Philips Respironics V60, User Manual

Page: 46 / 212

4-2
Principles of operation
Pneumatic system
operation
The ventilator uses ambient air and high-pressure oxygen (Figure 4-1). Air
enters through an inlet filter. Oxygen enters though a high-pressure inlet, and a
proportioning valve provides the operator-set concentration. The system mixes
the air and oxygen, pressurizes it in the blower, and then regulates it to the
user-set pressure. To do this, the ventilator compares the proximal (patient)
pressure measurement with the ventilator outlet (machine) pressure, and
adjusts the machine pressure to compensate for the pressure drop across the
inspiratory filter, patient circuit, and humidifier. This helps ensure accurate
and responsive pressure delivery and leak compensation.
Figure 4-1: Respironics V60/V60 Plus Ventilator gas delivery system
The ventilator delivers gas to the patient through a main flow (inspiratory)
bacteria filter, a single-limb patient breathing circuit, a humidification device
(optional) and a patient interface such as a mask or ET tube. A pressure tap
proximal to the patient is used to monitor patient pressure. The exhalation port
continually exhausts gas from the circuit during inspiration and exhalation to
minimize rebreathing and ensure CO
2
removal.
Breath delivery
characteristics
Control variable
Breaths delivered by the Respironics V60/V60 Plus Ventilator are pressure
controlled. In the AVAPS mode, the ventilator’s applied pressure is
automatically adjusted over a period of time to maintain a target tidal volume.
Triggering, cycling, and leak adaptation
Unlike other ventilators, the Respironics V60/V60 Plus Ventilator does not
require you to set triggering and cycling sensitivity or to adjust baseline
flow.The ventilator’s unique Auto-Trak Sensitivity algorithm adjusts these
automatically; see “Auto-Trak Sensitivity” on page 4-3.
Baseline pressure
A positive baseline pressure (EPAP or CPAP) may be set for all breaths in all modes.
Respironics V60/V60 Plus Ventilator
Blower
High-
pressure
oxygen
Ambient
air
Proximal (patient)
pressure
Ventilator outlet
(machine)
pressure
Air flow
sensor
Mixer
Propor-
tioning
valve
O
2
flow
sensor
Air inlet
filter
Main flow
filter
Patient
Exhalation
port
O
2
pressure