RT Journal Article SR Electronic T1 In vitro assessment of equipment and software to assess tidal breathing parameters in infants JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 100 OP 107 DO 10.1183/09031936.01.17101000 VO 17 IS 1 A1 G. Schmalisch A1 B. Foitzik A1 R.R. Wauer A1 J. Stocks YR 2001 UL http://erj.ersjournals.com/content/17/1/100.abstract AB The aim of this in vitro study was to compare the measurement accuracy of two currently available devices for measuring tidal breathing in infants.A mechanical model pump was used to generate flow profiles which simulated those observed in infants. A range of flows was applied simultaneously to two different devices, namely the commercially available SensorMedics 2600 (SM 2600) and more recently developed, custom-made equipment based on the flow-through technique (FTT). Automatically derived values from both devices were compared with one another and with manual calculations of printouts of the same breaths.There were no differences in the raw flow signal obtained from the two devices, nor between values calculated automatically or manually from the FTT. Similarly, the deviations between the FTT and SM 2600 were <3% for tidal volume, respiratory frequency and minute ventilation. However, when comparing either with manually calculated values or those derived automatically from the FTT, there was a systematic and highly significant underestimation of shape-dependent parameters, such as the time to peak tidal expiratory flow as a proportion of tidal expiratory time (tPTEF/tE), derived by the SM 2600. The lower the applied flow, the higher the observed deviations, the underestimation being up to 60% when flows simulating those observed in preterm neonates were applied.These errors appear to result from differences in signal processing such as the algorithms used for breath detection and can only be detected if appropriate nonsinusoidal flow profiles representing those seen in infants are used to evaluate equipment.This work, was supported by the German Ministry for Research and Technology, project “Perinatal Lung” (grant 01 ZZ 9511) and Deutsche Forschungsgemeinschaft (Schm 1160/1-2).