Neurocognitive sequelae after carbon monoxide poisoning and hyperbaric oxygen therapy

Hyperbaric oxygen therapy for paroxysmal sympathetic hyperactivity syndrome after brain injury: a multicenter, retrospective cohort study

Hyperbaric oxygen has been used to treat many diseases. However, there are few reports on hyperbaric oxygen treatment for paroxysmal sympathetic hyperactivity at home and abroad, and the clinical experience is very limited. To understand the efficacy of hyperbaric oxygen treatment for paroxysmal sympathetic hyperactivity after brain injury, this retrospective study was conducted in the adult intensive care units of five medical centers in central China. Ninety-two patients with paroxysmal sympathetic hyperactivity syndrome after brain injury were selected from January 2021 to September 2023. Fifty-six patients treated with hyperbaric oxygen were included in the hyperbaric oxygen group, and 36 patients without hyperbaric oxygen treatment were included in the control group. Patients in the hyperbaric oxygen group received 3-5 courses of hyperbaric oxygen treatment, twice daily, once for 70 minutes, 10 days for 1 course of treatment. Compared with before hyperbaric oxygen treatment, the paroxysmal sympathetic hyperactivity symptoms of all patients were significantly relieved after three courses of hyperbaric oxygen treatment. Compared with those in the control group, patients in the hyperbaric oxygen group had higher Glasgow coma scale scores, lower paroxysmal sympathetic hyperactivity syndrome assessment measure scores, and shorter intensive care unit stays. In conclusion, the use of hyperbaric oxygen therapy as an assisted therapy can significantly alleviate the symptoms of patients with paroxysmal sympathetic hyperactivity, thereby providing new ideas for the treatment of paroxysmal sympathetic hyperactivity.

Burden of Carbon Monoxide Poisoning in Asian Countries From 1990 to 2021 and Its Projection Until 2030: An Analysis of the Global Burden of Disease Study 2021

Background

Carbon monoxide (CO) poisoning represents a significant contributor to injury burden across Asia. This study seeks to assess the burden of CO poisoning in Asia from 1990 to 2021 utilizing data from the Global Burden of Disease Study (GBD) 2021.

Methods

Data on the burden of CO poisoning across 49 Asian countries were extracted from GBD 2021. The variations in burden were analyzed according to year, gender, location, age, and Socio-Demographic Index (SDI). Analyses included Joinpoint analysis to evaluate temporal trends, the age-period-cohort model to assess disease burden trends, the slope index of inequality and concentration index for assessing health disparities, frontier analysis for estimating potential outcomes based on developmental stages, and the auto-regressive integrated moving average model to predict the disability-adjusted life year (DALY) rates.

Results

During 1990-2021, the age-standardized incidence rate (average annual percent change (AAPC) = -0.83, 95% CI: -0.94 to -0.73), age-standardized mortality rate (AAPC = -2.01, 95% CI: -2.20 to -1.81), and DALY rates (AAPC = -2.39, 95% CI: -2.54 to -2.23) for CO poisoning across Asia declined. In 2021, females experienced a lower burden than males, and countries in higher latitudes bore a greater burden. The burden was more pronounced in extreme age groups, with an elevated cohort risk in the 1967-1971 birth cohort (relative risk (RR) = 1.045, 95% CI: 0.96-1.14). Health inequality analyses showed a reduction in disparities between countries with varying SDI levels. Frontier analysis identified potential improvements in reducing the burden across different countries. However, there was no notable correlation between this burden and SDI levels. The age-standardized disability-adjusted life year rate is predicted to continue declining from 2022 to 2030.

Conclusion

This study analyzes the burden of CO poisoning in Asia, revealing a decline from 1990 to 2021, with variations across countries and higher burdens in males and extreme age groups. It suggests a reduction in health inequalities and forecasts a continued decline in the burden by 2030.

Carbon monoxide poisoning is associated with increased risk of migraine in the long term: a nationwide population-based cohort study

Objective

Carbon monoxide poisoning can cause migraine-like attacks. However, the association between carbon monoxide poisoning and the risk of migraine has not been thoroughly studied. This study aimed to investigate the long-term risk of migraine in patients with carbon monoxide poisoning.

Methods

This nationwide, population-based cohort study was conducted using the administrative database of the National Health Insurance Service of Korea from 2002 to 2021. Patients with carbon monoxide poisoning with at least one visit documented according to the International Classification of Diseases, 10th Revision code T58 were included. Patients were only included if they had the same diagnostic code at two or more outpatient clinic visits. The primary outcome of this study was the incidence of migraine after carbon monoxide poisoning.

Results

The overall risk of migraine was higher in the carbon monoxide poisoning group regardless of age, sex, or use of hyperbaric oxygen therapy (adjusted hazard ratio, 1.37; 95% confidence interval, 1.28-1.48). The carbon monoxide poisoning group had a persistently higher cumulative incidence of migraine during the observation period than the control group.

Conclusion

Carbon monoxide poisoning was associated with an increased overall risk of developing migraine during long-term follow-up.

Carbon monoxide poisoning is associated with an increased risk of epilepsy and status epilepticus: a nationwide population-based cohort study conducted in the Republic of Korea between 2002-2021

INTRODUCTION

Carbon monoxide poisoning may result in various neurological injuries, including acute symptomatic seizures. We aimed to investigate the long-term risk of epilepsy and status epilepticus in patients with previous carbon monoxide poisoning.

METHODS

The study population was derived from the National Health Insurance Service database of the Republic of Korea between 1 January 2002 and 31 December 2021. We included adults with at least one documented visit to medical facilities because of carbon monoxide poisoning (International Classification of Diseases, Tenth Revision, code T58). Patients were matched, on the same index date, with controls, without a T58 code, for age, sex, insurance type, income level, and residence location in a 1:1 ratio. Follow-up continued until death, migration, or the end of the observation period (31 December 2021). The primary outcome was the incidence of epilepsy (codes G40 or R56) and status epilepticus (code G41).

RESULTS

This study included 53,380 patients with carbon monoxide poisoning and 53,380 controls, with 44.2% women and a mean age of 45.7 years. The mean (±SD) follow-up period was 5.7 ± 4.3 years in the carbon monoxide poisoned group and 6.4 ± 4.4 years in controls. The overall risk of epilepsy (adjusted hazard ratio 2.60; 95% CI: 2.43-2.78; P < 0.001) and status epilepticus (adjusted hazard ratio 4.10; 95% CI: 2.84-5.92; P < 0.001) was significantly increased in the carbon monoxide poisoned group compared to controls. The risk of epilepsy and status epilepticus was increased in patients with previous carbon monoxide poisoning, regardless of sex, age or a history of stroke, neurodegenerative diseases, or central nervous system tumour or infection. However, in the subgroup analysis according to age, the highest risk of epilepsy and status epilepticus was observed in patients less than 40 years of age.

DISCUSSION

In this population-based cohort study, previous carbon monoxide poisoning was associated with an increased risk of epilepsy and status epilepticus. The risk was more noticeable in patients aged less than 40 years. Further studies are needed to confirm such an association in other populations.

CONCLUSIONS

Previous carbon monoxide poisoning was associated with an increased risk of epilepsy and status epilepticus, particularly in the younger population. The long-term management of survivors of carbon monoxide poisoning should include monitoring for epilepsy and status epilepticus.

Association between serum neuron-specific enolase at admission and the risk of delayed neuropsychiatric sequelae in adults with carbon monoxide poisoning: A meta-analysis

Delayed neuropsychiatric sequelae (DNS) significantly impact the quality of life in patients following acute carbon monoxide poisoning (COP). This systematic review and meta-analysis aimed to assess the relationship between serum neuron-specific enolase (NSE) levels at admission and the risk of DNS in adults after acute COP. Relevant observational studies with longitudinal follow-up were identified through searches in PubMed, Embase, Web of Science, Wanfang, and China National Knowledge Infrastructure databases. The random-effects model was used to aggregate results, accounting for potential heterogeneity. Nine cohort studies, including 1501 patients, were analyzed, with 254 (16.9%) developing DNS during follow-up. The pooled data indicated that elevated serum NSE in the early phase was linked to a higher risk of subsequent DNS (odds ratio per 1 ng/mL increase in NSE: 1.10, 95% confidence interval: 1.06 to 1.15, P < 0.001). Moderate heterogeneity (I2 = 46%) among the studies was entirely attributed to one study with the longest follow-up duration (22.3 months; I2 = 0% after excluding this study). Subgroup analyses based on country, study design, sample size, age, sex, admission carboxyhemoglobin levels, DNS incidence, follow-up duration, and quality score yielded consistent results (P for subgroup differences all > 0.05). In summary, high serum NSE levels in the early phase of acute COP are associated with an increased risk of developing DNS during follow-up.

Carbon Monoxide-Related Vision Loss in an Acute Burn Patient

Carbon monoxide poisoning can occur as part of smoke exposure in the burn population. Here we report the case of a 32-year-old, previously healthy male, with carbon monoxide-related blindness after smoke exposure in an apartment fire. Cerebral hypoperfusion was diagnosed using magnetic resonance imaging of the brain, and the patient was diagnosed with cortical visual impairment. He was treated with hyperbaric oxygen therapy following which he had partial recovery of his vision. There is a paucity of information regarding this phenomenon and its treatment.

Edaravone combined with hyperbaric oxygen therapy in delayed encephalopathy after acute carbon monoxide poisoning: A meta-analysis

BACKGROUND

The use of both edaravone (EDA) and hyperbaric oxygen therapy (HBOT) is increasingly prevalent in the treatment of delayed encephalopathy after carbon monoxide poisoning (DEACMP). This meta-analysis aims to evaluate the efficacy of using EDA and HBOT in combination with HBOT alone in the treatment of DEACMP.

METHODS

We searched and included all randomized controlled trials (RCTs) published before November 6, 2023, from 12 Chinese and English databases and clinical trial centers in China and the United States. The main outcome indicator was the total effective rate. The secondary outcome indicators included the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), National Institutes of Health Stroke Scale (NIHSS), Barthel Index (BI), Hasegawa Dementia Scale (HDS), Fugl-Meyer Assessment (FMA), Superoxide Dismutase (SOD), and Malondialdehyde (MDA). Statistical measures utilized include risk ratios (RR), weighted mean difference (WMD), and 95 % confidence intervals (95 % CI).

RESULTS

Thirty studies involving a combined total of 2075 participants were ultimately incorporated. It was observed that the combination of EDA with HBOT for the treatment of DEACMP demonstrated an improvement in the total effective rate (RR: 1.25; 95 % CI: 1.20-1.31; P < 0.01), MMSE (WMD: 3.67; 95 % CI: 2.59-4.76; P < 0.01), MoCA (WMD: 4.38; 95 % CI: 4.00-4.76; P < 0.01), BI (WMD: 10.94; 95 % CI: 5.23-16.66; P < 0.01), HDS (WMD: 6.80; 95 % CI: 4.05-9.55; P < 0.01), FMA (WMD: 8.91; 95 % CI: 7.22-10.60; P < 0.01), SOD (WMD: 18.45; 95 % CI: 16.93-19.98; P < 0.01); and a reduction in NIHSS (WMD: -4.12; 95 % CI: -4.93 to -3.30; P < 0.01) and MDA (WMD: -3.05; 95 % CI: -3.43 to -2.68; P < 0.01).

CONCLUSION

Low-quality evidence suggests that for DEACMP, compared to using HBOT alone, the combined use of EDA and HBOT may be associated with better cognition and activity of daily living. In the future, conducting more meticulously designed multicenter and large-sample RCTs to substantiate our conclusions is essential.

Carbon monoxide poisoning and phototherapy

Carbon monoxide (CO) poisoning is a leading cause of poison-related morbidity and mortality worldwide. By binding to hemoglobin and other heme-containing proteins, CO reduces oxygen delivery and produces tissue damage. Prompt treatment of CO-poisoned patients is necessary to prevent acute and long-term complications. Oxygen therapy is the only available treatment. Visible light has been shown to selectively dissociate CO from hemoglobin with high efficiency without affecting oxygen affinity. Pulmonary phototherapy has been shown to accelerate the rate of CO elimination in CO poisoned mice and rats when applied directly to the lungs or via intra-esophageal or intra-pleural optical fibers. The extracorporeal removal of CO using a membrane oxygenator with optimal characteristic for blood exposure to light has been shown to accelerate the rate of CO illumination in rats with or without lung injury and in pigs. The development of non-invasive techniques to apply pulmonary phototherapy and the development of a compact, highly efficient membrane oxygenator for the extracorporeal removal of CO in humans may provide a significant advance in the treatment of CO poisoning.

The effect of preconditioning agents on cardiotoxicity and neurotoxicity of carbon monoxide poisoning in animal studies: a systematic review

BACKGROUND

Carbon monoxide (CO) poisoning is a common intoxication and many people die yearly due to CO poisoning and preconditioning agents attenuate brain and cardiac injury caused by intoxication. It is critical to fully understand the efficacy of new methods to directly target the toxic effect of CO, such as conditioning agents, which are currently under development. This study aims to systematically investigate current evidence from animal experiments and the effects of administration preconditions in acute and late phases after CO poisoning on cardiotoxicity and neurotoxicity.

METHODS

Four databases (PubMed, Embase, Scopus, and Web of Science) were systematically searched without language restrictions, and hand searching was conducted until November 2021. We included studies that compare preconditioning agents with the control group after CO poisoning in animals. The SYRCLE RoB tool was used for risk of bias assessments.

RESULTS

Thirty-seven studies were included in the study. Erythropoietin, granulocyte colony-stimulating factor (GCSF), hydrogen-rich saline, and N-butylphthalide (NBP) were found to have positive effects on reducing neurotoxicity and cardiotoxicity. As other preconditions have fewer studies, no valuable results can be deduced. Most of the studies were unclear for sources of bias.

DISCUSSION

Administration of the examined preconditioning agents including NBP, hydrogen-rich saline, and GCSF in acute and late phases could attenuate neurotoxicity and cardiotoxicity of CO poisoned animals. For a better understanding of mechanisms and activities, and finding new and effective preconditioning agents, further preclinical and clinical studies should be performed to analyze the effects of preconditioning agents.

Imaging of glutamate in acute carbon monoxide poisoning using chemical exchange saturation transfer

Aims

This study adopted the Glutamate Chemical Exchange Saturation Transfer (GluCEST) imaging technique to quantitatively analyze cranial glutamate and discussed the effectiveness of GluCEST values in identifying the pathogenesis of encephalopathy after CO poisoning.

Methods

The routine MRI and functional MRI scans of two cohorts of subjects (CO group, n = 29; Control group, n = 21) were performed. Between-group comparisons were conducted for GluCEST% in regions of interest (ROI), including the basal ganglia, the thalamus, the frontal lobe, the occipital lobe, the genu of corpus callosum, the cingulate gyrus, and the cuneus. Moreover, an age-stratified subgroup analysis was devised, and a correlational analysis was performed for GluCEST% in each ROI, including the time in coma, Simple Mini-Mental State Examination Scale (MMSE) score, Hamilton Anxiety Scale score, and blood COHb%.

Results

As compared to the healthy control, the CO group led to significantly increasing GluCEST% in the basal ganglia, the occipital lobe, the genu of the corpus callosum, the cingulate gyrus, and the cuneus (p < 0.05). In the subgroup analysis for age, adult patients had higher GluCEST% in the basal ganglia, the thalamus, the occipital lobe, the cingulate gyrus, and the cuneus compared to healthy adults (p < 0.05). In addition, the correlational analysis of CO-poisoned patients revealed a statistical association between the GluCEST% and the MMSE in the thalamus and the genu of the corpus callosum.

Conclusion

The GluCEST technique is superior to routine MRI in that it can identify the cerebral biochemical changes sooner after acute CO poisoning, which is significant for our understanding of the role of neurotransmitters in the pathological basis of this disease. Brain injury caused by CO poisoning may be different in adults and children.

Hyperbaric oxygen therapy in carbon monoxide poisoning in Moroccan patients

Describe the epidemiological, clinical characteristics of acute carbon monoxide poisoning (COP), and the therapeutic effect of hyperbaric oxygen therapy on patient's clinical outcome. This is the first study in this field in Morocco. It studies retrospectively 309 victims of acute COP with major neurological signs. All patients have been treated with hyperbaric oxygen therapy, and have been admitted by the emergency department of the Mohammed V military training hospital in Rabat, between January 2015 and December 2018. All poisonings were accidental and occurred especially in winter (50%), with a predominance in urban areas (93%). The poisoning was often caused by a non-compliant water heater (91%), multi-causality was in half of the cases, and affected adults and women (mean age: 21 ± 17 years, gender (male:female) 1:1.5. The average admission time to the hyperbaric chamber lasted 9 h 04 min (± 12 h 32 min). Clinical signs were mainly unconsciousness (151 cases), headache (85 cases), vomiting (63 cases), nausea (53 cases), and dizziness (51 cases). All the patients benefitted from hyperbaric oxygen therapy sessions. The clinical outcome was positive in the majority of cases, but 23% of the cases presented minor or major sequelae. Patients with sequelae had a longer length of admission than those who had not. COP is a major public health problem in Morocco. Through this study, we suggest the interest of hyperbaric oxygen therapy, especially when it is administered timely without delay.

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.

Delayed Neurological Sequelae Successfully Treated with Adjuvant, Prolonged Hyperbaric Oxygen Therapy: Review and Case Report

Carbon Monoxide (CO) intoxication is still a leading cause of mortality and morbidity in many countries. Due to the problematic detection in the environment and subtle symptoms, CO intoxication usually goes unrecognized, and both normobaric and hyperbaric oxygen (HBO) treatments are frequently administered with delay. Current knowledge is mainly focused on acute intoxication, while Delayed Neurological Sequelae (DNS) are neglected, especially their treatment. This work details the cases of two patients presenting a few weeks after CO intoxication with severe neurological impairment and a characteristic diffused demyelination at the brain magnetic resonance imaging, posing the diagnosis of DNS. After prolonged treatment with hyperbaric oxygen, combined with intravenous corticosteroids and rehabilitation, the clinical and radiological features of DNS disappeared, and the patients' neurological status returned to normal. Such rare cases should reinforce a thorough clinical follow-up for CO intoxication victims and promote high-quality studies.

Acute carbon monoxide poisoning in Shandong, China: an observational study

Background

Carbon monoxide (CO) poisoning remains a major cause of accidental injuries and multiple studies have indicated that CO is also associated with significantly severe or long-term toxicity to the central nervous system. Given that CO poisoning causes serious morbidity and mortality, a better understanding of epidemiological features and clinical characteristics of acute CO poisoning in China is crucial.

Methods

We collected the clinical data of acute CO poisoning in patients between November 2019 and April 2020 across Shandong province, China and analyzed its characteristics focusing on the weekly amount and the severity of the confirmed cases.

Results

A total number of 21,088 acute CO poisoning cases were diagnosed. The overall incidence of acute CO poisoning was approximately 0.021%. On severity rankings, 63% of confirmed cases (n = 13,378) were mild, 27% (n = 5635) were moderate, and 10% (n = 2075) were severe. Interestingly, the coastal cities had more confirmed cases than the inland/suburban areas in Shandong. Meanwhile, the number of confirmed cases was negatively correlated with the local mean daily temperature (P = 0.0167).

Conclusions

Mild acute CO poisoning cases accounted for the majority of all confirmed cases during the winter of 2019. In Shandong province, which is located in east China, residents of the coastal cities are more susceptible to CO poisoning than residents of inland cities.

Carbon monoxide-triggered health effects: the important role of the inflammasome and its possible crosstalk with autophagy and exosomes

Carbon monoxide (CO) has long been known as a "silent killer" because of its ability to bind hemoglobin (Hb), leading to reduced oxygen carrying capacity of Hb, which is the main cause of CO poisoning (COP) in humans. Emerging studies suggest that mitochondria is a key target of CO action that can impact key biological processes, including apoptosis, cellular proliferation, inflammation, and autophagy. Despite its toxicity at high concentrations, CO also exhibits cyto- and tissue-protective effects at low concentrations in animal models of organ injury and disease. Specifically, CO modulates the production of pro- or anti-inflammatory cytokines and mediators by regulating the NLRP3 inflammasome. Given that human diseases are strongly associated with inflammation, a deep understanding of the exact mechanism is helpful for treatment. Autophagic factors and inflammasomes interact in various situations, including inflammatory disease, and exosomes might function as the bridge between the inflammasome and autophagy activation. Thus, the interplay among autophagy, mitochondrial dysfunction, exosomes, and the inflammasome may play pivotal roles in the health effects of CO. In this review, we summarize the latest research on the beneficial and toxic effects of CO and their underlying mechanisms, focusing on the important role of the inflammasome and its possible crosstalk with autophagy and exosomes. This knowledge may lead to the development of new therapies for inflammation-related diseases and is essential for the development of new therapeutic strategies and biomarkers of COP.

The occurrence of delayed neuropsychologic sequelae in acute carbon monoxide poisoning patients after treatment with hyperbaric or normobaric oxygen therapy

This study aimed at assessing which one of the 2 therapies is better for treating carbon monoxide (CO) poisoning from the perspective of reducing delayed neuropsychologic sequelae (DNS).We used Taiwan's National Health Insurance Research Database (NHIRD) to conduct a nationwide population-based cohort study to assess which therapy is better for CO poisoning patients. To accurately identify patients with DNS, the definition of DNS is included neurological sequelae, and cognitive and psychological sequele. The independent variable was therapy and the dependent variable was DNS occurred within 1 year after discharge from a medical institution. The control variables were age, gender, the severity of CO poisoning, and comorbidities present before CO poisoning admission.The risk of developing DNS in patients treated with Hyperbaric Oxygen (HBO) was 1.87-fold (P < .001) than normobaric oxygen (NBO) therapy. The severity of CO poisoning and comorbidities were also found to have significant influences on the risk of developing DNS.HBO may be a risk therapy for treating CO poisoning.