Tingay, DG and John, J and Harcourt, ER and Black, D and Dargaville, PA and Mills, JF and Davis, PG, Are All Oscillators Created Equal? In vitro Performance Characteristics of Eight High-Frequency Oscillatory Ventilators, Neonatology, 108, (3) pp. 220-228. ISSN 1661-7800 (2015) [Refereed Article]
© 2015 S. Karger AG
Background: The mode of waveform generation and circuit characteristics differ between high-frequency oscillators. It is unknown if this influences performance.
Objectives: To describe the relationships between set and delivered pressure amplitude (ΔP), and the interaction with frequency and endotracheal tube (ETT) diameter, in eight high-frequency oscillators.
Methods: Oscillators were evaluated using a 70-ml test lung at 1.0 and 2.0 ml/cm H2O compliance, with mean airway pressures (PAW) of 10 and 20 cm H2O, frequencies of 5, 10 and 15 Hz, and an ETT diameter of 2.5 and 3.5 mm. At each permutation of PAW, frequency and ETT, the set ΔP was sequentially increased from 15 to 50 cm H2O, or from 20 to 100% maximum amplitude (10% increments) depending on the oscillator design. The ΔP at the ventilator (ΔPVENT), airway opening (ΔPAO) and within the test lung (ΔPTRACH), and tidal volume (VT) at the airway opening were determined at each set ΔP.
Results: IIn two oscillators the relationships between set and delivered ΔP were non-linear, with a plateau in ΔP thresholds noted at all frequencies (Dräger Babylog 8000) or ≥10 Hz (Dräger VN500). In all other devices there was a linear relationship between ΔPVENT, ΔPAO and ΔPTRACH (all r2 >0.93), with differing attenuation of the pressure wave. Delivered VT at the different settings tested varied between devices, with some unable to deliver VT >3 ml at 15 Hz, and others generating VT >20 ml at 5 Hz and a 1:1 inspiratory-to-expiratory time ratio.
Conclusions: Clinicians should be aware that modern high-frequency oscillators exhibit important differences in the delivered ΔP and VT.
|Item Type:||Refereed Article|
|Keywords:||high-frequency oscillatory ventilation, lung mechanics, mechanical ventilation, pressure amplitude|
|Research Division:||Biomedical and Clinical Sciences|
|Research Field:||Paediatrics not elsewhere classified|
|Objective Group:||Specific population health (excl. Indigenous health)|
|Objective Field:||Neonatal and child health|
|UTAS Author:||Dargaville, PA (Professor Peter Dargaville)|
|Web of Science® Times Cited:||16|
|Deposited By:||Menzies Institute for Medical Research|
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