ResMed Elisee 350 Clinical Manual page 94

The pressurised air assembly also contains integrated sensors to monitor ventilation:
Sensors
Proximal pressure sensor (Paw)
Proximal pressure sensor for pressure triggering (Ptg). This sensor is more precise than the Paw
sensor. It measures negative pressure values and patient effort
Expiratory flow sensor (for monitoring exhaled air in double circuits),
Inspiratory flow sensor for monitoring inhaled air,
Safety turbine outlet pressure sensor (Pout)
Chemical sensor measuring external FiO
Oxygen pressure sensor for the pressure regulator outlet, PO
Safety chemical sensor for measuring O
Atmospheric pressure sensor, Patm
Temperature sensor
Hall-effect turbine speed sensor
How the ventilator works
•
Outside air is sucked in through a dust filter.
•
It may be enriched with oxygen using the low-pressure oxygen port (400 kPa max., 15 L/min
max.) or the high-pressure oxygen port (240–700 kPa max.). The FiO
dedicated chemical sensor. At first, the high-pressure oxygen is released at 190 kPa
maximum: a pressure sensor measures the presence and pressure of oxygen. Then a
proportional solenoid valve regulates the flow of oxygen injected into the turbine. This oxygen
pressure can also be used, via a solenoid valve, to control a nebuliser.
•
The turbine then compresses the oxygen/air mixture. The turbine enables closed-loop control
of the required pressures and flow rates. The turbine speed is regulated by the
microprocessor on the basis of the set parameters. It is controlled either by the inspiratory
flow sensor in volume-based modes, or by the proximal pressure sensor in pressure-based
modes.
•
At the turbine outlet, a rotary valve controlled by a stepper motor controls the level and shape
of air pressure and flow with precision.
•
An I/E solenoid valve controls the expiratory valve, which in turn controls the inspiratory and
expiratory times.
•
There is also a microturbine which can generate a counter-pressure during the expiratory
phase to maintain the level of PEEP .
•
A sensor dedicated to triggering complements the proximal pressure sensor in detecting
patient effort.
•
For safety reasons, an inspiratory valve allows the patient to breathe spontaneously
regardless of the status of the ventilator.
•
The solenoid valves dedicated to cleaning remove humidity from the double circuit support to
improve expiratory spirometry.
•
The P0.1 electromagnet creates a total obstruction of the circuit so that the patient effort can
be measured.
•
An atmospheric pressure sensor corrects the measurements recorded by the other sensors.
•
A temperature sensor monitors increases in internal temperature, and controls the cooling
fans.
•
Two solenoid valves (auto offset) enable automatic recalibration of the inspiratory flow sensor
offset.
Note: Only the high-pressure oxygen port provides control of the oxygen concentration.
88/102
°
e
°
i
2
2
concentration, O S (leak)
2 2
Measurement range
0–100 cm H O
2
-10 cm H O – +40 cm H O
2 2
0–180 L/min
0–180 L/min
0–100 cm H O
2
0–100%
0–700 kPa
0–100%
15–115 kPa
-15°C – +90°C
0–65,000 rpm
is monitored using a
2
NOT013281-8