Carboxyhemoglobin Research Articles

Semiquantitative screening of trace combustion-derived volatile substances in the blood of fire victims using NeedlEx® headspace gas chromatography/mass spectrometry

BackgroundVarious autopsy findings are used for the diagnosis of burning death, including inhalation injury, soot in the respiratory tract, vital reaction, blood carboxyhemoglobin (COHb), and blood cyanide. However, not all findings are necessarily complete, and autopsy diagnosis can be difficult in cases where there are few findings. In this study, we analyzed combustion-derived volatile substances (CVSs) in post-mortem blood in fire-related cases, focusing on those that occur when buildings and furniture thermally decompose during a fire, and evaluated these as potential new autopsy findings. MethodsThe blood CVSs of 61 fire-related cases from 2013 to 2015 were analyzed by a rapid and operationally simple method that employed a gas chromatograph–mass spectrometer coupled to a NeedlEx®, an extraction needle packed with a medium that selectively adsorbs volatile organic compounds. ResultsA total of 39 types of aliphatic and aromatic hydrocarbons were detected in the blood of fire victims. They could be detected even in post-mortem blood with COHb <10%, cyanide concentration <0.25μg/ml, and no soot in the respiratory tract. Styrene was detected in all cases except for one case of burning suicide with kerosene. The blood CVSs could be readily differentiated between the victims of building fires, self-immolation with kerosene, and self-immolation with gasoline: the presence of alpha-methylstyrene with a large amount styrene indicated a building fire; the detection of C9–C12 aliphatic hydrocarbons and C3 alkylbenzenes suggested a kerosene-related fire; and the detection of large amount of toluene and C3 alkylbenzenes indicated a gasoline-related fire. The number of blood CVSs detected for the building fire victims showed correlations with COHb level, cyanide concentration, and the amount of soot. With self-immolation, the number of blood CVSs detected showed weak correlation with COHb level, cyanide concentration, or amount of soot. ConclusionAnalysis of blood CVSs enabled the identification of the type of fire-related death, which is impossible by conventional autopsy findings.

Pulmonary Phototherapy to Treat Carbon Monoxide Poisoning in Rats.

Carbon monoxide (CO) poisoning is a common cause of poison-related mortality. CO binds to hemoglobin in the blood to form carboxyhemoglobin (COHb), impairing oxygen delivery to peripheral tissues. Current treatment of CO-poisoned patients involves oxygen administration to rapidly remove CO and restore oxygen delivery. Light dissociates CO from COHb with high efficiency. Exposure of murine lungs to visible laser-generated light improved the CO elimination rate in vivo. The aims of this study were to apply pulmonary phototherapy to a larger animal model of CO poisoning, to test novel approaches to light delivery, and to examine the effect of chemiluminescence-generated light on the CO elimination rate. Anesthetized and mechanically ventilated rats were poisoned with CO and subsequently treated with air or oxygen combined with or without pulmonary phototherapy delivered directly to the lungs of animals at thoracotomy, via intrapleural optical fibers or generated by a chemiluminescent reaction. Direct pulmonary phototherapy dissociated CO from COHb reducing COHb half-life by 38%. Early treatment with phototherapy in critically CO poisoned rats improved lactate clearance. Light delivered to the lungs of rats via intrapleural optical fibers increased the rate of CO elimination without requiring a thoracotomy, as demonstrated by a 16% reduction in COHb half-life. Light generated in the pleural spaces by a chemiluminescent reaction increased the rate of CO elimination in rats breathing oxygen, reducing the COHb half-life by 12%. Successful application of pulmonary phototherapy in larger animals and humans may represent a significant advance in the treatment of CO-poisoned patients.

Carbon Monoxide Poisoning in the Veterans Health Administration, 2010 - 2016

ObjectiveTo describe characteristics of Veterans Health Administration(VHA) patients with ICD 9/10 CM inpatient discharge and/oremergency department (ED)/urgent care outpatient encounter codesfor carbon monoxide (CO) poisoning.IntroductionIt is estimated that in the United States (US), unintentional non-firerelated CO poisoning causes an average of 439 deaths annually, and in2007 confirmed CO poisoning cases resulted in 21,304 ED visits and2,302 hospitalizations (71 per million and 8 per million population,respectively)1. Despite the significant risk of morbidity and mortalityassociated with CO poisoning, existing surveillance systems in theUnited States are limited. This study is the first to focus specificallyon CO poisoning trends within the VHA population.MethodsQueries were performed in VA PraedicoTMPublic HealthSurveillance System for inpatient discharges and emergency roomand urgent care outpatient visits with ICD 9/10 CM codes for COpoisoning from 1/1/2010 – 6/30/2016. A dataset of unique patientencounters with CO poisoning was compiled and further classified asaccidental, self-harm or unspecified. Patients with carboxyhemoglobin(COHb) blood level measurements≥10%2for the same timeframewere extracted and merged with the CO poisoning dataset.We analyzed for demographic, geographic and seasonal variables.Rates were calculated using total unique users of VHA care formatching time frame and geographic area as denominators.ResultsThere were a total of 671 unique VHA patients identified with COpoisoning. Of these, 298 (44%) were classified as accidental, 104(15%) self-harm, and 269 (40%) unspecified. A total of 6 patientsdied within 30 days of their coded diagnosis, however only 1 ofthese was directly attributable to CO poisoning. The overall rate ofCO poisoning over the study time frame was 18 per million uniqueusers of VHA care. CO poisoning diagnoses were obtained from396 (59%) outpatients, 216 (32%) inpatients, and 59 (9%) patientswith both and outpatient visit and inpatient admission. Patientswith self-harm classification were less likely to be seen in the ED(only 24 (6%) unique patients compared to 190 (48%) accidental and182 (46%) unspecified classifications). Of patients seen in the ED andsubsequently admitted, patients with the classification of accidentalpoisoning made up the largest percentage with 36 unique patients(61%). There were 71 (11%) females compared to 600 (89%) males.The highest represented age group was 45-64 with 342 unique patients(51%). Rates by US Census Region were highest in the Midwestand Northeast (27 and 23 per million unique users, respectively)compared to the West and South (15 and 13 per million uniqueusers, respectively) (Figure 1). Accidental CO poisonings showed aseasonal pattern with peaks occurring in late fall, winter, and earlyspring months (Figure 2). CO poisonings classified as unspecifiedhad a similar but less pronounced pattern, while those classified asself-harm were too few to observe any pattern over time. COHb bloodlevels≥10% were present in 111 (17%) of patients with CO poisoningcodes. Of patients with COHb measures≥10%, those with self-harmclassification were least represented with only 7 unique patients (6%).Accidental and unspecified classifications were equally representedwith 53 (48%) and 51 (46%) unique patients, respectively.ConclusionsThe impact of CO poisoning on the VHA patient population hasnot been well studied. The geographic distribution of the majorityof cases in the Midwest and Northeast, and the seasonal distributionof accidental cases in colder months seems to be appropriate withrespect to what is known of unintentional CO poisoning as oftenassociated with heat-generating sources3. Opportunities for furtherinvestigation include how potential CO poisoning cases are evaluatedin VHA given the low percentage of cases with COHb blood levelmeasurements.

Pharmacologically increasing collateral perfusion during acute stroke using a carboxyhemoglobin gas transfer agent (Sanguinate™) in spontaneously hypertensive rats

Similar to patients with chronic hypertension, spontaneously hypertensive rats (SHR) develop fast core progression during middle cerebral artery occlusion (MCAO) resulting in large final infarct volumes. We investigated the effect of Sanguinate™ (SG), a PEGylated carboxyhemoglobin (COHb) gas transfer agent, on changes in collateral and reperfusion cerebral blood flow and brain injury in SHR during 2 h of MCAO. SG (8 mL/kg) or vehicle (n = 6–8/group) was infused i.v. after 30 or 90 min of ischemia with 2 h reperfusion. Multi-site laser Doppler probes simultaneously measured changes in core MCA and collateral flow during ischemia and reperfusion using a validated method. Brain injury was measured using TTC. Animals were anesthetized with choral hydrate. Collateral flow changed little in vehicle-treated SHR during ischemia (−8 ± 9% vs. prior to infusion) whereas flow increased in SG-treated animals (29 ± 10%; p < 0.05). In addition, SG improved reperfusion regardless of time of treatment; however, brain injury was smaller only with early treatment in SHR vs. vehicle (28.8 ± 3.2% vs. 18.8 ± 2.3%; p < 0.05). Limited collateral flow in SHR during MCAO is consistent with small penumbra and large infarction. The ability to increase collateral flow in SHR with SG suggests that this compound may be useful as an adjunct to endovascular therapy and extend the time window for treatment.

Carbon monoxide-related fatalities: A 60-year single institution experience

ObjectiveThough carbon monoxide (CO) poisonings account currently for a relatively small percentage of total non-natural deaths in Europe, they represent a serious public health burden and significant component of avoidable mortality in many countries. Our aim was to investigate long-term trends and to determine epidemiologic characteristics of the CO-related deaths in the Czech Republic, recorded at the Department of Forensic Medicine in Hradec Králové. MethodsThis was an autopsy-based single-centre retrospective cohort study of all fatalities caused by CO poisoning over six decades (1947–2006). All data were numerically evaluated and processed using NCSS 10 Statistical Software. Statistical significance was defined as a p-value less than 0.05. ResultsA total of 1233 CO-related deaths were identified for inclusion in the study. The manner of death was ranked in order as follows: 45% accidental poisoning, 40% suicidal poisoning, 1% homicidal poisoning, 14% remained undetermined. There were slightly more male victims (59%) than female, and the mean age overall was 48 years. The majority of CO-related fatalities were attributed to coal gas inhalation, with the remainder being from inhaled motor vehicle exhaust fumes, inhaled fire smoke, and other combustion sources such as charcoal, gas and wood-burning appliances. The mean blood carboxyhemoglobin (COHb) level was 66%. A positive blood ethanol concentration was measured in 455 (37%) cases examined. Non-intentional poisonings were highly correlated with the winter months. ConclusionThis study shows that the prevalence of CO-related deaths has decreased significantly in the Czech Republic following the widespread detoxification of the domestic gas in the 1990–1995. Our findings suggest that acute ethanol use, poorer socioeconomic position, and inadequate education status about the danger of CO are associated with an increased risk of fatal CO poisoning. Finally, our results demonstrate the continued value of the autopsy in monitoring global public health security issues and socioeconomic situation. Further similar large-scale studies in different populations are needed to improve the targeting of interventions to the groups with the highest level of risk, and to understand the sources of variation in CO-related mortality.

Correlation between clinical severity and different non-invasive measurements of carbon monoxide concentration: A population study.

ObjectivesCarbon monoxide (CO) poisoning is a major concern in industrialized countries. Each year, thousands of victims, resulting in approximately 100 fatalities, are encountered in France. The diagnosis of CO poisoning is challenging; while carboxyhemoglobin (COHb) may be useful, it is a weak indicator of the severity of CO poisoning. This weak indicator may be a result of the delay between poisoning occurrence and the blood assay. Two apparatuses, CO oximeters and exhaled CO analyzers, now permit COHb to be determined outside hospitals. Our hypothesis is that these instruments allow the early measurement of COHb concentrations, which are more correlated with the severity of poisoning, expressed using the poisoning severity score (PSS).DesignIn an observational and retrospective cohort study, the distribution of COHb measurements obtained by CO oximetry or by exhaled CO analyzers was compared between groups of severity expressed using the PSS.SettingData were collected in the Paris area from January 2006 to December 2010 by the French Surveillance System of CO poisoning.ParticipantsAll patients with CO poisoning reported to the French Surveillance System of CO poisoning.ResultsThere was a significant difference in the COHb values obtained by CO oximetry between groups stratified according to PSS (p<0.0001). A significant difference in the values of exhaled CO was also observed between PSS groups (p = 0.006), although the relationship was not linear.ConclusionsThe COHb concentrations measured using CO oximetry, but not those measured using exhaled CO analyzers, were well correlated with the severity of CO poisoning.

Carbon monoxide reduces near-infrared spectroscopy determined ‘total’ hemoglobin: a human volunteer study

Carbon monoxide (CO) increases middle cerebral artery mean flow velocity (MCAVmean), but the effect of CO on the near-infrared spectroscopy (NIRS) determined cerebral oxygenation (ScO2) is not detailed. In our study, 11 non-smoking subjects breathed 100% O2 through a closed circuit. A CO2 scrubber with CO (1.5 mL kg−1) was added to the circuit. Two NIRS systems (NIRO-200NX and INVOS-5100) assessed ScO2 as the ratio of oxygenated to deoxygenated hemoglobin, while venous blood samples were analyzed for carboxyhemoglobin (COHb). After CO/O2 rebreathing COHb increased to 8.7% (IQR; 7.9–9.4; p = .004) vs. normoxia, but MCAVmean remained stable (55.6 cm s−1; 53.1–69.7) compared to inhalation of O2 (54.6 cm s−1; 48.4–62.9; p = .178) and normoxia (54.1 cm s−1; 44.5–66.9; p = .055). Also, INVOS-5100 determined ScO2 increased during CO/O2 (74.4 ± 7.5%) and O2 inhalation (73.1 ± 7.2%) compared to normoxia (68.9 ± 6.9%; p < .001). In contrast, NIRO-200NX determined ScO2 remained unchanged during CO/O2 and O2 inhalations but oxygenated and deoxygenated hemoglobin decreased (by 19.7 μM (median; IQR 2.8–34.8; p = .016) and 37.3 μM (30.8–46.6; p = .004), respectively) during inhalation of CO/O2 compared to inhalation of O2. Therefore, NIRO-200NX determined ‘total’ hemoglobin (sum of O2Hb and HHb) decreased (by 62.1 μM; 44.5–78.2; p = .001). In conclusion, exposure to CO did not increase MCAVmean, and neither NIRO-200NX nor INVOS-5100 detected a change in ScO2 when CO was added to inhalation of oxygen. Unaffected ScO2 after exposure to CO reflected a similar decrease in oxygenated and deoxygenated hemoglobin suggesting that detection of exposure to CO by NIRS should focus on ‘total’ hemoglobin rather than on ScO2.

Manner of Death Determination in Fire Fatalities: 5-Year Autopsy Data of Istanbul City.

Death resulting from burns is an important social problem and a frequent accident. However, because approximately 10% of cases are estimated to result from a fire that was deliberately started, all fire-related deaths should be treated as suspicious, and the cause of a fire should be investigated. For the bodies recovered from the scene of a fire, the manner of death could also be suicide or homicide. The objective of this study was to contribute to the clarification of controversial data present in the literature on the manner of death determination of fire-related deaths, through evaluation of autopsy findings of bodies recovered from fires. We reviewed 20,135 autopsies performed in a 5-year period, in Istanbul, as the whole autopsy data of the city and found 133 fire-related deaths. The death scene investigation reports and other judicial documents, autopsy findings, and toxicological analysis results were evaluated to determine the parameters of age, sex, level of the burn, vital signs [red flare; soot in the lower respiratory tract, esophagus, and/or stomach; and screening of carboxyhemoglobin (COHb) levels in the blood], toxicological substances, presence of accelerants, cause of death, and manner of death. The manner of death was determined to be an accident in 98 (73.7%) and homicide in 12 (9%) cases, whereas there was no suicide. In addition, it could not be determined in 23 (17.2%) cases. In accidental deaths, the most frequent cause of death was COHb poisoning with statistically significant blood COHb levels greater than 10%. Further, the presence of soot in the lower respiratory tract, esophagus, and/or stomach and the existence of at least 1 or 2 vital signs together were found to be valid deterministic criteria with statistical significance in terms of identifying the manner of death.

Évolution de la carboxyhémoglobinémie et de la méthémoglobinémie lors de résections endoscopiques : une étude observationnelle

Combustion of organic tissues due to endoscopic resection could induce methemoglobin (MetHb) and carboxyhemoglobin (COHb) formation. The aim of this study is to evaluate MetHb and COHb formation in patients undergoing prostatic or bladder endoscopic procedures. COHb and MetHb measurements were performed in 44patients at the beginning and end of the procedure. A third measurement was done in patients who stayed more than one hour in the recovery room. Means were compared using Student t-test, simple regressions were used for quantitative variables and ANOVA for categorical variables. Multiple linear regressions were used for multivariate analysis. COHb increased by 0.5±0.9% (95% CI: 0.2to 0.7% P=0.001). MetHb increase was 0.0±0.4% (95% CI: -0.1to 0.2% P=0.552). In univariate analysis, the variables associated with COHb increase are the length of surgery, the amount of irrigation fluid and location (prostate or bladder) of the procedure. In the multivariate model, COHb increase is associated with the amount of liquid and the location. MetHb did not increase during endoscopic surgery. In contrast, COHb increases, and can, in some patients, exceed 2-4%. This could be responsible for a decreased angina threshold in patients with ischemic heart disease. 4.

Hyperventilation with Maintenance of Isocapnia. An “Old New” Method in Carbon Monoxide Intoxication

IntroductionExposure to carbon monoxide (CO) is among the most common causes of acute and chronic poisonings worldwide. The crucial point of treatment of such acute poisonings is to eliminate CO from the body as fast as possible. There are currently two approaches to the management of the CO intoxication: hyperbaric oxygen therapy (HOT) and normobaric oxygen therapy (NOT). HOT is highly effective and capable of achieving the CO elimination half-time (T½) as low as 15 minutes. Unfortunately this method is expensive and not always readily available. The elimination of CO with the use of NOT (T½~70 min) is slower, but treatment can be started even on the site of the exposure and continued while the patient is transported to a hospital. The aim of the study was to evaluate the effectiveness of a method using therapeutic hyperventilation with maintenance of isocapnia (IH) in the elimination of CO in volunteers exposed to CO and to compare selected gasometric and respiratory parameters during IH with the values obtained during hyperventilation with pure oxygen (“non-isocapnic hyperventilation”–NIH).Material and methodsThe study involved 13 healthy, chronically-smoking volunteers. Each of them participated in two independent hyperventilation tests: IH and NIH. The levels of carboxyhemoglobin (COHb) and selected gasometric, cardiac and respiratory parameters were measured at 0, 10 and 20 minutes during both tests. Among 13 volunteers (8 women and 5 men) the initial COHb level was 5.0±1.5% (mean±SD) before the IH tests and 5.1±1.9% before the NIH tests (p>0.05). After 20 minutes of the procedures the mean COHb level was 2.9±0.9% for IH and 3.6±1.2% for NIH (p<0.01). The T½ of COHb was 29.6±12.2 min and 47.3±19.2 min respectively (p<0.01). After 10 minutes of NIH respiratory alkalosis was noted in 11 participants (84.6%). Such problem was not seen during the IH procedures. No serious adverse effects were recorded during either IH or NIH. Mild symptoms such as: dyspnea, headache and paresthesias were reported by 6 volunteers (46%) during both IH and NIH tests. It is worth noting that paresthesias were only reported during NIH, by 2 participants (15.4%).ConclusionsThe elimination T½ of CO during IH was comparable with the values reported during HOT, and lower than can be achieved with NOT or NIH. No serious adverse effects were reported during IH procedures. Further studies, especially direct comparisons with NOT and HOT, are necessary to evaluate the effectiveness of IH in the treatment of acute CO poisoning.

Carboxyhemoglobin – the forgotten parameter of neonatal hyperbilirubinemia

Neonatal hyperbilirubinemia is influenced by a wide variety of factors, one of which is hemolysis. Serious hyperbilirubinemia may lead to a kernicterus with detrimental neurologic sequelae. Patients suffering from hemolytic disease have a higher risk of developing kernicterus. Carbon monoxide (CO), a byproduct of hemolysis or heme degradation, was described by Sjöstrand in the 1960s. It is transported as carboxyhemoglobin (COHb) and exhaled through the lungs. We were interested in a potential correlation between COHb and total serum bilirubin (TSB) and the time course of both parameters. We used a point of care (POC) blood gas analyzer and did a retrospective analysis of bilirubin and COHb data collected over a 60-day period. An arbitrary cut-off point set at 2% COHb identified four patients with hemolytic disease of different origins who required phototherapy. In one patient with atypical hemolytic uremic syndrome (aHUS), COHb preceded the rise in bilirubin by about 2 days. Despite this displacement, there was a moderately good correlation of COHb with TSB levels <15 mg/dL (257 μmol/L) (r2: 0.80) and direct bilirubin (r2: 0.78) in the first patient. For all the four patients and all time points the correlation was slightly lower (r2: 0.59). COHb might be useful as a marker for high hemoglobin turnover to allow an earlier identification of newborns at risk to a rapid rise in bilirubin.

Hemodynamic Implications of Carbon Monoxide (CO) and Nitrogen Oxide (NO) during Living Donor Liver Transplantation.

Carbon monoxide (CO) and nitrogen oxide (NO) affect vasodilation and cause hemodynamic change. Hemodynamic instability due to liver transplantation may result in poor prognosis of graft. This study investigated the hemodynamic implications of CO and NO levels measured using carboxyhemoglobin (COHb) and methemoglobin (MetHb) during living donor liver transplantation (LDLT). The hemodynamic instability with a pressor dose (norepinephrine equivalent) was estimated 1 hour after graft reperfusion. COHb and MetHb were used as indexes of CO and NO, and were measured using an arterial blood gas analyzer. One hundred and ten recipients who underwent LDLT from May 2011 to July 2013 were selected. Recipients were divided into high (≥ 1.9%) and low (< 1.9%) COHb groups with COHb concentrations at 5 minutes after reperfusion. Recipients were also divided into high (≥ 0.4%) and low (< 0.4%) MetHb groups with MetHb concentrations at 30 minutes after reperfusion. Data are presented as mean ± standard deviation or number (percentage). Model for End-stage Liver Disease (MELD) scores were different for the two COHb groups (low: 13.4 ± 9.0 vs. high: 19.7 ± 10.6, p < 0.001), and pressor doses adjusted by MELD scores were also different between the two COHb groups (low: 0.09 ± 0.01 μg/kg/min vs. high: 0.14 ± 0.01 μg/kg/min, p = 0.029). By contrast, pressor doses and MELD scores were not different between the two MetHb groups. In conclusion, CO rather than NO has hemodynamic implications during LDLT. Therefore, the increase in COHb during LDLT is predictive of hemodynamic instability.

The Influence of Smoking on the Variations in Carboxyhemoglobin and Methemoglobin During Urologic Surgery.

Introduction:Surgery is supposed to modulate the production of carbon monoxide by the reduction of heme oxygenase activity or transcriptional regulation of inducible heme oxygenase. On the other hand, the inhalation of tobacco smoke can substantially raise the level of carboxyhemoglobin in the blood. Furthermore, methemoglobin is maintained at a constant level. However, excessive production of methemoglobin relative to total methemoglobin reductase activity results in methemoglobin increase.Aim:The aim of our study was to investigate the perioperative variations of carboxyhemoglobin and methemoglobin during urologic surgeries, and at the same time to evaluate the changes in methemoglobin as a possible indicator of nitric oxide generation. Our second aim was to evaluate the effect of preoxygenation on the level of carboxyhemoglobin and methemoglobin and the influence of blood transfusion on their changes.Material and methods:The study included 30 patients scheduled for urologic surgery under general endotracheal anesthesia, aged 18–60 years without any history of respiratory disease, divided into two groups. The study group comprised patients who were smoking cigarettes or tobacco pipe, while the control group included non-smokers. In both groups carboxyhemoglobin (COHb) and methemoglobin (MetHb) levels were determined preoperatively, after preoxygenation, and postoperatively.Results:COHb levels were decreased postoperatively in both groups. The average values of COHb between the two groups were statistically significantly different (p=0.00). MetHb levels increased postoperatively in the group of smokers and decreased in the group of non-smokers. There were no statistically significant differences in the average postoperative MetHb levels between the two groups.Conclusion:Changes in carboxyhemoglobin and methemoglobin concentrations in arterial blood occur during urologic surgery, although these amplitudes are small when compared with carbon monoxide intoxication and methemoglobinemia. It is likely that organ perfusion and functions are affected by these monoxide gas mediators during urologic surgery.

Arterial Carboxyhemoglobin Measurement Is Useful for Evaluating Pulmonary Inflammation in Subjects with Interstitial Lung Disease.

Objective The arterial concentration of carboxyhemoglobin (CO-Hb) in subjects with inflammatory pulmonary disease is higher than that in healthy individuals. We retrospectively analyzed the relationship between the CO-Hb concentration and established markers of disease severity in subjects with interstitial lung disease (ILD). Methods The CO-Hb concentration was measured in subjects with newly diagnosed or untreated ILD and the relationships between the CO-Hb concentration and the serum biomarker levels, lung function, high-resolution CT (HRCT) findings, and the uptake in gallium-67 (67Ga) scintigraphy were evaluated. Results Eighty-one non-smoking subjects were studied (mean age, 67 years). Among these subjects, (A) 17 had stable idiopathic pulmonary fibrosis (IPF), (B) 9 had an acute exacerbation of IPF, (C) 44 had stable non-IPF, and (D) 11 had an exacerbation of non-IPF. The CO-Hb concentrations of these subjects were (A) 1.5±0.5%, (B) 2.1±0.5%, (C) 1.2±0.4%, and (D) 1.7±0.5%. The CO-Hb concentration was positively correlated with the serum levels of surfactant protein (SP)-A (r=0.38), SP-D (r=0.39), and the inflammation index (calculated from HRCT; r=0.57) and was negatively correlated with the partial pressure of oxygen in the arterial blood (r=-0.56) and the predicted diffusion capacity of carbon monoxide (r=-0.61). The CO-Hb concentrations in subjects with a negative heart sign on 67Ga scintigraphy were higher than those in subjects without a negative heart sign (1.4±0.5% vs. 1.1±0.3%, p=0.018). Conclusion The CO-Hb levels of subjects with ILD were increased, particularly during an exacerbation, and were correlated with the parameters that reflect pulmonary inflammation.

Epidemiology, pathophysiology, clinical evaluation, and treatment of carbon monoxide poisoning in child, infant, and fetus.

Carbon monoxide (CO) poisoning is one of the most common types of poisoning causing death worldwide. In our country, it occurs particularly during winter as a result of leak from stove or water heater, or as result of inhalation during a fire. Although most poisonings occur accidentally, some cases are suicide attempt. As CO is a substance that is not visible and has no taste or smell and is therefore difficult to detect, the gas can be a “silent killer” that is not noticed until effects develop. CO reacts with oxygen, creating carboxy hemoglobin (COHb), which leads to tissue hypoxia. In addition, it has direct effect of causing cellular damage. Although symptoms of acute poisoning are most commonly observed in patients admitted to emergency rooms, effects of chronic exposure to CO can also seen. Clinically, although it affects all organ systems, involvement of central nervous system (CNS) and cardiovascular system is predominant. Most common poisoning symptoms are weakness, dizziness, headache, nausea, and nonspecific flu-like symptoms, like vomiting. Depending on severity of exposure, seizures, syncope, and arrhythmia may also be observed. In pregnant women, fetus can be harmed with relatively low level of COHb. Poisoning in infants has a more severe course than seen in other age groups. Symptoms must be associated with cause of poisoning, and careful anamnesis and treatment must be conducted quickly. Oxygen is the antidote for CO. It is administered through a mask in the form of normobaric oxygen therapy or through specific devices in the form of hyperbaric oxygen therapy. In this review, clinical data and current diagnostic and therapeutic approaches concerning CO poisoning are discussed.

Effect of genetic variants of bilirubin metabolism on the degree of hyperbilirubinemia in African-American newborns.

The objective of our study was to measure the effect of genetic variants of these two enzymes, UGT1A1 and SLCO1B1, in the bilirubin metabolic pathway on the degree of hyperbilirubinemia in a cohort of African-American (AA) infants from our well-baby nursery. In addition, a second objective was to document the types and frequencies of genetic variations of these enzymes in our cohort. A prospective study of 180 AA infants from the Well Baby Nursery of an inner city community hospital, all of whose mothers were type O pos. Sixty infants were ABO-incompatible direct antiglobulin test (DAT) pos, 60 were ABO-incompatible DAT neg and 60 were type O+. Blood for carboxyhemoglobin (COHb) and variants of the enzymes uridine diphosphoglucuronosyltransferase 1A1 and hepatic solute carrier organic anion transporter 1B1 (SLCO1B1) was drawn at the time of the infants' initial bilirubin, and the infants' precise percentile on the Bhutani nomogram was calculated. Variants in the two enzymes studied were quite common. In total, 21.1% were positive for a Gilbert phenotype, whereas an additional 42.4% were heterozygous for the *28 or *37 variant of UGT1A1. In total, 67.2% were homozygous for the *60 variant of the phenobarbital responsive enhancer module. In total, 41.1% were homozygous for the *1b variant of SLCO1B1, whereas an additional 12.7% were positive for the *4 variant of this gene. In total, 20.6% of infants had variations in both genes. Using logistic regression when COHbc was assessed with each of the different variants, only COHbc (P<0.0001 to 0.0004) was significantly associated with the level of hyperbilirubinemia as defined by the Bhutani nomogram. Although we have found quite a large number of genetic variants of the UGT1A1 and SLCO1B1 genes in the AA population, it does not appear that they have a significant impact on the incidence of hyperbilirubinemia among this group of infants.

Air quality index from charcoal production sites, carboxyheamoglobin and lung function among occupationally exposed charcoal workers in South Western Nigeria.

Charcoal production is often accompanied with gaseous and particulate emission into the atmosphere and occupationally exposed workers could be affected. This cross sectional comparative study was carried out to assess the levels of carbon monoxide (CO), carbon dioxide (CO2), sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter (PM2.5) generated during the phases of charcoal production and their relationship with certain biomarkers among charcoal workers (subjects) and non-charcoal workers (controls) such as carboxyhaemoglobin (COHb), forced expiratory volume in the first second of expiration (FEV1), peak expiratory flow rate (PEFR) and body mass index (BMI) in Igbo-Ora, Oyo State and Alabata, Ogun State, which are two of the major hubs of charcoal production in South Western Nigeria. Four communities in Igbo-Ora and six communities in Alabata were purposively selected and levels of pollutant gases were assessed using appropriate gas meters, PM2.5 was assessed with Thermo Scientific MIE pDR-1500, FEV1 and PEFR were measured with Piko-1 spirometer while COHb was assessed using non-invasive pulse CO-oximeter (Rad 57). Data were statistically analyzed and results were compared with recommended guidelines. The mean FEV1, PEFR, COHb and BMI for subjects and controls were 2.35 ± 0.73 and 2.69 ± 0.56, 253.72 ± 103.45 and 330.02 ± 94.61 (p < 0.01), 13.28 ± 3.91 and 8.50 ± 3.68 (p < 0.01) and 21.97 ± 2.19 and 23.36 ± 3.74 (p < 0.05) respectively. There was a statistically significant difference between actual and expected values of FEV1 (p < 0.01) and PEFR (p < 0.01) among charcoal workers. There existed a positive correlation between CO and COHb while FEV1 and PEFR correlated negatively with PM2.5. The study showed that charcoal workers are exposed to high levels of CO and PM2.5, contributing to lowered respiratory functions for FEV1 and PEFR and high levels of COHb compared to the control group. Routine respiratory and carboxyheamoglobin assessment of persons involved in charcoal production is also recommended.

Evaluating ECG and carboxyhemoglobin changes due to smoking narghile

Purpose: This study aimed to investigate whether increased carboxyhemoglobin (COHB) levels and ECG changes, which associated with fatal ventricular dysrhythmias, including increased QT, P-wave and T peak (Tp)-Tend (Te) dispersion, can be detected after smoking narghile, which is a traditional method of smoking tobacco that is smoked from hookah device.Materials and methods: After local ethics committee approval, this prospective study was conducted using healthy volunteer subjects at a “narghile café,” which is used by people smoking narghile in an open area. Before beginning to smoke narghile, all subjects’ 12-lead electrocardiographs (ECG), measurements of COHB levels, and vital signs were recorded. After smoking narghile for 30 min, the recording of the 12-lead ECGs and the measurements of COHB level and all vital signs were repeated.Results: The mean age of subjects was 26.8 ± 6.2 years (min-max: 18–40), and 28 subjects (84.8%) were male. Before smoking narghile, the median value of subjects’ COHB levels was 1.3% (min-max: 0–6), whereas after smoking, the median value of COHB was 23.7% (min-max: 6–44), a statistically significant increase (p < 0.001). Analysis of the subjects’ ECG changes after smoking narghile showed that dispersions of QT, QTc, P-wave and Tp-Te were increased, and all changes were statistically significant (p < 0.001 for all parameters).Conclusion: Although, especially among young people, it is commonly thought that smoking narghile has less harmful or toxic effects than other tobacco products. The results of this study and past studies clearly demonstrated that smoking narghile can cause several ECG changes - including increased QT, P-wave and Tp-Te dispersion - which can be associated with ventricular dysrhythmias.

Light irradiation for treatment of acute carbon monoxide poisoning: an experimental study

BackgroundBecause treatment modalities for carbon monoxide (CO) poisoning, especially normobaric oxygen and hyperbaric oxygen therapies, have limited effects and hyperbaric oxygen is not available at the scene where treatment is most needed, we conducted a study to determine and compare rates of carboxyhemoglobin (COHb) dissociation achieved in human in vitro blood samples under light radiation emitted at three levels of illuminance. This was done with a view toward eventual on-site application.MethodsWe drew blood from 10 volunteers, prepared 10 red blood cell solutions, and subjected each solution to a CO bubbling procedure to increase the COHb saturation. Samples of each bubbled solution were then divided between 3 beakers (beakers A, B, and C) for a total of 30 beakers. The solution in each beaker was exposed to a continuous flow of oxygen at 50 mL/min, and simultaneously for a period of 15 min, the beaker A and B solutions were irradiated with light emitted at 500,000 and 100,000 lux, respectively, from a halogen light source. The beaker C solutions were exposed to room light. At 3, 6, 9, 12, and 15 min, a 50-μL sample was pipetted from each of the 30 beakers for determination of its light absorbance and the COHb dissociation rate.ResultsUnder each of the experimental conditions, dissociation progressed but at different rates, and starting at 3 min, the differences in rates between conditions were significant (P < 0.01). The dissociation rate was greatest with light emitted at 500,000 lux.ConclusionsOur results point toward the possibility of readily performed, acute photodissociation therapy for patients with CO poisoning.

Carbon monoxide exposure among police officers working in a traffic dense region of Southern India.

Currently, in India, air pollution is widespread in urban areas where vehicles are major contributors. The aim of this study was to investigate the level of exposure in traffic police officers exposed to vehicle exhaust for less than 8 h/day. The specific objective of the study was to determine the levels of carboxyhaemoglobin (COHb) in these officers. The effect of exposure for 8 h/day is known, but shorter durations of chronic exposure need to be investigated, and there is a need to explore the policy options in this exposed population. This cross-sectional study, included non-smoking traffic police officers between 30 and 50 years of age working for more than 2 years in busy traffic junctions. The cases were sex matched with controls of same age group, working in offices at a teaching hospital. Venous blood was collected at the end of 3 h of duty for estimation of COHb among both the groups. The COHb levels were expressed as percentage values. Differences between the COHb levels among the traffic police officers and office workers were analysed using the Mann-Whitney U test and considered significant at p < 0.05. Traffic police officers had significantly elevated COHb levels compared with the controls; 76.5% of traffic police officers had COHb >2.5% compared with no office workers at this level and 41.2% of the police officers had COHb levels >4%. Overall, 53.8% of officers with COHb >2.5% reported headaches compared with 15.8% of officers with COHb <2.5%.