Newport Breeze E150 - With no Peep

In the expiratory phase the PEEP solenoid is closed and therefore the
PEEP/Exhalation valve is in the normally closed condition. It allows
flow through the Exhaust and Load ports. The gas from the PEEP
regulator flows into the
PEEP/Exhalation valve through its venturi
assembly. The excess gas is bled off from the venturi assembly. An
increase or decrease in the expiratory drive line pressure is obtained
by adjusting the PEEP pressure regulator. This results in a similar
change in the exhalation valve, and thus the PEEP pressure.
WITH NO PEEP
With PEEP off (i.e. set at zero) the opening and closing of the valves
and solenoid is similar to the case with PEEP on. Since there is no
flow out of the PEEP regulator, there is no flow into the PEEP venturi
assembly or into the
PEEP/Exhalation valve, so at end of the
inspiration cycle the gas in the expiratory drive line bleeds out of the
PEEP venturi base assembly dropping the pressure in the expiratory
drive line to
0 cmH20 and subsequently the exhalation valve opens
allowing the patient to exhale. This in turn results in a drop in pressure
in the breathing circuit and lung to zero.