A possible role for the venous-to-arterial CO2 difference in cardiogenic shock: an exploratory study. / Estudio exploratorio del rol de la diferencia venoarterial de dióxido de carbono en el shock cardiogénico.

OBJECTIVES: The venous-to-arterial CO2 partial pressure difference (CO2) is a marker of how adequately capillary blood flow is able to remove CO2 from tissues, but evidence regarding its usefulness in patients with cardiogenic shock (CS) is scarce The main objective of this study was to describe the changes in CO2 in patients with cardiogenic shock during the 48 hours after hospital admission. A secondary objective was to analyze the association between CO2 and in-hospital mortality due to cardiovascular disease (CVD) and cardiogenic shock refractory to treatment. MATERIAL AND METHODS: Prospective observational exploratory study in a single hospital. Patients in cardiogenic shock who were admitted to a cardiology critical care unit were included. We measured CO2 on inclusion and 6, 12, 24, and 48 hours after admission to the unit. Variables were explored with logistic regression analysis and areas under the receiver operating characteristic curves were calculated. RESULTS: A total of 50 patients were included. In-hospital mortality due to CVD was 20%. CO2 peaked initially and decreased gradually over the first 48 hours of care. In-hospital mortality tended to be higher in patients with the highest CO2 values, but the difference was not significant. High CO2 values at 24 hours were associated with refractory cardiogenic shock. The negative predictive value of a CO2 value lower than 6 mmHg at 12 hours was 87% for mortality due to CVD. CONCLUSION: This exploratory study suggests that CO2 could be a helpful additional marker to measure when managing cardiogenic shock. CO2 lower than 6 mmHg between 12 and 24 hours after admission may identify patients at low risk of death due to CVD or refractory cardiogenic shock.

OBJETIVO: La diferencia venoarterial de dióxido de carbono (CO2) representa la adecuación del flujo capilar para eliminar CO2 tisular, sin embargo, su evidencia en pacientes con shock cardiogénico (SC) es escasa. El objetivo primario fue caracterizar la cinética de la diferencia venoarterial de CO2 en pacientes con SC durante las primeras 48 horas de ingreso. El objetivo secundario fue analizar la asociación de la CO2 con la mortalidad intrahospitalaria de causa cardiovascular y el SC refractario. METODO: Estudio exploratorio, observacional, prospectivo y unicéntrico. Se incluyeron pacientes en SC ingresados en una unidad de cuidados críticos cardiológicos. Se determinó la CO2 a la inclusión, a las 6, 12, 24 y 48 horas y se realizó un análisis de regresión logística y curvas de la característica operativa del receptor. RESULTADOS: Se incluyeron 50 pacientes. La mortalidad cardiovascular intrahospitalaria fue del 20%. La cinética de la CO2 mostró un pico inicial y un progresivo descenso durante las primeras 48 horas. Los pacientes con valores más altos de CO2 tuvieron una mayor mortalidad cardiovascular intrahospitalaria, pero esta diferencia no fue significativa. A las 24 horas, valores elevados de CO2 se asociaron significativamente con SC refractario. Un valor inferior a 6 mmHg a las 12 horas mostró un valor predictivo negativo del 87% para mortalidad cardiovascular. CONCLUSIONES: Este estudio exploratorio sugiere la potencial utilidad de la CO2 como biomarcador adicional en el manejo del SC. La CO2 permite identificar pacientes con bajo riesgo de mortalidad cardiovascular y SC refractario cuando sus valores son inferiores a 6 mmHg a las 12-24 horas de evolución.

Estudio exploratorio del rol de la diferencia venoarterial de dióxido de carbono en el shock cardiogénico / A possible role for the venous-to-arterial CO2 difference in cardiogenic shock: an exploratory study

Introducción y objetivos: La diferencia venoarterial de dióxido de carbono (ΔCO2) representa la adecuación del flujo capilar para eliminar CO2 tisular, sin embargo, su evidencia en pacientes con shock cardiogénico (SC) es escasa”. El objetivo primario fue caracterizar la cinética de la diferencia venoarterial de ΔCO2 en pacientes con SC durante las primeras 48 horas de ingreso. El objetivo secundario fue analizar la asociación de la ΔCO2 con la mortalidad intrahospitalaria de causa cardiovascular y el SC refractario. Método: Estudio exploratorio, observacional, prospectivo y unicéntrico. Se incluyeron pacientes en SC ingresados en una unidad de cuidados críticos cardiológicos. Se determinó la ΔCO2 a la inclusión, a las 6, 12, 24 y 48 horas y se realizó un análisis de regresión logística y curvas de la característica operativa del receptor. Resultados: Se incluyeron 50 pacientes. La mortalidad cardiovascular intrahospitalaria fue del 20%. La cinética de la ΔCO2 mostró un pico inicial y un progresivo descenso durante las primeras 48 horas. Los pacientes con valores más altos de ΔCO2 tuvieron una mayor mortalidad cardiovascular intrahospitalaria, pero esta diferencia no fue significativa. A las 24 horas, valores elevados de ΔCO2 se asociaron significativamente con SC refractario. Un valor inferior a 6 mmHg a las 12 horas mostró un valor predictivo negativo del 87% para mortalidad cardiovascular. Conclusiones: Este estudio exploratorio sugiere la potencial utilidad de la ΔCO2 como biomarcador adicional en el manejo del SC. La ΔCO2 permite identificar pacientes con bajo riesgo de mortalidad cardiovascular y SC refractario cuando sus valores son inferiores a 6 mmHg a las 12-24 horas de evolución. (AU)

Background and objectives: The venous-to-arterial CO2 partial pressure difference ('CO2) is a marker of how adequately capillary blood flow is able to remove CO2 from tissues, but evidence regarding its usefulness in patients with cardiogenic shock (CS) is scarce The main objective of this study was to describe the changes in 'CO2 in patients with cardiogenic shock during the 48 hours after hospital admission. A secondary objective was to analyze the association between 'CO2 and in-hospital mortality due to cardiovascular disease (CVD) and cardiogenic shock refractory to treatment. Methods: Prospective observational exploratory study in a single hospital. Patients in cardiogenic shock who were admitted to a cardiology critical care unit were included. We measured 'CO2 on inclusion and 6, 12, 24, and 48 hours after admission to the unit. Variables were explored with logistic regression analysis and areas under the receiver operating characteristic curves were calculated. Results: A total of 50 patients were included. In-hospital mortality due to CVD was 20%. 'CO2 peaked initially and decreased gradually over the first 48 hours of care. In-hospital mortality tended to be higher in patients with the highest 'CO2 values, but the difference was not significant. High 'CO2 values at 24 hours were associated with refractory cardiogenic shock. The negative predictive value of a 'CO2 value lower than 6 mmHg at 12 hours was 87% for mortality due to CVD. Conclusions: This exploratory study suggests that 'CO2 could be a helpful additional marker to measure when managing cardiogenic shock. 'CO2 lower than 6 mmHg between 12 and 24 hours after admission may identify patients at low risk of death due to CVD or refractory cardiogenic shock. (AU)

Capnografia volumétrica para monitoração respiratória de pacientes submetidos a colonoscopia diagnóstica com insuflação de ar comprimido e gás carbônico / Volumetric capnography for respiratory monitoring of patients during routine colonoscopy with room-air and carbon dioxide insufflation

ABSTRACT Background: Capnography and carbon dioxide (CO2) insufflation during gastrointestinal endoscopy under sedation are associated with safety and comfort improvements, respectively. Capnography can provide early detection of apnea and hypoxemia, whereas CO2 insufflation causes lower periprocedural discomfort. This is the first study to report the application of volumetric capnography in colonoscopy. Objective: This study aimed to evaluate the use of volumetric capnography with room air (RA) and CO2 insufflation during routine colonoscopy. Methods: In this prospective cohort study, 101 patients who underwent routine colonoscopy under sedation with volumetric capnography monitoring were included. Insufflation with RA was used to distend the intestinal lumen in group 1 (n=51), while group 2 (n=50) used CO2 insufflation. The primary endpoints were episodes of hypoxia, alveolar hypoventilation, and end-tidal CO2 (EtCO2). The secondary endpoints were tidal volume per minute, consumption of sedation medications, and post-procedure pain using the Gloucester modified pain scale. Results: The number of episodes of hypoxia (SpO2<90%) was similar between the groups: four episodes in Group 1 and two episodes in Group 2. The duration of hypoxia was significantly longer in group 2 (P=0.02). Hypoalveolar ventilation (EtCO2) occurred more frequently in Group 2 than in Group 1 (27 vs 18 episodes, P=0.05). Regarding EtCO2, Group 2 showed higher values in cecal evaluation (28.94±4.68 mmHg vs 26.65±6.12 mmHg, P=0.04). Regarding tidal volume per minute, Group 2 had significantly lower values at the cecal interval compared to Group 1 (2027.53±2818.89 vs 970.88±1840.25 L/min, P=0.009). No episodes of hypercapnia (EtCO2 > 60 mmHg) occurred during the study. There was no difference in the consumption of sedation medications between the groups. Immediately after colonoscopy, Group 2 reported significantly less pain than Group 1 (P=0.05). Conclusion: In our study, volumetric capnography during colonoscopy was feasible and effective for monitoring ventilatory parameters and detecting respiratory complications. CO2 insufflation was safe and associated with less pain immediately after colonoscopy.

RESUMO Contexto: A capnografia e a insuflação de gás carbônico (CO2) durante endoscopia digestiva sob sedação são associados à maior segurança e conforto do paciente, respectivamente. A capnografia pode detectar precocemente a apneia e hipoxemia, enquanto a insuflação de CO2 causa menor desconforto periprocedimento. Relatos da aplicação da capnografia volumétrica em colonoscopias são escassos. Objetivo: Avaliar o uso de capnograifa volumétrica durante colonoscopia diagnóstica com insuflação de ar comprimido e CO2. Métodos: Em estudo prospectivo de coorte, foram incluídos um total de 101 pacientes submetidos a colonoscopia diagnóstica sob sedação com monitoração respiratória por meio de capnografia volumétrica. Insuflação com ar comprimido foi usado para distender o lúmen intestinal no Grupo 1 (n=51), enquanto o Grupo 2 (n=50) utilizou CO2 para insuflação. Objetivos primários foram avaliar episódios de hipóxia, hipoventilação alveolar e CO2 expirado (EtCO2). Objetivos secundários foram avaliar o volume alveolar por minuto, consumo de sedativos e a dor pós-colonoscopia por meio da Escala de Dor Modificada de Gloucester. Resultados: O número de episódios de hipóxia (SpO2 <90%) foi semelhante entre os grupos: quatro episódios no Grupo 1 e dois episódios no Grupo 2. A duração da hipóxia foi significativamente maior no Grupo 2 (P=0,02). A hipoventilação alveolar (EtCO2 ≥25% do valor basal) ocorreu mais frequentemente no Grupo 2 quando comparado ao Grupo 1 (27 vs 18 episódios, P=0,05). Em relação ao EtCO2, o Grupo 2 apresentou valores maiores no momento de aferição cecal (28.94±4.68 vs 26.65±6.12 mmHg, P=0,04). Quanto ao volume alveolar por minuto, o Grupo 2 apresentou valores significativamente menores no momento de aferição cecal quando comparado ao Grupo 1 (2027.53±2818.89 vs 970.88±1840.25 L/min, P=0,009). Não houve ocorrência de hipercapnia durante o estudo (EtCO2 >60 mmHg). Não houve diferença em relação ao consumo de sedativos entre os dois grupos. Imediatamente após a colonoscopia, o Grupo 2 apresentou significativamente menos dor que o Grupo 1 (P=0,05). Conclusão: Em nosso estudo, a capnografia volumétrica durante colonoscopia foi factível e eficaz para monitorar parâmetros ventilatórios e detectar complicações respiratórias, e a insuflação com CO2 foi segura e associada a menor dor imediatamente pós-colonoscopia.

Comparação da proporção entre pressão venosa central menos arterial de dióxido de carbono e conteúdo de oxigênio arterial menos venoso central e níveis de lactato como preditores de mortalidade em pacientes críticos: uma revisão sistemática e metanálise / Comparison of central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio and lactate levels as predictors of mortality in critically ill patients: a systematic review and meta-analysis

RESUMO Objetivo: A proporção entre pressão venosa central menos arterial de dióxido de carbono e conteúdo de oxigênio arterial menos venoso central (Pcv-aCO2/Ca-cvO2) é frequentemente usada como substituta para a oxigenação tecidual. O objetivo deste estudo foi identificar e sintetizar a literatura e a qualidade das evidências que suportam a Pcv-aCO2/Ca-cvO2 como um preditor de mortalidade em comparação com o lactato em pacientes críticos. Métodos: Pesquisamos vários bancos de dados procurando estudos que tivessem medido a Pcv-aCO2/Ca-cvO2 em pacientes críticos. Pesquisadores independentes realizaram a triagem dos artigos e a extração de dados. Uma metanálise de efeitos aleatórios foi realizada. Diferenças médias padronizadas agrupadas foram usadas para comparar a capacidade prognóstica da Pcv-aCO2/Ca-cvO2 e do lactato. Resultados: Inicialmente, obtivemos 172 estudos; 17 foram incluídos para descrição qualitativa, e dez foram incluídos para síntese quantitativa. A média de Pcv-aCO2/Ca-cvO2 foi maior nos não sobreviventes do que nos sobreviventes (diferença média padronizada agrupada de 0,75; IC95% 0,34 - 1,17; I2 = 83%), assim como os níveis de lactato (diferença média padronizada agrupada = 0,94; IC95% 0,34 - 1,54; I2 = 92%). Ambos os testes foram preditores estatisticamente significativos de mortalidade, embora com sobreposição de IC95% entre eles. Conclusão: Evidências de qualidade moderada mostraram pouca ou nenhuma diferença na capacidade da Pcv-aCO2/Ca-cvO2, em comparação com o lactato, em predizer mortalidade. No entanto, nossas conclusões são limitadas pela considerável heterogeneidade entre os estudos. Registro no PROSPERO:CRD42019130387

ABSTRACT Objective: The central venousarterial carbon dioxide pressure to arterial-central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) is frequently used as a surrogate for tissue oxygenation. We aimed to identify and synthesize literature and quality of evidence supporting Pcv-aCO2/Ca-cvO2 as a predictor of mortality in critically ill patients compared with lactate. Methods: We searched several databases for studies measuring Pcv-aCO2/Ca-cvO2 in critically ill patients. Independent investigators performed the article screening and data extraction. A random-effects metaanalysis was performed. Pooled standardized mean differences (SMD) were used to compare the prognostic ability of Pcv-aCO2/Ca-cvO2 and lactate. Results: We initially retrieved 172 studies; 17 were included for qualitative description, and 10 were included for quantitative synthesis. The mean Pcv-aCO2/Ca-cvO2 was higher in nonsurvivors than in survivors (pooled SMD = 0.75; 95%CI 0.34 - 1.17; I2 = 83%), as was the case with lactate levels (pooled SMD = 0.94; 95%CI 0.34 - 1.54; I2 = 92%). Both tests were statistically significant predictors of mortality, albeit with overlapping 95%CIs between them. Conclusion: Moderate-quality evidence showed little or no difference in the ability of Pcv-aCO2/Ca-cvO2, compared with lactate, to predict mortality. Nevertheless, our conclusions are limited by the considerable heterogeneity among the studies. PROSPERO registration:CRD42019130387

¿Cuándo debería y cuándo no debería utilizarse oxígeno en las enfermedades neuromusculares? / When should and when should not use oxygen in neuromuscular diseases?

Resumen A pesar de las referencias que advierten sobre los efectos adversos de la utilización de O2 suplementario sin asistencia ventilatoria en pacientes con enfermedades neuromusculares (ENM), aún hoy continúan ingresando pacientes en unidades de cuidados intensivos con hipercapnia grave y narcosis por CO2. Parecería que el problema es redescubierto según pasan los años y las generaciones. Muchos pacientes y su red de cuidadores formales e informales no son conscientes de este riesgo que puede llevar a un empeoramiento significativo de los síntomas, eventos agudos, ingresos hospitalarios y, en algunos casos, causar la muerte. Este artículo está centrado en los riesgos de la administración de O2, así como en sus indicaciones puntuales en personas con ENM. El problema central es que la administración de O2 puede quitar el impulso hipóxico para ventilar, aunque otros mecanismos podrían estar involucrados. El retiro completo de la oxigenoterapia sin apoyo de asistencia ventilatoria, es un error aún mayor. Es posible administrar O2 y controlar el CO2 de forma segura. Nunca se debe administrar O2 sin monitorear constantemente el nivel de CO2. La ventilación no invasiva binivelada (BiPAP) mediante interfaz nasal, bucal o boquilla, es la principal medida para revertir la hipoventilación y lograr el descenso de la PaCO2. Las indicaciones de oxigenoterapia en personas con ENM han sido consensuadas y están reservadas a situaciones específicas. Para mejorar la atención de aquellos enfermos con ENM y evitar intervenciones iatrogénicas, se requiere educación al equipo de salud y contención en el entorno del paciente.

Abstract Although the references warn about the adverse effects of adding O2 without ventilatory assistance in patients with neuromuscular diseases (NMD), patients are still to be admitted to intensive care units with severe hypercapnia and CO2 narcosis. It seems that the problem is rediscovered as the years and generations go by. Unfortunately, many patients and their network of formal and informal caregivers are unaware of this risk, leading to significant worsening of symptoms, acute events, hospital admissions, and, in some cases, cause death. This article focuses on the dangers of O2 administration as well as its precise indications in people with NMD. The central problem is that the administration of O2 can remove the hypoxic impulse to ventilate, however, other mechanisms could be involved, but. The complete withdrawal of oxygen therapy is an even greater mistake if it is not supported by ventilatory assistance. It is possible to supply O2 and control CO2 safely. Oxygen should never be administered without constantly monitoring the CO2 level. Bi-level non-invasive ventilation (BiPAP) through a buccal, nasal interface or mouthpiece is the primary measure to reverse hypoventilation and achieve a decrease in PaCO2. The indications for oxygen therapy in people with NMD have been agreed upon and are reserved for specific situations. To improve the care of those with NMD and avoid iatrogenic interventions, education of the health team and support in the patient's environment is required.

Determinantes de la salud ambiental en el Perú: curva de Kuznets 1990-2015 / Determinants of environmental health in Peru: Kuznets curve 1990-2015

El ambiente es el lugar donde vive, trabaja y se desarrolla el hombre, compuesto básicamente por dos sistemas interrelacionados e independientes: por una parte, es el hombre conviviendo en una sociedad con características muy diferentes, y por el otro lado, los elementos de la naturaleza siendo transformados por los hombres donde viven inmersos. En ese sentido, la degradación y contaminación ambiental, tienen efectos notables en la vidad de los seres humanos, siendo responsable de la muerte de cientos de millones de personas que sufren de enfermedades respiratorias asociadas con la contaminación externa e interior del aire. En ese sentido, ya a partir de las últimas décadas, las emisiones de dióxido de carbono han alcanzado cifras record superando las 10 gigatoneladas. Este incremento está asociado al sector energético (47%), la industria (30%) y el transporte (11%) principalmente, lo que ha logrado un calentamiento global progresivo de la superficie terrestre con las consecuencias típicas asociadas al derretimiento de los glaciares, cambios en los ciclos hidrológicos, falta de alimentos, aumento de los fenómenos meteorológicos, migraciones descontroladas, enfermedades y pandemias. De este modo, surge la economía ambiental, una disciplina que intenta dar repuestas integrales entre ambos tópicos, medio ambiente y economía, donde diversas teorías tratan de explicar los fenómenos observados. El concepto de las Curvas de Kuznets Ambientales (CKA), señala una relación dinámica entre el PIB y la calidad del medio ambiente. El objetivo del artículo ha sido determinar si en el Perú, durante el periodo 1990-2015, ha habido una relación en forma de U invertida entre la producción interna y la contaminación del aire. La investigación prueba que, en el Perú, durante el periodo 1990-2015, no ha habido una relación en forma de U invertida entre la producción interna y la contaminación del aire, sino que la producción interna ha tenido un impacto positivo y lineal sobre el dióxido de carbono y el óxido de nitrógeno(AU)

The environment is the place where man lives, works and develops, basically composed of two interrelated and independent systems: on the one hand, it is man living together in a society with very different characteristics, and on the other hand, the elements of the nature being transformed by men where they live immersed. In this sense, environmental degradation and pollution have notable effects on the lives of human beings, being responsible for the death of hundreds of millions of people who suffer from respiratory diseases associated with external and internal air pollution. In this sense, already in recent decades, carbon dioxide emissions have reached record figures, exceeding 10 gigatons. This increase is mainly associated with the energy sector (47%), industry (30%) and transport (11%), which has achieved a progressive global warming of the earth's surface with the typical consequences associated with the melting of glaciers, changes in hydrological cycles, lack of food, increased weather events, uncontrolled migrations, diseases and pandemics. In this way, environmental economics arises, a discipline that tries to provide comprehensive answers between both topics, environment and economy, where various theories try to explain the observed phenomena. The concept of the Environmental Kuznets Curves (EKC), indicates a dynamic relationship between GDP and the quality of the environment. The objective of the article has been to determine if in Peru, during the period 1990-2015, there has been an inverted U-shaped relationship between internal production and air pollution. The research proves that, in Peru, during the period 1990-2015, there has not been an inverted U-shaped relationship between domestic production and air pollution, but rather that domestic production has had a positive and linear impact on air pollution. carbon dioxide and nitrogen oxide(AU)

Fisiología respiratoria: transporte de gases en sangre / Respiratory physiology: transport of oxygen and carbon dioxide in the blood

La sangre normalmente transporta pequeñas cantidades de oxígeno (O2) disuelto en el plasma y altas cantidades combinadas en forma química con la hemoglobina. La presión parcial depende solo del oxígeno disuelto físicamente, lo que determina cuánto oxígeno se combinará con hemoglobina. La curva de disociación de la hemoglobina describe la reversibilidad de la reacción entre oxígeno y hemoglobina. Los factores habituales que aumentan o disminuyen la afinidad de la hemoglobina por el oxígeno son el pH, presión parcial de CO2, temperatura y 2,3 difosfoglicerato. La sangre también transporta grandes cantidades en forma de bicarbonato y bajas cantidades de CO2 disuelto en plasma y combinado con proteínas como compuestos carbamino. La desoxihemoglobina favorece la formación de compuestos carbamínicos y promueve el transporte del CO2 como bicarbonato uniéndose al hidrógeno proveniente de la disociación del ácido carbónico. A continuación se describe en forma detallada los mecanismos fisiológicos del transporte de gases en sangre.

Blood normally carries small amounts of oxygen dissolved in plasma and large amounts chemically combined with hemoglobin. Partial pressure of oxygen depends only on physically dissolved oxygen which determines how much oxygen will combine with hemoglobin. The oxygen-hemoglobin dissociation curve (or oxyhemoglobin dissociation curve) describes the reversibility of the reaction between oxygen and hemoglobin. The usual factors that increase or decrease the affinity of hemoglobin for oxygen are pH, CO2 partial pressure, temperature, and 2,3 diphosphoglycerate. Blood also carries large amounts of CO2 as bicarbonate and low amounts dissolved in plasma and combined with proteins as carbamino compounds. Deoxyhemoglobin favors the formation of carbamino compounds and promotes the transport of CO2 as bicarbonate by joining the hydrogen from the dissociation of carbonic acid. The physiological mechanisms of gas transport in blood are described in detail below.

Fisiología respiratoria: difusión de gases / Gas diffusion

El principal objetivo del sistema respiratorio es permitir un adecuado aporte de oxígeno y remoción del dióxido de carbono. Para esto, debe ocurrir una adecuada difusión de gases en la membrana alvéolo-capilar, proceso pasivo en el que el oxígeno se mueve hacia el capilar y el dióxido de carbono hacia el alvéolo. La ley de Fick establece los determinantes de la difusión, los que están dados por propiedades de la membrana alvéolo-capilar y de los gases. Las características únicas de la membrana alvéolo-capilar favorecen la difusión de gases, pero es el gradiente de presión parcial de los gases el principal determinante. El oxígeno pasa fácilmente por la membrana alvéolo-capilar y se une rápidamente a la hemoglobina, saturándola, cuando se iguala la presión parcial de oxígeno alveolar y la capilar se detiene la difusión de este gas; por lo que la difusión de oxígeno en reposo está limitada por perfusión. El dióxido de carbono difunde 20 veces más rápido que el oxígeno en la membrana alvéolo-capilar, y aunque su gradiente de presión sea menor, el equilibrio se logra aproximadamente en el mismo tiempo. La difusión del oxígeno es más lenta que la del dióxido de carbono debido a su menor solubilidad. En condiciones patológicas tanto el oxígeno como el dióxido de carbono pueden ser limitados por difusión. Para medir la capacidad de difusión la técnica más utilizada es la capacidad de difusión de monóxido de carbono, ya que este gas solo está limitado por difusión.

The main objective of the respiratory system is allowing an adequate supply of oxygen and the removal of carbon dioxide from the tissues. To achieve this, an adequate diffusion of gases must occur in the alveolus-capillary membrane, which is a passive process in which oxygen moves towards the capillary and carbon dioxide towards the alveolus. Fick's law establishes the determinants of diffusion, which are given by properties of the alveolar-capillary membrane and properties of gases. The unique characteristics of the capillary-alveolar membrane favor the diffusion of gases, but it is the partial pressure gradient of the gases the main determinant. Oxygen passes easily through the alveolar-capillary membrane and rapidly binds to hemoglobin, saturating it. When the partial pressure of alveolar oxygen is matched, the diffusion of this gas stops; therefore, the diffusion of oxygen is limited by perfusion. Carbon dioxide diffuses 20 times faster than oxygen in the capillary-alveolar membrane, and although its pressure gradient is less than oxygen, equilibrium is achieved in approximately the same time. The diffusion of oxygen is slower than that of carbon dioxide due to its lower solubility. Under pathological conditions both oxygen and carbon dioxide can be diffusion-limited. To measure the diffusion capacity, the most used technique is the carbon monoxide diffusion capacity, since this gas is only limited by diffusion.

Initial in vitro plant establishment of seeds and nodal segments from bromeliad Acanthostachys strobilacea (Schult. & Schult.f.) Klotzsch differs in respiratory rates and shoot formation / Estabelecimento in vitro inicial de plantas de sementes e segmentos nodais da bromélia Acanthostachys strobilacea (Schult. & Schult.f.) Klotzsch difere em taxas respiratórias e formação de brotos

We aimed to investigate the morphological and respiratory differences during in vitro shoot formation from seeds and nodal segments (NS) of Acanthostachys strobilacea (Schult. & Schult.f.) Klotzsch, due to differences in plants obtained by micropropagation. During 35 days of culture, seeds resulted in full plants 14 days earlier than NS, with longer leaves and more roots. Nevertheless, NS plantlets exhibited shoot multiplication. Peaks in O2 consumption and CO2 release were detected at 7 and 14 days for NS and seeds, respectively, suggesting that initial growth has a high energetic requirement. However, the respiration peak was higher in NS than in seeds, possibly due to high energy consumption required for multiple bud breaks. After peaking, respiration decreased, reaching similar values between propagules by 35 days, indicative of an ongoing increase in photosynthesis in both seed and NS plants, possibly due to shoot growth. In conclusion, the development process of NS plants may affect the energy and respiratory demand differently than in seedlings.

Buscou-se investigar as diferenças morfológicas e respiratórias durante a formação in vitro de brotos a partir de sementes e segmentos nodais (NS) de Acanthostachys strobilacea (Schult. & Schult.f.) Klotzsch, devido às diferenças entre as plantas obtidas pela micropropagação. Durante 35 dias de cultura, as sementes resultaram em plantas completas 14 dias antes do NS, com folhas mais longas e mais raízes. No entanto, as plantas NS exibiram multiplicação de brotos. Picos no consumo de O2 e liberação de CO2 foram detectados aos 7 e 14 dias para NS e sementes, respectivamente, sugerindo que o crescimento inicial tem alta demanda energética. No entanto, o pico de respiração foi maior em NS do que em sementes, possivelmente devido ao alto consumo de energia necessário para as múltiplas quebras de gemas. Após o pico, a respiração diminuiu, atingindo valores semelhantes entre os propágulos aos 35 dias, indicativo de um aumento contínuo da fotossíntese em plantas de sementes e NS, possivelmente devido ao crescimento de brotos. Em conclusão, o processo de desenvolvimento das plantas de NS pode afetar a demanda energética e respiratória de forma diferente daquelas de sementes.

Hemodynamic monitoring with two blood gases: "a tool that does not go out of style" / Monitoreo hemodinámico con dos gasometrías: "Una herramienta que no pasa de moda"

Abstract Hemodynamic monitoring of a critically ill patient is an indispensable tool both inside and outside intensive care; we currently have invasive, minimally invasive and non-invasive devices; however, no device has been shown to have a positive impact on the patient's evolution; arterial and venous blood gases provide information on the patient's actual microcirculatory and metabolic status and may be a hemodynamic monitoring tool. We aimed to carry out a non-systematic review of the literature of hemodynamic monitoring carried out through the variables obtained in arterial and venous blood gases. A non-systematic review of the literature was performed in the PubMed, OvidSP and ScienceDirect databases with selection of articles from 2000 to 2019. It was found that there are variables obtained in arterial and venous blood gases such as central venous oxygen saturation (SvcO2), venous-to-arterial carbon dioxide pressure (Δpv-aCO2), venous-to-arterial carbon dioxide pressure/arteriovenous oxygen content difference (Δpv-aCO2/ΔCavO2) that are related to cellular oxygenation, cardiac output (CO), microcirculatory veno-arterial flow and anaerobic metabolism and allow to assess tissue perfusion status. In conclusion, the variables obtained by arterial and venous blood gases allow for non-invasive, accessible and affordable hemodynamic monitoring that can guide medical decision-making in critically ill patients.

Resumen El monitoreo hemodinámico de un paciente en estado crítico es una herramienta indispensable tanto dentro como fuera de la terapia intensiva; actualmente se cuenta con dispositivos invasivos, mínimamente invasivos y no invasivos; sin embargo, ningún dispositivo ha demostrado tener impacto positivo en la evolución del paciente; la gasometría arterial y venosa proporcionan información del estado microcirculatorio y metabólico real del paciente pudiendo ser una herramienta de monitoreo hemodinámico. El objetivo de esta revisión fue realizar una revisión no sistemática de la literatura del monitoreo hemodinámico realizado mediante las variables obtenidas en la gasometría arterial y venosa. Se estudiaron las bases de datos de PubMed, OvidSP y ScienceDirect con selección de artículos del 2000 al 2019. Se encontró que hay variables obtenidas en la gasometría arterial y venosa como la saturación venosa central de oxígeno (SvcO2), la diferencia de presión venoarterial de dióxido de carbono (Δpv-aCO2), la diferencia de presión venoarterial de dióxido de carbono/diferencia del contenido arteriovenoso de oxígeno (Δpv-aCO2/ΔCa-vO2) que están relacionadas con la oxigenación celular, con el gasto cardiaco (GC), con el flujo venoarterial microcirculatorio y con el metabolismo anaerobio que permiten realizar una valoración del estado de perfusión tisular. En conclusión, las variables obtenidas por gasometría arterial y venosa permiten realizar un monitoreo hemodinámico no invasivo, accesible y asequible que pueden guiar la toma de decisiones médicas en el paciente en estado crítico.

Reduction in global habitat loss from fossil-fuel-dependent increases in cropland productivity.

Terrestrial biodiversity loss and climate change, driven mainly by loss of habitat to agriculture and fossil fuel (FF) use, respectively, are considered among the world's greatest environmental threats. However, FF-dependent technologies are currently essential for manufacturing synthetic nitrogen fertilizers (SNFs) and synthetic pesticides (SPs) critical to increasing agricultural productivity, which reduces habitat loss. Fossil fuel use increases CO2 levels, further enhancing agricultural productivity. Based on estimates of global increases in yields from SNFs, SPs, and atmospheric CO2 fertilization, I estimated that FF-dependent technologies are responsible for at least 62.5% of current global food production (GFP) from cropland. Thus, if FF use is eschewed in the future, maintaining current GFP means croplands would have to increase from 12.2% of global land area (GLA) excluding Antarctica to 32.7%. The additional 20.4% of GLA needed exceeds habitat lost currently to cropland (12.2% of GLA) and cumulative conservation areas globally (14.6% of GLA). Thus, although eliminating FF use could reduce climate change, its unintended consequences may be to significantly exacerbate biodiversity loss and indirectly increase food costs, reducing food security which, moreover, disproportionately affects the poor. Although it may be possible to replace SNFs and SPs with FF-free technologies, such substitutes have not yet been demonstrated to be sufficiently economical or efficient. In the interim, meeting global food demand and keeping food prices affordable would increase habitat conversion and food prices. These trade-offs should be considered in analyses of climate change policies.

Reducción de la Pérdida Mundial de Hábitat a Partir de Incrementos Dependientes de Combustibles Fósiles en la Productividad de los Terrenos de Cultivo Resumen La pérdida de la biodiversidad terrestre y el cambio climático, causados principalmente por la pérdida del hábitat debido a la agricultura y al uso de combustibles fósiles (CF) respectivamente, están consideradas entre las más grandes amenazas ambientales a nivel mundial. Sin embargo, las tecnologías dependientes de los CF son actualmente de mucha importancia para la manufactura de fertilizantes sintéticos de nitrógeno (FSN) y de pesticidas sintéticos (PS) fundamentales para el incremento de la productividad agrícola, lo cual reduce la pérdida del hábitat. El uso de los CF incrementa los niveles de CO2 , mejorando todavía más la productividad agrícola. Con base en los estimados de los incrementos mundiales de producción de FSN, PS y la fertilización por CO2 atmosférico estimé que las tecnologías dependientes de los CF son las responsables de al menos el 62.5% de la producción mundial de alimentos (PMA) en las tierras de cultivo. Por esto, si en el futuro se evita el uso de los FF, para mantener la PMA actual los terrenos de cultivo tendrían que incrementar de 12.2% del área global de suelo (AGS) (excluyendo a la Antártida) a 32.7%. El 20.4% adicional del AGS necesaria excede a los hábitats perdidos hasta ahora por terrenos de cultivo (12.2% del AGS) y a las áreas acumuladas de conservación (14.6% del AGS) en todo el mundo. Por lo tanto, mientras que la eliminación de los CF podría reducir el avance del cambio climático, las consecuencias imprevistas de esto podrían exacerbar significativamente la pérdida de la biodiversidad e indirectamente incrementar el costo de los alimentos, reduciendo así la seguridad alimentaria. Aunque puede ser posible reemplazar los FSN y los PS con tecnologías libres de CF, no se ha demostrado que dichos sustitutos sean suficientemente económicos o eficientes. Mientras tanto, cumplir la demanda mundial de alimentos y mantener costeables los precios alimentarios incrementa la conversión de los hábitats. Estas compensaciones deberían ser consideradas en los análisis de las políticas para el cambio climático.

Efecto de atmósferas modificadas con CO 2 sobre la germinación de banco de semillas de malezas / Effect of atmospheres modified with CO 2 on the germination of weed seed bank

RESUMEN Aumentos en la concentración de dióxido de carbono -CO2- atmosférico, pueden generar modificaciones sobre la composición florística, biología y ecología de malezas, lo que puede implicar modificaciones en el manejo de las mismas. Con el objetivo de reconocer el efecto del CO2 sobre la germinación de un banco de semillas de malezas, proveniente de un suelo de uso agrícola, se ejecutó un diseño experimental completamente al azar, el cual, se planteó como un arreglo factorial con muestras de suelo, provenientes de 2 profundidades, 5 dosis de CO2, 4 réplicas por tratamiento y 3 medidas repetidas en el tiempo. Evaluándose el efecto de 5 concentraciones atmosféricas de CO2 -400, 500, 700, 800, 900ppm-, sobre la germinación del banco de semillas. Para esto, se tomaron materos con muestras de suelo, que fueron llevados a cámaras confinadas, en donde se adicionó CO2, hasta el valor de referencia. Allí, se mantuvieron en condiciones de germinación durante todo el experimento. Los resultados indican diferencias significativas en los tratamientos en los que se adicionó CO2, los análisis fitosociológicos muestran que el tratamiento de 900ppm de CO2 presentó la mayor riqueza y diversidad, según índice de Shannon (H´) y el tratamiento de 800ppm presentó la mayor cantidad de individuos. Lolium temuletum L. fue la especie dominante del banco de semillas, evidenciándose una respuesta positiva de la especie en relación al enriquecimiento atmosférico. Los resultados indican que ambientes enriquecidos de CO2 inducen una variación en la diversidad poblacional del banco de semillas evaluado.

ABSTRACT Increases in atmospheric carbon dioxide concentration - CO2-, can be able generate modifications on the floristic composition, biology and ecology of weeds, what can to imply modifications in their management. With the aim of recognizing the effect of CO2-modified atmospheres on germination of weed seed bank from an agricultural soil, a completely randomized experimental design was executed, which was proposed as a factorial arrangement with soil samples from 2 depths, 5 doses of CO2, 4 replicates per treatment and 3 measures repeated over time. Evaluating the effect of 5 atmospheric concentrations of CO2-400,500,700,800,900ppm-, on the germination of the seed bank. For this, pot was taken with soil samples, which were taken to confined chambers where CO2 was added up to the reference value. There they were kept under germination conditions throughout the experiment. The results indicate significant differences in the treatments in which CO2 was added, the phytosociological analyzes show that the treatment of 900ppm of CO2 presented the greatest richness and diversity according to the Shannon index (H´) and the 800ppm treatment presented the largest number of individuals. Lolium temuletum L. was the dominant species in the seed bank, showing a positive response of the species in relation to atmospheric enrichment. The results indicate CO2 enriched environments induce a variation in the population diversity of the evaluated seed bank.

Relación entre el índice gradiente dióxido de carbono/gradiente arteriovenoso de oxígeno y lactato en el choque séptico por neumonía / Relationship between carbon dioxide gradient/arteriovenous oxygen gradient index and lactate in septic shock secondary to pneumonia

RESUMEN Objetivo Determinar la relación del índice gradiente de dióxido de carbono/gradiente arteriovenoso de oxígeno y lactato en pacientes con neumonía complicada y choque séptico en áreas críticas del Hospital III EsSalud Chimbote durante el periodo 2018 y 2019. Materiales y métodos Estudio de tipo cuantitativo, observacional, correlacional y longitudinal de tendencias. La unidad de análisis está constituida por los pacientes con neumonía complicada por choque séptico que presentan lecturas de índice de gradiente dióxido de carbono / gradiente arteriovenoso de oxígeno y lecturas de lactato. Resultados Se incluyeron 90 pacientes con neumonía complicada por choque séptico. El presente trabajo de investigación demuestra una fuerte relación entre el índice de gradiente de gases y el lactato sérico: al inicio, 3 horas, 6 horas y a las 12 horas, de iniciado y monitorizado estos pacientes. Conclusiones El índice del gradiente de dióxido de carbono/gradiente concentración arterio venoso de oxígeno > 1.4, se relaciona con el lactato sérico, en pacientes con shock séptico por neumonía.

ABSTRACT Objective To determine the relationship between carbon dioxide gradient/arteriovenous oxygen gradient index and lactate in patients with pneumonia complicated by septic shock in areas delivering care for critically ill or injured patients of the Hospital III EsSalud Chimbote between 2018 and 2019. Materials and methods A quantitative, observational, correlational, longitudinal trend study. The study population consisted of patients with pneumonia complicated by septic shock who had carbon dioxide gradient/arteriovenous oxygen gradient index and lactate readings. Results Ninety (90) patients with pneumonia complicated by septic shock participated in the research. The present study showed a robust relationship between gas gradient index and serum lactate when monitoring patients at baseline, 3 hours, 6 hours and 12 hours. Conclusions There is a relationship between carbon dioxide gradient/arteriovenous oxygen gradient index (> 1.4) and serum lactate levels in patients with septic shock secondary to pneumonia.

Depuración extracorpórea de dióxido de carbono con reemplazo renal continuo. Descripción de un caso y revisión de la literatura / Extracorporeal carbon dioxide removal with continuous renal replacement therapy. Case description and literature review

RESUMEN En los últimos años, y debido en parte a los avances tecnológicos, ha resurgido el uso de los sistemas de depuración extracorpórea de dióxido de carbono de manera pareja al uso de la oxigenación con membrana extracorpórea. No obstante, faltan estudios para establecer sus indicaciones y el nivel de evidencia para su uso. Estos sistemas permiten eliminar el dióxido de carbono de manera eficaz en pacientes con insuficiencia respiratoria hipercápnica con catéteres de pequeño calibre, habitualmente de doble luz y con pequeña superficie de membrana depuradora. En la actualidad disponemos de varios tipos de sistemas, con distinta versatilidad y tamaño de membrana. Los sistemas veno-venosos con bomba producen menos complicaciones que los arterio-venosos. Ambos precisan anticoagulación sistémica. El soporte "pulmón-riñón" mediante la combinación de un sistema depurador con un hemofiltro permitiría al mismo tiempo eliminar dióxido de carbono y realizar depuración extrarrenal continua. Describimos nuestra experiencia inicial con un sistema combinado de depuración extracorpórea de dióxido de carbono-depuración extrarrenal continua en un paciente con trasplante de pulmón, insuficiencia respiratoria hipercápnica, barotrauma y fallo renal agudo asociado. Se describen los aspectos técnicos más importantes, la efectividad del sistema para la eliminación de dióxido de carbono y se realiza una revisión de la literatura.

ABSTRACT In recent years and due, in part, to technological advances, the use of extracorporeal carbon dioxide removal systems paired with the use of extracorporeal membrane oxygenation has resurfaced. However, studies are lacking that establish its indications and evidence to support its use. These systems efficiently eliminate carbon dioxide in patients with hypercapnic respiratory failure using small-bore cannula, usually double-lumen cannula with a small membrane lung surface area. Currently, we have several systems with different types of membranes and sizes. Pump-driven veno-venous systems generate fewer complications than do arteriovenous systems. Both require systemic anticoagulation. The "lung-kidney" support system, by combining a removal system with hemofiltration, simultaneously eliminates carbon dioxide and performs continuous extrarenal replacement. We describe our initial experience with a combined system for extracorporeal carbon dioxide removal-continuous extrarenal replacement in a lung transplant patients with hypercapnic respiratory failure, barotrauma and associated acute renal failure. The most important technical aspects, the effectiveness of the system for the elimination of carbon dioxide and a review of the literature are described.

Proporção entre pressão venosa central menos arterial de dióxido de carbono e conteúdo arterial menos venoso central de oxigênio como indicador de oxigenação tissular: uma revisão narrativa / Central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio as an indicator of tissue oxygenation: a narrative review

RESUMO A proporção entre pressão venosa central menos arterial de dióxido de carbono e conteúdo de oxigênio arterial menos venoso central (Pcv-aCO2/Ca-cvO2) foi proposta como marcador substituto para quociente respiratório e indicador de oxigenação tissular. Alguns pequenos estudos observacionais identificaram que Pcv-aCO2/Ca-cvO2 acima de 1,4 se associa com hiperlactatemia, dependência de suprimento de oxigênio e maior mortalidade. Mais ainda, a Pcv-aCO2/Ca-cvO2 foi incorporada a algoritmos para avaliação da oxigenação tissular e ressuscitação. Contudo, a evidência para estas recomendações é bastante limitada e de baixa qualidade. O objetivo desta revisão narrativa foi analisar as bases metodológicas, os fundamentos fisiopatológicos e a evidência experimental e clínica para dar suporte à utilização da Pcv-aCO2/Ca-cvO2 como marcador substituto para quociente respiratório. De um ponto de vista fisiopatológico, o aumento do quociente respiratório secundariamente a reduções críticas no transporte de oxigênio é um evento dramático e com risco à vida. Entretanto, este evento é facilmente observável e provavelmente não demandaria maiores monitoramentos. Visto que o início do metabolismo anaeróbico é indicado pelo aumento súbito do quociente respiratório e que a faixa normal do quociente respiratório é ampla, o uso do ponto de corte definido como 1,4 para Pcv-aCO2/Ca-cvO2 não faz sentido. Estudos experimentais demonstraram que a Pcv-aCO2/Ca-cvO2 é mais dependente de fatores que modificam a dissociação do dióxido de carbono da hemoglobina do que do quociente respiratório, e o quociente respiratório e Pcv-aCO2/Ca-cvO2 podem ter comportamentos distintos. Estudos conduzidos em pacientes críticos demonstraram resultados controvertidos com relação à capacidade da Pcv-aCO2/Ca-cvO2 para predizer o desfecho, hiperlactatemia, anomalias microvasculares e dependência de suprimento de oxigênio. Um estudo randomizado controlado também demonstrou que a Pcv-aCO2/Ca-cvO2 é inútil como alvo para ressuscitação. A Pcv-aCO2/Ca-cvO2 deve ser interpretada com cautela em pacientes críticos.

ABSTRACT The central venous minus arterial carbon dioxide pressure to arterial minus central venous oxygen content ratio (Pcv-aCO2/Ca-cvO2) has been proposed as a surrogate for respiratory quotient and an indicator of tissue oxygenation. Some small observational studies have found that a Pcv-aCO2/Ca-cvO2 > 1.4 was associated with hyperlactatemia, oxygen supply dependency, and increased mortality. Moreover, Pcv-aCO2/Ca-cvO2 has been incorporated into algorithms for tissue oxygenation evaluation and resuscitation. However, the evidence for these recommendations is quite limited and of low quality. The goal of this narrative review was to analyze the methodological bases, the pathophysiologic foundations, and the experimental and clinical evidence supporting the use of Pcv-aCO2/Ca-cvO2 as a surrogate for respiratory quotient. Physiologically, the increase in respiratory quotient secondary to critical reductions in oxygen transport is a life-threatening and dramatic event. Nevertheless, this event is easily noticeable and probably does not require further monitoring. Since the beginning of anaerobic metabolism is indicated by the sudden increase in respiratory quotient and the normal range of respiratory quotient is wide, the use of a defined cutoff of 1.4 for Pcv-aCO2/Ca-cvO2 is meaningless. Experimental studies have shown that Pcv-aCO2/Ca-cvO2 is more dependent on factors that modify the dissociation of carbon dioxide from hemoglobin than on respiratory quotient and that respiratory quotient and Pcv-aCO2/Ca-cvO2 may have distinct behaviors. Studies performed in critically ill patients have shown controversial results regarding the ability of Pcv-aCO2/Ca-cvO2 to predict outcome, hyperlactatemia, microvascular abnormalities, and oxygen supply dependency. A randomized controlled trial also showed that Pcv-aCO2/Ca-cvO2 is useless as a goal of resuscitation. Pcv-aCO2/Ca-cvO2 should be carefully interpreted in critically ill patients.

Emissões fugitivas de biogás em camada de cobertura de solo compactado em aterro sanitário / Fugitive emissions of biogas in coverage liner of compacted soil in a landfill

RESUMO As emissões fugitivas de biogás podem representar parcela significativa do fluxo de gases em aterros sanitários, inviabilizar o aproveitamento energético do metano (CH4), além de oferecer riscos à saúde ambiental das comunidades circunvizinhas ao empreendimento. Nesse contexto, este trabalho teve por objetivo avaliar as emissões fugitivas e os fatores que interferem no fluxo de biogás em camada de cobertura final (liner) de aterro sanitário. A área de estudo consistiu em uma célula de resíduos, com massa de 62.359,44 t de resíduos sólidos urbanos (RSU) depositados, no aterro sanitário de Campina Grande, Paraíba, Brasil. Nessa célula, foram realizadas medições das emissões fugitivas de biogás, por meio da metodologia de placa de fluxo estática, análises das concentrações de gases na interface solo-resíduo, utilizando dispositivos de medição de concentração de gases (DMC) e mapeamentos das emissões de gases na célula de resíduos, aplicando técnicas de interpolação de dados baseada na Krigagem. Foram verificados fluxos de CH4 e dióxido de carbono (CO2) variando de 0 a 0,09 e 24,62 a 331,31 g.m-2.dia-1, respectivamente. O percentual de retenção do CH4 e do CO2 pela liner foi elevado, acima de 95%, sendo influenciado principalmente pelo elevado grau de compactação (GC) médio obtido para a célula (91,84%) e pela eficiência do sistema de drenagem de gases. O mapeamento das emissões de biogás na célula de resíduos mostrou-se uma ferramenta importante na identificação das áreas com maior potencial de geração e de fluxo de biogás pela camada de cobertura.

ABSTRACT Fugitive biogas emissions can represent a significant part of the gas flow in landfills, make the methane (CH4) energy use unfeasible, and also pose risks to the environmental health of the surrounding communities. In this context, this work aimed to evaluate the fugitive emissions and the factors that interfere in the biogas flow in the final landfill liner. The study area consisted of a Waste Cell, with a mass of 62,359.44 t of MSW deposited at the Campina Grande Sanitary Landfill, Paraíba, Brazil. In this Cell, measurements of the fugitive emissions of biogas were carried out, using the static chamber methodology; analysis of the concentration of gases at the soil-waste interface, using Gas Concentration Measurement Devices (CMD); and mapping of the gas emissions in the Waste Cell, applying data interpolation techniques based on Kriging. Flows of CH4 and carbon dioxide (CO2) ranging from 0 to 0.09 and 24.62 to 331.31 g.m-2.day-1, respectively. The percentage of retention of CH4 and CO2 by the liner was high, above 95%, being influenced mainly by the high degree of average compaction obtained for the Waste Cell (91.84%) and by the efficiency of the gas drainage system. The mapping of biogas emissions in the Waste Cell proved to be an important tool in the identification of the areas with the greatest potential for biogas generation and flow through the cover liner.

Embolia de dióxido de carbono / Carbon dioxide embolism

Carbon dioxide (CO) embolism is a complication of laparoscopic surgery that, although often does not have adverse sequelae, can be fatal. This is due to the fact that when CO is injected into the blood vessels, the bubbles impede blood flow, which clinically expresses as: decreased stroke volume, hypoxemia, sudden fall or sudden increase in expired CO, bradycardia, hypotension, dyspnea, cyanosis, arrhythmias, bilateral mydriasis, murmur in a mill wheel at auscultation and cardiovascular collapse with cardiorespiratory arrest. In this article we will present physiology of venous embolism, diagnosis, syntoms, treatment and prevention.

La embolia por dióxido de carbono (CO) es una complicación de la cirugía laparoscópica que, aunque a menudo no presenta secuelas adversas, puede ser fatal. Esto se debe a que al inyectar CO en los vasos sanguíneos las burbujas impiden el flujo de sangre, lo que clínicamente se expresa como: disminución del volumen sistólico, hipoxemia, caída repentina o aumento súbito del CO espirado, bradicardia, hipotensión, disnea, cianosis, arritmias, midriasis bilateral, soplo en rueda de molino a la auscultación y al colapso cardiovascular con paro cardiorrespiratorio. En este trabajo presentaremos fisiología del embolismo venoso, cuadro clínico, diagnóstico, tratamiento y formas de prevenir que ocurra este evento.

Use of carbon dioxide for therapeutic decision-making in endoleaks: a case report / Uso de CO2 na tomada de decisão terapêutica de endoleak: relato de caso

Abstract Endovascular aneurysm repair is currently the most frequently treatment modality for infrarenal aortic aneurysms. Endoleaks are the most common cause of reintervention after endovascular aneurysm repair. It is often unclear which type of endoleak is the correct diagnose, making the treatment decision difficult. We report the case of a 72-year-old man with an endoleak two years after endovascular aneurysm repair. Images suggested a type III endoleak, but this was not confirmed by contrast aortography. We proceeded with the investigation using aortography with carbon dioxide and observed a type IA endoleak. This was successfully treated by implantation of a proximal cuff. A review of the literature shows that the role of carbon dioxide in endoleak management is still unclear. We present a case in which carbon dioxide was essential to both diagnosis and therapeutic decision-making in a type IA endoleak.

Resumo O tratamento endovascular dos aneurismas de aorta abdominal é atualmente a modalidade de tratamento mais comum. Os endoleaks representam a causa mais frequente de reintervenção após o tratamento endovascular. O diagnóstico do tipo de endoleak frequentemente é incerto, tornando o tratamento desafiador. Apresentamos o caso de um paciente de 72 anos, com endoleak após 2 anos de tratamento endovascular de aneurisma de aorta abdominal. Os exames de imagem pré-operatórios sugeriam um endoleak tipo III; entretanto, durante aortografia com contraste iodado, não foi possível identificá-lo. Optamos por realizar aortografia com dióxido de carbono (CO2), sendo, então, identificado um endoleak tipo IA, que foi tratado com sucesso com o uso de uma extensão (cuff) proximal. O papel do CO2 no diagnóstico de endoleaks ainda não está claro. Relatamos um caso em que o uso do CO2 foi essencial para o diagnóstico e para a decisão de tratamento do endoleak tipo IA.

Evaluación del dolor y la distensión abdominal según el agente insuflante (CO 2 frente al aire) en una unidad de endoscopia digestiva avanzada de Manizales, Colombia / Comparison of abdominal pain and distention due to insufflation with CO 2 versus insufflation with air in an advanced digestive endoscopy unit in Manizales, Colombia

Resumen Objetivo: comparar la magnitud del dolor y el perímetro abdominal; la incidencia del dolor y la distensión abdominal, y las complicaciones según el agente insuflante utilizado. Pacientes y método: estudio prospectivo analítico de cohorte. Se recolectaron datos de 43 colangiopancreatografías retrógradas endoscópicas (CPRE) y 20 colonoscopias insufladas con dióxido de carbono (CO2); para cada una se buscó un examen control con aire ambiente. En total, se sumaron 86 CPRE y 40 colonoscopias. Además, se realizó una caracterización clínica, un análisis bivariado y multivariado. Resultados: el procedimiento más doloroso fue la colonoscopia; sin embargo, el 60 % de los pacientes de colonoscopia, y el 70 % de aquellos de CPRE, no presentaron dolor 15 minutos después de haber despertado luego del examen. Asimismo, no se hallaron diferencias estadísticamente significativas según la indicación del examen, la presencia o intensidad de dolor al momento del procedimiento, la edad, el sexo o el diagnóstico. El riesgo relativo (RR) de dolor inmediato fue 4,8 veces superior, cuando la insuflación se realizó con aire en vez de CO2 (RR = 4,8; intervalo de confianza [IC], 95 %: 2,3 a 9,2; p <0,001). Entre tanto, el riesgo de distensión abdominal en el grupo con aire fue 2,6 veces superior, en comparación con el grupo insuflado con CO2 (RR = 2,6; IC, 95 %: 1,8 a 3,9; p <0,001). El CO2 redujo la probabilidad y la magnitud de la distensión abdominal y de los dolores inmediatos, posteriores a la colonoscopia o a la CPRE. No hubo complicaciones en ninguno de los 126 pacientes. Conclusiones: el dolor y la distensión abdominal se presentan con menor frecuencia e intensidad cuando se usa CO2 como agente insuflante. Ninguno de los procedimientos presentó complicaciones mayores.

Abstract Objective: This study compares the incidence of abdominal pain and distension, the magnitude of pain, abdominal perimeter, and related complications related to two different insufflating agents. Patients and Method: Prospective analytical cohort study. Data were collected from 43 performances of endoscopic retrograde cholangiopancreatography (ERCPs) and 20 colonoscopies in which patients were insufflated with CO2. A control examination using ambient air for insufflation was performed for each patient. In total, 86 ERCPs and 40 colonoscopies were performed. The study includes clinical characterizations, bivariate analysis and multivariate analysis. Results: The most painful procedure was colonoscopy, but 60% of colonoscopy patients and 70% of ERCP patients had no pain 15 minutes after waking up following their examinations. No statistically significant differences related to reasons for examination, presence or intensity of pain at the time of the procedure, age, sex or diagnosis were found. The relative risk (RR) of immediate pain is 4.8 times higher when insufflation is done with air instead of CO2 (RR = 4.8; 95% CI: 2.3 to 9.2; p <0.001). The risk of abdominal distension in the air group was 2.6 times higher than that of the group insufflated with CO2 (RR = 2.6; 95% CI: 1.8 to 3.9; p <0.001). CO2 reduces the likelihood and extent of abdominal distension and immediate post colonoscopy or ERCP pain. There were no complications in any of the 126 patients. Conclusions: Abdominal pain and bloating occur less frequently and less intensely when CO2 is used as an insufflating agent. None of the procedures presented major complications.

Láser CO2 ablativo en angiofibroma facial por esclerosis tuberosa / Ablative laser CO2 in facial angiofibroma due to tuberous sclerosis

Se presenta el caso de un paciente de 25 años con múltiples pápulas y placas de aspecto fibroso, distribuidas principalmente en cara, además de cuero cabelludo, tórax y región periungueal pedia, asintomático. Se realizó el diagnóstico clínico e histopatológico de esclerosis tuberosa, enfermedad genética poco frecuente. Se utilizó láser CO2 modo ablativo en 2 ciclos de dos sesiones cada una, en lesiones cutáneas faciales (angiofibroma facial), con el objetivo de mejorar la apariencia y promover calidad de vida. Como resultado se evidenció mejoría de la apariencia y ausencia de recidiva con un método terapéutico moderno y aún inaccesible a todas las personas en nuestro país.

We present the case of a 25-year-old patient with multiple fibrous papules and plaques, mainly distributed on the face, as well as asymptomatic scalp, thorax and peduncle periungueal region. The clinical and histopathological diagnosis of tuberous sclerosis was performed, a rare genetic disease. CO2 laser was used ablative mode in 2 cycles of two sessions each, in facial skin lesions (facial angiofibroma), with the aim of improving the appearance and promoting quality of life. As a result, improvement in the appearance and absence of recurrence was evidenced by a modern therapeutic method that is still inaccessible to all people in our country.