Correlation between Time to Hyperbaric Oxygen Therapy and Delayed Neurological Sequelae in Acute Carbon Monoxide Poisoning Patients.

Carbon monoxide (CO) is one of the most common causes of intoxication. Delayed neurologic sequelae (DNS) have a major impact on prognosis of CO poisoning patients. Hyperbaric oxygen therapy (HBOT) is widely used to treat DNS. However, there is no consensus regarding the optimal timing of HBOT. This prospective study enrolled patients who visited the hospital from November 2019 to October 2022. The cutoff value for the latency to HBOT after CO exposure was determined, and the area under the receiver operating characteristic curve (AUC) was estimated. In total, 167 patients were divided into non-DNS and DNS groups. The initial Glasgow Coma Scale (GCS) score, CO exposure time, latency to HBOT after CO exposure, median length of hospital stay (p < 0.001) and creatine kinase (p = 0.016) showed significant differences. A GCS score ≤ 9 had an odds ratio (OR) of 5.059 (95% confidence interval [CI]: 1.602-15.976, p = 0.006), and latency to HBOT after CO exposure ≥ 200 min had an OR of 18.971 (95% CI: 4.310-83.508, p < 0.001). The AUC was 0.8235 (95% CI: 0.7504-0.8966). A GCS score ≤ 9 and latency to HBOT ≥ 200 min may be significant risk factors for DNS.

Neurological symptoms improved by hyperbaric oxygen therapy in a post-cardiac arrest patient due to carbon monoxide poisoning: a case report.

Background: Carbon monoxide (CO) poisoning and cardiac arrest can cause neurological complications such as mental deterioration and movement disorders through ischemic brain injury. We report a case in which neurological sequelae after cardiac arrest caused by CO poisoning improved after hyperbaric oxygen (HBO2) therapy. Case report: A 43-year-old male visited the hospital with cardiac arrest due to CO poisoning. He developed neurological sequelae including mental deterioration and myoclonus after recovering spontaneous circulation. Anticonvulsant therapy was used after target temperature management but did not have a positive effect on neurological symptoms. However, after HBO2 therapy the patient's neurological symptoms improved, and he was discharged a month later. Conclusion: HBO2 therapy may be considered when neurological sequelae persist after cardiac arrest due to CO poisoning.

Optimal sessions of hyperbaric oxygen therapy in patients with carbon monoxide poisoning: A prospective observational study.

INTRODUCTION: Hyperbaric oxygen (HBO) therapy may be a useful treatment to prevent the development of delayed neuropsychiatric sequelae (DNS) in patients with acute carbon monoxide (CO) poisoning. However, there is no clear consensus regarding the optimal number of HBO therapy sessions in patients with CO poisoning. Here, we compared the development of DNS after 3 and > 3 sessions of HBO therapy in patients with acute CO poisoning. METHODS: This prospective observational study recruited 299 patients with CO poisoning. Demographic and clinical information were obtained, including comorbidities, vital signs, and symptoms. Patients were divided into two groups according to whether they received 3 or > 3 sessions of HBO therapy (3 HBO vs. >3 HBO). A propensity score-matching process was used to balance potential prognostic factors in both groups. RESULTS: Of the 299 patients with acute CO poisoning enrolled in this study, 183 (59.0%) were included in the analysis. Patients were excluded for the following reasons: age < 18 years, not underwent HBO therapy, discharged against medical advice, and loss to follow-up. The overall rate of DNS development was 17.5%. The >3 HBO group had a higher incidence of DNS development compared to the 3 HBO group (36.3% vs. 16.3%; p = 0.09). Propensity score-matching analysis revealed similar incidences of DNS (31.3% vs. 28.1%, respectively; p > 0.99). CONCLUSIONS: There is a critical need to determine the optimal number of HBO therapy sessions for patients with acute CO poisoning. This study showed no difference in DNS development after 3 and > 3 sessions of HBO therapy.

Effect of ethanol in carbon monoxide poisoning and delayed neurologic sequelae: A prospective observational study.

OBJECTIVES: Carbon monoxide (CO) is one of the most common poisoning substances, which causes mortality and morbidity worldwide. Delayed neurologic sequelae (DNS) have been reported to occur from several days to months after exposure to CO. Thus, there is a need for prevention, recognition, and treatment of DNS. Patients with CO poisoning as a component of intentional suicide often also consume ethanol, but there is debate regarding its role in DNS. We explored whether ethanol has a neuroprotective effect in CO poisoning. METHODS: This prospective observational study included patients who visited the emergency department from August 2016 to August 2019 due to CO poisoning. After treatment of acute CO poisoning, patients were interviewed by telephone to ascertain whether DNS had occurred within 2 weeks, 1 month, and 3 months from the time of CO exposure. RESULTS: During the study period, 171 patients were enrolled. 28 patients (16.37%) developed DNS. The initial Glasgow Coma Scale (GCS) scores were 15 (10.5-15) for the non-DNS group and 10 (7-15) for the DNS group (p = 0.002). The ethanol levels were 11.01 ± 17.58 mg/dL and 1.49 ± 2.63 mg/dL for each group (p < 0.001). In multivariate logistic regression analysis, the GCS score had an odds ratio of 0.770 (p < 0.001) and the ethanol level had 0.882 (p < 0.030) for onset of DNS. CONCLUSIONS: Higher ethanol level and higher initial GCS score were associated with lower incidence of DNS. Ethanol could have a neuroprotective effect on the occurrence of DNS in CO poisoning patients.

Hyperbaric Oxygen Therapy Did Not Prevent Delayed Neuropsychiatric Sequelae in a Prospective Observational Study With Propensity Score Matching in 224 Patients With Acute Carbon Monoxide Toxicity.

BACKGROUND: It is important to prevent the development of delayed neuropsychiatric sequelae (DNS) in acute carbon monoxide (CO) intoxication, but no effective treatment has been clearly identified. Hyperbaric oxygen (HBO) therapy is one of the treatment options in acute CO poisoning; however, whether it can prevent the development of DNS is controversial. OBJECTIVES: The purpose of this study is to compare the effectiveness of normobaric oxygen (NBO) and HBO in preventing DNS. METHODS: This prospective observational study was conducted on all patients with CO poisoning admitted to the emergency department of a tertiary hospital from 2016 to 2019. We followed-up patients to determine whether symptoms of DNS occurred at ≤6 months. We matched the propensity score to an equivalent distribution of potential covariates. RESULTS: A total of 224 patients with CO poisoning were enrolled in this study. NBO was used for 26 patients and HBO for 198 patients. DNS occurred in 40 patients. There were significant differences between the NBO and HBO groups in terms of carboxyhemoglobin, loss of consciousness, dizziness, chest pain, hospitalization, and length of hospital stay. The incidence of DNS was 19.2% in the HBO group, which was higher than the 7.7% observed in the NBO group, but the difference was not significant (p = 0.18). After propensity score matching, the incidence of DNS did not differ between the NBO and HBO groups (8.3% vs. 10.4%, p > 0.99). CONCLUSION: There was no difference in the incidence of DNS between groups receiving HBO and NBO in acute CO intoxication.