4-10
Principles of operation
S/T mode
The S/T (spontaneous/timed) mode guarantees breath delivery at the user-set
rate. It delivers pressure-controlled, time-cycled mandatory and pressure-
supported spontaneous breaths, all at the IPAP pressure level. If the patient
fails to trigger a breath within the interval determined by the Rate setting, the
ventilator triggers a mandatory breath with the set I-Time. The patient triggers
and cycles based on the ventilator’s Auto-Trak Sensitivity algorithms. The
control settings active in the S/T mode are shown in Figure 4-10. Figure 4-11
shows an S/T mode pressure waveform.
Figure 4-10: S/T controls
Figure 4-11: S/T pressure waveform
Pressure
EPAP
IPAP
I-Time
1/Rate
Patient-triggered (Spont)
spontaneous breath with
pressure support
Mandatory
(Timed) breath
Time
Rise