Dead Space; Determining Cycle Time, Inspiratory Time And Expiratory Time - Dräger Oxylog 3000 plus Instructions For Use Manual

Description

Dead space

Dead space is an important aspect of ventilation
management:
Dead space is the portion of the breathing system
in which no significant gas exchange occurs. An
increase in the proportion of dead space to alveolar
ventilation may lead to increased CO
the patient.

Determining cycle time, inspiratory time and expiratory time

The basis for determining the cycle time (total time
for a respiratory cycle) during mandatory breaths is
the set respiratory rate (RR). This is complemented
with the set inspiratory time (Ti) or the set
ventilation time ratio (I:E).
NOTE
Values for Ti or I:E can be configured in the Cus-
tomer Service Mode, refer to "Customer Service
Mode" on page 97.
However, in case of conflicting settings the
ventilator will determine the cycle time, Ti and Te in
the following order:
– If the set time Ti is too short for the ventilator to
deliver the set tidal volume VT, the duration of Ti
is automatically increased. If the resulting Ti
exceeds the cycle time, the cycle time is
automatically increased. Note: This applies only
to volume-controlled ventilation modes.
– If the set time Ti exceeds the cycle time, the
duration of Ti is automatically adapted to the
cycle time.
– The expiratory time Te is at least 0.5 s. If the Te
no longer fits in the cycle time (owing to a long
Ti), the cycle time is automatically increased.
These rules are also applicable when the ventilator
is configured to set I:E instead of Ti.
160
Dead space is present as a component of the
patient's artificial airway and breathing circuit. If the
dead space volume corresponds to, or exceeds,
the volume of the alveolar ventilation, the patient
may possibly not exhale sufficient carbon dioxide. It
retention by is therefore important to take correct account of the
2
dead space volume in the breathing circuit of
Oxylog 3000 plus.
In case of conflicting settings, the alarm message !!
Check settings: time or !! Check settings: flow is
issued to notify the user to change the settings.
Instructions for use Oxylog 3000 plus SW 1.n