Method and apparatus for treating blood

• US 6,083,187 A
• Filed: 09/08/1997
• Issued: 07/04/2000
• Est. Priority Date: 09/09/1996
• Status: Expired due to Fees

• Current Assignee: Kaneka Corporation
• Original Assignee: Kaneka Corporation
• Inventors: Yoshida, Eiichi, Nakayama, Takehisa, Tachibana, Hiroshi, Hamanishi, Yasufumi, Takao, Yoshizumi, Narisada, Masataka
• Primary Examiner(s): Polutta, Mark O.
• Assistant Examiner(s): BIANCO, PATRICIA
• Application Number:
  US08/924,942
• Time in Patent Office: 1,030 Days
• Field of Search: 424/530, 604/4, 210/416.1, 210/97, 210/98, 222/401, 222/402.11
• US Class Current: 604/6.01
• CPC Class Codes: A61M 1/3434 with pre-dilution and post-dilution
• CPC Class Codes: A61M 1/3437 downstream of the filter, e.g. post-dilution with filtrate
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3448 by mechanically linked pumps in both ultra-filtrate and substitution flow line
• CPC Class Codes: A61M 1/3468 using treated filtrate as substitution fluid
• CPC Class Codes: A61M 1/3472 with treatment of the filtrate
• CPC Class Codes: A61M 1/3482 by filtrating the filtrate using another cross-flow filter, e.g. a membrane filter
• CPC Class Codes: A61M 1/3486 Biological, chemical treatment, e.g. chemical precipitation; treatment by absorbents
• CPC Class Codes: A61M 1/3623 Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3646 Expelling the residual body fluid after use, e.g. back to the body
• CPC Class Codes: A61M 2205/7554 with means for unclogging or regenerating filters
• CPC Class Codes: A61M 2205/7581 with means for switching over to a fresh filter on clogging or saturation

Abstract

The invention pertains to a method and apparatus for treating blood. If pressure constraints occur during the execution of blood treatment, the pump flow rates are rapidly decelerated to remove the pressure constraints so that the treating operation will restore the normal state as quickly as possible. After the pressure constraints have been removed, the pump flow rates are restored at a preset acceleration without causing any excessive pressure buildup due to an abruptly increased load. If the pump flow rates immediately after the start of operation of the processor are increased through two stages of acceleration, the target flow rates can be rapidly reached without exerting any abrupt load on the processor and, hence, without causing an excessive pressure buildup.

Claims

1. An apparatus for blood treatment comprising

a collection circuit which includes a blood pump and into which a blood sample is withdrawn by means of said blood pump,

a treatment circuit for performing a treatment on the withdrawn blood sample, and

a return circuit through which the treated blood sample is returned to the patient,

pressure gauges provided in at least one circuit among the collection circuit, the treatment circuit and the return circuit, and

means for controlling the operation of the blood pump by

(i) from the start of the treatment, increasing a flow rate of said blood pump at a preset normal acceleration until a specified target blood flow rate is reached,

(ii) once said target blood flow rate has been reached, operating said blood pump so as to maintain said target blood flow rate,

(iii) reducing said flow rate of said blood pump at a specified deceleration if values of pressure detected by specified pressure gauges among said pressure gauges or values calculated on the basis of said pressure values deviate from respective limiting values to cause pressure constraints during operation of said blood pump to (a) increase said flow rate of said blood pump at said preset normal acceleration or (b) maintain said flow rate of said blood pump at said target blood flow rate, and

(iv) if said pressure constraints are removed, increasing said flow rate of said blood pump at said normal acceleration so that it is reverted to said target blood flow rate,

wherein

the treatment circuit includes an adsorptive blood treatment circuit which includes a plasma separator, a plasma pump and an adsorber, and in which a plasma separated from the blood sample by means of said plasma separator is directed by said plasma pump into said adsorber where unnecessary components are removed from the plasma, and

said apparatus further comprises means for controlling the operation of said plasma pump by

(i) starting said plasma pump after said blood pump rate exceeds a predetermined value,

(ii) increasing a flow rate of said plasma pump at a preset normal acceleration after the start of said plasma pump and until a specified target plasma flow rate calculated based on said flow rate of said blood pump is reached,

(iii) controlling the operation of said plasma pump so as to maintain said target plasma flow rate once it has been reached,

(iv) reducing said flow rate of said plasma pump at a specified deceleration if values of pressure detected by the specified pressure gauges or values calculated on the basis of said pressure values deviate from respective limiting values to cause pressure constraints, and

(v) increasing said flow rate of said plasma pump at said normal acceleration so that it is reverted toward said target plasma flow rate if said pressure constraints are removed.