Leipälä J A, Iwasaki S, Milner A, Greenough A
Children Nationwide Neonatal Intensive Care Unit, King's College Hospital, London, UK.
Arch Dis Child Fetal Neonatal Ed. 2004 Mar;89(2):F174-6. doi: 10.1136/adc.2002.023937.
To determine the effect of frequency on the accuracy of volume and pressure displays of high frequency oscillators.
The effect of frequency on the displayed volume of the Stephanie, Dräger Babylog 8000 Plus, and SLE 5000 oscillators was assessed. A sine wave pump delivered a constant tidal volume at frequencies of 5-15 Hz to the patient manifold of the oscillators. The displayed volumes at each frequency were compared with the delivered volume. The effect of frequency on displayed pressure was assessed by connecting the oscillator's patient manifold to a lung model; three types of oscillator were studied (SensorMedics 3100A, SLE 5000, and Stephanie). Airway pressure was measured from the manifold using a pressure transducer and non-compliant tubing; the pressure measuring system had a flat frequency response to 30 Hz.
The SLE 5000 volume display overread the delivered volume (by about 5%), but was not affected by frequency. At 5 Hz, the Dräger Babylog 8000 Plus and the Stephanie underread the delivered volume (by about 20%). Increasing frequency resulted in a greater discrepancy between the delivered and displayed volume with the Stephanie, but a smaller discrepancy with the Dräger Babylog 8000 Plus. Altering frequency had a small effect (maximum difference 6%) on the relation between the displayed and delivered pressure for all three oscillators.
Frequency affects the accuracy of displayed volumes and, to a lesser extent, displayed pressures of high frequency oscillators. The results emphasise that data displayed by new devices should not be uncritically accepted.
确定频率对高频振荡器容积和压力显示准确性的影响。
评估频率对斯蒂芬妮（Stephanie）、德尔格婴儿呼吸机8000 Plus（Dräger Babylog 8000 Plus）和SLE 5000振荡器显示容积的影响。一个正弦波泵以5 - 15赫兹的频率向振荡器的患者集管输送恒定潮气量。将每个频率下显示的容积与输送的容积进行比较。通过将振荡器的患者集管连接到肺模型来评估频率对显示压力的影响；研究了三种类型的振荡器（SensorMedics 3100A、SLE 5000和斯蒂芬妮）。使用压力传感器和无顺应性管路从集管测量气道压力；压力测量系统在30赫兹以下具有平坦的频率响应。
SLE 5000的容积显示高于输送的容积（约5%），但不受频率影响。在5赫兹时，德尔格婴儿呼吸机8000 Plus和斯蒂芬妮的显示容积低于输送的容积（约20%）。频率增加导致斯蒂芬妮显示的容积与输送的容积之间的差异更大，但德尔格婴儿呼吸机8000 Plus的差异较小。改变频率对所有三种振荡器显示压力与输送压力之间的关系影响较小（最大差异6%）。
频率会影响高频振荡器显示容积的准确性，并在较小程度上影响显示压力的准确性。结果强调，新设备显示的数据不应被不加批判地接受。
