METHOD AND APPARATUS FOR INJECTING CONTRAST MEDIA INTO THE VASCULAR SYSTEM

• US 3,812,843 A
• Filed: 03/12/1973
• Issued: 05/28/1974
• Est. Priority Date: 03/12/1973
• Status: Expired due to Term

• Current Assignee: Lear Romec Corporation (Crane Company)
• Original Assignee: George S. Rives, John A. Wootten
• Inventors: Wootten, John A., Rives, George S.
• Primary Examiner(s): Medbery, Aldrich F.
• Application Number:
  US05/340,226
• Time in Patent Office: 442 Days
• Field of Search: 128/218A,2R,2A,DIG.1,215,236,2.5R 222/59,76,333
• US Class Current: 600/432
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/44 having means for cooling or heating the devices or media
• CPC Class Codes: Y10S 128/01 Motorized syringe

Abstract

A method and apparatus by which fluid is delivered either sequentially at two different rates or at one rate as desired. Suitable controls are provided for independently selecting such different flow rates and the duration of time of each flow rate, which may either be manually or automatically delivered. During the injection cycle, a slow prolonged infusion, typically 2 ml per second for 20 seconds is made into the femoral artery, immediately followed by a rapidly delivered bolus, typically 20 ml per second for 2 seconds. On completion of the injection, the low flow injection has reached the digital vessels and the high flow injection is localized in the distal aorta with all vessels between being opacified, whereby a single X-ray exposure may be taken from the aorta to the foot with the film positioned under the area of interest. The injection apparatus is relatively compact and permits both extension and retraction as well as rotation of the syringe assembly relative to the control cabinet. Suitable means are also provided for accommodating any misalignment between the syringe piston and ball screw shaft and also for absorbing the rotational forces acting on the ball screw shaft during axial movement thereof. A ground fault interrupter guards against current leakage to ground by removing the power from the motor and controls when the current leakage to ground exceeds a predetermined low level, for example, 0.5 milliamps.

Claims

1. Injection apparatus for injecting a fluid into the vascular system of a mammal comprising a syringe assembly including a syringe barrel containing a piston, means mounting said piston for axial movement within said syringe barrel for expelling said fluid therefrom, and control means for controlling the rate of speed of advance movement of said piston within said syringe barrel, said control means comprising means for independently preselecting more than one rate of speed of advance movement of said piston within said syringe barrel and the periods of times of duration of each advancement prior to such advancement, and means for sequentially advancing said piston at such preselected rates of speed for such preselected periods of time during such advancement of said piston.

2. The apparatus of claim 1 wherein said control means further comprises means for selectively stopping and restarting said piston at any time during such advancement.

3. The apparatus of claim 1 wherein said control means further comprises switch means including an automatic position which when depressed and released causes said piston to automatically sequentially advance at such preselected rates of speed for such preselected periods of time, and an off/manual position which when depressed and released stops such automatic advancement of said piston but continues such advancement as long as such off/manual position is depressed.

4. The apparatus of claim 1 wherein said control means further comprises means for preselecting a time delay for actuation of an X-ray machine upon completion of such sequential advancement of said piston.

5. The apparatus of claim 4 wherein said control means further comprises limit switch means for activating said time delay for such X-ray machine in the event that said piston reaches the end of its stroke before the preselected time.

6. The apparatus of claim 1 wherein said control means further comprises an electric motor for driving said piston, and means for varying the speed of said electric motor to vary the speed of advancement of said piston in accordance with the preselected settings of said control means.

7. The apparatus of claim 6 further comprising clutch means for transmitting power from said motor to said piston to protect against damage if said piston bottoms out and limit pressure developed.

8. The apparatus of claim 6 wherein said control means further comprises means for causing said motor to rotate in opposite directions to retract and extend said piston for respectively filling and emptying said syringe barrel.

9. The apparatus of claim 8 wherein said control means further comprises means for causing said motor to rotate at a slower speed during extension of said piston for emptying said syringe barrel than during retraction of said piston for filling said syringe barrel.

10. The apparatus of claim 8 further comprising limit switches for stopping said motor when said piston reaches either end of its stroke.

11. The apparatus of claim 6 further comprising a ground fault interrupter circuit associated with said control means for detecting current leaks to ground and removing the power from said control means.

12. The apparatus of claim 11 wherein said control means further comprises means for testing said ground fault interrupter circuit to check its operation.

13. The apparatus of claim 1 further comprising means for moving said piston at a faster rate for filling said syringe barrel than for emptying said syringe barrel.

14. The apparatus of claim 1 further comprising means for checking said syringe assembly for current leaks to ground prior to filling said syringe assembly with the desired quantity of fluid.

15. The apparatus of claim 1 further comprising a syringe cap and associated seal on the outer end of said syringe barrel.

16. Injection apparatus for injecting a fluid into the vascular system of a mammal comprising a syringe assembly including a syringe barrel containing a piston, means mounting said piston for axial movement within said syringe barrel for expelling said fluid therefrom, and control means for controlling the rate of speed of advance movement of said piston within said syringe barrel, said control means comprising means for independently preselecting more than one rate of speed of advance movement of said piston within said syringe barrel and volumes of each advancement prior to such advancement, and means for sequentially advancing said piston at such preselected rates of speed for such preselected volumes during such advancement of said piston.

17. Injection apparatus for injecting a fluid into the vascular system of a mammal comprising a syringe assembly including a syringe barrel containing a piston, and means mounting said piston for axial movement within said syringe barrel for expelling fluid therefrom, said last-mentioned means comprising a ball screw shaft connected to said piston, means mounting said ball screw shaft for axial movement but not rotational movement, a ball nut threadedly engaging said ball screw shaft, whereby rotation of said nut causes axial movement of said piston, and means for rotating said nut, said means mounting said ball screw shaft for axial movement but not rotational movement comprising a main support housing containing a longitudinally extending raceway for said ball screw shaft, said raceway being of generally channel shape, and a pair of ball bearing assemblies disposed on opposite sides of said ball screw shaft and connected thereto by a dowel pin extending through the center of said ball screw shaft and ball bearing assemblies, said ball bearing assemblies engaging said raceway to support said ball screw shaft for axial movement along said raceway and absorb any rotational forces acting on said ball screw shaft during such axial movement thereof.

18. The apparatus of claim 17 further comprising means providing a positive push-pull connection between said piston and ball screw shaft while accommodating any axial misalignment therebetween.

19. The apparatus of claim 18 wherein said last-mentioned means comprises a nut onto which said piston is threaded, said nut having a polygonal shaped recess therein, a push-pull screw attached to the outer end of said ball screw shaft, said screw having a head of a shape corresponding to the polygonal recess in said nut but slightly smaller than said recess for receipt therein with some radial clearance to accommodate any such misalignment between said piston and ball screw shaft while still permitting positive pushing and pulling of said piston during axial inward and outward movement of said ball screw shaft.

20. Injection apparatus for injecting a fluid into the vascular system of a mammal comprising a syringe assembly including a syringe barrel containing a piston, means mounting said piston for axial movement within said syringe barrel for expelling fluid therefrom, and a main support housing for said syringe assembly, said main support housing having an elongated tube projecting therefrom, and a control assembly for controlling the operation of said syringe assembly, said elongated tube extending into said control assembly, said control assembly including a support having an opening therethrough in which said tube is slidably received to permit both longitudinal and rotational movement of said syringe assembly relative to said control assembly, a pair of spaced apart stop rods mounted within said control assembly paralleling said tube adjacent opposite sides thereof, a stop screw on the distal end of said tube engageable with said stop rods to limit the rotation of said tube in opposite directions for all longitudinal adjusted positions of said syringe assembly relative to said control assembly, and means for clamping said syringe assembly in the desired longitudinal and rotational adjusted positions.

21. The apparatus of claim 20 wherein said means for clamping said syringe assembly in the desired longitudinal and rotational adjusted positions comprises a lock knob on said control assembly, a flexible collar surrounding said tube, and a rod extending from said lock knob and having threaded engagement with said collar for loosening and tightening said collar on said tube by rotation of said lock nut in opposite directions.

22. The apparatus of claim 20 further comprising a weight attached to said syringe assembly for locating the center of gravity of said syringe assembly closely adjacent the axis of rotation of said tube to facilitate rotation of the syringe assembly to any desired adjusted position.

23. The apparatus of claim 20 further comprising a support stand for said control assembly, and means mounting said control assembly on said support stand for vertical movement to provide for adjustment of the vertical height of the control assembly and syringe assembly connected thereto.

24. The apparatus of claim 20 wherein said means for moving said piston axially within said syringe barrel includes an electric motor for driving said piston, and clutch means for transmitting power from said motor to said piston to protect against damage if said piston bottoms out and limit pressure developed.

25. The apparatus of claim 24 further comprising a syringe housing surrounding said syringe barrel, means for releasably mounting said syringe barrel within said syringe housing, and means for electrically isolating said syringe barrel from said syringe housing.

26. The apparatus of claim 25 wherein said syringe housing includes a gear box containing drive mechanism for driving said piston by said motor, said syringe housing being attached to said main housing to provide a cover for said gear box.