Development and application of a double-piston configured, total-liquid ventilatory support device.
OBJECTIVE
Perfluorocarbon liquid ventilation has been shown to enhance pulmonary mechanics and gas exchange in the setting of respiratory failure. To optimize the total liquid ventilation process, we developed a volume-limited, time-cycled liquid ventilatory support, consisting of an electrically actuated, microprocessor-controlled, double-cylinder, piston pump with two separate limbs for active inspiration and expiration.


METHODS
Prospective, controlled, animal laboratory study, involving sequential application of conventional gas ventilation, partial ventilation (PLV), and total liquid ventilation (TLV).


METHODS
Research facility at a university medical center.


METHODS
A total of 12 normal adult New Zealand rabbits weighing 3.25+/-0.1 kg.


METHODS
Anesthestized rabbits were supported with gas ventilation for 30 mins (respiratory rate, 20 cycles/min; peak inspiratory pressure, 15 cm H2O; end-expiratory pressure, 5 cm H2O), then PLV was established with perflubron (12 mL/kg). After 15 mins, TLV was instituted (tidal volume, 18 mL/kg; respiratory rate, 7 cycles/min; inspiratory/expiratory ratio, 1:2 cycles/min). After 4 hrs of TLV, PLV was re-established.


RESULTS
Of 12 animals, nine survived the 4-hr TLV period. During TLV, mean values +/- SEM were as follows: PaO2, 363+/-30 torr; PaCO2, 39+/-1.5 torr; pH, 7.39+/-0.01; static peak inspiratory pressure, 13.2+/-0.2 cm H2O; static endexpiratory pressure, 5.5+/-0.1 cm H2O. No significant changes were observed. When compared with gas ventilation and PLV, significant increases occurred in mean arterial pressure (62.4+/-3.5 torr vs. 74.0+/-1.2 torr) and central venous pressure (5.6+/-0.7 cm H2O vs. 7.8+/-0.2 cm H2O) (p < .05).


CONCLUSIONS
Total liquid ventilation can be performed successfully utilizing piston pumps with active expiration. Considering the enhanced flow profiles, this device configuration provides advantages over others.
Meinhardt
J P
JP
Universitätsklinikum Mannheim, Fakultät für Klinische Medizin der Universität Heidelberg, Germany.
Quintel
M
M
Hirschl
R B
RB
D000818:Animals; D004867:Equipment Design; D005260:Female; D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; D008168:Lung / Q000503:physiopathology; D008176:Lung Volume Measurements; D008297:Male; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration / Q000295:instrumentation; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D011817:Rabbits; D013813:Therapy, Computer-Assisted / Q000295:instrumentation; D012122:Ventilators, Mechanical
D005466:Fluorocarbons; D006842:Hydrocarbons, Brominated; C003072:perflubron; D010100:Oxygen