A Regulator for Pressure-Controlled Total-Liquid Ventilation

• Published in: IEEE transactions on biomedical engineering Vol. 57; no. 9; pp. 2267 - 2276
• Main Authors: Robert, Raymond, Micheau, Philippe, Avoine, Olivier, Beaudry, Benoit, Beaulieu, Alexandre, Walti, Hervé
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Biological and medical sciences; Computer Simulation; Emergency and intensive respiratory care; Equipment Design; Fluorocarbons - therapeutic use; In vitro; In vivo; Intensive care medicine; Liquid Ventilation - instrumentation; Liquid Ventilation - methods; liquid ventilator; Liquid-assisted ventilation; Lungs; Medical sciences; Models, Biological; newborn lambs; Numerical simulation; Pediatrics; perfluorochemical liquid; Pressure; Pressure control; Prototypes; Regulators; Robust control; Sheep - physiology; Tidal Volume - physiology; Ventilation; Ventilators; Human; Liquid-assisted ventilation; Ventilator; Assisted ventilation; Liquid ventilation; Perfluorocarbon; Pressure control; In vitro; Vertebrata; perfluorochemical liquid; Mammalia; Meat animals; liquid ventilator; Newborn animal; Sheep; Numerical simulation; Artiodactyla; newborn lambs; Mechanical ventilation; Ungulata; Biomedical engineering
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2009.2031096

Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acid-base equilibrium, and achieve greater minute ventilation, better oxygenation and CO 2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140 mL· min -1 ·kg -1 in order to ensure PaCO 2 below 55 mmHg. From a clinician's point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications.