MATHEMATICAL MODELLING OF NON-INVASIVE PRESSURE SUPPORT VENTILATION: INVESTIGATION OF TIDAL VOLUME INSTABILITY - Quantitative Medical Data Analysis Using Mathematical Tools and Statistical Techniques - page 293

a

H a L

Unstable flow cutoff values
Psen = 5, R = 15, f = 14

1

0.8

0.6

Stable

0.4

0.27
0.22

0.18

0.2

0.15

0.09

C

0.04 0.06 0.08 0.1 0.12 0.14

a

H b L

Unstable flow cutoff values
Psen = 5, R = 20, f = 22

1

0.8

0.6

0.55

0.41

0.43

0.4

0.33

0.35

0.18

0.26

0.2

0.19

0.11
0.0 8

0.13

0.15

0. 0 5

0.05

C

0.04 0.06 0.08 0.1 0.12 0.14

Fig. 6. Unstable ow cut-o values: C = 0:06, 0:08, 0:10 and 0:12 L/cmH 2 O,
P set = 22 cmH 2 O, P peep = 5 cmH 2 O, t tot = 6 s, f = 14 breaths/min, P sen = 5
cmH 2 O, (a) R i = R e = 15 cmH 2 O/L/second; (b) R i = R e = 25 cmH 2 O/L/s.
The diamonds () indicate unstable ow cut-o region in which t tot changes
from t tot = 60=f to t tot = 120=f. The boxes () indicate unstable ow
cut-o region in which t tot changes from t tot = 120=f to t tot = 180=f. The
triangles (NN) indicate unstable ow cut-o region in which t tot changes from
t tot = 180=f to t tot = 240=f.