Therapeutic Fluid Flow Control Apparatus

Abstract

A device which automatically both agitates an anticoagulant medium with inflowing blood during a blood collection process and terminates the process after a predetermined quantity of blood has been collected. The device includes a weight longitudinally slidable on a lever type scale arm to permit accurate selection of the blood quantity collected.

Description

This invention relates generally to a therapeutic fluid flow control apparatus and, more specifically relates to an apparatus for the collection of blood.

There exist various therapeutic applications wherein a precise control of fluid flow is required. Generally the applications entail the transfer of predetermined specific quantities of fluid from one location to another. Typical examples include the transfer of blood from a blood donor to a suitable collection vessel and the transfer of blood, blood preparations, and other therapeutic fluids from suitable containers to a patient. Since the permissible fluid flow rates are low, a relatively lengthy period generally is required for transfer of a desired fluid quantity. Thus, a system which accurately and automatically controls the amount of fluid transferred is extremely useful both for reasons of exactness and for eliminating the requirement for continuous monitoring of the transfer process by highly trained personnel.

U.S. Pat. No. 2,784,932 describes such a system including a stationary member which pivotally supports a two-arm scale lever having one arm adapted to support the blood collection vessel and an opposite arm supporting a weight selected to counterbalance the combined weight of the collection vessel and desired quantity of blood. After transfer of the predetermined weight of blood into the collection vessel, the position of the lever automatically shifts to pinch closed the flexible tubing joining the collection vessel and blood donor thereby terminating the collection process.

Although the device described in the above noted patent substantially simplified blood collection techniques, a need exists for improved equipment of this type, particularly for a unit offering greater and simpler selectivity of the fluid quantities controlled. However, fluid quantity adjustments should not be easily susceptible to modification by unauthorized personnel. Also, although automatically stopping the collection process after accumulation of a desired quantity of blood, the described device does not completely eliminate the requirement for supervision in that trained personnel must periodically agitate the collection vessel to insure thorough mixing of the previously introduced anticoagulant medium and the inflowing blood.

The object of this invention, therefore, is to provide a therapeutic fluid flow control device which automatically stops fluid flow after transfer of a given predetermined fluid quantity and which exhibits a simpler and more selective adjustment mechanism for determining the quantity of fluid controlled.

Another object of this invention is to provide a therapeutic fluid flow control device of the above featured type wherein the adjustment mechanism is relatively tamper-proof from unauthorized personnel.

Another object of this invention is to provide a blood collection control device which both terminates a blood collection process after transfer of a desired quantity of blood and agitates the blood container during the transfer process to insure thorough mixing of a previously introduced anticoagulant medium with the incoming blood.

One feature of this invention is a provision of a therapeutic fluid flow control unit of the type described in the above noted patent and including a slidable selector weight adapted for selective engagement with a plurality of graduated stops on the unit's counterbalance lever arm. The selector weight permits simple and accurate selection of the precise quantity of transferred fluid which will actuate the lever arm and terminate the transfer process.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type including a releasable biasing mechanism which inhibits relative movement between the selector weight and counterbalance lever arm. The biasing mechanism improves the stability of the device and prevents unintentional altering of a preselected fluid quantity setting by inadvertent movement of the selector weight.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type wherein the releasable biasing mechanism is substantially enclosed by the selector weight so as to be substantially hidden from view. This feature renders the device relatively tamper-proof from unauthorized personnel unfamiliar with the device's operation.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type wherein the release for the releasable biasing mechanism is disposed in the bottom surface of the selector weight so as to be somewhat concealed from the view of unauthorized personnel.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type particularly suited for blood collection and including a movable support for the blood collecting vessel. An electrically energizable drive means is coupled to the vessel support and is adapted upon energization to produce movement thereof. Automatically induced movement of the blood collection vessel insures continuous agitation of the incoming blood with the previously introduced anticoagulant medium thereby eliminating the requirement that this necessary action be performed manually.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type wherein the movable blood collection vessel support includes a cradle attached to a lever arm of the device by a yoke member, and the drive means comprises an electric motor and drive shaft operatively coupled between the cradle and yoke member and adapted upon energization to produce a rocking movement of the cradle. This arrangement provides in a relatively simple and efficient structure the desired continuous mixing of blood and anticoagulant medium.

Another feature of this invention is the provision of a therapeutic fluid flow control device of the above featured type wherein the electrical leads connected to the electric motor include intermediate portions attached to the stationary part of the device. By fixing the electrical leads to the unit's stationary portion, the possibility of having undesired forces exerted by the electrical cord on the balanced lever arm is eliminated.

These and other objects and features of the present invention will become more apparent upon a perusal of the following specification taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a front view of a preferred embodiment of the invention;

FIG. 2 is a top view of the embodiment shown in FIG. 1;

FIG. 3 is an end view of the embodiment shown in FIGS. 1 and 2;

FIG. 4 is a cross-sectional view taken along the lines 4-4 of FIG. 1;

FIG. 5 is a front view of the biasing pin 63 shown in FIG. 4; and

FIG. 6 is a partial view showing the embodiment of FIG. 1 in an actuated position.

Referring now to FIGS. 1--3, there is shown the stand 11 supporting the collapsible, sealed plastic blood pack 12. The blood pack 12 may be, for example, of the type shown and described in U.S. Reissue Pat. No. 25,129. Attached to the blood pack 12 and communicating with the interior thereof is the flexible tubing 13. The opposite end of the flexible tubing 13 terminates with the hypodermic needle 14 suitable for insertion into the vein of a blood donor (not shown) so as to permit filling of the blood pack 12 in the conventional manner.

Included in the stand 11 is the cylindrical rod 15 which extends through an aperture 16 in the stationary support block 17 and is fixed thereon by the thumbscrew 18. The stationary block 17 includes the rear block portion 19 and the overhanging front block portion 21 possessing the lateral slot 22.

Extending below the front block portion 21 ahead of the lateral slot 22 is the projection 23 having the laterally disposed groove 24 which accommodates the flexible tubing 13. The position of the flexible tubing 13 is established also by the bracket 25 mounted on the stationary front block portion 21. The lower end of the cylindrical rod 15 is supported within the base member 26.

The two-arm lever member 28 is pivotally supported within the slot 22 by the pivot pin 27 which extends between the rear block portion and the projection 23. Forming the lever member 28 are the integrally joined upwardly inclined arm 29 and the horizontal arm 31. The triangularly shaped nip 32 is formed on the horizontal arm 31 directly adjacent the projection 23. In the inactivated position shown in FIG. 1, the upper apex of the nip 32 is aligned with the lower edge of the groove 24.

Suspended from the end of the inclined arm 29 is the blood pack support assembly 35 including the cradle pan 36 and attached yoke member 37. The knob 38 on the inclined lever arm 29 accommodates an aperture in the flattened end portion 39 of the yoke member 37 which is retained in position by the clip 41. The bottom of the yoke member 37 is formed by the horizontal portions 42 joined by the arched portion 43. Attaching the cradle pan 36 and yoke member 37 are the rings 44 which permit rotational movement of the horizontal yoke portions 42.

Fixed to the bottom surface of the cradle pan 36 is the electric motor 45 having the eccentric drive shaft 46. The shaft 46 is received by aligned apertures in the U-shaped disc 47 mounted on the arched yoke portion 43. In response to forces applied by the shaft 46, the disc 47 moves both rotationally and longitudinally with respect to the arched portion 43. The electrical motor leads 48 extend through the hollow interior of the yoke member 37 and are supported by the clip 49 on the rear surface of the inclined lever arm 29 and by the terminal box 51 mounted on the rear block portion 19. The leads 48 terminate with the plug 52 adapted for insertion into a conventional electrical wall socket (not shown).

Secured to the end of the horizontal lever arm 31 by the recessed screw 55 is the counterbalance weight 56. Also mounted on the horizontal arm 31 for longitudinal sliding movement thereon is the selector weight 57. As shown in FIG. 4, the selector weight possesses an internal slot 58 which accommodates the horizontal lever arm 31 and an adjoining frontal opening 59 which exposes graduations printed on the front face thereof. The selector weight 57 also possesses a vertically disposed cylindrical bore 61 having an opening in the selector weight's bottom surface 62. Retained within the cylindrical bore 61 is a releasable biasing mechanism including the cylindrical pin 63 and the compression spring member 64. The cylindrical pin 63 possesses a groove 65 of slightly greater width than the horizontal lever arm 31 which it accommodates. Formed in the upper edge of the groove 65 are the plurality of uniformly spaced teeth 66, shown in FIG. 5, adapted for simultaneous engagement with selected sets of the notches 67 cut in the upper edge of the horizontal lever arm 31. The uniformly spaced notches 67 are aligned with the graduations printed on the front surface of the horizontal lever arm 31.

To operate the control device 11, the support block 17 is located at a desirable height on the support rod 15 and secured by tightening of the thumbscrew 18. The selector weight 57 is adjusted longitudinally on the horizontal lever arm 31 until the indicator 69 points to a graduation indicating the weight at which actuation of the scale lever 28 is desired. Then the motor 45 is energized by inserting the plug 52 into an electrical outlet (not shown) and the needle 14 is injected into a vein of a blood donor (not shown) to initiate the blood collecting operation.

It will be appreciated that the graduations on the horizontal scale arm 31 are calibrated such that the combined moments exerted by the weights 56 and 57 will balance exactly the moment produced on the inclined lever arm 29 by the support assembly 25 and a load having a total weight equal to that indicated by the pointer 69. This total weight comprises the predetermined known weights of the plastic blood pack 12 and the anticoagulant medium previously introduced therein, in addition to the weight of any blood collected in the pack 12. Normally, the operator will use a suitable conversion table which indicates the correct total weight setting necessary for collection of a predetermined quantity of blood in a given pack 12. Thus, when the desired quantity of blood has accumulated in the blood pack 12, the moment produced by the total weight on the inclined lever arm 29 will overcome that provided by the weights 56 and 57. Accordingly, the scale arm 28 will rotate clockwise about the pivot pin 27 into the position shown in FIG. 6. The resultant movement of the nip 32 with respect to the stationary front block portion 21 pinches and closes the flexible tubing 13 thereby preventing further blood transfer and terminating the collection process.

As the scale lever 28 moves between the positions shown in FIGS. 1 and 6, there is an increase in the length of the moment arm for the force applied by the support assembly 35 which length is determined by the horizontal distance between the pivot pin 27 and the knob 38. Conversely, the lengths of the moment arms for the forces exerted by the weights 56 and 57 as determined by the horizontal distances thereof from the pivot pin 27 are decreased. Thus, there is an increase of torque in the clockwise direction. This increased torque in addition to the mechanical advantage provided by the substantially different radii of action of the knob 38 and nip 32 from the pivot pin 27 insure positive closure of the tubing 13.

Adjustment of the selector weight 57 is easily accomplished by pushing upward on the exposed end 68 of the release pin 63. This forces the release pin 63 upward and eliminates engagement between the teeth 66 and the notches 67 and facilitates free longitudinal movement of the selector weight 57 on the horizontal lever arm 31. However, after attainment of a desired longitudinal position and release of the pin 63 the compression spring 64 again urges the teeth 66 into engagement with the aligned set of notches 67 to inhibit further longitudinal movement of the selector weight 57. The use of a plurality of engaging teeth 66 on the pin 63 improves accuracy by enhancing the locational stability of the selector weight 57. Furthermore, the concealment of the release mechanism within the selector weight 57 and location of the actuator pin end 68 in the weight's bottom surface 62 reduce the likelihood of undesired readjustment of the selector weight 57 by unauthorized personnel.

During the collection process, the electrically energized motor 45 produces rotation of the eccentric shaft 46. The resultant forces exerted between the shaft 46 and the mechanically coupled arched portion 43 produce a rocking movement of the cradle pan 36 between the positions shown dotted in FIG. 1. This rocking motion continuously agitates the blood and anticoagulant contents of the blood pack 12 insuring thorough mixing thereof. Thus, the requirement for manual manipulation of the pack during the collection process is eliminated.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, although described in connection with the preferred blood collection application, it will be obvious that the control device 11 could be used for other purposes including the transfer of therapeutic fluids from a vessel to a patient. In that case the lever arm 28 would be modified such that the inclined arm 29 retained the weights 56 and 57 and the horizontal arm 31 supported a fluid supply vessel. In such an arrangement, the selected weight would be adjusted so as to produce automatic actuation of the scale lever 28 and termination of the fluid transfer process after a predetermined quantity of fluid had been removed from the supply vessel. Also, drive mechanisms other than an electrical motor could be used to produce movement of the cradle pan 36. It is, therefore, to be understood that within the scope of the appended claims the invention can be practiced otherwise than as specifically described.

Claims

I claim:

1. Therapeutic fluid flow control apparatus of the type including a stationary support, a two-arm lever movable thereon about a pivot point, one arm of the lever adapted to support a fluid-collecting closed container having a length of flexible tubing for delivering fluid thereto, a counterbalance on the other lever arm, tube holding means for supporting the flexible tubing in a fixed position with respect to said stationary support and said lever, and pinch means adapted to pinch closed the flexible tubing in response to relative movement between said stationary support and said lever; the improvement to which comprises:

a selector weight supported by and slidable on said other lever arm, said selector weight having top, bottom and side surfaces and defining a central cavity communicating with an opening in said bottom surface;

a plurality of graduated stops on said other lever arm adapted for selective engagement with said selector weight so as to fix the longitudinal position thereof on said other lever arm; and

a releasable biasing means for preventing relative movement between said selector weight and said other lever arm, said releasable biasing means being completely recessed within said selector weight cavity so as to be substantially hidden from view and manually operable only through said opening in said bottom surface to permit relative movement between said selector weight and said other lever arm.

2. Therapeutic fluid flow control apparatus according to claim 1 wherein said releasable biasing means comprises release means disposed in said cavity and adapted for manual actuation through said opening to deactivate said biasing means and allow said relative movement between said selector weight and said other lever arm.

3. Therapeutic fluid flow control apparatus according to claim 2 wherein said graduated stops comprise longitudinally disposed notches in said other lever arm, said releasable biasing means comprises a pin member slidably mounted within said cavity in said selector weight, said cavity being defined by a bore terminating in said bottom surface of said selector weight so as to expose an end of said pin member reforming said release means, said pin member having projection means adapted for selective engagement with said notches, and said releasable biasing means further comprising a spring member biasing said pin member downward and said projection means into engagement with said notches.

4. Therapeutic fluid flow control apparatus according to claim 3 wherein said projection means comprises a plurality of teeth spaced for simultaneous engagement with said notches in said other lever arm.

5. Blood collection apparatus comprising:

movable support means adapted to hold a blood collecting closed container connected to a blood donor by a flexible tubing, scale means for indicating the weight of blood collected in the closed container;

an electrically energizable drive means coupled to said movable support means and adapted upon energization to produce movement thereof and agitation of the fluid content of the closed container;

closure means adapted to automatically interrupt blood flow by closing the flexible tubing in response to an indication by said scale means that a predetermined weight of blood has been collected in the closed container; and

wherein said scale means comprises a two-arm lever pivotally mounted on a stationary support, said movable support means is attached to one arm of the lever and is movable with respect thereto, a counterbalance is attached to the other lever arm, and said closure means comprises pinch means adapted to pinch closed the flexible tubing in response to a predetermined relative movement between said stationary support and said lever.

6. Blood collection apparatus according to claim 5 wherein said movable support means comprises a cradle attached to said one lever arm by a yoke member adapted to support the closed container, and said drive means comprises an electric motor and drive shaft operatively coupled between said cradle and said yoke member and adapted upon energization to produce movement of said cradle so as to agitate the blood content of the closed container.

7. Blood collection apparatus according to claim 6 including electrical leads connected to said electric motor, said leads terminating with a plug adapted for connection to a source of electrical power and having an intermediate portion attached to said stationary support.

8. Blood collection apparatus according to claim 6 including a selector weight supported by and slidable on said other lever arm, and a plurality of graduated stops on said other lever arm adapted for selective engagement with said selector weight so as to fix the longitudinal position thereof on said other lever arm.

9. Therapeutic fluid flow control apparatus according to claim 8 including a releasable biasing means for inhibiting relative movement between said selector weight and said other lever arm.

10. Therapeutic fluid flow control apparatus according to claim 9 wherein said releasable biasing means is substantially enclosed by said selector weight so as to be substantially hidden from view.

11. Therapeutic fluid flow control apparatus according to claim 10 wherein said releasable biasing means comprises release means disposed in the bottom surface of said selector weight and adapted upon actuation to deactivate said biasing means and allow uninhibited relative movement between said selector weight and said other lever arm.

12. Therapeutic fluid flow control apparatus according to claim 11 wherein said graduated stops comprise longitudinally disposed notches in said other lever arm, said releasable biasing means comprises a pin member slidably mounted within a bore in said selector weight, said bores terminating in the bottom surface of said selector weight, said bores terminating in the bottom surface of said selector weight so as to expose an end of said pin member forming said release means, said pin member having projection means adapted for selective engagement with said notches, and said releasable biasing means further comprising a spring member biasing said pin member downward and said projection means into engagement with said notches.

13. Blood collection apparatus according to claim 12 including a selector weight supported and slidable on said other lever arm, and a plurality of graduated stops on said other lever arm adapted for selective engagement with said selector weight so as to fix the longitudinal position thereof on said other lever arm.

14. Therapeutic fluid flow control apparatus according to claim 13 wherein said projection means comprises a plurality of teeth spaced for simultaneous engagement with said notches in said other lever arm.