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REF 1057983 A Respironics V200 Ventilator Operator’s Manual 13-121
Chapter 13
Turning Auto-Trak Off 1. Touch either the I-Trigger or E-Trigger button in the Settings screen
(Figure 13-70). The I- Trigger or E-Trigger window will appear as
shown in Figure 13-73 or Figure 13-74.
2. Change the I-Trigger setting to Pressure or Flow, or change the E-
Trigger setting to %Peak Flow. (When you change the I-Trigger setting
to Pressure or Flow, the E- Trigger reverts to the most recently selected
%Peak Flow value. Similarly, when you change the E-Trigger setting to
%Peak Flow, the I-Trigger reverts to the most recently selected
Pressure or Flow value.)
3. Touch the Accept button in the I-Trigger or E-Trigger window. The
Settings screen will display the current I-Trigger and E-Trigger values
as shown in Figure 13-70.
Triggering and
Cycling with Auto-
Trak
In order to determine triggering and cycling sensitivity thresholds for each
breath, Auto-Trak applies multiple algorithms derived from flow, volume and
pressure measurements throughout the breathing cycle.
Triggering
Auto-Trak monitors changes in pressure and flow patterns throughout
exhalation, applies compensation for circuit leaks, and triggers an inspiration
when the criterion for one of the triggering algorithms has been met. As a
backup, Auto-Trak uses pressure triggering at a fixed level of 3 cm H
2
O.
Cycling
Auto-Trak automatically cycles breathing based on the pressure and flow
patterns at the end of inspiration and beginning of expiration. The threshold
used to cycle each breath changes with the patients breathing pattern and
lung dynamics.
Leak Detection and
Compensation
Patient leaks at the mask interface are a critical factor and are significant in
determining triggering and cycling thresholds. With noninvasive ventilation,
failure to compensate for these leaks can impact the patients work of
breathing.
Patient leak is the average leak rate during a breath and is estimated as the
delivered volume minus exhaled volume divided by the total breath time. This
average estimated leak value is displayed in LPM as Pt Leak in the Patient
Data section of the Settings screen. Pt Leak is updated with each breath.
Bias flow through the patient circuit is adjusted according to the estimated
leak and is quantified as follows: