Purpose: No consensus currently exists regarding the maximal pressure of hyperbaric oxygen (HBO2) therapy performed within 24 hours of acute carbon monoxide (CO) poisoning. This study aimed to evaluate the difference in therapeutic effects according to the first HBO2 pressure (3.0 atmospheres absolute [ATA] vs. 2.8 ATA).
Methods We used prospectively collected registry data on CO poisoning at a tertiary academic hospital in the Republic of Korea. Adult patients with acute CO poisoning treated with HBO2 within 24 hours after arrival at the emergency department and without the use of additional HBO2 after 24 hours between January 2007 and February 2022 were included. Data from 595 patients were analyzed using propensity score matching (PSM). Patients with mild (non-intubated) and severe (intubated) poisoning were also compared. Neurocognitive outcomes at 1 month after CO poisoning were evaluated using the Global Deterioration Scale combined with neurological impairment.
Results After PSM, the neurocognitive outcomes at 1-month post-CO exposure were not significantly different between the 2.8 ATA (110 patients) and 3.0 ATA (55 patients) groups (p=1.000). Similarly, there was also no significant difference in outcomes in a subgroup analysis according to poisoning severity in matched patients (165 patients) (mild [non-intubated]: p=0.053; severe [intubated]: p=1.000).
Conclusion Neurocognitive sequelae at 1 month were not significantly different between HBO2 therapy pressures of 2.8 ATA and 3.0 ATA in patients with acute CO poisoning. In addition, the 1-month neurocognitive sequelae did not differ significantly between intubated and non-intubated patients.
Purpose: This study investigated the differences between patients with acute carbon monoxide (CO) poisoning who visited the emergency department (ED) before and during the coronavirus disease 2019 (COVID-19) pandemic.
Methods This was a single-center retrospective observational study. Patients with CO poisoning who visited the ED during the period from February 2020 to January 2023 were classified as the COVID-19 pandemic group, and those from February 2019 to January 2020 were classified as the non-pandemic group. Patients’ medical records were reviewed, their demographic and clinical characteristics were compared, and the length of stay in ED was checked. The time from admission to the ED to the start of hyperbaric oxygenation (HBO) was defined as the door-to-HBO time, and this parameter was compared between both groups.
Results In total, 672 patients were included in this study. The proportion of intentional poisoning was significantly higher in the COVID-19 pandemic group than in the non-pandemic group (p=0.028). The proportion of intentional poisoning significantly increased in the 20- to 29-year-old age group during the COVID-19 pandemic (p<0.001). In addition, it took longer to initiate HBO in the COVID-19 pandemic group than in the non-pandemic group (p=0.001).
Conclusion These findings suggest that pandemics of infectious diseases, such as COVID-19, increase the proportion of intentional CO poisoning, and it may take longer to initiate HBO after visiting the ED. Efforts will be needed to decrease intentional CO poisoning and length of stay in ED.
Purpose: The purpose of this study was to determine whether deoxyhemoglobin changes were associated with admission duration in carbon monoxide (CO)-poisoned patients.
Methods This retrospective study included 181 patients who were able to breathe by themselves after CO poisoning. Arterial blood gas analysis was performed to measure their deoxyhemoglobin levels. Their baseline characteristics and clinical outcomes during hospitalization in the emergency department (ED) were collected and compared. To assess changes in deoxyhemoglobin levels, blood samples were taken immediately after patients presented to the ED and then again after 6 hours. For statistical analysis, logistic regression was utilized to determine the effect of deoxyhemoglobin changes on admission duration.
Results The incidence rates of hypocapnia and hypoxemia at presentation after acute CO poisoning were 28.7% and 43.6%, respectively. Moreover, the magnitude of increasing deoxyhemoglobin levels in patients with hypoxemia (2.1 [1.7–3.1], p<0.001) and changes in deoxyhemoglobin levels appeared to have an impact on the length of hospitalization in the ED (odds ratio, 1.722; 95% confidence interval, 0.547–0.952; p<0.001).
Conclusion In patients with acute CO poisoning, deoxyhemoglobin levels appeared to increase in those with hypoxemia, which in turn was associated with prolonged hospitalization.
Purpose: The purpose of this study was to investigate effect of N-acetylcysteine (NAC) on the injury of putative parvalbumin positive interneurons defined by molecular marker and hippocampal long-term potentiation (LTP), a marker of neural plasticity following acute carbon monoxide (CO) poisoning. Methods: Adult Sprague-Dawley rats were exposed to 1100 ppm CO for 40 minutes followed by 3000 ppm CO for 20 minutes. Animals received daily intraperitoneal injection of NAC (150 mg/kg) for 5 days after CO exposure. Changes in learning and spatial memory were evaluated by Y-maze test 5 days after the poisoning. In vivo LTP in hippocampal CA1 area was evaluated by using extracellular electrophysiological technique. Immunohistochemical staining were adopted to observe expressional damages of parvalbumin (PV) immunoreactive interneurons in the hippocampus following the poisoning. Results: Acute CO intoxication resulted in no changes in memory performance at Y-maze test but a significant reduction of LTP in the in hippocampal CA1 area. There was also a significant reduction of PV (+) interneurons in the hippocampal CA1 area 5 days after CO poisoning. Daily treatment of NAC significantly improved hippocampal LTP impairment and reduced immunoreactivity for PV in the hippocampus following the acute CO poisoning. Conclusion: The results of this study suggest that reduction of hippocampal LTP and PV (+) interneurons in the hippocampus is sensitive indicator for brain injury and daily NAC injections can be the alternative therapeutics for the injury induced by acute CO poisoning.
Purpose: This study evaluated aggressive hyperbaric oxygen therapy (HBOT) by understanding various exposure routes of acute carbon monoxide (CO) poisoning, the risk factors causing acute cardiovascular, and neurological toxicity caused by poisoning. Methods: A retrospective study was conducted based on the medical records of 417 acute CO poisoning patients who visited the emergency care unit from March 2017 to August 2019. The exposure routes, HBOT performance, age, sex, medical history (hypertension, diabetes mellitus, ischemic heart disease, heart failure), intentionality, loss of consciousness (LOC), intake with alcohol or sedatives, and initial test results (carboxyhemoglobin (COHb), troponin-I, electrocardiography, echocardiography, brain MRI) were examined. Comparative analysis of the clinical information was conducted between the groups that showed acute cardiovascular toxicity and neurological toxicity, and groups that did not. Results: Among 417 patients diagnosed with acute CO poisoning, 201 cases (48.2%) were intentional, and charcoal briquette was the most common route (169 patients (40.5%)). Two hundred sixteen cases (51.8%) were accidental, and fire was the most common route (135 patients (32.4%)). The exposure route was more diverse with accidental poisoning. Three hundred ninety-nine patients were studied for acute cardiovascular toxicity, and 62 patients (15.5%) were confirmed to be positive. The result was statistically significant in intentionality, LOC, combined sedatives, initial COHb, HTN, and IHD. One hundred two patients were studied for acute neurological toxicity, which was observed in 26 patients (25.5%). The result was statistically significant in age and LOC. Conclusion: Active HBOT should be performed to minimize damage to the major organs by identifying the various exposure routes of CO poisoning, risk factors for acute cardiovascular toxicity (intentionality, LOC, combined sedatives, initial COHb, HTN, IHD), and the risk factors for acute neurological toxicity (age, LOC).
Purpose: We studied the impact of arterial oxygen tension (PaO2) on the long term neurologic outcome in patients with acute carbon monoxide poisoning. Methods: The study population included 311 patients who presented to emergency department with acute CO poisoning from January 2015 to January 2018. These patients underwent arterial blood gas testing at the time of presentation. The baseline demographic, clinical, laboratory, and clinical outcome data were recorded. The primary outcome of interest was the long term neurologic status. Results: The normoxia group was significantly older and it had a higher incidence of diffusion weighted MRI abnormality, and this group needed multiple HBO sessions compared to the group with moderate or severe hyperoxia. Also, the incidence of altered mentality at discharge was higher in the normoxia group than that of the moderate hyperoxia group. The incidence of a poor long term neurologic outcome was 11.3%. The incidence of a poor long term neurologic outcome decreased as the PaO2 increased. The PaO2 was significantly lower in patients with a poor long term neurologic outcome than that of the patients with a good outcome 198 (165.2 to 231.1) mmHg in the good outcome group vs. 154 (119-162) mmHg in poor outcome, p<0.001). In multivariate logistic regression analysis, PaO2 was selected as an independent factor of the poor long-term neurologic outcome (OR 0.981 (95% CI: 0.968 to 0.995)) Conclusion: Higher PaO2 was independently associated with a lower incidence of a poor long-term neurologic outcome.
Purpose: The objective was to determine the association between PaCO2 and adverse cardiovascular events (ACVEs) in carbon monoxide (CO)-poisoned patients. Methods: This retrospective study included 194 self-breathing patients after CO poisoning with an indication for hyperbaric oxygen therapy and available arterial blood gas analysis at presentation and 6 hours later. The baseline characteristics and clinical course during hospitalization were collected and compared. The mean PaCO2 during the first 6 hours after presentation was calculated. Results: The incidence rates of moderate (30 mmHg< PaCO2 <35 mmHg) or severe (PaCO2 ≤30 mmHg) hypocapnia at presentation after acute CO poisoning were 40.7% and 26.8%, respectively. The mean PaCO2 during the first 6 hours was 33 (31-36.7) mmHg. The incidence of ACVEs during hospitalization was 50.5%. A significant linear trend in the incidence of ACVEs was observed across the total ranges of PaCO2 variables. In multivariate regression analysis, mean PaCO2 was independently associated with ACVEs (OR 0.798 (95% CI 0.641-0.997)). Conclusion: Mean PaCO2 during the first 6 hours was associated with increased ACVEs. Given the high incidence of ACVEs and PaCO2 derangement and the observed association between PaCO2 and ACVEs, this study suggests that 1) PaCO2 should be monitored at the acute stage to predict and/or prevent ACVEs; and 2) further study is needed to validate this result and investigate early manipulation of PaCO2 as treatment.
Purpose: Acute carbon monoxide (CO) poisoning is one of the most common types of poisoning and a major health problem worldwide. Treatment options are limited to normobaric oxygen therapy, administered using a non-rebreather face mask or hyperbaric oxygen. Compared to conventional oxygen therapy, high-flow nasal cannula oxygen (HFNC) creates a positive pressure effect through high-flow rates. The purpose of this human pilot study is to determine the effects of HFNC on the rate of CO clearance from the blood, in patients with mild to moderate CO poisoning. Methods: CO-poisoned patients were administered 100% oxygen from HFNC (flow of 60 L/min). The fraction of COHb (fCOHb) was measured at 30-min intervals until it decreased to under 10%, and the half-life time of fCOHb (fCOHb t1/2) was subsequently determined. Results: At the time of ED arrival, a total of 10 patients had fCOHb levels ≥10%, with 4 patients ranging between 10% and 50%. The mean rate of fCOHb elimination patterns exhibits logarithmic growth curves that initially increase quickly with time (HFNC equation, Y=0.3388*X+11.67). The mean fCOHbt1/2 in the HFNC group was determined to be 48.5±12.4 minutes. Conclusion: In patients with mild to moderate CO poisoning, oxygen delivered via high flow nasal cannula is a safe and comfortable method to treat acute CO toxicity, and is effective in reducing the COHb half-life. Our results indicate HFNC to be a promising alternative method of delivering oxygen for CO toxicity. Validating the effectiveness of this method will require larger studies with clinical outcomes.
Purpose: This study examined the association between smoking and delayed neuropsychological sequelae (DNS) in acute carbon monoxide (CO) poisoning. Methods: Patients admitted to the medical center emergency department from March 2016 to March 2017 because of CO poisoning were examined retrospectively. The patients were divided into two groups: DNS and Non-DNS group. Multiple factors were analyzed to explain DNS, which was assessed by motor disturbances, cognitive impairment, dysphagia, Parkinson-like syndromes, epilepsy, and emotional lability in CO poisoning. Results: A total of 120 patients were included. The factors related to DNS were smoking (pack-years) (p=0.002) and initial carbon monoxide-hemoglobin level (p=0.015). On the other hand, after multivariate logistic regression analysis, smoking (Odds ratio 1.07; 95% CI, 1.02-1.13; p=0.004) was the only factor associated with DNS. Conclusion: Smoking is a very reliable factor for predicting the occurrence of DNS. A history of smoking in patients who suffer from CO intoxication is important. If a patient smokes, treatment should be started actively and as soon as possible.
Purpose: This study was conducted to describe the characteristics of patients with carbon monoxide (CO) poisoning. Methods: We retrospectively surveyed data from the Emergency Department based Injury In-depth Surveillance of 20 hospitals (2011-2014). We included patients whose mechanism of injury was acute CO poisoning caused by inhalation of gases from charcoal or briquettes. We surveyed the annual frequency, gender, age, result of emergency treatment, rate of intensive care unit (ICU) admission, result of admission, association with alcohol, and place of accident. We also surveyed the cause and experience of past suicide attempts by intentional poisoning. Results: A total of 3,405 patients were included (2,015 (59.2%) and 1,390 (40.8%) males and females, respectively) with a mean age of $39.83{pm}18.51$ year old. The results revealed that the annual frequency of CO poisoning had increased and the frequency of unintentional CO poisoning was higher than that of intentional CO poisoning in January, February and December. The mean age of intentional CO poisoning was younger than that of unintentional CO poisoning ($38.41{pm}13.03$ vs $40.95{pm}21.83$) (p<0.001). The rates of discharge against medical advice (DAMA), ICU care and alcohol association for intentional CO poisoning were higher than for unintentional CO poisoning (36.4% vs 14.0%, 17.8% vs 4.7%, 45.2% vs 5.6%) (p<0.001). The most common place of CO poisoning was in one's residence. Conclusion: The annual frequency of total CO poisoning has increased, and unintentional CO poisoning showed seasonal variation. DAMA, ICU care, and alcohol association of intentional CO poisoning were higher than those of unintentional CO poisoning.
Citations
Citations to this article as recorded by
Prevalence of Carbon Monoxide Poisoning and Hyperbaric Oxygen Therapy in Korea: Analysis of National Claims Data in 2010–2019 Eunah Han, Gina Yu, Hye Sun Lee, Goeun Park, Sung Phil Chung Journal of Korean Medical Science.2023;[Epub] CrossRef
Purpose: Because carbon monoxide (CO)-intoxicated patients with an alert mental status and only mild cognitive dysfunction may be inadequately assessed by traditional bedside neurologic examination in the emergency department (ED), they may not receive appropriate treatment. Methods: We retrospectively investigated the incidence and features of cognitive dysfunction using the Korean version of the Mini-Mental State Examination (MMSE-K) in ED patients with CO poisoning with alert mental status. We conducted a retrospective review of 43 consecutive mild CO poisoned patients with a Glasgow Coma Scale score of 15 based on documentation by the treating emergency physician in the ED between July 2014 and August 2015. Results: Cognitive dysfunction, defined as a score of less than 24 in the MMSE-K, was diagnosed in six patients (14%) in the ED. In the MMSE-K, orientation to time, memory recall, and concentration/calculation showed greater impairments. The mean age was significantly older in the cognitive dysfunction group than the non-cognitive dysfunction group (45.3 yrs vs. 66.5 yrs, p<0.001). Among the initial symptoms, experience of a transient change in mental status before ED arrival was significantly more common in the cognitive dysfunction group (32.4% vs. 100%, p=0.003). Conclusion: Patients with CO poisoning and an alert mental status may experience cognitive dysfunction as assessed using the MMSE-K during the early stages of evaluation in the ED. In the MMSE-K, orientation to time, memory recall, and concentration/calculation showed the greatest impairment.
Purpose: The aim of this study was to evaluate the cardiovascular manifestations and clinical course in patients with acute carbon monoxide poisoning. Methods: A retrospective study was conducted over a 36 month period on consecutive patients who visited an emergency medical center and were diagnosed with acute carbon monoxide poisoning. A standardized data extraction protocol was performed on the selected patients. Results: A total of 293 patients were selected during the study period. Cardiac manifestations were observed in 35.2% (n=103) of the patients: hypotension in 11 patients (3.8%), ECG abnormalities in 44 patients (15.0%) and cardiac enzyme abnormalities in 103 patients (35.2%). Echo cardiography was performed on 56 patients with cardiac toxicity: 12 patients had abnormal results (5 patients with global hypokinesia and 7 patients with regional wall akinesia). Five patients died within 3 hours after ED admission, and the remaining patients were discharged alive. At 3 months after discharge, none of these patients had died.The SOFA scores in the severe cardiac toxicity group and non-severe cardiac toxicity group at the time of arrival were $2.53{pm}2.29$ and $2.19{pm}2.12$, respectively (p=0.860). Conclusion: Cardiovascular manifestations occur after acute CO poisoning at arateof 35.2%. Even those with severe cardiovascular toxicity recovered well within 10 days after admission. Therefore, the importance of cardiac toxicity after acute CO poisoning is not significant in itself in the clinical course, and the short-term prognosis of cardiac toxicity is unlikely to be unfavorable in acute CO poisoning.
Min Ki Cho, Yang Weon Kim, Kyeong Ryong Lee, Kyung Woo Lee, Jang Young Lee, Gyu Chong Cho, Junho Cho, Hyun Jong Kim, Seong Hwan Kim, Sung Phil Chung, Hahn Shick Lee
J Korean Soc Clin Toxicol. 2012;10(2):73-79. Published online December 31, 2012
Purpose: The purpose of this study was to identify the changes in the characteristics of patients with carbon monoxide (CO) poisoning, as well as the distinctive differences in intentionally exposed patients. Methods: The medical records of CO poisoning patients, who visited nine emergency departments between January 2010 and December 2011, were reviewed retrospectively. The clinical information including age, gender, hospitalization, type of discharge, cause and location of exposure, site of onset, concentration of initial blood carboxyhemoglobin (COHb), methods of treatment and presence of neurological complications was examined. The subjects were divided into an intentional and non-intentional group and the differences between them was compared. Results: A total 209 subjects were recruited. The median age was 38 years (29~49.5 years). They frequently complained of nausea and vomiting, and the most common exposures occurred in winter, normally in the home. The cause of exposure was usually fire, followed by incomplete combustion of fuels. The median initial blood COHb was 13.15%. The proportion of intentionally exposed patients was 21%. They were significantly younger, more frequently discharged against medical advice, and showed a higher initial blood COHb level (22.85%) than the non-intentional group. Conclusion: This study suggests that those with intentional CO poisoning are normally discharged against medical advice even when they have a higher initial COHb level. An adequate explanation of the delayed neurologic sequelae and short term follow-up observation is recommended for those patients with intentional exposure.
Purpose: The aim of this study was to describe the epidemiologic characteristics of adult patients with carbon monoxide poisoning who presented to the emergency department in recent years. Methods: This was a retrospective cohort study on adult consecutive patients with carbon monoxide (CO) poisoning who presented to the emergency department of a tertiary care university-affiliated hospital from January 1, 2008 to December 31, 2011. Results: A total of 91 patients were included in this study; there were 56(61.5%) unintentional and 35(38.5%) intentional poisonings. For the unintentional CO poisonings, the principal sources of exposure to CO were fire (39.3%), charcoal (17.9%), briquette charcoal (7.1%), wood burning boiler (7.1%), gas boiler (5.4%), automobile heater (3.6%), briquette boiler (3.6%), firewood (3.6%), and other items (12.5%). For the intentional CO poisonings, the sources were ignition charcoal (60.0%), briquette (31.4%), charcoal (5.7%) and butane gas (2.9%). For the unintentional CO poisonings, the places of poisoning were the home (58.9%), workplace (10.7%), public accommodation (8.9%), tent (8.9%), automobile (3.6%) and parking place (1.8%). For the intentional CO poisonings, the places of poisoning were the home (77.1%), public accommodation (11.4%) and automobile (11.4%). The proportion of intentional CO poisonings among total poisonings has increased significantly in recent years; 0.0% in 2008, 3.3% in 2009, 5.5% in 2010, and 29.7% in 2011. Conclusion: This study showed that in recent years in Korea, the source of CO has diversified broadly and intentional CO poisonings from burning ignition charcoal or briquettes has increased. Prevention efforts should consider these factors.
Purpose: Suicide attempts are known to be influenced by mass media reports. The purpose of this study was to evaluate the effects of mass media reporting celebrity suicides on an increase of intentional carbon monoxide (CO) poisoning and suicide attempts. Methods: We retrospectively reviewed the medical records of the consecutive patients who presented with suicide attempts to the Emergency Department of Ajou University Hospital during a 24 month period. We obtained the demographic data, any past history of suicide attempt and the methods of suicide attempts from the medical records of the suicide attempters. Time series analysis was conducted for evaluating the influence of mass media reporting of celebrity suicide on the suicide rates. Results: We finally enrolled 770 patients during the study period. The total number of suicide attempts by CO poisoning was 18 and the average number of suicide attempts by CO was $0.33{pm}0.73$ per week. All of the suicide attempts by CO poisoning occurred after a celebrity committed suicide using CO from burning charcoal. Conclusion: This study showed that celebrity suicide by CO poisoning resulted in the Werther effect, which made the rate of intended CO poisoning increase, and the study provided further evidence for the need to actively restrain mass media reporting of suicide to decrease the Werther effect.