrosis who underwent HBO2 therapy and developed a partial seizure during treatment. Mechanisms and implications are discussed.

Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft.A handheld mountaineering altimeter was carried by the investigators in the plane cabin during commercial air travel and peak cabin altitude measured. The values were then compared between aircraft models, aircraft classes, and distances flown.The average peak cabin altitude on 207 flights aboard 17 different aircraft was 6341 +/- 1813 ft (1933 m +/- 553 m), significantly higher than when measured in a similar fashion in 1988. Peak cabin altitude was significantly higher for flights longer than 750 mi (7085 +/- 801 ft) compared to shorter flights (5160 +/- 2290 ft/1573 +/- 698 m). Cabin altitude increased linearly with flight distance for flights up to 750 mi in length, but was independent of flight distance for flights exceeding 750 mi. Peak cabin altitude was less than 5000 ft (1524 m) in 70% of flights shorter than 500 mi. Peak cabin altitudes greater than 8000 ft (2438 m) were measured on approximately 10% of the total flights.Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.