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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.
Asunto(s)
Síndrome de Dificultad Respiratoria , Índice de Severidad de la Enfermedad , Humanos , Niño , Lactante , Adolescente , Preescolar , Estudios Prospectivos , Femenino , Masculino , Síndrome de Dificultad Respiratoria/clasificación , Síndrome de Dificultad Respiratoria/diagnóstico , Recién Nacido , Lesión Pulmonar Aguda/clasificación , Lesión Pulmonar Aguda/diagnóstico , Respiración Artificial , Bloqueantes Neuromusculares/uso terapéutico , Análisis de los Gases de la Sangre/métodos , Espasmo Bronquial , ConsensoRESUMEN
ABSTRACT 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.
RESUMO Objetivo Comparar dois métodos para definição e classificação de gravidade na síndrome do desconforto respiratório agudo pediátrica: a classificação de Berlim, que utiliza a relação entre pressão parcial de oxigênio e fração inspirada de oxigênio e a classificação do Pediatric Acute Lung Injury Consensus Conference, que utiliza o índice de oxigenação. Métodos Estudo prospectivo com pacientes de 0 - 18 anos com diagnóstico de síndrome do desconforto respiratório agudo e ventilados mecanicamente de forma invasiva, que forneceram de uma a três amostras de gasometria arterial, totalizando 140 medidas válidas. Essas medidas foram avaliadas quanto à correlação pelo teste de Spearman e à concordância pelo coeficiente kappa entre as duas classificações, inicialmente usando a população geral do estudo e, depois, subdividindo-a em pacientes com e sem broncoespasmo e com e sem o uso do bloqueador neuromuscular. Também foi verificado o efeito desses dois fatores (broncoespasmo e bloqueador neuromuscular) de forma separada e conjunta sobre ambas as classificações por meio da análise de variância para dois fatores. Resultados Na população geral, composta de 54 pacientes com idades de 0 - 18 anos, foi encontrada forte correlação negativa pelo teste de Spearman (ρ -0,91; p < 0,001) e forte concordância pelo coeficiente kappa (0,62; p < 0,001) na comparação entre Berlim e Pediatric Acute Lung Injury Consensus Conference. Nas populações com e sem broncoespasmo e com e sem o uso do bloqueador neuromuscular, os coeficientes de correlação mantiveram valores semelhantes aos da população geral. Entretanto, para os pacientes sem uso do bloqueador neuromuscular, houve maior concordância entre as classificações em relação aos pacientes com uso do bloqueador neuromuscular (kappa 0,67 versus 0,56 com p < 0,001 em ambos). Acrescenta-se ainda o efeito significativo do uso do bloqueador neuromuscular sobre a relação entre pressão parcial de oxigênio e fração inspirada de oxigênio (análise de variância; F: 12,9; p < 0,001) e o índice de oxigenação (análise de variância; F: 8,3; p = 0,004). Conclusão Houve forte correlação e concordância entre as duas classificações na população geral e nos subgrupos estudados, entretanto, há efeito significativo do uso do bloqueador neuromuscular sobre as classificações de gravidade da síndrome do desconforto respiratório agudo.
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Introdução: A Abertura e fechamento alveolar a cada ciclo respiratório (TR) é mecanismo de lesão pulmonar associada à ventilação mecânica. É frequente, especialmente em pacientes com lesão pulmonar aguda/ sindrome do desconforto respiratório agudo, mas pode ocorrer em pulmões normais, devido à pressão expiratória final positiva (PEEP) insuficiente. A fração inspirada de oxigênio (FiO2) também pode ter um papel na modulação da lesão pulmonar: frações mais baixas, em situação de relação ventilação perfusão (V/Q) crítica, podem retardar o colapso alveolar. A Tomografia de Impedância Elétrica (TIE) é uma nova ferramenta de imagem não invasiva, à beira do leito, que reconstrói imagens transversas da resistividade dos tecidos torácicos, obtidas a partir de uma corrente elétrica injetada por eletrodos colocados circunferencialmente no tórax. Atualmente, o padrão ouro de detecção de TR é a tomografia computadorizada (TC), que utiliza radiação, transporte de pacientes para sua execução, exigindo manobras que podem ocasionar a instabilização dos pacientes. Hipótese deste estudo: é possível detectar e quantificar a ocorrência de TR com TIE. Métodos: 7 suinos traqueostomizados, sob sedação, bloqueio neuromuscular e ventilação mecânica, foram submetidos a manobra de recrutamento alveolar (MRA) em pressão controlada, com pressão platô=50 cmH2O, PEEP=35 cmH2O, aplicada por 2 minutos. Seguiu-se ventilação com volume controlado, posição supina, volume corrente (VT) = 10 ml/kg, fluxo 10l/min FR=10irpm, FiO2=100% e PEEP decremental (20-10-3cmH2O), em passos de 10 minutos. Ao final de cada passo, os animais foram submetidos a uma pressão positiva contínua sobre as vias aéreas em dois níveis, quando se procedeu à TC: pressão de platô (representando inspiração) e PEEP (expiração). Imagens de TIE foram adquiridas continuamente. Os animais foram submetidos à nova MRA, repetindo-se o protocolo em FiO2=40%. Após lesão pulmonar (lavagem pulmonar com SF 0,9% até atingir SpO2< 95%)...
Introduction: Cyclic opening and closure of alveolar units during the respiratory cycle, or tidal recruitment (TR), is a harmful mechanism of ventilation induced lung injury. It is frequent, especially in acute lung injury and acute respiratory distress syndrome patients, but can occur in normal lungs under mechanical ventilation, because of an insufficient PEEP. Oxygen concentration (FiO2) can modulate collapse and low FiO2 can delay it. Electrical Impedance tomography (EIT) is a noninvasive imaging tool that reconstructs a cross-sectional image of lungs regional resistivity using electrodes placed around the thorax. EIT is a useful imaging tool for regional ventilation monitoring, as proved by many studies. We hypothesized that is possible to detect and quantify the occurrence of TR by EIT. Seven pigs tracheostomized, sedated and using neuromuscular blockade were submitted to mechanical ventilation. A recruitment maneuver (RM) using plateau pressure = 50cmH2O and positive end expiratory pressure (PEEP) = 35cmH2O for 2 minutes was applied. After, animals were ventilated in volume controlled ventilation mode (VCV), with a tidal volume (Vt) =10ml/kg, inspiratory flow=10l/min, respiratory frequency=10irpm, FiO2=100%. Decremental PEEP (20-10-3cmH2O) steps were applied with 10 minutes intervals between them. Thoracic computed tomography (CT) images were done with a continuous positive airway pressure (CPAP) = Plateau pressure achieved in VCV and PEEP applied, simulating an inspiration and expiration respectively. EIT was acquired continuously during the protocol. RM was repeated and then protocol was repeated, using FiO2=40%. Lung injury was induced (with lung lavage - SF 0.9% until SpO2< 95%). After protocol was repeated including both FiO2. Two TR detectors were tested; an original imaging tool created by our group (Method 1) and a second imaging tool created in a recent study by Putensen. (Method 2). Both methods were compared to CT. Results: A progressive...