Ventilator and method

• US 4,044,763 A
• Filed: 07/07/1975
• Issued: 08/30/1977
• Est. Priority Date: 07/07/1975
• Status: Expired due to Term

• Current Assignee: Forrest M. Bird
• Original Assignee: Forrest M. Bird
• Inventors: Bird, Forrest M.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Recla, Henry J.
• Application Number:
  US05/593,667
• Time in Patent Office: 785 Days
• Field of Search: 128/145.5, 128/145.6, 128/145.8, 128/142.3, 128/142.2, 128/142, 128/203
• US Class Current: 128/204.26
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/107 in the inspiratory path
• CPC Class Codes: Y10T 137/86413 Self-cycling

Abstract

Ventilator having an inhalation phase and an exhalation phase in its operative cycle for use with a source of gas under pressure. A master sequencing cartridge having an inlet adapted to be connected to a source of gas under pressure and an outlet is provided. The cartridge has a valve member movable between open and closed positions to control the flow of gas from the inlet to the outlet. The cartridge is provided with a diaphragm capable of operating under differentials in pressure for causing movement of said valve member. A breathing circuit outlet is provided and tubing is provided for coupling the breathing circuit outlet to the outlet of the master sequencing cartridge. A volume-rate control valve assembly is provided for controlling the movement of the valve member of the master sequencing cartridge between open and closed positions. The volume/rate control valve assembly has an inlet and an outlet with tubing coupling the inlet of the control valve assembly to the outlet of the master sequencing cartridge and tubing connecting the inlet to the diaphragm of the cartridge whereby the timing for moving the valve member between open and closed positions is determined by the rate of flow of gases through the volume/rate control valve assembly.

Claims

1. In a ventilator having an inhalation phase and an exhalation phase in its operative cycle for use with a source of gas under pressure, a master sequencing cartridge having an inlet adapted to be connected to the source of gas under pressure and an outlet, a valve member movable between open and closed positions for controlling the flow of gas from the inlet to the outlet, diaphragm means for moving said valve member from an open position to a closed position and forming first and second chambers in the cartridge on opposite sides of the diaphragm means, a breathing circuit outlet, breathing circuit means coupling the breathing circuit outlet to the outlet of the master sequencing cartridge, a single volume/rate control valve assembly having an inlet and an outlet with an orifice interconnecting the same and an adjustable needle valve disposed in the orifice, means coupling the inlet of the control valve assembly to the outlet of the master sequencing cartridge, means connecting the outlet of the control valve assembly to the first chamber on one side of the diaphragm means to bleed gas through the control valve assembly in one direction into said first chamber to move said valve member to terminate the inspiratory phase and initiate the expiratory phase and thereafter to bleed off gas from the first chamber through the control valve assembly in an opposite direction into the breathing circuit means whereby after sufficient bleed-off of gas from the first chamber the valve member moves to the open position to terminate the expiratory phase and initiate the inspiratory phase, and volume/rate control valve assembly including a single adjustable control means for the ventilator to control both the length of the inspiratory phase and the length of the expiratory phase such that an almost constant inspriatory expiratory time ratio from operative cyclic frequencies from over approximately 30 per minute down to approximately 5 per minute is maintained and a volume of gas to the patient which is substantially inverse to the rate is provided whereby, at high frequencies, there is a small tidal volume and at low frequencies there is a large tidal volume which meet the requirements for an infant and an adult, respectively.

2. A ventilator as in claim 1 together with a physiological triggering servo assembly, said servo assembly having an inlet coupled to the outlet of said volume/rate control valve assembly, an outlet open to ambient, a valve member movable between open and closed positions to control the flow of gas from the inlet to ambient, diaphragm means coupled to said valve member and means forming a chamber on one side of the diaphragm means and in communication with the breathing circuit outlet for sensing the pressure of gases in the breathing circuit outlet and means for adjusting the force which must be applied to the diaphragm to cause movement of said last named valve member to a closed position to terminate the flow of gas from the inlet to ambient.

3. A ventilator as in claim 1 wherein said means coupling the breathing circuit outlet to the outlet of the master sequencing cartridge includes an inspiratory flow/volume control valve assembly having an adjustable orifice therein.

4. A ventilator as in claim 1 wherein said master sequencing cartridge includes a sealing member for separating said valve member from said diaphragm, said sealing member being exposed to gas under pressure from the source of gas when the valve member has been moved to an open position so that the piston effect keeping the valve member in an open position is greater after the valve member has been opened than prior to the opening whereby there is a large differential between opening pressure of the valve member and the pressure required to close the valve member.

5. In a ventilator having an inhalation phase and an exhalation phase in its operative cycle for use with a source of gas under pressure, a master sequencing cartridge having an inlet adapted to be connected to the source of gas under pressure and an outlet, a valve member movable between open and closed positions for controlling the flow of gas from the inlet to the outlet, diaphragm means for moving said valve member from an open position to a closed position and forming first and second chambers in the cartridge on opposite sides of the diaphragm means, a breathing circuit outlet, breathing circuit means coupling the breathing circuit outlet to the outlet of the master sequencing cartridge, a volume/rate control valve assembly having an inlet and an outlet, means coupling the inlet of the control valve assembly to the outlet of the master sequencing cartridge, means connecting the outlet of the control valve assembly to the first chamber on one side of the diaphragm means to bleed gas through the control valve assembly in one direction into the first chamber to move said valve member to terminate the inspiratory phase and initiate the expiratory phase and thereafter to bleed off gas from the first chamber through the control valve assembly in an opposite direction into the breathing circuit outlet whereby after sufficient bleed-off of gas from the first chamber the valve member moves to the open position to terminate the expiratory phase and initiate the inspiratory phase, said volume/rate control valve assembly serving as a single control for the ventilator to control both the length of the inspiratory phase and the length of the expiratory phase and an additional flow path means coupled between said first chamber and said breathing circuit means for bleeding off gas from said first chamber to said breathing circuit outlet and including a one-way check valve for only permitting flow of gas from said first chamber and an adjustable control valve in series with said one-way check valve for controlling the rate of flow of gas from said first chamber to thereby make possible adjustment of the ratio of the length of the inspiratory phase to the length of the expiratory phase.

6. A ventilator as in claim 5 together with a balance reservoir connected between the outlet of the volume/rate control valve assembly and said first chamber and a balance orifice connected between said additional flow path means and the inlet of said control valve assembly.

7. In a method for controlling the inhalation phase and the exhalation phase in the operative cycle of a ventilator supplied with gas from a source of gas under pressure by the use of a single adjustable volume/rate control valve assembly in conjunction with a master sequencing cartridge having a diaphragm operated valve member for controlling the flow of gas to the patient with a normally open position and a chamber on one side of the diaphragm for receiving gas to move the diaphragm operated valve member to a closed position, initiating the flow of gas from the source of gas to the master sequencing cartridge bleeding gas from the source of gas at a controlled rate through the single volume/rate control valve assembly in one direction into the chamber to move the valve member to a closed position to terminate inspiratory flow, bleeding gas from the chamber at a controlled rate through the single volume/rate control valve assembly in an opposite direction to terminate the expiratory flow using the differential in opening and closing pressures for the diaphragm operated valve member to obtain a ratio between inspiratory and expiratory times and bleeding off additional gas from the chamber through a passage independent of the single volume/rate control valve assembly to adjust the ratio of the length of the inspiratory phase to the length of the expiratory phase.

8. A method as in claim 7 together with the step of applying additional pressure to the diaphragm operated valve means to keep it in an open position after it has been moved to an open position.