1. The bird IPPB machine The Bird is pneumatically powered & controlled.
it can be triggered [1] by negative pressure [2] by time or [3] manually.
It is pressure limited, changing the breath as pressures rise
It is pressure or time-cycled off

2. Gas inlet
From 50 psig
Ambient
chamber
Pressure
chamber
Sensitivity
control
Pressure
control
Nebulizer
drive line
Main flow
drive line

3. A flow rate control
B ceramic switch
C restricted orifice for entrainment
D nebulizer drive line to in-line SVN
E exhalation valve [mushroom valve]

4. On the right side of the screen see the PRESSURE CHAMBER,
left
This is a simplified picture of the ceramic switch and what makes it move to start or end a breath.
On the left side of the screen is the AMBIENT CHAMBER [see the hole toward the outside?]
On the right side of the screen see the PRESSURE CHAMBER,
[see the outlet going to the patient circuit?]
In A you see that the diaphragm is mid-line, the ceramic switch is closed. No air moves

5. In both the AMBIENT CHAMBER and in the PRESSURE CHAMBER, there is no extra pressure, both chambers are at zero [ 1 atmosphere]. There is no gas flow and the ceramic switch is closed.

6. This negative pressure pulls the clutch plate toward the magnet in the PRESSURE CHAMBER & when it gets close enough, the magnet pulls the clutch plate closer.
The diaphragm moves toward the patient, to open the ceramic switch.
Gas flows into the PRESSURE CHAMBER, into the circuit and into the patient’s lungs.

7. In C, the diaphragm stays toward the magnet
As long as the pressure in the PRESSURE CHAMBER is lower
Than the magnet force in the AMBIENT CHAMBER …the breath continues
We can control how deep a breath the patient takes by altering the positive pressure needed to overcome the magnet that will stop the breath

8. As the patient’s lung fills with gas, the pressure builds up in the lung, then in the circuit and finally in the PRESSURE CHAMBER
Once high enough, the positive pressure in the PRESSURE CHAMBER pushed the diaphragm toward the AMBIENT CHAMBER and flow stops--- the breath has stopped.

9. On exhalation: the ceramic
switch is closed, gas stops
flowing and the patient exhales
into the exhalation valve
On inspiration
ceramic switch is
open, gas flows to
the patient whose lung
fill

10. On inspiration, the gas flows from the
top into the Pressure chamber, into
the circuit.
At the same time, the exhalation
valve is closed by the same pressure
As long as there is pressure building
up in the pressure chamber, the
exhalation valve is closed.
Gas can move only into the lung

11. On exhalation phase: the pressure drops in the pressure chamber and the exhalation valve is open to the atmosphere so that the patient exhales
into the atmosphere
The ceramic switch is closed
and there Is no gas flow into any chamber.

12. During inspiration, 02 from the ceramic switch moves into the
Air mix: entrainment devices
During inspiration, 02 from the
ceramic switch moves into the
line that powers the entrainment
device.
The flow goes through
the restricted orifice decreasing lateral
wall pressure in the ambient chamber
so that it pulls air from the
ambient chamber into the gas flow
going to the pressure chamber.
What do you suppose happens to
the Fi02 and to the total flow down
the main flow drive line as the pressure
rises inside the pressure chamber?