Respiration rate control system

• US 3,889,669 A
• Filed: 12/11/1972
• Issued: 06/17/1975
• Est. Priority Date: 12/11/1972
• Status: Expired due to Term

• Current Assignee: James Weigl
• Original Assignee: James Weigl
• Inventors: Weigl, James
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Recla, Henry J.
• Application Number:
  US05/313,984
• Time in Patent Office: 918 Days
• Field of Search: 128/145.8,145.6,145.5,142.2,142,188 137/624.11,624.12,624.13,624.14,624.18
• US Class Current: 128/204.18
• 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: Y10T 137/86413 Self-cycling

Abstract

A system for timing the maximum lengths of inspiration and expiration phases of the respiration cycles of a positive pressure breathing apparatus, the rate control system including a timing cylinder with a movable piston therein forming two mutually adjustable timing chambers, two conduits receiving equal flows of gas through an adjustable needle valve and operable alternately to charge the respective chambers, and pressureresponsive actuators pressurized through the respective chambers and each operable upon attainment of a selected actuating pressure level in the associated chamber to produce a pressure signal for terminating one phase and initiating the next. The chambers are activated alternately by a controller which vents one chamber while sealing the other.

Claims

1. For use with a respiration apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, and comprising:

a hollow enclosure of regular cross-secTional shape having a movable wall dividing the interior of the enclosure into first and second timing chambers of mutually adjustable volumes;

means for variably positioning said wall within said enclosure to vary the ratio of the volumes of said chambers while maintaining a constant total volume;

means for supplying charging gas at the same preselected rate alternately to said chambers and raising the pressure therein from a preselected starting pressure level to a preselected actuating pressure level, whereby the time required to attain said actuating pressure level varies in accordance with the ratio of said volumes and the ratio of said volumes determines the ratio of inspiration time to expiration time;

means for selectively varying said preselected rate to adjust the cycle rate of said system independently of the ratio of inspiration time to expiration time; and

phase control means operable in response to attainment of said actuating pressure level in said first and second chambers to produce first and second signals, respectively, for terminating one phase of the respiration cycle and initiating the other phase thereof.

2. A rate control system as defined in claim 1 in which said enclosure is a cylinder and said wall is a piston slidably positioned therein.

3. A rate control system as defined in claim 2 in which said means for variably positioning said piston include a piston rod and a screw mechanism acting through said rod to slide said piston within said cylinder.

4. A rate control system as defined in claim 1 in which said means for supplying charging gas include a first conduit for receiving a supply flow of gas at regulated pressure, two charging conduits leading from said first conduit to said chambers, and means for dividing the supply flow into two equal charging flows.

5. A rate control system as defined in claim 4 in which said means for selectively varying said preselected rate comprises a calibrated needle valve controlling flow through said first conduit.

6. A rate control system as defined in claim 4 further including a controller for venting each of said chambers while sealing the other, thereby alternately activating said chambers, and means for actuating said controller in response to initiation of the respected phases of respiration.

7. A rate control system as defined in claim 1 in which said phase control means comprise pressure-responsive actuators receiving pressure from said chambers and operable upon attainment of said actuating pressure levels therein.

8. For use with a respiration apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, and comprising:

means defining first and second timing chambers of preselected volumes, said volumes having a preselected ratio;

means operable during each inspiration phase to charge said first chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

first phase-control means responsive to attainment of a preselected actuating pressure level in said first chamber to terminate the inspiration phase and initiate an expiration phase;

means operable during each expiration to change said second chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level; and

second phase-control means responsive to attainment of a selected actuating pressure level in said second chamber to terminate the expiration phase and initiate an inspiration phase, whereby said phases are timed in accordance with said charging rates and volumes to produce breathing cycles of selected length with each phase consituting a preselected portion of said length; and

in which said charging means for said chambers comprise a common source of gas undEr pressure producing a single regulated flow of gas, means dividing said regulated flow into two equal flows and directing such flows through first and second conduits to the respective chambers, and said first and second phase-control means include a controller operable during the inspiration phase to vent said second chamber while sealing said first chamber, and during said expiration phase to vent said first chamber while sealing said second chamber, said controller being actuated cyclically in response to the attainment of said preselected pressure levels in said chambers, and said controller including first and second vent orifices for venting said first and second conduits, respectively, a blocking member movable between two blocking positions over the respective orifices and operable in each blocking position to effect charging of the associated chamber through the associated conduit, and means operated by said first and second phase-control means to position said blocking member over one of said orifices to vent said second chamber during said inspiration phase and to vent said second chamber during said expiration phase.

9. A rate control system as defined in claim 8 in which said means for positioning said blocking member comprise a spring urging said blocking member toward one of said orifices, first and second inflatable actuators arranged on opposite sides of said member to urge the latter toward the first and second orifices respectively, when inflated, a source of fluid under pressure for each inflatable actuator, and means for applying the fluid under pressure to the respective inflatable actuators in response to attainment of preselected actuating pressure in the respective timing chambers.

10. For use with a respiration apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, and comprising:

means defining first and second timing chambers of preselected volumes, said volumes having a preselected ratio;

means operable during each inspiration phase to charge said first chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

first phase-control means responsive to attainment of a preselected actuating pressure level in said first chamber to terminate the inspiration phase and initiate an expiration phase;

means operable during each expiration to charge said second chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

second phase-control means responsive to attainment of a selected actuating pressure level in said second chamber to terminate the expiration phase and initiate an inspiration phase, whereby said phases are timed in accordance with said charging rates and volumes to produce breathing cycles of selected length with each phase constituting a preselected portion of said length;

means for selectively adjusting said rates, thereby to vary the charging times for said first and second timing chambers together and the total time of each breathing cycle; and

means for selectively adjusting the volume of each of said chambers, thereby to vary the charging times of said chambers with selected flow rates, and for maintaining the combined volumes of said chambers constant by increasing one volume in direct relation to any decrease in the other, thereby maintaining the total cycle time constant while varying the proportions thereof for the respective phases.

11. A rate control system as defined in claim 10 in which said flow-rate adjusting means comprises a needle valve through which fluid flows to both of said chambers.

12. A rate control system as defined in claim 10 in which each of said first and second phase-control means comprises a member movable between a timing positiOn and an actuating position, means normally holding said member in said timing position, and means responsive to the pressure level in the associated chamber and operable when such pressure level attains said actuating pressure level to move said member to said actuating position.

13. A rate control system as defined in claim 12 in which said pressure-responsive actuating means include inflatable members receiving fluid under pressure from the respective chambers and urging the levers toward the actuating positions to move them to such positions when the force moment of inflation exceeds the holding force moment.

14. A rate control system as defined in claim 13 in which each of said holding means include a magnet exerting a preselected holding force on said lever, and operable to release said lever with a snap action when the force moment of the associated inflatable member exceeds said holding force moment.

15. A rate control system as defined in claim 10 in which said charging means for said chambers comprise a common source of gas under pressure producing a single regulated flow of gas, means dividing said regulated flow into two equal flows and directing such flows through first and second conduits to the respective chambers, and said first and second phase-control means include a controller operable during the inspiration phase to vent said second chamber while sealing said first chamber, and during said expiration phase to vent said first chamber while sealing said second chamber, said controller being actuated cyclically in response to the attainment of said preselected pressure levels in said chambers.

16. For use with a respiration apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, and comprising:

means defining first and second timing chambers of preselected volumes, said volumes having a preselected ratio and said chambers having a common movable wall;

means operable during each inspiration phase to charge said first chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

first phase-control means responsive to attainment of a preselected actuating pressure level in said first chamber to terminate the inspiration phase and initiate an expiration phase;

means operable during each expiration to charge said second chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

second phase-control means responsive to attainment of a selected actuating pressure level in said second chamber to terminate the expiration phase and initiate an inspiration phase, whereby said phases are timed in accordance with said charging rates and volumes to produce breathing cycles of selected length with each phase constituting a preselected portion of said length; and

means connected with said movable wall to move the same back and forth within said chambers, for selectively adjusting the volume of each of said chambers, thereby to vary the charging times for said chambers with selected flow rates.

17. For use with a respiration apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, and comprising:

means defining first and second timing chambers or preselected volumes, said volumes having a preselected ratio;

means operable during each inspiration phase to charge said first chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level;

first phase-control means responsive to attainment of a preselected actuating pressure level in said first Chamber to terminate the inspiration phase and initiate an expiration phase;

means operable during each expiration to charge said second chamber with fluid at a preselected rate to raise the pressure level therein progressively from a selected starting pressure level; and

second phase-control means responsive to attainment of a selected actuating pressure level in said second chamber to terminate the expiration phase and initiate an inspiration phase, whereby said phases are timed in accordance with said charging rates and volumes to produce breathing cycles of selected length with each phase constituting a preselected portion of said length; and

in which each of said first and second phase-control means comprises a lever movable between a timing position and an actuating position, means normally holding said lever in said timing position, means responsive to the pressure level in the associated chamber and operable when said pressure level attains said actuating pressure level to move said lever to said actuating position, and a bleed orifice spaced from said lever in said timing position and blocked by said lever in said actuating position.

18. For use with a respirator apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, said system comprising:

timing chamber means of preselected volume for timing each breathing cycle;

means for charging said timing chamber means to a preselected pressure level with fluid entering at a preselected flow rate, thereby to time each breathing cycle;

a single rate control means for selectively adjusting the flow rate to vary the breathing cycle time independently of the ratio of inspiration time to expiration time;

pressure-actuated means coupled with said timing chamber means, for terminating the inspiration phase and initiating the expiration phase, and thereby dividing the breathing cycle time in a preselected ratio of inspiration time to expiration time; and

a single ratio control means for selectively varying the ratio of inspiration time to expiration time independently of the breathing cycle time.

19. For use with a respirator apparatus for delivering gas from a source of gas under pressure cyclically to a patient through delivery means, a rate control system for timing successive breathing cycles each having an inspiration phase followed by an expiration phase, said system comprising:

timing chamber means of preselected volume for timing each breathing cycle, said timing chamber means including first and second chambers;

means for charging to a preselected pressure level said first chamber during the inspiration phase, and said second chamber during the expiration phase, with fluid entering at a preselected flow rate, thereby to time each breathing cycle;

a single rate control means for selectively adjusting the flow rate to vary the breathing cycle time;

pressure-actuated means coupled with said timing chamber means, for terminating the inspiration phase and initiating the expiration phase, and thereby dividing the breathing cycle time in a preselected ratio of inspiration time to expiration time; and

a single ratio control means for selectively varying the ratio of inspiration time to expiration time independently of the breathing cycle time, said ratio control means including a movable piston separating said first and second chambers, whereby movement of said piston changes the ratio of inspiration time to expiration time independently of the breathing cycle time, by varying the ratio of the volumes of said first and second chambers independently of their total volume.