El rol del laboratorio en los hallazgos de intoxicación y exposición a monóxido de carbono / The role of the laboratory in findings of carbon monoxide poisoning and exposure

El monóxido de carbono es un gas altamente tóxico que se origina principalmente por la combustión incompleta de combustibles fósiles. La intoxicación presenta síntomas inespecíficos que solapan otras patologías y por lo tanto es indispensable la confirmación mediante la medición de la carboxihemoglobina en sangre. El laboratorio incorporó la determinación en el informe del estado ácido base a partir de octubre del 2018, debido a que previamente el médico debía solicitarla frente a la sospecha de una intoxicación. El objetivo del trabajo fue evaluar si esta medida implementada por el laboratorio contribuyó a mejorar el diagnóstico de intoxicación por CO, analizar las características de los pacientes con COHb mayor o igual a 5% y definir un valor de reporte inmediato para la COHb. El 46% de los casos con COHb mayor o igual a 5% no se relacionaban con una intoxicación y/o exposición a CO. De los casos de intoxicación se encontró que el 77% fueron diagnosticados a partir de la sospecha médica y un 23% por hallazgo del laboratorio. Se concluyó que es de mucha utilidad el rol del laboratorio en detectar aquellos casos que no fueron evidentes clínicamente. Existen ciertas patologías como las oncológicas o la enfermedad de Wilson donde se vieron valores elevados de COHb sin presentar intoxicación y se definió finalmente, como valor de reporte inmediato 7% para la COHb. (AU)

Carbon monoxide is a highly toxic gas that originates mainly from incomplete combustion of fossil fuels. Intoxication causes nonspecific symptoms that overlap with other conditions and, therefore, confirmation by measuring blood carboxyhemoglobin is essential. The laboratory incorporated the measurement in the acid-base status report as of October 2018, as it was previously required to be requested by the physician in case of suspected intoxication. The aim of this study was to evaluate whether this measure implemented by the laboratory contributed to the improvement of the diagnosis of CO intoxication, to analyze the characteristics of patients with COHb greater than or equal to 5% and to define an immediate reporting value for COHb. Overall, 46% of the cases with COHb greater than or equal to 5% were not related to CO poisoning and/or exposure. Of the cases of intoxication, 77% were diagnosed based on medical suspicion and 23% on laboratory findings. It was concluded that the laboratory has a useful role in detecting cases that were not clinically evident. There are certain diseases including different types of cancer or Wilson's disease where elevated COHb values were seen without intoxication and finally, 7% for COHb was defined as the immediate reporting value (AU)

Intoxicación por monóxido de carbono: estudio observacional de pacientes que acudieron a Urgencias durante 2020 / Carbon monoxide poisoning: an observational study of patients admitted to Emergency Department during 2020

El objetivo fue describir las intoxicaciones monóxido de carbono. Se diseñó un corte transversal que incluyó una muestra consecutiva de mediciones de carboxihemoglobina (COHb), realizadas Enero y Diciembre 2020 en la Central de Emergencias del Hospital Italiano de Buenos Aires. Se utilizaron bases secundarias y revisión manual de historias clínicas para recolección de varia-bles de interés. Durante el período de estudio hubo 20 pacientes confirmados, con media de 50 años (DE 20), 55% sexo masculino, 20% tabaquistas, y una única embarazada. El 70% correspondieron al trimestre Junio-Julio-Agosto. La fuente de intoxicación más frecuente se debió a accidentes domésticos (calefón, estufa, brasero, hornalla, salamandra) que representaron el 50% de los casos, 30% por incendios, y el 20% restante explicado por tabaco o factor desconocido. Los estudios de laboratorio más solicitados fueron: 95% recuento de glóbulos blancos, 85% glucemia, 70% CPK, y 55% troponina. Los hallazgos relevantes fueron COHb con mediana de 7.15%, CPK con mediana de 89 U/mL, y troponina con mediana de 8.5 pg/mL. La totalidad se realizó electrocardiograma: 15% presentaron arritmia como hallazgo patológico, y ninguno isquemia. En cuanto la presentación clínica: 30% presentó cefalea, 15% síncope, 15% coma, 10% mareos y 10% convulsiones. Sólo 25% tuvieron tomografía y 15% resonancia de cerebro, sin hallazgos críticos. Sin embargo, 15% fueron derivados para trata-miento con cámara hiperbárica. La mayoría ocurrieron en invierno y explicados por accidentes domésticos. Será necesario un fortalecimiento del rol preventivo que apunte al control de la instalación y el buen funcionamiento de artefactos, como mantener los ambientes bien ventilados (AU)

The objective was to describe carbon monoxide poisoning. A cross sectional was designed, which included a consecutive sample of carboxyhemoglobin (COHb) measurements, carried from January to December 2020 at the Emergency Department of tHospital Italiano de Buenos Aires. Secondary databases and manual review of medical records were used to collect variables of interest. During the study period there were 20 confirmed patients, with a mean age of 50 (SD 20), mostly male (55%), 20% smokers, and only one pregnant woman, 70% corresponded to June-July-August. The most frequent source of poisoning was explained to domestic accidents (water heater, stove, brazier, stove, salamander) which represented 50% of cases, 30% due to fires, and the remaining 20% by tobacco or unknown factor. The most laboratory studies were: 95% white blood cell count, 85% glycemia, 70% CPK, and 55% troponin. Meanwhile, relevant findings were carboxyhemoglobin with a median of 7.15%, CPK with a median of 89 U/mL, and troponin with a median of 8.5 pg/mL. All underwent an electrocardiogram: 15% presented arrhythmia as a pathological finding, and none ischemia. Regarding the clinical presentation: 30% presented headache, 15% syncope, 15% coma, 10% dizziness and 10% seizures. Only 25% had brain tomography and 15% MRI, without pathological findings. However, 15% were referred for treatment with a hyperbaric chamber. Most of the cases occurred in winter and explained by domestic accidents. It will be necessary to strengthen the preventive role that aims to control the installation and the proper functioning of devices, such as keeping rooms well ventilated (AU)

Changes of HbCO in the Blood of Rats with Different CO Concentration and Inhalation Time / 法医学杂志

OBJECTIVES@#To explore the change rules of behavioral characteristics, survival time and saturation of carboxyhemoglobin （HbCO） in different CO concentration to provide experimental basis for the cases of CO poisoning death in forensic practice.@*METHODS@#Total 160 SD rats were randomly divided into four groups. CO with the concentration of 1 250 mg/m³, 3 750 mg/m³, 6 250 mg/m³ were continuously and respectively replenished in a self-made toxicant exposure equipment until rats died from poisoning. In different CO concentration, the behavioral characteristics and survival time of poisoning rats were observed and recorded. The saturation of HbCO in heart blood was detected by spectrophotometric method. Organs such as brain, heart, lung and liver, and heart blood were obtained via autopsy and histopathological observation was performed.@*RESULTS@#The behavioral characteristics of CO poisoning rats were limp and slow response. There were a gradual decrease of survival time and an increase of HbCO saturation in rats with the increase of CO concentration. Three rats in CO concentration of 1 250 mg/m³ group showed lower saturations of HbCO than the lethal dose and this situation hasn't been found in other groups.@*CONCLUSIONS@#The animal model of CO poisoning established under different CO concentration has the advantages such as simplicity and good repeatability, which lays a foundation to the further study for CO and other inhaled toxic gas in the research of forensic sciences.

Serum bilirubin value predicts hospital admission in carbon monoxide-poisoned patients. Active player or simple bystander?

OBJECTIVES:Although carbon monoxide poisoning is a major medical emergency, the armamentarium of recognized prognostic biomarkers displays unsatisfactory diagnostic performance for predicting cumulative endpoints.METHODS:We performed a retrospective and observational study to identify all patients admitted for carbon monoxide poisoning during a 2-year period. Complete demographical and clinical information, along with the laboratory data regarding arterial carboxyhemoglobin, hemoglobin, blood lactate and total serum bilirubin, was retrieved.RESULTS:The study population consisted of 38 poisoned patients (23 females and 15 males; mean age 39±21 years). Compared with discharged subjects, hospitalized patients displayed significantly higher values for blood lactate and total serum bilirubin, whereas arterial carboxyhemoglobin and hemoglobin did not differ. In a univariate analysis, hospitalization was significantly associated with blood lactate and total serum bilirubin, but not with age, sex, hemoglobin or carboxyhemoglobin. The diagnostic performance obtained after combining the blood lactate and total serum bilirubin results (area under the curve, 0.90; 95% CI, 0.81-0.99; p<0.001) was better than that obtained for either parameter alone.CONCLUSION:Although it remains unclear whether total serum bilirubin acts as an active player or a bystander, we conclude that the systematic assessment of bilirubin may, alongside lactate levels, provide useful information for clinical decision making regarding carbon monoxide poisoning.

The stability of carbon monoxide in stored blood samples / 法医学杂志

Based on the records of carboxyhemoglobin in blood samples stored for recent years, the stability of carboxyhemoglobin in these samples could be affected by the containers, the storage temperatures, the volumes of air above the blood, the saturation of the initial carboxyhemoglobin and preservatives added in these blood samples, among which the storage temperatures, the volumes of air above the blood and the saturation of the initial carboxyhemoglobin are the major influence factors.

Hematologic changes in acute carbon monoxide intoxication

This study was performed to investigate the hematologic changes and its pathogenesis in acute carbon monoxide (CO) intoxication. Serial complete blood counts (CBC) were obtained in 17 patients with acute CO intoxication five times in two weeks. Peripheral blood smear, bone marrow aspiration and biopsy were obtained in 7 patients within the first week. We analyzed the results of serial CBC's. Levels of hemoglobin and hematocrit rose only initially, probably due to dehydration and hemoconcentration rather than hypoxia. Leukocytosis, mainly neutrophilic, observed during the first few days seemed to be a physiological phenomena due to a stressful situation, such as hypoxia. Levels of platelet increased steadily after a initial decrease. We found no specific findings in bone marrow.