Enhanced chest compressor

• US 20080287863A1
• Filed: 05/18/2007
• Published: 11/20/2008
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Sunlife Science Inc.
• Original Assignee: Weil Institute Of Critical Care Medicine
• Inventors: Tang, Wanchun, Bisera, Joe, Weil, Max Harry, Castillo, Carlos
• Granted Patent: US 8,790,285 B2
• Time in Patent Office: Days
• US Class Current: 604/44
• CPC Class Codes: A61H 2201/018 By limiting the applied torque or force
• CPC Class Codes: A61H 2201/1238 with hydraulic or pneumatic drive
• CPC Class Codes: A61H 2201/1246 by piston-cylinder systems
• CPC Class Codes: A61H 31/00 Artificial respiration or heart stimulation, e.g. heart massage artificial respiration by treatment with gas or air, e.g. mouth-to-mouth respiration A61M16/00; applying electric currents by contact electrodes for stimulation, e.g. heart pace-makers A61N1/36 ; teaching or training models, demonstration models for medical purposes G09B23/288
• CPC Class Codes: A61H 31/006 Power driven

Abstract

A chest compressor includes a piston (14) that moves in downward and upward strokes, with the piston undergoing a smooth reversal at the bottom of the downward stroke. A compression spring such as a wave spring (60), is positioned to engage the piston only near the end of its downward stroke, to smoothly reverse the piston motion, limit downward force on the patient at the end of the stroke, and avoid a downward pulse due to the momentum of the downwardly-moving piston. A stop (90, 92) is latchable in an inward position to allow reduction in the piston stroke by engaging an outward flange (56) on the piston before the piston has moved fully downward.

Claims

1. Apparatus for applying compressions to the chest of a patient which includes an actuator comprising a cylinder and a piston that is actuatable to move in the cylinder in a downstroke toward the patient and in an upstroke away from the patient, wherein:

said actuator includes spring means that engages said piston to slow its downward movement and reduce its downward force only when the piston is closer to the end of a downstroke than when the piston is at the beginning of a downstroke.

2. The apparatus described in claim 1 wherein:

said piston has a part with an outward flange and said actuator has an inward flange lying below said piston outward flange, and said spring means is a wave spring that lies between said flanges to start to be compressed near the end of the piston downstroke.

3. The apparatus described in claim 1 wherein:

said spring means is a compression spring that is positioned to first be compressed by the downwardly moving piston only when the piston has completed at least two-thirds of its downstroke.

4. The apparatus described in claim 1 wherein:

said piston includes a piston part that is guided in sliding movement by said cylinder along a path of a first length that extends along a downstroke and including;

a stop that is moveable from a nonlimiting location to a limiting location that lies in the path of said piston part, with the stop being latchable in said limiting location to reduce the length of downstroke movement of the piston part along each downstroke.

5. Apparatus for applying chest compressions to a patient, which includes an actuator comprising a cylinder and a piston with a piston part that is actuatable to move in a downstroke towards the patient and an upstroke away from the patient, including:

a stop that is moveable between a first location, to a limiting location that lies in the path of the piston part to reduce the length of the piston downstroke, said stop being latchable in said limiting location.

6. The apparatus described in claim 5 wherein:

said piston part has an axis and has an outwardly-extending flange that moves up and down, and said stop comprises a pin that is moveable radially inward to said limiting location wherein said pin lies in the path of said flange, said pin being moveable outward to said first location.

7. The apparatus described in claim 6 wherein:

said stop includes a double click mechanism that latches said pin in said limiting location, and that latches said pin in said first location when the pin pressed radially inward from said first location to said limiting location.

8. The apparatus described in claim 5 including:

a compression spring that lies in the path of said piston and that is positioned to engage said piston only after said piston has moved more than half a distance of a downward stroke of said piston during its downward stroke.

9. Apparatus for applying chest compressions to a patient, comprising:

a cylinder and a piston that is moveable up and down by a first distance relative to the reclined patient, while guided by said cylinder;

a spring positioned to engage said piston and reduce the downward force it can apply, only when the piston has moved along at least half of said first distance.

10. The apparatus described in claim 9 wherein:

said cylinder has an axis, said piston has an outside flange that moves up and down, and said spring is a compression spring that lies in the path of said flange as said flange moves down.

11. The apparatus described in claim 10 wherein:

said compression spring is a wave spring.

12. The apparatus described in claim 9 wherein:

said piston includes outer and inner piston part that telescope in one another with said outer piston part slideably engaged with and guided by said cylinder and said inner piston part lying in and slidably engaged with and guided by said first piston part;

said spring is a compression spring that is supported by said outer piston part and that lies in the path of movement of said second piston part.

13. The apparatus described in claim 9 wherein:

said piston has an external piston flange; and

including

at least one stop that has a pin that is moveable to and latchable at first and second positions lying respectively in the path of and out of the path of said piston flange.