Beelen R M J, Smit H A, van Strien R T, Koopman L P, Brussee J E, Brunekreef B, Gerritsen J, Merkus P J F M
Department of Environmental and Occupational Health, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
Thorax. 2003 Sep;58(9):761-4. doi: 10.1136/thorax.58.9.761.
The short and long term variability of the interrupter technique was assessed to determine whether interrupter resistance is a stable individual characteristic over time. The effect of field and standardised measurement conditions on the within-subject variability of the interrupter technique was also examined.
The interrupter technique was studied under field and standardised conditions in children aged 3-6 years. Under field conditions, five investigators performed the measurements using two different measurement devices in random sequence. Both short term (20-30 minutes) and long term variability (median 38 days) were assessed in 32 children. Under standardised conditions, a single investigator conducted all measurements using a single device; the repeated measurements were conducted at the same time of day in a familiar quiet classroom. Long term variability (median 11 days) was estimated in 15 children. Within-subject standard deviations were estimated by analysis of variance with adjustment for the effects of different investigators and measurement devices on within-subject variability under field conditions.
Under field conditions within-subject standard deviations for short and long term variability were 0.10 kPa/l/s (adjusted 0.10 kPa/l/s) and 0.13 kPa/l/s (adjusted 0.14 kPa/l/s), respectively. Under standardised conditions the within-subject standard deviation for long term variability was 0.10 kPa/l/s.
Measurement of interrupter resistance under field conditions only slightly increased the within-subject variability compared with standardised conditions. The results indicate that interrupter resistance is a stable individual characteristic over a period of some weeks.
评估了阻断器技术的短期和长期变异性，以确定阻断器阻力是否随时间是一个稳定的个体特征。还研究了现场和标准化测量条件对阻断器技术受试者内变异性的影响。
在3至6岁儿童中，在现场和标准化条件下研究阻断器技术。在现场条件下，五名研究人员使用两种不同的测量设备随机顺序进行测量。在32名儿童中评估了短期（20 - 30分钟）和长期变异性（中位数38天）。在标准化条件下，一名研究人员使用单一设备进行所有测量；重复测量在一天中的同一时间在熟悉安静的教室中进行。在15名儿童中估计了长期变异性（中位数11天）。通过方差分析估计受试者内标准差，并针对现场条件下不同研究人员和测量设备对受试者内变异性的影响进行调整。
在现场条件下，短期和长期变异性的受试者内标准差分别为0.10 kPa/l/s（调整后0.10 kPa/l/s）和0.13 kPa/l/s（调整后0.14 kPa/l/s）。在标准化条件下，长期变异性的受试者内标准差为0.10 kPa/l/s。
与标准化条件相比，在现场条件下测量阻断器阻力仅略微增加了受试者内变异性。结果表明，阻断器阻力在数周时间内是一个稳定的个体特征。
