Apparatus for measuring aggregation rate of whole blood red blood cells

• US 4,822,568 A
• Filed: 06/16/1986
• Issued: 04/18/1989
• Est. Priority Date: 03/28/1986
• Status: Expired due to Fees

• Current Assignee: Minoru Tomita
• Original Assignee: Minoru Tomita
• Inventors: Tomita, Minoru
• Primary Examiner(s): Richman, Barry S.
• Assistant Examiner(s): Johnston, Jill
• Application Number:
  US06/874,558
• Time in Patent Office: 1,037 Days
• Field of Search: 422/73, 422/110, 436/69, 436/70, 356/39, 128/633, 128/637, 128/691
• US Class Current: 422/73
• CPC Class Codes: G01N 15/05 in blood
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/56

Abstract

A whole blood aggregometer of red blood cells (RBC) consists of a transparent tube containing freshly drawn heparinized blood, and a densitometer head which is attached to the tube. The densitometer head consists of a light source and a light detector to monitor changes in optical density of the blood in the tube. The blood in the tube is first subjected to rapid flow with a solenoid, so that the wall shear rate of the blood approximates to 500 s^-1. The shear gives rise to a rapid increase in optical density of the blood due to dispersion of the blood corpuscles. The blood is then brought abruptly to a full stop. After the flow has stopped, the densitometer head reveals a gradual decrease in optical density in association with RBC aggregate formation. The resultant pattern is termed as an "RBC aggregogram". The RBC aggregogram exhibits a quasi-exponential decay in its initial part, which is followed by an asymptotical decrease. A mathematical procedure is employed to calculate the rate constant of the initial decrease from the two values on the RBC aggregogram at 10 s and 20 s. The rate constant k₁₀ is 0.192+0.028 for feline blood, and 0.129+0.012 for human blood. The RBC aggregation rate varies linearly with the hematocrit below 40%.

Claims

1. An apparatus for measuring the aggregation rate of whole blood red blood cells, comprising:

a tube through which blood can flow;

means for varying flow rate of the blood in said tube;

means, at one side of said tube, for transmitting light through the tube and the blood therein;

means for detecting light from said light transmitting means after the light has been transmitted through the blood in the tube, and for producing signals representative of changes in optical density of the light so detected at different flow rates of the blood;

means for receiving said signals to determine said aggregation rate;

said tube comprising a cubital vein in an extracorporeal circulatory system;

said detecting means comprising a light detector of a densitometer; and

said densitometer being connected to a voltage comparator switch of a warning device.

2. The apparatus of claim 1, wherein said extracorporeal system is a renal dialysis.

3. The apparatus of claim 1, wherein said extracorporeal circulatory system is an artificial cardiopulmonary apparatus.

4. An apparatus for measuring the aggregation rate of whole blood red blood cells, comprising:

a tube through which blood can flow;

a syringe for containing a sample of the blood, the syringe being connected to said tube and in communication with the interior of said tube, said syringe having a movable piston therein to effect flow of blood in said tube;

a solenoid having a plunger connected to said piston for moving said piston along said syringe;

electrical circuit means for controlling supply of electrical power to said solenoid for controlling the rate of movement of said piston in one direction;

means for bringing said piston to a full stop after movement thereof in said one direction;

means, at one side of said tube, for transmitting light through the tube and the blood therein;

means for detecting light from said light transmitting means after the light has been transmitted through the blood in the tube, and for producing signals representative of changes in optical density of the light so detected at a controlled flow rate of the blood and when the flow of blood is stopped by said bringing said piston to said full stop;

means for receiving said signals to determine the aggregation rate of the red blood cells; and

said light transmitting means comprising a semiconductor laser.

5. An apparatus for measuring the aggregation rate of whole blood red blood cells, comprising:

a tube through which blood can flow;

a syringe for containing a sample of the blood, the

syringe being connected to said tube and in communication with the interior of said tube, said syringe having a movable piston therein to effect flow of blood in said tube;

a solenoid having a plunger connected to said piston for moving said piston along said syringe;

electrical circuit means for controlling the supply of electrical power to said solenoid for controlling the rate of movement of said piston in one direction;

means for bringing said piston to a full stop after movement thereof in said one direction;

means, at one side of said tube, for transmitting light through the tube and the blood therein;

means for detecting light from said light transmitting means after the light has been transmitted through the blood in the tube, and for producing signals representative of changes in optical density of the light so detected at a controlled flow rate of the blood and when the flow of blood is stopped by said bringing said piston to said full stop;

means for receiving said signals to determine, the aggregation rate of the red blood cells; and

a spring biasing said piston in an opposite direction, said solenoid moving said piston in said one direction and said spring returning said piston in said opposite direction.

6. The apparatus of claim 5, wherein said syringe is disposed horizontally above said solenoid, and said spring is connected to said plunger.