Blood circulation auxiliary device using continuous blood flow pump and diagnosis device for blood circulation state in organism

• US 6,572,530 B1
• Filed: 06/26/2000
• Issued: 06/03/2003
• Est. Priority Date: 12/27/1997
• Status: Expired due to Fees

• Current Assignee: JMS Company Limited
• Original Assignee: JMS Company Limited
• Inventors: Anai, Hirohumi, Oshikawa, Mitsuo, Araki, Kenji
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/582,465
• Time in Patent Office: 1,072 Days
• Field of Search: 606/16-18, 604/6.11, 604/4.01
• US Class Current: 600/17
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 60/104 Extracorporeal pumps, i.e. the blood being pumped outside the patient's body
• CPC Class Codes: A61M 60/216 including a rotating member acting on the blood, e.g. impeller
• CPC Class Codes: A61M 60/411 generated by an electromotor

Abstract

A blood circulation assisting device using a continuous flow blood pump (1) for blood feeding assistance to remove blood through a blood removing pipe (2) and drive out blood at a predetermined flow rate through a blood feeding pipe (3). The blood circulation assisting device includes a current measuring unit (7) for measuring current flowing through a motor (4) driving the pump (1) in order to use the current as data corresponding to a blood flow rate through the continuous flow blood pump (1) and an amplitude detection unit (8) for detecting, from an output of the current measuring unit (7), the amplitude of fluctuation of current flowing through the motor (4) in order to use the amplitude as data corresponding to a flow rate amplitude due to flow rate fluctuation. The amplitude of this fluctuation is divided by an average current value and output as an amplitude index. By controlling the speed of the motor (4) so that the amplitude index, which is the output of the amplitude detection unit (8), is within a predetermined value, a blood feeding assistance is kept in an optimum state matching a blood circulation state in an organism.

Claims

1. A blood circulation assisting device comprising:

a continuous flow blood pump comprising a non-displacement-type pump for blood feeding assistance,

a motor for driving said continuous flow blood pump,

a blood removing pipe having one end attachable to a blood removal site in an organism and the other end connected to an inflow portion of said continuous flow blood pump,

a blood feeding pipe having one end attachable to a blood feed site in the organism and the other end connected to an outflow portion of said continuous flow blood pump,

wherein blood is removable via said blood removing pipe and drivable out via said blood feeding pipe by said continuous flow blood pump so as to attain a predetermined flow rate,

said blood circulation assisting device further comprising

flow rate detection means for directly or indirectly obtaining data corresponding to a blood flow rate flowing through said continuous flow blood pump,

fluctuation amplitude detection means for obtaining, from an output of said flow rate detection means, data corresponding to a fluctuation amplitude of the flow rate,

specific point detection means for detecting at least one of a t-point and a s-point, the t-point and the s-point being a starting point and an end point, respectively of a range where the fluctuation amplitude of the flow rate shows a negative correlation with a speed of the motor, and

adjusting means for adjusting a motor speed based on an output of said specific point detection means.

2. The blood circulation device according to claim 1, wherein said flow rate detection means is configured so that an output corresponding to the flow rate is obtainable by measuring a current consumption or a power consumption value of the motor.

3. The blood circulation assisting device according to claim 2, wherein said fluctuation amplitude detection means detects a mean output and an output fluctuation amplitude of said flow rate detection means at predetermined time intervals and outputs an amplitude index that is obtained by dividing the fluctuation amplitude with the mean output.

4. The blood circulation assisting device according to claim 3, wherein said adjusting means comprises control means for controlling the motor speed according to the output of said fluctuation amplitude detection means so that the amplitude index is within a predetermined range.

5. The blood circulation assisting device according to claim 2, wherein said specific point detection means is capable of detecting the t-point and the s-point, and the control means controls the motor speed so as to correspond to the speed between near the t-point and near the s-point.

6. The blood circulation assisting device according to claim 1, wherein said flow rate detection means is configured so that an output corresponding to the flow rate is obtained by using a flow sensor disposed near said continuous flow blood pump.

7. The blood circulation assisting device according to claim 1, wherein said fluctuation amplitude detection means detects a maximum value and a minimum value of the output of said flow rate detection means at predetermined time intervals and outputs the maximum value and the minimum value.

8. The blood circulation assisting device according to claim 1, wherein said fluctuation amplitude detection means outputs the fluctuation amplitude that is a difference between a maximum value and a minimum value of the output of said flow rate detection means.

9. The blood circulation assisting device according to claim 8, wherein said adjusting means comprises control means for controlling the motor speed according to the output of said fluctuation amplitude detection means so that the amplitude is within a predetermined range.

10. The blood circulation assisting device according to claim 9, wherein said control means is capable of identifying the t-point or s-point by forcing the motor to change its speed temporarily so as to cause the fluctuation amplitude to vary and detecting the correlation between the fluctuation amplitude of the flow rate and the speed of the motor based on the change of the fluctuation amplitude.

11. The blood circulation assisting device according to claim 1, wherein

said specific point detection means comprises display means for displaying the output of said fluctuation amplitude detection means, and

said adjusting means comprises means for manually operating and adjusting a speed of the motor driving said pump.

12. The blood circulation assisting device according to claim 1, wherein said adjusting means comprises control means for controlling automatically motor speed so as to be in a predetermined relation to the motor speed at the detected t-point and/or s-point.

13. The blood circulation assisting device according to claim 12, wherein said control means controls the motor so as to have a speed corresponding to the t-point or near the t-point.

14. The blood circulation assisting device according to claim 12, wherein said control means controls the motor so as to have speed corresponding to the s-point or near the s-point.

15. A diagnosis device for blood circulation state comprising said blood circulation assisting device according to claim 1, wherein, when said device is attached to an organism, the speed of the motor is changed, a t-point at which circulation assistance by said pump changes from partial to total assistance is detected based on an output change of said flow rate amplitude detection means caused by the change of the motor speed, and an inflow state at a blood inflow port and/or filling state of a heart are detected based on the flow rate amplitude at the detected t-point or near the t-point.

16. A methyl for diagnosing an organism, wherein the device according to claim 15 is attached to the organism to diagnose a blood circulation state.

17. A diagnosis device for blood circulation state comprising said blood circulation assisting device according to claim 1, wherein, when said device is attached to an organism, the speed of the motor of said continuous flow blood pump is changed, a t-point at which circulation assistance by said pump changes from partial to total assistance is detected based on an output change of said flow rate amplitude detection means caused by the change of the motor speed, the speed change of the motor corresponding to the detected t-point or near the t-point is detected, and a change of circulation state in the organism is detected with the speed change.

18. The diagnosis device for blood circulation state according to claim 17, wherein, when the speed of the motor corresponding to the t-point or near the t-point increases, unchanged blood pressure is judged as an increase of venous return or unchanged venous return is judged as an increase of blood pressure.

19. The diagnosis device for blood circulation state according to claim 17, wherein, when the speed of the motor corresponding to the t-point or near the t-point decreases, unchanged blood pressure is judged as an increase of venous return decrease or unchanged venous return is judged as an increase of blood pressure.

20. The diagnosis device for blood circulation state comprising said blood circulation assisting device according to claim 1, wherein, when said device is attached to an organism, the speed of the motor is changed, an s-point at which a fluctuation of the flow rate amplitude becomes distinctive because a blood inflow port of said blood removing pipe starts sucking on to a wall of the organism is detected based on an output change of said flow rate amplitude detection means caused by the change of the motor speed, and an inflow state at the blood inflow port and/or filling state of a heart are detected based on the flow rate amplitude at the detected s-point or near the s-point.

21. The diagnosis device for blood circulation state comprising said blood circulation assisting device according to claim 1, wherein, when said device is attached to an organism, the speed of the motor is changed, an s-point at which a fluctuation of the flow rate amplitude becomes distinctive because a blood inflow port of said blood removing pipe starts sucking on to a wall of the organism is detected based on an output change of said flow rate amplitude detection means caused by the change of the motor speed, the speed at the detected s-point or near the s-point is detected, and a change of circulation state in the organism is diagnosed with the speed change.

22. A method of assisting blood circulation in an organism, wherein the device according to claim 1 is attached to the organism to assist blood circulation.