Philips Respironics V60, User Manual

Page: 82 / 212

6-8
Operation
Figure 6-1: PPV waveform – Max V limit
When the Max P (PPV maximum pressure limit) is reached, pressure is limited
but the breath is not terminated, and a message is displayed. After the limit is
reached in three consecutive breaths, the audible alarm sounds. A PPV
waveform with Max P is shown in Figure 6-2.
Figure 6-2: PPV waveform – Max P limit
Frequent annunciation of one or both alarms typically indicates improved
patient status. It may, however, indicate that the patient is more actively
breathing, possibly due to agitation or a change in the patient’s level of
sedation. It may also indicate an increase in leakage.
The V
T
(estimated exhaled tidal volume) measurement may remain below the
set Max V limit even though the inspired volume exceeds Max V. This results
from variable leakage, which reduces the exhaled volume in relation to the
inspired volume.
Vol
u
me
Fl
o
w
Max V
V
T

Max V
Inspiration terminated
Sudden increase
in flow
Time
Pressure
EPAP
Max P
Sudden increase
in target pressure
Pressure limited Exhalation cycled by patient