Specifications

17Modes of Operation
In the T mode, the control panel settings determine all movement between the IPAP and EPAP levels.
When the interval timer triggers movement to IPAP, the electronic system immediately diverts flow to
the patient circuit to establish the IPAP level. The actual flow rate will be dependent upon the pressure
differential between the IPAP and EPAP levels and the combined resistance and compliance of the circuit
and the patient.
If the patient actively participates throughout the IPAP phase, the BiPAP S/T system responds as
necessary to satisfy the patient’s flow requirements while maintaining the preset pressure.
Under these conditions, patient effort, %IPAP, and the pressure differential determine the tidal volume. If
the patient does not actively participate, the BiPAP S/T system responds with the flow required to
maintain the preset pressure throughout the IPAP period. The delivered tidal volume will be dependent
upon the interaction of three components:
1. The combined resistance and compliance of the circuit and the patient.
2. The pressure differential between the IPAP and EPAP levels.
3. The length of time spent at the IPAP level as determined by the BPM and %IPAP settings.
Note: The patient may superimpose spontaneous respirations over the delivered IPAP or EPAP levels at
any point in the T mode. The BiPAP S/T system will respond with flow proportional to the patient’s
demand in order to maintain the preset pressure.
Warning: The BiPAP S/T system should not be applied to patients who are incapable of maintaining
life-sustaining ventilation in the event of a circuit disconnection or malposition of the
patient interface.
Warning: When operating this device in the Timed Mode with %IPAP values greater than 50%, time
spent at IPAP will exceed the time spent at EPAP (i.e., an inverse I:E ratio will be delivered). It is
important to monitor patient comfort level because increased inspiratory time exceeds the
decreased expiratory time.
Figure 6
V
P
est
5 cm H O
2
2 seconds
60 L/min.
2 seconds
60 L/min.
0
Example:
IPAP = 15 cm H
2
O
EPAP = 10 cm H
2
O
BPM = 10
%IPAP = 30
Figure 7
Example:
IPAP = 15 cm H
2
O
EPAP = 4 cm H
2
O
BPM = 12
%IPAP = 40
V
P
est
5 cm H O
2
2 seconds
60 L/min.
2 seconds
60 L/min.
0