Unintentional Carbon Monoxide Poisoning Outbreak from 2 to 9 October 2019 in Ulaanbaatar, Mongolia

Carbon monoxide poisoning (COP) from 2 to 9 October 2019 was a major public health concern in Ulaanbaatar, Mongolia, after a transition from consumption of raw coal to upgraded briquette fuel. During the period, a total of 186 residents, which is 16 times more than the previous years, were exposed to COP and 6 persons died at home. We conduct a cross-sectional study by using registration data and medical history of all hospitalized patients with a diagnosis of COP from 2 to 9 October 2019 and had an in-depth interview. 144 (77.4%) people from 85 households registered as potential cases and 124 (86.1%) people were diagnosed with COP. All households used upgraded briquettes, and 41 households (48.2%) used them for the first time. In 50% of cases, the stove was broken, the chimney was short, not heated, and the clay joint connecting the wall stove was broken. The majority of interviewees were unaware of COP and improperly used briquettes, and the safety of chimneys and stoves was insufficient which caused unintentional COP. It is necessary to provide information to the local population about the potential risks of COP, install CO alarms in households, and educate the population. In further, a well-established poisoning surveillance system is an important aspect of public health emergency preparedness in Mongolia.

Acute carbon monoxide poisoning and delayed neurological sequelae: a potential neuroprotection bundle therapy

Currently, there is no known optimal therapy for carbon monoxide （CO） poisoning and CO-associated delayed neu- rological sequelae. Hyperbaric oxygen therapy （HBOT） is a well-known treatment method, but its use for CO poison- ing patients is controversial to use due to lack of evidences regarding its efficacy. Thus, it is unlikely that HBOT alone will be accepted as the standard treatment method. In this article, current and potential treatment methods of CO poi- soning are presented as well as the tentative multi-factorial pathophysiology. A series of treatments are suggested for use as a bundle therapy, with targeted temperature management as the base treatment method. Such a therapy holds a great potential, especially for the cases where HBOT is not readily available. We suggest further investigations for elucidating the effects of these suggested treatments and their roles in terms of the complex pathophysiology of CO poisoning. Future ac- ceptance of this therapy based on the improved scientific and clinical knowledge may result in injury prevention and mini- mization of the signs and the symptoms in CO poisoning.

Early Biomarkers in 1H Nuclear Magnetic Resonance Spectroscopy of Striatal Pathological Mechanisms after Acute Carbon Monoxide Poisoning in Rats

Objective In vivo Proton Magnetic Resonance Spectroscopy （1H-MRS） can be used to evaluate the levels of specific neurochemical biomarkers of pathological mechanisms in the brain. Methods We conducted T2-Weighted Magnetic Resonance Imaging （MRI） and 1H-MRS with a 3.0-Tesla animal MRI system to investigate the early microstructural and metabolic profiles in vivo in the striatum of rats following carbon monoxide （CO） poisoning. Results Compared to baseline, we found significant cortical surface deformation, cerebral edema changes, which were indicated by the unclear gray/white matter border, and lateral ventricular volume changes in the brain. A significant reduction in the metabolite to total creatine （Cr） ratios of N-acetylaspartate （NAA） was observed as early as 1 h after the last CO administration, while the lactate （Lac） levels increased marginally. Both the Lac/Cr and NAA/Cr ratios leveled off at 6 h and showed no subsequent significant changes. In addition, compared to the control, the choline （Cho）/Cr ratio was slightly reduced in the early stages and significantly increased after 6 h. In addition, a pathological examination revealed mild cerebral edema on cessation of the insult and more severe cerebral injury after additional CO poisoning. Conclusion The present study demonstrated that 1H-MRS of the brain identified early metabolic changes after CO poisoning. Notably, the relationship between the increased Cho/Cr ratio in the striatum and delayed neuropsychologic sequelae requires further research.

Occupational Carbon Monoxide Poisoning Associated with Diesel Motor Operation in an Air-raid Shelter in June 2015, Jinan City, China-An Epidemiological Investigation

Carbon monoxide （CO） is an odorless, colorless gas produced by incomplete combustion of carbonbased compounds. Exposure to CO can cause various adverse health effects ranging from headache and fatigue to coma and death. Thousands of illnesses and deaths have been documented through CO poisoning surveillance systems and accident investigations each year.

Spatiotemporal Distribution and Epidemiological Characteristics of Hospital Admissions for Carbon Monoxide Poisoning in Guangdong,China,2013-2020

Objective This study aimed to determine the spatiotemporal distribution and epidemiological characteristics of hospital admissions for carbon monoxide poisoning(COP)in Guangdong,China,from 2013 to 2020.Methods Data on age-and sex-specific numbers of hospital admissions due to COP in Guangdong(2013-2020)were collected.Daily temperatures were downloaded through the China Meteorological Data Sharing Service System.We analyzed temporal trends through time series decomposition and used spatial autocorrelation analysis to detect spatial clustering.The distributed lag nonlinear model was used to quantify the effects of temperature.Results There were 48,854 COP admissions over the study period.The sex ratio(male to female)was1:1.74.The concentration ratios(M)ranged from 0.73-0.82.The highest risk occurred in January(season index=3.59).Most cases were concentrated in the northern mountainous areas of Guangdong with high-high clustering.COP in the study region showed significant spatial autocorrelation,and the global Moran’s I value of average annual hospital admission rates for COP was 0.447(P<0.05).Low temperatures were associated with high hospital admission rates for COP,with a lag lasting 7 days.With a lag of 0 days,the effects of low temperatures[5th(12℃)]on COP were 2.24-3.81,as compared with the reference temperature[median(24℃)].Conclusion COP in Guangdong province showed significant temporal and spatial heterogeneity.Low temperature was associated with a high risk of COP,and the influence had a lag lasting 7 days.

An assessment of antioxidant status in patients with carbon monoxide poisoning

BACKGROUND: Carbon monoxide poisoning(COP) is an important cause of mortality and morbidity worldwide. This study was to investigate the levels of serum paraoxonase(PON), arylesterase(ARYL), ceruloplasmin(Cp), and sulfhydryl(-SH) in the treatment of COP, and to further understand the pathophysiology of COP.METHODS: This prospective study comprised 107 individuals with COP(group 1) and 50 healthy volunteers(group 2). Serum, plasma, and erythrocyte samples were taken on admission from all participants with COP. This process was repeated in the 90 th and 180 th minutes of treatment. Samples were taken from the control group only once. The levels of plasma PON, ARYL, Cp activity and-SH were measured in both groups.RESULTS: Age, gender, and carboxyhemoglobin level were not correlated with PON, ARYL, Cp, and-SH levels. PON, ARYL, and-SH levels were signifi cantly decreased in group 1 compared with group 2. Conversely, Cp was signifi cantly elevated in group 1 in contrast to group 2. Although ARYL was lower on admission in patients with COP than that was observed in the 90 th and 180 th minutes(P<0.001), Cp was higher on admission than at the other time points(P<0.001).CONCLUSIONS: Participants with COP had decreased levels of antioxidants(PON, ARLY, and-SH). COP represses the antioxidant system.

Massive subdural hematoma misdiagnosed as delayed encephalopathy of carbon monoxide poisoning: a case report and literature review

Subdural hematoma is often secondary to brain trauma and other diseases.The onset is hidden and the condition is critical.Timely detection and early treatment are particularly important.The patient denied a history of trauma,but had a history of consciousness loss after charcoal burning.The clinical symptoms were progressive cognitive impairment.The initial diagnosis was delayed encephalopathy caused by carbon monoxide poisoning.However,computed tomography(CT)scan of the brain showed a large area of subdural hematoma on the left side and the formation of a cerebral hernia,which was life-threatening.The patienfs symptoms gradually improved after an emergency operation.

Multimodality evoked potentials in patients with delayed encephalopathy after acute carbon monoxide poisoning

Objective： To evaluate the diagnostic and prognostic values in patients with delayed encephalopathy after acute carbon monoxide poisoning. Methods： The tibial nerve somatosensory evoked potentials （SEPs）, vision evoked potentials （VEPs）, and brain stem audition evoked potentials（BAEPs） were performed in 32 healthy adults and 43 patients with delayed encephalopathy after acute carbon monoxide poisoning. Results： This paper indicated abnormalities of tibial nerve SEPs in 31 patients （31/43, 72.1%）, VEPs in 17 patients （17/28, 60.7%）, and BAEPs in 14, patients （14/43, 32.6%）. These results showed that the greatest diagnostic value was SEPs, followed by VEPs and, BAEPs with the lowest sensitivity. Conclusion： Multimodality evoked potentials （EPs） can be used for evaluating the diagnostic and prognostic values in cases of delayed encephalopathy after acute carbon monoxide poisoning.

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.

Effects of nimodipine and fructose-1,6-diphosphate on cerebral damage in carbon monoxide poisoning mice

Objective To study the dose- and time- dependent protective effects and the synergistic effects of nimodipine (NMDP) and fructose-1,6-diphosphate (FDP) against cerebral damage induced by acute carbon monoxide (CO) poisoning in mice. Methods Male mice were exposed to CO 170 mL/kg, i.p. After CO intraperitonealy exposure, mortality of mice, change in memory function estimated by passive avoidance test, the pathomorphologic observation of brain tissue slices, as well as changes of activities of monoamine oxidase (MAO)-B and Ca 2+-Mg 2+-ATPase in cerebral tissue were studied. In dose-dependent protective effect study, NMDP (10.6, 5.3, 2.7 mg/kg) and FDP (2.6, 1.3, 0.67 g/kg) was injected ip, respectively 15 min after CO exposure. To study the time-effect relationship of drugs, NMDP (5.3 mg/kg) and FDP (1.3 g/kg) were administered ip respectively 15 minutes, 45 minutes and 120 minutes after CO exposure. The combination of NMDP (2.7 mg/kg) and FDP (0.67 g/kg) was administered ip15 minutes, 45 min and 120 minutes after CO exposure to study the synergism of the two drugs. Results Either NMDP (10.6, 5.3 mg/kg) or FDP (2.6, 1.3 g/kg) administered ip within 15 minutes after CO exposure significantly decreased the impairment of memory function and mortality rate induced by CO, inhibited the decrease of Ca 2+-Mg 2+-ATPase activity, blunted the rising of MAO-B activity and prevented the delayed hippocampal neuronal death in poisoning mice. To our surprise, the combined use of NMDP (2.7 mg/kg) and FDP (0.67 g/kg) within 15 minutes after CO exposure had similar effects to that in NMDP (10.6, 5.3 mg/kg) and FDP (2.6, 1.3 g/kg). Conclusions These results suggest that the impairment of CO on brain can be attenuated if NMDP or FDP are administered sufficiently and quickly as soon as possible after CO exposure and there exists a synergism of FDP and NMDP against CO poisoning damage.

Prevalence of Acute Myocardial and Brain Toxicity in Emergency Department Patients Exposed to Carbon Monoxide

Introduction: Due to its severe toxicity, carbon monoxide poisoning is an emergency that leads to cardiac and brain involvement, and emergency physicians should aim to master this diagnosis. This study is intended to describe the expected prevalence of these severe toxicities in the emergency department. Materials and Methods: A retrospective cohort of consecutive patients over 16 years of age presenting with carbon monoxide poisoning to the emergency department of the Hospital Universitario Austral, Argentina, during the period from January 2018 to June 2022. The prevalence of myocardial and brain toxicity was assessed regarding percentage, continuous variables with mean and standard deviation, categorical variables with percentage and absolute frequency. Positive findings of acute neurological toxicity included seizures, syncope and coma, while cardiovascular toxicity encompassed acute myocardial infarction (MI) diagnosed by electrocardiogram or elevated troponin levels, arrhythmias, and the development of pulmonary edema/ congestive heart failure (CHF) confirmed by chest X-ray with suggestive signs or clinically compatible symptoms. Patients were followed-up for 90 days to estimate hospitalization and mortality. Results: A total of 67 patients were evaluated;44.77% of them were males with a mean age of 38.5 ± 14.97 years. The prevalence of acute myocardial toxicity was 7.46% (n: 5). Among these patients, 3 had overweight as a risk factor, and 3 showed ECG abnormalities with negative T-waves. The prevalence of acute brain toxicity was 8.9% (n: 6). In total, 37% (n: 25) of patients met the criteria for hyperbaric oxygen therapy, of which 32% (n: 8) underwent more than one session. A total of 7.46% of patients (n: 5) required hospitalization. Mortality at 90 days was 0%. Conclusion: Among the patients who presented to the emergency department, the prevalence of acute myocardial toxicity was 7.46% (n: 5), which is lower than the prevalence reported in other studies to date. The prevalence of acute brain toxicity was 8.9% (n: 6), and there are no studies describing the prevalence of acute brain toxicity in the emergency department to date. There were no fatalities in our series.

Hippocampus hypoxia-inducible factor-1 alpha and heme oxygenase-1 expression in the delayed encephalopathy after acute carbon monoxide poisoning rat model

Objective To research the expression of hypoxia-inducible factor-1 alpha(HIF-1α)and heme oxygenase-1(HO-1)in hippocampus of rats with delayed encephalopathy after acute carbon monoxide poisoning(DEACMP)and its functions.Methods One hundred and fiftysix rats were selected and randomly divided into

Effects of intravascular laser phototherapy on delayed neurological sequelae after carbon monoxide intoxication as evaluated by brain perfusion imaging:A case report and review of the literature

BACKGROUND Delayed neurological sequelae(DNS)caused by carbon monoxide(CO)intoxication poses considerable treatment challenges for clinical practitioners.In this report,we used nuclear medicine imaging and the Mini-Mental State Examination(MMSE)to evaluate the effectiveness of intravascular laser irradiation of blood(ILIB)therapy for the management of DNS.CASE SUMMARY A 51-year-old woman presented to our medical center experiencing progressive bradykinesia,rigidity of limbs,gait disturbance,and cognitive impairment.Based on her neurological deficits,laboratory tests and imaging findings,the patient was diagnosed with delayed neurological sequelae of CO intoxication.She received intensive rehabilitation and ILIB therapy during 30 sessions over 2 mo after diagnosis.Brain single-photon emission computed tomography was performed both prior to and after ILIB therapy.The original hypoperfusion area in bilateral striata,bilateral frontal lobe,right parietal lobe,and bilateral cerebellum showed considerable improvement after completion of therapy.The patient’s MMSE score also increased markedly from 6/30 to 25/30.Symptoms of DNS became barely detectable,and the woman was able to carry out her daily living activities independently.CONCLUSION ILIB therapy could facilitate recovery from delayed neurological sequelae in patients with CO intoxication,as demonstrated by improved cerebral blood flow and functional outcomes in our patient.

The application of extended modified Lambert Beer model for measurement of blood carboxyhemoglobin and oxyhemoglobin saturation

This work presents the use of extended Modified Lambert Beer(MLB)model for accurate andcontinuous monitoring of percent blood carboxyhemoglobin(COHb)(SCO)and oxyhemoglobin(OxyHb)saturation(SO,)via a fitting procedure.This quantification technique is based on theabsorption characteristics of hemoglobin derivatives in the wavelength range of 520-600 nm togive the best estimates of the required parameters.A comparison of the performance of the developed model and MILB law is made using attenuation data from Monte Carlo simulations for a two-layered skin model.The results revealed a lower mean absolute error of 0.4%in the valuesestimated by the developed model as compared to 10%that is given by the MILB law.This studyshowed that the discussed approach is able to provide consistent and accurate measurement ofblood SO,and SCO across diferent skin pigmen tations suggesting that it may potentially be usedas an alternative means for clinical diagnosis of carbon monoxide(CO)poisoning.