Method for detection of leakage of blood

• US 5,670,050 A
• Filed: 11/17/1995
• Issued: 09/23/1997
• Est. Priority Date: 02/13/1995
• Status: Expired due to Term

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Aksys Ltd.
• Inventors: Faehnrich, Richard, Brose, Tom L., Blasko, John A.
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US08/560,335
• Time in Patent Office: 676 Days
• Field of Search: 210/646, 210/739, 210/745, 210/85, 210/96.2, 210/929, 604/4, 604/65, 356/39, 356/40, 356/42, 356/432, 356/433, 356/434, 356/435, 356/436, 356/440
• US Class Current: 210/646
• CPC Class Codes: A61L 2/04 Heat A61L2/08 takes precedence
• CPC Class Codes: A61L 2/18 Liquid substances or solutions comprising solids or dissolved gases
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1607 before use, i.e. upstream of dialyser
• CPC Class Codes: A61M 1/1609 after use, i.e. downstream of dialyser
• CPC Class Codes: A61M 1/1649 with pulsatile dialysis fluid flow
• CPC Class Codes: A61M 1/165 with a dialyser bypass on the dialysis fluid line
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/1658 Degasification
• CPC Class Codes: A61M 1/166 Heating for sterilisation A61M1/1686
• CPC Class Codes: A61M 1/1662 with heat exchange between fresh and used dialysate
• CPC Class Codes: A61M 1/1666 by dissolving solids
• CPC Class Codes: A61M 1/1668 Details of containers
• CPC Class Codes: A61M 1/1672 using membrane filters, e.g. for sterilising the dialysate
• CPC Class Codes: A61M 1/1682 both machine and membrane module, i.e. also the module blood side
• CPC Class Codes: A61M 1/1684 Checking the module characteristics before reuse
• CPC Class Codes: A61M 1/1686 by heat
• CPC Class Codes: A61M 1/1688 with recirculation of the sterilising fluid
• CPC Class Codes: A61M 1/169 using chemical substances
• CPC Class Codes: A61M 1/1692 Detection of blood traces in dialysate
• CPC Class Codes: A61M 1/1694 : with recirculating dialysing liquid
• CPC Class Codes: A61M 1/288 : Priming priming in extracorporeal blood circuits A61M1/3643
• 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 1/3465 : using dialysate as substitution fluid
• CPC Class Codes: A61M 1/3468 : using treated filtrate as substitution fluid
• CPC Class Codes: A61M 1/3609 : Physical characteristics of the blood, e.g. haematocrit, urea
• CPC Class Codes: A61M 1/3622 : with a cassette forming partially or totally the blood circuit
• CPC Class Codes: A61M 1/36224 : with sensing means or components thereof
• CPC Class Codes: A61M 1/36226 : Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362263 : Details of incorporated filters
• CPC Class Codes: A61M 1/3626 : Gas bubble detectors
• CPC Class Codes: A61M 1/3627 : Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 1/3629 : degassing by changing pump speed, e.g. during priming
• CPC Class Codes: A61M 1/3639 : Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 : Pressure isolators
• CPC Class Codes: A61M 1/3643 : Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 : Mode of operation
• CPC Class Codes: A61M 1/3646 : Expelling the residual body fluid after use, e.g. back to the body
• CPC Class Codes: A61M 1/3647 : with recirculation of the priming solution
• CPC Class Codes: A61M 1/3649 : using dialysate as priming or rinsing liquid
• CPC Class Codes: A61M 1/365 : through membranes, e.g. by inverted trans-membrane pressure [TMP]
• CPC Class Codes: A61M 2205/12 : with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/15 : Detection of leaks
• CPC Class Codes: A61M 2205/17 : with redundant control systems
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/3317 : Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3324 : PH measuring means
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3344 : Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3382 : Upper level detectors
• CPC Class Codes: A61M 2205/3386 : Low level detectors
• CPC Class Codes: A61M 2205/502 : User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/505 : Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: A61M 2205/6072 : Bar codes
• CPC Class Codes: A61M 2205/705 : Testing of filters for leaks blood in dialysate A61M1/1692
• CPC Class Codes: A61M 2205/707 : Testing of filters for clogging
• 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
• CPC Class Codes: A61M 2206/11 : Laminar flow
• CPC Class Codes: A61M 2230/65 : Impedance, e.g. conductivity, capacity
• CPC Class Codes: A61M 39/16 : having provision for disinfection or sterilisation A61M39/143 takes precedence; methods or apparatus for disinfection or sterilisation A61L2/00
• CPC Class Codes: B01D 2311/04 : Specific process operations in the feed stream; Feed pretreatment
• CPC Class Codes: B01D 2311/10 : Temperature control
• CPC Class Codes: B01D 2311/25 : Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
• CPC Class Codes: B01D 2311/2626 : Absorption or adsorption
• CPC Class Codes: B01D 2321/04 : Backflushing
• CPC Class Codes: B01D 2321/16 : Use of chemical agents
• CPC Class Codes: B01D 2321/32 : By heating or pyrolysis
• CPC Class Codes: B01D 61/02 : Reverse osmosis; Hyperfiltration ; Nanofiltration
• CPC Class Codes: B01D 61/025 : Reverse osmosis; Hyperfiltration
• CPC Class Codes: B01D 61/04 : Feed pretreatment
• CPC Class Codes: B01D 61/12 : Controlling or regulating
• CPC Class Codes: B01D 61/32 : Controlling or regulating
• CPC Class Codes: B01D 65/022 : Membrane sterilisation
• CPC Class Codes: B01D 65/102 : Detection of leaks in membranes
• CPC Class Codes: B01D 65/104 : Detection of leaks in membrane apparatus or modules
• CPC Class Codes: C02F 1/441 : by reverse osmosis
• CPC Class Codes: F16K 17/0453 : the member being a diaphragm
• CPC Class Codes: Y10S 210/929 : Hemoultrafiltrate volume measurement or control processes
• CPC Class Codes: Y10S 215/03 : Medical
• CPC Class Codes: Y10T 137/7722 : Line condition change responsive valves
• CPC Class Codes: Y10T 137/7794 : With relief valve
• CPC Class Codes: Y10T 137/7796 : Senses inlet pressure
• CPC Class Codes: Y10T 137/7799 : Liquid transfer

Abstract

A method for detecting the presence of blood in a dialysate solution is disclosed. The method provides for certain measurement of light intensity passing through solutions both before and during the dialysis session. Before dialysis is commenced, measurements are made of the intensity of light passing through a chamber containing a control dialysate solution that is free of blood. The light source is a first condition. The light source'"'"'s state is changed from a first condition to a second condition different from the first condition. Next, a second measurement of the intensity of light is made. The first and second measurements are stored. During dialysis, the method continues with the following steps: conducting a third measurement of the intensity of light of the light source that passes though the chamber, the chamber containing dialysate solution that may contain the patient'"'"'s blood, with the light source in the first condition. Next, the state of the light source is changed from the first condition to the second condition. A fourth measurement of the intensity of light passing through the solution is made. A suitable processor calculates an attenuation coefficient indicative of the presence of blood in the dialysate solution during dialysis from the first, second, third and fourth measurements.

Claims

1. A method of detecting the presence of blood during dialysis treatment of a patient in a dialysate solution, said solution having been passed through a dialyzer during dialysis of a patient'"'"'s blood, comprising the steps of:

(a) prior to said dialysis treatment

conducting a first measurement of the intensity of light impinging on a photosensitive detector aligned with a light source, said light passing through a chamber containing a control dialysate solution that is free of blood, with said light source in a first condition emitting light of intensity P₀, where P₀ is greater than or equal to zero;

changing the state of said light source from a first condition to a second condition different from said first condition;

conducting a second measurement with said photosensitive detector of the intensity of light from said light source that passes through said chamber containing said control dialysate solution, with said light source in said second condition emitting light at an intensity P₁ ≠

P₀, and

(b) during dialysis,

conducting a third measurement with said photosensitive detector of the intensity of light, said light passing through said chamber, said chamber containing dialysate solution that may contain the patient'"'"'s blood is said dialzyer is in a defective condition allowing said patient'"'"'s blood to pass through said dialzyer into said dialysate solution, said light source in said first condition;

changing the state of said light source from said first condition to said second condition;

conducting a third measurement with said photosensitive detector of the intensity of light of said light source that passes through said chamber, said chamber containing dialysate solution that may contain the patient'"'"'s blood is said dialyzer is in a defective condition allowing said patient'"'"'s blood to pass through said dialzyer into said dialysate solution, said light source in said second condition; and

calculating an attenuation coefficient of said intensity of light passing through said chamber indicative of the presence of blood in said dialysate solution during dialysis from said first, second, third and fourth measurements.

2. The method of claim 1, wherein said first condition of said light source is an OFF condition with P₀ =0 and said second condition of said light source is an ON condition with P₁ ≠

0; and

wherein said method further comprises the step of making reference measurements of said light source in said ON and OFF conditions both before and during said dialysis treatment.

3. The method of claim 1, wherein said attenuation coefficient is proportional to the quotient of the difference between said third and fourth measurements divided by the difference between said first and second measurements.

4. The method of claim 1, wherein said first condition of said light source comprises a state in which said light source emits light of said intensity P₀ where P₀ >

0, and wherein said second condition of said light source comprises a state in which said light source emits light of said intensity P₁, where P₁ >

P₀.

5. The method of claim 1, wherein said step of calculation of an attenuation coefficient is performed repeatedly during said dialysis treatment.

6. The method of claim 1, wherein said first condition of said light source comprises an OFF condition in which P₀ =0.