Free Breathing Valve; Breathing Circuit Flow Sensors - Datex-Ohmeda S/5 Avance Technical Reference Manual

S/5 Avance
2.12.9 Free
breathing valve
2.12.10 Breathing
circuit flow
sensors
2-40
The free breathing valve (17) helps assure the patient can spontaneously breathe. The
ventilator is programmed to supply a specified number of breaths per minute to the
patient. If, in between one of these programmed cycles, the patient needs a breath
(spontaneous), the free breathing valve permits the patient to inhale. The free
breathing valve is closed on mechanical inspiration.
Figure 2-42 • Free breathing valve
Two flow sensors are used to monitor inspiratory and expiratory gas flow. The
inspiratory flow sensor is downstream of the gas system inspiratory check valve.
Feedback from the inspiratory transducer is used to supply tidal volumes that make
allowances for the effects of fresh gas flow and circuit compressibility. The expiratory
flow sensor is located at the input to the gas system expiratory check valve. Feedback
from the expiratory flow sensor is used to supply signals for expiratory tidal volume
monitoring and the breath rate.
P
Ventilator Interface Board
Figure 2-43 • Flow sensors
17
rnate O2
ble Valve
Expiratory
Gas Monitor
Flow Sensor
Inspiratory
Flow Sensor
P P P
Vent Engine
Atmosphere
Free Breathing
Check Valve
Popoff
Valve
Mechanical Over Pressure
Valve (110 cm H2O)
Exhalati
Drive Gas Check Valve
(2.0 cm
(3.5 cm H2O bias)
Inspiratory Flow
Control Valve
20
25 psig @
15 LPM
Gas Inlet
Valve
Co
if
11/03 1009-0357-000