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Pressure and flow waveform characteristics of eight high-frequency oscillators


Harcourt, ER and John, J and Dargaville, PA and Zannin, E and Davis, PG and Tingay, DG, Pressure and flow waveform characteristics of eight high-frequency oscillators, Pediatric Critical Care Medicine, 15, (5) pp. e234-240. ISSN 1529-7535 (2014) [Refereed Article]

Copyright Statement

© 2014 The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

DOI: doi:10.1097/PCC.0000000000000111


OBJECTIVES: The differences in performance of early generation high-frequency oscillators have been attributed to their distinct pressure and flow waveforms. Recently, five new oscillators have been commercially released. The objective of this study was to characterize the pressure and flow waveforms of eight commercially available oscillators.

DESIGN: In vitro benchtop study.

SETTING: Tertiary pediatric teaching hospital.

INTERVENTIONS: Eight oscillators were evaluated using a test lung; mean airway pressure 10 and 20 cm H2O; frequencies 5, 10, and 15 Hz; pressure amplitude 30 cm H2O (or equivalent); compliance 1.0 mL/cm H2O; and endotracheal tube 3.5 mm. Ventilators tested were Sensormedics 3100A and B (Carefusion), SLE5000 (SLE), Fabian (Acutronic), Leonie+ (Heinen+Löwenstein), Sophie (Stephan), and VN500 and Babylog 8000 (Dräger).

MEASUREMENTS AND MAIN RESULTS: Pressure (airway opening, at oscillator and within the test lung) and airway opening flow waveforms were recorded. Airway opening waveforms were characterized by type (square or sine) and by determining power spectral density analysis. The Sensormedics A and B and the SLE5000 delivered square waves; all other oscillators generated sine waves. Sensormedics, the SLE5000, and the Sophie had a characteristic inspiratory slope (incisura). The pressure waveform within the test lung was a sine wave for all oscillators. Oscillators with square waves or an inspiratory incisura exhibited the highest number of nonfundamental frequency components on power spectral density analysis, suggesting more complex harmonic waveforms with potentially greater transmissive power to the lungs. At frequencies of 5 and 10 Hz, all ventilators, except Babylog 8000, generated airway pressure amplitudes greater than 28.6 cm H2O and tidal volumes greater than 6 mL at the airway opening.

CONCLUSIONS: Current high-frequency oscillators deliver different waveforms. As these may result in variable clinical performance, operators should be aware that these differences exist.

Item Details

Item Type:Refereed Article
Keywords:high-frequency oscillatory ventilation, infant, mechanical ventilation, power spectral density, respiratory monitoring
Research Division:Biomedical and Clinical Sciences
Research Group:Paediatrics
Research Field:Paediatrics not elsewhere classified
Objective Division:Health
Objective Group:Specific population health (excl. Indigenous health)
Objective Field:Neonatal and child health
UTAS Author:Dargaville, PA (Professor Peter Dargaville)
ID Code:118539
Year Published:2014
Web of Science® Times Cited:6
Deposited By:Menzies Institute for Medical Research
Deposited On:2017-07-13
Last Modified:2017-11-06

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