Description
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Instructions for use Zeus Infinity Empowered SW 2.n
Ventilation
Flow measurement and volume delivery
Depending on the compliance of the lung to the
compliance of the breathing circuit, the volume sup-
plied by the ventilation device is distributed be-
tween the lung of the patient and the breathing cir-
cuit inserted between the device and the patient.
Deviations resulting for the delivered volume are
low for adult patients. This is due to their relatively
high lung compliance in relation to the much lower
compliance of the breathing hoses. Only the vol-
ume attained and surrendered by the lung is rele-
vant to the efficiency of ventilation. Larger differ-
ences are possible during pediatric ventilation.
Zeus IE basically compensates for the influence of
hose compliance to volume controlled ventilation.
Zeus IE ascertains the compliance of the breathing
hoses during the device check before ventilation.
Depending on airway pressure, Zeus IE increases
the tidal volume by the amount remaining in the
breathing hoses.
The expiratory minute volume and tidal volume are
measured with the aid of two internal flow sensors.
Measurement is adjusted for hose compliance. The
volume of the measured gas and the volume of the
delivered gas depend, however, on the ambient
conditions of temperature and pressure in the
breathing system. In lung physiology, the minute
volume and tidal volume are related to the condi-
tions in the lung: 37 °C body temperature, lung
pressure, 100 % rel. humidity (BTPS). The meas-
ured values for MV and VT calculated by Zeus IE
as well as the set point for VT always relate to
BTPS conditions. Leakages which occur at the pa-
tient end are taken into consideration by Zeus IE
neither during volume measurement nor during vol-
ume delivery.
Ventilation modes
Pressure Control (Pressure-controlled
ventilation)
This ventilation mode is identified as pressure-con-
trolled or time-controlled ventilation during which
the patient can always breathe spontaneously.
Pressure Control is thus often described as the
time-controlled change between two CPAP levels.
Controlled ventilation is achieved via the time-con-
trolled pressure change which corresponds to the
pressure-controlled ventilation (Pressure Control).
The constant possibility of spontaneous breathing
allows, however, a fluent transition of controlled
ventilation up to complete spontaneous breathing
without changing the ventilation mode. The
change-over from the expiratory pressure level to
the inspiratory pressure level and also the change
from the inspiratory pressure level to the expiratory
pressure level are synchronized with the patient's
spontaneous breathing. Good adaptation to the
spontaneous breathing behavior of the patient is
thus achieved.
The respiratory rate of changes is also kept con-
stant during synchronization via the "trigger win-
dow" with a fixed position in time.
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