Werchowski J L, Sanders M H, Costantino J P, Sciurba F C, Rogers R M
Department of Medicine, University of Pittsburgh School of Medicine, Pennsylvania.
J Appl Physiol (1985). 1990 Apr;68(4):1732-8. doi: 10.1152/jappl.1990.68.4.1732.
The respiratory inductance plethysmograph (RIP) has recently gained popularity in both the research and clinical arenas for measuring tidal volume (VT) and changes in functional residual capacity (delta FRC). It is important however, to define the likelihood that individual RIP measurements of VT and delta FRC would be acceptably accurate (+/- 10%) for clinical and investigational purposes in spontaneously breathing individuals on continuous positive airway pressure (CPAP). Additionally, RIP accuracy has not been compared in these regards after calibration by two commonly employed techniques, the least squares (LSQ) and the quantitative diagnostic calibration (QDC) methods. We compared RIP with pneumotachographic (PTH) measurements of delta FRC and VT during spontaneous mouth breathing on 0-10 cmH2O CPAP. Comparisons were made after RIP calibration with both the LSQ (6 subjects) and QDC (7 subjects) methods. Measurements of delta FRC by RIPLSQ and RIPQDC were highly correlated with PTH measurements (r = 0.94 +/- 0.04 and r = 0.98 +/- 0.01 (SE), respectively). However, only an average of 30% of RIPQDC determinations per subject and 31.4% of RIPLSQ determinations per subject were accurate to +/- 10% of PTH values. An average of 55.2% (QDC) and 68.8% (LSQ) of VT determinations per subject were accurate to +/- 10% of PTH values. We conclude that in normal subjects, over a large number of determinations, RIP values for delta FRC and VT at elevated end-expiratory lung volume correlate well with PTH values. However, regardless of whether QDC or LSQ calibration is used, only about one-third of individual RIP determinations of delta FRC and one-half of two-thirds of VT measurements will be sufficiently accurate for clinical and investigational use.
呼吸感应体积描记器（RIP）最近在研究和临床领域都受到了欢迎，用于测量潮气量（VT）和功能残气量变化（δFRC）。然而，对于在持续气道正压通气（CPAP）下自主呼吸的个体，确定VT和δFRC的个体RIP测量值在临床和研究目的上达到可接受的准确性（±10%）的可能性很重要。此外，在通过两种常用技术（最小二乘法（LSQ）和定量诊断校准（QDC）方法）进行校准后，尚未在这些方面比较RIP的准确性。我们比较了在0-10 cmH2O CPAP下自主口呼吸时RIP与肺量计（PTH）对δFRC和VT的测量值。在使用LSQ（6名受试者）和QDC（7名受试者）方法对RIP进行校准后进行了比较。通过RIPLSQ和RIPQDC测量的δFRC与PTH测量值高度相关（分别为r = 0.94±0.04和r = 0.98±0.01（SE））。然而，每个受试者的RIPQDC测定平均只有30%，RIPLSQ测定平均只有31.4%准确到PTH值的±10%。每个受试者的VT测定平均有55.2%（QDC）和68.8%（LSQ）准确到PTH值的±10%。我们得出结论，在正常受试者中，经过大量测定，呼气末肺容积升高时δFRC和VT的RIP值与PTH值相关性良好。然而，无论使用QDC还是LSQ校准，δFRC的个体RIP测定中只有约三分之一以及VT测量值的三分之二中的一半对于临床和研究使用将足够准确。
