Biomedical Engineering Reference
In-Depth Information
10.2 Important Directions for Research
10.2.1 Relating the Fractional Order Parameter Values
to Pathology
It is significant to recognize the importance of relating the fractional order model
parameter values to the specific changes occurring in lung pathology. Since these
fractional orders are related to the physiology of the lungs, they give insight in the
changes occurring in the structure and morphology of the airways with the gradual
changes in the disease.
For instance, it has been shown that the fractional order arises from the recur-
rence ratio of the resistance and compliance per level. Most of the obstructive and
restrictive lung disorders have a crucial impact on the overall resistance and com-
pliance of the lungs, hence it is clear that changes in these properties will lead to
changes in the values obtained for the fractional orders.
10.2.2 Low Frequency Measurements
In this topic, a broad range of frequencies have been covered in terms of respiratory
impedance. However, the most interesting for analysis of changes in the tissue with
disease evolution is the 0.1-1 Hz frequency band. Therefore, one needs to mea-
sure closer to the breathing frequency. This will then bias the estimates due to the
high noise level coming from the breathing signal itself. Hence, an interesting re-
search direction is that of improving the low frequency identification presented in
this topic, in the presence of nonlinear distortions coming from the breathing of the
patient. This can be achieved by developing adaptive filtering methods for cancel-
ing non-stationary effects from the breathing of the individual under test. Eventually,
changes in the device components and setup may also be beneficial for improving
the overall performance.
