A pure fluid cycling breathing valve has been discussed. The unit has no moving parts, valving being accomplished by interplay of laminar and turbulent gas flows through specially shaped passages. As an IPPB unit, the device affords minute volumes of 6 to 12 liters at inspiratory pressures of 10 to 20 cm H2O, and at ventilation rates adequate for all subjects. The inhalation-exhalation time ratio is about 1 to 2, and the valve will cycle automatically in a minimum-leak system. The unit will operate from a standard medical gas flowmeter or pressure regulator. There is a provision for aerosol nebulization.
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References
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AngristStanley W.: Fluid Control Devices, Sci. Amer., 211:80, 1964.
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CoandaHenri: Device for Deflecting a Stream of Elastic Fluid Projected into an Elastic Fluid, U.S. Patent No. 2,052,869, September, 1936.
3.
CournandA., et al.: Physiological Studies of the Effects of Intermittent Positive Pressure Breathing on Cardiac Output in Man, Amer. J. Physiol.152:162, 1948.
