Distribuição regional de gás e tecido na síndrome da angústia respiratória aguda: consequências do efeito da pressão expiratória final positiva
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Data
2007-02-02
Autores
Gusman, Pablo Braga [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Desde sua primeira descrição, muito se investiu no melhor conhecimento da SARA, na identificação de sua etiologia, seus fatores de risco, seus mecanismos e mediadores, escolhendo-se métodos críticos de avaliação clínica que também pudessem definir o prognóstico. Com o objetivo de verificar se os efeitos da PEEP dependem da morfologia pulmonar, comparando sua resposta em três grupos de pacientes, descritos de acordo com os aspectos de hiperdensidades observadas nos cortes tomográficos, foram estudados 71 pacientes portadores de SARA, comparando-os a 11 voluntários sadios. Cada paciente foi submetido a exame tomográfico helicoidal de tórax em ZEEP e após implemento de PEEP de 10 cmH2O. Parâmetros hemodinâmicos e respiratórios foram mensurados nas mesmas condições. Hiperdistensão induzida pela PEEP e recrutamento alveolar foram quantificados por um software específico, Lungview®. Hiperdistensão ocorreu somente nos lobos superiores e se correlacionou significativamente com volume pulmonar caracterizado por uma densidade tomográfica de parênquima pulmonar variando entre -900 UH e -800 UH em ZEEP. Efeitos cárdio-respiratórios em PEEP foram semelhantes nos pacientes com SARA primária e secundária. O recrutamento alveolar induzido pela PEEP nos lobos inferiores se correlacionou de forma significativa com seu volume pulmonar residual. Recrutamento alveolar induzido pela PEEP foi maior nos lobos inferiores com atelectasias inflamatórias do que nos lobos inferiores com atelectasias mecânicas. A morfologia pulmonar acessada pelo exame tomográfico influenciou de forma significativa os efeitos da PEEP. Em pacientes com hiperdensidades difusas, a PEEP induziu recrutamento alveolar importante sem hiperdistensão, enquanto que nos pacientes com hiperdensidades localizadas, a PEEP induziu...
There has been some decades, a lot has been invested in the attempt of better knowledge of ARDS, characterizing in a more trustworthy way your aetiology, risk factors, its mechanisms and mediators, choosing critical methods of clinical evaluation that could also foresee the prognostic. To determine whether differences in lung morphology assessed on the CT scan influence the response to PEEP we study by a prospective study during a 53-month period in a fourteenbed surgical Intensive Care Unit of a university hospital, seventy-one consecutive patients with early ARDS. In each patient, a fast spiral thoracic CT scan was performed in ZEEP and after implementation of PEEP 10 cmH2O. Hemodynamic and respiratory parameters were also measured in the same conditions. PEEPinduced overdistension and alveolar recruitment were quantified by a specifically designed software, Lungview®. Overdistension occurred only in the upper lobes and was significantly correlated with the volume of lung characterized by a scanographic density ranging between -900 HU and -800 HU parenchyma in ZEEP conditions. Cardiorespiratory effects of PEEP were similar in patients with primary and secondary ARDS. PEEP-induced alveolar recruitment of lower lobes was significantly correlated with their resting lung volume. PEEP-induced alveolar recruitment was greater in the lower lobes with inflammatory atelectasis than in the lower lobes with mechanical atelectasis. Lung morphology assessed on the CT scan markedly influenced the effects of PEEP: in patients with diffuse hyperdensities, PEEP induced a marked alveolar recruitment without overdistension whereas, in patients with lobar hyperdensities, PEEP induced a mild alveolar recruitment associated with overdistension of previously aerated lung areas. These results... (Complete abstract click eletronic address below)
There has been some decades, a lot has been invested in the attempt of better knowledge of ARDS, characterizing in a more trustworthy way your aetiology, risk factors, its mechanisms and mediators, choosing critical methods of clinical evaluation that could also foresee the prognostic. To determine whether differences in lung morphology assessed on the CT scan influence the response to PEEP we study by a prospective study during a 53-month period in a fourteenbed surgical Intensive Care Unit of a university hospital, seventy-one consecutive patients with early ARDS. In each patient, a fast spiral thoracic CT scan was performed in ZEEP and after implementation of PEEP 10 cmH2O. Hemodynamic and respiratory parameters were also measured in the same conditions. PEEPinduced overdistension and alveolar recruitment were quantified by a specifically designed software, Lungview®. Overdistension occurred only in the upper lobes and was significantly correlated with the volume of lung characterized by a scanographic density ranging between -900 HU and -800 HU parenchyma in ZEEP conditions. Cardiorespiratory effects of PEEP were similar in patients with primary and secondary ARDS. PEEP-induced alveolar recruitment of lower lobes was significantly correlated with their resting lung volume. PEEP-induced alveolar recruitment was greater in the lower lobes with inflammatory atelectasis than in the lower lobes with mechanical atelectasis. Lung morphology assessed on the CT scan markedly influenced the effects of PEEP: in patients with diffuse hyperdensities, PEEP induced a marked alveolar recruitment without overdistension whereas, in patients with lobar hyperdensities, PEEP induced a mild alveolar recruitment associated with overdistension of previously aerated lung areas. These results... (Complete abstract click eletronic address below)
Descrição
Palavras-chave
Anestesiologia, Sindrome do desconforto respiratorio, Acute respiratory distress syndrome, Positive end-expiratory pressure
Como citar
GUSMAN, Pablo Braga. Distribuição regional de gás e tecido na síndrome da angústia respiratória aguda: consequências do efeito da pressão expiratória final positiva. 2007. 92 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2007.