MATHEMATICAL MODELLING OF NON-INVASIVE PRESSURE SUPPORT VENTILATION: INVESTIGATION OF TIDAL VOLUME INSTABILITY - Quantitative Medical Data Analysis Using Mathematical Tools and Statistical Techniques - page 292

a

H a L

Unstable flow cutoff values
Psen = 5, R = 20, f = 14

1

0.8

0.6

0.43

0.4

0.33

0.22

0.35

0.2 0.26

0.18

0.1
0 . 07

0. 0 9

0. 0 5

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

0.65

0.57

0.6

0.46 0.52

0.4 0.45

0.30

0.31

0.36

0.21

0.21

0.2

0.24

0.11

0.14

0.11
0.08

0.08

0.06

C

0.04 0.06 0.08 0.1 0.12 0.14

Fig. 5. Unstable ow cut-o values: C = 0:06, 0:08, 0:10 and 0:12 L/cmH 2 O,
R i = R e = 20 cmH 2 O/L/s, P set = 22 cmH 2 O, P peep = 5 cmH 2 O, t tot = 6
s, P sen = 5 cmH 2 O, (a) f = 14 breaths/minute; (b) f = 22 breaths/minute.
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.