High-Frequency Ventilation- Basics and Practical Applications

Strategies for HFV
To this end, lower pO 2 values and higher pCO 2 values often have to
be accepted. Do not superimpose IMV for the risk of baro trauma.
Place the infant on the side of the air leak. Adjust MAP below that of
the conventional ventilation if possible. Choose a low HFV frequency.
The further strategy heads above all for a reduction in pressure. If
successful, continue HFO another 24 to 48 hours until the radiologic
signs of the airleak have clearly subsided [2, 24, 29].
8.4 HFV for atelectases
HFV with air leaks
Goal: improved oxygenation and ventilation at minimum MAP;
(accept lower pO 2 and higher pCO 2 )
– Do not superimpose IMV!
– Begin with MAP like or below that of conventional ventilation
– HFV frequency low, for example, 7 Hz
– Reduce pressure prior to FiO 2
– Continue HFV for 24 to 48 hours after improvement
Even under conventional ventilation, especially in the presence of
pneumonia, meconium aspiration, or BPD, stubborn atelectases
often develop. According to our experience intermittent oscillatory
ventilation can resolve such atelectases. About six times a day before
suctioning we apply HFV for some 15 to 30 minutes. With slightly
raised PEEP, the IMV can continue, however, the rate should not
exceed 20 bpm to ensure enough time for oscillations. After the suctioning
we switch HFO off again. The effect on opening the atelectases
is possibly based on ‘inner vibration’, elevated inflation
through raised MAP, and increased mucociliar clearance [62, 71, 93].
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