科研之友
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摘要
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 (Delta P), 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 (P-AW) 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 P-AW, frequency and ETT, the set Delta P was sequentially increased from 15 to 50 cm H2O, or from 20 to 100% maximum amplitude (10% increments) depending on the oscillator design. The Delta P at the ventilator (Delta P-VENT), airway opening (Delta P-AO) and within the test lung (Delta P-TRACH), and tidal volume (V-T) at the airway opening were determined at each set Delta P. Results: In two oscillators the relationships between set and delivered.P were non-linear, with a plateau in Delta P thresholds noted at all frequencies (Drager Babylog 8000) or >= 10 Hz (Drager VN500). In all other devices there was a linear relationship between Delta P-VENT, Delta P-AO and Delta P-TRACH (all r(2) > 0.93), with differing attenuation of the pressure wave. Delivered V-T at the different settings tested varied between devices, with some unable to deliver V-T > 3 ml at 15 Hz, and others generating V-T > 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 Delta P and V-T.
- 出版日期2015
