Design, development and experimental validation of a non-invasive device for recording respiratory events during bottle feeding

In newborns, a poor coordination between sucking, swallowing and breathing may undermine the effectiveness of oral feeding and signal immaturity of Central Nervous System. The aim of this work is to develop and validate a non-invasive device for recording respiratory events of newborns during bottle feeding. The proposed device working principle is based on the convective heat exchanged between two hot bodies and the infants' breathing. The sensing elements are inserted into a duct and the gas exchanged by infants is conveyed into this duct thanks to an ad hoc designed system to be mounted on a commercial feeding bottle. Two sets of experiments have been carried out in order to investigate the discrimination threshold of the device and characterize the sensor response at oscillating flows. The effect of distance and tilt between nostrils and device, and the breathing frequency, have been investigated simulating nostrils and neonatal respiratory pattern. The device has a discrimination threshold lower than 0.5 L/min at both 10° and 20° of tilt. Distance for these two settings does not affect the threshold in the investigated range (10-20 mm). Moreover, the device is able to detect breathing events, and to discriminate the onset of expiratory phase, during a neonatal respiratory task delivered by a lung simulator. The results foster the successful application of this device to the assessment of the temporal breathing pattern of newborns during bottle feeding with a non-invasive approach.