Conventionally, hemodialysis apparatuses for performing treatments requiring extracorporeal circulation of the blood of patients have been used, for example, for patients with renal failure, drug-addicted people, etc. This hemodialysis apparatus includes a blood processing machine for bringing blood into contact with dialysate via a semipermeable membrane to purify the blood, a blood circuit connected to a blood flow path of the blood processing machine, and a dialysate circuit connected to a dialysate flow path of the blood processing machine.
The blood circuit includes an arterial line through which blood is led from a patient to the blood flow path of the blood processing machine, a venous line through which blood is led from the blood flow path of the blood processing machine back to the patient, and drip chambers attached to the arterial line and the venous line. The blood circuit further includes a line for medication infusion, etc. On the other hand, the dialysate circuit includes a dialysate supply line for supplying dialysate to the dialysate flow path of the blood processing machine, and a dialysate drain line for draining dialysate from the dialysate flow path of the blood processing machine. Furthermore, the hemodialysis apparatus is connected also with pressure monitor lines for monitoring the internal pressures of the circuits, and other components.
As described above, the hemodialysis apparatus is composed of many components. Extreme care should be taken to connect these components and examine the hemodialysis apparatus. Specifically, since, in particular, the blood circuit is connected to a blood vessel of a patient, abnormal conditions, such as disconnection, may cause the following accidents: air may be drawn into the blood circuit so as to be mixed into the body of the patient; and blood in the blood circuit may leak out so that the patient may experience blood loss.
These accidents must be prevented before they occur. Therefore, when treatment is performed, health care workers have examined a blood circuit for abnormal conditions with the greatest care. This examination has placed great physical and mental stress on the health care workers.
To address the above-mentioned problem, hemodialysis apparatuses described in PATENT DOCUMENTS 1 and 2 can automatically detect abnormal conditions in a blood circuit in order to perform safe treatment while reducing stress on health care workers. A blood circuit of the hemodialysis apparatus of PATENT DOCUMENT 1 is connected with a priming fluid reservoir for use in priming. The priming fluid reservoir is disposed above pressure detectors attached to pressure monitor lines. While an arterial line and lines of a dialysate circuit are interrupted, the pressure difference between the priming fluid reservoir and the pressure detector is detected, thereby detecting abnormal conditions in the blood circuit based on the pressure difference.
In the hemodialysis apparatus of PATENT DOCUMENT 2, a pressure monitor line of a blood circuit is connected with an air pump. While the blood circuit is closed, air is pumped to the blood circuit by the air pump to detect the pressure of the blood circuit, thereby detecting abnormal conditions in the blood circuit based on the detected value.
PATENT DOCUMENT 1: Japanese Patent Publication No. 2005-218709
PATENT DOCUMENT 2: Japanese Patent Publication No. 2002-95741