The Prognostic Effect of Air Pollution in Patients Presenting to the Emergency Department with Carbon Monoxide Poisoning.

OBJECTIVE: Weather conditions such as low air temperatures, low barometric pressure, and low wind speed have been linked to more cases of carbon monoxide (CO) poisoning. However, limited literature exists regarding the impact of air pollution. This study aims to investigate the relationship between outdoor air pollution and CO poisoning in 2 distinct cities in Turkey. METHODS: A prospective study was conducted at 2 tertiary hospitals, recording demographic data, presenting complaints, vital signs, blood gas and laboratory parameters, carboxyhemoglobin (COHb) levels, meteorological parameters, and pollutant parameters. Complications and outcomes were also documented. RESULTS: The study included 83 patients (Group 1 = 44, Group 2 = 39). The air quality index (AQI) in Group 2 (61.7 ± 27.7) (moderate AQI) was statistically significantly higher (dirtier AQI) than that in Group 1 (47.3 ± 26.4) (good AQI) (P = 0.018). The AQI was identified as an independent predictor for forecasting the need for hospitalization (OR = 1.192, 95% CI: 1.036 - 1.372, P = 0.014) and predicting the risk of developing cardiac complications (OR: 1.060, 95% CI: 1.017 - 1.104, P = 0.005). CONCLUSIONS: The AQI, derived from the calculation of 6 primary air pollutants, can effectively predict the likelihood of hospitalization and cardiac involvement in patients presenting to the emergency department with CO poisoning.

Stroke on ECG: a cerebral T-wave change secondary to acute carbon monoxide poisoning.

In clinical management of carbon monoxide (CO) poisoning, serum cardiac enzyme biomarkers and electrocardiogram (ECG) are both highly recommended emergency check-ups to evaluate myocardial injuries. Medical imaging - including head CT or MRI - are not routine for CO poisoning emergency management. We herein report on a comatose patient who was diagnosed with cerebral infarction secondary to 24 hours previous acute CO poisoning, warned by a typical cerebral-type T waves on ECG in advance, and confirmed by a head MRI. Fortunately, the patient made a full recovery based on a timely treatment with medications and hyperbaric oxygen (HBO2) therapy. We would like to propose that a vital, stable, conscious CO poisoning patient who remains a higher risk for hemorrhagic or ischemic stroke should be closely monitored for potential neurological abnormalities, and a continuous ECG monitoring should be reinforced throughout the treatment. A head MRI or CT is a priority in evaluating the secondary cerebral stroke and should be arranged immediately in the event of an abnormal ECG or if unusual new symptoms are apparent.

Mass Carbon Monoxide Poisoning on a Train in Italy, March 1944. History Reconstructed.

World War II was approaching its end in Italy in 1944 when one of the worst train disasters in world history occurred near the small town of Balvano in the Apennine Mountains. The train did not derail or crash into something as in most major train disasters. Instead, it entered a mountainous railway tunnel, and when it emerged, over 500 passengers were dead from carbon monoxide poisoning. The event was not allowed to be publicized for almost two decades. This manuscript reconstructs the story of possibly the most significant incident of carbon monoxide mortality ever recorded.

Carbon Monoxide Poisoning (Reprinted from the 2023 Hyperbaric Indications Manual 15th edition).

Despite established exposure limits and safety standards, and the availability of carbon monoxide (CO) alarms, each year an estimated 50,000 people in the United States visit emergency departments for CO poisoning. Carbon monoxide poisoning can occur from brief exposures to high levels of CO or from longer exposures to lower levels. If the CO exposure is sufficiently high, unconsciousness and death occur quickly, and without symptoms. With non-lethal exposures to CO, common symptoms include headaches, nausea and vomiting, dizziness, general malaise, and altered mental status. Some patients may have chest pain, shortness of breath, and myocardial ischemia, and may require mechanical ventilation and treatment of shock. Individuals poisoned by CO often develop brain injury. As with brain injury from non- CO causes such as traumatic brain injury, the clinical expression of brain injury caused by CO poisoning includes the domains of cognition, affect, neurological, and somatic. Common problems are neurological: imbalance, motor weakness, neuropathies, hearing loss, tinnitus, Parkinson's-like syndrome, vestibular, gaze, auditory processing, cognitive, anxiety and depression, posttraumatic stress, personality change, persistent headaches, dizziness, sleep problems, and others. In addition, some will have cardiac or other problems. While breathing oxygen hastens the removal of carboxyhemoglobin (COHb), hyperbaric oxygen (HBO2) hastens COHb elimination and favorably modulates inflammatory processes instigated by CO poisoning, an effect not observed with breathing normobaric oxygen. Hyperbaric oxygen improves mitochondrial function, inhibits lipid peroxidation transiently, impairs leukocyte adhesion to injured microvasculature, and reduces brain inflammation caused by CO-induced adduct formation of myelin basic protein. Based upon supportive randomized clinical trials in humans and considerable evidence from animal studies, HBO2 should be considered for all cases of acute symptomatic CO poisoning. Hyperbaric oxygen is indicated for CO poisoning complicated by cyanide poisoning, often concomitantly with smoke inhalation.

Early and late adverse clinical outcomes of severe carbon monoxide intoxication: A cross-sectional retrospective study.

BACKGROUND: Carbon monoxide (CO) results from incomplete combustion of carbon-based materials, causing symptoms such as headaches, dizziness, nausea, chest pain, confusion, and, in severe cases, unconsciousness. Normobaric oxygen therapy (NBOT) is the standard therapy, whereas hyperbaric oxygen therapy (HBOT) is recommended in severe cases of organ damage. This study examined the early and late adverse outcomes in patients with severe CO poisoning. MATERIALS AND METHODS: This study analyzed severe cases of CO poisoning among patients admitted to the emergency department between January 2020 and May 2022. The demographic, clinical, and laboratory data of symptomatic individuals and those requiring HBOT were examined. The study recorded early outcomes, such as intubation and in-hospital mortality, and late outcomes, such as delayed neurological sequelae and 1-year mortality. Chi-square tests, Spearman's rho correlation tests, and logistic regression analyses were performed to identify factors affecting these outcomes. RESULTS: Patients who received HBOT showed a significant difference in delayed neurological sequelae (DNS) compared to those who received NBOT (p = 0.037). Significant differences were observed in the need for intubation, in-hospital mortality, and 1-year mortality between patients based on COHb levels, but no significant differences were found in DNS. The 1-year mortality probability was significantly influenced by COHb level (odds ratio = 1.159, 95% CI [1.056-1.273]). Patients receiving NBOT had a higher odds ratio for DNS risk than those receiving HBOT (odds ratio = 8.464, 95% [1.755-40.817], p = 0.008). CONCLUSION: The study showed no differences in intubation, in-hospital mortality, and 1-year mortality rates between the HBOT and NBOT groups. However, significant differences in DNS suggest that treatment modalities have different effects on neurological outcomes. High COHb levels are associated with an increased risk of intubation, and mortality underscores the significance of monitoring COHb levels in clinical evaluations.

Hypothyroidism following carbon monoxide poisoning: An epidemiological study supported by animal experiments.

Previous studies have suggested a possible association between carbon monoxide poisoning (COP) and hypothyroidism, but the evidence is limited. Therefore, the aim of this study was to further investigate this relationship. Using data from the Taiwan National Health Research Database, we identified 32,162 COP patients and matched with 96,486 non-COP patients by age and index date for an epidemiological study. The risk of hypothyroidism was compared between the two cohorts until 2018. Independent predictors of hypothyroidism were analyzed using competing risk analysis. An animal study was also conducted to support the findings. COP patients had an increased risk of hypothyroidism compared to non-COP patients in the overall analysis (adjusted hazard ratio [AHR]= 3.88; 95 % confidence interval [CI]: 3.27-4.60) and in stratified analyses by age, sex, and comorbidities. The increase in the overall risk persisted even after more than six years of follow-up (AHR= 4.19; 95 % CI: 3.18-5.53). Independent predictors of hypothyroidism, in addition to COP, included age ≥65 years, female sex, hyperlipidemia, and mental disorder. The animal study showed damages in the hypothalamus, pituitary gland, and thyroid, as well as altered hormone levels 28 days after COP exposure. The epidemiological results showed an increased risk of hypothyroidism in COP patients, which was further supported by the animal study. These findings suggest the need for close monitoring of thyroid function in COP patients, especially in those who are age ≥65 years, female, and have hyperlipidemia or mental disorder.

Development of a risk prediction nomogram for delayed neuropsychiatric sequelae in patients with acute carbon monoxide poisoning.

OBJECTIVES: Delayed neuropsychiatric sequelae (DNS) are critical complications following acute carbon monoxide (CO) poisoning that can substantially affect the patient's life. Identifying high-risk patients for developing DNS may improve the quality of follow-up care. To date, the predictive DNS determinants are still controversial. Consequently, this study aimed to construct a practical nomogram for predicting DNS in acute CO-poisoned patients. METHODS: This retrospective study was conducted on patients with acute CO poisoning admitted to the Tanta University Poison Control Center (TUPCC) from December 2018 to December 2022. Demographic, toxicological, and initial clinical characteristics data, as well as laboratory investigation results, were recorded for the included patients. After acute recovery, patients were followed up for six months and categorized into patients with and without DNS. RESULTS: Out of 174 enrolled patients, 38 (21.8%) developed DNS. The initial Glasgow Coma Scale (GCS), carboxyhemoglobin (COHb) level, CO exposure duration, oxygen saturation, PaCO2, and pulse rate were significantly associated with DNS development by univariate analysis. However, the constructed nomogram based on the multivariable regression analysis included three parameters: duration of CO exposure, COHb level, and GCS with adjusted odd ratios of 1.453 (95% CI: 1.116-1.892), 1.262 (95% CI: 1.126-1.415), and 0.619 (95% CI: 0.486-0.787), respectively. The internal validation of the nomogram exhibited excellent discrimination (area under the curve [AUC] = 0.962), good calibration, and satisfactory decision curve analysis for predicting the DNS probability. CONCLUSIONS: The proposed nomogram could be considered a simple, precise, and applicable tool to predict DNS development in acute CO-poisoned patients.

Hyperbaric Medicine in Pediatrics - reality of a Portuguese reference center.

OBJECTIVE: To identify and characterize the population of Pediatric patients referred to our hyperbaric oxygen therapy center. METHODS: Retrospective and observational study, including pediatric patients treated with hyperbaric oxygen therapy, from 2006 to 2021, at the hyperbaric medicine reference center in the north of Portugal. Variables of interest were extracted from electronic medical records. RESULTS: Our study included 134 patients. The most frequent reasons for referral were carbon monoxide poisoning (n=59) and sudden sensorineural hearing loss (n=41). In 75 cases (56%), treatment was initiated in an urgent context. Symptom presentation at Emergency Department varied among patients, the most frequent being headache and nausea/vomiting. Concerning carbon monoxide poisoning, the most common sources were water heater, fireplace/brazier, and boiler. Regarding adverse effects, it was identified one case of intoxication by oxygen and four cases of middle ear barotrauma. CONCLUSIONS: The most frequent cause for referral was carbon monoxide poisoning. All patients evolved favorably, with few side effects being reported, emphasizing the safety of this therapy. While most pediatricians may not be aware of the potential benefits arising with hyperbaric oxygen therapy, it is of upmost importance to promote them, so that this technique is increasingly implemented.

Risk of lung diseases in patients with previous carbon monoxide poisoning: a nationwide population-based cohort study in the Republic of Korea.

INTRODUCTION: Carbon monoxide poisoning is associated with severe damage to various organs. In this study, we aimed to determine if previous carbon monoxide poisoning was associated with an increased risk of lung diseases. METHODS: The study population was derived from the National Health Insurance Service database of Korea between 1 January 2002 and 31 December 2021. Adults with carbon monoxide poisoning, with at least one visit to medical facilities between 2002 and 2021, were included. For comparison, an equal number of matched controls with the same index date were selected from the database. RESULTS: A total of 28,618 patients with carbon monoxide poisoning and 28,618 matched controls were included in this study. Approximately 42.8 per cent of the patient and control groups were female, with a mean age of 51.3 years. In patients with carbon monoxide poisoning, there was a significant increase in the risk of lung cancer (adjusted hazard ratio, 1.84; 95 per cent confidence interval, 1.42-2.39; P < 0.001), chronic obstructive pulmonary disease (adjusted hazard ratio, 1.60; 95 per cent confidence interval, 1.36-1.89; P < 0.001), pulmonary tuberculosis (adjusted hazard ratio, 1.46; 95 per cent confidence interval, 1.13-1.88; P = 0.003), and non-tuberculous mycobacterial infection (adjusted hazard ratio, 1.54; 95 per cent confidence interval, 1.01-2.36; P = 0.047). DISCUSSION: In this retrospective cohort study, previous carbon monoxide poisoning was associated with an increased risk of lung cancer, chronic obstructive pulmonary disease, pulmonary tuberculosis, and non-tuberculous mycobacterial infection. Further studies are needed to confirm such an association in other populations and the risk of lung diseases due to the toxic effect of carbon monoxide from different sources. CONCLUSIONS: Previous carbon monoxide poisoning was associated with an increased risk of lung diseases, but the relative importance of the causes and sources of exposure was not known. The long-term management of survivors of acute carbon monoxide poisoning should include monitoring for lung cancer, chronic obstructive pulmonary disease, pulmonary tuberculosis, and non-tuberculous mycobacterial infection.

Quantification of referrals received at two emergency-capable hyperbaric medicine centers.

Emergency hyperbaric oxygen treatment capability is limited in the United States, and there is little documentation of calls received by centers available 24 hours a day, seven days a week, 365 days a year. Our study aimed to calculate the number of calls received for urgent hyperbaric oxygen (HBO2). We logged calls from two HBO2 chambers on the East Coast of the United States that serve a densely populated region in 2021. The total number of emergency calls was 187 at the University of Maryland (UMD) and 127 at the University of Pennsylvania (UPenn). There were calls on 180/365 (46%) days during the study period at UMD and 239/365 (63%) days at UPenn. The most common indication was carbon monoxide toxicity. The peak month of calls was March. Emergency HBO2 calls are common, and more centers must accept emergency cases. Data from geographically diverse centers would add generalizability to these results and capture more diving-related emergencies.

[A case of massive intrathecal hematoma of the rectus abdominis secondary to acute severe carbon monoxide poisoning].

Acute carbon monoxide poisoning can cause hypoxic injury to multiple organs. Neurological impairment and cardiac dysfunction are common manifestations of severe poisoning patients, but hemorrhagic complications are rare in clinic. The clinical diagnosis and treatment of a case of massive intrathecal hematoma of the rectus abdominis secondary to acute severe carbon monoxide poisoning was reported. The pathophysiological mechanism and treatment strategy of rectus sheath hematoma secondary to acute severe carbon monoxide poisoning was analyzed, in order to improve the understanding of hemorrhagic complications of carbon monoxide poisoning. This case suggests that for patients with a history of cardiovascular disease and taking anticoagulants, clinicians should be alert for the risk of bleeding when making medical decisions.

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.

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.

Analysis of factors associated with the development of delayed encephalopathy following acute carbon monoxide poisoning.

In this study, we analyzed the factors influencing the development of delayed encephalopathy in patients with acute carbon monoxide poisoning (ACOP) (DEACMP) following conventional treatment such as hyperbaric oxygen therapy (HBOT). Between January 2012 and January 2022, we retrospectively analyzed 775 patients with ACOP, who were admitted to the Second Department of Rehabilitation Medicine and received HBOT in the Second Hospital of Hebei Medical University. These patients were divided into the non-DEACMP and DEACMP groups based on their follow-up; we then compared the general data, clinical characteristics, admission examination, and treatment between the two groups to identify risk factors for the development of DEACMP. The DEACMP group comprised of 168 cases, while the non-DEACMP group consisted of 607 cases. Univariate analysis showed that there were 20 possible prognostic factors in the non-DEACMP and DEACMP groups. The results of multivariable regression analyses suggested that the occurrence of DEACMP was significantly correlated with advanced age, the combination of multiple medical histories, the duration of CO exposure, the duration of coma, poisoning degree, the Interval between ACOP and the first HBOT, the total number of HBOTs, and the combination with rehabilitation treatment. DEACMP patients who are older, have more comorbidities, prolonged CO exposure, prolonged coma, severe intoxication, long intervals between ACOP and the first HBOT, fewer HBOT treatments, and who are not treated with a combination of rehabilitative therapies have a poor prognosis.

Forensic utility of carboxyhemoglobin levels in postmortem spleen specimens in South Korea.

In order to determine whether CO poisoning was the definitive cause of death, the concentration of carboxyhemoglobin (COHb) in spleen specimens was analyzed using a gas chromatography-thermal conductivity detector. 125 cases of forensic autopsy reports containing COHb analysis requests were analyzed and subdivided into two groups, improbable and highly probable of CO intoxication. In the first group which consists of 100 cases, the results of COHb analysis were negative, and the circumstances of death, as well as the postmortem findings could not validate the exposure to CO. In the second group which consists of 25 cases, the results of COHb were positive, and both postmortem findings and circumstances of death confirmed the exposure to CO. In the cases of indoors and vehicle fires or those including the use of briquettes, COHb levels reached 43.1-97.5 %, whereas in individuals without any feature of CO poisoning had COHb level high as 29.8 %. However, certain cases without any connection to fire nor CO exposure also contained significant amount of CO based on post-mortem analysis. This study focuses on cases without any relationship to fire or CO and proves that COHb levels below 30 % may be considered as a contributing factor to but not exclusively as the cause of death.

Curcumin as a Potential Therapeutic Agent for Mitigating Carbon Monoxide Poisoning: Evidence from an Experimental Rat Study.

BACKGROUND Carbon monoxide (CO) is a poisonous gas and causes tissue damage through oxidative stress. We aimed to investigate the protective value of curcumin in CO poisoning. MATERIAL AND METHODS Twenty-four female Spraque Dawley rats were divided into 4 subgroups: controls (n=6), curcumin group (n=6), CO group (n=6), and curcumin+CO group (n=6). The experimental group was exposed to 3 L/min of CO gas at 3000 ppm. Curcumin was administered intraperitoneally at a dosage of 50 mg/kg. Hippocampal tissues were removed and separated for biochemical and immunohistochemical analysis. Tissue malondialdehyde (MDA) levels, nitric oxide (NO) levels, and superoxide dismutase (SOD) and catalase (CAT) activities were assayed spectrophotometrically, and serum asymmetric dimethylarginine (ADMA) were measured using the ELISA technique. Tissue Bcl-2 levels were detected by the immunohistochemistry method. RESULTS Tissue CAT and SOD activities and NO levels were significantly lower, and MDA and serum ADMA levels were higher in the CO group than in the control group (P<0.001). The curcumin+CO group had higher CAT activities (P=0.007) and lower MDA than the CO group (P<0.001) and higher ADMA levels than the control group (P=0.023). However, there was no significant difference observed for tissue SOD activity or NO levels between these 2 groups. In the curcumin+CO group, the Bcl-2 level was higher than that in the CO group (P=0.017). CONCLUSIONS The positive effect of curcumin on CAT activities, together with suppression of MDA levels, has shown that curcumin may have a protective effect against CO poisoning.

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.

Biochemical parameters and clinical outcomes of carbon monoxide poisoning in special groups: children, pregnant women, and the elderly.

OBJECTIVE: Carbon monoxide (CO), a toxic gas, poses a significant threat to human health. Children, pregnant women, and elderly individuals are particularly vulnerable to this toxicity. This study aims to evaluate the demographic and clinical characteristics of pediatric, pregnant, and geriatric patients. PATIENTS AND METHODS: The study included pediatric, pregnant, and geriatric patients with a confirmed diagnosis of CO poisoning, excluding those with complete file data and those with carboxyhemoglobin (COHb) levels below 5% (for children and pregnant patients) and 10% (for elderly patients). Patients aged < 18 years, > 65 years, and pregnant patients admitted to the adult and pediatric emergency departments were included in the study; statistical analyses were conducted using SPSS Inc., with a p-value of < 0.05 considered statistically significant. RESULTS: For pediatric patients, a statistically significant difference was observed between the two groups in terms of their main complaints, which were primarily attributed to neurological and general symptoms. A positive correlation was found between follow-up time and several factors, including white blood cell (WBC) count and troponin, lactate, lactate dehydrogenase (LDH), and COHb levels. For pregnant patients, no in-hospital mortality was observed in the patients included in this study. A significant negative correlation was identified between age and both COHb and hemoglobin (Hb) levels. A strong positive correlation was found between the COHb levels and hospital follow-up time. For elderly patients, no significant differences were found between the two treatment modalities. Notably, higher COHb levels on admission were associated with a more fatal in-hospital course, with COHb levels > 40% of all patients requiring intubation. CONCLUSIONS: Vulnerable populations are at increased risk of exposure to CO, and the study results emphasize the necessity of heightened awareness and preventive measures to safeguard these individuals from CO poisoning.