UVM Theses and Dissertations
We then fitted a resistance-elastance-inertance model of the lung to each data set. For non-asthmatic subjects, the average resistance (R) and elastance (E) values for the first spontaneous breathing trial were 2.5±0.15 cmH₂O.s.m1⁻¹ and l8.1±3.55 cmH₂O.s.m1⁻¹, and for the third spontaneous breathing trial were 2.4 ±0.12 cmH₂O.s.m1⁻¹ and 21.8±4 cmH₂O.s.m1⁻¹. R and E for the first tracked breathing trial were 2.3±0.21 2.3±0.21 cmH₂O.s.m1⁻¹ and 33.6±7.4 cmH₂O.s.m1⁻¹, and for the third tracked breathing trial were 2.4±0.14 cmH₂O.s.m1⁻¹ and 25.75±4.3 cmH₂O.s.m1⁻¹, respectively.
For asthmatic subjects, the average Rand E values for the first spontaneous breathing trial were 3.32±0.68 cmH₂O.s.m1⁻¹ and 39.13±9.8 cmH₂O.s.m1⁻¹, and for the third spontaneous breathing trial were 3.12±0.15 cmH₂O.s.m1⁻¹ and 39.91±6.2 cmH₂O.s.m1⁻¹. R and E for the first tracked breathing trial were 2.86±0.15 cmH₂O.s.m1⁻¹ and 32.47±4.1 cmH₂O.s.m1⁻¹, and for the third tracked breathing trial were 2.86±0.2l cmH₂O.s.m1⁻¹ and 33.89±10 cmH₂O.s.m1⁻¹, respectively.
These results show that R was consistently lower during tracked breathing than spontaneous breathing in both non-asthmatic and asthmatic subjects. However, an increase in E was observed during tracked breathing. We suspect this effect may have resulted from dynamic hyperinflation. These results also show that R and E are reproducible with both spontaneous and tracked breathing, and that R and E were not noticeably different between both breathing maneuvers. We conclude that using biofeedback to control the breathing pattern during application of the FOT in normal subjects does not significantly affect impedance measurements, and thus may be useful for avoiding spectral overlap between FOT perturbations and the breathing pattern.