MXPA98002396A - Method to test the integrity of dialyzed before usa - Google Patents

Abstract

The present invention includes a method and apparatus for testing the integrity of a dialysate before use. The dialysate is tested in the same way as when used in dialysis treatment. The dialysate is prepared in the normal way. The arterial blood line is held while the venous line is vented to the atmosphere. The ultrafiltrate flow rate through the dialysate is increased until an index is achieved, so that the blood that passes through will be filtered. Dialysate is controlled in terms of pressure increases. If the pressure does not increase the test fal

Description

METHOD TO TEST THE INTEGRITY OF THE DIALYZER BEFORE USE FIELD OF THE INVENTION Herein is described a method for the detection of blood leaks in a dialyzer before use. More specifically, a method and apparatus using current dialysis treatment equipment is presented, to automatically test a dialyzer membrane for leak integrity prior to reuse of the dialysate. BACKGROUND OF THE INVENTION Hemodialysis is a form of treatment for chronic renal failure. In hemodialysis, the patient's blood is purified outside the body in an artificial kidney called a dialyzer containing a compartment for the blood and a compartment for the dialysate, separated by a membrane. The total surface area of? ß. membrane measures 1-2 square meters. During a hemodialysis treatment, the patient's blood is allowed to flow from one side of the membrane and the dialysis fluid through the other. At the beginning of the dialysis treatment, the level of waste product in the blood is high, while the dialysis fluid does not contain said products. Because the waste products are usually dissolved substances of small size they are able to pass from the blood, through the membrane, into the dialysis fluid. This movement continues until there is an equitable level of substance on both sides of the membrane. In order to remove excess water from the blood, it is necessary to create a pressure difference between the blood side and the dialysis fluid side of the membrane. The process to create this pressure between both sides of the membrane is called ultrafiltration. Hemodialysis with the use of disposable dialyzers became a widely used method to perform the dialysis treatment. An example of such a widely used dialyzer is the type of hollow fiber dialyzer, which has a blood compartment composed of a packet of hollow fibers and a dialysate compartment formed by a sleeve surrounding the fiber packet. Treatment with the use of disposable dialyzers, however, can be fraught with extremely high costs. Efforts to reduce costs related to dialysis treatment concluded that hollow fiber dialyzers can be reused, provided they are properly cleaned of bacterial matter, proteins and other particulate matter. It is understandable that the cleaning process, as well as the use of the dialyzer, can cause damage to the dialyzer. The clean dialyzer should be tested to verify that there is no leakage between the blood and dialysate compartment caused by broken fibers or seals. The importance of ensuring the integrity of a dialyzer before its use or reuse is understandable. If there is a leakage of integrity in the limbs, one can either infuse non-sterile dialysate into the patient or lose blood in the dialysate flow, depending on the pressure gradients of the dialyzer. As indicated in the prior art, special machines have been invented to prepare dialysers for reuse, which often include test mechanisms to check the leakage and dialyzer capacity. For example, U.S. Patent 4,846,970 to Bertelsen et al. presents a cross-flow membrane test unit. The device of this invention has a lower cell body, an upper cell body and a pair of laterally spaced O-rings that form a seal between them. The lower cell body is provided with a feeding spacer cavity and the upper cell body is provided with a permeable transport cavity. A test sample of the membrane is placed on the machine and the flow dynamics of a full-scale dialysis system are simulated.

United States Patents 4, 444, 596 and 4, 444,597 by Gortez et al. presents an automatic method and apparatus for cleaning and disinfecting dialyzers before reuse, which have multiple stations capable of cleaning a variety of dialyzers. By using the independent machine of this invention, the dialyzer, the station that cleans the dialyzer and the patient are identified and the identifications are stored in the memory. A machine automatically sequences the cleaning procedures, and the sequence is selectively controlled using test procedures that measure the indications of the possibility of reusing the dialyzer. The machine's test procedures include a blood leak test, a pressure leak test and an ultrafiltration rate test. U.S. Patent 4, 449,392 to Husch teaches a device for testing sterile filters. The filter checking device of this invention includes a filter housing having an air inlet and outlet and receiving the filter. An inlet hose connects to the air inlet. An inlet valve for the inlet line is controlled to produce a constant air pressure and constant rise therein, and an electronic pressure sensor monitors the air pressure therein.

An electronic evaluation and control circuit has a time switch, an adjustable threshold device and a maximum pressure detector and controls the inlet valve, a vent valve connected to the inlet hose and a recording mechanism. The air pressure in the inlet line increases until it reaches a predetermined pressure. The valve is then closed for the period of time set in the time switch. Thereafter, air is again supplied to the inlet tube until the maximum pressure sensor no longer detects pressure increase. U.S. Patent 5,064,529 to Hirayama et al. presents an apparatus to test the membrane filters. The membrane filter testing apparatus of this invention uses a control circuit to increase the pressure on the prime side of a membrane filter. The control circuit is fixedly accommodated in a housing and moistened with a liquid. The pressure on the prime side is increased with gas at a predetermined speed. The pressure of the prime side is verified at the end of a previously determined period of time to see if it is within a specified range. Although the prior art has made progress in how to reduce the costs associated with dialysis treatment by inventing machines that test the integrity of the dialyzer prior to reuse, the machines themselves are expensive. It requires an operator to program the machine, place the dialyzer in it, evaluate the results and perform any other maintenance function that the particular machine requires. An additional limitation of testing dialyzers in this way is that the dialyzer is tested in an environment remote from that in which it is used. Testing the dialyzer as part of the cleaning process does not take into account that the cleaning process or the preparation itself can damage the diaphragm. A desired method to test the integrity of the membrane would test the dialyzer in the same machine and in the same environment in which the dialyzer is used. It would be to check the integrity of the membrane just before the dialyzer is used, and it would be to use the current equipment currently used for the treatment with hemodialysis, thus being profitable for the user. COMPENDIUM OF THE INVENTION The present invention presents a method and apparatus for checking the integrity of a dialyzer before use. The method of the present invention provides an advantage over the prior art in that it can be performed in conjunction with current hardware used in the dialysis treatment. No special machines, valves or pressurized gas are required. Although described with respect to checking the dialyzer prior to its reuse, it is understandable that the method of the present invention can be performed on all dialyzers, not just reused dialyzers. A further advantage of the method of the present invention is that it can be carried out just before starting the dialysis treatment. Often, different machines, for example, those found in the prior art, clean, sterilize and check the dialyzer before use and do not take into consideration that the cleaning or the moving process can also cause damage to the dialyzer. Damage may occur even after the dialyzer has been checked and determined to be working well. The method of the present invention includes the following general steps. First, the dialyzer is enrolled in the normal way. The blood side is enriched with a saline solution and the dialysate side is enriched with a saline solution. Once enrolled, the blood hoses and hoses of the saline are attached. The hose that connects to the vein is vented to the atmosphere through the producer of the venous pressure tube transducer that maintains sterility on the blood side. Then, the flow rate of the ultrafiltrate is maximized. The prime volume on the blood side is ultrafiltered through the membrane and, in the long run, it is replaced by the air that has entered the circuit through the transduced protector. Then the pressure on the dialysate side is checked. Because the air can not pass through an intact membrane, as more air enters the blood compartment of the ultrafiltrate flow, the transmembrane pressure increases. Therefore, if the transmembrane pressure has increased, the membrane is intact and may be used for treatment. If, on the other hand, the pressure on the dialysate side has not increased, then the air must have passed through the membrane and the dialysate machine will not be able to increase the pressure because the circuit is open to the atmosphere. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 is a schematic representation showing the elements of the hemodialysis delivery system. Fig. 2 is a circuit diagram showing the preferred embodiment of the circulation diagram of the invention. Fig. 3 is a graph showing an example of the pressure gradients of the dialysis circuit for a successful test. Fig. 4 is a graph showing an example of the pressure gradients of the dialysis circuit for an unsuccessful test. Fig. 5 is a circulation diagram showing the preferred embodiment of the method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to Fig. 1, it can be easily appreciated that the practice of the method of the present invention does not require additional equipment and can be easily implemented using the normal hemodialysis treatment equipment, programmed for the test procedure. The method of the present invention is performed using the following apparatuses: a dialysis controller 10, a dialyzer 12 and the blood connecting hoses 16 and 18. In general, the controller 10 performs the basic function of regulating the flow rate, the pressure and the dialysate temperature. The normal characteristics of the controllers include a blood pump, heparin pump, an air detector, a blood leak detector, a dialysis fluid pump, blood monitors, dialysis fluid and ultrafiltration, as well as alarm circuits and automatic stop.

The dialyzer 12 consists of a compartment for the blood, a compartment for the dialysate and a membrane that separates both. The total surface area of the membrane measures 1 to 2 square meters. The membrane is a thin film with thousands of small holes that allow water and dissolved substances of small size to pass through, but it retains the proteins and blood cells, which are too large to pass through the membrane. During ultrafiltration of dialysis, hydrostatic pressure is exerted through the dialyzer membrane, causing the removal of excess fluid from the blood flow. The blood connecting hoses used in dialysis (16 and 18) function to connect the patient to the pump and the dialyzer, providing a reliable path for blood to and from the access site 14. A connecting hose for arterial blood 16 conducts the blood to the dialyzer while the connecting venous blood hose 18 drives the blood back to the patient. The practice of the method of the present invention is understandable with reference to Fig. 2. The dialyzer is prepared with saline in the normal manner before initiating hemodialysis treatment. Once enlisted, arterial blood connecting hose 16 is secured with clamp 46. The venous blood connecting hose 18 is vented to atmosphere 44 through the venous pressure hose transducer 26. The venous pressure hose transducer 26, which could be seen with reference to Fig. 1, maintains sterility intact on the blood side of the dialyzer 12. Returning to the analysis of Fig. 2, the flow rate of the ultrafiltrate 22 increases to a maximum of 3000 ml / hr. At this point, the prime volume on the blood side is ultrafiltered through the membrane. Because the venous blood connecting hose 18 is vented to the atmosphere 44, air now enters the circuit through the protector of the transducer 26 and fills the blood side of the dialyzer 12 where the prime of the blood side had previously been. the blood. When the prime of the blood side no longer exists, the transmembrane pressure is verified. In an intact membrane, air can not pass through it, so more air enters the blood compartment and there is less liquid priming to meet the demands of the ultrafiltrate flow rate, the transmembrane pressure increases to a value higher than 300 mmHg. If the pressure on the dialysate side has increased, the integrity of the dialyzer is confirmed and the dialyzer can be reused for dialysis treatment. This result can be seen with reference to Fig. 3. If the transmembrane pressure has not increased, then dialysis is more likely to leak material integrity and should not be used. This result is depicted in Fig. 4. In use, the method of the present invention generally functions as follows, as depicted in Fig. 5: while waiting for patients scheduled to receive dialysis treatment, the nurse or the The technician who works in that particular station prepares in the normal manner the blood side and dialysate dialysate sides, as well as the hoses connected with saline solution. The nurse or technician then stops the flow of the blood side to the dialyzer. Next, the nurse or technician presses the test button on the machine to apply the test that will evaluate the integrity of the dialyzer. The venous pressure monitoring hose is removed from the machine. The transmembrane pressure is verified by the normal pressure control mechanisms of the machine. If the transmembrane pressure has increased, the nurse or technician will know that the dialyzer can be reused. If the pressure on the dialysate side has not increased, the test fails and the nurse or technician knows that the dialyzer can not be used for additional treatment.

Claims (16)

1. CLAIMS 1. An apparatus for checking the integrity of the dialyzer before use, comprising: a dialysis control unit; a dialyzer with a compartment for blood and a compartment for dialysate, separated by a membrane; a pair of connecting hoses for blood; and a clamping device for holding the blood connector hoses. The apparatus of claim 1, wherein the blood connecting hoses include a venous blood connecting hose and an arterial blood connecting hose operatively connected to the dialysis control unit. The apparatus of claim 2, wherein the dialysis control unit includes mechanisms for increasing the flow rate of the dialysate through the dialysate compartment of the dialyzer. The apparatus of claim 3, wherein the dialysis control unit includes mechanisms for measuring the pressure within the dialysate compartment of the dialyzer. The apparatus of claim 4, wherein the dialysis control unit includes mechanisms for measuring the pressure within the blood compartment of the dialyzer. 6. A method for checking the integrity of the dialyzer before use, comprising: preparing a hemodialysis delivery system for the treatment with hemodialysis of a patient, including the hemodialysis delivery system a dialyzer; check the presence of leaks in the dialyzer, and apply the hemodialysis treatment to the patient. The method of claim 6, wherein the check comprises: connecting a first end of a blood connecting hose to the dialyzer; connecting a first end of a connecting hose for arterial blood to the dialyzer; venting the second end of the venous blood connector hose to the atmosphere; hold a second end of the connecting hose for arterial blood; Increase the flow rate of the dialysate through the dialysate side of the dialyzer, and check the transmembrane pressure to determine if a leak has occurred in the diaphragm. The method of claim 7, wherein the dialysate flow through the dialysate side of the dialyzer increases to a value of 3000 ml / hour. The method of claim 8, wherein the transmembrane pressure is compared to a value of 300 mmHg and further includes the step, after the checking step, of discarding the membrane if the transmembrane pressure is less than 300 mmHg. The method of claim 9, further comprising the step, before the check step, of enlisting the blood compartment side with saline. The method of claim 10, further comprising the step, before the check step, of enlisting the compartment on the dialysate side with saline. 12. A method for testing a dialyzer for the presence of leaks, comprising the steps of: connecting a dialysis patient to a hemodialysis delivery system, having a dialysis control unit with mechanisms for testing a transmembrane pressure , a dialyzer having a dialysate compartment, a blood compartment and a membrane between both, a venous blood connecting hose having a first and a second end; a blood connecting hose having first and second ends; apply the hemodialysis treatment to the patient; check the dialyzer in the hemodialysis delivery system, and apply hemodialysis in a second patient using the same hemodialysis delivery system if the dialyzer passes the test. 13. The method of claim 12, further comprising the steps, before the check step, of enlisting the dialysate compartment and the blood compartment with saline using a connection hose with saline. The method of claim 13, wherein the step of checking is comprised of the steps of: connecting a first end of the connecting venous blood hose to the dialyzer; connect the first end of the connecting hose for arterial blood to the dialyzer; hold the blood connector hose and the connection hose for saline; ventilate the venous hose; increase the flow rate of the ultrafiltrate, and check the transmembrane pressure to determine if there is a leak in the membrane. The method of claim 14, wherein the flow rate of the ultrafiltrate increases to the maximum value for the hemodialysis delivery system. The method of claim 15, wherein the transmembrane pressure is compared to a value of not less than 300 mmHg, and further comprising the step, after the checking step, of discarding the membrane if the pressure value transmembranous is less than 300 mmHg.