Modelo computacional de hiperinsuflação em pulmões com padrão obstrutivo ao fluxo aéreo
Computational model of hyperinflation in lungs with airflow obstruction pattern
Kelser de Souza Kock, Estevan Grosch Tavares, Daniela Ota Hisayasu Suzuki
Resumo
Introdução: A modelagem matemática é uma técnica que utiliza pressupostos teóricos e simulação computacional para compreensão e predição de dados experimentais. Objetivo: modelar matematicamente, por meio de simulação computacional, o mecanismo de hiperinsuflação durante a respiração espontânea em pulmões com padrão obstrutivo ao fluxo aéreo através de variáveis relacionadas à mecânica respiratória: complacência e resistência do sistema respiratório. Métodos: Para construção do modelo foi realizado cálculo numérico através da equação do movimento, considerando-se que na fase inspiratória a pressão varia senoidalmente e na fase expiratória a pressão é nula. O ciclo respiratório foi simulado durante 20 segundos em 4 casos: eupneia e taquipneia em pulmão hígido, eupneia e taquipneia em pulmão com padrão obstrutivo ao fluxo aéreo. Resultados: os valores de volume expiratório final aproximaram-se de 0,0006, 0,0181, 0,0562 e 0,2145 litros, para os 4 casos, respectivamente, conforme simulação. Conclusão: A implementação deste modelo computacional demonstrou que variáveis de mecânica respiratória podem ser utilizadas para predizer o aprisionamento aéreo.
Palavras-chave
Abstract
Introduction: Mathematical modelling is a technique that uses theoretical assumptions and computer simulation to understand and predict experimental data. Objective: The objective of this study was to model mathematically, through computer simulation, the hyperinflation mechanism during spontaneous breathing in lungs with an airway obstruction pattern, using the following variables related to respiratory mechanics: compliance and resistance of the respiratory system. Methods: The model was built with numerical calculation using the equation of motion. During the inspiratory phase, the pressure variation was considered to be sinusoidal, whereas in the expiratory phase the pressure was considered to be zero. The respiratory cycle was simulated for 20 seconds in 4 different scenarios: eupnea and tachypnea in a healthy lung; eupnea and tachypnea in a lung with an airway obstruction pattern. Results: The values of end-expiratory lung volume approached 0.0006, 0.0181, 0.0562 and 0.2145 liters, for the 4 scenarios, respectively, as simulated. Conclusion: The implementation of this computational model demonstrated that mechanical respiratory variables can be used to predict air trapping.
Keywords
Referências
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