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

Delayed encephalopathy after acute carbon monoxide poisoning: a case study

Delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) is a relatively rare inflammatory-associated neurometabolic complication. In this article, we present a case report of a 50-year-old male patient with a history of carbon monoxide poisoning. This acute poisoning, although successfully controlled during a stay in the intensive care unit of a local hospital, later led to persistent neurological symptoms. The patient was then treated in the inpatient unit of the rehabilitation clinic, where cognitive deterioration began to develop 20 days after admission. Subsequent examination using EEG and magnetic resonance imaging confirmed severe encephalopathy later complicated by SARS-CoV-2 infection with fatal consequences due to bronchopneumonia. Because currently there are no approved guidelines for the management of DEACMP, we briefly discuss the existing challenges for future studies, especially the application of rational immunosuppressive therapy already in the acute treatment phase of CO poisoning, which could prevent the development of a severe form of DEACMP.

Clinical factors for delayed neuropsychiatric sequelae from acute carbon monoxide poisoning: a retrospective study

Background

Delayed neuropsychiatric sequelae (DNS), which seriously affect the daily lives of patients, are the most common complications of carbon monoxide (CO) poisoning. No uniform screening tool is available for identifying high-risk groups. Therefore, in this study, we aimed to explore whether conventional laboratory indicators and imaging data from primary hospitals could predict the occurrence of DNS.

Methods

This retrospective observational study was conducted in a single-center primary hospital from January 1, 2021 to May 31, 2023. Participants included patients aged >18 years with acute CO poisoning. Patients with complete recovery in the acute phase were followed up by telephone and outpatient visits, and the presence of DNS was determined according to the occurrence of new neurological symptoms within 6 weeks after discharge. We obtained demographic, laboratory, and imaging data from the medical records and performed a univariate analysis. A multivariate logistic regression model was used to identify independent clinical predictors of DNS.

Results

A total of 73 patients were included in the study, of whom 25 (34.2%) developed DNS. Multivariate logistic regression analysis revealed that a longer duration of CO exposure (adjusted odds ratio (AOR): 1.262, 95% confidence interval (CI): 1.069-1.490) and the presence of acute brain lesions on diffusion-weighted imaging (DWI) (AOR: 5.117, 95% CI: 1.430-18.315) were independent risk factors for DNS. Receiver operating characteristic analyses of the duration of CO exposure were performed (area under the curve (AUC): 0.825; 95% CI: 0.731-0.918) with a cut-off value of 5.5 h, and DNS was predicted with a sensitivity of 96% and a specificity of 66.7%.

Conclusion

High cranial DWI signal within 24 h and duration of poisoning longer than 5.5 h are independent predictors of DNS. The predictive effects of conventional laboratory indicators require further standardized and large-sample studies.

Carbon monoxide poisoning: beyond survival - mortality, morbidities, and risk factors, a Turkey sample

Background

We aimed to investigate the effect of poisoning on mortality leading to new morbidities in people who survived the poisoning.

Methods

The descriptive-retrospective study evaluated all carbon monoxide poisoning cases between 2012 and 2022 in the Adiyaman. For the fatality, all cases were followed up through Turkey's death notification system until the end of 2022. One-year health records of cases treated as inpatients in Adiyaman hospitals were analyzed for nine diagnoses. A total of 4,395 carbon monoxide cases, recorded over 11 years, were all noted to be accidental cases.

Results

The rate of carbon monoxide poisoning in Adıyaman was calculated as 63.2 per hundred thousand. A total of 87 (2%) of the cases died. The population's hospitalization rate was 1.71, while the mortality rate was 1.25 in a hundred thousand. Among the cases, the hospitalization rate was 2.7, and the admission to intensive care rate was 1.7. The fatality rate was 6.5% for those hospitalized and 12.2% for those admitted to the intensive care unit. The highest fatality rate was 65.5% in patients aged 65 and above. One out of five morbidities was developed in 8.4% of cases within one year. The fatality rate of those who developed morbidities (40%) was higher than those who did not (5.5%). Being male posed a 1,886-fold risk for mortality, and each increase in age posed a 1,086-fold risk for mortality.

Conclusion

Individuals who had carbon monoxide poisoning should be followed up closely for one year after poisoning due to the possibility of the emergence of new morbidities that increase the risk of mortality.

Prediction of individual mortality risk among patients with chronic obstructive pulmonary disease: a convenient, online, individualized, predictive mortality risk tool based on a retrospective cohort study

Background

Chronic obstructive pulmonary disease (COPD) is a serious condition with a poor prognosis. No clinical study has reported an individual-level mortality risk curve for patients with COPD. As such, the present study aimed to construct a prognostic model for predicting individual mortality risk among patients with COPD, and to provide an online predictive tool to more easily predict individual mortality risk in this patient population.

Patients and methods

The current study retrospectively included data from 1,255 patients with COPD. Random survival forest plots and Cox proportional hazards regression were used to screen for independent risk factors in patients with COPD. A prognostic model for predicting mortality risk was constructed using eight risk factors.

Results

Cox proportional hazards regression analysis identified eight independent risk factors among COPD patients: B-type natriuretic peptide (hazard ratio [HR] 1.248 [95% confidence interval (CI) 1.155-1.348]); albumin (HR 0.952 [95% CI 0.931-0.974); age (HR 1.033 [95% CI 1.022-1.044]); globulin (HR 1.057 [95% CI 1.038-1.077]); smoking years (HR 1.011 [95% CI 1.006-1.015]); partial pressure of arterial carbon dioxide (HR 1.012 [95% CI 1.007-1.017]); granulocyte ratio (HR 1.018 [95% CI 1.010-1.026]); and blood urea nitrogen (HR 1.041 [95% CI 1.017-1.066]). A prognostic model for predicting risk for death was constructed using these eight risk factors. The areas under the time-dependent receiver operating characteristic curves for 1, 3, and 5 years were 0.784, 0.801, and 0.806 in the model cohort, respectively. Furthermore, an online predictive tool, the "Survival Curve Prediction System for COPD patients", was developed, providing an individual mortality risk predictive curve, and predicted mortality rate and 95% CI at a specific time.

Conclusion

The current study constructed a prognostic model for predicting an individual mortality risk curve for COPD patients after discharge and provides a convenient online predictive tool for this patient population. This predictive tool may provide valuable prognostic information for clinical treatment decision making during hospitalization and health management after discharge (https://zhangzhiqiao15.shinyapps.io/Smart_survival_predictive_system_for_COPD/).

Carbon Monoxide Poisoning was Associated With Lifetime Suicidal Ideation: Evidence From A Population-Based Cross-Sectional Study in Hebei Province, China

Objectives: We want to test the association between carbon monoxide poisoning (CMP) experiencing and lifetime suicidal ideation/suicide plan among community residents.

Methods: This is a population-based cross-sectional study conducted among community residents in Hebei province, China. We analyzed a total of 21,376 valid questionnaires. CMP experience and lifetime suicidal ideation/suicide plan were assessed in this study. Logistic regression and false discovery rate correction were conducted to analyze the associations and correct the p values.

Results: We found that CMP (OR = 2.56, p < 0.001, corrected-p = 0.001) was associated with lifetime suicidal ideation, and the other risk factors were female (OR = 0.53, p < 0.001, corrected-p = 0.001). The association between CMP and suicide plan was not supported after false discovery rate correction (OR = 2.15, p = 0.035, corrected-p = 0.385). For the CMP patients, experiencing ≥2 times CMP (OR = 2.76, p = 0.001, corrected-p = 0.011) was also in higher risk of lifetime suicidal ideation. The association between CMP times and lifetime suicidal plan was not supported after false discovery rate correction (OR = 4.95, p = 0.021, corrected-p = 0.231).

Conclusion: CMP patients are in higher risk of lifetime suicidal ideation. For CMP patients, some strategies are needed to control their suicidal ideation.

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.

Association between Early Phase Serum Lactate Levels and Occurrence of Delayed Neuropsychiatric Sequelae in Adult Patients with Acute Carbon Monoxide Poisoning: A Systematic Review and Meta-Analysis

The primary goal of treating carbon monoxide (CO) poisoning is preventing or minimizing the development of delayed neuropsychiatric sequelae (DNS). Therefore, screening patients with a high probability for the occurrence of DNS at the earliest is essential. However, prognostic tools for predicting DNS are insufficient, and the usefulness of the lactate level as a predictor is unclear. This systematic review and meta-analysis investigated the association between early phase serum lactate levels and the occurrence of DNS in adult patients with acute CO poisoning. Observational studies that included adult patients with CO poisoning and reported initial lactate concentrations were retrieved from the Embase, MEDLINE, Google Scholar and six domestic databases (KoreaMED, KMBASE, KISS, NDSL, KISTi and RISS) in January 2022. Lactate values were collected as continuous variables and analyzed using standardized mean differences (SMD) using a random-effect model. The risk of bias was evaluated using the Quality in Prognosis Studies (QUIPS) tool, and subgroup, sensitivity and meta regression analyses were performed. Eight studies involving a total of 1350 patients were included. The early phase serum lactate concentration was significantly higher in the DNS group than in the non-DNS group in adult patients with acute CO poisoning (8 studies; SMD, 0.31; 95% CI, 0.11−0.50; I2 = 44%; p = 0.002). The heterogeneity decreased to I2 = 8% in sensitivity analysis (omitting Han2021; 7 studies; SMD, 0.38; 95% CI, 0.23−0.53; I2 = 8%; p < 0.001). The risk of bias was assessed as high in five studies. The DNS group was associated with significantly higher lactate concentration than that in the non-DNS group.

Association between Glasgow Coma Scale in Early Carbon Monoxide Poisoning and Development of Delayed Neurological Sequelae: A Meta-Analysis

A significant number of people experience delayed neurologic sequelae after acute carbon monoxide (CO) poisoning. The Glasgow Coma Scale (GCS) can be used to predict delayed neurologic sequelae occurrence efficiently and without any restrictions. Here, we investigated the association between a low GCS score observed in cases of early CO poisoning and delayed neurologic sequelae development through a meta-analysis. We systematically searched MEDLINE, EMBASE, and the Cochrane Library for studies on GCS as a predictor of delayed neurologic sequelae occurrence in patients with CO poisoning in June 2021. Two reviewers independently extracted study characteristics and pooled data. We also conducted subgroup analyses for the cutoff point for GCS. To assess the risk of bias of each included study, we used the quality in prognosis studies tool. We included 2328 patients from 10 studies. With regard to patients with acute CO poisoning, in the overall pooled odds ratio (OR) of delayed neurologic sequelae development, those with a low GCS score showed a significantly higher value and moderate heterogeneity (OR 2.98, 95% confidence interval (CI) 2.10−4.23, I2 = 33%). Additionally, in subgroup analyses according to the cutoff point of GCS, the development of delayed neurologic sequelae was still significantly higher in the GCS < 9 group (OR 2.80, 95% CI 1.91−4.12, I2 = 34%) than in the GCS < 10 or GCS < 11 groups (OR 4.24, 95% CI 1.55−11.56, I2 = 48%). An initial low GCS score in patients with early CO poisoning was associated with the occurrence of delayed neurologic sequelae. Additionally, GCS was quickly, easily, and accurately assessed. It is therefore possible to predict delayed neurologic sequelae and establish an active treatment strategy, such as hyperbaric oxygen therapy, to minimize neurological sequelae using GCS.

Predicting scale of delayed neuropsychiatric sequelae in patients with acute carbon monoxide poisoning: A retrospective study

OBJECTIVE

To establish and validate a predictive formula for calculating the possibility of developing delayed neurological sequelae (DNS) after acute carbon monoxide (CO) poisoning to facilitate better decision-making about treatment strategies.

METHODS

This study retrospectively enrolled 605 consecutive patients who had been newly diagnosed with CO poisoning from the Central Hospital of Enshi Prefecture between January 1, 2015 and December 31, 2020. The cohort was randomly divided into two subgroups: the development cohort (n = 104) and validation cohort (n = 44). Univariate analysis and backward elimination of multivariate logistic regression were used to identify predictive factors, and a predictive formula was established. The performance was assessed using the area under the curve (AUC), the mean AUC of five-fold cross-validation, and calibration plots.

RESULTS

The formula included four commonly available predictors: initial GCS score, duration of exposure, CK, and abnormal findings on MRI. We next created a formula to calculate the risk score for developing DNS: Risk score = -4.54 + 3.35 * (Abnormal findings on MRI = yes) - 0.51 * (Initial GCS score) + 0.65 * (Duration of exposure) + 0.01 * (CK). Then, the probability of developing DNS could be calculated: Probability of DNS = 1/(1 + e ^{Risk score}). The model revealed good discrimination with AUC, and mean AUC of fivefold cross-validation in two cohort, and the calibration plots showed good calibration.

CONCLUSIONS

This study established a prediction predictive formula for predicting developing of DNS, which could facilitate better decision-making about treatment strategies.

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.

Analysis of risk factors of delayed encephalopathy after acute carbon monoxide poisoning

Objective:

To analyze the risk factors of delayed encephalopathy in patients with acute carbon monoxide poisoning (DEACMP) and to investigate the clinical significance and clinical value.

Methods:

The baseline data from 68 patients admitted in the 981st Hospital of Chinese People’s Liberation Army Joint Logistics Support Force were collected, including sex, age, Glasgow Coma Scale (GCS), history of smoking/drinking, history of DEACMP. Laboratory examination records including cranial CT/MRI, cervical vascular color ultrasonography, cardiac color ultrasonography, blood biochemical markers, blood routine, and blood coagulation function were also collected. Additionally, patients were followed-up visited at 1 month and 6 months. Patients were divided into either the DEACMP group or the NDEACMP group according to the occurrence of DEACMP. The risk factors of DEACMP were identified by univariate and logistic regression analyses. The area under the curve (AUC), sensitivity, and specificity of each index were compared by the receiver operating characteristic (ROC) curve.

Results:

Among the 68 patients, 13 patients suffered from DEACMP with an incidence of 19.1%. Univariate analysis indicated that there were statistically significant differences in patients’ age, blood glucose, blood glucose/potassium, GCS scores, abnormal cranial CT/MRI, and coma time more than 4 h (P < 0.05). Logistic regression analysis showed that B, SE, Wald, df, P, Exp (B) of GCS score were -0.489, 0.208, 5.55, 1, 0.018 and 0.634, respectively. Overall, GCS score is correlated with DEACMP’s occurrence. ROC curve analysis showed that the sensitivity, specificity, and the AUC of GCS scores were 0.769, 0.873 and 0.843, respectively. The AUC of the indices in descending order are: GCS score, blood glucose, blood glucose/potassium and age.

Conclusion:

GCS score, blood glucose, blood glucose/potassium, and age are useful predictive factors for the occurrence of DEACMP. Among these, GCS score is the most significant predictive factor.