Heyer iTernIS ADV, Operator'S Manual

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Respiratory mechanics | iTernIS ADV
12. 10
Changes in pulmonary mechanics that occur in acute respiratory failure can be mo-
nitored by serial measurement of the inflection points in the Pressure/Volume cur -
ve. The method used by the
iTernIS ADV
ventilator for this analysis, is pulmonary
insufflation with low flow. Thus, it is possible to determine the lower inflection point
(Lip) and upper inflection point (Uip). The data provided by the first one is used to
assist in determining the optimal PEEP level, able to prevent alveolar collapse or
injury by the opening and subsequent closure of the alveoli (atelectrauma).
The Uip represents the transition to pulmonary overdistension, indicating the maxi-
mum usable pressure and volume limit during pulmonary ventilation.
As additional data, during this maneuver, the value of pulmonary compliance can
also be obtained from the middle section of the curve (Cmax).
This test is only enabled for the ADL and PED patient categories.
The patient must be intubated, and without exerting inspiratory efforts during the
test.
The ventilator injects a low flow into the patient and monitors the pressure behavior
of the respiratory system in relation to the entered amounts. The inflection points
are located at the site of the curve where the slope changes (changes in the system
compliance).
Each measuring maneuver has the following sequence of steps:
• Expiration of 3 s with PEEP = 0 cmH
2
O.
• Start of pulmonary disinflation, with low oxygen flow (100%).
• Start of the curve plotting, until the end of the test.
• The maneuver ends when the maximum pre-regulated pressure or volume is rea -
ched (whichever occurs first; see 12.6.3 Implementation).
• Ventilation is resumed with the operative mode and values existing prior to the
start of the test.
• The numerical data window shows the results of the measurement.
Test enabled in the following modes:
• VCV
• PCV
• PRVC
12.6 | PV flex (Puntos de
Inflexión)
12.6.1 | Concepts
12.6.2 | Procedure