A Prototype of Volume-Controlled Tidal Liquid Ventilator Using Independent Piston Pumps

Robert, Raymond*; Micheau, Philippe*; Cyr, Stéphane*; Lesur, Olivier†; Praud, Jean-Paul‡; Walti, Hervé‡

doi: 10.1097/01.mat.0000249016.31910.11
Respiratory Support

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. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC 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 Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume.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 functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink–type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range.

From the *Department of Mechanical Engineering, †Department of Medicine, and ‡Department of Pediatrics, University of Sherbrooke, Sherbrooke, Quebec, Canada.

Submitted for consideration April 2006; accepted for publication in revised form July 2006.

Reprint Requests: Dr. Raymond Robert, Department of Mechanical Engineering, University of Sherbrooke, 2500 University Boulevard, Sherbrooke, Quebec, Canada, J1K 2R1.

Presented in part at The Fifth European Symposium on Perfluorocarbon (PFC) Application, Milano, Italy, March 17 to 18, 2006.

Copyright © 2006 by the American Society for Artificial Internal Organs