A supervisor for volume-controlled tidal liquid ventilator using independent piston pumps

Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions and lavage of inflammatory debris. This paper presents the control of a total liquid ventilator (TLV) dedicated to ventilate patients with completely filled lungs with a tidal volume of perfluorochemical liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy FRC modifications during ventilation. The prototype was tested on eight healthy term newborn lambs (<5 days old).