Carbon monoxide poisoning and risk of deep vein thrombosis and pulmonary embolism: a nationwide retrospective cohort study

Incidence, timing, location, risk factors, and nomogram of lower extremity deep venous thrombosis after acute carbon monoxide poisoning

INTRODUCTION

Data on lower extremity deep venous thrombosis (DVT) following acute carbon monoxide (CO) poisoning are lacking. This study aimed to identify the incidence rate, timing, locations, risk factors, and nomogram of lower extremity DVT after acute CO poisoning.

METHODS

A total of 203 patients with acute CO poisoning from October 2019 to April 2021 were included in this retrospective study. Multivariate logistic regression analysis was performed to identify the independent risk factors associated with lower extremity DVT. Nomogram was drawn and area under the curve (AUC) was calculated to predict lower extremity DVT.

RESULTS

Overall, 14.3% (29/203) had lower extremity DVT, with incidence rates of 2.5% (5/203) for proximal DVT and 11.8% (24/203) for distal DVT. The lower extremity DVTs involved intermuscular vein in 28 patients, popliteal vein in 5 patients, and posterior tibial vein in 3 patients. The mean time from end of exposure to diagnosis of lower extremity DVT was 1.24 days. Among 29 lower extremity DVT cases, 6 (23.1%) DVT cases had thrombolysis. Multivariate logistic regression analysis revealed that long coma duration (P < 0.001) and high D-dimer levels (P < 0.001) were significantly associated with lower extremity DVT. The discrimination of nomogram was good with AUC of 0.93 (95% CI, 0.89-0.98).

CONCLUSION

Clinicians should be aware of and concerned with lower extremity DVT after acute CO poisoning, especially in patients with long coma duration and high D-dimer levels.

An artificial intelligence algorithm for analyzing globus pallidus necrosis after carbon monoxide intoxication

Globus pallidus necrosis (GPN) is one of typical neurological imaging features in patients with carbon monoxide (CO) poisoning. Current clinical guideline recommends neurological imaging examination for CO-intoxicated patients with conscious disturbance rather than routine screening, which may lead to undiagnosed GPN. We aimed to develop an artificial intelligence algorithm for predicting GPN in CO intoxication patients. We included CO intoxication patients with neurological images between 2000 and 2019 in Chang Gung Memorial Hospital. We collected 41 clinical and laboratory parameters on the first day of admission for algorithm development. We used fivefold cross validation and applied several machine learning algorithms. Random forest classifier (RFC) provided the best predictive performance in our cohort. Among the 261 patients with CO intoxication, 52 patients presented with GPN. The artificial intelligence algorithm using the RFC-based AI model achieved an accuracy = 79.2 ± 2.6%, sensitivity = 77.7%, precision score = 81.9 ± 3.4%, and F1 score = 73.2 ± 1.8%. The area under receiver operating characteristic was approximately 0.64. Top five weighted variables were Platelet count, carboxyhemoglobin, Glasgow Coma scale, creatinine, and hemoglobin. Our RFC-based algorithm is the first to predict GPN in patients with CO intoxication and provides fair predictive ability. Further studies are needed to validate our findings.

Air pollution increases the risk of pulmonary embolism: a meta-analysis

OBJECTIVES

Air pollution can lead to many cardiovascular and respiratory diseases, but the impact of air pollution on pulmonary embolism is still uncertain. We conducted a meta-analysis to assess the relationship between air pollution and pulmonary embolism.

CONTENT

We searched PubMed, EMBASE, Web of Science, and the Cochran Library for citations on air pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone and particulate matter) and pulmonary embolism. A total of nine citations met the inclusion criteria. There is no evidence of bias. CO, SO₂, PM₁₀ and PM_2.5 had no significant effect on the occurrence of pulmonary embolism. NO₂ and O₃ can increase the risk of pulmonary embolism to a small extent.

SUMMARY

This meta-analysis suggests that some air pollutants are associated with an increased risk of pulmonary embolism.

OUTLOOK

Reducing air pollution and improving air quality can effectively reduce the risk of pulmonary embolism.

The effect of emerging tobacco related products and their toxic constituents on thrombosis

Although conventional cigarette smoking is declining, emerging tobacco related products (ETRPs) are currently gaining ground, especially among the youth. These products include electronic cigarettes, waterpipes/hookah, cigars/cigarillo, smokeless tobacco, and heat-not-burn cigarettes. The observed increase in the use of ETRPs is multifactorial and complex but appears to be mainly driven by efforts from the major tobacco companies to reinvent themselves, and present more appealing and allegedly safe(r) tobacco products. However, it is becoming apparent that these products produce substantial amounts of toxic chemicals, many of which have been shown to exert negative health effects, including in the context of the cardiovascular system. Thus, there has been research efforts, albeit limited in general, to characterize the health impact of these products on occlusive/thrombotic cardiovascular diseases (CVD). In this review, we will discuss the potential impact of ETRPs on thrombosis-based CVD. Specifically, we will review how these products and the major chemicals they produce and/or emit can trigger key players in the process of thrombosis, namely inflammation, oxidative stress, platelets, coagulation, and the vascular endothelium, and the relationship between these effects.

Review on Disasters and Lower Limb Venous Disease

As per the World Health Organization, a disaster is defined as “an event that occurs in most cases suddenly and unexpectedly, causing severe disturbances to people or objects affected by it, resulting in the loss of life and harm to the health of the population.” A number of health issues are often reported following disasters, such as physical and psychological trauma, infections, malnutrition, and cardiovascular events. Among these, venous thromboembolism is deemed serious and thus should be taken into consideration. Indeed, its risk has been demonstrated to increase following earthquakes, floods, burns, and intoxications. The recent coronavirus pandemic summarizes some of the main triggering factors involved in acute and chronic venous disease development in a disaster setting: inflammation, infection, lockdown-induced reduced mobility, potential malnutrition, and overweight.

Proper venous risk assessment and guideline application have been determined to be essential in disaster management, particularly in the current time in which sheltering could lead to a potential exacerbation of the pandemic, which can only increase the risk for venous thrombotic diseases.

Global scientific teamwork is needed to make the recommendations as evidence-based and as homogeneous as possible among continents.

In this present review, we focus on how earthquakes impact venous thromboembolism, including an analysis of other disaster-related conditions, such as burns and intoxication. (This is a review article based on the informative seminar of the 40th Annual Meeting of Japanese Society of Phlebology.)

Risk factors for venous thromboembolism after carbon monoxide poisoning: A nationwide population-based study

Introduction:

The risk of venous thromboembolism increases after acute carbon monoxide poisoning. However, studies on the characteristics of patients who develop venous thromboembolism after carbon monoxide poisoning are rare. The aim of this study was to identify the risk factors for venous thromboembolism within 3 months after carbon monoxide poisoning.

Methods:

This is a population-based study that employed nationwide claims data from South Korea. Among the carbon monoxide poisoning patients (⩾18 years), the characteristics of the groups with and without venous thromboembolism (pulmonary embolism or deep vein thrombosis) were identified. All the significant variables in the univariable analysis were included in the multivariable logistic regression to determine the risk factors for venous thromboembolism occurrence.

Results:

Among the 24,232 carbon monoxide poisoning patients, 130 subjects developed venous thromboembolism within 90 days of their carbon monoxide poisoning diagnosis. The significant risk factors for venous thromboembolism in the multivariable analysis were age (adjusted odds ratio (aOR) = 1.01; 95% confidence interval (CI) = 1.003–1.03), intensive care unit admission (aOR = 3.80; 95% CI = 2.34–6.12), length of stay (aOR = 1.02; 95% CI = 1.0001–1.04), congestive heart failure (aOR = 2.17; 95% CI = 1.36–3.42), and cancer (aOR = 1.94; 95% CI = 1.10–3.22). The adjusted odds ratios for intensive care unit admission for patients with pulmonary embolism and deep vein thrombosis were 3.05 (95% CI = 1.61–5.61) and 5.60 (95% CI = 2.89–10.90), respectively.

Conclusion:

Patients with older age, intensive care unit admission, a longer length of stay, congestive heart failure, or cancer are at greater risk of developing venous thromboembolism after carbon monoxide poisoning. In particular, intensive care unit admission was the strongest risk factor for venous thromboembolism, pulmonary embolism, and deep vein thrombosis. Monitoring and administering prophylactic treatments to prevent venous thromboembolism would be helpful in high-risk in carbon monoxide poisoning patients.

Air pollution and hospital admissions due to deep vein thrombosis (DVT) in Ahvaz, Iran

There are limited studies on the relation between short-term exposure to air pollutants and the risk of deep venous thrombosis (DVT). The aim of this study was to determine the relation between the concentration of these pollutants and the risk of hospital admissions due to DVT in Ahvaz, which is one of the world's highly polluted cities. Daily data on pollutants including O₃, NO, NO₂, SO₂, CO, PM₁₀, and PM_2.5and DVT hospital admissions were collected from2008until 2018. Quasi-Poisson regression combined with linear distributed lag models; adjusted for trend, seasonality, temperature, relative humidity, weekdays, and holidays were used to assess the relation between the daily average of air pollutants and hospital admission for DVT. The results showed that there was a significant increase in hospital admissions due to DVT in the total, men, women, and elderly populations in relation to NO and NO₂. There was also a significant increase in DVT hospital admissions in the male and ≤60 years populations related to PM₁₀; and among the female and ≤60 years old populations, related to PM_2.5. Finally, the results showed that there were significant positive associations between SO2 and CO exposure and the incidence of DVT hospital admissions among men and women, respectively. The results of this study show the possible effect of short-term exposure to air pollution on the risk of DVT. Further studies are required to investigate whether direct interventions through industry and government policy may alter the impact of specific pollutants in order to alter the incidence of DVT and other identified health complications.

Relationships between hyperinsulinaemia, magnesium, vitamin D, thrombosis and COVID-19: rationale for clinical management

Risk factors for COVID-19 patients with poorer outcomes include pre-existing conditions: obesity, type 2 diabetes mellitus, cardiovascular disease (CVD), heart failure, hypertension, low oxygen saturation capacity, cancer, elevated: ferritin, C reactive protein (CRP) and D-dimer. A common denominator, hyperinsulinaemia, provides a plausible mechanism of action, underlying CVD, hypertension and strokes, all conditions typified with thrombi. The underlying science provides a theoretical management algorithm for the frontline practitioners.Vitamin D activation requires magnesium. Hyperinsulinaemia promotes: magnesium depletion via increased renal excretion, reduced intracellular levels, lowers vitamin D status via sequestration into adipocytes and hydroxylation activation inhibition. Hyperinsulinaemia mediates thrombi development via: fibrinolysis inhibition, anticoagulation production dysregulation, increasing reactive oxygen species, decreased antioxidant capacity via nicotinamide adenine dinucleotide depletion, haem oxidation and catabolism, producing carbon monoxide, increasing deep vein thrombosis risk and pulmonary emboli. Increased haem-synthesis demand upregulates carbon dioxide production, decreasing oxygen saturation capacity. Hyperinsulinaemia decreases cholesterol sulfurylation to cholesterol sulfate, as low vitamin D regulation due to magnesium depletion and/or vitamin D sequestration and/or diminished activation capacity decreases sulfotransferase enzyme SULT2B1b activity, consequently decreasing plasma membrane negative charge between red blood cells, platelets and endothelial cells, thus increasing agglutination and thrombosis.Patients with COVID-19 admitted with hyperglycaemia and/or hyperinsulinaemia should be placed on a restricted refined carbohydrate diet, with limited use of intravenous dextrose solutions. Degree/level of restriction is determined by serial testing of blood glucose, insulin and ketones. Supplemental magnesium, vitamin D and zinc should be administered. By implementing refined carbohydrate restriction, three primary risk factors, hyperinsulinaemia, hyperglycaemia and hypertension, that increase inflammation, coagulation and thrombosis risk are rapidly managed.

Whether productive authors using the national health insurance database also achieve higher individual research metrics: A bibliometric study

BACKGROUND

Many researchers use the National Health Insurance Research Database (HIRD) to publish medical papers and gain exceptional outputs in academics. Whether they also obtain excellent citation metrics remains unclear.

METHODS

We searched the PubMed database (http://www.ncbi.nlm.nih.gov/pubmed) using the terms Taiwan and HIRD. We then downloaded 1997 articles published from 2012 to 2016. An authorship-weighted scheme (AWS) was applied to compute coauthor partial contributions from the article bylines. Both modified x-index and author impact factor (AIF) proved complementary to Hirsch's h-index for calculating individual research achievements (IRA). The metrics from 4684 authors were collected for comparison. Three hundred eligible authors with higher x-indexes were located and displayed on Google Maps dashboards. Ten separate clusters were identified using social network analysis (SNA) to highlight the research teams. The bootstrapping method was used to examine the differences in metrics among author clusters. The Kano model was applied to classify author IRAs into 3 parts.

RESULTS

The most productive author was Investigator#1 (Taichung City, Taiwan), who published 149 articles in 2015 and included 803 other members in his research teams. The Kano diagram results did not support his citation metrics beyond other clusters and individuals in IRAs.

CONCLUSION

The AWS-based bibliometric metrics make individual weighted research evaluations possible and available for comparison. The study results of productive authors using HIRD did not support the view that higher citation metrics exist in specific disciplines.

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.

Intracardiac Thrombosis and Multiple Arterial Thromboembolism with Acute Limb Ischemia: A Rare Complication of Carbon Monoxide Intoxication

Carbon monoxide (CO) poisoning is a very common reason for emergency ward admission, with symptoms varying from a simple headache and dizziness to severe neurological and cardiac impairment. We report here a rare clinical presentation of CO intoxication manifested by a severe cardiac impairment with intracardiac thrombus formation, acute limb ischemia, renal infarction, and carotid artery thrombosis. There have been initial reports of thromboembolic events in acute CO poisoning with intracardiac thrombosis being sparsely reported. Contrary to venous thromboembolism, arterial thromboembolism in CO poisoning seems to be extremely rare. To the best of our knowledge, this is the first report in recent literature of a combined intracardiac thrombosis and multiple arterial thromboembolism induced by CO poisoning.

Life-Threatening Acute Pulmonary Thromboembolism Following Severe Carbon Monoxide Poisoning

A 57-year-old man admitted with severe carbon monoxide (CO) poisoning suffered life-threatening pulmonary embolism (PE) after hyperbaric oxygen therapy, in the absence of other risk factors for thromboembolism, and was successfully treated with thrombolysis. CO is a thrombophilic condition predisposing to PE and active surveillance is advisable. (Level of Difficulty: Advanced.)

Understanding the productive author who published papers in medicine using National Health Insurance Database: A systematic review and meta-analysis

Many researchers used National Health Insurance database to publish medical papers which are often retrospective, population-based, and cohort studies. However, the author's research domain and academic characteristics are still unclear.By searching the PubMed database (Pubmed.com), we used the keyword of [Taiwan] and [National Health Insurance Research Database], then downloaded 2913 articles published from 1995 to 2017. Social network analysis (SNA), Gini coefficient, and Google Maps were applied to gather these data for visualizing: the most productive author; the pattern of coauthor collaboration teams; and the author's research domain denoted by abstract keywords and Pubmed MESH (medical subject heading) terms.Utilizing the 2913 papers from Taiwan's National Health Insurance database, we chose the top 10 research teams shown on Google Maps and analyzed one author (Dr. Kao) who published 149 papers in the database in 2015. In the past 15 years, we found Dr. Kao had 2987 connections with other coauthors from 13 research teams. The cooccurrence abstract keywords with the highest frequency are cohort study and National Health Insurance Research Database. The most coexistent MESH terms are tomography, X-ray computed, and positron-emission tomography. The strength of the author research distinct domain is very low (Gini < 0.40).SNA incorporated with Google Maps and Gini coefficient provides insight into the relationships between entities. The results obtained in this study can be applied for a comprehensive understanding of other productive authors in the field of academics.

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 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.

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.