The reproducibility and acceptability of airways resistance measurements us
ing the interrupter technique (MicroRint) obtained using a mouthpiece were
compared with those using a face mask.
Fifty children aged 4-7 yrs performed four sets of six Rint measurements; t
no using a mouthpiece and two using a face mask with integral mouthpiece.
Complete data were obtained from 45 (90%) children using the mouthpiece and
43 (86%) children using the mask. The tno methods were equally repeatable
with comparable intraclass correlation coefficients (ICC) and coefficients
of variation. Mean Rint values obtained using the mouthpiece were significa
ntly lo,rer than those using the face mask ((mean +/- SD) mouthpiece = 0.81
+/-0.18 kPa.L-1.s, mask = 0.88 +/-0.24 kPa.L-1.s p = 0.0002), Although the
mean paired differences between the tno methods were small (0.07 kPa.L-1.s
), the ICC and limits of agreement confirmed that the two methods could not
be used interchangeably. Sixty-seven per cent of children preferred the fa
ce mask but this was more time-consuming (p = 0.03), Children did not produ
ce more repeatable results using their preferred method, nor did they impro
ve with practice.
Repeatable airway resistance measurements using the interrupter technique r
an be obtained from young children using either a mouthpiece or a face mask
, but there are significant clinical and statistical differences between th
e results obtained.