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110 CAN PIEZOELECTRIC TRANSDUCERS BE USED TO EVALUATE RESPIRATORY MECHANICS IN VENTILATED CHILDREN? ARCAS Group. V. Neve , R. Logier, Y. Riou, L. Storme, A. Martinot. F. Leclerc. University Hospital. 59037 Lille. France. Respiratory mechanics measurements are useful in mechanically ventilated children to optimize ventilator settings. Nevertheless, the transducers used to measure flow (F) and pressure (P) remain expensive. Objective. To evaluate the performances of piezoelectric P transducers (350 US Dollar) in measuring F and P. Methods. We used a previously described monitoring system measuring respiratory parameters [1]. In this study F was obtained by a differential piezoelectric P transducer (± 12.7 cmH 2O, Honeywell) whose sensitivity has been reduced to ± 2 cmH2O by an electronic amplification equipment and P by a piezoelectric P transducer (± 70.3 cmH2O, Honeywell) connected to a grid pneumotachymeter (PNT) (Fleisch 0 or 1). Volume (V) (5 to 400 ml) obtained by numeric integration of F (0.125 to 10 L/min ) and P (2 to 70 cmH2O) were respectively delivered through a calibrated seringe and an electronical manometer (Pic 400 Premier) and calculated by the computer. Bland and Altman analysis was used for assessment of results bias. Coefficient of repeatability (CR) was estimated by the standard deviation of repeated measurements of the parameters as calculated in a oneway analysis of variance. Results. Mean difference (Mdif) between injected V (5 to 50 ml) and measured V using PNT 0 was 0.15 ml, SD = 0.13 ml, Difference and mean V were not correlated. SD of repeated V measurements were not correlated to V. CR was 0.4 ml. Mdif between injected V (25 to 400 ml) and measured V using PNT 1 was 3 ml, SD = 6 ml. SD of repeated V measurements were not correlated to mean V. CR was 6 ml. Mdif between injected P and measured P was 0.3 cmH 2O, SD 0.4 cm H20. SD of repeated P measurements were not correlated to mean P. CR was 0.3 cmH20. Conclusion. Inexpensive piezoelectrical transducers can be used to measure F and P and evaluate respiratory mechanics in ventilated children. Reference. [1] Logier R et al. Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. 1993, Vol 15, 2, pp 1004-5. 112