Experimental analysis of the airway circuit effects on breathing pattern generated by neonatal pulmonary ventilators

The effect of airway-to-patient circuit on the breathing pattern actually delivered to the patient by a neonatal pulmonary ventilator is in vitro experimentally examined. To this aim, an automatic measuring system capable to record: (a) the ventilation parameter analog output signals provided by the ventilator and (b) the pressure value directly measured at patient delivery site was implemented. The experimental analysis is conducted by examining various circuit configurations (tubes that differ in dimensions and rigidity, with and without humidifier, etc.) and pressure waveform changes are reported and compared. Noticeable differences between the respiratory pattern set by physicians and that actually delivered at the patient site are observed and the measured data provide indication for correct air circuit design. Finally, the hereby presented results contributed to increase the attention of the medical therapist, who is the only one able to estimate the actual patient ventilatory needs and their ranges of variation, to a more accurate ventilator setting in order to assure the correct breathing pattern for neonate health.