RESUMO
OBJECTIVE: To compare two methods for defining and classifying the severity of pediatric acute respiratory distress syndrome: the Berlin classification, which uses the relationship between the partial pressure of oxygen and the fraction of inspired oxygen, and the classification of the Pediatric Acute Lung Injury Consensus Conference, which uses the oxygenation index. METHODS: This was a prospective study of patients aged 0 - 18 years with a diagnosis of acute respiratory distress syndrome who were invasively mechanically ventilated and provided one to three arterial blood gas samples, totaling 140 valid measurements. These measures were evaluated for correlation using the Spearman test and agreement using the kappa coefficient between the two classifications, initially using the general population of the study and then subdividing it into patients with and without bronchospasm and those with and without the use of neuromuscular blockers. The effect of these two factors (bronchospasm and neuromuscular blocking agent) separately and together on both classifications was also assessed using two-way analysis of variance. RESULTS: In the general population, who were 54 patients aged 0 - 18 years a strong negative correlation was found by Spearman's test (ρ -0.91; p < 0.001), and strong agreement was found by the kappa coefficient (0.62; p < 0.001) in the comparison between Berlin and Pediatric Acute Lung Injury Consensus Conference. In the populations with and without bronchospasm and who did and did not use neuromuscular blockers, the correlation coefficients were similar to those of the general population, though among patients not using neuromuscular blockers, there was greater agreement between the classifications than for patients using neuromuscular blockers (kappa 0.67 versus 0.56, p < 0.001 for both). Neuromuscular blockers had a significant effect on the relationship between the partial pressure of oxygen and the fraction of inspired oxygen (analysis of variance; F: 12.9; p < 0.001) and the oxygenation index (analysis of variance; F: 8.3; p = 0.004). CONCLUSION: There was a strong correlation and agreement between the two classifications in the general population and in the subgroups studied. Use of neuromuscular blockers had a significant effect on the severity of acute respiratory distress syndrome.
Assuntos
Síndrome do Desconforto Respiratório , Índice de Gravidade de Doença , Humanos , Criança , Lactente , Adolescente , Pré-Escolar , Estudos Prospectivos , Feminino , Masculino , Síndrome do Desconforto Respiratório/classificação , Síndrome do Desconforto Respiratório/diagnóstico , Recém-Nascido , Lesão Pulmonar Aguda/classificação , Lesão Pulmonar Aguda/diagnóstico , Respiração Artificial , Bloqueadores Neuromusculares/uso terapêutico , Gasometria/métodos , Espasmo Brônquico , ConsensoRESUMO
INTRODUCTION: We evaluated the effects of pre-analytical care on total carbon dioxide (tCO2 ) in hemodialysis patients, as calculated by blood gas analysis (ctCO2 ) or measured by an enzymatic assay (mtCO2 ). METHODS: Blood samples were collected via vascular access before dialysis sessions. For blood gas analysis, eight aliquots were collected, refrigerated or non-refrigerated, and analyzed at 0, 4, 8, and 24 h after collection. A blood sample was then collected for the enzymatic method and distributed into 14 aliquots. Half of the aliquots were refrigerated. The samples analyzed at time point 0 were centrifuged immediately. The remaining aliquots of both the refrigerated and non-refrigerated clusters were centrifuged before storage. Samples were analyzed at 4, 8, and 24 h post-collection. FINDINGS: By blood gas analysis, no significant change was found in bicarbonate values over time, either in the non-refrigerated or refrigerated samples. ctCO2 values during the experiment showed a minor but statistically significant increase of questionable clinical relevance in both non-refrigerated and refrigerated aliquots. In the enzymatic assay, the reduction in mtCO2 levels during the experiment was negligible. The median absolute reductions at the end of the experiment were 1.77, 1.21, 1.04, and 1.12 mmol/L for the non-centrifuged/non-refrigerated, centrifuged/non-refrigerated, non-centrifuged/refrigerated, and centrifuged/refrigerated aliquots, respectively. DISCUSSION: Our results suggest that measured or calculated tCO2 levels of capped and cooled samples are adequate for analyzing the acid-base status of hemodialysis patients, even when such determination is not performed immediately after collection.
Assuntos
Acidose , Diálise Renal , Humanos , Dióxido de Carbono , Gasometria/métodos , BicarbonatosRESUMO
Introducción: la monitorización hemodinámica constituye un conjunto de técnicas y parámetros que permiten valo rar si la función cardiovascular es la adecuada para mantener la perfusión y la oxigenación tisular que permita sa tisfacer las demandas metabólicas del organismo, valorar el estado y el comportamiento del sistema cardiovascular, orientando sobre la mejor estrategia terapéutica. La presente revisión busca proporcionar una descripción general e integrada de las diferentes técnicas de monitorización, así como aspectos fisiológicos relevantes para su entendi miento y empleo terapéutico. La monitorización hemodinámica acompañada de un adecuado conocimiento de la fisiología cardiovascular permite determinar el estado del sistema cardiovascular, la condición hemodinámica del paciente y la estrategia terapéutica requerida. Su interpretación debe partir de la integración y la correlación de diversos parámetros hemodinámicos.
Introduction: hemodynamic monitoring is a set of techniques and parameters that allow evaluating whether cardio vascular function is adequate to maintain tissue perfusion and oxygenation to satisfy metabolic demands of the or ganism, assess the condition and behavior of the cardiovascular system, providing guidance on the best therapeutic strategy. This review seeks to provide a general and integrated description of the different monitoring techniques, as well as physiological aspects relevant to their understanding and therapeutic use. Hemodynamic monitoring accompanied by an adequate knowledge of cardiovascular physiology allows to determine the state of the cardiovascular system, hemodynamic condition of the patient and therapeutic strategy required, its interpretation must start from the integration and correlation of different hemodynamic parameters.
Introdução: a monitorização hemodinâmica constitui um conjunto de técnicas e parâmetros que permitem avaliar se a função cardiovascular é adequada para manter a perfusão e oxigenação tecidual que permite satisfazer as exi gências metabólicas do organismo, avaliar o estado e comportamento do sistema cardiovascular, orientando sobre a melhor estratégia terapêutica. Esta revisão procura fornecer uma descrição geral e integrada das diferentes técnicas de monitorização, bem como aspectos fisiológicos relevantes para a sua compreensão e utilização terapêutica. A monitorização hemodinâmica acompanhada de um conhecimento adequado da fisiologia cardiovascular permite determinar o estado do sistema cardiovascular, a condição hemodinâmica do doente e a estratégia terapêutica neces sária, a sua interpretação deve partir da integração e correlação de vários parâmetros hemodinâmicos.
Assuntos
Humanos , Fenômenos Fisiológicos Cardiovasculares , Estado Terminal/terapia , Monitorização Hemodinâmica/métodos , Gasometria/métodos , Ecocardiografia/métodos , Cuidados Críticos/métodosRESUMO
Introducción: Las alteraciones del equilibrio ácido-base pueden ser de carácter primario. En la mayoría de los casos dependen de la complicación de una enfermedad preexistente. La frecuencia de estos trastornos es elevada, especialmente, en enfermos hospitalizados en las unidades de atención al paciente grave. Su aparición conlleva implicaciones pronósticas significativas. Objetivo: Sistematizar sobre el estado actual del manejo del equilibrio ácido-base. Método: Se realizó una revisión bibliográfica en la que se utilizaron las herramientas del método científico. Se examinó toda la bibliografía disponible publicada en los últimos cinco años y así, elaborar una síntesis crítica, acorde al criterio y las competencias de los autores sobre la temática. Resultados: Se expone la importancia de la evaluación clínica, que unida a los niveles de PCO2, y de exceso o déficit de bases en una gasometría arterial, permiten identificar el trastorno ácido base existente. Igualmente, se destaca que el CO2 tiene una función clave en el control de la ventilación, así como las modificaciones que produce al flujo sanguíneo cerebral, el pH y el tono adrenérgico. Otro aspecto importante fue la reciente práctica clínica de la "hipercapnia permisiva" para reducir el metabolismo tisular y de esta manera, mejorar la función del surfactante e impedir la nitración de las proteínas. Conclusiones: El manejo de los desequilibrios ácido-base debe ser del dominio de todos los profesionales vinculados a la asistencia médica, pues el retraso de su diagnóstico puede empeorar la evolución y el pronóstico de los pacientes graves(AU)
Introduction: Acid-base balance alterations can be of a primary nature. In most cases, they depend on the complication of a pre-existing disease. The frequency of these disorders is high, especially in patients hospitalized in critical care units. Its appearance carries significant prognostic implications. Objective: To systematize the current state of acid-base balance management. Method: A bibliographic review was carried out, for which the tools of the scientific method were used. All the available bibliography, published in the last five years, was examined; thus, a critical synthesis was prepared, according to the criteria and competences of the authors regarding the subject. Results: The importance of the clinical evaluation is exposed, which, together with PCO2 levels as well as excess or deficit of bases in an arterial blood gas, allow to identify the existing acid-base disorder. Likewise, it is highlighted that CO2 has a key function in ventilation control, together with the modifications it produces on cerebral blood flow, pH and adrenergic tone. Another important aspect was the recent clinical practice of "permissive hypercapnia" to reduce tissue metabolism and thus improve surfactant function and prevent protein nitration. Conclusions: The management of acid-base imbalances should be mastered by all professionals associated to medical care, since any delay in its diagnosis can worsen the evolution and prognosis of seriously ill patients(AU)
Assuntos
Humanos , Masculino , Feminino , Equilíbrio Ácido-Base , Desequilíbrio Ácido-Base , Gasometria/métodos , Cuidados Críticos , Cuidados Médicos , Concentração de Íons de HidrogênioRESUMO
INTRODUCTION: Arterial blood gas analysis (ABG) is the gold standard test for carbon dioxide measurement. End-tidal PCO2 (PetCO2 ) and transcutaneous PCO2 (PtcCO2 ) are noninvasive alternative methods. OBJECTIVE: To examine the use of PetCO2 and PtcCO2 as PaCO2 surrogates in awake children. METHODS: A prospective observational study. Consecutive awake children in a stable condition referred to the Sleep Unit of Hospital de Pediatría Dr. J. P. Garrahan with suspected or confirmed sleep-related respiratory disorders requiring ABG were included. PetCO2 and PtcCO2 were recorded simultaneously during arterial puncture. PetCO2 and PtCO2 values were compared with PaCO2 . Correlation coefficient and Bland-Altman analysis were applied. The sample size was calculated considering a mean difference ≤3 mmHg as clinically acceptable. RESULTS: Sixty-eight sample sets were obtained from 67 patients. The median age was 9.11 years (0.23-18.76). During 94.1% of the procedures patients breathed spontaneously, 30% needed multiple punctures and 92% resulted in pain. Median (IQR) PaCO2 (mmHg) was 36.3 (31.45; 40.90), PetCO2 33.0 (29; 39) and PtcCO2 38.8 (32.95; 43.32). Correlation and agreement for PaCO2 /PetCO2 and PaCO2 /PtcCO2 was r = .6 and .9, and media of bias = 2.83 (-9.97; 15.64) and -1.88 (-9.01; 5.24), respectively. Hypercapnia (PaCO2 > 45.0 mmHg) was present in 8/68 (11.8%) samples. Sensitivity, specificity, positive predictive value and negative predictive value to detect hypercapnia with PetCO2 was 38%, 98%, 75%, and 92%, respectively, and with PtcCO2 , 100%, 90%, 57%, and 100%, respectively. CONCLUSION: PtcCO2 showed better agreement with PaCO2 than PetCO2 but because of the wide dispersion of values, neither method can replace the gold standard. Transcutaneous CO2 might be a good screening tool to detect hypercapnia in awake children.
Assuntos
Gasometria/métodos , Dióxido de Carbono/sangue , Hipercapnia/diagnóstico , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Hipercapnia/sangue , Lactente , Masculino , VigíliaRESUMO
PURPOSE: Arterial blood gases (ABG) are influenced by the altitude above sea level, age and sex. Most studies have been conducted at sea level and in small populations ascending to or residents at very high altitudes. Our objective was to evaluate the ventilation and ABG by age and sex in an Andean population resident at high altitude (2640 m). METHODS: Analytical cross-sectional study was done in healthy volunteers. ABG and minute ventilation (VE) were measured. T test and ANOVA for differences by sex and age, and Pearson test for correlations between age, VE and ABG were performed. RESULTS: We included 374 adults, 55% women from 18 to 83 years and hemoglobin of 15.7 ± 1.6 g/dl. There was a significant decrease in PaO2 and SaO2 and an increase in P(A - a)O2 with age (p < 0.001). Unlike men, with age women had a significant increase in PaCO2 and a higher decrease in PaO2. The correlations between age, the decrease in PaO2 and the increase in PaCO2 were greater in women than in men. The VE adjusted to body surface area decreased with age, but this correlation was significantly higher in women. CONCLUSIONS: In this study, with a considerable number of healthy adults living at high altitude (2640 m), we established the physiological impact of altitude, aging and gender in ABG. The PaO2 and PaCO2 were significantly lower and the hemoglobin values slightly higher than described at sea level. In addition to PaO2 decline with age, there was an age-related increase in PaCO2 in women, associated with a greater reduction of VE.
Assuntos
Artérias/metabolismo , Artérias/fisiologia , Oxigênio/sangue , Descanso/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Altitude , Gasometria/métodos , Estudos Transversais , Feminino , Hemoglobinas/metabolismo , Humanos , Pulmão/metabolismo , Pulmão/fisiologia , Masculino , Pessoa de Meia-Idade , Respiração , Adulto JovemRESUMO
The apnea test, which involves disconnection from the mechanical ventilator, presents risks during the determination of brain death, especially in hypoxemic patients. We describe the performance of the apnea test without disconnection from the mechanical ventilator in two patients. The first case involved an 8-year-old boy admitted with severe hypoxemia due to pneumonia. He presented with cardiorespiratory arrest, followed by unresponsive coma due to hypoxic-ischemic encephalopathy. Two clinical exams revealed the absence of brainstem reflexes, and transcranial Doppler ultrasound revealed brain circulatory arrest. Three attempts were made to perform the apnea test, which were interrupted by hypoxemia; therefore, the apnea test was performed without disconnection from the mechanical ventilator, adjusting the continuous airway pressure to 10cmH2O and the inspired fraction of oxygen to 100%. The oxygen saturation was maintained at 100% for 10 minutes. Posttest blood gas analysis results were as follows: pH, 6.90; partial pressure of oxygen, 284.0mmHg; partial pressure of carbon dioxide, 94.0mmHg; and oxygen saturation, 100%. The second case involved a 43-year-old woman admitted with subarachnoid hemorrhage (Hunt-Hess V and Fisher IV). Two clinical exams revealed unresponsive coma and absence of all brainstem reflexes. Brain scintigraphy showed no radioisotope uptake into the brain parenchyma. The first attempt at the apnea test was stopped after 5 minutes due to hypothermia (34.9°C). After rewarming, the apnea test was repeated without disconnection from the mechanical ventilator, showing maintenance of the functional residual volume with electrical bioimpedance. Posttest blood gas analysis results were as follows: pH, 7.01; partial pressure of oxygen, 232.0mmHg; partial pressure of carbon dioxide, 66.9mmHg; and oxygen saturation, 99.0%. The apnea test without disconnection from the mechanical ventilator allowed the preservation of oxygenation in both cases. The use of continuous airway pressure during the apnea test seems to be a safe alternative in order to maintain alveolar recruitment and oxygenation during brain death determination.
Assuntos
Apneia/diagnóstico , Morte Encefálica/diagnóstico , Pressão Positiva Contínua nas Vias Aéreas/métodos , Adulto , Gasometria/métodos , Dióxido de Carbono/sangue , Criança , Feminino , Humanos , Hipóxia/diagnóstico , Masculino , Oxigênio/sangue , Pressão Parcial , Respiração ArtificialRESUMO
RESUMO O teste de apneia com desconexão do ventilador mecânico representa riscos durante a determinação da morte encefálica, especialmente em pacientes hipoxêmicos. Descrevemos a realização do teste de apneia sem desconexão do ventilador mecânico em dois pacientes. O primeiro caso é o de um menino de 8 anos, admitido com hipoxemia grave por pneumonia. Apresentou parada cardiorrespiratória, seguida de coma não responsivo por encefalopatia hipóxico-isquêmica. Dois exames clínicos constataram ausência de reflexos de tronco, e o Doppler transcraniano revelou parada circulatória encefálica. Realizaram-se três tentativas de teste de apneia, que foram interrompidas por hipoxemia, sendo então realizado teste de apneia sem desconexão do ventilador mecânico, ajustando a pressão contínua nas vias aéreas em 10cmH2O e fração inspirada de oxigênio em 100%. A saturação de oxigênio manteve-se em 100% por 10 minutos. A gasometria pós-teste foi a seguinte: pH de 6,90, pressão parcial de oxigênio em 284,0mmHg, pressão parcial de dióxido de carbono em 94,0mmHg e saturação de oxigênio em 100%. O segundo caso é de uma mulher de 43 anos, admitida com hemorragia subaracnóidea (Hunt-Hess V e Fisher IV). Dois exames clínicos constataram coma não responsivo e ausência de todos os reflexos de tronco. A cintilografia cerebral evidenciou ausência de captação de radioisótopos no parênquima cerebral. A primeira tentativa do teste de apneia foi interrompida após 5 minutos por hipotermia (34,9oC). Após reaquecimento, o teste de apneia foi repetido sem desconexão do ventilador mecânico, evidenciando-se manutenção do volume residual funcional com tomografia de bioimpedância elétrica. Gasometria pós-teste de apneia apresentava pH em 7,01, pressão parcial de oxigênio em 232,0mmHg, pressão parcial de dióxido de carbono 66,9mmHg e saturação de oxigênio em 99,0%. O teste de apneia sem desconexão do ventilador mecânico permitiu a preservação da oxigenação em ambos os casos. O uso de pressão contínua nas vias aéreas durante o teste de apneia parece ser uma alternativa segura para manter o recrutamento alveolar e a oxigenação durante determinação da morte encefálica.
ABSTRACT The apnea test, which involves disconnection from the mechanical ventilator, presents risks during the determination of brain death, especially in hypoxemic patients. We describe the performance of the apnea test without disconnection from the mechanical ventilator in two patients. The first case involved an 8-year-old boy admitted with severe hypoxemia due to pneumonia. He presented with cardiorespiratory arrest, followed by unresponsive coma due to hypoxic-ischemic encephalopathy. Two clinical exams revealed the absence of brainstem reflexes, and transcranial Doppler ultrasound revealed brain circulatory arrest. Three attempts were made to perform the apnea test, which were interrupted by hypoxemia; therefore, the apnea test was performed without disconnection from the mechanical ventilator, adjusting the continuous airway pressure to 10cmH2O and the inspired fraction of oxygen to 100%. The oxygen saturation was maintained at 100% for 10 minutes. Posttest blood gas analysis results were as follows: pH, 6.90; partial pressure of oxygen, 284.0mmHg; partial pressure of carbon dioxide, 94.0mmHg; and oxygen saturation, 100%. The second case involved a 43-year-old woman admitted with subarachnoid hemorrhage (Hunt-Hess V and Fisher IV). Two clinical exams revealed unresponsive coma and absence of all brainstem reflexes. Brain scintigraphy showed no radioisotope uptake into the brain parenchyma. The first attempt at the apnea test was stopped after 5 minutes due to hypothermia (34.9°C). After rewarming, the apnea test was repeated without disconnection from the mechanical ventilator, showing maintenance of the functional residual volume with electrical bioimpedance. Posttest blood gas analysis results were as follows: pH, 7.01; partial pressure of oxygen, 232.0mmHg; partial pressure of carbon dioxide, 66.9mmHg; and oxygen saturation, 99.0%. The apnea test without disconnection from the mechanical ventilator allowed the preservation of oxygenation in both cases. The use of continuous airway pressure during the apnea test seems to be a safe alternative in order to maintain alveolar recruitment and oxygenation during brain death determination.
Assuntos
Humanos , Masculino , Feminino , Criança , Adulto , Apneia/diagnóstico , Morte Encefálica/diagnóstico , Pressão Positiva Contínua nas Vias Aéreas/métodos , Oxigênio/sangue , Pressão Parcial , Respiração Artificial , Gasometria/métodos , Dióxido de Carbono/sangue , Hipóxia/diagnósticoRESUMO
OBJECTIVE: To compare the Element point-of-care (POC) portable blood gas analyzer with a laboratory-based bench-top reference analyzer using whole blood samples obtained from horses presenting to a referral center with various disorders in order to determine agreement between these analyzers. DESIGN: Prospective clinical study. SETTING: The study was conducted at a university teaching hospital at moderate altitude. ANIMALS: One hundred paired samples from 80 horses >1 year of age were collected after obtaining informed client consent. Fifty paired samples were from patients admitted for elective procedures and considered to be healthy, and 50 paired samples were emergency admissions and considered to be critically ill. MEASUREMENTS AND MAIN RESULTS: Paired whole blood samples were evaluated on both the Element POC and Radiometer ABL 800 FLEX analyzers simultaneously, and results were compared. Pearson correlation coefficients between analyzers were calculated. To assess agreement, scatter and Bland-Altman plots were evaluated, and mean difference and 95% limits of agreement were calculated for each analyte. Correlation was either good (0.8-0.92) or excellent (>0.93) for the majority of analytes. All analytes apart from hemoglobin had acceptable agreement, with ≥80% of individual results within agreement targets. Precision targets were acceptable for most analytes, with partial pressure of carbon dioxide (pCO2 ) and calcium (Ca2+ ) exceeding precision targets. CONCLUSIONS: The portable Element POC system had acceptable agreement with the ABL 800 FLEX bench-top analyzer currently in use at the study center when evaluating the majority of analytes from equine whole blood samples.
Assuntos
Gasometria/veterinária , Cavalos/sangue , Sistemas Automatizados de Assistência Junto ao Leito , Animais , Gasometria/instrumentação , Gasometria/métodos , Cálcio , Dióxido de Carbono/sangue , Hemoglobinas , Pressão Parcial , Estudos ProspectivosRESUMO
OBJECTIVE: To evaluate serum biochemical parameters' evolution, especially venous blood gas (VBG), in anorexia nervosa (AN), correlating with clinical parameters. METHODS: Retrospective study including out-patient AN adolescents, between January 2014 and May 2017. Three evaluations were compared: t1) first consultation; t2) consultation with the lowest body mass index (BMI) z-score and t3) with the highest BMI z-score. RESULTS: A total of 24 adolescents (87.5% females) were included, mean age of presentation of 14.9±1.7 years, onset of symptoms 6.4±3.2 months before the first visit. In t1, BMI z-score of -1.91±1.11 kg/m2 and ideal weight % of 84.3±9.2. Amenorrhea was present in 88%. In t2 the analytical alterations were: altered VBG in 100%, altered ferritin (72% elevated), altered thyroid function (53% with thyroxine decrease), dyslipidemia (31% elevation of high density lipoprotein, 25% hypercholesterolemia), elevation of urea (25%), elevation of alanine aminotransferase (14%), hypoglycemia (14%), anemia (9%). Respiratory acidosis was present in 91% in t1, 100% in t2 and 94% in t3. There was a significant decrease between t2 and t3 in mean pCO2 (57.2 versus 53.6 mmHg; p=0.009) and mean HCO3 (30.0 versus 28.8 mEq/L; p=0.023). CONCLUSIONS: Respiratory acidosis and increased ferritin were common in this group. Respiratory acidosis was the most frequent abnormality with significant pCO2 and HCO3 variation in the recovery phase. VBG should be considered in AN evaluation, once it seems to be important in assessing the severity of the disease and its subsequent follow-up.