Dräger Carina Instructions For Use Manual page 150

Principles of operation
The trigger window has a maximum duration of
5 seconds. For expiratory times shorter than
5 seconds, the trigger window covers the entire ex-
piratory time minus a refractory period of 500 ms to
the beginning of the expiration. The synchroniza-
tion of the mandatory breath reduces the expiratory
time.
The device extends the following expiratory time or
spontaneous breathing time by the missing time.
This prevents an increase of the mandatory res-
piratory rate. The number of mandatory breaths is
determined by the respiratory rate RR.
Pressure support
During spontaneous breathing on PEEP level, the
Δ
patient can be supported with Psupp. Every in-
spiratory effort of the patient on PEEP level that
meets the trigger criteria triggers a pressure-sup-
ported breath. By setting the trigger level, the pa-
tient's inspiratory efforts are synchronized. The
time, number, and duration of pressure-supported
breaths is determined by the patient's spontaneous
breathing.
As in all pressure-controlled ventilation modes, the
tidal volume supplied depends on the difference in
Δ
pressure Psupp, the lung mechanics (resistance
and compliance) and the patient's respiratory drive.
The pressure rise from the lower pressure level
PEEP to the upper pressure level Psupp is defined
with the Ramp setting.
The pressure support is terminated as soon as the
inspiratory flow falls below a specific proportion of
the maximum inspiratory flow.
The pressure support is also terminated as soon as
the duration of support exceeds a maximum inspir-
atory time Timax. The maximum inspiratory time is
limited to 130 % of Ti or a maximum of 4 seconds.
150 Instructions for use Carina SW 3.2n