Carboxyhemoglobin Levels Research Articles

Carboxyhemoglobin (COHb): Unavoidable Bystander or Protective Player?

Carbon monoxide (CO) is a cytoprotective endogenous gas that is ubiquitously produced by the stress response enzyme heme-oxygenase. Being a gas, CO rapidly diffuses through tissues and binds to hemoglobin (Hb) increasing carboxyhemoglobin (COHb) levels. COHb can be formed in erythrocytes or in plasma from cell-free Hb. Herein, it is discussed as to whether endogenous COHb is an innocuous and inevitable metabolic waste product or not, and it is hypothesized that COHb has a biological role. In the present review, literature data are presented to support this hypothesis based on two main premises: (i) there is no direct correlation between COHb levels and CO toxicity, and (ii) COHb seems to have a direct cytoprotective and antioxidant role in erythrocytes and in hemorrhagic models in vivo. Moreover, CO is also an antioxidant by generating COHb, which protects against the pro-oxidant damaging effects of cell-free Hb. Up to now, COHb has been considered as a sink for both exogenous and endogenous CO generated during CO intoxication or heme metabolism, respectively. Hallmarking COHb as an important molecule with a biological (and eventually beneficial) role is a turning point in CO biology research, namely in CO intoxication and CO cytoprotection.

Accuracy of pulse CO-oximetry to evaluate blood carboxyhemoglobin level: a systematic review and meta-analysis of diagnostic test accuracy studies.

Carbon monoxide (CO) poisoning is one of the most common causes of poisoning death and its diagnosis requires an elevated carboxyhemoglobin (COHb) level. Noninvasive CO saturation by pulse oximetry (SpCO) has been available since 2005 and has the advantage of being portable and easy to use, but its accuracy in determining blood COHb level is controversial. To evaluate the accuracy of SpCO (index test) to estimate COHb (reference test). Systematic review and meta-analysis of diagnostic test accuracy (DTA) studies. Four electronic databases were searched (Medline, Embase, Cochrane Central Register of Controlled Trials, and OpenGrey) on 2 August 2022. All studies of all designs published since the 2000s evaluating the accuracy and reliability of SpCO measurement compared to blood COHb levels in human volunteers or ill patients, including children, were included. The primary outcome was to assess the diagnostic accuracy of SpCO for estimating COHb by blood sampling by modeling receiver operating characteristic (ROC) curves and calculating sensitivity and specificity (primary measures). The secondary measures were to calculate the limits of agreement (LOA) and the mean bias. This systematic review was conducted according to the Preferred Reporting Items for a Systematic Review and Meta-analysis-DTA 2018 guidelines and has been registered on International Prospective Register of Systematic Reviews (CRD42020177940). The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Twenty-one studies were eligible for the systematic review; 11 could be included for the quantitative analysis of the primary measures and 18 for the secondary measures. No publication bias was found. The area under the summary ROC curve was equal to 86%. The mean sensitivity and specificity were 0.77, 95% confidence interval (CI, 0.66-0.85) and 0.83, 95% CI (0.74-0.89), respectively (2089 subjects and 3381 observations). The mean bias was 0.75% and the LOA was -7.08% to 8.57%, 95% CI (-8.89 to 10.38) (2794 subjects and 4646 observations). Noninvasive measurement of COHb (SpCO) using current pulse CO oximeters do not seem to be highly accurate to estimate blood COHb (moderate sensitivity and specificity, large LOA). They should probably not be used to confirm (rule-in) or exclude (rule-out) CO poisoning with certainty.

Elevated methemoglobin levels in patients treated with high-dose hydroxocobalamin.

The aim of this study was to assess the impact of hydroxocobalamin (OHCbl) infusion on arterial blood gas and oximetry values in patients with vasoplegic syndrome. Blood samples collected from 95 patients receiving OHCbl infusion were assayed using the ABL90 FLEX Plus blood gas analyzer for the concentration of methemoglobin (MetHb), total hemoglobin (tHb), carboxyhemoglobin (COHb), arterial oxygen saturation (SaO2), arterial oxygen partial pressure (PaO2), and arterial carbon dioxide partial pressure (PaCO2). Interference of OHCbl on these variables was evaluated using the measured difference between the preinfusion and postinfusion samples. Blood MetHb (%) measured after the infusion of OHCbl (5g) were significantly higher than the baseline levels, with a median of 4.8 (IQR, 3.0-6.5) versus 1.0 (IQR, 1.0-1.2) (P < .001). Blood COHb (%) increased from a median of 1.3 (IQR, 1.0-1.8) to 1.7 (IQR, 1.3-2.2) (P < .001) following the OHCbl infusion. No differences were seen in median levels of tHb, PaO2, PaCO2, and SaO2 between pre- and post-OHCbl treatment. The presence of OHCbl in blood clearly interfered with the oximetry measurements of the hemoglobin component fractions by falsely increasing the levels of MetHb and COHb. Blood levels of MetHb and COHb cannot be reliably determined by the co-oximetry when OHCbl is known or suspected.

Carbon monoxide poisoning cases in the emergency department are increasing in the last decade in Jerusalem.

The aim of our study was to describe the epidemiology of Carbon monoxide poisoning in the Emergency Department. A retrospective descriptive analysis of patients with Carbon monoxide poisoning who were presented to the Emergency Department of Hadassah hospital in Jerusalem from 2007 to 2016. All patients that were included are confirmed cases [carboxyhemoglobin level > 5%]. Sources of exposure, seasonal variation, and demographic characteristics were analyzed. There were 244 patients (60% males) with 37 family clusters that accounted for 135 (55.3%) patients. One hundred seventy-three (70.9%) patients presented during the winter months. The main sources of exposure were: non-gas residential heating system, mainly charcoal grills and kerosene stoves (n = 100, 41%). Other sources were fires (n = 70, 28.7%), faulty gas heater (n = 34, 13.9%) and smoking (n = 15, 6.1%). The estimated annual incidence increased from an average of 20.8 cases a year between 2007-2011 to an average of 34 cases in 2011-2016. High-risk poisoning (levels > 25%) occurred in 28 patients (11.5%). Factors associated with severe poisoning were female gender and exposure in clusters compared with individual patients. Our current study has showed an increase of Carbon Monoxide poisoning in contrary to our study performed in the previous decade. Fortunately, we did find a lower rate of cases with severe poisoning. Beside the implementation of safer standards for residential heating systems, customized public education is advised in order to lower rates of poisoning in the future. A predicted heavy snow fall should be considered a trigger for a public health warning regarding the risk of CO poisoning.

508 Retrospective Review of Early Pulmonary Mechanics After Inhalation Injury

Abstract Introduction Management of inhalation injury is largely supportive and consists primarily of mechanical ventilation, bronchodilators, muscarinic receptor antagonists, and inhaled mucolytics and anticoagulants. The purpose of this study is to examine the early changes in pulmonary mechanics after inhalation injury and see if the use of NT affects lung function. Methods Retrospective study was done on Inhalation injury patients over a 12 years period from 01/2009 to 01/2021. Patients’ data collected from their medical records, included patient demographics and outcomes, percentage Total Body Surface Area (TBSA), Carboxyhemoglobin level upon admission, Respiratory Treatments (bronchodilator, Mucolytic and Heparin), Tobramycin treatment, Oxygen requirement, Lung compliance (peak airway pressure &amp; Mean airway Pressure), Mode of Ventilation, total Ventilator Day, and number of Hospital Days. Patients with inhalation injury from 2009-2019 were retrospectively reviewed for treatment of inhalation injury. Univariate analysis and multiple logistic regression were performed using Excel and Stata. Results Of 90 patients with inhalation injury, median age was 53.5 (IQR:31-65) with 30% (n=28) women and median TBSA of 15%(IQR:2-38%). The median length of stay was 21 days (IQR:6-47). Median ventilator days was (8.5, IQR:3-21) and median ICU days was 12 (IQR:3-28). After adjusting for grade of inhalation injury, patients who did not receive NT were 2.7 times as likely to get pneumonia compared to patients who received NT (p=0.037). Initial median carboxyhemoglobin was 3.9 (IQR: 2-9.1). Overall mortality was 21%, but the incidence of death increased with grade of injury The Median Mean Airway Pressures were Day 1: 9.5mmHg, Day 2: 11mmHg, Day 3: 13mmHg, Day 4: 12mmHg The median peak pressures were Day 1; 20mmHg, Day 2: 21mmHg; Day 3: 22.5mmHg; Day 4: 21mmHg Conclusions Patients with inhalation injury are susceptible to Acute Respiratory Distress Syndrome, indicated by a decrease in lung compliance and increase in the patient’s oxygenation support. The lung compliance of these patients being to change resulting in an increase in their Peak Airway Pressure and Mean Airway Pressure within the first 72 hours. Moderate hypoxemia is present in these patients with the progress of the smoke inhalation injury. The usage of NT did not have a direct benefit to the pulmonary mechanics for inhalation injury when used as a prophylactic strategy. Additional research and clinical trials are needed to better understand the effect of inhalation injury on pulmonary mechanics. Applicability of Research to Practice Analysis of pulmonary mechanics in patients with inhalation injury can allow clinicians to better tailor ventilator settings to improve clinical outcomes.

Use of CO-oximetry to confirm carboxyhemoglobinemia in cats involved in secondary arson homicide.

The body of a deceased human and 4 deceased cats were found in a house while a fire was being extinguished. As a result of these findings, arson, homicide, and animal death investigations were opened. As part of the animal death investigation, all of the cats were submitted for veterinary forensic autopsies. All cats had soot on the fur and had soot deposits within the oral cavity, esophagus, and respiratory tract. Two cats had soot within the stomach. Cardiac blood was analyzed for carboxyhemoglobin using a CO-oximeter, and all cats had levels >65%. The cause of death was determined to be due to toxic smoke inhalation from the structure fire. Case findings support the potential use of CO-oximeter for determination of carboxyhemoglobin levels in cats and continued research in this area of forensic practice.

How to Decide Oxygen Therapy in Childhood Carbon Monoxide Poisoning?

Carbon monoxide poisoning is an important cause of morbidity and mortality all over the world. In our study, it was aimed to determine the clinical and laboratory parameters that may be effective in deciding the need for hyperbaric oxygen therapy in the management of cases. From January 2012 to the end of December 2019, 83 patients who applied to a university hospital pediatric emergency department in İstanbul with the diagnosis of carbon monoxide poisoning were included. Demographic characteristics, carbon monoxide source, exposure duration, treatment approach, physical examination findings, Glasgow Coma Score, laboratory results, electrocardiogram, cranial imaging, and chest x-ray were evaluated from the records. The median age of the patients was 56 (37.0-100.0) months and 48 (57.8%) of them were male. The median time of exposure to carbon monoxide was 5.0 (0.5-3.0) hours in those who received hyperbaric oxygen therapy and was significantly higher than those who received normobaric oxygen therapy (P < .001). Myocardial ischemia, chest pain, pulmonary edema, and renal failure were not detected in any of the cases. The median lactate level was detected as 1.5 (1.0-2.15) mmol/L in those who received normobaric oxygen therapy and 3.7 (3.17-4.62) mmol/L in those who received hyperbaric oxygen therapy, and the difference between them was statistically significant (P < .001). A guideline containing precise clinical and laboratory parameters for hyperbaric oxygen therapy in children has not been developed yet. In our study, carbon monoxide exposure duration, carboxyhemoglobin levels, neurological symptoms, and lactate levels were found to be guiding parameters in determining the need for hyperbaric oxygen therapy.

Predictive Value of Complete Blood Count, Venous Blood Gas Measurements, and Glucose/Potassium Ratio for Delayed Neuropsychiatric Syndrome in Children with Acute Carbon Monoxide Poisoning Due to Coal-Burning Stove.

Delayed neuropsychiatric syndrome may occur after carbon monoxide poisoning has completely healed. The literature on indicators to predict delayed neuropsychiatric syndrome in pediatric patients is limited. The aim of the study is to investigate the effectiveness of complete blood count parameters, neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, systemic immune inflammation index, glucose/potassium ratio, venous blood gas parameters, and carboxyhemoglobin in predicting delayed neuropsychiatric syndrome in children with carbon monoxide poisoning due to coal-burning stove. The patients admitted to the pediatric emergency department with acute carbon monoxide poisoning between 2014 and 2019 were analyzed. The patients were divided into 2 groups as delayed neuropsychiatric syndrome (+) and delayed neuropsychiatric syndrome (-). Neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, systemic immune inflammation index (platelet count×neutrophil count/lymphocyte count), and glucose/ potassium ratio were calculated. Of the 137 patients, 46 were diagnosed with delayed neuropsychiatric syndrome within 1 year of carbon monoxide poisoning. A control group was formed from 137 age- and sexmatched children. Glasgow Coma Scale < 15 was found in 11% of patients with delayed neuropsychiatric syndrome (-) and 8.7% of patients with delayed neuropsychiatric syndrome (+) (P = .773). Blood glucose, potassium, glucose/potassium ratio, platelet/lymphocyte ratio, white blood cell, neutrophil count, lymphocyte count, neutrophil/lymphocyte ratio, systemic immune inflammation index, venous partial pressure of carbon dioxide, carboxyhemoglobin, and methemoglobinemia levels were significantly different between control, delayed neuropsychiatric syndrome (+), and delayed neuropsychiatric syndrome (-) groups (P < .05). The most effective predictors for delayed neuropsychiatric syndrome were systemic immune inflammation index (area under the curve = 0.852; cut-off value > 1120; sensitivity = 89.1%; specificity = 75.8%), neutrophil (area under the curve = 0.841; cut-off value > 8000/mm3; sensitivity = 78.2%; specificity = 79.1%), and neutrophil/lymphocyte ratio (area under the curve = 0.828; cut-off value > 4; sensitivity = 78.2%; specificity = 75.5%). About one-third of children with carbon monoxide poisoning due to coal-burning stove develop delayed neuropsychiatric syndrome. Systemic immune inflammation index, neutrophil count, and neutrophil/lymphocyte ratio obtained immediately after the poisoning in the pediatric emergency department may be effective predictors for delayed neuropsychiatric syndrome.

Evaluation of Plasma Total Thiol Levels in Patients with Carbon Monoxide Poisoning in the Emergency Department

Objective: The study aimed to measure the levels of total thiol, an antioxidant parameter, in patients who presented to the emergency department (ED) with carbon monoxide (CO) poisoning under normobaric oxygen therapy (NBOT), evaluate the time-dependent changes in total thiol levels within the first 6 hours, and examine the course of antioxidants in CO poisoning. &#x0D; Materials and Method: The study population consisted of 85 patients diagnosed with CO poisoning in the ED and 50 volunteers. Total thiol level was measured in the study group at the admission (T0), first (T1) and sixth hour (T6). Carboxyhemoglobin levels, cardiac markers, electrocardiography, and routinely requested tests were investigated in patients with poisoning. The total thiol level was measured in the volunteer group. &#x0D; Results: There was a significant decrease in total thiol mean levels between T0 and T1 (p

Race, hypoxaemia and oxidative stress in prematurely-born infants

BackgroundDisparities in neonatal respiratory outcomes in prematurely-born infants might be partially explained by racial differences and the relationship of hypoxia and oxidative stress. AimsTo determine if Black, preterm infants were exposed more frequently to hypoxaemia compared to White infants and had a higher level of oxidative damage. Study designSingle-centre retrospective cohort study at King's College Hospital, London, UK between 2018 and 2021. SubjectsInfants born before 32 completed weeks of gestational age. Outcome measuresThe median arterial oxygen saturation (SaO2) over the first seven days was measured. The maximum carboxyhaemoglobin (COHb) level for the first three days was also recorded as an index of oxidative stress. ResultsTwo thousand and sixty blood gases from 87 infants (38 Black) with a median (IQR) gestational age of 26.4 (24.6–28.3) weeks were analysed. The median (IQR) SaO2 was not significantly different in Black [96.1 (95.2–96.8) %] compared to White infants [96.7 (95.6–97.7) %, p = 0.24]. The median (IQR) COHb was not significantly different in Black infants [1.9 (1.7–2.4) %] compared to White infants [1.9 (1.7–2.3) %, p = 0.77]. The highest COHb was significantly related to the median SaO2 in all infants (r = −0.51, p < 0.001) and separately in Black (r = −0.50, p = 0.002) and White (r = −0.56, p < 0.001) infants. ConclusionsPreterm, Black infants were not exposed more frequently to hypoxaemia compared to White infants. Lower saturation levels were associated with higher maximum carboxyhaemoglobin levels indicating a higher risk of oxidative stress, irrespective of racial background.

Comparison of Carboxyhemoglobin (COHb) Levels in the Blood of Active and Passive Smokers in Bulupitu Bus Terminal Workers, Banyumas Regency

Carbon monoxide (CO) is a colorless, tasteless, and odorless gas, but in high concentrations in the blood, it can cause death. One of the CO2 can come from cigarette smoke. When cigarette smoke is inhaled, the affinity of CO with the blood is stronger than for oxygen, and this will increase the carboxyhemoglobin (HbCO) in the blood. Passive smokers who are often near active smokers will inhale cigarette smoke. This study aims to compare HbCO levels in the blood between active and passive smokers of Bulupitu terminal workers, Banyumas Regency. This was an analytical observational study with six active and six passive smokers who are terminal workers. All active and passive smokers samples had HbCO concentrations above the normal HbCO threshold of 3.5%. The measurement results showed the average HbCO level of smokers was 5.87%. Determining differences in HbCO levels in the blood of active and passive smokers was conducted using the Independent Test (p-value = 0.370). This value shows no significant difference in blood HbCO levels in active and passive smokers.

Argyrophilic nucleolar organizer regions as a promising biomarker for the detection of brain hypoxia levels caused by different doses of carbon monoxide poisoning.

The purpose of the study is to investigate whether there is any relationship between mean argyrophilic nucleolar organizing regions (AgNOR) number and total AgNOR area/total nuclear area (TAA/TNA) ratio and the levels of brain hypoxia after exposure to different acute doses of carbon monoxide (CO) gas. Each experimental group was exposed to CO gas (concentrations of 1,000, 3,000 and 5,000 ppm). Then, the rats were anesthetized, and blood samples were taken from the right jugular vein for carboxyhemoglobin levels detection. The rats were sacrificed on seventh day. AgNOR staining was applied to brain tissues. TAA/TNA and mean AgNOR number were detected for each nucleus. Significant differences were detected among all groups for TAA/TNA ratio, mean AgNOR number and carboxyhemoglobin level. According to a double comparison of groups, the differences between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 5,000 ppm were significant for TAA/TNA ratio. When mean AgNOR number was considered, significant differences were detected between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 3,000 ppm. AgNOR proteins may be used for early detection of the duration, intensity, and damage of brain injury caused by CO poisoning. Thus, effective treatment strategies can be developed for the prevention of hypoxic conditions.

Clinical and Laboratory Characteristics Predicting the Severity of Carbon Monoxide Poisoning in Children: A Single-Center Retrospective Study.

Carbon monoxide poisoning (COP) is extremely common throughout the world. The purpose of this study was to assess the demographic, clinical, and laboratory characteristics predicting the severity COP in children. The study included 380 children diagnosed with COP between January 2017 and January 2021 and 380 healthy controls. Carbon monoxide poisoning was diagnosed based on the medical history and a carboxyhemoglobin (COHb) level of more than 5%. The patients were classified as mild (COHb 10%), moderate (COHb 10%-25%), or severely (COHb > 25%) poisoned. The mean age of the severe group was 8.60 ± 6.30, for the moderate group was 9.50 ± 5.81, for the mild group was 8.79 ± 5.94, and for the control group was 8.95 ± 5.98. The most common place of exposure was at home and all cases were affected accidentally. The coal stove was the most common source of exposure, followed by natural gas. The most common symptoms were nausea/vomiting, vertigo, and headache. Neurologic symptoms such as syncope, confusion, dyspnea, and seizures were more common in the severe group. A total of 91.3% of the children had hyperbaric oxygen therapy, 3.8% were intubated, and 3.8% were transferred to intensive care in the severe group, whereas no death or sequela was observed. Mean platelet volume and red cell distribution width had the highest area under the curve in the receiver operating characteristic analysis (0.659; 0.379). A positive and low statistically significant relationship was found between COHb levels and troponin and lactate levels in the severe group ( P < 0.05). Carbon monoxide poisoning progressed more severely in children presented with neurological symptoms and have elevated red cell distribution width and mean platelet volume. Even in severe COP cases, satisfactory results have been obtained with early and appropriate treatment.

First-day computed tomography: does it has a role in the assessment of patients with inhalation lung injury?

BackgroundInhalation lung injury occurs in almost one-third of all serious burns and is responsible for a considerable proportion of burn patient fatalities each year. History of closed space fire or unconsciousness at the accident site, occurrence of pharyngeal or facial burns, hoarseness, and wheezing, and laboratory tests that include blood gas abnormalities or Carboxyhemoglobin levels in blood ˃ 10% are used to diagnose inhalation lung injury. It is also characterized by radiological findings of alveolar or interstitial edema, atelectasis, and/or consolidations, as well as the presence of erythema with laryngeal or tracheal edema in the bronchoscope.ObjectivesTo study the diagnostic and prognostic efficacy of radiologist score and bronchial wall thickening as radiological CT findings in inhalation lung injury.MethodsThis prospective case–control study included 48 patients with inhalation lung injury (ILI) as a case group and 10 patients without ILI were selected as the control group, all recruited from the burn and plastic department. Within the first 12 h of suspected ILI, a fiberoptic bronchoscope was done to confirm the diagnosis. An initial chest X-ray was done followed by computed tomography through which the radiologist score (RADS) together with bronchial wall thickening (BWT) was done.ResultsDuration of ventilation was higher in cases than in controls (8.50 ± 3.94 vs 3.25 ± 0.50). The hospital duration was higher in cases than in controls (13.6 ± 4.68 vs9.50 ± 4.52). The BWT was 2.12 ± 0.66 (mean ± SD) in the ILI group while the control group was 1.32 ± 0.48 (mean ± SD). Correlating between baseline PaO2 and RADS score and BWT, it was found that there was a highly significant negative correlation between PaO2 and RADS score and BWT among inhalation lung injury patients (P value 0.001). The sensitivity of BWT in the detection of the need for mechanical ventilation was 83% at a cut-off point of 1.65. Its specificity was 78% and accuracy 75%.ConclusionCT done within 24 h of burn patients has a good role in the diagnosis and management of ILI from the burn.

AN OVERVIEW OF CARBON MONOXIDE DEATHS IN KUWAIT BETWEEN YEARS 2013-2019 WITH FOUR RARE CASES PRESENTATION: A FORENSIC PRACTITIONER EXPERIENCE.

Background: Carbon monoxide (CO) is an odorless, colorless, non-irritating highly toxic gas produced after the incomplete combustion of hydrocarbons. CO forms carboxyhaemoglobin (COHb), which will lead to severe tissue hypoxia and death in some cases. Materials and Method: In the present study, we will discuss the commonest causes of deaths due to CO toxicity in Kuwait between the years 2013-2019 from the perspective of a forensic medicine practitioner in the Forensic Medicine Department in the General Administration for Criminal Evidence – Ministry of Interior- Kuwait. Additionally, we present a rare accidental death of four cases (2 male and female partners), which were handled in 2015 and 2016 in the Forensic Medicine Department. Each couple was found dead in a car parked in an open space and the lethal levels of COHb were detected in their bloods. Result and conclusion: Between the years 2013-2019, in every 100 cases of non-criminal deaths that occur yearly in Kuwait, there were 1-3 cases of CO accidental poisoning (1-2%). The ages ranged from 9 months until 81 years. The range of the COHb concentration in the blood sample was from 36.5% to 80%. The most common cause was smoke inhalation in fires (60%). Defective coal stove was less common which is believed to occur only during winter months (20%). Consequently, the presentation of four autopsies of cases found dead in closed cars in open spaces, after accidental lethal CO inhalation, was worth mentioning. After expert examination, both cars showed defective engines where the CO level increases inside the cabinet which led to death while the cars were in an open land. These cases are worthwhile reporting being rarely described in forensic toxicology.

Carboxyhemoglobin Levels in Preterm Neonatal Late-Onset Sepsis: to Predict or not to Predict.

In this study, we aimed to evaluate carboxyhemoglobin (COHb) levels in diagnosing late-onset sepsis (LOS) in preterm neonates. The records of culture-positive LOS in preterm neonates hospitalized in NICU from January 2017 to July 2022 were reviewed. COHb levels, C-reactive protein, procalcitonin, and neutrophil to lymphocyte ratio of septic preterm infants were compared to controls. In addition, serial COHb levels measured within six hours before or 24h after blood culture sampling, three to seven days prior, and three to five days after starting antimicrobial therapy were retrieved from patient records. The study included 77 blood-culture-positive preterm infants and 77 non-septic controls. During the LOS episode, the COHb values were found to be significantly increased (median: 1.8, IQR: 1.4-2.5) when compared to the control group (median: 1.2, IQR: 0.8-1.6) (p < 0.001). ROC analysis yielded an AUC of 0.714 for COHb (95% CI: 0.631-0.796, p<0.001). At an optimal cut-off of >1.5%, the test's sensitivity was 64.94%, the specificity was 72.73%, the positive predictive value was 70.42%, and the negative predictive value was 67.47%. LOS led to a dramatic rise followed by a decrease after the initiation of the antimicrobial therapy [1.8 (1.4-2.5)] vs. [1.45 (0.2-4)] p<0.001. COHb levels increased at the beginning of LOS, decreasing in response to antibiotics. When used in conjunction with other sepsis biomarkers, the variation of COHb can be important in evaluating late-onset sepsis episodes in preterm infants.

Burn index, burn characteristics and carboxyhemoglobin levels in indoor fire-related deaths: Significance and interpretation of the autopsy findings

IntroductionThe Burn Index (BI) is a significant clinical prognostic parameter for patients with burns. It simultaneously considers major mortality risk factors: age and burns extensivity. Despite the inability to distinguish between ante- and post-mortem burns, their characteristics on autopsy might indicate if a significant thermal injury occurred before the onset of death. We investigated whether autopsy BI, burn extensivity, and severity could tell whether burns were the concurrent cause of fire-related death (FRD), even if the body remained in a fire. Material and methodsTen-year retrospective study analyzed FRD that occurred at the scene in a confined space. Soot aspiration was the main inclusion criterion. Autopsy reports were reviewed for demographic data, burn characteristics (degree, Total Body Surface Area burned- TBSA), coronary artery disease, and blood ethanol. We calculated the BI as a sum of the victim's age and percentage of TBSA affected by 2nd, 3rd and 4th-degree burns. Cases were divided into two groups: those with COHb≤ 30% and with COHb> 30%. Subjects with burned TBSA≤ 40% were analyzed separately afterward. ResultsThe study included 53 males (71.6%) and 21 females (28.4%). No significant difference in age was observed between groups (p > 0.05). COHb≤ 30% had 33, and COHb> 30% had 41 victims. BI and burns extensivity (TBSA) had significant negative correlation with COHb values (ρ = −0.581, p < 0.01 and ρ = −0.439, p < 0.01, respectively). Both were significantly higher in subjects with COHb≤ 30% compared to those with COHb> 30% (140.7 ± 29.57 vs. 95.49 ± 38.49, p < 0.01 and 98 (13−100) vs. 30 (0−100), p < 0.01, BI and TBSA respectively). BI had excellent and TBSA fair performance for detection of subjects with COHb≤ 30% on ROC curve analysis (AUCs 0.821, p < 0.001 and 0.765, p < 0.001), with optimal cut-off values: BI≥ 107 (sensitivity 81.3%, specificity 70.7%) and TBSA≥ 45 (sensitivity 84.8%, specificity 70.7%). On logistic regression analysis BI≥ 107 was independently associated with COHb≤ 30% values (aOR 6; 95%CI 1.55–23.37). The same holds for the presence of 3rd-degree burns (aOR 5.9; 95%CI 1.45–23.99). In the subgroup of subjects with TBSA≤ 40% burned, those with COHb≤ 50% were significantly older than victims with COHb> 50% (p < 0.05). Here BI≥ 85 was a particularly good predictor for detection of subjects with COHb≤ 50% (AUC=0.913, p < 0.001, 95% CI 0.813–1.00; sensitivity 90.9%, specificity 81%). ConclusionThe BI≥ 107, TBSA≥ 45% burned, and 3rd-degree burns observed on autopsy point to a significantly higher odds that limited CO intoxication occurred, and burns should be considered a concurrent cause of indoor FRD. When less than 40% of TBSA was affected, BI≥ 85 indicated sub-lethal CO poisoning.

Screening patients for unintentional carbon monoxide exposure in the Emergency Department: a cross-sectional multi-centre study.

Low-level exposure to carbon monoxide (CO) is a significant health concern but is difficult to diagnose. This main study aim was to establish the prevalence of low-level CO poisoning in Emergency Department (ED) patients. A prospective cross-sectional study of patients with symptoms of CO exposure was conducted in four UK EDs between December 2018 and March 2020. Data on symptoms, a CO screening tool and carboxyhaemoglobin were collected. An investigation of participants' homes was undertaken to identify sources of CO exposure. Based on an ED assessment of 4175 participants, the prevalence of suspected CO exposure was 0.62% (95% CI; 0.41-0.91%). CO testing in homes confirmed 1 case of CO presence and 21 probable cases. Normal levels of carboxyhaemoglobin were found in 19 cases of probable exposure and in the confirmed case. This study provides evidence that ED patients with symptoms suggestive of CO poisoning but no history of CO exposure are at risk from CO poisoning. The findings suggest components of the CO screening tool may be an indicator of CO exposure over and above elevated COHb. Clinicians should have a high index of suspicion for CO exposure so that this important diagnosis is not missed.

Diagnosis and Clinical Significance of «Hidden» Spectral Disorders of Blood Oxygenation Among Smokers with Exacerbation of Bronchial Asthma

The purpose of the study — to identify and evaluate the clinical significance of “hidden” disorders of blood oxygenation in smokers with exacerbation of bronchial asthma.Materials and methods: spirometry, pulse oximetry, CO-metry of exhaled air. To diagnose “hidden” disorders of blood oxygenation, including “hidden” violations of the spectral characteristics of the level of hemoglobin oxygen saturation, 19 male smokers (middle age 54,6±2,05 years) with exacerbation of mixed (68 %) or allergic (32 %) bronchial asthma were examined.The results: the accuracy of the clinical assessment of blood oxygenation in smokers increased significantly after the correction of the SpO2 level to the level of carboxyhemoglobin with the help of a computer program developed by us, which made it possible to diagnose a clinically significant lifethreatening exacerbation of this disease in smoking patients with bronchial asthma, since “hidden” respiratory insufficiency was detected in a timely manner.

Impact of smoking on oral cavity by comparing carbon monoxide and carboxyhemoglobin levels with salivary pH in smokers of Salem district

Objective: Saliva is the first biological fluid exposed to the smoke and other contents of the cigar, which can cause structural and functional changes in saliva. Salivary pH is an important biomarker for detecting oral diseases. Cigarette smoke contains many toxic gases, of which, carbon monoxide (CO), plays a deleterious role in causing systemic illness in a person. As a result, a measure of exhaled CO (eCO), similar to exhaled Nitric Oxide, has been evaluated as a potential breath biomarker to detect smoking status and validate smoking cessation to prevent other systemic defects caused by smoking. The present study would investigate the effect of CO and carboxyhemoglobin (HbCO%) on the pH of the oral cavity of individuals with smoked tobacco habit. Materials and Methods: For this study, 60 male patients aged 18–55 years with smoking habit of a minimum of two cigarettes or beedis per day for a minimum period of one year reporting to the Department of Oral Medicine and Radiology were divided based on their smoking habit and type of smoked tobacco into two groups with each group consisting of 30 participants. To determine the eCO levels and HbCO% levels, a breath analyzer (piCOTM Smokerlyzer®) was used. Patients were asked to hold their breath for 15 s, place their lips tightly around the mouthpiece of the breath analyzer, and gently exhale through the mouthpiece as long as possible. CO levels in exhaled breath (eCO) in parts per million and HbCO% in the percentage of red blood cells carrying CO (HbCO%) were displayed on the display monitor. A digital pH meter was used to calculate the salivary pH from unstimulated saliva samples. The salivary pH readings, along with the eCO and HbCO%, were recorded in the tabular column for each patient. Results: In the present study, the cigarette smokers had a higher mean value of eCO levels. Similarly, cigarette smokers had higher mean HbCo% levels than beedi smokers. It was also observed that salivary pH of smokers was found to be altered when compared to non-smokers. Conclusion: The current study found that the level of CO in exhaled breath correlates with the HbCO% present in the blood, alerting tobacco users to the hidden fatality and therefore serving as an indicator in tobacco cessation programs to raise awareness of the effects of smoking on oral health. Furthermore, along with CO levels the pH of saliva was altered, demonstrating the dangers of tobacco and its products.