Automatic priming method

An automatic priming method in which an arterial-side chamber is maintained in a normal position during priming, as in a case of dialysis treatment, and in which forward and backward rotations of a blood pump are employed, and a speed of rotation, in particular, backward rotation, is adjusted to be low, so that air or the like is reliably prevented from entering a dialyzer. The priming method for use in a blood purification circuit in which priming is conducted by supplying physiological saline into a circulation circuit formed by connecting an arterial blood circuit with a venous blood circuit includes filling the venous blood circuit with a priming solution (physiological saline), discharging the priming solution for cleaning the arterial blood circuit, conducting a treatment in a direction opposite to the overflow step, which may be followed by a forward direction re-circulation step, and re-circulating in a forward direction.

TECHNICAL FIELD

The present invention relates to a method of automatically priming a blood purification circuit including a blood purifier connected to a blood circuit.

BACKGROUND ART

In general, before using a blood purification circuit for dialysis, there is performed a treatment of eliminating foreign substances and air existing in the blood circuit by introducing a priming liquid (generally, physiological saline is used) to fill a blood circuit therewith, that is, a priming treatment.

In a conventional dialysis apparatus, physiological saline is used to manually conduct priming of the blood circuit. However, recently, the priming is conducted by using an automatic priming apparatus.

As the automatic priming apparatus, Patent Document 1 discloses the following: that is, an artificial dialysis apparatus including a blood circuit having a dialyzer, which is provided with a blood pump, in which an arterial blood circuit and a venous blood circuit are connected to each other to form a circulation circuit, an overflow tube and an opening and closing means are provided above a drip chamber of the blood circuit, and the blood pump is actuated in a state where the opening and closing means of the tube is opened to allow a priming liquid to circulate through the circuit and the priming liquid is supplied from a priming liquid storage container to the circulation circuit at a predetermined flow rate, thereby discharging a part of the priming liquid from the overflow tube and conducting the priming.

However, in a case where the priming is conducted by this method, air remains in an inlet-side drip chamber. Therefore, there arises a problem in that the drip chamber cannot be filled with the priming liquid (physiological saline).

In order to solve the problem, Patent Document 2 suggests an automatic priming method for a blood purification circuit, in which an arterial-side chamber (corresponding to the inlet-side drip chamber of Patent Document 1 described above) provided in a blood circuit is installed while being directed upside down and priming is conducted. In a case where the method is adopted, at a time of a dialysis treatment performed afterwards, there is required an operation of returning the installation direction to an original direction. Without this operation, it is impossible to perform trapping of bubbles, which is one object of the drip chamber.

Patent Document 1: Japanese Utility Model Examined Publication No. Hei 05-19076

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

In consideration of the conventional technique as described above, it is an object of the present invention to provide an automatic priming method by which priming is conducted while keeping, in the automatic priming, an arterial-side chamber in a normal position as in a case of dialysis treatment, forward and backward rotations of a blood pump are employed, and a speed of rotation, in particular, backward rotation is adjusted (to be relatively low) so that air or the like is reliably prevented from entering a dialyzer and is eliminated.

Means for Solving the Problem

In order to achieve the above-mentioned object, the present invention provides a priming method in which a connection portion1of an arterial blood circuit L1and a connection portion2of a venous blood circuit L2are connected to form a circulation circuit in which a blood pump P1, an arterial chamber C2, a blood purifier (dialyzer) D, and a venous chamber C1are arranged in the stated order, the venous chamber C1being connected to an overflow line O, a side of the venous blood circuit being provided with a valve PV2, the arterial blood circuit L1having a system in which a storage container S for storing a physiological saline S1and a supply pipe K are connected to each other at a branch portion a, the method including: (1) an early injection step for a priming liquid (physiological saline); (2) an overflow step; and (3) a reverse direction re-circulation step, the method being characterized in that, those steps may be followed by a forward direction re-circulation step (valve1and valve2are opened, blood pump P1is operated to rotate forward to supply a priming liquid and while circulation is performed, an excessive liquid is discharged through overflow line O, that is, a step according to claim5), and as needed, (4) a forward direction circulation step is performed.

Note that, the supply pipe K may be provided with a detector E, a valve PV3for opening and closing the supply pipe, and the like. The valves and the blood pump P1may be connected to an operation control portion F for controlling operations of those.

EFFECT OF THE INVENTION

In the present invention, by the above-mentioned priming method, since an installation direction of the chamber is set to that in the normal position, unlike in a case where the chamber is set in an opposite position, there is no problem of forgetting an operation of returning the position of the chamber to the normal position when performing a dialysis treatment. Further, forward and backward rotations of a blood pump are employed, and a speed of rotation, in particular, backward rotation is adjusted (to be relatively low) so that air is reliably prevented from entering a dialyzer.

Moreover, steps from an early injection step to a circulation step can be automatically set by a program in advance. Further, by making a blood circuit as a cassette, an inexpensive circuit can be provided.

DESCRIPTION OF REFERENCE SYMBOLS

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a detailed description will be made of an automatic priming method according to the present invention in an embodiment with reference to the drawings.

(a)FIG. 1(filling of a line from a branch point a to a venous chamber C1with physiological saline) shows an early injection step of filling a venous blood circuit L2with the physiological saline of the present invention. In the step, a blood pump P1is stopped, an overflow line opening and closing means PV1(valve1) and a venous circuit closing means PV2(valve2) are opened. By a drop pressure in a physiological saline storage container S, the physiological saline fills a venous chamber C1through a physiological saline line branch portion a and the venous circuit closing means PV2, and is discharged together with bubbles through an overflow line O and the overflow line opening and closing means PV1.

(b)FIG. 2is a diagram showing a step of cleaning an arterial blood circuit, that is, an overflow step in a forward direction, in which bubbles and the circulating physiological saline in the circuit are discharged through the overflow line O. In the overflow step in the forward direction, the valve1is opened, the valve2is closed (the valve2is closed, so the physiological saline remains in a line from the valve2through an arterial blood circuit L1and a venous blood circuit L2to a branch point a), and the blood pump P1is rotated forward at a preset speed of 100 to 300 mL/min, preferably about 200 mL/min, to send the physiological saline through a chamber C2, thereby allowing the circuit from the branch point a to the chamber C1to be filled with the physiological saline and allowing bubbles in the blood circuit to pass through the overflow line O and the valve1in the stated order to be discharged. In this step, when a speed of the blood pump P1is too low, it takes long, but when the speed thereof is too high, a pressure is applied to the overflow line through which the physiological saline is discharged and there is a risk of the dialyzer being applied with too much pressure. Therefore, the speed is preferably set within a range of 100 to 300 mL/min.

(c)FIG. 3shows a reverse direction re-circulation step of the overflow step. In the overflow step in a reverse direction, both the valves1and2are opened and the blood pump P1is rotated backward at a speed of 10 to 50 mL/min, preferably about 20 mL/min, whereby bubbles accumulating in an upper portion of the arterial chamber C2(and an upper portion of a dialyzer D) are discharged, and at the same time, a priming liquid is passed through the venous chamber C1from the valve2through the blood pump P1, an arterial blood circuit L1, and the venous blood circuit L2, to be flown out of the overflow line O to the valve1. This is because a floating speed of air is higher than a flow rate of the priming liquid (for example, 20 mL/min), and in the arterial chamber C2, a tube of a main line M is longer in a downward direction than a tube of the overflow line O, so the circulated bubbles are not sucked in the main line and are sucked in the overflow line O and flow in the overflow line O.

The speed of the blood pump P1is made 10 to 50 mL/min. This is because by making the speed of the blood pump P1lower than the floating speed of air expelled from the arterial chamber and flowing into the venous chamber, re-circulation of air is prevented. When the speed of the blood pump P1is too high, recontamination of air is induced. When the speed thereof is too low, it takes too long time to expel the air.

FIG. 4shows a structure of the venous chamber C1. During the step of the item (c) for priming, a space above a physiological saline S which is stored is restricted at a distal end position of the overflow line O to be secured. A floating speed of bubbles in the physiological saline (priming liquid), that is, bubbles discharged from the arterial chamber is higher than a suction speed (blood pump speed 10 to 50 mL/min) into the main pipe M immersed in the physiological saline, so the bubbles are not sucked into the main pipe M. Therefore, the bubbles float on a border surface G, that is, a liquid surface in the space to be discharged through the overflow line O positioned on the border surface G.

(d)FIG. 5is an explanatory diagram showing a forward direction circulation step, which is embodied as occasion needs. In the circulation step, the valve1is closed and the valve2is opened. The blood pump P1is rotated forward and the circulation is performed in the circuit. The circulation is performed from a line below the venous chamber C1through the valve2, the venous blood circuit L2, and the arterial blood circuit L1to the blood pump P1, further through the arterial chamber C2and the dialyzer D to the venous chamber C1. Fine bubbles existing in a line from a lower portion of the venous chamber C1to an upper portion the arterial chamber C2accumulate in the upper portion of the arterial chamber C2. Fine bubbles existing in a line from a lower portion of the dialyzer D to the upper portion of the venous chamber C1accumulate in the venous chamber C1.

In this step, the fine bubbles accumulate in the chambers (C1and C2). When the bubbles are in the line, thrombi are liable to be formed during the dialysis. It is required to prevent the thrombi from being formed and bubbles from entering a human body. The accumulating bubbles can be discharged by repeating the reverse direction re-circulation step and the forward direction circulation step.

According to the present invention, the following means may be added to the above-mentioned steps.

(e) In an apparatus according to claim1, a supply pipe K is provided with a liquid shortage detector E and a supply pipe opening and closing valve PV3(valve3).

(f) The opening and closing valves1,2, and3and the blood pump P1are connected to an operation control portion F for controlling operations of those.

(g) After the step of the item (c), the valve1and the valve2are opened and the blood pump P1is operated to rotate forward, the priming liquid is supplied, and while circulation is performed, an excessive liquid is discharged through the overflow line O.

(h) The supply pipe K is provided with the liquid shortage detector E, liquid shortage is detected in the step of the item (c), and at the same time, the step proceeds to the step of the item (d).

(i) The supply pipe K is provided with the liquid shortage detector E, the liquid shortage is detected in the step of the item (g), and at the same time, the step proceeds to the step of the item (d).

(j) The supply pipe K is provided with the supply pipe opening and closing valve PV3(valve3).

Those additional steps may be appropriately combined with each of the above-mentioned steps.

By the priming method according to the present invention as described above, an operation of setting an installation direction of the chambers is not required. Further, it is possible to reliably conduct the priming for the entire blood circuit, to eliminate foreign substances and bubbles, and to simplify a dialysis operation.