Carbon monoxide poisoning and subsequent cardiovascular disease risk: a nationwide population-based cohort study

Air Pollution and Cardiac Diseases: A Review of Experimental Studies

Air pollution is associated with around 6.5 million premature deaths annually, which are directly related to cardiovascular diseases, and the most dangerous atmospheric pollutants to health are as follows: NO2, SO2, CO, and PM. The mechanisms underlying the observed effects have not yet been clearly defined. This work aims to conduct a narrative review of experimental studies to provide a more comprehensive and multiperspective assessment of how the effect of atmospheric pollutants on cardiac activity can result in the development of cardiac diseases. For this purpose, a review was carried out in databases of experimental studies, excluding clinical trials, and epidemiological and simulation studies. After analyzing the available information, the existence of pathophysiological effects of the different pollutants on cardiac activity from exposure during both short-term and long-term is evident. This narrative review based on experimental studies is a basis for the development of recommendations for public health.

Carbon monoxide poisoning: beyond survival - mortality, morbidities, and risk factors, a Turkey sample

Background

We aimed to investigate the effect of poisoning on mortality leading to new morbidities in people who survived the poisoning.

Methods

The descriptive-retrospective study evaluated all carbon monoxide poisoning cases between 2012 and 2022 in the Adiyaman. For the fatality, all cases were followed up through Turkey's death notification system until the end of 2022. One-year health records of cases treated as inpatients in Adiyaman hospitals were analyzed for nine diagnoses. A total of 4,395 carbon monoxide cases, recorded over 11 years, were all noted to be accidental cases.

Results

The rate of carbon monoxide poisoning in Adıyaman was calculated as 63.2 per hundred thousand. A total of 87 (2%) of the cases died. The population's hospitalization rate was 1.71, while the mortality rate was 1.25 in a hundred thousand. Among the cases, the hospitalization rate was 2.7, and the admission to intensive care rate was 1.7. The fatality rate was 6.5% for those hospitalized and 12.2% for those admitted to the intensive care unit. The highest fatality rate was 65.5% in patients aged 65 and above. One out of five morbidities was developed in 8.4% of cases within one year. The fatality rate of those who developed morbidities (40%) was higher than those who did not (5.5%). Being male posed a 1,886-fold risk for mortality, and each increase in age posed a 1,086-fold risk for mortality.

Conclusion

Individuals who had carbon monoxide poisoning should be followed up closely for one year after poisoning due to the possibility of the emergence of new morbidities that increase the risk of mortality.

CORM-A1 Alleviates Pro-Atherogenic Manifestations via miR-34a-5p Downregulation and an Improved Mitochondrial Function

Atherogenesis involves multiple cell types undergoing robust metabolic processes resulting in mitochondrial dysfunction, elevated reactive oxygen species (ROS), and consequent oxidative stress. Carbon monoxide (CO) has been recently explored for its anti-atherogenic potency; however, the effects of CO on ROS generation and mitochondrial dysfunction in atherosclerosis remain unexplored. Herein, we describe the anti-atherogenic efficacy of CORM-A1, a CO donor, in in vitro (ox-LDL-treated HUVEC and MDMs) and in vivo (atherogenic diet-fed SD rats) experimental models. In agreement with previous data, we observed elevated miR-34a-5p levels in all our atherogenic model systems. Administration of CO via CORM-A1 accounted for positive alterations in the expression of miR-34a-5p and transcription factors/inhibitors (P53, NF-κB, ZEB1, SNAI1, and STAT3) and DNA methylation pattern, thereby lowering its countenance in atherogenic milieu. Inhibition of miR-34a-5p expression resulted in restoration of SIRT-1 levels and of mitochondrial biogenesis. CORM-A1 supplementation further accounted for improvement in cellular and mitochondrial antioxidant capacity and subsequent reduction in ROS. Further and most importantly, CORM-A1 restored cellular energetics by improving overall cellular respiration in HUVECs, as evidenced by restored OCR and ECAR rates, whereas a shift from non-mitochondrial to mitochondrial respiration was observed in atherogenic MDMs, evidenced by unaltered glycolytic respiration and maximizing OCR. In agreement with these results, CORM-A1 treatment also accounted for elevated ATP production in both in vivo and in vitro experimental models. Cumulatively, our studies demonstrate for the first time the mechanism of CORM-A1-mediated amelioration of pro-atherogenic manifestations through inhibition of miR-34a-5p expression in the atherogenic milieu and consequential rescue of SIRT1-mediated mitochondrial biogenesis and respiration.

Morbidity and Mortality of Unintentional Carbon Monoxide Poisoning: United States 2005 to 2018

STUDY OBJECTIVE

Centers for Disease Control and Prevention conducts case surveillance through the National Notifiable Diseases Surveillance System (NNDSS). This study aimed to provide surveillance report of unintentional carbon monoxide poisoning across multiple data sources to provide baseline data for the new NNDSS carbon monoxide poisoning surveillance.

METHODS

For the period 2005 to 2018, we used 4 data sources to describe unintentional carbon monoxide poisoning: exposures reported by poison centers, emergency department (ED) visits, hospitalizations, and deaths. We conducted descriptive analyses by the cause of exposure (fire, nonfire, or unknown), age, sex, season, and US census region. Additional analyses were conducted using poison center exposure case data focusing on the reported signs and symptoms, management site, and medical outcome.

RESULTS

Annually, we observed 39.5 poison center exposure calls (per 1 million, nationally), 56.5 ED visits (per 1 million, across 17 states), 7.3 hospitalizations (per 1 million, in 26 states), and 3.3 deaths (per 1 million, nationally) due to unintentional carbon monoxide poisoning. For 2005 to 2018, there was a decrease in the crude rate for non-fire-related carbon monoxide poisonings from hospital, and death data. Non-fire-related cases comprised 74.0% of ED visits data, 60.1% of hospitalizations, and 40.9% of deaths compared with other unintentional causes. Across all data sources, unintentional carbon monoxide poisonings were most often reported during the winter season, notably in January and December. Children aged 0 to 9 years had the highest reported rates in poison center exposure case data and ED visits (54.1 and 70.5 per 1 million, respectively); adults older than 80 years had the highest rates of hospitalization and deaths (20.2 and 9.9 per 1 million, respectively); and deaths occurred more often among men and in the Midwest region. Poison center exposure call data revealed that 45.9% of persons were treated at a health care facility. Headaches, nausea, and dizziness/vertigo were the most reported symptoms.

CONCLUSION

The crude rates in non-fire-related carbon monoxide poisonings from hospitalizations, and mortality significantly decreased over the study period (ie, 2005 to 2018). This surveillance report provides trends and characteristics of unintentional carbon monoxide poisoning and the baseline morbidities and mortality data for the Centers for Disease Control and Prevention national surveillance system of carbon monoxide poisoning.

Biomass using tribal women exhibited respiratory symptoms, hypertensive risks and abnormal pulmonary function

In rural areas of developing countries, solid fuels are still widely used for cooking, heating, and lighting purposes. This study investigates the effects of household air pollutants (HAPs) exposure on the occurrence of respiratory symptoms, blood pressure, and lung function. In this study, we randomly selected 123 (83 biomass and 40 clean fuel user) subjects to assess the impact of smoke generated from solid biomass fuel by assessing their health status along with the ventilation pattern of the kitchens and living rooms. HAPs (PM10, PM2.5, and CO) and different health parameters were measured along with monitoring of self-reported health symptoms for a consecutive period of eight months. Results revealed that the concentration of CO, PM2.5, and PM10 were found highest in biomass using households. Higher odds of the upper respiratory symptoms, runny nose (OR: 4.08, 95% CI: 1.22-22.14, p < 0.03), nasal congestion (OR: 9.07, 95% CI: 1.39-97.89, p < 0.01) and the odds of the lower respiratory symptoms like wheezing (OR: 1.62, 95% CI: 1.23-10.94, p < 0.01), breathlessness (OR: 4.44, 95% CI: 1.3-14.75, p < 0.01), chest tightness (OR: 4.89, 95% CI: 1.23-22.14, p < 0.03) and dry cough (OR: 3.661, 95% CI: 1.05-12.25, p < 0.04) were significantly higher in biomass fuel user. Similarly higher systolic (+11.41 mmHg), higher diastolic pressure (+3.3 mmHg), higher pulse pressure (+8.11 mmHg), and a 6 mmHg higher mean arterial pressure among biomass fuel using tribal women. The risk of hypertension was significantly (p < 0.03) higher (OR: 3.04; 95% CI: 1.18-7.89) among solid biomass fuel users. The lung abnormality was recorded 28.91% (OR: 5.02, 95% CI: 1.50 to 16.56, p < 0.01) among biomass fuel user. Finally, it is suggested that the use of efficient cookstoves, increase in cross ventilation, and cleaner fuel are urgently needed to curb the pollution load.

Structural, Optical, and Sensing Properties of Nb-Doped ITO Thin Films Deposited by the Sol–Gel Method

The aim of the present study was the development of Nb-doped ITO thin films for carbon monoxide (CO) sensing applications. The detection of CO is imperious because of its high toxicity, with long-term exposure having a negative impact on human health. Using a feasible sol–gel method, the doped ITO thin films were prepared at room temperature and deposited onto various substrates (Si, SiO2/glass, and glass). The structural, morphological, and optical characterization was performed by the following techniques: X-ray diffractometry (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV/Vis/NIR spectroscopic ellipsometry (SE). The analysis revealed a crystalline structure and a low surface roughness of the doped ITO-based thin films. XTEM analysis (cross-sectional transmission electron microscopy) showed that the film has crystallites of the order of 5–10 nm and relatively large pores (around 3–5 nm in diameter). A transmittance value of 80% in the visible region and an optical band-gap energy of around 3.7 eV were found for dip-coated ITO/Nb films on SiO2/glass and glass supports. The EDX measurements proved the presence of Nb in the ITO film in a molar ratio of 3.7%, close to the intended one (4%). Gas testing measurements were carried out on the ITO undoped and doped thin films deposited on glass substrate. The presence of Nb in the ITO matrix increases the electrical signal and the sensitivity to CO detection, leading to the highest response for 2000 ppm CO concentration at working temperature of 300 °C.

Rare Causes of Acute Coronary Syndrome: Carbon Monoxide Poisoning

Acute coronary syndrome (ACS) is a spectrum of clinical and paraclinical disorders arising from an imbalance of oxygen demand and supply to the myocardium. The most common cause is atherosclerosis; however, other rare causes such as carbon monoxide (CO) poisoning should be considered. Through tissue hypoxia and direct cell injury, CO poisoning can lead to a broad spectrum of cardiac disorders, especially ACS. Materials and Methods. We have conducted a retrospective study in the Toxicology Department of Saint Spiridon Emergency University Hospital, including all patients admitted through the emergency department with CO poisoning. We divided the cohort into event group (myocardial injury) and non-event group (patients without myocardial injury) and performed a subset analysis of the former. Results. A total of 65 patients were included, 22 in the event and 43 in the non-event group. The severity of poisoning did not correlate with myocardial injury; however, 50% of the event group had severe poisoning with carboxyhaemoglobin ≥ 20%. Cardiac enzyme markers (troponin and creatin-kinase MB) had a statistically significant increase in the event group compared to the non-event group (p < 0.05). Most of the patients in the STEMI (50%) and NSTEMI (66.7%) groups had severe CO intoxication. The STEMI group had a mean age of 27.7 years old and no comorbidities. Conclusions. Myocardial injury can develop in CO poisoning irrespective of the severity of poisoning, and it can be transient, reversible, or permanent. Our study introduces new information on adverse cardiac events in patients with CO poisoning, focusing on the ACS. We found that the severity of CO poisoning plays an important role in developing myocardial injury, as 50% of patients in the event group were severely intoxicated. While in-hospital mortality in our study was low, further prospective studies should investigate the long-term mortality in these patients.

S2k guideline diagnosis and treatment of carbon monoxide poisoning

Carbon monoxide (CO) can occur in numerous situations and ambient conditions, such as fire smoke, indoor fireplaces, silos containing large quantities of wood pellets, engine exhaust fumes, and when using hookahs. Symptoms of CO poisoning are nonspecific and can range from dizziness, headache, and angina pectoris to unconsciousness and death. This guideline presents the current state of knowledge and national recommendations on the diagnosis and treatment of patients with CO poisoning. The diagnosis of CO poisoning is based on clinical symptoms and proven or probable exposure to CO. Negative carboxyhemoglobin (COHb) levels should not rule out CO poisoning if the history and symptoms are consistent with this phenomenon. Reduced oxygen-carrying capacity, impairment of the cellular respiratory chain, and immunomodulatory processes may result in myocardial and central nervous tissue damage even after a reduction in COHb. If CO poisoning is suspected, 100% oxygen breathing should be immediately initiated in the prehospital setting. Clinical symptoms do not correlate with COHb elimination from the blood; therefore, COHb monitoring alone is unsuitable for treatment management. Especially in the absence of improvement despite treatment, a reevaluation for other possible differential diagnoses ought to be performed. Evidence regarding the benefit of hyperbaric oxygen therapy (HBOT) is scant and the subject of controversy due to the heterogeneity of studies. If required, HBOT should be initiated within 6 h. All patients with CO poisoning should be informed about the risk of delayed neurological sequelae (DNS).

Carbon Monoxide Poisoning and Developing Ischemic Heart Disease: A Nationwide Population-Based Nested Case-Control Study

Although there are several case reports showing that carbon monoxide (CO) poisoning causes ischemic heart disease (IHD), no large-scale epidemiological studies have shown a significant association between the two. To investigate the association between CO poisoning and IHD, a nested case-control study of 28,113 patients who experienced CO poisoning and 28,113 controls matched by sex and age was performed using the nationwide health database of South Korea. Based on a conditional logistic regression, there was a significantly higher risk of IHD among the CO poisoning group than among the control group (adjusted hazard ratio [HR], 2.16; 95% confidence interval [CI], 1.87–2.49). The risk of IHD after CO poisoning was higher among the younger age group under 40 years (adjusted HR, 4.85; 95% CI, 3.20–7.35), and it was much greater among those with comorbidities (adjusted HR, 10.69; 95% CI, 2.41–47.51). The risk of IHD was the highest within the first two years after CO poisoning (adjusted HR, 11.12; 95% CI, 4.54–27.22). Even if more than six years had passed, the risk was still significantly higher than among the control group (adjusted HR, 1.55; 95% CI, 1.27–1.89). The analyses imply that CO poisoning is associated with an increased risk of IHD.

Evaluation of the Cardioprotective Effect of Granulocyte Colony Stimulating Factor in Patients with Carbon Monoxide Poisoning

BACKGROUND

Carbon monoxide (CO), which is well known as silent killer, has many toxic effects on organs with high rate of metabolism such as heart and brain. CO-induced cardiotoxicity resulted in a wide range of disabilities including electrocardiogram (ECG) abnormalities, elevation in level of cardiac enzymes, arrhythmias, impairment of left ventricular and myocardial infarction (MI). Cardio-protective effects of Granulocyte colony-stimulating factor (G-CSF) on infarcted heart was proved previously in various reports.

OBJECTIVE

In this study, possible effect of G-CSF on cardiac function of patients with moderate to severe acute CO poisoning was investigated.

METHODS

Cardioprotective effects of G-CSF in CO-poisoned patients was evaluated through ECG, Holter monitoring, echocardiography, and biochemical studies. Continuous intravenous infusion of G-CSF (90 μg/kg) and normal saline were administered respectively to treatment and placebo groups.

RESULTS

The results demonstrated that in moderate to severe CO poisoning, myocardial injury is common. ECG changes (e.g., ST-segment and T-wave changes, QTC), cardiac arrhythmias (e.g., heart blocks and ventricular arrhythmias), serum level of Troponin I, left ventricular ejection fraction were determined after G-CSF administration. Frequencies of ST depression, inversion or flatting of T wave and QTC in ECG were significantly reduced after G-CSF treatment. In addition, incidence of cardiac arrhythmias due to CO poisoning were reduced after G-CSF treatment. However, G-CSF did not exert protective effects on TPI level and function of left ventricular in CO-poisoned patients.

CONCLUSION

GCSF could probably reduce CO-induced cardiac ischemia in patients with acute CO poisoning.

CLINICAL TRIAL REGISTRATION

The trial protocol was registered in the Iranian Registry of Clinical Trials (http://www.irct.ir) registry (Irct ID: IRCT201607232083N7).

Increased Risk of Congestive Heart Failure Following Carbon Monoxide Poisoning

BACKGROUND

Carbon monoxide poisoning (COP) is an important public health issue around the world. It may increase the risk of myocardial injury, but the association between COP and congestive heart failure (CHF) remains unclear. We conducted a study incorporating data from epidemiological and animal studies to clarify this issue.

METHODS

Using the National Health Insurance Database of Taiwan, we identified patients with COP diagnosed between 1999 and 2012 and compared them with patients without COP (non-COP cohort) matched by age and the index date at a 1:3 ratio. The comparison for the risk of CHF between the COP and non-COP cohorts was made using Cox proportional hazards regression. We also established a rat model to evaluate cardiac function using echocardiography and studied the pathological changes following COP.

RESULTS

The 20 942 patients in the COP cohort had a higher risk for CHF than the 62 826 members in the non-COP cohort after adjusting for sex and underlying comorbidities (adjusted hazard ratio, 2.01 [95% CI, 1.74-2.32]). The increased risk of CHF persisted even after 2 years of follow-up (adjusted hazard ratio, 1.85 [95% CI, 1.55-2.21]). In the animal model, COP led to a decreased left ventricular ejection fraction on echocardiography and damage to cardiac cells with remarkable fibrotic changes.

CONCLUSIONS

Our epidemiological data showed an increased risk of CHF was associated with COP, which was supported by the animal study. We suggest close follow-up of cardiac function for patients with COP to facilitate early intervention and further studies to identify other long-term effects that have not been reported in the literature.

The Poisoned Heart: A Case of Takotsubo Cardiomyopathy Induced by Carbon Monoxide Poisoning

BACKGROUND

Carbon monoxide is a common environmental toxin, and some patients present with features of cardiac injury in addition to the noxious effects of carbon monoxide poisoning. A very small fraction of those have a transient left ventricular apical ballooning syndrome or Takotsubo cardiomyopathy, both terms are used to define a syndrome that affects the systolic function of the heart. It usually presents with elevated troponin levels with or without electrocardiographic changes. Cardiac angiograms generally illustrate coronary arteries without significant obstruction.

CASE REPORT

Here we report the curious case of a 37-year-old Hispanic man brought in for carbon monoxide poisoning, but found to have significantly elevated troponin levels. Echocardiogram demonstrated decreased ejection fraction of 35%. Left heart catheterization 2 days after admission revealed patent coronary arteries, improved ejection fraction to 45%, and wall motion abnormalities plus apical ballooning compatible with Takotsubo cardiomyopathy. The case is unusual because our patient differs from the classically defined elderly, postmenopausal female demographic, and did not experience an emotional crisis that could have provoked this series of events. It is also noteworthy for the fact that the only identifiable trigger was exposure to carbon monoxide. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Carbon monoxide poisoning is a common occurrence resulting in a multitude of annual emergency department visits. Given the known toxic effects of carbon monoxide poisoning on the heart, prompt cardiac workup is important to prevent overlooking a major, although rare, manifestation of carbon monoxide exposure.

Diagnostic performance and optimal cut-off values of cardiac biomarkers for predicting cardiac injury in carbon monoxide poisoning

OBJECTIVE

This study aimed to compare the diagnostic performance of cardiac biomarkers and to evaluate the optimal cut-off values for echocardiographic cardiac injury prediction in patients with carbon monoxide (CO) poisoning.

METHODS

This retrospective observational cohort study included adult patients with acute CO poisoning. Patients who did not undergo transthoracic echocardiography, which was used to define patients with cardiac injury (ejection fraction <55%), were excluded. The area under the curve was used to evaluate diagnostic performance for cardiac injury prediction. Mann-Whitney U, chi-square, and Fisher exact tests were used to analyze data.

RESULTS

After excluding the 27 patients who did not undergo echocardiography, 114 patients were included in the study. Fifteen (13.2%) patients had cardiac injury. The area under the curve values for the B-type natriuretic peptide, creatine kinase-myocardial band, and troponin I were 0.711 (95% confidence interval [CI], 0.527-0.895; P=0.011), 0.766 (95% CI, 0.607-0.926; P=0.001), and 0.801 (95% CI, 0.647-0.955; P<0.001), respectively, with optimal cut-off values of 330 pg/mL, 10.1 ng/mL, and 0.455 ng/mL, respectively. The sensitivity, specificity, and positive and negative predictive values of troponin I were 67%, 91%, 53%, and 95%, respectively.

CONCLUSION

Troponin I showed the best diagnostic performance for predicting cardiac injury in patients with CO poisoning. A cut-off value of 0.455 ng/mL appeared optimal for cardiac injury prediction. However, further studies on cardiac biomarkers and other diagnostic tools in CO poisoning are needed given the low sensitivity of troponin I.

Silent Acute Coronary Syndrome in a Mild Carbon Monoxide Poisoning

Introduction: Carbon monoxide (CO) poisoning continues to be challenging in diagnosis and management. The complications related to CO poisoning are variable and unpredictable.

Case presentation: We present the case of a 73-year-old woman who was involved in an indoor fire. Although she was asymptomatic and had a low CO level, she developed an acute coronary syndrome. The condition of the patient recovered remarkably after treatment with oxygen supplementation and anti-ischemic drugs.

Conclusion: This case indicates that an acute coronary syndrome could represent a complication of CO poisoning even in asymptomatic patients with low levels of COHb.

Cardiac injury after acute carbon monoxide poisoning and its clinical treatment scheme

This study was designed to investigate cardiac injury after acute carbon monoxide poisoning and its clinical treatment scheme. Seventy patients with moderate and severe acute carbon monoxide poisoning (ACOP) admitted from January 2017 to December 2018 into The Affiliated Hospital of Qingdao University were regarded as a research group (RG), and another 30 healthy adults undergoing physical examination in the hospital during the same period were selected as a control group (CG). Thirty-five patients in the RG who received hyperbaric oxygen therapy were considered as group A, and 35 patients who received extracorporeal membrane oxygenation therapy were considered as group B. The effective rates and complications of the two groups after treatment were compared. The concentrations of creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH) of myocardial enzymes at different time points before and after treatment were detected. Expression of miR-30a in the blood of experimental subjects was detected by time-fluorescence quantitative PCR, and the relationship between miR-30a expression and ACOP patients was analyzed. Patients in groups A and B achieved obvious efficacy, but the effective rate and incidence rate of complications in the extracorporeal membrane oxygenation (ECMO) group were better than those in the hyperbaric oxygen group. The concentrations of CK-MB and LDH in group A and group B were significantly higher than those in control group (P<0.01). The expression level of miR-30a in the RG was significantly higher than that in the control group (P<0.05). Both hyperbaric oxygen therapy and ECMO therapy have obvious efficacy on ACOP patients, but the latter is better than the former. The expression level of miR-30a in blood of ACOP patients increased significantly, which is positively correlated with myocardial injury, and it decreased after treatment. It is believed that miR-30a can provide a reference index for early diagnosis and prediction of disease progression and prognosis in cardiac injury of ACOP.

The Effects of Social, Personal, and Behavioral Risk Factors and PM2.5 on Cardio-Metabolic Disparities in a Cohort of Community Health Center Patients

(1) Background: Cardio-metabolic diseases (CMD), including cardiovascular disease, stroke, and diabetes, have numerous common individual and environmental risk factors. Yet, few studies to date have considered how these multiple risk factors together affect CMD disparities between Blacks and Whites. (2) Methods: We linked daily fine particulate matter (PM2.5) measures with survey responses of participants in the Southern Community Cohort Study (SCCS). Generalized linear mixed modeling (GLMM) was used to estimate the relationship between CMD risk and social-demographic characteristics, behavioral and personal risk factors, and exposure levels of PM2.5. (3) Results: The study resulted in four key findings: (1) PM2.5 concentration level was significantly associated with reported CMD, with risk rising by 2.6% for each µg/m3 increase in PM2.5; (2) race did not predict CMD risk when clinical, lifestyle, and environmental risk factors were accounted for; (3) a significant variation of CMD risk was found among participants across states; and (4) multiple personal, clinical, and social-demographic and environmental risk factors played a role in predicting CMD occurrence. (4) Conclusions: Disparities in CMD risk among low social status populations reflect the complex interactions of exposures and cumulative risks for CMD contributed by different personal and environmental factors from natural, built, and social environments.

High-Sensitivity Troponin I and Creatinine Kinase-Myocardial Band in Screening for Myocardial Injury in Patients with Carbon Monoxide Poisoning

Myocardial dysfunction due to acute carbon monoxide (CO) poisoning is common and associated with poor outcomes. The role of cardiac markers, including creatine kinase-myocardial band (CK-MB), high-sensitivity troponin I (hsTnI), and brain natriuretic peptide (BNP), in identifying patients with CO-induced cardiomyopathy were evaluated. This single-center, retrospective cohort study included 905 consecutive adult patients in the CO poisoning registry from February 2009 to December 2019. Cardiomyopathy was defined as any abnormality on transthoracic echocardiography (TTE), including left ventricular systolic and diastolic dysfunction, right ventricular dysfunction, and wall motion abnormalities. The areas under receiver operating curves (AUCs) for biomarkers were compared. Of the 850 included patients, 101 (11.9%) had CO-induced cardiomyopathy. Initial and peak hsTnI and CK-MB concentrations, and initial BNP concentrations were significantly higher in patients with than without cardiomyopathy (all P-values < 0.01), but the AUCs were higher for hsTnI (0.894) and CK-MB (0.864) than for BNP (0.796). Initial TnI > 0.01 ng/mL and CK-MB > 1.5 ng/mL each had 95% sensitivity and 97% negative predictive value for CO-induced cardiomyopathy. Higher hsTnI or CK-MB levels on admission can identify patients at high-risk of CO-induced cardiomyopathy and can be a screening tool for CO poisoning.

Estimation of time to compromised tenability in fires: is it time to change paradigms?

The ISO standard 13571 estimates the time to the compromised tenability of people in enclosed fires. This is understood as the time which must be available for the structural design to pass an evacuation, or an escape paradigm for the evacuation of burning buildings. As with all emergency response planning values, such once-in-a-lifetime events cannot readily be validated side-by-side. Consequently, risk assessors must refer to animal-based reference data fitting the scenario of concern closely. The analysis detailed in this paper used the concentration × time (Cxt)-matrix of point of departures (PODs) from rats acutely exposed to carbon monoxide (CO), which is amongst the most abundant toxic fire gases. The objective of the analysis was to clarify whether the time- and effect-adjusted nonlethal threshold concentration LCt₀₁ × 1/3 from acute rat inhalation studies is suited to model thresholds characterizing any 'impairment of escape' in humans. Modeled outcomes are compared with published reference data from human volunteers exposed at the similar C × t's of CO at 800 ppm × 1-h and 100 ppm × 8-h. These exposure durations match the maximum escape duration of 1-h considered in the ISO standard 13571 and standards enforcing occupational exposure limits of 8-h duration. The reference PODs indicative of 'impairment of escape' in healthy adults relied on C × t's below those eliciting any loss of motor function or psychoneurological functions. The comparison of the LCt₀₁ × 1/3 based modeled outcomes from rats match favorably with the effect-based PODs from humans. Consistent with published evidence from humans, carboxyhemoglobin (COHb) saturation-a biomarker of exposure rather than of effect-failed to reliably predict effect-based outcomes. Unlike the LCt₀₁ × 1/3 threshold approach, the COHb-based median approach used by ISO TS 13571 is inconsistent with human evidence and both over- and under-estimates the CO-related potency for causing incapacitation at non-toxic and critically-toxic C × 's, respectively. In summary, it seems timely that the ISO TS 13571 standard pays attention to scientific progress in relevant toxicity information and refinements to scientific methods shown to adequately predict human risks.

Risk of Venous Thromboembolism After Carbon Monoxide Poisoning: A Nationwide Population-Based Study

STUDY OBJECTIVE

Few studies have investigated the association between carbon monoxide (CO) poisoning and risk of venous thromboembolism. We aim to identify the risk of pulmonary embolism and deep venous thrombosis after CO poisoning.

METHODS

We conducted a nationwide cohort-crossover study using administrative claims data in Korea. We compared the risk of venous thromboembolism (pulmonary embolism or deep venous thrombosis) in the cohort period after CO poisoning to that of the same period 1 year later (crossover period), using conditional logistic regression analysis.

RESULTS

We included 22,699 patients with a diagnosis of CO poisoning during the study period between 2004 and 2015. The risk of venous thromboembolism was significantly elevated during days 0 to 90 after CO poisoning (odds ratio 3.96; 95% confidence interval 2.50 to 6.25). However, this risk was not significantly elevated during subsequent postexposure periods through 360 days. During days 0 to 30 after CO poisoning, the risks of pulmonary embolism (odds ratio 22.00; 95% confidence interval 5.33 to 90.75) and deep venous thrombosis (odds ratio 10.33; 95% confidence interval 3.16 to 33.80) were significantly elevated.

CONCLUSION

We found that the risk of venous thromboembolism persisted for up to 90 days after CO poisoning. The risk was increased 22-fold for pulmonary embolism and 10-fold for deep venous thrombosis, especially in the first month after CO poisoning. Patients should be monitored for venous thromboembolism risk after CO poisoning.

The Diagnosis and Treatment of Carbon Monoxide Poisoning

BACKGROUND

The symptoms of carbon monoxide (CO) poisoning are nonspecific, ranging from dizziness and headache to unconsciousness and death. A German national guideline on the diagnosis and treatment of this condition is lacking at present.

METHODS

This review is based on a selective literature search in the PubMed and Cochrane databases, as well as on existing guidelines from abroad and expert recommendations on diagnosis and treatment.

RESULTS

The initiation of 100% oxygen breathing as early as possible is the most important treatment for carbon monoxide poisoning. In case of CO poisoning, the reduced oxygen-carrying capacity of the blood, impairment of the cellular respiratory chain, and immune-modulating processes can lead to tissue injury in the myocardium and brain even after lowering of the carboxyhemoglobin (COHb) concentration. In patients with severe carbon monoxide poisoning, an ECG should be obtained and biomarkers for cardiac ischemia should be measured. Hyperbaric oxygen therapy (HBOT) should be critically considered and initiated within six hours in patients with neurologic deficits, unconsciousness, cardiac ischemia, pregnancy, and/or a very high COHb concentration. At present, there is no general recommendation for HBOT, in view of the heterogeneous state of the evidence from multiple trials. Therapeutic decision-making is directed toward the avoidance of sequelae such as cognitive dysfunction and cardiac complications, and the reduction of mortality. Smoke intoxication must be considered in the differential diagnosis. The state of the evidence on the diagnosis and treatment of this condition is not entirely clear. Alternative or supplementary pharmacological treatments now exist only on an experimental basis.

CONCLUSION

High-quality, prospective, randomized trials that would enable a definitive judgment of the efficacy of HBOT are currently lacking.

Carbon monoxide poisoning in Denmark with focus on mortality and factors contributing to mortality

Introduction

Carbon monoxide (CO) poisoning is frequent worldwide but knowledge regarding the epidemiology is insufficient. The aim of this study was to clarify the extent of this intoxication, its mortality and factors associated with mortality.

Materials and methods

National databases from Statistics Denmark were used to identify individuals who suffered from CO-poisoning during 1995–2015, as well as information regarding co-morbidities, mortality and manner of death.

Results

During the period from 1995 to 2015, 22,930 patients suffered from CO-poisoning in Denmark, and 21,138 of these patients (92%) were hospitalized. A total of 2,102 patients died within the first 30 days after poisoning (9.2%). Among these, 1,792 (85% of 2,102) were declared dead at the scene and 310 (15% of 2,102) died during hospitalization. Deaths due to CO-poisoning from smoke were intentional in 6.3% of cases, whereas deaths due to CO containing gases were intentional in 98.0% of cases. Among patients who survived >30 days, there was no significant difference in survival when comparing hyperbaric oxygen therapy (HBO) treatment with no HBO treatment after adjustment for age and co-morbidities such as drug abuse, psychiatric disease, stroke, alcohol abuse, arterial embolism, chronic obstructive pulmonary disease, cerebrovascular disease and atrial fibrillation. Several co-morbidities predicted poorer outcomes for patients who survived the initial 30 days.

Conclusions

Poisoning from smoke and/or CO is a frequent incident in Denmark accounting for numerous contacts with hospitals and deaths. Both intoxication and mortality are highly associated with co-morbidities interfering with cognitive and physical function. Treatment with HBO was not seen to have an effect on survival.

Effects of ambient carbon monoxide on daily hospitalizations for cardiovascular disease: a time-stratified case-crossover study of 460,938 cases in Beijing, China from 2013 to 2017

BACKGROUND

Evidence focused on exposure to ambient carbon monoxide (CO) and the risk of hospitalizations for cardiovascular diseases (CVD) is lacking in developing countries. This study aimed to examine the effect of CO exposure on hospitalizations for CVD in Beijing, China.

METHODS

A total of 460,938 hospitalizations for cardiovascular diseases were obtained from electronic hospitalization summary reports from 2013 to 2017. A time-stratified case-crossover design was conducted to investigate the association between CO exposure and hospitalizations for total and cause-specific CVD, including coronary heart disease (CHD), atrial fibrillation (AF), and heart failure (HF). Stratified analysis was also conducted by age group (18-64 years and ≥ 65 years) and sex.

RESULTS

Linear exposure-response curves for the association between ambient CO exposure and hospitalizations for CVD was observed. Ambient CO was positively associated with hospitalizations for total CVD and CHD. However, the observed increased risk was not statistically significant for hospitalizations for AF and HF. The strongest effect of CO concentration was observed on the current- and previous-day of exposure (lag _0-1 day). For a 1 mg/m³ increase in a 2-day moving average CO concentration, an increase of 2.8% [95% confidence interval (CI): 2.2 to 3.3%] and 3.0% (95% CI: 2.4 to 3.6%) in daily hospital admissions for CVD and CHD were estimated, respectively. This association was robust after adjusting for other copollutants and did not vary by age group and sex.

CONCLUSIONS

Ambient CO exposure increased the risk of hospitalizations for CVD, especially for CHD in Beijing. Further studies are warranted to explore the association between ambient CO and hospitalizations for AF and HF.

ECMO improves survival following cardiogenic shock due to carbon monoxide poisoning - an experimental porcine model

Background

Severe intoxication with carbon monoxide (CO) is extremely lethal and causes numerous deaths due to cardiac or respiratory failure. Conventional intensive treatment may not be sufficient. The aim of this study was to investigate the treatment effect of extracorporeal veno-arterial extracorporeal membrane oxygenation (ECMO) following severe CO poisoning in an experimental porcine model.

Methods

A total of twelve pigs were anaesthetized, routinely monitored and intoxicated by inhalation of CO until the beginning of cardiac failure and randomized to a treatment (ventilator using an FiO₂ of 100% or ECMO). In the case of cardiac arrest, advanced resuscitation using standard guidelines was performed for at least 10 min. ECMO was also initiated in the ventilation group if the return of spontaneous circulation did not occur within 10 min. Lung tissue biopsies were obtained before and after CO intoxication.

Results

All animals in the ECMO group survived; however, one had to be resuscitated due to cardiac arrest. A single animal survived in the ventilator group, but five animals suffered from cardiac arrest at an average of 11.8 min after initiation of treatment. Conventional resuscitation failed in these animals, but four animals were successfully resuscitated after the establishment of ECMO.

A significant decrease was noticed in PO₂ with increasing HbCO, but there was no increase in pulmonary vascular resistance. No differences in H&E-stained lung tissue biopsies were observed.

Conclusions

The use of ECMO following severe CO poisoning greatly improved survival compared with conventional resuscitation in an experimental porcine model. This study forms the basis for further research among patients.

Epidemiological study on accidental poisonings in children from northeast romania

Accidental poisonongs are an important cause of morbidity and even mortality, especially in young children.We performed a retrospective observational study on a group of children admitted at the Regional Center of Toxicology at the Children's Emergency Hospital "St. Mary" Iasi with accidental intoxication within a period of 3 years. Data were collected from patients' files and processed with a SPPS 18.0 database and a 95% confidence interval.During this period, 480 children were admitted with accidental intoxication. Most of them were in the age group of 1 to 2 years (120 cases-24.3%). The etiology of these intoxications was dominated by nonmedication (67%), the most frequent being household chemicals, carbon monoxide, and insecticides. Accidental drug intoxication accounted for 33% of the cases, the main drugs involved being anticonvulsants, nonsteroidal anti-inflammatory drugs, and paracetamol. The mortality caused by accidental poisoning was 0.62%, all deaths owing to nonmedication intoxication.Identifying the epidemiological and evolutionary aspects of accidental intoxications must be a major objective for the health system, given that this pathology can be at least partially avoided and its incidence and severity may be reduced using appropriate measures.

Smokers' Views on Personal Carbon Monoxide Monitors, Associated Apps, and Their Use: An Interview and Think-Aloud Study

Smartphone-based personal carbon monoxide (CO) monitors and associated apps, or "CO Smartphone Systems" (CSSs) for short, could enable smokers to independently monitor their smoking and quitting. This study explored views and preferences regarding CSSs and their use among 16 adult, UK-based smokers. First, semi-structured interviews explored participants' expectations of CSSs. Secondly, a think-aloud study identified participants' reactions to a personal CO monitor and to existing or prototype apps. Framework Analysis identified five themes: (1) General views, needs, and motivation to use CSSs; (2) Views on the personal CO monitor; (3) Practicalities of CSS use; (4) Desired features in associated apps; and (5) Factors affecting preferences for CSSs and their use. Participants had high expectations of CSSs and their potential to increase motivation. Priority app features included: easy CO testing journeys, relevant and motivating feedback, and recording of contextual data. Appearance and usability of the personal CO monitor, and accuracy and relevance of CO testing were considered important for engagement. Participants differed in their motivation to use and preferences for CSSs features and use, which might have non-trivial impact on evaluation efforts. Personal CO monitors and associated apps may be attractive tools for smokers, but making CSSs easy to use and evaluating these among different groups of smokers may be challenging.

Ambient carbon monoxide and cardiovascular mortality: a nationwide time-series analysis in 272 cities in China

BACKGROUND

Evidence of the acute health effects of ambient carbon monoxide air pollution in developing countries is scarce and mixed. We aimed to evaluate short-term associations between carbon monoxide and daily cardiovascular disease mortality in China.

METHODS

We did a nationwide time-series analysis in 272 major cities in China from January, 2013, to December, 2015. We extracted daily cardiovascular disease mortality data from China's Disease Surveillance Points system. Data on daily carbon monoxide concentrations for each city were obtained from the National Urban Air Quality Real-time Publishing Platform. City-specific associations between carbon monoxide concentrations and daily mortality from cardiovascular disease, coronary heart disease, and stroke were estimated with over-dispersed generalised linear models. Bayesian hierarchical models were used to obtain national and regional average associations. Exposure-response association curves and potential effect modifiers were evaluated. Two-pollutant models were fit to evaluate the robustness of the effects of carbon monoxide on cardiovascular mortality.

FINDINGS

The average annual mean carbon monoxide concentration in these cities from 2013 to 2015 was 1·20 mg/m³, ranging from 0·43 mg/m³ to 2·45 mg/m³. For a 1 mg/m³ increase in average carbon monoxide concentrations on the present day and previous day (lag 0-1), we observed significant increments in mortality of 1·12% (95% posterior interval [PI] 0·42-1·83) from cardiovascular disease, 1·75% (0·85-2·66) from coronary heart disease, and 0·88% (0·07-1·69) from stroke. These associations did not vary substantially by city, region, and demographic characteristics (age, sex, and level of education), and the associations for cardiovascular disease and coronary heart disease were robust to the adjustment of criteria co-pollutants. We did not find a threshold below which carbon monoxide exposure had no effect on cardiovascular disease mortality.

INTERPRETATION

This analysis is, to our knowledge, the largest study done in a developing country, and provides robust evidence of the association between short-term exposure to ambient carbon monoxide and increased cardiovascular disease mortality, especially coronary heart disease mortality.

FUNDING

Public Welfare Research Program.

Air pollution and admissions due to ST elevation myocardial infarction-a time-series study from northwest of Iran

We investigated the association between the levels of air pollutants and the number of daily admissions due to ST segment elevation myocardial infarction (STEMI) in a metropolitan in the northwest of Iran. Daily concentrations of common air pollutants were obtained for the greater city of Tabriz for a period of 2 years. These reports included sulfur dioxide (SO2), nitrogen dioxide (NO2), nitric oxide (NO), nitrogen byproducts (NOx), carbon monoxide (CO), ozone (O3), and particulate matters < 10 μm (PM10). The census of admissions for STEMI was retrieved for the same period from hospital registries. The association of daily variations in air pollutant levels and the daily number of STEMI admissions were investigated in a time-series analysis. In the multi-pollutant model adjusting for long-term trend, seasonality, and temperature, a significant association was found for 1-h [NO2] and 24-h [CO]. A marginally significant association was observed for 24-h [NO2] and 8-h [CO]. The 24-h [CO] had the strongest association with the number of admissions with STEMI. Maximum 1-h concentrations of NO2 on the same day and on the prior day as well as 24-h concentrations of CO on the prior day were independently associated with increased number of STEMI admissions. However, daily concentrations of SO2, NO, O3, and PM10 were not associated with the frequency of hospital admissions for STEMI.

Increased long-term risk of major adverse cardiovascular events in patients with carbon monoxide poisoning: A population-based study in Taiwan

Background

Carbon monoxide (CO) poisoning may cause toxicity to the cardiovascular system. However, the association between CO poisoning and the risk of major adverse cardiovascular events (MACE) remains unestablished. We investigated the incidence of MACE after CO poisoning in Taiwan and evaluated whether CO-poisoned individuals had a higher risk of MACE than did the general population.

Methods

Using Taiwan’s National Health Insurance Research Database (NHIRD) during 2005–2013, a nationwide population-based cohort study was conducted among patients who experienced CO poisoning between 2005 and 2013. CO poisoning was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. The study cohort comprised patients with CO poisoning between 2005 and 2010 (N = 13,939). Each patient was matched according to age, sex and index date with four randomly selected controls from the comparison cohort (N = 55,756). All patients were followed from the study date until MACE development, death, or the end of 2013. The hazard ratios for MACE were compared between the two cohorts by using Cox proportional hazards regressions analyses.

Results

Incident cases of MACE were identified from the NHIRD. After adjustment for potential confounders, the study cohort was independently associated with a higher MACE risk (adjusted hazard ratio, 2.00; 95% confidence interval, 1.83–2.18).

Conclusion

This population-based cohort study indicated that patients with CO poisoning have a higher risk of MACE than do individuals without CO poisoning.

Risk Factors and Outcome Analysis in Children with Carbon Monoxide Poisoning

BACKGROUND

Carbon monoxide (CO) poisoning is one of the common causes of poisoning in patients and can result in significant morbidity and mortality. However, few studies have focused on the pediatric group.

METHODS

We retrospectively reviewed children (age < 18 years) with CO poisoning from nonfire accidents at a tertiary medical center in Taiwan from 2002 to 2010. We analyzed the patients' characteristics, management, and outcome; compared the data of patients who received hyperbaric oxygen (HBO) to those who received normobaric oxygen (NBO) therapy; and identified the ri0sk factors for patients who developed delayed neurological sequelae (DNS) or permanent neurological sequelae (PNS).

RESULTS

A total of 81 children were enrolled. The annual case number increased from five cases in 2002 to 20 in 2010, particularly during the cold months (December to February). The most common source of exposure was an indoor heating system (54.3%). The most common presenting symptoms were vomiting (32.1%) and consciousness changes (30.9%). HBO treatment tended to be administered to patients with a higher initial COHb (%) (p < 0.001), an initial Glasgow coma scale change (p < 0.001), and admission to the hospital (p = 0.002). After multivariate analysis, treatment in the intensive care unit because of prolonged loss of consciousness (p = 0.002) was the only independent risk factor for patients with DNS; only rescue by a ventilator (p < 0.001) was an independent risk factor for patients with PNS. In comparison to the NBO therapy, HBO treatment did not show benefit or harm to patients according to the incidence of inducing DNS or PNS after multivariate analysis.

CONCLUSION

For those with treatment in the intensive care unit because of prolonged loss of consciousness and rescue by a ventilator, special attention should be given and follow-up should be performed to determine whether DNS or PNS occurs, particularly epilepsy and cognitive deficits.

A review of AirQ Models and their applications for forecasting the air pollution health outcomes

Even though clean air is considered as a basic requirement for the maintenance of human health, air pollution continues to pose a significant health threat in developed and developing countries alike. Monitoring and modeling of classic and emerging pollutants is vital to our knowledge of health outcomes in exposed subjects and to our ability to predict them. The ability to anticipate and manage changes in atmospheric pollutant concentrations relies on an accurate representation of the chemical state of the atmosphere. The task of providing the best possible analysis of air pollution thus requires efficient computational tools enabling efficient integration of observational data into models. A number of air quality models have been developed and play an important role in air quality management. Even though a large number of air quality models have been discussed or applied, their heterogeneity makes it difficult to select one approach above the others. This paper provides a brief review on air quality models with respect to several aspects such as prediction of health effects.

Pentraxin 3, ischemia-modified albumin, and myeloperoxidase in predicting a cardiac damage in acute carbon monoxide poisoning

BACKGROUND

Carbon monoxide (CO) poisoning is associated with cardiac injuries or manifestations, frequently attributing to direct hypoxic damage at cellular level. For this, the aims were to evaluate the role of serum pentraxin 3 (PTX 3), ischemia-modified albumin (IMA), and myeloperoxidase (MPO) as an early biomarker for cardiac damage when compared to cardiac troponin I (cTnI) and creatine kinase-MB fraction (CK-MB) in adult patients with acute CO poisoning.

METHODS

Forty patients with acute CO poisoning admitted to the emergency department. The patients were divided into 2 main groups as follows: cardiac injury (group I, n=19) and nonsuspected cardiac injury (group II, n=21). Pentraxin 3, IMA, MPO, cTnI, CK-MB, and the other assays in the circulation were measured on admission.

RESULTS

Upon measuring the serum PTX 3, IMA, MPO, cTnI, and CK-MB levels as well as large electrocardiography and echocardiography abnormalities of patients with cardiac injury on admission, no statistical difference for PTX 3, IMA, and MPO was found between the groups (P>.05). However, cTnI, CK-MB, and leukocyte count (white blood cell) were higher determined in patients of group I compared to group II (P<.05). Receiver operating characteristic curve was also performed to evaluate the diagnostic performance of these tests in patients with cardiac injury.

CONCLUSIONS

Our results suggest that PTX, IMA, and MPO assays are not superior to cTnI and CK-MB in predicting a cardiac damage in patients with acute CO intoxication.

COHgb levels predict the long-term development of acute myocardial infarction in CO poisoning

BACKGROUND

There are several studies evaluating the cardiac effects of carbon monoxide (CO) poisoning during the acute period; however, the number of studies evaluating the long-term cardiac effects is limited.

OBJECTIVE

The present study aimed to evaluate the effects of blood carboxyhemoglobin (COHb) levels, elevated due to CO poisoning on the long-term development of acute myocardial infarction (AMI).

METHODS

This cross-sectional cohort study included a total of 1013 consecutive patients who presented to the emergency department (ED) due to CO poisoning, between January 2005 and December 2007. The diagnosis of CO poisoning was made according to the medical history and a COHb level of greater than 5%. In terms of AMI development, the patients were followed up for an average of 56 months.

RESULTS

At the end of follow-up, 100 (10%) of 1013 patients experienced AMI. Carboxyhemoglobin levels at the time of poisoning were higher among those who were diagnosed with AMI compared to those who were not (55%±6% vs 30%±7%; P<.001). Using a multivariate Cox proportional hazards model with forward stepwise method, age, COHb level, CO exposure time, and smoking remained associated with an increased risk of AMI after adjustment for the variables found to be statistically significant in a univariate analysis. According to a receiver operating characteristic curve analysis, the optimal cutoff value of COHb used to predict the development of AMI was found to be greater than 45%, with 98% sensitivity and 94.1% specificity.

CONCLUSION

In patients presenting to the ED with CO poisoning, COHb levels can be helpful for risk stratification in the long-term development of AMI.

Patients With Carbon Monoxide Poisoning and Subsequent Dementia: A Population-Based Cohort Study

The present study evaluated the dementia risk after carbon monoxide poisoning (CO poisoning). Using the National Health Insurance Research Database of Taiwan, a total of 9041 adults newly diagnosed with CO poisoning from 2000 to 2011 were identified as the CO poisoning cohort. Four-fold (N = 36,160) of non-CO poisoning insured people were randomly selected as controls, frequency-matched by age, sex, and hospitalization year. Incidence and hazard ratio (HR) of dementia were measured by the end 2011. The dementia incidence was 1.6-fold higher in the CO exposed cohort than in the non-exposed cohort (15.2 vs 9.76 per 10,000 person-years; n = 62 vs 174) with an adjusted HR of 1.50 (95% CI = 1.11-2.04). The sex- and age-specific hazards were higher in male patients (adjusted HR = 1.74, 95% CI = 1.20-2.54), and those aged <= 49 years (adjusted HR = 2.62, 95% CI = 1.38-4.99). CO exposed patients with 7-day or longer hospital stay had an adjusted HR of 2.18 (95% CI = 1.42, 3.36). The CO poisoning patients on hyperbaric oxygen (HBO2) therapy had an adjusted HR of 1.80 (95% CI = 0.96-3.37). This study suggests that CO poisoning may have association with the risk of developing dementia, which is significant for severe cases. The effectiveness of HBO2 therapy remains unclear in preventing dementia. Patients with CO poisoning are more prevalent with depression.

Risk of Coronary Artery Disease in Patients With Traumatic Intracranial Hemorrhage: A Nationwide, Population-Based Cohort Study

Traumatic intracranial hemorrhage (ICH) is prevalent worldwide with long-term consequences, including disabilities. However, studies on the association of traumatic ICH with coronary artery disease (CAD) are scant. Therefore, this study explored the aforementioned association in a large-scale, population-based cohort. A total of 128,997 patients with newly diagnosed traumatic ICH and 257,994 age- and sex-matched patients without traumatic ICH from 2000 to 2010 were identified from Taiwan's National Health Insurance Research Database. The Kaplan-Meier method was used for measuring the cumulative incidence of CAD in each cohort. Cox proportional regression models were used for evaluating the risk of CAD in patients with and without traumatic ICH and for comparing the risk between the 2 cohorts. The Kaplan-Meier analysis revealed that the cumulative incidence curves of CAD were significantly higher in patients with traumatic ICH than in those without ICH (log-rank test, P < 0.001). After adjustment for age, sex, and comorbidities, patients with traumatic ICH were associated with a higher risk of CAD compared with those without traumatic ICH (adjusted hazard ratio = 1.16, 95% confidence interval = 1.13-1.20). Compared with the general population, patients with traumatic ICH and having underlying comorbidities, including diabetes, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, chronic kidney disease, and congestive heart failure, exhibited multiplicative risks of developing CAD. This cohort study revealed an increased risk of CAD in patients with traumatic ICH. Therefore, comprehensive evaluation and aggressive risk reduction for CAD are recommended in these patients.

Risk of Peripheral Artery Disease in Patients With Carbon Monoxide Poisoning: A Population-Based Retrospective Cohort Study

Carbon monoxide (CO) poisoning can cause several life-threatening complications, particularly in cardiovascular and neurological systems. However, no studies have been performed to investigate the association between peripheral artery disease (PAD) and CO poisoning. We constructed a population-based retrospective cohort study to clarify the risks between PAD and CO poisoning. This population-based cohort study involved analyzing data from 1998 to 2010 obtained from the Taiwanese National Health Insurance Research Database, with a follow-up period extending to the end of 2011. We identified patients with CO poisoning and selected a comparison cohort that was frequency matched according to age, sex, and year of diagnosis of CO poisoning at a ratio of 1 patient to 4 control patients. We analyzed the risks for patients with CO poisoning and PAD by using Cox proportional hazards regression models. In this study, 9046 patients with CO poisoning and 36,183 controls were included. The overall risks for developing PAD were 1.85-fold in the patients with CO poisoning compared with the comparison cohort after adjusting for age, sex, and comorbidities. Our long-term cohort study results showed a higher risk for PAD development among patients with CO poisoning.

Inhaled matters of the heart

Inhalations of atmospheric pollutants, especially particulate matters, are known to cause severe cardiac effects and to exacerbate preexisting heart disease. Heart failure is an important sequellae of gaseous inhalation such as that of carbon monoxide. Similarly, other gases such as sulphur dioxide are known to cause detrimental cardiovascular events. However, mechanisms of these cardiac toxicities are so far unknown. Increased susceptibility of the heart to oxidative stress may play a role. Low levels of antioxidants in the heart as compared to other organs and high levels of reactive oxygen species produced due to the high energetic demand and metabolic rate in cardiac muscle are important in rendering this susceptibility. Acute inhalation of high concentrations of halogen gases is often fatal. Severe respiratory injury and distress occurs upon inhalation of halogens gases, such as chlorine and bromine; however, studies on their cardiac effects are scant. We have demonstrated that inhalation of high concentrations of halogen gases cause significant cardiac injury, dysfunction, and failure that can be critical in causing mortalities following exposures. Our studies also demonstrated that cardiac dysfunction occurs as a result of a direct insult independent of coexisting hypoxia, since it is not fully reversed by oxygen supplementation. Therefore, studies on offsite organ effects of inhaled toxic gases can impact development of treatment strategies upon accidental or deliberate exposures to these agents. Here we summarize the knowledge of cardiovascular effects of common inhaled toxic gases with the intent to highlight the importance of consideration of cardiac symptoms while treating the victims.

Increased risk of Parkinson disease in patients with carbon monoxide intoxication: a population-based cohort study

The present study evaluated the association of carbon monoxide intoxication (COI) with Parkinson disease (PD).A total of 9012 adults newly diagnosed with COI were enrolled in this study as the COI cohort. The control (non-COI) cohort, comprising 36,048 participants, was matched for each COI patient according to age, sex, and the year of hospitalization. We calculated the hazard ratios (HR) and 95% confidence intervals by using a Cox proportional hazards regression model.The overall incidence of PD (per 10,000 person-year) in the COI and non-COI cohorts was 27.4 and 2.53, respectively. After adjustment for age, sex, and comorbidities, the COI patients exhibited a 9.08-fold increased risk for PD. The COI patients without comorbidity exhibited a significantly higher risk of PD (adjusted HR = 15.8) than did the COI patients without comorbidity (adjusted HR = 4.15). Patients with COI and receiving hyperbaric oxygen therapy exhibited a 14.3-fold increased risk of PD; the adjusted HR of patients who did not receive hyperbaric oxygen treatment was increased 7.97-fold.The risk of PD increased in the COI patients and the significance increased in young people. COI is a crucial factor leading to PD.