Demographic characteristics and delayed neurological sequelae risk factors in carbon monoxide poisoning

The neutrophil-to-lymphocyte ratio is associated with the frequency of delayed neurologic sequelae in patients with carbon monoxide poisoning

Delayed neurologic sequelae (DNS) is a common complication in patients with carbon monoxide poisoning (COP). We aimed to investigate the association of the neutrophil-to-lymphocyte ratio (NLR) with the frequency of DNS in COP patients. A total of 371 COP patients were investigated in retrospective and prospective studies. A receiver operator curve (ROC) test was performed to evaluate the ability of the NLR to predict DNS in COP patients. The retrospective study included 288 COP patients, of whom 84 (29.2%) were confirmed to have DNS, and 1 (0.3%) died within 28 days. The NLR in the DNS group was significantly higher than that in the non-DNS group (6.84 [4.22-12.43] vs. 3.23 [1.91-5.60] × 109/L). NLR was a significant predictor of the frequency of DNS [odds ratio (OR): 1.130, 95% confidence interval (CI): 1.030, 1.240] in COP patients. The area under the ROC curve of NLR for predicting DNS was 0.766 (95% CI 0.701, 0.832), and the cut-off value was 3.745 (sensitivity, 83.3%; specificity, 58.8%). The prospective study included 83 COP patients, of whom 19 (22.9%) were confirmed to have DNS, and all patients survived. Moreover, the frequency of DNS in the patients with an NLR ≥ 3.745 was notably higher than that in the patients with an NLR < 3.745 [41.4% (12/29) vs. 13.0 (7/54)]. In conclusion, the NLR was a significant, independent predictor of the frequency of DNS in COP patients.

Atypical Presentation of Carbon Monoxide Poisoning With Aphasia

We present a patient with carbon monoxide poisoning with a single focal neurological deficit. The patient was found by emergency medical services (EMS) to be resting in his truck with a generator running nearby. On arrival, the patient was hemodynamically stable. The patient was aphasic but did not exhibit any other focal or lateralizing deficits. He was able to communicate by writing clearly and coherently on a sheet of paper. His initial carboxyhemoglobin was 29%, confirming the diagnosis of carbon monoxide poisoning. He was treated with 100% O₂ via a non-rebreather mask and regained his speech during his ED (emergency department) course. The patient was ultimately hospitalized for continued oxygen treatment and serial examinations. This case highlights the varied presenting symptoms of carbon monoxide poisoning as well as the importance of including a broad differential diagnosis while working up patients with a focal neurologic deficit.

[Carbon monoxide intoxication-New aspects and current guideline-based recommendations]

Carbon monoxide poisoning is a common and potentially life-threatening intoxication, showing an interindividual variety of unspecific symptoms as well as late neurological and other sequelae. Two new German guidelines (S2k guidelines diagnosis and treatment of carbon monoxide poisoning as well as S3 guidelines oxygen therapy in the acute care of adult patients) focus on current evidence-based information on diagnostics as well as therapeutic options with considerable uncertainty remaining. This review summarizes current information and presents a flow scheme for daily practical use.

Neurological sequelae in acute carbon monoxide poisoning: A prospective observational study with MRI data

OBJECTIVES

Acute carbon monoxide (CO) poisoning survivors may experience persistent neurological sequelae (PNS) and delayed neurological sequelae (DNS). This study evaluated the clinical features, laboratory results, acute brain lesions (ABLs) on diffusion-weighted imaging (DWI) at presentation, and long-term outcomes and explored differences between patients with PNS and DNS.

METHODS

The study included 443 patients who had experienced CO poisoning, underwent DWI and completed 1-year follow-ups. The demographics, comorbidities, symptomatology, laboratory results, ABLs on DWI at presentation, and long-term outcomes were compared between patients with PNS and those with DNS.

RESULTS

The 42 (9.5%) and 96 (21.7%) patients with PNS and DNS, respectively, showed no significant differences in demographics, duration of CO exposure, initial conscious level, symptomatology, and laboratory results. ABLs on DWI were observed in 33 patients (33/42) with PNS and 62 patients (62/96) with DNS. The most common region of ABLs was the globus pallidus (60.6% and 56.6% in PNS and DNS, respectively). The proportion of ABLs present and lesion distribution did not differ significantly between the two groups. At 1 year, a significantly higher proportion of patients in the PNS group showed a good outcome (defined as modified Rankin Scale [mRS] scores of 0-2, 81%) compared with the DNS group (81% vs. 56.3%, p = .047).

CONCLUSION

Demographics, clinical features, laboratory results, and acute brain lesions on MRI at presentation did not differ between the PNS and DNS groups. However, the long-term outcome of PNS was better than that of DNS.

Predictive Value of Gray-Matter-White-Matter Ratio on Brain Computed Tomography for Delayed Encephalopathy after Acute Carbon Monoxide Poisoning: A Retrospective Cohort Study

Background

This study is aimed at determining the predictive value of the gray-matter–white-matter ratio (GWR) on brain computed tomography for delayed encephalopathy after acute carbon monoxide (CO) poisoning (DEACMP).

Methods

This retrospective cohort study reviewed 352 patients with acute CO poisoning and who underwent the brain computed tomography test. These patients were admitted to Cangzhou Central Hospital from May 2010 to May 2020. The patients were divided into the DEACMP (n = 16) and non-DEACMP (n = 336) groups. Pearson's correlation coefficients were computed for correlation analysis. The predictive value of GWR for DEACMP was evaluated by using logistic regression analysis and receiver operator characteristic curves.

Results

The morbidity of DEACMP was 4.5% (16/352). The GWR-basal ganglia, GWR-cerebrum, and GWR-average in the DEACMP group were lower than those in the non-DEACMP group. Correlation analysis indicated that GWR-basal ganglia (r = 0.276; P < 0.001), GWR-cerebrum (r = 0.163; P = 0.002), and GWR-average (r = 0.200; P < 0.001) were correlated with DEACMP. Multivariate logistic regression analysis revealed that reduced GWR-basal ganglia, GWR-cerebrum, and GWR-average were independent risk factors (P < 0.001; P = 0.008; P = 0.001; respectively). Compared with GWR-cerebrum and GWR-average, GWR-basal ganglia had a higher area under the curve of 0.881 (95% confidence interval: 0.783–0.983) with sensitivity and specificity of 93.8% and 68.7%, respectively. The cut-off value of GWR-basal ganglia was 1.055.

Conclusion

GWR, especially GWR-basal ganglia, is an early useful predictor for DEACMP.

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.