Snepvangers Yvonne, de Winter Peter, Burger Huibert, Brouwers Hens A, Bogaard Jan M, van der Ent Kors
Department of Pediatric Pulmonology, University Medical Center Utrecht, Utrecht, The Netherlands.
Pediatr Crit Care Med. 2003 Apr;4(2):227-32. doi: 10.1097/01.PCC.0000059334.04333.1B.
To assess the effects of different oxygen concentrations and flow rates on the measurement errors of neonatal pneumotachometers in heated and unheated situations and to develop correction factors to correct for these effects.
Prospective laboratory study.
Outpatient clinic with equipment in a standardized setting.
Neonatal pneumotachometers.
In standardized conditions, the tested pneumotachometer was calibrated at a flow rate of 3 L/min with 60% oxygen and was set in series with a closed spirometer system being used as a reference. Different air-flow levels (1-9 L/min) and oxygen concentrations (21-100%) were infused into the closed system with the pneumotachometer and spirometer.
The pneumotachometers were significantly affected by changing oxygen concentrations (p < .01) and increasing flow rates (p < .01), increasing the actually measured flow rate. Correction factors, developed by multiple regression analysis, significantly reduced the overall maximum errors of the pneumotachometers from -1.1 to 0.6 L/min to -0.5 to 0.4 L/min.
The effects of changes in oxygen concentrations and flow rates on neonatal pneumotachometers could be considerably decreased by the use of correction factors such as were calculated in this study. This will preclude frequent calibration procedures with actual flow and oxygen levels during changes in experimental settings.
评估不同氧浓度和流速对加热和未加热情况下新生儿呼吸流速计测量误差的影响，并制定校正因子以校正这些影响。
前瞻性实验室研究。
在标准化环境中的门诊诊所。
新生儿呼吸流速计。
在标准化条件下，将受试呼吸流速计在流速为3L/min、氧气浓度为60%的情况下进行校准，并与用作参考的封闭式肺量计系统串联设置。将不同的气流水平（1-9L/min）和氧气浓度（21%-100%）输入到装有呼吸流速计和肺量计的封闭系统中。
呼吸流速计受到氧浓度变化（p<.01）和流速增加（p<.01）的显著影响，实际测量流速增加。通过多元回归分析得出的校正因子显著降低了呼吸流速计的总体最大误差，从-1.1至0.6L/min降至-0.5至0.4L/min。
使用本研究中计算出的校正因子，可显著降低氧浓度和流速变化对新生儿呼吸流速计的影响。这将避免在实验设置变化期间频繁根据实际流速和氧水平进行校准程序。
