Jensen Robert L, Teeter John G, England Richard D, Howell Heather M, White Heather J, Pickering Eve H, Crapo Robert O
Pulmonary Laboratory, LDS Hospital and University of Utah, Eighth Ave and C St, Salt Lake City, UT 84143, USA.
Chest. 2007 Aug;132(2):396-402. doi: 10.1378/chest.06-1999. Epub 2007 Mar 30.
The objective of the study was to characterize the biological and technical components of variability associated with longitudinal measurements of FEV(1) and carbon monoxide diffusing capacity (Dlco). Variability was apportioned to subject and instrument for five commercially available pulmonary function testing (PFT) systems: Collins CPL (Ferraris Respiratory; Louisville, CO); Morgan Transflow Test PFT System (Morgan Scientific; Haverhill, MA); SensorMedics Vmax 22D (VIASYS Healthcare; Yorba Linda, CA); Jaeger USA Masterscreen Diffusion TP (VIASYS Healthcare; Yorba Linda, CA); and Medical Graphics Profiler DX System (Medical Graphics Corporation; St. Paul, MN).
This was a randomized, replicated cross-over, single-center methodology study in 11 healthy subjects aged 20 to 65 years. Spirometry and Dlco measurements were performed at baseline, 3 months, and 6 months. Repetitive simulations of FEV(1) and Dlco were performed on the same instruments on four occasions over a 90-day period using a spirometry waveform generator and a Dlco simulator.
The coefficient of variation associated with repetitive measurements of FEV(1) or Dlco in subjects was consistently larger than that associated with repetitive simulated waveforms across the five instruments. Instrumentation accounted for 13 to 58% of the total FEV(1) and 36 to 70% of the total Dlco variability observed in subjects. Sample size estimates of hypothetical studies designed to detect treatment group differences of 0.050 L in FEV(1) and 0.5 mL/min/mm Hg in Dlco varied as much as four times depending on the instrument utilized.
These results provide a semiquantitative assessment of the biological and technical components of PFT variability in a highly standardized setting. They illustrate how instrument choice and test variability can impact sample size determinations in clinical studies that use FEV(1) and Dlco as end points.
本研究的目的是描述与第一秒用力呼气容积（FEV₁）和一氧化碳弥散量（Dlco）纵向测量相关的变异性的生物学和技术成分。对五种商用肺功能测试（PFT）系统的变异性按受试者和仪器进行了划分：柯林斯CPL（法拉利呼吸公司；科罗拉多州路易斯维尔）；摩根Transflow测试PFT系统（摩根科学公司；马萨诸塞州哈弗希尔）；森斯莫迪克斯Vmax 22D（VIASYS医疗保健公司；加利福尼亚州约巴林达）；耶格美国MasterScreen Diffusion TP（VIASYS医疗保健公司；加利福尼亚州约巴林达）；以及医学图形Profiler DX系统（医学图形公司；明尼苏达州圣保罗）。
这是一项针对11名年龄在20至65岁的健康受试者的随机、重复交叉、单中心方法学研究。在基线、3个月和6个月时进行肺活量测定和Dlco测量。在90天内，使用肺活量测定波形发生器和Dlco模拟器，在同一仪器上对FEV₁和Dlco进行了四次重复模拟。
在受试者中，与FEV₁或Dlco重复测量相关的变异系数始终大于在这五种仪器上与重复模拟波形相关的变异系数。仪器因素占受试者中观察到的总FEV₁变异性的13%至58%，占总Dlco变异性的36%至70%。旨在检测FEV₁中0.050 L和Dlco中0.5 mL/min/mm Hg治疗组差异的假设研究的样本量估计值，根据所使用的仪器不同，变化幅度高达四倍。
这些结果在高度标准化的环境中对PFT变异性的生物学和技术成分进行了半定量评估。它们说明了仪器选择和测试变异性如何影响以FEV₁和Dlco为终点的临床研究中的样本量确定。
