Annals of biomedical engineering
-
Comparative Study Clinical Trial
Symbolic dynamic analysis of relations between cardiac and breathing cycles in patients on weaning trials.
Traditional time-domain techniques of data analysis are often not sufficient to characterize the complex dynamics of the cardiorespiratory interdependencies during the weaning trials. In this paper, the interactions between the heart rate (HR) and the breathing rate (BR) were studied using joint symbolic dynamic analysis. A total of 133 patients on weaning trials from mechanical ventilation were analyzed: 94 patients with successful weaning (group S) and 39 patients that failed to maintain spontaneous breathing (group F). ⋯ The histogram of the occurrence probability of the cardiorespiratory words presented a higher homogeneity in group F than in group S, measured with a higher number of forbidden words in group S as well as a higher number of words whose probability of occurrence is higher than a probability threshold in group S. The discriminant analysis revealed the best results when applying symbolic dynamic variables. Therefore, we hypothesize that joint symbolic dynamic analysis provides enhanced information about different interactions between HR and BR, when comparing patients with successful weaning and patients that failed to maintain spontaneous breathing in the weaning procedure.
-
Relationships between nerve root compression, behavioral sensitivity, spinal cytokines, and glial reactivity are not fully defined for painful cervical nerve root compression. Spinal cytokines were quantified after mechanical root compression (10gf), root exposure to inflammatory chromic gut material (chr), the combination of both insults together (10gf + chr) or sham. TNFalpha and IL-1beta significantly increased at 1 h (p < 0.029). ⋯ Sensitivity remained significantly elevated over sham at all time points (p < 0.044). Spinal astrocytic reactivity significantly decreased for both treatments after 10gf (p < 0.002); but, only IL-1ra following 10gf + chr significantly reduced astrocytic reactivity (p < 0.001). Early increases in spinal TNFalpha, IL-1beta, and IL-1alpha may induce pain, affect spinal astrocytic responses, and appear to have differential effects in mediating the behavioral hypersensitivity produced by different types of painful cervical radicular injuries.