1. Assessing the performance of the Whisperflow® continuous positive airway pressure generator: a bench study 
G.W. Glover, S.J. Fletcher 
British Journal of Anaesthesia 
Volume 102, Issue 6, Pages (June 2009)
DOI: /bja/aep077
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
Schematic diagram of spontaneously breathing model for dynamic tests.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
Pressure change across manikin airway/pneumotachograph complex as flow varies. Gradient of the line is resistance to flow. Normal value is ∼2 cm H2O litre−1 s.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

4. Fig 3
Typical recording of a dynamic test [set CPAP level 15 cm H2O (heavy dotted line) Fio2 0.3, Vt 600 ml, 40 bpm] with flow and pressure (p) recorded simultaneously. Demonstrates realistic flow/time waveform and cyclical variation in mask pressure around the 15 cm H2O set level and the exaggerated variability in the ‘trachea’.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

5. Fig 4
Peak inspiratory flow rate as a function of ventilatory frequency and tidal volume (300 ml light grey, 600 ml mid grey, and 900 ml dark grey bars) for the dynamic tests with the spontaneously breathing machine.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

6. Fig 5
Mean (95% CI) fresh gas flow rate of 11 Whisperflow devices under static conditions with varying CPAP load and Fio2.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

7. Fig 6
Mean (95% CI) circuit pressure maintained for five CPAP valves under static conditions as Whisperflow fresh gas flow rate varies.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions

8. Fig 7
Mean (Pmean) and minimum (Pmin) mask pressures during the dynamic protocol with 5 cm H2O (bottom group), 10 cm H2O (middle group), and 15 cm H2O (top group) valves and (a) Fio2 0.3, (b) Fio2 0.6, and (c) Fio2 0.9.
British Journal of Anaesthesia  , DOI: ( /bja/aep077)
Copyright © 2009 British Journal of Anaesthesia Terms and Conditions