Carboxyhemoglobin Levels Research Articles

Carbon Monoxide Poisoning: The Great Imitator

Carbon Monoxide (CO) is one of the leading causes of poison deaths in the United States. Signs and symptoms are clinically variable secondary to inconsistent targeting of highly metabolic tissues by the gas. We report a case of a man in his early to mid-30’s presenting to the emergency department with mental status changes, fatigue, headache, and flu-like symptoms for three days. The patient had been working on his motor vehicles in the garage during this time, using a portable diesel powered space heater to keep warm. Subsequent neurology and cardiology workup demonstrated bilateral globus pallidus (GP) lesions on brain imaging, increased non-myocardial infarction troponin levels, carboxyhemoglobin (COHb) level of 3.8%, elevated liver enzymes, and acute kidney failure. In this setting of his delayed presentation as a smoker with carbon monoxide poisoning, carboxyhemoglobin levels alone become less reliable. This report investigates the use of bilateral GP lesions, the most frequently affected structure, as well as damage preference to highly metabolic tissues to assist in diagnosis and prognosis for CO poisoning. Our observations can be used for further study of the relationship between bilateral GP necrosis and initial presentation and outcome of patients experiencing CO poisoning leading to earlier recognition, treatment, and decreased morbidity/mortality.

Carbon Monoxide-Releasing Molecule-2 Inhibits Connexin 43-Hemichannel Activity in Spinal Cord Astrocytes to Attenuate Neuropathic Pain.

Carbon monoxide-releasing molecule (CORM-2) acts as a carbon monoxide (CO) deliverer in a more controlled manner without altering carboxyhemoglobin level and exerts potential function in inhibiting inflammation and/or acute nociception. However, the regulatory mechanism of CORM-2 on spinal nerve ligation (SNL)-induced neuropathic pain is not currently clear. Our study aims to investigate the role of CORM-2 in neuropathic pain and the underlying mechanism. We found that spinal cord astrocytes were dramatically activated on day 7 after SNL. L-α-aminoadipate (L-α-AA), an astroglial toxin, reversed SNL-induced astrocyte activation at sub-toxic dose. Intrathecal administration of CO donor CORM-2 induced antiallodynic and antihyperalgesic effects in neuropathic animals induced by SNL and suppressed SNL-induced spontaneous excitatory postsynaptic current (EPSC) frequency in lamina II neurons of spinal cord slices. CORM-2 administration markedly inhibited SNL-induced connexin 43 (Cx43) expression, hemichannel function, and gap junction function on spinal astrocyte membranes. Moreover, exogenous CORM-2 could attenuate HO-1 expression, while overexpressed heme oxygenase-1 (HO-1) increased intracellular CO production, attenuated Cx43 expression, hemichannel function, and gap junction function on spinal astrocyte membranes. Additionally, Cx43 over-expression markedly reduced CORM-2-induced mechanical threshold and thermal hyperalgesia and elevated CORM-2-induced spontaneous EPSC frequency. In conclusion, CORM-2 attenuated SNL-induced neuropathic pain via suppressing Cx43-hemichannel function, which may contribute to understanding of the pathology of neuropathic pain.

Evaluation of cardiac autonomic function using heart rate variability in children with acute carbon monoxide poisoning.

The present study included 40 children aged 1-17 years who were admitted to the Pediatric Intensive Care Unit with acute carbon monoxide poisoning and 40 healthy age- and sex-matched controls. Carboxyhaemoglobin and cardiac enzymes were measured at admission. Electrocardiography was performed on admission and discharge, and 24-hour Holter electrocardiography was digitally recorded. Heart rate variability was analysed at both time points - 24-hour recordings - and frequency domains - from the first 5 minutes of intensive care unit admission. Time domain and frequency indices such as high-frequency spectral power and low-frequency spectral power were similar between patient and control groups (p>0.05). The ratio of low-frequency spectral power to high-frequency spectral power was significantly lower in the carbon monoxide poisoning group (p<0.001) and was negatively correlated with carboxyhaemoglobin levels (r=-0.351, p<0.05). The mean heart rate, QT dispersion, corrected QT dispersion, and P dispersion values were higher in the carbon monoxide poisoning group (p<0.05) on admission. The QT dispersion and corrected QT dispersion remained longer in the carbon monoxide poisoning group compared with controls on discharge (p<0.05). The frequency domain indices, especially the ratio of low-frequency spectral power to high-frequency spectral power, are useful for the evaluation of the cardiac autonomic function. The decreased low-frequency spectral power-to-high-frequency spectral power ratio reflects a balance of the autonomic nervous system, which shifted to parasympathetic components.

長期的な高圧酸素療法が社会復帰に奏効したと思われる間歇型一酸化炭素中毒の1例(A case of delayed encephalopathy after recovery from acute carbon monoxide poisoning through repetitive hyperbaric oxygen therapy)

間歇型一酸化炭素（carbon monoxide: CO）中毒は遅発性脳症（delayed encephalopathy: DE）とも呼ばれ，治療法は確立されておらず，重度の後遺症を残す症例も多い。DEに対し，長期的な高圧酸素療法（hyperbaric oxygen therapy: HBOT）を施行し，社会復帰を得た症例を経験したので報告する。症例は30歳の女性。家族が自宅ガレージに駐車後エンジンを停止するのを忘れており，翌日上階室内で意識消失しているところを発見された。来院時，GCS 8の意識障害を認め，CO–Hb 32%で急性CO中毒と診断した。気管挿管を実施し，100%平圧酸素投与と48時間の脳低温療法を施行した。CTで淡蒼球の低吸収化，MRIで前頭葉大脳白質に高信号を認めた。その後第19病日までに意識は元の状態まで回復したが，第32病日に突然，無表情となり不隠行動と失禁がみられ，第35病日に立位や嚥下が困難となり，意思疎通も不能となった。DEを発症したと考え，2.0気圧，60分間でHBOTを開始した。3か月間で計60回行ったところ，徐々に神経所見が改善し，大きな後遺症を残すことなく退院となり社会復帰した。DEに対するHBOTの有効性を示す大規模研究はないが，本症例では長期的なHBOTが著効した印象が強く，重度のDEにおいて症状が進行しても長期治療すべき症例があると考えられた。 Delayed encephalopathy (DE) after acute carbon monoxide (CO) poisoning is a disease with a poor prognosis. There is no established treatment for DE, and no evidence that hyperbaric oxygen therapy (HBOT) is beneficial in DE. A 30–year–old female presented with severe CO poisoning. She was found unconscious and her carboxyhemoglobin level on admission was 32%. She was admitted to the intensive care unit, and immediately treated with mechanical ventilation with normobaric oxygen and brain hypothermia therapy. She regained consciousness 19 days later, and returned to her normal activities. However, 13 days later she became restless and developed incontinence. Her neurologic state began to deteriorate rapidly, progressing to akinetic mutism over the next week and finally she became less communicative. She was diagnosed with DE after CO intoxication. HBOT was conducted every day at 2.0 absolute atmosphere (ATA), each session lasting 60min, and gradual and progressive clinical improvement was observed. Her condition gradually improved over the next three months and she regained independence in her activities of daily living. She also showed significant improvement in neurocognitive function. HBOT appears useful in treating DE patients. 倫理規定に関する事項は次の通りである。 ①倫理委員会が審査・承認すべき事項には該当しない。 ②個人情報保護に基づき，匿名化している。 ③患者および家族より論文の掲載に関して同意を得ている。 急性一酸化炭素（carbon monoxide: CO）中毒の経過において，数日から数週間後に見当識障害，認知機能障害，運動失調，無言無動などの特徴的な神経症状が出現する症例があり，間歇型CO中毒，あるいは遅発性脳症（delayed encephalopathy: DE）と呼ばれる。急性CO中毒の10～30%に発症すると報告 1されているが，明確な治療方法は確立されておらず，重度の後遺症を残す症例も多い。また，DEの発生は遅発性のため，急性期施設である救命救急センターにおいて救急医が経験する機会は少ない。 今回，救命救急センター入院中にDEを発症し，長期的な高圧酸素療法（hyperbaric oxygen therapy: HBOT）を施行し，完全に社会復帰した症例を経験したので報告する。 患 者：30歳の女性。対人恐怖症があり，自宅2階で十数年間ひきこもり生活をしていた。その他既往歴なし。7月某日，自室の直下にある1階ガレージでシャッターを閉めたまま家族が車のエンジンを停止し忘れた。24時間後に自室のソファ上で意識がない状態で発見されて救急搬送となった。 来院時現症：意識レベルJCS II–30，GCS 8（E2V2M4），心拍数138/分，血圧133/90mmHg，呼吸数22/分，SpO2 97%（リザーバーマスク酸素10L/min投与下）。嘔吐痕と失禁を認めた。搬入時の動脈血ガス分析はCO–Hb 32%であり急性CO中毒と診断した。高乳酸血症（乳酸値10.3mmol/L）を伴う代謝性アシドーシスを合併していた。血液検査所見は白血球数高値のほか，高アミラーゼ血症，高CPK血症を認めた（Table 1）。 来院後経過（Fig. 1）：意識障害と誤嚥による呼吸不全のため気管挿管を実施し，頭部CT検査を行ったところ脳腫脹を認めたため，ICU入室後に48時間の脳低温療法（35℃）を施行した。急性期CO中毒に対して，乳酸値が正常化するまで，100%酸素を約40時間投与した。誤嚥性肺炎は抗菌薬投与と人工呼吸管理で改善した。従命反応可能なレベル（GCS：E4VtM6）まで意識が改善したため，第12病日に気管チューブを抜去したが仮性球麻痺を認め，第13病日に誤嚥防止のため気管切開術を施行した。第19病日に意識清明となり，第30病日には仮性球麻痺も改善し，気管切開チューブを抜去した。その後リハビリテーションを継続していたが，第32病日に突然，失禁，無表情，不隠行動，不随意運動が出現した。その後症状は悪化し，立位困難，嚥下障害，無言無動を呈し，意思疎通ができなくなった。症状からDEを発症したと考え，第35病日よりHBOTとステロイドパルス療法を開始した。HBOTは2気圧（ATA）60分間を1日1回平日に施行した。ステロイドパルス療法はmethylprednisolone 1gを3日間投与した。嚥下障害に対して胃瘻造設を施行し経腸栄養を行った。その後HBOT施行20回目に従命反応が出現し，22回目には発語を認めた。27回目で意識清明となり，経口摂取が可能となった。29回目で排尿が自立し，43回目で歩行が可能となった。症状の改善効果が固定したと判断するまで，HBOTは合計60回，3か月間実施した。退院前の高次脳機能検査ではmini–mental status examination（MMSE）＝25，Wechsler adult intelligence scale（WAIS）–III＝（全検査IQ69，言語性IQ85，動作性IQ59）と若干の低下は認めたが，入院から4か月後に独歩退院となった。 Clinical course from admission to discharge. ＜経過中の検査所見＞ 頭部CT：第4病日に来院時にはなかった両側淡蒼球の濃度低下が出現し，その所見は退院まで変化が認められなかった（Fig. 2）。 Brain CT series, brain MRI series and brain SPECT series. 頭部MRI（FLAIR，DWI）：第7病日に撮像された頭部MRIでは両側の淡蒼球と前頭葉の深部白質に高信号を呈した。DE発症直前の第29病日ではさらに白質病変が拡大したが，第92病日のMR–FLAIR画像では前頭葉の軽度萎縮を認める一方，深部白質の高信号病変は縮小した（Fig. 2）。 SPECT（123I–IMP脳血流シンチグラム)：初回（第36病日）のSPECTでは全般的な脳血流低下を認めたが，第62病日の両前頭葉の局在的な血流低下を経て，第92病日には左前頭葉と左側頭葉内側領域に明らかな血流改善を認めた（Fig. 2）。 脳波検査：第62病日の脳波では全般性の持続性低振幅徐波が認められ，重度のびまん性脳症を示唆した。第92病日の脳波における前頭部の律動性δ波と第121病日の脳波における持続性不規則徐波は前頭葉の脳機能低下を示唆したが，同時にα帯域の後頭部優位律動が徐々に回復しており，SPECTの変化にも一致した（Fig. 3）。 Electroencephalogram series. DEはCO暴露数日から数週間の意識清明期（lucid interval）後に，異常行動，人格変化，高次脳機能障害などの精神神経症状や歩行障害，パーキンソニズムなどの運動機能障害を来すことにより診断される。病理学的には大脳白質のミエリンやオリゴデンドログリアの損傷による脱髄性白質脳症といわれており 2，機序は酸素欠乏後の酸素再供給に伴う活性酸素発生や免疫系の関与を指摘されている 3。 DEは急性CO中毒の10～30%に発症するとされており，発症予測因子の研究では，Pepeら 4は初期の意識レベルGCS 8以下（オッズ比7.15）と搬入時白血球数10,000/µL以上（オッズ比3.31）の症例で有意に発症率が増加していたと報告しており，Parkinsonら 5のMRIを使用した研究においては，DE発症には大脳白質病変が必発であると報告している。一方で淡蒼球病変の有無はDE発症に関与しないとされている。本症例では初期の意識レベルGCS 8以下，搬入時白血球数10,000/µL以上，MRIの大脳白質病変すべての発症予測因子を満たしていた。本症例でDE発症の可能性が高かったことを考えると，発症を念頭に置いた経過観察が必要であったが，一方で発症時期については数日から数週間と幅があり，どの程度の経過観察期間が必要かに関して明確な基準はない。近年のDEに対してHBOTを施行した症例の検討で，予後良好群は，若年，意識清明期が長い，肺炎の合併がない，最も状態が悪化したときのADLが悪くないことを報告しているが，予後良好群の平均間歇期間は25.9±6.5日であった 6。いつまで急性期病院で経過観察すべきかの議論は別として，発症予測因子がある場合には1か月程度はDEを発症する可能性を考えた経過観察が必要であろう。 DE発症予防に対する急性期治療の効果についても明確ではない。CO中毒に対する急性期のHBOTは，DEを予防するという報告 7がある一方，平圧療法と比較して1か月後の社会復帰率やDEの予防効果に差はないとする報告 8もあり，議論の分かれるところである。当施設では人工呼吸管理中の患者は安全を考慮して急性期のHBOTは施行せず，平圧高濃度酸素療法を行っている。また，Kamijoら 9は急性CO中毒に脳低温療法を施行した症例報告により脳低温療法はDEを予防する可能性があることを示唆しているが，本症例では脳低温療法を施行したものの，DEを発症した。DE予防のための急性期脳低温療法に関しては今後の検討が必要と考えられる。 DE発症後のHBOTの有効性に関しては，RCTを含めた大規模研究は施行されておらず，未だ定説は得られていないが，長期間施行することで有効とする報告 10もある。DE自体は自然回復するのか不明であるが，我々の経験した症例ではHBOT 20回目から神経学的な回復がみられ，画像所見も改善を認めたため，HBOTが非常に効果的であった印象がある。本症例のようにADLや認知機能が著しく低下しても，諦めずに長期間のHBOTを試みる価値があると考えられる。HBOTの実施期間に関しては明確な基準はないが，本症例を経験して，土居らの報告 11のように症状が固定したと判断するまで長期的に続けるべきという意見に賛同する。HBOTのDEに対する機序は，大脳灰白質にある神経細胞が残存しているうちに，白質にある髄鞘の再生を促進するとともに，神経細胞自体に保護的作用を発揮すると推測される。本症例では20回ごとに治療効果判定と継続判断を行った。ステロイドパルス療法もDEの改善に効果的な可能性が示唆されており 12，oligodendrocyteの保護あるいは分化を促進することで髄鞘の再生を促す機序，あるいはステロイドの各種抗炎症作用によるといわれているが，本症例での有効性については不明であった。また早期のリハビリテーションも重要である。 本症例では経時的に画像検査を施行することができ，HBOTの治療効果を視覚的に確認し得た。CT所見はHBOT後の変化はみられなかったが，MRI所見は若干の改善傾向を認めた。SPECTでDE発症時に前頭葉の血流低下が認められることが報告 13されているが，本症例では頻回のHBOT後に著明な血流改善所見を認めた。SPECTでの脳血流の変化から脳細胞代謝や脳細胞機能低下は不可逆的ではなく，HBOTにより改善しうることが示唆された。本症例でHBOTによりMRI，SPECT，および脳波所見の改善を認めたため，HBOT継続判断には臨床症状にこれらの検査所見も加えて，検査所見の改善傾向を認めるうちは治療を継続すべきと考える。 重度のDEにおいても神経学的な回復を見込める症例も存在するため，複数回のHBOTの適応を積極的に検討すべきである。その適応や継続の判断には神経生理学的検査や脳画像診断は有用である。搬入時昏睡の重症例やDE発症リスクをもつ患者に対しては危険性を十分に説明し厳重な経過観察をすべきである。 本論文に関連して開示すべき利益相反はない。

Normal carboxyhaemoglobin level in carbon monoxide poisoning treated with hyperbaric oxygen therapy

Throughout the world both intentional and inadvertent exposure to carbon monoxide (CO) remains an important public health issue. While CO poisoning can be lethal, the morbidity is predominantly due to...

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.

Carbon monoxide poisoning in 3 year old with atypical MRI imaging

Objective: Carbon monoxide (CO) as a source of poisoning in children has been described as a 'silent killer'. We report a young child who suffered from smoke inhalation and whose imaging is atypical with no involvement of the globus pallidus as is characteristic of CO toxicity. Methods: This is a single case report describing the clinical and MRI findings of a 3 year old boy caught in a house fire. The origins of the fire are unclear but led to other family members also being hospitalized. Our patient was the most severely affected with a Glasgow Coma Score of 3 on arrival of the Emergency services following a trauma call. He was found unconscious and covered in soot but had not sustained external burns. Onsite carboxyhaemoglobin level was 30% and led to treatment with hydroxycobalamin. Laryngeal oedema was present during intubation. Our patient was ventilated for 6 days. His stay on PICU was marked by minimal inotropic support, stable ventilatory requirements and jitteriness during the weaning phase of his sedation. Short-term outcome at 6 months shows him to have attention and behavioural problems more marked than his premorbid state, but with no apparent motor deficits. Results: A brain CT scan done on immediate arrival in Accident & Emergency department showed some evidence of brain swelling and subtle low attenuation within the caudate heads bilaterally. A 3 Tesla brain MRI scan done on day 8 showed: - bilateral symmetrical hyperintensity of the caudate nuclei and putamina only, with no cortical or white matter abnormalities. Conclusion: The characteristic imaging findings in cases of CO poisoning in the literature almost always appear to involve the globus pallidus bilaterally, with very occasionally some involvement of the caudate and/or putamen. This case highlights that pallidal involvement is not a prerequisite imaging feature.

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.

PP11 - Effect of cardiopulmonary bypass on carboxyhemoglobin levels in smokers and non-smokers undergoing various cardiac surgical procedures

PP11 - Effect of cardiopulmonary bypass on carboxyhemoglobin levels in smokers and non-smokers undergoing various cardiac surgical procedures

Indications of early intubation for patients with inhalation injury.

AimFor patients with inhalation injury, the indications for early intubation are diverse. The purpose of this study was to identify the most reliable symptoms, physical findings, and medical examinations with which to determine the indications for early intubation in patients with inhalation injury.MethodsWe retrospectively collected patient data from medical records. Collected data included age, sex, burn size, symptoms, physical findings, carboxyhemoglobin levels (COHb), and bronchial wall thickness (BWT) determined from chest computed tomography images. We analyzed the relationships between these findings and the early intubation. We performed fiberoptic bronchoscopy in all patients, and analyzed the relationships between bronchoscopic severity and other findings.ResultsOf the 205 patients, 80 patients were diagnosed as having inhalation injury, and 34 patients were intubated. Burn size, facial burns, neck burns, use of accessory respiratory muscles, and COHb seemed to be related with intubation, whereas singed nasal hair was not. If the patients suffered ≥27% total body surface area burn and BWT ≥3.5 mm, the positive predictive value for early intubation was 1.00. If the patients suffered smaller cutaneous burn without neck burn, and their COHb <4.0%, the negative predictive value for early intubation was 0.97. Fiberoptic bronchoscopy findings from above the glottis were mainly related with patients’ symptoms. Findings from below the glottis were mainly related with BWT and COHb.ConclusionsPatients’ symptoms, especially use of accessory respiratory muscles, are reliable, and BWT and COHb are also useful tools, for determining the indication for early intubation.

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.

Is Level of Serum Ischemia-Modified Albumin A Useful Biomarker in Carbon Monoxide Poisoning Cases?

Ischemia-modified albumin (IMA) is an emerging diagnostic biomarker for many ischemic conditions. The study was conducted to investigate whether there is a change in IMA levels in carbon monoxide poisoning and, if so, the clinical relevance of IMA levels. This study was performed between October 2013 and April 2014 to compare levels of serum IMA drawn at the time of admission to the emergency department in 49 patients poisoned with carbon monoxide and 37 healthy controls. Serum IMA, blood carboxyhemoglobin, and lactate levels were analyzed. Ischemia-modified albumin levels of patients with carbon monoxide poisoning were higher than those of controls. In patient group, however, there was no correlation between serum IMA and carboxyhemoglobin levels (r = -0.244, P > 0.05), whereas a negative correlation was detected between serum IMA and lactate levels (r = -0.334, P < 0.05). After all, a positive correlation was present between carboxyhemoglobin and lactate levels (r = 0.399, P < 0.05). Results from this preliminary study suggest that IMA might have diagnostic value in carbon monoxide poisoning and may be a parameter to be used clinically together with carboxyhemoglobin levels in terms of reflecting tissue hypoxia. In addition, IMA may be a criterion, especially in delayed cases where carboxyhemoglobin level may be normal in deciding hyperbaric oxygen treatment. To clarify this issue, further studies with larger population are needed.

Fire deaths – a review and an experimental investigation of post-mortem formation of carboxyhaemoglobin

The forensic investigation of deceased retrieved following a fire includes determining if death occurred before or during the event. A blood carboxyhaemoglobin level above 10% is considered indicative of respiration during a fire, implying that an individual was not deceased before the event. Previous spectroscopic studies have revealed that oxygen can passively diffuse through the skin and re-oxygenate haemoglobin. It was therefore questioned if carbon monoxide could also dermally diffuse and elevate post-mortem blood carboxyhaemoglobin levels, which could falsely insinuate that an individual had been alive and respired during a fire. Exposing both oxygenated and deoxygenated forms of haemoglobin to carbon monoxide converted them to carboxyhaemoglobin. This was measured using an ISP-REF Integrating sphere coupled to a USB spectrometer by fibre optic probe. Stillborn piglets were exposed to carbon monoxide to show that the gas can passively diffuse through the skin, resulting in formation of carboxyhaemoglobin in hypostasis, which was confirmed by observing a shift in the absorption spectrum. Piglets with significant cavity breaches, as could be found in cases with extensive stab/bullet wounds or heat defects, exposed to carbon monoxide demonstrated cavity carboxyhaemoglobin levels above 10% which could falsely suggest respiration of carbon monoxide had occurred.

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.

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.

Copeptin levels in carbon monoxide poisoning

The aim of this study is to identify the copeptin levels in patients presenting with carbon monoxide (CO) poisoning to the emergency department and to investigate its correlation with the neurological effects. The study group consisted of patients presenting with CO poisoning and carboxyhemoglobin levels >10%. Blood samples for copeptin levels were obtained twice, first at presentation then at the fourth hour of observation. The data were analyzed using SPSS 16 for Windows. The median copeptin levels of the patient group were identified as 0.63 (0.39-1.06) ng/mL at hour 0 and 0.41 (0.31-0.49) at hour 4. The copeptin levels of the control group were 0.34 (0.25-0.42) ng/mL and were significantly lower than those of the patient group (P < 0.000). According to our results, 0.345 ng/mL for plasma copeptin level as the best cut-off level may be used with sensitivity of 94.0% and specificity of 60%. The copeptin levels at hour 0 were statistically significantly higher in the neurologically affected patients than those not affected (P < 0.001). In this study it was shown that blood copeptin levels increase in patients presenting to the emergency department with CO poisoning.

Фізико-хімічні властивості лігандних форм гемоглобіну за експериментального стрептозотоцинового цукрового діабету й за алкогольної інтоксикації

The study of hemoglobin affinity to oxygen, oxygen capacity and the content of ligand forms has been conducted in hemolyzates of rat peripheral blood at chronic alcohol intoxication models and experimental diabetes mellitus. The findings revealed that at alcohol intoxication both hemoglobin affinity to oxygen and hemoglobin oxygen capacity validly decrease, whereas at experimental streptozotocin-induced diabetes hemoglobin the affinity to oxygen increases and oxygen capacity is quite high. The results of study demonstrated that sulf- and methemoglobin levels rise under alcohol intoxication and sulf-, met- and carboxyhemoglobin levels rise under experimental diabetes mellitus. We have also undertaken study of hemoglobin affinity to oxygen, oxygen capacity and the ratio of hemoglobin ligand forms in alcoholics and healthy donors. A valid increase in sulf- and methemoglobin and a decrease in hemoglobin affinity to oxygen in alcoholics (32.50±0.45 versus 28.60±0.54 mm Hg in the control group) with insignificant changes in oxygen capacity were revealed. Since minor ligand forms contribute to the affinity of total hemoglobin to oxygen, their quantitative characteristics are essential. Thus, data on absorption spectra which characterize nitrosyl-hemoglobin ligand form and transition of deoxy- and methemoglobin into nitrosyl-hemoglobin have been collected. A combined absorption spectrum of nitrosyl-hemoglobin has been built based on the statistical data set deoxyhemoglobin and its full transition into nitrosyl-hemoglobin (60 analyses) in the examined wavelength range. The article provides the results of the comparative analysis of electronic absorption spectra characteristic peaks of six hemoglobin ligand forms taken from peripheral blood in healthy donors in 450–750 nm wavelength range. The studies can be a pre-requisite for the development of methods for determining six hemoglobin ligand forms in a single blood sample.

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.

THE ANALYSIS OF CARBON MONOXIDE POISONING CASES PRESENTED TO THE EMERGENCY DEPARTMENT OF A UNIVERSITY HOSPITAL

Introduction : Carbon monoxide poisoning is one of the most leading poisoning causing death through worldwide, although its exact incidence is yet to be determined. Carbon monoxide is a colorless and odorless gas that binds to hemoglobin and cellular oxidative enzymes with a higher affinity than oxygen, causing tissue hypoxia. Hypoxia of heart and nervous system cells leads to neuropsychiatric and cardiological signs and symptoms. In this study, we aimed to investigate the demographic characteristics of the carbon monoxide poisonings occurring in patients presenting to the emergency department. We also aimed to determine the clinical characteristics, and the factors affecting the mortality. Material and Methods : We retrospectively reviewed the demographic and clinical characteristics of 1013 patients who admitted to our adult emergency department and were diagnosed with carbon monoxide poisoning for a period of two years. We recorded and analyzed age, gender, season of presentation, hospital admission rate, sources of poisoning, symptoms at admission, mortality rate, and carboxyhemoglobin and cardiac Troponin-I levels. Results : The mean age of the study population was 36.2±16.2 years. 70.5% of the patients were admitted in winter seasons. 66.1% of the patients’ poisoning source was water heater and stove. The most frequent symptoms were nausea, headache, and dizziness. On multilogistic regression analysis the death rate was significantly correlated with age and cardiac Troponin I level. Conclusion : Our results indicate that accidental carbon monoxide poisonings continue to be an important public health problem in regions with cold winter seasons. We believe that intensifying efforts for public education and efficient control of resources of poisoning are the key steps to prevent carbon monoxide poisonings.

Carbon monoxide poisoning in Utah: 1996-2013

Introduction: The true incidence of carbon monoxide (CO) poisoning is not clearly known, but a description of possible trends could aid in prevention. Methods: Investigators searched Utah state databases for emergency department (ED) visits and admissions for CO poisoning and medical examiner records for CO-related fatalities. Results: From 1996-2013, 7,590 individuals were diagnosed with CO poisoning: 6,469 were treated/released from EDs; 596 were admitted; 525 died. Of 7,065 non-fatal poisonings, 5,950 (84%) were accidental and 498 (7%) were suicide attempts. Few patients (9.7%) were treated with hyperbaric oxygen. For accidental poisonings, internal combustion engines accounted for 43%, smoke inhalation, 34%, and heating sources, 22%. Internal combustion engines were implicated in 97% of suicide attempts. Non-fatal poisonings declined following a 2008 legislative change requiring CO alarms in residences, but we do not know if legislation caused the decline. One hundred forty-one (27%) fatal poisonings were accidental, 361 (70%) suicides and two (0.4%) homicides. Victims with cardiovascular autopsy findings/past cardiovascular history had lower carboxyhemoglobin levels (mean 51.2%, n=53) compared to those without (70.8%, n=472). Mean postmortem carboxyhemoglobin was highest in ages 20-29 years (72.5%). Conclusions: The incidence of CO poisoning in Utah is declining, but CO poisoning is still common. Alarm legislation may aid prevention efforts. An educational campaign addressing the many causes and circumstances of CO poisoning is required for prevention.