Time of measurement influences the variability of tidal breathing parameters in healthy and sick infants

The aim of this study was to investigate the influence of the time, when me asuring tidal breathing parameters 1 min (epoch 1) and 5 min (epoch 2) afte r application of the facemask in healthy infants and infants with bronchopu lmonary dysplasia (BPD), using the dead space free flow-through technique. In both patient groups, there were no statistically significant differences between epoch 1 and 2, in most of the tidal breathing parameters, except a n increased VE and increased correlation dimension of the respiratory signa l in the BPD infants in epoch 1. However. in nearly all parameters the coef ficient of variation (CV) was significantly higher in epoch 1 compared with epoch 2. and in some infants. we found very high CVs ( > 50%) in epoch 1, which disappeared in epoch 2. The study shows that after having applied the Facemask, a sufficient amount of adaptation time is necessary in order to reduce the within-subject variability and improve the reproducibility and i nterpretation of tidal breathing measurements in infants. (C) 2001 Elsevier Science B.V. All rights reserved.