Correction factors for oxygen and flow-rate effects on neonatal Fleisch and Lilly pneumotachometers.

Objective: To assess the effects of different oxygen concentrations and flow rates on the measurement errors of neonatal pneumotachometers in heated and unheated situations and to develop correction factors to correct for these effects.

Design: Prospective laboratory study.

Setting: Outpatient clinic with equipment in a standardized setting.

Estimation of expiratory time constants via fuzzy clustering.

Objective: In mechanically ventilated patients the expiratory time constant provides information about respiratory mechanics. In the present study a new method, fuzzy clustering, is proposed to determine expiratory time constants. Fuzzy clustering differs from other methods since it neither interferes with expiration nor presumes any functional relationship between the variables analysed.