Heyer iTernIS ADV, Operator'S Manual

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Respiratory mechanics | iTernIS ADV
12. 4
Fig. 12-1 Auto-PEEP test window appearance. The white
arrow is used to indicate the start of the test (expiratory
pause).
Compliance of the respiratory system is one of the variables most commonly mea-
sured during mechanical ventilation. This maneuver determines static and dynamic
compliance.
Inspiratory and expiratory resistances are defined as the difference in pressure
required to generate a set inspiratory or expiratory flow, and they are the expres
-
sion of resistance to flow opposed by the airways (from the patient, artificial, and
ventilator circuit).
Compliance and resistance tests are performed in the same maneuver.
Dynamic compliance is calculated according to the change in pressure that occurs
during the insufflation of a known volume according to the following formula:
VT
Dynamic Compliance =
P
max
- PEEP
Dynamic Compliance is a global index that refers to the patient’s respiratory impe-
dance in general, without distinction of its elastic and resistive components.
In this ventilator, dynamic compliance is shown in real time, breath by breath, in the
screen corresponding to
PATIENT’S DATA
(see
Menu
) chapter.
Static Compliance is equal to the pressure change required to produce a change in
volume (dV/dP). This ventilator calculates it as follows:
VT
Static Compliance =
P
plateau
- PEEP
TOTAL
The calculation takes into account the compliance of the ventilator circuit. Both
the compliance and resistance are parameters of respiratory mechanics that are
closely linked with the pulmonary volume for which they were measured. This is
12.2 | Compliance and
Resistance
12.2.1 | Concepts
12.2.1.1 | Dynamic Compliance
12.2.1.2 | Static compliance