Theory of operation
Puritan Bennett™ 700 Series Ventilator System Service Manual
10070389 Rev. A
2-67
2.6.2 Breath triggering
On the 700 Series
Ventilator System, breaths can be ventilator-initiated, operator-initiated,
and patient-initiated (see Figure 2-56):
• A
ventilator-initiated breath
is triggered at an interval based on the RESPIRATORY RATE
setting.
• An
operator-initiated breath
is triggered in response to the MANUAL INSPIRATION key
being pressed.
• A
patient-initiated
breath is triggered when the ventilator senses patient effort. As shown
in Figure 2-57, when patient effort begins, the exhalation pressure transducer measures a
drop in pressure (P
e
). As a result, the piston, which is constantly moving forward to
maintain PEEP, speeds up to compensate for the pressure drop. When the piston velocity
to maintain PEEP exceeds the operator-selected TRIGGER SENSITIVITY flow value (3 L/min
in this case), the ventilator triggers into inspiration.
When a breath is triggered, the exhalation solenoid is energized, which causes the exhalation
valve to be piloted closed.
Summary of Contents for Puritan Bennett 700 Series
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