Serum lactate as a predictor of neurologic outcome in ED patients with acute carbon monoxide poisoning

Clinical and Echocardiographic Predictors for the Presence of Late Gadolinium Enhancement on Cardiac Magnetic Resonance Imaging in Patients with Carbon Monoxide Poisoning

Late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMRI) reflects the burden of myocardial damage in carbon monoxide (CO) poisoning. This study aimed to identify the clinical and echocardiographic parameters that can predict myocardial LGE on CMRI in CO poisoning. This prospective observational study included patients who presented with acute CO poisoning and elevated troponin I and underwent echocardiography and CMRI to identify myocardial damage at a tertiary university hospital between August 2017 and May 2019 and August 2020 and July 2022. Based on the CMRI findings, participants were categorized into LGE and non-LGE groups. The median age of the 155 patients was 51.0 years, and 98 (63.2%) were males. Median times from emergency department arrival to either CMRI or echocardiography were 3.0 days each. The LGE group included 99 (63.9%) patients with LGE positivity on CMRIs. Time from rescue to hyperbaric oxygen therapy >4 h (odds ratio (OR): 3.31, 95% confidence interval (CI): 1.28-8.56, p = 0.01); serum lactate levels >2 mmol/L (OR: 2.62, 95% CI: 1.20-5.73, p = 0.02); and left ventricular global longitudinal strain >-16% (OR: 2.95, 95% CI: 1.35-6.47, p = 0.007) were significant predictors of LGE positivity. The area under the curve of these predictors was 0.711. Our prediction model, which combines the clinical parameters with left ventricular global longitudinal strain, may be helpful in the early detection of LGE positivity.

The effect of full blood count and cardiac biomarkers on prognosis in carbon monoxide poisoning in children

AIMS

In this study, cardiac biomarkers, blood parameters, electrocardiography (ECG), and echocardiography were investigated in children with carbon monoxide (CO) poisoning, and the diagnostic value of these parameters was investigated.

METHODS

The demographical, clinical, and laboratory data of children aged 0-18 years who were admitted to the pediatric emergency department due to CO poisoning between January 2019 and January 2022 were retrospectively scanned from medical records. The patients were divided into two groups as troponin-I positive and troponin-I negative.

RESULTS

There were 107 children aged 0-18 years (average age, 10.46 ± 5.77 years; 51% female) with CO poisoning. There were 13 patients with troponin-I positive myocardial injury. Troponin-I was positive in 3 patients whose carboxyhemoglobin (COHb) level was below 2% at the time of admission. In one patient, troponin-I, which was normal at admission, increased by the 24th hour of hospitalization. Hyperbaric oxygen therapy was given due to headache in one patient, although the COHb level of that patient was below 25%. An NT-proBNP level of ≥ 219.5 ng/L predicted the development of troponin-I positivity with a sensitivity of 70% and a specificity of 86.7% (AUC, 0.967 (0.58-0.994); p = 0.017). White blood cell (WBC), neutrophil, neutrophil-to-lymphocyte ratio (NLR), immature granulocyte (IG), and IG% levels were found to be significantly higher in the troponin-positive patient group. DISCUSSION AND CONCLUSION: NT-proBNP has been shown to be an early diagnostic marker for myocardial dysfunction. Additionally, when cardiac markers are not available, full blood parameters may assist clinicians for patient treatment and referral.

Derivation and Validation of a Score for Predicting Poor Neurocognitive Outcomes in Acute Carbon Monoxide Poisoning

IMPORTANCE

Preventing neurocognitive sequelae is a major goal of treating acute carbon monoxide (co) poisoning. There is a lack of reliable score systems exist for assessing the probability of these sequelae.

OBJECTIVE

To develop and validate a novel clinical scoring system for predicting poor neurocognitive outcomes after acute co poisoning.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study included derivation and validation cohorts based on consecutive patient data prospectively collected at university hospitals from January 2006 to July 2021 in Wonju, Republic of Korea, and from August 2016 to June 2020 in Incheon, Republic of Korea. Participants included individuals aged 16 years or older admitted with co poisoning. Data were analyzed from October 2021 to January 2022.

EXPOSURES

Clinical and laboratory variables.

MAIN OUTCOMES AND MEASURES

The outcome of interest was neurocognitive sequelae at 4 weeks after co poisoning. Logistic regression models were used to identify predictors of poor neurocognitive outcomes in the derivation cohort. Outcomes were assessed using the Global Deterioration Scale [GDS] at 1-month after co exposure and classified as good (1-3 points) or poor (4-7 points).

RESULTS

A total of 1282 patients (median [IQR] age, 47.0 [35.0-59.0] years; 810 [63.2%] men) were assessed, including 1016 patients in the derivation cohort and 266 patients in the validation cohort. The derivation cohort included 126 patients (12.4%) with poor GDS scores. Among 879 patients in the derivation cohort with 1-year follow-up data, 757 (86.1%) had unchanged GDS scores, 102 (11.6%) had improved GDS scores, and 20 (2.3%) had worsened GDS scores. In the final prediction model, age older than 50 years (1 point), Glasgow Coma Scale score of 12 or less (1 point), shock (1 point), serum creatine kinase level greater than 320 U/L at emergency department presentation (1 point), and no use of hyperbaric oxygen therapy (1 point) remained factors significantly associated with worse outcome; therefore, this scoring system was called COGAS (creatine kinase, hyperbaric oxygen therapy, Glasgow Coma Scale, age, shock). Area under the receiver operating characteristic curve for COGAS score was 0.862 (95% CI, 0.828-0.895) for the derivation cohort and 0.870 (95% CI, 0.779-0.961) for the validation cohort.

CONCLUSIONS AND RELEVANCE

These findings suggest that assessing the COGAS score during the early phase of co poisoning may help identify patients at risk of poor neurocognitive sequelae.

Usefulness of a modified poisoning severity score for predicting prognosis in acute carbon monoxide poisoning

INTRODUCTION

The poisoning severity score (PSS) was developed to grade the severity of various types of poisoning. However, in its current form, it requires investigating many variables, some of which have been found not to be associated with carbon monoxide (CO) poisoning severity. Therefore, in this study, we modified the PSS for CO poisoning and compared its usefulness to that of the original PSS, as an early prognostic factor of short-term outcome in CO poisoning patients.

METHODS

This was a retrospective observational study conducted in patients with CO poisoning who visited the emergency department between January 2014 and December 2020. Patients' primary outcome was their Cerebral Performance Category (CPC) scale score at discharge, which classified those with CPC 1-2 as having a favorable outcome and those with CPC 3-5 as having a poor outcome. We calculated the patients' PSS and their CO-modified PSS by replacing blood and metabolic balance category in the original PSS with carboxyhemoglobin (COHb) and lactate levels, respectively.

RESULTS

This study included 891 patients, of which 852 (95.6%) and 39 (4.4%) were classified into the favorable and poor outcome groups, respectively. Using multivariate analysis, the PSS (odds ratio [OR], 22.961; 95% confidence interval [CI], 10.641-49.546; p < 0.001) and CO-modified PSS (OR, 28.856; 95% CI, 12.874-64.679; p < 0.001) were both found to be associated with poor outcomes at hospital discharge. The areas under the receiver operating characteristic curves for the PSS and CO-modified PSS were 0.874 (95% CI, 0.850-0.895) and 0.881 (95% CI, 0.858-0.901), respectively.

CONCLUSION

The CO-modified PSS, with fewer variables than the original PSS, was not inferior to predict poor outcomes, and if COHb level is considered together with other parameters, then it can be used both for predicting prognosis and in diagnosis.

An analysis of 1344 consecutive acute intoxication cases admitted to an academic emergency medicine department in Turkey

OBJECTIVE:

One of the major causes of emergency department (ED) visits is acute poisoning. Acute intoxications occur soon after either single or multiple exposures to toxic substances, and they started to be a more serious problem in developing countries. The objective of this study was to investigate the local patterns of acute intoxications, as well as clinical and sociodemographic characteristics of patients with acute poisoning, admitted to our hospital’s ED.

METHODS:

This single-center, retrospective study was conducted using medical records of consecutive patients admitted to the ED between January 2016 and December 2017.

RESULTS:

A total of 1344 patients were included in the statistical analysis. Of these, 673 (50.1%) were female. Mean (±SD) age was 32.2 (±12.0), ranging between 17 and 84 years. The highest number of poisoning cases was observed in summer, especially in July (10.0%) and August (11.8%), whereas lowest number of admissions related to poisoning occurred during winter in November (5.1%) and December (5.2%). Among admitted cases, many were suicide attempts (55.7%) followed by non-intentional (accidental) ingestion of non-pharmaceutical (n=553, 41.2%) and pharmaceutical agents (n=42, 3.1%). Single agents were the most common cause of acute intoxications (63.2%) rather than multidrug intoxications. Most frequently observed causes of poisonings were recreational substances (30.0%) and agents exposed by inhalation (13.2%). INR, lactate, and pH levels at admission were significant predictors of 7-day mortality without a significant paired difference between each other. The AUCs for each were 0.89 (SE 0.04; p<0.0001), 0.84 (SE 0.10; p=0.0007), and 0.79 (SE 0.11; p=0.0102), respectively.

CONCLUSION:

We conclude that recreational substances and medicinal drug intoxications were the leading cause of acute poisonings in our region, occurring mostly during the summer.

Use of hyperbaric oxygen therapy for preventing delayed neurological sequelae in patients with carbon monoxide poisoning: A multicenter, prospective, observational study in Japan

BACKGROUND

The purpose of this study was to clarify the practical clinical treatment for acute carbon monoxide (CO) poisoning in Japan and to investigate the efficacy of hyperbaric oxygen (HBO2) therapy in preventing delayed neurological sequelae (DNS) in the acute phase of CO poisoning.

METHODS

We conducted a multicenter, prospective, observational study of acute CO poisoning in Japan. Patients with acute CO poisoning were enrolled and their treatment details were recorded. The primary endpoint was the onset of DNS within 2 months of CO exposure. Factors associated with DNS were assessed with logistic regression analysis.

RESULTS

A total of 311 patients from 57 institutions were registered and 255 were analyzed: 171 received HBO2 therapy (HBO2 group) and 84 did not (normobaric oxygen [NBO2] group). HBO2 therapy was performed zero, once, twice, or three times within the first 24 h in 1.8%, 55.9%, 30.9%, and 11.3% of the HBO2 group, respectively. The treatment pressure in the first HBO2 session was 2.8 ATA (47.9% of the HBO2 group), 2.0 ATA (41.8%), 2.5 ATA (7.9%), or another pressure (2.4%). The incidence of DNS was 13/171 (7.6%) in the HBO2 group and 3/84 (3.6%) in the NBO2 group (P = 0.212). The number of HBO2 sessions in the first 24 h was one of the factors associated with the incidence of DNS (odds ratio, 2.082; 95% confidence interval, 1.101-3.937; P = 0.024).

CONCLUSIONS

The practical clinical treatment for acute CO poisoning, including HBO2 therapy, varied among the institutions participating in Japan. HBO2 therapy with inconsistent protocols showed no advantage over NBO2 therapy in preventing DNS. Multiple HBO2 sessions was associated with the incidence of DNS.

Neurocognitive sequelae after carbon monoxide poisoning and hyperbaric oxygen therapy

Carbon monoxide (CO) has been the leading cause of poisoning mortality in many countries and hyperbaric oxygen (HBO) is a widely accepted treatment for CO poisoning. However, some patients with CO poisoning will still develop neurocognitive sequelae regardless of HBO therapy, which can persist since CO poisoning or be present days to weeks after a recovery from CO poisoning. HBO has been used in the prevention and treatment of neurocognitive sequelae after CO poisoning, and some mechanisms are also proposed for the potential neuroprotective effects of HBO on the neurocognitive impairment after CO poisoning, but there is still controversy on the effectiveness of HBO on neurocognitive sequelae after CO poisoning. In this paper, we briefly introduce the neurocognitive sequelae after CO poisoning, summarize the potential predictive factors of neurocognitive sequelae, and discuss the use of HBO in the treatment and prevention of neurocognitive sequelae after CO poisoning.

Factors Predicting Acute Brain Injury in Cases of Carbon Monoxide Poisoning: A Prospective Registry-Based Study

Carbon monoxide (CO) is one of the most common poisoning substances worldwide. Since acute brain injury (ABI) is an important determinant of the neurological outcome in CO poisoning, screening for patients at a high risk of developing ABI is essential for the proper treatment. This study identified predictors of ABI in patients with CO poisoning. This prospective registry-based study was conducted in patients who visited a tertiary care hospital for CO poisoning from August 2016 to June 2020. ABI was defined as the presence of acute hypoxic lesions on diffusion-weighted magnetic resonance imaging. Multiple logistic regression analysis was performed to identify the predictors of ABI. Of 231 patients, 64 (27.7%) showed ABI. Multiple logistic regression analysis showed that a Glasgow Coma Scale (GCS) score <9 at presentation (odds ratio [OR] 3.28, 95% confidence interval (CI) 1.08–10.01), creatinine level >1.2 mg/dL (OR 3.04, 95% CI 1.16–8.01), and C-reactive protein (CRP) level >9.2 mg/L (OR 4.38, 95% CI 1.41–13.65) predicted ABI in cases of acute CO poisoning. In CO poisoning, the GCS score at presentation, and serum creatinine and CRP levels, were useful predictors of ABI, and may help clinicians identify high-risk patients for whom treatment should be prioritized.

Effects of smoking on delayed neuropsychiatric sequelae in acute carbon monoxide poisoning: A prospective observational study

Smoking is a well-known risk factor for cardio-cerebrovascular disease. However, several studies have reported the "smoker's paradox" whereby smokers have a better prognosis for cardio-cerebrovascular diseases. Similar to cardio-cerebrovascular diseases, hypoxia is one of the major mechanisms of injury in carbon monoxide (CO) poisoning. This study investigated the association between smoking and delayed neuropsychiatric sequelae (DNS) in acute CO poisoning.This study involved patients with CO poisoning treated at a university hospital in Bucheon, Korea between September 2017 and March 2020. The exclusion criteria were age <18 years, discharge against medical advice, loss to follow-up, persistent neurological symptoms at discharge, transfer from another hospital 24 hours after exposure, and transfer from another hospital after hyperbaric oxygen therapy. Logistic regression analysis was performed to find factors associated with DNS.Two hundred sixty three patients visited the hospital due to CO poisoning and of these, 54 were excluded. DNS was evaluated up to 3 months after discharge, and until this time, DNS occurred in 35 (16.8%) patients. And the incidence rate of DNS was lower in smokers than non-smokers (15, 12% vs 20, 23.8%, P = .040). Multivariable logistic regression analysis revealed that CO exposure time (odds ratio [OR] 1.003; confidence interval [CI] 1.001-1.005; P = .003), the Glasgow coma scale (GCS) (OR 0.862; CI 0.778-0.956; P = .005), and pack-years (OR 0.947; CI 0.903-0.993; P = .023) were statistically significant for DNS development.These results indicate that more pack-years smoked were associated with reduced risk of the development of DNS in acute CO poisoning, and that CO exposure time and GCS is a predictive factor for DNS occurrence.

Neuropsychiatric sequelae of acute carbon monoxide poisoning: The predictive role of neuron specific enolase and glial fibrillary acidic protein

BACKGROUND

Acute carbon monoxide (CO) poisoning is one of the most common poisons worldwide and neuropsychiatric sequelae (NS) are the most frequent form of its morbidity.

OBJECTIVES

This study aimed to measure the percentage of patients liable to NS, to evaluate the cognitive profile of patients with NS and to assess the role of neuron specific enolase (NSE) and glial fibrillary acidic protein (GFAP) in predicting the development of NS after acute CO poisoning.

METHODS

This prospective study included 50 patients with acute CO poisoning presented to the Poison Control Center, Ain Shams University Hospitals during the period from beginning of November 2015 till the end of January 2017. Patients' demographic characteristics, clinical manifestations and blood carboxyhemoglobin levels were recorded. Serum levels of NSE and GFAP were determined on admission. Every patient was invited to participate in a follow-up visit at a dedicated outpatient clinic one month after CO exposure. During the visit, a complete neurological examination, as well as a psychiatric evaluation using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders version 4 Axis-I were performed for detection of neurological and psychiatric disorders. Wechsler memory scale test was administrated for detection of cognitive deficits. The patients were divided into two groups based on the presence or absence of NS.

RESULTS

Cognitive impairment was found in 38 % of patients in the NS group. The serum levels of NSE and GFAP were significantly high in the NS group in comparison to the non-NS group. Receiver operating characteristic curves (ROC) determined the cut-off level of NSE at 39 ng/mL achieved 100 % sensitivity with 88.64 % specificity to predict the development of NS after acute CO poisoning while GFAP had 95.24 % sensitivity and 69.23 % specificity at a cut-off value of 2.8 ng/mL.

CONCLUSION

NSE and GFAP could be useful in the early identification of patients at risk of developing NS after CO poisoning helping in treatment plans and thus improving quality of care.

Clinical predictors of delayed neurological sequelae in charcoal-burning carbon monoxide poisoning

BACKGROUND

The main objective of the treatment of acute carbon monoxide (CO) poisoning is to prevent delayed neurological sequelae (DNS). However, today there is still no objective screening tool to identify patients at high risk of developing DNS. The aim of this study was to identify clinical factors that could predict DNS after acute charcoal-burning CO poisoning.

METHODS

This prospective observational study was conducted from September 1, 2019 to August 31, 2020 in a single academic medical center. Patients older than 18 years of age suffering from charcoal-burning CO poisoning were included in the study. After acute recovery, patients were followed up for six weeks to investigate for DNS development. The clinical predictors of DNS were determined using a multivariate logistic regression model.

RESULTS

Of the 217 patients-113 males (52.1%), median age 37.0 (27.5-51.5) years-included, 49 (22.6%) developed DNS. The multivariate logistic regression analysis revealed the independent predictors of DNS as a lower initial Glasgow Coma Scale (GCS) score (adjusted odds ratio (AOR): 0.73, 95% confidence interval (CI): 0.62-0.87), a longer duration of CO exposure (AOR: 2.18, 95% CI: 1.65-2.88), and the presence of acute brain lesions with high signal intensity on diffusion-weighted imaging (AOR: 5.22, 95% CI: 1.50-18.08). The created multivariate regression model predicted DNS development with high accuracy (area under the curve: 0.93, 95% CI: 0.89-0.97).

CONCLUSION

A low initial GCS score, longer exposure to CO and abnormal findings on diffusion-weighted magnetic resonance imaging can assist in the early identification of patients at high risk of DNS development.

Cox regression model of prognostic factors for delayed neuropsychiatric sequelae in patients with acute carbon monoxide poisoning: A prospective observational study

OBJECTIVE

A major challenge for physicians is to identify patients with acute carbon monoxide (CO) poisoning who are likely to develop delayed neuropsychiatric sequelae (DNS). DNS is defined as neuropsychological sequelae that develops after 2-40 days of lucid interval after CO intoxication. Currently, there is no consensus on factors that predict the prognosis of CO poisoning. Thus, the purpose of this study was to identify factors predicting the development of DNS using a Cox regression model.

METHODS

This prospective observational study included 310 CO-poisoned patients admitted to an emergency department in South Korea from July 2017 to February 2020. Demographic, clinical, and laboratory data were analyzed. Kaplan-Meier curves were constructed to estimate the cumulative incidence of DNS. A multivariate Cox regression model was used to identify the main predictors of the development of DNS.

RESULTS

The incidence of DNS was 18.8 %, and the median onset time was 23.7 days (interquartile range, 14-30 days). The Kaplan-Meier survival curve showed that a serum creatine kinase (CK) level > 175.5 U/L and initial Glasgow Coma Scale (GCS) score ≤ 9 were associated with a higher cumulative incidence of DNS (log-rank test; p < 0.01 and p = 0.02, respectively). Cox regression analysis showed that a serum CK level > 175.5 U/L (hazard ratio [HR]: 2.862, 95 % confidence interval [CI]: 1.491-5.496; p < 0.01) and an initial GCS ≤ 9 (HR: 2.081, 95 % CI: 1.048-4.131; p = 0.04) were significant prognostic factors.

CONCLUSION

In acute CO poisoning, an initial GCS score ≤ 9 and serum CK level > 175.5 U/L are significant predictors of DNS development.

Predictive Value and Correlation of Neuron-Specific Enolase for Prognosis in Patients with Coma: A Systematic Review and Meta-Analysis

OBJECTIVE

Coma is the most serious disturbance of consciousness, which affects the life quality of patients and increases the burden of their family. Studies to assess the prognostic value of neuron-specific enolase (NSE) in patients with coma have not led to precise, generally accepted prognostic rules. The study aims to assess the correlation between NSE and prognosis of coma and the predictive value of NSE for clinical prognosis.

METHODS

A search was conducted using PubMed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and WanFang Data from the establishment time of databases to December 2019. This analysis included patients with coma, regardless of how long the coma was. In total, 26 articles were retrieved and included in the review.

RESULTS

The meta-analysis revealed the NSE concentration of patients with coma is significantly higher than that of the control group (standard mean difference = 0.88, 95% confidence interval [CI]: 0.63-1.12, p < 0.05). The pooled sensitivity and specificity of NSE in coma diagnosis was 0.5 (95% CI: 0.39-0.61) and 0.86 (95% CI: 0.71-0.94).

CONCLUSIONS

The NSE concentration of patients with poor coma prognosis is significantly higher than that of the control group. The high NSE concentration is not necessarily a poor prognosis for coma, but low NSE concentration indicates a high probability of a good prognosis for coma.

Cerebral White Matter Lesions on Diffusion-Weighted Images and Delayed Neurological Sequelae after Carbon Monoxide Poisoning: A Prospective Observational Study

Introduction: Carbon monoxide (CO) poisoning can result in delayed neurological sequelae (DNS). Factors predicting DNS are still controversial. This study aims to determine whether acute brain lesions observed using diffusion-weighted magnetic resonance imaging (MRI) following acute CO poisoning are related to the subsequent development of DNS. Methods: This prospective study was conducted on patients with CO poisoning treated at a university hospital in Bucheon, Korea. From August 2016 to July 2019, a total of 283 patients visited the hospital because of CO poisoning. Exclusion criteria included age under 18 years, refusing hyperbaric oxygen therapy, refusing MRI, being discharged against medical advice, being lost to follow-up, having persistent neurological symptoms at discharge, and being transferred from another hospital 24 h after exposure. Results: Of the 154 patients included in the final study, acute brain lesions on MRI (ABLM) were observed in 49 patients (31.8%) and DNS occurred in 30 patients (19.5%). In a logistic regression analysis, lower Glasgow coma scale score and higher exposure time were associated with DNS, and the presence of ABLM in white matter was significantly associated with DNS (OR 6.741; 95% CI, 1.843–24.660; p = 0.004). Conclusion: The presence of ABLM in white matter was significantly related to the occurrence of DNS. Early prediction of the risk of developing DNS through MRI may be helpful in treating patients with CO poisoning.

Does alcohol play the role of confounder or neuroprotective agent in acute carbon monoxide poisoning?

Objectives: This study investigated whether alcohol influences the predictive value of initial blood lactate concentration and Glasgow Coma Scale (GCS) score at presentation for the severity of acute carbon monoxide (CO) poisoning and neurologic outcome in patients with acute CO poisoning. Additionally, whether alcohol has a neuroprotective effect after acute CO poisoning was evaluated.Methods: This retrospective study included 158 patients who presented with acute CO poisoning between January 2017 and July 2018 and had an available blood alcohol content (BAC) at presentation. The baseline characteristics, clinical course during hospitalization and neurologic status at 30 days after acute CO poisoning were collected and compared according to BAC. To account for possible confounding or neuroprotective effects of alcohol, BAC was introduced as a continuous variable and a stratified categorical variable in the analysis.Results: The mean and maximum BAC at presentation were 56.8 mg/dl and 408 mg/dl, respectively, in 158 patients presented at a mean of 1.0 hour after acute CO poisoning. Lactate, adjusted for previously suggested predictors, was not associated with acute CO poisoning severity; however, after additional adjustment with BAC variables, lactate was associated with CO poisoning severity. Initial GCS score was associated with CO poisoning severity during hospitalization and neurologic outcome at 30 days after acute CO poisoning, regardless of BAC adjustment. BAC variables were negatively associated with CO poisoning severity but not neurologic outcome at 30 days.Discussion and conclusion: The severity of CO poisoning should never be predicted based on serum lactate alone without adjusting for BAC. However, the initial GCS score can be used as a predictor of CO poisoning severity and the neurologic outcome at 30 days after acute CO poisoning, regardless of alcohol consumption history. Alcohol does not have a neuroprotective effect on acute CO poisoning. Further study is needed to validate these results.