study of multiparameter respiratory pattern complexity in surgical critically ill patients during weaning trials研究多参数在外科危重病人呼吸模式复杂性断奶试验.pdf

Papaioannou et al. BMC Physiology 2011, 11:2 /1472-6793/11/2 RESEARCH ARTICLE Open Access Study of multiparameter respiratory pattern complexity in surgical critically ill patients during weaning trials 1*† 2† 2 1 Vasilios E Papaioannou , Ioanna G Chouvarda , Nikos K Maglaveras , Ioannis A Pneumatikos Abstract Background: Separation from mechanical ventilation is a difficult task, whereas conventional predictive indices have not been proven accurate enough, so far. A few studies have explored changes of breathing pattern variability for weaning outcome prediction, with conflicting results. In this study, we tried to assess respiratory complexity during weaning trials, using different non-linear methods derived from theory of complex systems, in a cohort of surgical critically ill patients. Results: Thirty two patients were enrolled in the study. There were 22 who passed and 10 who failed a weaning trial. Tidal volume and mean inspiratory flow were analyzed for 10 minutes during two phases: 1. pressure support (PS) ventilation (15-20 cm H O) and 2. weaning trials with PS: 5 cm H O. Sample entropy (SampEn), detrended 2 2 fluctuation analysis (DFA) exponent, fractal dimension (FD) and largest lyapunov exponents (LLE) of the two respiratory parameters were computed in all patients and during the two phases of PS. Weaning failure patients exhibited significantly decreased respiratory pattern complexity, reflected in reduced sample entropy and lyapunov exponents and increased DFA exponents of respiratory flow time series, compared to weaning success subjects (p 0.001). In addition, their changes were opposite between t