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Conclusions and future developments
Conclusions and future developments
The measurement of respiratory mechanics is essential in intensive care respiratory
medicine. Nevertheless, the respiratory mechanism is rarely measured in the ventilatordependent
patients to the belief that these measures are even more difficult to obtain and to
interpret and unreliable, especially in the case of high-frequency percussive ventilation, on
which there are few studies .
In this work the basis of the characterization of high-frequency percussive ventilator were
laid, identifying the characteristics of elastic and resistive load.
The ventilation conditions currently used in medicine mostly include the adjustment of the
frequency of percussion and pressure peak, and then the work has been addressed towards the
analysis of these variables, proving to be adequate to justify the positive results obtained in
intensive care, in the treatment of patients with certain respiratory problems.
An important result is the possibility of obtaining estimates of respiratory parameters
which, within acceptable limits of error, provide the evolutionary trend of respiratorymechanical
characteristics of a patient independently of the frequency of percussion.
Therefore, it is not necessary to replace the percussive ventilator with a conventional for the
measure of those parameters. This allow to follow the temporal evolution of the resistive and
viscoelastic conditions, the latter particularly dependent upon removal of bronchial secretions.
The high-frequency percussive ventilation combines together two complementary
mechanisms: the high oscillation frequency (diffusive behavior) and pressure controlled
ventilation (convective behavior). The prevalence of either depends on the mechanical
impedance characteristics, but their combined action leads to a sufficient exchange of
pulmonary gases in patient and in all situations.
From the obtained results we can deduce that the VDR-4 is a versatile ventilator which
provides adequate ventilation at all load conditions, as a result of the use of a Venturi type
device, which allows the patient to enter at any stage of ventilation with his spontaneous
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