Newport Breeze E150 - Pressure Limited Modes; With Peep

2.7.3 PRESSURE LIMITED MODES
The pressure limited modes
(a) Assist Control Mechanical Ventilation with Plateau
(AK
Plateau)
(b) Spontaneous Intermittent Mechanical Ventilation/ Plateau
(SIMV/ Plateau)
differ from one another in the same way as in the volume limited
mode. In the pressure limited modes each breath is limited in
inspiratory pressure by the peak inspiratory pressure (PIP) setting. The
PEEP/exhalation valve controls the expiratory drive line pressure
which limits the maximuminspiratory pressure. In the pressure limited
modes the path of main flow and spontaneous flow is similar to that of
the volume limited mode. Figure
2.5 and Figure 2.6 show the path of
gas flow in the inspiratory phase and expiratory phase respectively.
The operation of PEEP and PIP (Peak lnspiratory Pressure) in the
pressure limited modes is as follows:
With PEEP
In the inspiratory phase the PEEP solenoid receives an electrical
signal thereby supplying a pneumatic signal to the
PEEP/exhalation
valve which opens allowing gas to flow between the load (L) and supply
(S) ports. Air flows into the plateau regulator and the regulated output
flows through the plateau venturi assembly, and this generates the
control pressure which flows into the PEEP plateau assembly. This
gas flows out of the
PEEP/Exhalation valve into the expiratory drive
line building up a pressure which depends on the plateau (PIP)
regulator setting. The main flow at this time flows into the breathing
circuit where it is confined by the exhalation valve. When the pressure
of the gas in the breathing circuit exceeds that of the expiratory drive
line pressure the exhalation valve opens up partially to bleed off the
excess gas and thereby maintains the Peak lnspiratory Pressure (PIP).