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Table 4 Respiratory System Reference Equations Obtained by the Impulse Oscillometry System for Boys and Girls

From: Reference values of impulse oscillometry (IOS) for healthy Chinese children aged 4–17 years

IOS parameters Equations R R2 SE of the estimate
Boy     
 R5, kPa/L/s 1.894 – 0.007 × H-0.028 × A + 0.002 × W 0.620 0.385 0.264
 R20, kPa/L/s 1.087 – 0.004 × H-0.010 × A + 0.001 × W 0.608 0.370 0.136
 X5, kPa/L/s − 0.554 + 0.002 × H + 0.007 × A 0.566 0.321 0.091
 Z5, kPa/L/s 1.934 – 0.008 × H-0.017 × A + 0.002 × W 0.716 0.513 0.189
 Fres, Hz 31.885 – 0.094 × H − 0.257 × A + 0.035 × W 0.532 0.283 3.615
 R5–R20, kPa/L/s 0.703–0.003 × H − 0.013 × A + 0.001 × W 0.536 0.287 0.133
Girl     
 R5, kPa/L/s 1.834–0.008 × H-0.0190 × A + 0.003 × W 0.677 0.458 0.176
 R20, kPa/L/s 0.964 – 0.003 × H-0.009 × A 0.562 0.316 0.123
 X5, kPa/L/s − 0.563 + 0.002 × H + 0.006 × A 0.542 0.294 0.089
 Z5, kPa/L/s 1.970–0.009 × H-0.020 × A + 0.003 × W 0.696 0.484 0.180
 Fres, Hz 33.941 – 0.104 × H-0.303 × A + 0.040 × W 0.494 0.244 4.027
 R5–R20, kPa/L/s 0.787 – 0.004 × H − 0.012 × A + 0.002 × W 0.533 0.284 0.130
  1. R5 = resistance at 5 Hz, R20 = resistance at 20 Hz, X5 = reactance at 5 Hz, Fres = resonant frequency, Z5 = impedance at 5 Hz, R5–R20 = fall in resistance between R5 and R20