Origem física das curvas sigmoidais respiratórias pressão-volume: recrutamento alveolar e elasticidade não-linear

• Ano de defesa: 2011
• Autor(a) principal: Amaral, Ronaldo Alves do
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio Grande do Norte
• Programa de Pós-Graduação: Programa de Pós-Graduação em Ciências da Saúde
• Departamento: Ciências da Saúde
• País: BR
• Palavras-chave em Português: curvas sigmoidais respiratórias; recrutamento alveolar
• Palavras-chave em Inglês: lung; respiratory curves; sigmoidal alveolar recruitment
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE::MEDICINA
• Link de acesso: https://repositorio.ufrn.br/jspui/handle/123456789/13248

An important unsolved problem in medical science concerns the physical origin of the sigmoidal shape of pressure volume curves of healthy (and some unhealthy) lungs. Such difficulties are expected because the lung, which is the most important structure in the respiratory system, is extremely complex. Its rheological properties are unknown and seem to depend on phenomena occurring from the alveolar scale up to the thoracic scale. Conventional wisdom holds that linear response, i.e., Hooke s law, together with alveolar overdistention, play a dominant role in respiration, but such assumptions cannot explainthe crucial empirical sigmoidal shape of the curves. In this doctorate thesis, we propose an alternative theory to solve this problem, based on the alveolar recruitment together with the nonlinear elasticity of the alveoli. This theory suggests that recruitment may be the predominant factor shaping these curves in the entire range of pressures normally employed in experiments. The proposed model correctly predicts the observed sigmoidal pressure volume curves, allowing us to discuss adequately the importance of this result, as well as its implications for medical practice