RT Journal Article
SR Electronic
T1 Validating Reference Equations for Impulse Oscillometry in Healthy Mexican Children
JF Respiratory Care
FD American Association for Respiratory Care
SP 1156
OP 1165
DO 10.4187/respcare.05247
VO 62
IS 9
A1 Laura Gochicoa-Rangel
A1 Rodrigo del Río-Hidalgo
A1 Juana Hernández-Ruiz
A1 Luis Rodríguez-Moreno
A1 David Martínez-Briseño
A1 Uri Mora-Romero
A1 Silvia Cid-Juárez
A1 Cecilia García-Sancho
A1 Luis Torre-Bouscoulet
YR 2017
UL http://rc.rcjournal.com/content/62/9/1156.abstract
AB BACKGROUND: The impulse oscillometry system (IOS) measures the impedance (Z) of the respiratory system, but proper interpretation of its results requires adequate reference values. The objectives of this work were: (1) to validate the reference equations for the IOS published previously by our group and (2) to compare the adjustment of new available reference equations for the IOS from different countries in a sample of healthy children.METHODS: Subjects were healthy 4–15-y-old children from the metropolitan area of Mexico City, who performed an IOS test. The functional IOS parameters obtained were compared with the predicted values from 12 reference equations determined in studies of different ethnic groups. The validation methods applied were: analysis of the differences between measured and predicted values for each reference equation; correlation and concordance coefficients; adjustment by Z-score values; percentage of predicted value; and the percentage of patients below the lower limit of normality or above the upper limit of normality.RESULTS: Of the 224 participants, 117 (52.3%) were girls, and the mean age was 8.6 ± 2.3 y. The equations that showed the best adjustment for the different parameters were those from the studies by Nowowiejska et al (2008) and Gochicoa et al (2015). The equations proposed by Frei et al (2005), Hellinckx et al (1998), Kalhoff et al (2011), Klug and Bisgaard (1998), de Assumpção et al (2016), and Dencker et al (2006) overestimated the airway resistance of the children in our sample, whereas the equation of Amra et al (2008) underestimated it. In the analysis of the lower and upper limits of normality, Gochicoa et al equation was the closest, since 5% of subjects were below or above percentiles 5 and 95, respectively. The study found that, in general, all of the equations showed greater error at the extremes of the age distribution.CONCLUSIONS: Because of the robust adjustment of the present study reference equations for the IOS, it can be recommended for both clinical and research purposes in our population. The differential adjustment of other equations underlines the need to obtain local reference values.